In the early 20th century, the prevailing trend was to study foods rich in phytochemicals and evaluate their bioactivity. Among all the berries, black chokeberry, Aronia melanocarpa, gained the most popularity as it is one of the richest plant sources of polyphenols(Reference Jurendić and Ščetar1). Polyphenols, particularly anthocyanins, exhibit strong antioxidant properties. The literature indicates that the antioxidant capacity of chokeberry juice is four times higher than in cranberry, blueberry or red grape juice(Reference Kasprzak-Drozd, Oniszczuk and Soja2).
Within the bioavailability framework, contemporary research has elucidated that the constituents of chokeberry are detectable in systemic circulation and excreted in urine at nanomolar concentrations. Furthermore, studies have identified glucuronidation and methylation as primary metabolic pathways in the biotransformation of chokeberry-derived anthocyanins. It is noteworthy that the bioavailability of these anthocyanins is significantly modulated by extensive metabolism conducted by gut microbiota in the colon. This complex metabolic process produces a diverse spectrum of low molecular weight phenolic metabolites, which exhibit enhanced bioavailability and superior absorption rates(Reference Zare, Kimble and Redha3).
According to the literature, black chokeberry Aronia melanocarpa exhibits strong antioxidant properties. The mechanisms underlying these properties are multifaceted, involving the enhancement and protection of enzymes such as paraoxonase, superoxide dismutase (SOD) and glutathione. Additionally, chokeberry inhibits the activity of several key enzymes involved in oxidative and inflammatory processes. Specifically, it reduces the activity of inducible nitric oxide synthase, which is responsible for producing nitric oxide in response to inflammatory stimuli and can contribute to oxidative stress and tissue damage. It also inhibits NADPH oxidase, an enzyme complex that generates reactive oxygen species (ROS) and plays a crucial role in the body’s defense mechanism and pathology of various diseases. Furthermore, chokeberry suppresses lipoxygenase, an enzyme involved in PUFA metabolism to form pro-inflammatory leukotrienes. By inhibiting these enzymes, chokeberry helps to mitigate oxidative stress and inflammation, contributing to its overall protective effects against various diseases(Reference Kasprzak-Drozd, Oniszczuk and Soja2,Reference Bowtell and Kelly4) . As other research shows, chokeberry anthocyanins also demonstrate protective effects against the oxidation of α- and γ-tocopherol(Reference Naruszewicz, Laniewska and Millo5). Research has shown that Aronia melanocarpa constituents can accumulate at the lipid bilayer-aqueous phase interface in erythrocyte membranes. Their localisation within the hydrophilic region of the membrane creates a protective barrier against free radicals, thereby enhancing the effectiveness and safety of these antioxidants(Reference Skarpańska-Stejnborn, Basta and Sadowska6).
Anthocyanins in black chokeberry also play a significant role in modulating inflammation. This regulatory effect is attributed to their ability to bind iron and regulate various immune system components involved in inflammatory processes(Reference Stankiewicz, Cieślicka and Kujawski7). The anti-inflammatory properties of black chokeberry are intricately linked to the enhancement of the human immune response. This involves the suppression of pro-inflammatory cytokines and the release of anti-inflammatory cytokines. The antiviral and antimicrobial properties of chokeberry additionally contribute to its anti-inflammatory effects(Reference Jurikova, Mlcek and Skrovankova8).
Scientific evidence supports aronia supplementation’s impact on clinical and sporting populations. This is mainly related to the activity of anthocyanin compounds, which have been shown to have strong antioxidant, anti-inflammatory and cardioprotective properties(Reference Jurendić and Ščetar1,Reference Bell and Gochenaur9) . In individuals with metabolic disorders, such as diabetes, obesity and CVD, oxidative stress and chronic inflammation are critical factors contributing to the progression of these conditions. Research indicates that aronia supplementation can mitigate these pathological processes by reducing oxidative stress markers and inflammatory cytokines, thereby improving metabolic parameters such as lipid profiles, blood glucose levels and insulin sensitivity(Reference Milutinovic, Velickovic Radovanovic and Šavikin10–Reference Le Sayec, Xu and Laiola12). Moreover, in healthy individuals, particularly athletes, the high-intensity physical exertion associated with training and competition leads to an increased production of ROS, which can result in oxidative damage to cells and tissues. The antioxidant capacity of aronia can help neutralise these ROS, thereby reducing exercise-induced oxidative stress. This can potentially enhance recovery, reduce muscle damage and improve overall athletic performance. The anti-inflammatory effects of aronia may also contribute to faster recovery times and reduced post-exercise soreness(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Mieszkowski13) .
Recent studies have established a connection between dysbiosis of the human gut and a variety of diseases, including obesity, diabetes, depression and irritable bowel syndrome. The gut microbiome plays a critical role in maintaining the integrity of the intestinal epithelial barrier, which is essential for the functional maturation of the gut immune system. Disruption of homeostasis in the gut can lead to systemic effects due to the leakage of the epithelial wall, allowing endotoxins and bacteria to enter systemic circulation and trigger endotoxemia and inflammatory responses. Polyphenols have been identified as modulators of the microbiome composition(Reference Hills, Pontefract and Mishcon14). There likely exists a bi-directional relationship between the human gut microbiome and polyphenols, mirroring the interaction between polyphenols and the microbial population in the root systems of plants(Reference Kennedy15). Aronia melanocarpa, a rich source of polyphenols, may have consequently a significant impact on the human gut microbiome, promoting gut health and potentially mitigating the risks associated with gut dysbiosis.
Therefore, this study focuses on a detailed investigation through literature, including all available articles from databases, to explore the impact of black chokeberry on oxidative stress, inflammation and intestinal parameters in both animal models and human subjects. Recognising the existence of prior research exploring the impacts of black chokeberry on these physiological factors, our systematic review distinguishes itself as the initial effort to amalgamate and integrate findings across these realms, providing a comprehensive elucidation of the biological effects of black chokeberry on living organisms. Furthermore, this comprehensive aggregation of research articles enables a detailed analysis of results attained to date, thereby identifying areas warranting further exploration and analysis.
This systematic review will address whether and how black chokeberry affects biomarkers of oxidative stress, inflammation and intestinal parameters and whether interactions exist between these biomarkers. Although there is ample evidence supporting the positive effects of chokeberry on oxidative stress, inflammation and intestinal parameters, the hypothesis carries some uncertainty. It should be noted that studies are conducted on different cohorts (animals, healthy individuals, patients, athletes) and the supplement comes in various forms (extract, juice, fresh fruit) and contains different concentrations of active compounds (anthocyanins, polyphenols). Additionally, the dose and duration of supplementation vary, and chokeberry is expected to affect various physiological and pathological states (high oxidative stress, inflammation, post-exercise recovery), each characterised by distinct mechanisms of action. Therefore, it is important to bear these limitations in mind when interpreting the results.
Materials and methods
Search strategy
This systematic literature review focused on the health benefits of black chokeberry (Aronia melanocarpa) supplementation. Due to the relatively low number of randomised controlled trials (RCT), animal model studies were also included in the review. For better interpretation and clarity, human and animal data were presented separately. The systematic review was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) principles. This study was registered with PROSPERO (International Prospective Register of Systematic Reviews) under registration number CRD42023395969. Electronic database searches were performed on the Web of Science, PubMed, Scopus and EBSCO. The search strategy for RCT and in vivo studies was the same by combining the words ‘aronia or chokeberry’ and ‘inflammation or oxidative stress or microbiota or microbiome or gut permeability or gut’. The reference list of retrieved literature reviews was then manually searched to find potential articles that could be included in the systematic review. The study used a protocol involving simultaneous searches and separate presentation of results. This was similarly performed by Groulx et al. (Reference Groulx, Emond and Boudreau-Drouin16). No restrictions on publication date or study type were applied to any search strategy. The search included original papers in English published before 01·05·2024.
Inclusion and exclusion criteria
The inclusion criteria used in the study:
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Articles in English language
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Participants: people of all ages, animals only in vivo
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Supplementation with black chokeberry in any form (i.e. juice, extract, diet) and any dose (if the exact dose used in the study is given)
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Published in full in a peer-reviewed journal
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RCT and clinical trial concerns
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Only the level 1 Oxford Centre for Evidence-Based Medicine scale (Table 1) concerns RCT
Table 1. The Oxford 2011 levels of evidence(17)
The exclusion criteria used in the study:
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In vitro testing
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The use of another kind of chokeberry (e.g. chokeberry ‘Viking’)
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Observational studies, meta-analysis, systematic review,
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Articles in not English language
Data extraction
Data were first evaluated by two investigators (S. K. and H. Dz.) and then was checked independently by two other supervisors (A. S-S. and A. K.). All articles were searched using the keywords. After that, all replicas were removed, and article abstracts were analysed based on the eligibility criteria. Finally, full texts of articles that met the eligibility criteria were analysed. Each publication selected for the review was critically evaluated. All articles’ full texts were available online. Independently extracted data from studies were entered into two tables (for the RCT and the animal model).
The table for the RCT studies included study information such as first author and year of publication, Oxford Centre for Evidence-Based Medicine (OCEBM) level, research and control group characteristics and size, type of supplement, dose, duration of supplementation and direction of change in inflammatory, oxidative stress or gut microbiota. The table for in vivo studies included information such as first author and year of publication, characteristics and size of the model and control group, type of supplement, dose, duration of supplementation and direction of change in inflammatory, oxidative stress or gut microbiota.
Quality assessment
Following the analyses described above, the level of evidence in the RCT was assessed by four independent reviewers (H. Dz., A. K., S. K., M. P.) using the 2011 Oxford Centre for Evidence-Based Medicine method, developed by an international group of researchers involving clinicians, patients and investigators (Table 1). The Oxford Centre for Evidence-Based Medicine method enables the rapid identification of the best evidence, encouraging clinicians, researchers and patients to autonomously evaluate the evidence.
Subsequently, a bias analysis of human studies was performed by two investigators (H. Dz., M. P.) using the latest version of the Cochrane collaboration risk-of-bias tool (Table 2), which is used in randomised trials(Reference Higgins, Altman and Gøtzsche18). Studies were screened in five areas: bias due to the randomisation process, bias due to deviations from the intended innervation, bias due to missing outcome data, bias in the outcome measure and bias in the choice of reported outcomes. This tool allows the investigator to classify each domain as high risk, of some concern, or low risk. Some concern was found mainly in the randomisation process.
Table 2. Cochrane collaboration risk-of-bias tool. Symbols used: +, low risk; ?, unclear risk; -, high risk
Analysis of bias of animal studies using the SYRCLE’s ROB tool (Table 3) was performed by two investigators (M.P., S.K.). The SYRCLE tool is based on the Cochrane Collaboration Tool but contains ten entries. These entries are related to six types of bias: selection bias, performance bias, detection bias, attrition bias, reporting bias and other biases(Reference Hooijmans, Rovers and de Vries19).
Table 3. SYRCLE’s risk-of-bias tool for animal studies. (1) sequence generation; (2) baseline characteristics; (3) allocation concealment; (4) random housing; (5) blinding of experimentalists; (6) random for outcome assessment; (7) blinding of outcome assessors; (8) incomplete outcome data; (9) selective outcome reporting; (10) other biases. Symbols used: +, low risk; ?, unclear risk; -, high risk
Statistical analyses
The quantitative data were presented in tables, without further statistics. The studies presented data in different formats and/or with different structures. Because of low heterogeneity in the studies (different cohorts, physiological states, supplement forms, doses and supplementation times), it was not possible to extract data for meta-analysis for statistical comparison. The summary tables contain data extracted from included studies containing participants’ characteristics, doses, duration of supplementation and outcomes.
Results
The literature searches identified 960 potential articles. After removing 536 duplicates, 424 records were subjected to article title and abstract screening. Subsequently, the full texts of 120 articles were meticulously examined, including fifty-seven articles in the review (Fig. 1). These articles have been categorised into two tables: Table 4 comprises studies conducted utilising animal models, while Table 5 encompasses studies involving human subjects.
Figure 1. PRISMA flow diagram illustrating the search and selection of studies.
Table 4. Summary of studies on the effects of chokeberry on inflammation, oxidative stress and intestinal parameters – an animal model
Abbreviations: ↔ No change; ↓ decrease; ↑ increase; ≠ not homogeneous; b.w., body weight; ACE, abundance-based coverage estimator; CAT, catalase; COX-2, cyclooxygenase-2; Chao1, total number of species in a sample; CRP, C-reactive protein; GSH-Px, glutathione peroxidase; GR, glutathione reductase; GST, glutathione transferases; IFN-γ, interferon-γ; H2O2, hydrogen peroxide; F/B ratio, Firmicutes:Bacteroides ratio; TLR4, toll-like receptor 4; PI3HO-1, haem oxygenase-1; MDA, malondialdehyde; MCP-1, monocyte chemoattractant protein-1; Nrf2, nuclear-related factor-2; PCoA, principal coordinate analysis; ROS, reactive oxygen species; SOD, superoxide dismutase; TAC, total antioxidant capacity; TGF-β1, transforming growth factor-β1; TAS, total antioxidative status; TBARS, thiobarbituric acid reactive substances; TOS, total oxidative; NO, nitric oxide.
Table 5. Summary of studies on the effects of chokeberry on inflammation, oxidative stress and intestinal parameters – human
Abbreviations: ↔ No change, ↓ decrease, ↑ increase; 8-OHdG, 8-hydroxy-2′-deoxyguanosine; CAT, catalase; CRP, C-reactive protein; GSH-Px, glutathione peroxidase; GR, glutathione reductase; MCP-1, monocyte chemoattractant protein-1; MDA, malondialdehyde; SOD, superoxide dismutase; TAC, total antioxidant capacity; TAS, total antioxidative status; TBARS, thiobarbituric acid reactive substances.
Studies conducted on an animal model
In Table 4, the total number of manuscripts is forty-five. The size of the groups is less than fifty in twenty-one articles(Reference Liu, Martin and Valdez21–Reference Rudic, Jakovljevic and Jovic23,Reference Kujawska, Ignatowicz and Ewertowska25,Reference Ma, Lyu and Deng27,Reference Piotrowska-Kempisty, Nowicki and Jodynis-Liebert29,Reference Ciocoiu, Badescu and Miron31,Reference Ćujić, Savikin and Miloradovic34–Reference Jiao, Shen and Deng36,Reference Yu, Kim and Park40–Reference Jeong, Liu and Kim43,Reference Song, Park and Kim45,Reference Zhao, Liu and Zheng46,Reference Lipińska, Atanasov and Palka50,Reference Valcheva-Kuzmanova, Marazova and Krasnaliev53,Reference Xing, Liang and Zhang56,Reference Liu, Zhang and Gao57,Reference Wilson, Peach and Fausset62,Reference Doma, Cristina and Dumitrescu63) . The group size in the range of 50–100 is fourteen articles(Reference Zhao, Liu and Ding20,Reference Li, Li and Xu24,Reference Wei, Zhang and Zhang26,Reference Yang, Gao and Yu28,Reference Dąbrowski, Onopiuk and Car30,Reference Wang, Wang and Yan33,Reference Valcheva-Kuzmanova, Stavreva and Dancheva38,Reference Liu, Ju and Bao39,Reference Zhu, Wei and Karras47,Reference Frankiewicz-Jóźko and Faff49,Reference Onopiuk, Dąbrowska and Rogalska52,Reference Dąbrowska, Dąbrowska and Onopiuk55,Reference Wei, Zhang and Tang58,Reference Wang, Liu and Zhao71) . More than a group size of more than 100 participants is found in seven articles(Reference Mężyńska, Brzóska and Rogalska32,Reference Jing, Xiao and Yin37,Reference Brzóska, Tomczyk and Rogalska48,Reference Mężyńska, Brzóska and Rogalska54,Reference Wang, Cong and Qu59–Reference Ruczaj, Brzóska and Rogalska61) . Moreover, twelve articles were about females(Reference Rudic, Jakovljevic and Jovic23,Reference Dąbrowski, Onopiuk and Car30,Reference Mężyńska, Brzóska and Rogalska32,Reference Jing, Xiao and Yin37,Reference Liu, Ju and Bao39,Reference Ren, Fang, Zhang and Wang41,Reference Onopiuk, Dąbrowska and Rogalska52,Reference Mężyńska, Brzóska and Rogalska54,Reference Dąbrowska, Dąbrowska and Onopiuk55,Reference Liu, Zhang and Gao57,Reference Smereczański, Brzóska and Rogalska60,Reference Ruczaj, Brzóska and Rogalska61) . Four articles(Reference Ciocoiu, Badescu and Miron31,Reference Lipińska, Atanasov and Palka50,Reference Wang, Cong and Qu59,Reference Doma, Cristina and Dumitrescu63) lack clearly defined sex of animals, while two articles discuss both males and females(Reference Pavlova, Sainova and Alexieva35,Reference Wilson, Peach and Fausset62) . In other papers, the research was performed with males. Markers of oxidative stress were analysed in thirty-six articles(Reference Zhao, Liu and Ding20,Reference Zhao, Liu and Ding20,Reference Rudic, Jakovljevic and Jovic23–Reference Pavlova, Sainova and Alexieva35,Reference Jing, Xiao and Yin37–Reference Liu, Ju and Bao39,Reference Ren, Fang, Zhang and Wang41–Reference Jeong, Liu and Kim43,Reference Song, Park and Kim45,Reference Brzóska, Tomczyk and Rogalska48–Reference Lipińska, Atanasov and Palka50,Reference Onopiuk, Dąbrowska and Rogalska52–Reference Xing, Liang and Zhang56,Reference Wei, Zhang and Tang58–Reference Ruczaj, Brzóska and Rogalska61,Reference Doma, Cristina and Dumitrescu63,Reference Wang, Liu and Zhao71) , while indicators of inflammation were determined in seventeen studies(Reference Zhao, Liu and Ding20,Reference Li, Li and Xu24,Reference Wei, Zhang and Zhang26,Reference Yang, Gao and Yu28,Reference Piotrowska-Kempisty, Nowicki and Jodynis-Liebert29,Reference Wang, Wang and Yan33,Reference Jiao, Shen and Deng36,Reference Valcheva-Kuzmanova, Stavreva and Dancheva38–Reference Ren, Fang, Zhang and Wang41,Reference Jeong, Liu and Kim43,Reference Ohgami, Ilieva and Shiratori44,Reference Gajic, Saksida and Koprivica51,Reference Liu, Zhang and Gao57,Reference Wei, Zhang and Tang58,Reference Wang, Liu and Zhao71) . Changes in gut microbiota were studied in eight articles(Reference Zhao, Liu and Ding20,Reference Zhu, Zhang and Wei22,Reference Liu, Ju and Bao39,Reference Ren, Fang, Zhang and Wang41,Reference Zhao, Liu and Zheng46,Reference Zhu, Wei and Karras47,Reference Xing, Liang and Zhang56,Reference Wilson, Peach and Fausset62) .
Studies conducted with humans
In Table 5, the total number of articles is twelve. The group size is less than fifty in nine articles(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Kujawski7,Reference Duchnowicz, Nowicka and Koter-Michalak11,Reference Stankiewicz, Cieślicka and Mieszkowski13,Reference Broncel, Kozirog and Duchnowicz64–Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67,Reference Chung, Kim and Nam69,Reference Lackner, Mahnert and Moissl-Eichinger70) . A group size of more than fifty participants occurs in three articles(Reference Le Sayec, Xu and Laiola12,Reference Istas, Wood, Le Sayec and Rawlings68,Reference Chung, Kim and Nam69) . Five articles involved only men(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Kujawski7,Reference Stankiewicz, Cieślicka and Mieszkowski13,Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67,Reference Istas, Wood, Le Sayec and Rawlings68) , and the remaining six manuscripts involved both sexes(Reference Duchnowicz, Nowicka and Koter-Michalak11,Reference Le Sayec, Xu and Laiola12,Reference Broncel, Kozirog and Duchnowicz64–Reference Xie, Vance and Kim66,Reference Chung, Kim and Nam69) . One article focused on women(Reference Lackner, Mahnert and Moissl-Eichinger70). In five articles, the participants were athletes(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Kujawski7,Reference Stankiewicz, Cieślicka and Mieszkowski13,Reference Petrovic, Arsic and Glibetic65,Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67) , the other two manuscripts were about patients(Reference Duchnowicz, Nowicka and Koter-Michalak11,Reference Broncel, Kozirog and Duchnowicz64) and the remaining articles refer to healthy people(Reference Le Sayec, Xu and Laiola12,Reference Xie, Vance and Kim66,Reference Istas, Wood, Le Sayec and Rawlings68–Reference Lackner, Mahnert and Moissl-Eichinger70) . Markers of oxidative stress were analysed in nine articles(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Kujawski7,Reference Duchnowicz, Nowicka and Koter-Michalak11,Reference Stankiewicz, Cieślicka and Mieszkowski13,Reference Broncel, Kozirog and Duchnowicz64–Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67,Reference Chung, Kim and Nam69) . Indicators of inflammation were analysed in five manuscripts(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Kujawski7,Reference Stankiewicz, Cieślicka and Mieszkowski13,Reference Xie, Vance and Kim66,Reference Chung, Kim and Nam69) , while intestinal parameters were indicated in only three(Reference Le Sayec, Xu and Laiola12,Reference Istas, Wood, Le Sayec and Rawlings68,Reference Lackner, Mahnert and Moissl-Eichinger70) .
Effect of chokeberry on prooxidant–antioxidant balance parameters – human
Of the human studies, eight analysed markers were related to prooxidant–antioxidant balance, that is, thiobarbituric acid reactive substances (TBARS), GSH, SOD, catalase (CAT), total antioxidant capacity (TAC), glutathione peroxidase (GSH-Px), GSSG and malondialdehyde (MDA). Reduced levels of lipid peroxidation expressed as TBARS were observed in five studies(Reference Stankiewicz, Cieślicka and Kujawski7,Reference Duchnowicz, Nowicka and Koter-Michalak11,Reference Broncel, Kozirog and Duchnowicz64,Reference Petrovic, Arsic and Glibetic65,Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67) . Only one experiment showed no change in TBARS concentration(Reference Stankiewicz, Cieślicka and Kujawski7). One manuscript analysed GSH levels and showed a decrease in concentration(Reference Chung, Kim and Nam69). The value of SOD was analysed in four studies(Reference Broncel, Kozirog and Duchnowicz64,Reference Xie, Vance and Kim66,Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67,Reference Chung, Kim and Nam69) . In two manuscripts, no changes in SOD levels were observed(Reference Xie, Vance and Kim66,Reference Chung, Kim and Nam69) . One article showed an increase or no change depending on the length of supplementation(Reference Broncel, Kozirog and Duchnowicz64), and one manuscript showed a decrease in SOD levels(Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67). As for CAT, in one paper, there was a decrease in CAT concentration(Reference Broncel, Kozirog and Duchnowicz64). No change in CAT values was observed in two articles(Reference Xie, Vance and Kim66,Reference Chung, Kim and Nam69) . Only three manuscripts analysed the level of TAC values(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Kujawski7,Reference Stankiewicz, Cieślicka and Mieszkowski13) . Two exhibits showed an increase in TAC values(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Mieszkowski13) , and the other showed no change(Reference Stankiewicz, Cieślicka and Kujawski7). The GSH-Px index was analysed in three papers(Reference Xie, Vance and Kim66,Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67,Reference Chung, Kim and Nam69) . Two manuscripts showed a decrease in levels(Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67,Reference Chung, Kim and Nam69) . One paper showed no change in values. The GSSG parameter was analysed in only one article, where a reduction in values was observed(Reference Chung, Kim and Nam69). Similarly, the biomarker MDA was analysed in only one manuscript where no changes were shown(Reference Chung, Kim and Nam69).
Effect of chokeberry on inflammation – human
Inflammation was analysed in five papers. IL-6 levels were analysed in five papers(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Kujawski7,Reference Stankiewicz, Cieślicka and Mieszkowski13,Reference Xie, Vance and Kim66,Reference Chung, Kim and Nam69) . In three manuscripts, no changes were observed(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Stankiewicz, Cieślicka and Kujawski7,Reference Xie, Vance and Kim66) , while one experiment showed an increase in IL-6 levels(Reference Chung, Kim and Nam69), and one study showed a decrease(Reference Stankiewicz, Cieślicka and Mieszkowski13). TNF-α levels were analysed in two manuscripts(Reference Skarpańska-Stejnborn, Basta and Sadowska6,Reference Xie, Vance and Kim66) . One paper showed no change(Reference Xie, Vance and Kim66), and one paper observed a decrease in levels(Reference Skarpańska-Stejnborn, Basta and Sadowska6). Myoglobin levels were analysed in only one manuscript, where no changes were shown(Reference Stankiewicz, Cieślicka and Kujawski7). IL-1β levels were studied in one study, which showed no change(Reference Xie, Vance and Kim66). The C-reactive protein biomarker was analysed in one manuscript, and no changes were observed(Reference Xie, Vance and Kim66).
Effect of chokeberry on gut health – human
There were only three articles on humans considering gut health(Reference Le Sayec, Xu and Laiola12,Reference Istas, Wood, Le Sayec and Rawlings68,Reference Lackner, Mahnert and Moissl-Eichinger70) . Nevertheless, α and β diversity remained unchanged(Reference Le Sayec, Xu and Laiola12,Reference Istas, Wood, Le Sayec and Rawlings68) , Bacteroides and its representative Bacteroides xylanisolvens increased(Reference Le Sayec, Xu and Laiola12,Reference Istas, Wood, Le Sayec and Rawlings68) and Haemophilus parainfluenzae decreased in one study(Reference Le Sayec, Xu and Laiola12).
Effect of chokeberry on prooxidant–antioxidant balance parameters – an animal model
In thirty-six studies conducted on animal models, the effects of chokeberry on markers of antioxidation–peroxidation balance were measured, that is, GSH, GSH-Px, SOD, MDA, O2, H2O2, HO–1, TBARS, CAT, glutathione reductase, total antioxidative status (TAS), ROS, TAC, nuclear-related factor-2 (Nrf2) and TOS. The GSH index was analysed in nineteen manuscripts(Reference Zhao, Liu and Ding20,Reference Rudic, Jakovljevic and Jovic23–Reference Kujawska, Ignatowicz and Ewertowska25,Reference Yang, Gao and Yu28,Reference Dąbrowski, Onopiuk and Car30,Reference Pavlova, Sainova and Alexieva35,Reference Ren, Fang, Zhang and Wang41,Reference Frankiewicz-Jóźko and Faff49,Reference Lipińska, Atanasov and Palka50,Reference Valcheva-Kuzmanova, Marazova and Krasnaliev53,Reference Dąbrowska, Dąbrowska and Onopiuk55,Reference Smereczański, Brzóska and Rogalska60,Reference Ruczaj, Brzóska and Rogalska61,Reference Doma, Cristina and Dumitrescu63) . Eight articles showed an increase in the biomarker(Reference Zhao, Liu and Ding20,Reference Rudic, Jakovljevic and Jovic23,Reference Li, Li and Xu24,Reference Yang, Gao and Yu28,Reference Ciocoiu, Badescu and Miron31,Reference Pavlova, Sainova and Alexieva35,Reference Frankiewicz-Jóźko and Faff49,Reference Lipińska, Atanasov and Palka50) , while the rest showed no change(Reference Kujawska, Ignatowicz and Ewertowska25,Reference Ren, Fang, Zhang and Wang41,Reference Valcheva-Kuzmanova, Marazova and Krasnaliev53,Reference Doma, Cristina and Dumitrescu63) . In the seven studies, the change varied at different time points(Reference Dąbrowski, Onopiuk and Car30,Reference Mężyńska, Brzóska and Rogalska32,Reference Onopiuk, Dąbrowska and Rogalska52,Reference Mężyńska, Brzóska and Rogalska54,Reference Dąbrowska, Dąbrowska and Onopiuk55,Reference Smereczański, Brzóska and Rogalska60,Reference Ruczaj, Brzóska and Rogalska61) . The GSH-Px parameter was analysed in twenty-three studies, and in fourteen studies observed an increase in its concentration(Reference Wei, Zhang and Zhang26,Reference Ma, Lyu and Deng27,Reference Piotrowska-Kempisty, Nowicki and Jodynis-Liebert29,Reference Ciocoiu, Badescu and Miron31–Reference Wang, Wang and Yan33,Reference Jing, Xiao and Yin37,Reference Liu, Ju and Bao39,Reference Brzóska, Tomczyk and Rogalska48,Reference Lipińska, Atanasov and Palka50,Reference Onopiuk, Dąbrowska and Rogalska52,Reference Mężyńska, Brzóska and Rogalska54,Reference Xing, Liang and Zhang56,Reference Wang, Liu and Zhao71) . Most of the six studies showed no change(Reference Kujawska, Ignatowicz and Ewertowska25,Reference Ćujić, Savikin and Miloradovic34,Reference Kim, Ku and Pham42,Reference Song, Park and Kim45,Reference Smereczański, Brzóska and Rogalska60,Reference Doma, Cristina and Dumitrescu63) . In the three studies, the change varied at different time points(Reference Dąbrowski, Onopiuk and Car30,Reference Dąbrowska, Dąbrowska and Onopiuk55,Reference Ruczaj, Brzóska and Rogalska61) . The SOD biomarker was analysed in twenty-nine papers. In eleven articles, an increase was observed(Reference Zhao, Liu and Ding20,Reference Li, Li and Xu24,Reference Wei, Zhang and Zhang26–Reference Yang, Gao and Yu28,Reference Wang, Wang and Yan33,Reference Jing, Xiao and Yin37,Reference Zhao, Liu and Zheng46,Reference Brzóska, Tomczyk and Rogalska48,Reference Wang, Cong and Qu59,Reference Wang, Liu and Zhao71) . Eight manuscripts showed no change(Reference Rudic, Jakovljevic and Jovic23,Reference Piotrowska-Kempisty, Nowicki and Jodynis-Liebert29,Reference Liu, Ju and Bao39,Reference Ren, Fang, Zhang and Wang41,Reference Kim, Ku and Pham42,Reference Song, Park and Kim45,Reference Xing, Liang and Zhang56,Reference Doma, Cristina and Dumitrescu63) , while three articles showed a decrease in SOD levels(Reference Kujawska, Ignatowicz and Ewertowska25,Reference Ćujić, Savikin and Miloradovic34,Reference Lipińska, Atanasov and Palka50) . In the seven studies, the change varied at different time points(Reference Dąbrowski, Onopiuk and Car30,Reference Mężyńska, Brzóska and Rogalska32,Reference Onopiuk, Dąbrowska and Rogalska52,Reference Mężyńska, Brzóska and Rogalska54,Reference Dąbrowska, Dąbrowska and Onopiuk55,Reference Smereczański, Brzóska and Rogalska60,Reference Ruczaj, Brzóska and Rogalska61) . The MDA index was determined in seventeen manuscripts, with thirteen articles showing a decrease(Reference Zhao, Liu and Ding20,Reference Li, Li and Xu24,Reference Ma, Lyu and Deng27,Reference Ciocoiu, Badescu and Miron31,Reference Wang, Wang and Yan33,Reference Jing, Xiao and Yin37,Reference Ren, Fang, Zhang and Wang41,Reference Jeong, Liu and Kim43,Reference Zhao, Liu and Zheng46,Reference Xing, Liang and Zhang56,Reference Wang, Cong and Qu59,Reference Wang, Liu and Zhao71) and the rest showing no change(Reference Wei, Zhang and Zhang26,Reference Valcheva-Kuzmanova, Stavreva and Dancheva38,Reference Song, Park and Kim45,Reference Valcheva-Kuzmanova, Marazova and Krasnaliev53) . The TBARS biomarker was determined in seven manuscripts. Its reduction was observed in five articles(Reference Rudic, Jakovljevic and Jovic23–Reference Kujawska, Ignatowicz and Ewertowska25,Reference Piotrowska-Kempisty, Nowicki and Jodynis-Liebert29,Reference Ćujić, Savikin and Miloradovic34) , while no change was observed in two(Reference Frankiewicz-Jóźko and Faff49,Reference Doma, Cristina and Dumitrescu63) . The parameters H2O2 were determined in six articles. A reduction was observed in three articles(Reference Rudic, Jakovljevic and Jovic23,Reference Mężyńska, Brzóska and Rogalska32,Reference Brzóska, Tomczyk and Rogalska48) . In the three studies, the change varied at different time points(Reference Onopiuk, Dąbrowska and Rogalska52,Reference Smereczański, Brzóska and Rogalska60,Reference Ruczaj, Brzóska and Rogalska61) . In one study, an increase in the concentration of HO– 1 (Reference Zhao, Liu and Zheng46) was observed, and in another, a decrease(Reference Wei, Zhang and Tang58). The CAT biomarker was studied in twenty-three manuscripts. Eleven articles showed an increase in concentration(Reference Rudic, Jakovljevic and Jovic23,Reference Li, Li and Xu24,Reference Piotrowska-Kempisty, Nowicki and Jodynis-Liebert29,Reference Dąbrowski, Onopiuk and Car30,Reference Wang, Wang and Yan33,Reference Kim, Ku and Pham42,Reference Zhao, Liu and Zheng46,Reference Brzóska, Tomczyk and Rogalska48,Reference Wang, Cong and Qu59,Reference Ruczaj, Brzóska and Rogalska61,Reference Wang, Liu and Zhao71) , seven studies showed no change(Reference Kujawska, Ignatowicz and Ewertowska25,Reference Ćujić, Savikin and Miloradovic34,Reference Liu, Ju and Bao39,Reference Ren, Fang, Zhang and Wang41,Reference Song, Park and Kim45,Reference Xing, Liang and Zhang56,Reference Doma, Cristina and Dumitrescu63) , and in five articles, the change varied at different time points(Reference Mężyńska, Brzóska and Rogalska32,Reference Onopiuk, Dąbrowska and Rogalska52,Reference Mężyńska, Brzóska and Rogalska54,Reference Dąbrowska, Dąbrowska and Onopiuk55,Reference Smereczański, Brzóska and Rogalska60) . The glutathione reductase biomarker was analysed in eight manuscripts. No changes were observed in three studies(Reference Kujawska, Ignatowicz and Ewertowska25,Reference Piotrowska-Kempisty, Nowicki and Jodynis-Liebert29,Reference Doma, Cristina and Dumitrescu63) . The level was lower in one manuscript(Reference Brzóska, Tomczyk and Rogalska48), and in four studies, the change varied at different time points(Reference Mężyńska, Brzóska and Rogalska32,Reference Mężyńska, Brzóska and Rogalska54,Reference Smereczański, Brzóska and Rogalska60,Reference Ruczaj, Brzóska and Rogalska61) . The TOS and TAS index were determined in four studies with the change varying at different points in time(Reference Brzóska, Tomczyk and Rogalska48,Reference Onopiuk, Dąbrowska and Rogalska52,Reference Smereczański, Brzóska and Rogalska60,Reference Ruczaj, Brzóska and Rogalska61) . The TAC biomarker was analysed in four manuscripts. Three papers showed an increased concentration(Reference Ciocoiu, Badescu and Miron31,Reference Jing, Xiao and Yin37,Reference Ren, Fang, Zhang and Wang41) , while two more showed no change(Reference Liu, Ju and Bao39). Nrf2 was determined in four studies, and an increase in its concentration was observed in all of them(Reference Ma, Lyu and Deng27,Reference Jing, Xiao and Yin37,Reference Zhao, Liu and Zheng46,Reference Wang, Cong and Qu59) .
Effect of chokeberry on inflammation – an animal model
Indicators of inflammation were determined in seventeen manuscripts. TNF-α was the most frequently analysed biomarker; in eight out of ten articles, a reduction was observed(Reference Yang, Gao and Yu28,Reference Wang, Wang and Yan33,Reference Jiao, Shen and Deng36,Reference Yu, Kim and Park40,Reference Ren, Fang, Zhang and Wang41,Reference Ohgami, Ilieva and Shiratori44,Reference Liu, Zhang and Gao57,Reference Wei, Zhang and Tang58) , while one study showed no change(Reference Piotrowska-Kempisty, Nowicki and Jodynis-Liebert29). One study observed no change before renal injury and a reduction after renal injury(Reference Li, Li and Xu24). IL-6 was the second most frequently analysed biomarker, with eight manuscripts showing a reduction(Reference Yang, Gao and Yu28,Reference Wang, Wang and Yan33,Reference Jiao, Shen and Deng36,Reference Valcheva-Kuzmanova, Stavreva and Dancheva38,Reference Ren, Fang, Zhang and Wang41,Reference Liu, Zhang and Gao57,Reference Wei, Zhang and Tang58,Reference Wang, Liu and Zhao71) . One study showed no change before kidney injury and a reduction after kidney injury(Reference Li, Li and Xu24). IL-1β levels were determined in five manuscripts. Four papers showed its reduction(Reference Wang, Wang and Yan33,Reference Jiao, Shen and Deng36,Reference Ren, Fang, Zhang and Wang41,Reference Liu, Zhang and Gao57) , while one paper observed no change before kidney injury and a reduction after kidney injury(Reference Li, Li and Xu24). NF-kB factor was also analysed in four studies. In each study, the results indicated a decrease in concentration(Reference Jiao, Shen and Deng36,Reference Yu, Kim and Park40,Reference Jeong, Liu and Kim43,Reference Zhao, Liu and Zheng46) . IL-10 was determined in three articles, with two papers showing a reduction(Reference Wang, Wang and Yan33,Reference Ren, Fang, Zhang and Wang41) and one showing no change(Reference Valcheva-Kuzmanova, Stavreva and Dancheva38). IL-1 was determined in three manuscripts, and reductions were observed(Reference Wei, Zhang and Zhang26,Reference Yang, Gao and Yu28,Reference Wei, Zhang and Tang58) . The COX2 index in the two articles was reduced(Reference Wei, Zhang and Zhang26,Reference Yang, Gao and Yu28) . Similarly, the transforming growth factor-β1 index was determined in two articles(Reference Wei, Zhang and Zhang26,Reference Piotrowska-Kempisty, Nowicki and Jodynis-Liebert29) .
Effect of chokeberry on gut health – an animal model
Eight research teams checked gut health in an animal model(Reference Zhao, Liu and Ding20–Reference Zhu, Zhang and Wei22,Reference Ren, Fang, Zhang and Wang41,Reference Zhao, Liu and Zheng46,Reference Zhu, Wei and Karras47,Reference Xing, Liang and Zhang56,Reference Wilson, Peach and Fausset62) . A diversity was raised in three studies(Reference Liu, Ju and Bao39,Reference Zhu, Wei and Karras47,Reference Wilson, Peach and Fausset62) and remained unchanged in three studies(Reference Zhu, Zhang and Wei22,Reference Ren, Fang, Zhang and Wang41,Reference Zhu, Wei and Karras47) ; in one study, this indicator decreased(Reference Zhao, Liu and Ding20). Four studies found an increase in Bacteroides and Bacteroidetes (Reference Zhu, Zhang and Wei22,Reference Ren, Fang, Zhang and Wang41,Reference Zhao, Liu and Zheng46,Reference Zhu, Wei and Karras47) . The Firmicutes:Bacteroides ratio is inconclusive; it decreased in two studies(Reference Zhu, Zhang and Wei22,Reference Zhu, Wei and Karras47) . Phyla Verrucomicrobia increased in two studies(Reference Zhu, Zhang and Wei22,Reference Zhu, Wei and Karras47) ; also, Prevotella increased in three studies(Reference Zhu, Zhang and Wei22,Reference Ren, Fang, Zhang and Wang41,Reference Zhu, Wei and Karras47) .
Discussion
Effects of black chokeberry on prooxidant–antioxidant balance parameters
After a thorough review of the available research, it can be concluded that compounds derived from chokeberry offer significant efficacy in reducing oxidative stress. This reduction is associated with the scavenging of free radicals, inhibition of lipid peroxidation and modulation of both enzymatic and non-enzymatic antioxidant activities(Reference Zhao, Liu and Ding20,Reference Li, Li and Xu24,Reference Ma, Lyu and Deng27,Reference Wang, Liu and Zhao71) . Nevertheless, the interplay among specific biomarkers fluctuates across studies conducted on diverse cohorts, employing varying supplementation doses and durations. For instance, Zhao et al. administered chokeberry extract at doses of 200 and 400 mg/kg b.w./d to mice with thioacetamide-induced liver fibrosis over 4 weeks. Their findings indicated an increase in glutathione (GSH) levels, associated with elevated SOD levels and a decrease in MDA levels (see Table 4)(Reference Zhao, Liu and Ding20). Li et al. also obtained analogous findings, by administering a blend of anthocyanins at a dose of 50 mg/g body weight, equivalent to 25 ml/g body weight, twice a day for 14 d to mice afflicted with kidney ischaemia-reperfusion injury. They noted increased glutathione (GSH), SOD and catalase (CAT) levels, with a reduction in MDA and TBARS (see Table 4). These observations underscore a favourable correlation between enzymatic and non-enzymatic antioxidant activity and lipid peroxidation, confirming the beneficial effects of chokeberry(Reference Zhao, Liu and Ding20,Reference Li, Li and Xu24) . In contrast, Ćujić et al. conducted a study where hypertensive rats were administered 50 mg/kg b.w./d of black chokeberry extract for 28 d, which led to a decrease in both TBARS and SOD levels. Ćujić suggests that the reduced SOD activity may be attributed to the chokeberry compounds’ capacity to scavenge superoxide anions, consequently lowering the substrate (superoxide anions) required for the SOD dismutation reaction (see Table 4)(Reference Ćujić, Savikin and Miloradovic34). In contrast, Rudic et al. supplemented female rats with chokeberry extract at a dose of 0·45 ml/kg b.w. per d for 28 d, observing an increase in GSH and CAT levels, no change in SOD levels and a decrease in TBARS levels. The elevation in GSH may account for the inhibition of lipid peroxidation and the subsequent decrease in TBARS; however, the reason for the increased CAT without a concurrent change in SOD remains unclear (see Table 4)(Reference Rudic, Jakovljevic and Jovic23). Some researchers propose that an increase in one antioxidant may prompt a compensatory decrease in another due to converse reactions(Reference Ohgami, Ilieva and Shiratori44).
Liu et al. supplemented pigs with a chokeberry-rich diet for 28 d but observed no changes in SOD, CAT and TAC biomarkers. They attribute this discrepancy to the need for polyphenols present in black chokeberry to be hydrolysed by microbes or endogenous enzymes, limiting their bioavailability to monogastric animals (Table 4)(Reference Liu, Ju and Bao39). Additionally, discussing the observed positive effects of black chokeberry following long-term supplementation could provide valuable insights. Dabrowski et al., for example, demonstrated the beneficial effects of long-term administration of black chokeberry extract, both alone and in Cd poisoning models, in rats. They noted increased SOD activity and TAS values, along with decreased TOS levels, after 10 months of chokeberry extract administration, affirming the antioxidant properties of the extract (Table 4)(Reference Dąbrowski, Onopiuk and Car30).
There is considerably less research on humans compared with animal models. Furthermore, comparing studies involving humans is complicated by the diversity of study groups, which include athletes, healthy individuals and patients with various conditions. For example, Duchnowicz et al. supplemented patients with hypercholesterolaemia with 300 ml/d of chokeberry extract for 2 months, observing a reduction in TBARS levels (see Table 5)(Reference Duchnowicz, Nowicka and Koter-Michalak11). Broncel et al. administered the same dose and duration of chokeberry extract to patients with metabolic syndrome. They reported reductions in TBARS and CAT levels and increases in GSH-Px and SOD indices after 1 month of supplementation. The researchers suggested that anthocyanins could serve as direct substrates for peroxidases, leading to the deactivation of hydrogen peroxide and thereby increasing GSH-Px activity. Additionally, they explained that hydrogen peroxide is deactivated in two reactions catalysed by CAT and GSH-Px; thus, high GSH-Px activity reduces the substrate concentration for CAT, inhibiting CAT activity via negative feedback (see Table 5)(Reference Broncel, Kozirog and Duchnowicz64). In contrast, Chung et al. used 300 mg/d of chokeberry extract for 8 weeks in healthy subjects. The researchers showed a statistically significant increase in GSH and GSH-Px concentrations and no significant changes in CAT, SOD and MDA concentrations. The explanation provided by Chung et al. indicates that the glutathione defense system was most sensitive in response to exercise used as a ‘factor’ to disrupt the prooxidant–antioxidant balance. However, unlike the glutathione defense system, SOD and CAT remained stable in the proposed model. This may indicate that the antioxidant enzyme response is dependent on the ‘severity’ of oxidative stress (Table 5)(Reference Chung, Kim and Nam69). Thus, discrepancies in antioxidant enzyme activity may be, at least partially, attributed to differences in the pathological conditions responsible for oxidation–antioxidation imbalance.
Analysing studies on athletes, in whom oxidative stress arose as a response to an intense physical exertion, we also observed the effectiveness of chokeberry supplements. Researchers often confirm this by demonstrating a reduction in TBARS concentrations(Reference Petrovic, Arsic and Glibetic65,Reference Pilaczynska-Szczesniak, Skarpanska-Steinborn and Deskur67) (see Table 5). However, given the recent systematic review that focused on the effects of chokeberry in a model of exercise(Reference Zare, Kimble and Redha3), we omit further analysis.
In summary, studies conducted on both animal models and human subjects collectively affirm the antioxidant properties of Aronia melanocarpa. This is primarily evidenced by alterations in the concentration of enzymes crucial for maintaining the balance between oxidation and antioxidation. However, the biomarkers analysed do not always exhibit expected behaviour. It can be inferred that the impact on antioxidant enzyme levels is contingent upon two factors: first, the severity of oxidative stress, which is influenced by the characteristics of the study population, and second, the content of biologically active compounds that directly mitigate oxidative stress, which is related to the dose, type of supplement administered (e.g. juice, extract, fruit) and the duration of supplementation.
Effects of black chokeberry on markers of inflammation
After analysing the findings from the systematic review, it is evident that the bioactive compounds in black chokeberry exert significant anti-inflammatory effects by modulating cytokine profiles. This modulation involves a complex interplay between various pro-inflammatory and anti-inflammatory mediators within the immune system. In animal models (see Table 4), it has been shown, that these compounds can reduce the levels of pro-inflammatory cytokines such as IL-1β (Reference Li, Li and Xu24,Reference Wang, Wang and Yan33,Reference Jiao, Shen and Deng36,Reference Ren, Fang, Zhang and Wang41) and TNF-α (Reference Li, Li and Xu24,Reference Yang, Gao and Yu28,Reference Wang, Wang and Yan33,Reference Jiao, Shen and Deng36,Reference Valcheva-Kuzmanova, Stavreva and Dancheva38,Reference Ren, Fang, Zhang and Wang41,Reference Wang, Liu and Zhao71) , which act as primary inflammatory stimuli during the cell signalling process.
To elucidate the impact of chokeberry on inflammation, oxidative stress and their interactions, it is critical to examine the role of AMP-activated protein kinase (AMPK), which modulates the NF-κB and Nrf2 pathways(Reference Jeong, Liu and Kim43,Reference Salminen, Hyttinen and Kaarniranta72) . Nrf2 is a pivotal regulator of various antioxidants and oversees the activity of antioxidant enzymes, including haem oxygenase-1, catalase (CAT), SOD and GSH-Px(Reference Jeong, Liu and Kim43). According to Zhao et al., black chokeberry influences AMPK activation, leading to the inhibition of the mammalian target of rapamycin activity. This subsequently activates the P-phosphatidylinositol-3-hydroxykinase/Akt/mammalian target of rapamycin pathway through the regulation of Nrf2 nuclear translocation, resulting in enhanced production of antioxidant enzymes(Reference Zhao, Liu and Zheng46). However, the direct phosphorylation effect of AMPK on Nrf2 remains to be clarified(Reference Petsouki, Cabrera and Heiss73).
NF-κB is a transcription factor that triggers the production of pro-inflammatory factors(Reference Li, Li and Xu24). AMPK activation stimulates factors such as sirtuin 1, PPAR gamma coactivator 1α, tumour protein p53 and FoxO transcription factor, which can inhibit NF-κB signalling, thereby preventing the synthesis of pro-inflammatory factors(Reference Salminen, Hyttinen and Kaarniranta72). Additionally, Wang et al. demonstrated that AMPK inhibition of NF-κB signalling reduces the expression of various NAD(P)H oxidase subunits, decreasing the production of ROS and thereby alleviating oxidative stress(Reference Wang, Zhang and Liang74). Furthermore, Li et al. indicated that Nrf2 can inhibit NF-κB signalling, suggesting that Nrf2 activators have anti-inflammatory properties(Reference Li, Jia and Zhu75) (Fig. 2).
Figure 2. Effects of AMPK pathway activation on NF-κB and Nrf2 pathways. The colour of the black arrow indicates influence. The colour of the red arrow indicates inhibition, and the colour of the green arrow indicates activation. AMPK, AMP-activated protein kinase; Nrf2, nuclear-related factor 2.
These interactions have been corroborated by other researchers. For instance, Li et al. conducted an experiment in which male mice were administered an extract containing cyanidin-3-arabinoside, cyanidin-3-glucoside and cyanidin-3-galactoside at a dosage of 50 mg/g body weight. These anthocyanins are potent antioxidants capable of neutralising ROS, thereby mitigating oxidative stress, which is frequently associated with chronic inflammation. The authors demonstrated a significant reduction in the levels of IL-1β, TNF-α and IL-6, indicating a suppression of the inflammatory response. The study further elucidated that the production of pro-inflammatory cytokines, particularly TNF-α and IL-1β, is mediated by the transcription factor NF-κB, which is activated through toll-like receptor signalling. Activation of toll-like receptor 4 is positively correlated with inducible nitric oxide synthase, thereby linking inflammation and oxidative stress (Table 4)(Reference Li, Li and Xu24). This is also confirmed by Wang et al. who indicated that it is ROS that activates T lymphocytes, which release inflammatory factors (Table 4)(Reference Wang, Liu and Zhao71). Furthermore, Ohgami et al. also indicate that it is the antioxidant effect of chokeberries that is responsible for inflammatory responses. The authors confirm this with a reduction in nitric oxide production, which led to the inhibition of nitric oxide synthase and, consequently, a reduction in the inflammatory cytokine TNF-α. In addition, the researchers emphasise that, first, the anti-inflammatory effect of chokeberry is dose-dependent. Second, the authors point out that the anti-inflammatory mechanism of anthocyanin compounds consists of several factors. Ohgami et al. explain that one of the anti-inflammatory mechanisms of chokeberry is the blocking of cyclooxygenase-2 protein expression. Cyclooxygenase-2 is primarily responsible for increased PGE2 production during inflammation, and PGE2 is generally considered a pro-inflammatory agent (Table 4)(Reference Ohgami, Ilieva and Shiratori44) (Fig. 2).
Only five studies analysing biomarkers of inflammation in humans were included in the systematic review. Skarpańska-Stejnborn et al. reported a statistically significant reduction in TNF-α levels following the administration of 150 ml of chokeberry juice daily for 8 weeks to elite rowers. The authors suggest that anthocyanins in chokeberry juice may attenuate the activity of major inflammatory enzymes and prevent the adhesion of leukocytes to vascular endothelial cells by inactivating TNF-α (Table 5)(Reference Skarpańska-Stejnborn, Basta and Sadowska6).
In contrast, Xie et al. observed no significant changes in inflammatory biomarkers when supplementing 500 mg/d of chokeberry extract for 12 weeks among former smokers. The researchers propose that the anti-inflammatory effects of polyphenols from chokeberry may be more pronounced in populations suffering from chronic inflammation, rather than in relatively healthy individuals (Table 4). This suggests that the efficacy of chokeberry-derived polyphenols might be contingent upon the baseline inflammatory status of the subjects (Table 5)(Reference Xie, Vance and Kim66).
We hypothesise that the administration of black chokeberry exerts a notable impact on inflammation reduction, intricately linked to the mitigation of ROS and subsequent oxidative stress. However, this reduction appears to be observed in increased and chronic inflammation. A clear discrepancy emerges between studies focusing on inflammation reduction and those targeting oxidative stress, with approximately 70 % fewer studies analysing inflammation biomarkers. This underscores the imperative for future experiments to delve deeper into elucidating the trajectory of alterations and the intricacies involved in mitigating the inflammatory process after chokeberry use. Such endeavours are crucial for comprehensively understanding the mechanisms underlying the anti-inflammatory properties of chokeberry and optimising its therapeutic potential in combating inflammatory conditions.
Effect of black chokeberry on intestinal parameters
Diversity and richness are pivotal parameters characterising the human gut microbiota, with implications extending to various health outcomes(Reference Wei, Zhang and Zhang26). Diminished gene diversity and richness within the intestinal microbiome are frequently observed in individuals afflicted with diverse disorders, such as obesity(Reference Cheng, Zhang and Yang76), type 2 diabetes mellitus(Reference Cheng, Zhang and Yang76), psychiatric disorders(Reference Nikolova, Smith and Hall77), Crohn’s disease(Reference Imhann, Vich Vila and Bonder78) or even in infants delivered by caesarean section(Reference Jakobsson, Abrahamsson and Jenmalm79). Clinical interventions (e.g. antibiotics, drug use) and environmental factors (e.g. smoking, diet and physical activity) also affect microbial diversity(Reference Wei, Li, Yan and Sun80).
Supplementation with Aronia melanocarpa has been explored for its potential impact on gut health; however, no effect on α and β diversity has been observed in human studies(Reference Le Sayec, Xu and Laiola12,Reference Istas, Wood, Le Sayec and Rawlings68,Reference Lackner, Mahnert and Moissl-Eichinger70) . In animal research, results were inconclusive. In three studies, parameters remained at the same level(Reference Zhu, Zhang and Wei22,Reference Ren, Fang, Zhang and Wang41,Reference Zhu, Wei and Karras47) , and in three, they increased(Reference Zhao, Liu and Ding20,Reference Liu, Martin and Valdez21,Reference Wilson, Peach and Fausset62) . However, the Firmicutes:Bacteroides ratio tended to lower in animal models(Reference Zhu, Zhang and Wei22,Reference Zhu, Wei and Karras47) . It is a widely accepted marker that has an essential influence on maintaining normal intestinal homeostasis. An increased or decreased Firmicutes:Bacteroides ratio is regarded as dysbiosis, whereby the former is usually observed concerning obesity and the latter to inflammatory bowel disease(Reference Stojanov, Berlec and Štrukelj81). Both studies were carried out on high-fat diet models suggesting a potential trend in reducing the Firmicutes:Bacteroidetes ratio in obesity following Aronia melanocarpa supplementation(Reference Zhu, Zhang and Wei22,Reference Zhu, Wei and Karras47) . Moreover, increases in Bacteroides and Bacteroidetes have been consistently noted across studies(Reference Le Sayec, Xu and Laiola12,Reference Zhao, Liu and Ding20,Reference Zhu, Zhang and Wei22,Reference Ren, Fang, Zhang and Wang41,Reference Zhu, Wei and Karras47,Reference Istas, Wood, Le Sayec and Rawlings68) . Notably, Bacteroides play a crucial role in supplying nutrients to other microbial residents of the gut, thereby contributing to the overall balance and functioning of the gut microbiota. Furthermore, they serve as a protective barrier against pathogens, helping to maintain intestinal homeostasis and prevent infections. This highlights the potential importance of increasing Bacteroides abundance through aronia supplementation to promote gut health and mitigate the risk of various gastrointestinal disorders(Reference Zafar and Saier82).
We also noticed a rise in Verrucomicrobia and Akkermansia muciniphila (Reference Zhu, Zhang and Wei22,Reference Zhu, Wei and Karras47) , which are connected to gut health(Reference Derrien, Belzer and de Vos83) and are even proposed as a next-generation probiotic(Reference Zhai, Feng and Arjan84). Furthermore, levels of Prevotella also increased(Reference Zhu, Zhang and Wei22,Reference Ren, Fang, Zhang and Wang41,Reference Zhu, Wei and Karras47) . The Western lifestyle is causal in the loss of Prevotella diversity, and aronia could reverse this pathway. An increase in Romboutsia was also observed(Reference Zhu, Zhang and Wei22,Reference Ren, Fang, Zhang and Wang41,Reference Zhu, Wei and Karras47) , the bacterium is negatively correlated with body weight, insulin and fasting glucose. In the end, the abundance of pathogens in the gut decreased after aronia supplementation: Proteobacteria, the microbial signature of dysbiosis(Reference Shin, Whon and Bae85), was decreased(Reference Li, Li and Xu24); Escherichia-Shigella associated not only with dysbiosis but also with inflammation was also decreased(Reference Ren, Fang, Zhang and Wang41), Haemophilus parainfluenzae, which may cause infections of soft tissue, central nervous system and endocarditis(Reference Onafowokan, Mateo and Bonatti86), followed the same pattern(Reference Le Sayec, Xu and Laiola12). To summarise, supplementation with Aronia melanocarpa may positively affect gut health, especially by reducing potential pathogens and increasing the abundance of bacteria positively correlated to gut health, such as Akkermansia and Bacteroidetes. In our review, only one study on gut permeability was conducted on growing pigs. Aronia significantly increased the jejunal gene expression of tight junction proteins, such as occludin, claudin and zonulin(Reference Ren, Fang, Zhang and Wang41), thus improving gut barrier tightness. Another study carried out on a rat model of obesity confirmed aronia’s positive impact on gut tightness, but it was not approved for the review process due to the lack of full text(Reference Zhu, Cai and Dai87). Preliminary animal studies may suggest the possibility of chokeberry influencing the tightness of the intestinal barrier.
The compounds found in black chokeberry play a pivotal role in maintaining the overall balance within the system. This is a crucial consideration given the tendency for disturbances in organismal homeostasis to accompany disease processes and various disorders. Chokeberry not only reduces oxidative stress and modulates the inflammatory response but also influences the composition of the intestinal microbiome through the growth of bacteria, which are positively correlated with health. This underscores the potential of natural supplements, like chokeberry in restoring systemic equilibrium, as evidenced by numerous studies highlighting their efficacy across a spectrum of physiological processes. However, it is imperative to acknowledge the significant divergence between findings in human and animal studies. While existing research underscores the potential benefits of chokeberry supplementation, particularly in prophylactic contexts aimed at preserving organism harmony and homeostasis, further investigation is warranted to fully elucidate its mechanisms and optimise its application. Moreover, the substantial gap between studies focusing on oxidative stress, inflammation and intestinal parameters underscores the necessity for additional research to comprehensively understand the effects of chokeberry on inflammation and microbiota alterations. Additionally, the observation of fewer studies involving women compared with men highlights an area requiring considerable attention and clarification. Addressing these research gaps would be pivotal in further understanding the potential benefits and optimal applications of black chokeberry supplementation for promoting overall health and mitigating disease risk across diverse populations.
Limitations
The primary limitation of this review is the considerable heterogeneity in the methodologies of the included studies. Variations in supplementation duration, type of supplement (e.g. extract, juice, fruit), dosage and sample sizes among the studies introduce substantial challenges in result comparison. Additionally, the diversity of study populations and the significant discrepancies between human and animal model studies further complicate the synthesis of findings. A notable concern is the predominance of studies from Eastern countries, which raises questions about the generalizability of the results to Western populations. These factors necessitate a cautious interpretation of the review’s conclusions. Furthermore, despite employing the PRISMA protocol for article selection, there remains a possibility that some relevant manuscripts were inadvertently omitted. Another critical limitation is the presence of significant sources of bias in many of the studies analysed. This is particularly noticeably true for studies on animal models. This may indicate that scientists are still not very familiar with this tool.
Acknowledgements
This research received no specific grant from any funding agency, commercial or not-for-profit sectors.
S. K. and H. Dz.: study design, data collection and writing – original draft preparation. A. K., M. P., H. Dz., S. K.: data analysis. A. S-S., J. O-K: writing – review and editing. All authors have read and approved the final manuscript.
The authors declare no conflict of interest.
Data are available from the corresponding author upon reasonable request.
