Sodium alginate derived from seaweed has demonstrated pancreatic lipase inhibition in vitro ⁽Reference Wilcox, Bownlee and Richardson¹⁾, and other seaweed extracts containing bioactive compounds have also shown a reduction in digestive enzyme activity⁽Reference Balasubramaniam, Mustar and Mustafa Khalid²⁾. Four extracts, containing biopolymers of Fucus vesiculosus were analysed for their potential to inhibit pancreatic lipase using modified turbidimetric methodology⁽Reference Vogel and Zieve³⁾ and an olive oil substrate. Inhibition of pancreatic lipase prevents triacylglycerol breakdown, potentially reducing dietary fat digestion in vivo. All extracts demonstrated significant inhibition. 100% lipase inhibition was observed with 5 mg/ml and 2·5 mg/ml supernatant extract, and 5 mg/ml homogenate extract (P < 0·0001; data not shown). Dose-response data indicated potency, whereby: homogenate > supernatant > alginate > pellet (data not shown).

The most potent extracts were analysed in a model gut system, using olive oil. The inhibitory potential of extracts was assessed during salivary, gastric and small intestinal phases of digestion. The homogenate extract reduced fat digestion significantly, to 62·4% of the substrate control after 150 minutes (Fig 1; P < 0·0001), while the ethanol supernatant reduced fat digestion significantly, to 24·3% of the substrate control after 120 minutes (Fig 1; P < 0·001).

Fig. 1. Free glycerol concentration during gastric and small intestinal phases of the gut model.

Given the inhibition of pancreatic lipase observed in vitro, and the nutritional value of Fucus vesiculosus, seaweed extracts are potential functional food ingredients, and may also be used concomitantly with the weight control drug Orlistat.