Galantamine (GAL), a morphine-like alkaloid produced by some members of the Amaryllidaceae plant family, is a possible therapeutic agent in Alzheimer's disease because of its central cholinergic effects. GAL has been extracted from the plant sources or produced synthetically for pharmaceutical use. Limited supply of the natural source and high cost of synthetic production has led to a search for alternative sources of this valuable compound. In the present study, a total of six Galanthus nivalis populations (GNPs) and 11 Narcissus tazetta populations (NTPs) were collected across different regions of Iran and were then subjected to the high-performance liquid chromatography analysis for their GAL quantification. The GAL content ranged from 0.05 to 0.36 mg/g dry weight (DW) in the bulbs of GNPs, and from 0.03 to 0.33 mg/g DW in the bulbs of NTPs. Maximum content of GAL (0.36 and 0.33 mg/g DW) was measured in the Zirab population of G. nivalis and Ghaemshahr population of N. tazetta, respectively. Our results provided a suitable material for further agronomical and biotechnological strategies for enhanced production of valuable GAL compound on a large scale.

Across host–parasite systems, there is evidence that pesticide exposure increases parasite loads and mortality following infection. However, whether these effects are driven by reductions in host resistance to infection or slower rates of parasite clearance is often unclear. Using controlled laboratory experiments, we examined the ability of larval northern leopard frogs (Lithobates pipiens) and American toads (Anaxyrus americanus) to resist and clear trematode (Echinoparyphium sp.) infections following exposure to the insecticide carbaryl. Northern leopard frogs exposed to 1 mg L−1 of carbaryl had 61% higher parasite loads compared with unexposed individuals, while there was no immediate effect of carbaryl on parasite encystment in American toads. However, when tadpoles were exposed to carbaryl and moved to freshwater for 14 days before the parasite challenge, we recovered 37 and 63% more parasites from carbaryl-exposed northern leopard frogs and American toads, respectively, compared with the control. No effects on clearance were found for either species. Collectively, our results suggest that pesticide exposure can reduce the ability of amphibians to resist parasite infections and that these effects can persist weeks following exposure. It is critical for researchers to incorporate species interactions into toxicity studies to improve our understanding of how contaminants affect ecological communities.

The acetylcholinesterase (AChE) inhibitor donepezil is also a σ1 receptor agonist. We examined whether donepezil binds to σ1 receptors in the living human brain after a single oral administration. Dynamic positron emission tomography (PET) data acquisition using the selective σ1 receptor ligand [11C]SA4503 was performed to evaluate quantitatively the binding of [11C]SA4503 to σ1 receptors in eight healthy male volunteers. Each subject had a PET scan before and after receiving a single dose of donepezil (5 or 10 mg). The binding potential of [11C]SA4503 was calculated. Doses of 5 mg and 10 mg donepezil bound to σ1 receptors in the human brain with occupancies of ~60% and ~75%, respectively, in a dose-dependent manner. This study demonstrated that donepezil binds to σ1 receptors in the living human brain at therapeutic doses. Therefore, σ1 receptors may be implicated in the pharmacological mechanism of donepezil in the human brain.