Determination of Lovastatin, ß-glucan, Total Polyphenols, and Antioxidant Activity in Raw and Processed Oyster Culinary-Medicinal Mushroom, Pleurotus ostreatus (Higher Basidiomycetes).

The objective of this study was to quantify a number of bioactive compounds and antioxidant activity of the oyster mushroom, Pleurotus. Ostreatus, and characterize the effects of processing, such as blanching, on these outcomes. Dry matter content was 8%. Lovastatin was not detected in this study. ß-glucan content of 23.9% and total polyphenol content of 487.12 mg gallic acid equivalent/100 g of dry matter were obtained in raw P. ostreatus. Antioxidant activities as evaluated by 1,1-diphenyl-2-picrylhydrazyl, Trolox equivalent antioxidant capacity, and ferric reducing antioxidant power assays in raw P. ostreatus were 14.46, 16.51, and 11.21 µmol/g, respectively. Blanching did not significantly affect ß-glucan content but caused significant decrease in dry matter content, polyphenol content, and antioxidant activities. Mushroom rolls produced from blanched mushrooms and blanching water contained significantly higher amounts of ß-glucan, total polyphenol content, and FRAP antioxidant activity compared to blanched mushrooms. In conclusion, P. ostreatus is a good source for ß-glucan, dietary polyphenols, and antioxidants. Although the blanching process could affect these properties, re-addition of the blanching water during the production process of mushroom rolls could potentially recover these properties and is therefore recommended.

Short-chain fatty acids stimulate glucagon-like peptide-1 secretion via the G-protein-coupled receptor FFAR2.

Interest in how the gut microbiome can influence the metabolic state of the host has recently heightened. One postulated link is bacterial fermentation of "indigestible" prebiotics to short-chain fatty acids (SCFAs), which in turn modulate the release of gut hormones controlling insulin release and appetite. We show here that SCFAs trigger secretion of the incretin hormone glucagon-like peptide (GLP)-1 from mixed colonic cultures in vitro. Quantitative PCR revealed enriched expression of the SCFA receptors ffar2 (grp43) and ffar3 (gpr41) in GLP-1-secreting L cells, and consistent with the reported coupling of GPR43 to Gq signaling pathways, SCFAs raised cytosolic Ca2+ in L cells in primary culture. Mice lacking ffar2 or ffar3 exhibited reduced SCFA-triggered GLP-1 secretion in vitro and in vivo and a parallel impairment of glucose tolerance. These results highlight SCFAs and their receptors as potential targets for the treatment of diabetes.