Barley ß-glucan inhibits digestion of soybean oil in vitro and lipid-lowering effects of digested products in cell co-culture model.

The effect of barley ß-glucan on soybean oil digestion characteristics before and after fermentation was studied in an in vitro-simulated gastrointestinal digestion model. The addition of barley ß-glucan made the system more unstable, the particle size increased significantly, and confocal laser imaging showed that it was easier to form agglomerates. The addition of barley ß-glucan increased the proportion of unsaturated fatty acids in digestion products, and reduced digestibility of soybean oil. In a co-culture model of Caco-2/HT29 and HepG2 cells, the effects of digestive products of soybean oil and barley ß-glucan before and after fermentation on lipid metabolism in HepG2 cells were investigated. The results showed that adding only soybean oil digestion products significantly increased triglycerides (TG) content and lipid accumulation in basolateral HepG2 cells. When fermented barley ß-glucan was added, lipid deposition was significantly decreased, and the lipid-lowering activity was better than that of unfermented barley ß-glucan.

Saponins from bitter melon reduce lipid accumulation via induction of autophagy in C. elegans and HepG2 cell line.

Saponins from bitter melon (BMS) are well-known to have various biological activities, especially in the field of fat-lowering. However, many gaps remain in our knowledge of BMS-induced fat reduction and health benefits. Here, we aimed to investigate the precise mechanism of BMS in alleviating fat accumulation in C. elegans and HepG2 cell line. Results indicated that BMS showed strong fat-lowering and lifespan-extension properties. Lipidomic analysis illustrated that BMS could alter the lipid profile, especially represented by phosphatidylethanolamine (PE) increase, which plays an essential role in autophagy. Furthermore, we applied gene-deficient mutants and RNAi technology to confirm that BMS largely depended on daf-16/FoxO1 and hlh-30/TFEB mediated lipophagy to reduce fat deposition. In addition, BMS could ameliorate oil acid (OA)-induced fat accumulation in HepG2 cells by induction of autophagy-related proteins, such as the phosphorylated AMPK and LC3B. In conclusion, our results elucidated the underlying mechanism of bitter melon saponins interfering with lipid metabolism from the autophagy point of view, which provide new insights into a nutraceutical to mitigate obesity.