Saponin‐enriched extracts from body wall and Cuvierian tubule of Holothuria leucospilota reduce fat accumulation and suppress lipogenesis in Caenorhabditis elegans

Abstract BACKGROUND Saponins have been shown to possess many pharmacological properties, including altered fat metabolism. The black sea cucumber, Holothuria leucospilota , is a marine animal that contains a specialized organ called a Cuvierian tubule that produces and secrete the bioactive saponins into the tubules and body wall. Therefore, the aims of this study are to investigate the anti‐obesity effect of saponins extracted from body wall and Cuvierian tubules of H. leucospilota . RESULTS The butanol extracts of H. leucospilota body wall and Cuvierian tubules containing high amounts of saponins significantly reduced fat deposition and triglyceride levels in Caenorhabditis elegans fed with 50 mmol L −1 glucose. Moreover, the saponin‐enriched extracts of H. leucospilota significantly restored the lifespan of 2% glucose‐fed worms (18.71%). Green fluorescence protein‐labeled sbp‐1 gene expression and nuclear translocation of daf‐16 were also significantly decreased in H. leucospilota treatment. The saponin‐enriched extracts downregulated the messenger RNA expressions of genes involved in fat storage and metabolism, including sbp‐1 , cebp , and daf‐16 but upregulated the expression of nhr‐49 gene. CONCLUSION Our results suggest that H. leucospilota‐ derived saponins may mediate the reduction of glucose‐induced fat accumulation through sbp‐1 , cebp , daf‐16 and nhr‐9 pathways. Therefore, the H. leucospilota extracts could be used as nutraceuticals for anti‐obesity prevention. © 2019 Society of Chemical Industry