The inhibitory effects of an eight-herb formula (RCM-107) on pancreatic lipase: enzymatic, HPTLC profiling and in silico approaches

AIMS: Obesity is a global, public health issue that causes or exacerbates serious medical disorders. Chinese herbal therapies have become one of the most popular alternatives due to intolerances of current anti-obesity treatments. The RCM-107 formula (granule) is modified from our previous studied RCM-104 formula, which has demonstrated significant effects on weight reduction in randomized clinical trials. Up to date, there is no published scientific evidence to evaluate the effect of this formula on the weight-loss target pancreatic lipase and therefore, the aim of this study is to investigate the inhibitory effect of RCM-107 and respective individual ingredient on the pancreatic lipase activities. MAIN METHODS: Fluorometric based enzymatic assays, high-performance thin-layer chromatography (HPTLC) profiling and in silico molecular docking techniques were used to investigate the lipase inhibitory effects of the RCM-107 herbal formula and its respective individual herbs. PRINCIPLE FINDINGS: The results demonstrated the potent lipase suppressing effect of the RCM-107 formula. The majority of the ingredients from this formula also showed pancreatic lipase inhibitory activities. The presence of the known weight-loss compounds such as (-)-epigallocatechin-3-gallate (EGCG), epicatechin-3-gallate (ECG), (-)-epicatechin (EC), rutin, crocin and caffeine were identified in the RCM-107 and related single herbs using HPTLC profiling approaches. In addition, EGCG, EC and the known lipase antagonist orlistat acted on the same site. These compounds form hydrogen bonds with corresponding residues HIS152, ASP80 and GLY77, which can be considered as markers of important areas in the ligand-binding site. This may explain the details of their roles in inhibiting pancreatic lipase activities. CONCLUSION: Our data has provided new knowledge to the mechanistic properties of the RCM-107 formula and its respective individual herbal ingredients for weight loss, in terms of reducing lipid absorption via the inhibition of pancreatic lipase.