Inflammation and oxidative stress play crucial roles in the etiology of type 2 diabetes mellitus. In this study, we examined the anti-diabetic effects of triterpenoid saponins extracted from Stauntonia chinensis on stimulating glucose uptake by insulin-resistant human HepG2 cells. The results showed that saponin 6 significantly increased glucose uptake and glucose catabolism. Saponin 6 also enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and activated the insulin receptor (IR)/insulin receptor substrate-1 (IRS-1)/phosphoinositide 3-kinase (PI3K)/Akt pathway. Therefore, our results suggest that saponins from S. chinensis improve glucose uptake and catabolism in hepatic cells by stimulating the AMPK and the IR/IRS-1/PI3K/Akt signaling pathways. The results also imply that saponins from S. chinensis can enhance glucose uptake and insulin sensitivity, representing a promising treatment for type 2 diabetes mellitus.

Stauntonia chinensis DC. has been utilised as a traditional herbal medicine for its anti‐hyperglycemic characteristic, which has been associated with triterpene saponins. The goal of the current evaluation was to examine hypoglycemic activity and affiliated mechanism of total saponins from S. chinensis. The chemical composition was analysed by HPLC‐ESI‐MS/MS. The fasting blood glucose, oral glucose tolerance test, insulin tolerance test, insulin and glycogen levels of type 2 diabetic db/db mice administered total saponins were quantified to determine the hypoglycemic effects. The serum lipid profiles were assessed to determine the hypolipidemic effects. Western blotting was used to quantify the protein levels of insulin receptor substrates (IRS)‐1/PI3K/AKT, AMPK/ACC and GLUT4. Twenty triterpene saponins were identified from the total saponins, which exhibited hypoglycemic activities and modulated hyperlipidemia that was associated with type 2 diabetes. The hypoglycemic effects were partly due to the activation of GLUT4, which is regulated by IRS‐1/PI3K/AKT. The activation of the AMPK/ACC signalling pathway may be responsible for the hypolipidemic activity. This study revealed that total saponins from S. chinensis have significant hypoglycemic and hypolipidemic activity in diabetic db/db mice, indicating that these may be utilised in the development of saponins based on S. chinensis for the treatment of type 2 diabetes.

α-Glucosidase is a promising target for the treatment of obesity and diabetes mellitus. A series of oleanolic acid derivative–chalcone conjugates were designed and synthesized as α-glucosidase inhibitors. Their structures were determined by spectroscopic analysis and their α-glucosidase inhibitory activities were investigated in vitro. Most conjugates exhibited moderate inhibitory activity against α-glucosidase; among them, conjugate 1b (IC₅₀ = 3.2 ± 0.2 μM) possessed the strongest α-glucosidase inhibitory activity, and the preliminary structure–activity relationship showed that the furan or thiophene rings in the chalcone units of the conjugates had a tendency to enhance the activity. Lineweaver–Burk plot analysis demonstrated competitive inhibition of α-glucosidase activity by 1b, 6b, 5c and 4d; their inhibition constant (K_i) values were 16.6, 29.3, 14.6 and 20.6 μM, respectively. The interaction forces between the conjugates and α-glucosidase were hydrogen bonding and van der Waals.

Genistein, a flavonoid, is one of the main components of soybeans. It was shown to alleviate contact dermatitis through the inhibition of the allergen-induced activation of MAP2K2 in keratinocytes.

Two unique carbazole–indole-type dimeric alkaloids, glycosmisines A (1) and B (2), have been isolated from the stems of Glycosmis pentaphylla and their structures are elucidated by 1D and 2D NMR analyses, and their cytotoxicity against the growth of three cancer cell lines (A549, HepG-2 and Huh-7 cells) in culture was investigated using an MTT assay. Compounds 1 and 2 exhibited significant levels of cytotoxicity against three human cancer cell lines, and these two compounds also induced apoptosis in the same cell lines, as evidenced by changes in the morphological features of cells treated with these compounds and their dose-dependent accumulation of a sub-G1 population.