Abstract:Microwave-assisted extraction, organic solvent extraction, macroporous resin chromatography, preparative chromatography, and high-performance liquid chromatography (HPLC) were used to isolate, purify, and identify active ingredients from Cornus officinalis. Two main types of iridoid glycosides-loganin and morroniside-were isolated, and the fraction eluted using n-butanol 30% ethanol (Fr. Bu-2) was used to investigate the effects of loganin and morroniside on glucose uptake (GU) by HepG2 cells and a HepG2 cell insulin resistance model; their cytotoxic effects on HepG2 cells were also assessed. The results showed that loganin and morroniside had no significant effect on cell proliferation. Fr. Bu-2, loganin, and morroniside could significantly promote GU by HepG2 cells. Among them, loganin exhibited the strongest promotion effect in a dose-dependent manner. The GU with 0.5 mg/mL loganin and morroniside was about 3.24 and 1.64 times that of the control group, respectively. Moreover, high concentrations (>0.1 mg/mL) of Fr. Bu-2, loganin, and morroniside could significantly promote GU by HepG2 insulin resistance model cells, especially loganin. The GU with 0.5 mg/mL loganin and morroniside was about 1.76 and 1.27 times that of the control group, respectively. In summary, Fr. Bu-2, loganin, and morroniside can exert a hypoglycemic effect by promoting GU by HepG2 cells and their insulin resistance model.
