Antihyperglycemic activity of Selaginella tamariscina (Beauv.) Spring

Aim of the studyThe present study was designed to investigate the effects of the EtOH and H2O extracts of Selaginella tamariscina (Beauv.) Spring on hyperglycemia in diabetic rats and HepG2 cells, and to confirm the active fractions of EtOH extract in HepG2 cells.Materials and methodsHepG2 cells and type II diabetic rats induced by low-dose streptozotocin (STZ) and high-fat diet (HFD) were used to evaluate the hypoglycemic effect of EtOH and H2O extracts of Selaginella tamariscina. HepG2 cells were used to evaluate the promotive effect of different fractions of EtOH extract obtained from a polyamide column on glucose utilization.ResultsThe results in HepG2 cells indicated that the EtOH extract had a better hypoglycemic effect than the H2O extract. The results in diabetic rats indicated that both EtOH extract and H2O extract were able to ameliorate the fasting blood glucose (FBG) level and improve oral glucose tolerance (OGTT). Total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-c), free fatty acids (FFA), tumor necrosis factor-α (TNF-α), alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN) and malondialdehyde (MDA) levels in serum were lowered. High density lipoprotein (HDL-c), insulin and superoxide dismutase (SOD) levels in serum were elevated as well as the hepatic glycogen content in diabetic rats. Compared with H2O extract, the effects of EtOH extract were more marked. The 80% ethanol fraction exhibited a stronger hypoglycemic effect than the aqueous and 50% ethanol fractions, but the 95% ethanol fraction did not show any appreciable effects in HepG2 cells.ConclusionsThe results suggested that the EtOH extract had a better hypoglycemic effect than the H2O extract; the 80% ethanol fraction from polyamide column had a strong hypoglycemic activity in HepG2 cells.

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