Protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase inhibitory activities of Schisandra chinensis (Turcz.) Baill

Schisandra chinensis (Turcz.) Baill. (SCTB) is a functional, economical and medicinal herb that has numerous medicinal and nutritional properties. The present study was carried out to investigate its inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) and alpha-glucosidase. The extracts and compounds isolated from petroleum ether (PE) extract were further tested for their PTP1B and alpha-glucosidase inhibitory activities. The data showed that the anti-diabetic activity of SCTB is attributable to the PE (IC50 = 1.77 +/- 0.20 mu g/mL) and EtOAc (IC50 = 1.04 +/- 0.20 mu g/mL) extracts as well as compounds 1 (IC50 = 2.36 +/- 0.20 mu M) and 4 (IC50 = 9.78 +/- 0.10 mu M) that were compared with the positive controls NaVO4 (IC50 = 22 +/- 0.20 mu M) and acarbose (IC50 = 2.10 +/- 0.10 mu g/mL), respectively. These results demonstrate that the stems of SCTB are useful as potential functional food ingredients for the prevention and treatment of type-2 diabetes. (C) 2014 Published by Elsevier Ltd.