Antidiabetic Effect of <scp>S</scp>chisandrae <scp>C</scp>hinensis <scp>F</scp>ructus Involves Inhibition of the Sodium Glucose Cotransporter

Abstract

Abstract Preclinical Research S chisandrae C hinensis F ructus ( SCF ), the fruit of S chisandra chinensis ( T urcz.) B aill. (family S chisandraceae ) is traditionally used as a tonic and antidiabetic agent in A sia. In this study, SCF was investigated for its effects on sodium glucose cotransporters 1 and 2 ( SGLT 1 and 2) expressed in a COS ‐7 cell line for its specificity in inhibiting SGLT2 , which is a novel mechanism to screen for potential antidiabetic agents. Using a bioassay‐guided fractionation, we then tried to isolate and identify the active fraction(s)/component(s). The ethanol extract of SCF at a concentration of 1 mg/mL significantly inhibited 89% of SGLT1 and 73% of SGLT2 activities in a [ 14 C ]‐α‐methyl‐d‐glucopyranoside ([ 14 C ]‐ AMG ) uptake assay. Fractionation of the ethanol extract yielded nine fractions, of which F8 , at a concentration of 1 mg/mL, was specific in inhibiting SGLT 2 (42% inhibition, P &lt; 0.001), without inhibiting SGLT 1. Using LC / MS ‐ MS , three compounds, deoxyschisandrin, schisandrin B (γ‐schisandrin) and schisandrin were identified in F8 and their amounts quantified. However, subsequent evaluation in the [ 14 C ]‐ AMG uptake assay showed that these three compounds failed to inhibit SGLT 2 activity indicating that the SGLT active component(s) from SCF have yet to be identified. Drug Dev Res 76 : 1–8, 2015