Target screening and antihyperglycemic activity on SGLT2 and α-glucosidase in vitro and in vivo of TSG from Polygonum multiflorum / 中草药

ABSTRACT

Objective: To study the mechanism that TSG can reduce plasma glucose level by inhibiting sodium-dependent glucose cotransporters 2 (SGLT2) and α-glucosidase in vitro and in vivo. Methods: Molecular docking method was used to study the binding affinities of TSG and diabetes related targets. The structures of targets were taken from Protein Data Bank or references. 1-NBDG and PNPG were used as the substrates for the inhibition assays of TSG against SGLT2 and α-glucosidase respectively in vitro. The antihyperglycemic activity of TSG was operated by oral glucose tolerance test (OGTT) and urinary glucose excretion (UGE) test in rats. Results: TSG was identified as the inhibitors of SGLT2 with the docking score of -9.35 less than -9.79 of dapagliflozin as the positive control and α-glucosidase with the docking score of -5.44 compared to -5.58 of acarbose as the positive control. TSG showed the inhibitory rate of 21.6% at the dose of 10 μmol/L against SGLT2 and 32.5% at the dose of 100 μmol/L in vitro test. Compared with model group, the group of 120 mg/kg dose had significant difference (P < 0.05) but the overall effect was not as strong as dapagliflozin in OGTT and UGE test. The result of rat in vivo test showed that glucose inhibition rate of TSG (120 mg/kg) was (9.3 ± 1.0)%, urinary glucose content was (435.5 ± 84.0) mg/kg, which showed certain hypoglycemic effect. Conclusion: TSG exhibited antiglycemic activity through inhibiting SGLT2 and α-glucosidase, which was considered to be a new lead compound of dual target inhibitors.