Objective: To study the inhibition of glutathione-s-transferase by total saponins of Panax notoginseng and its kinetics analysis in liver of mice.
Method: Mouse liver cytochyma enzyme was obtained by different velocity centrifugation, the mouse liver glutathione-S-transferase of michaelis constant (Km), maximum velocity (Vmax) and the inhibition of glutathione-S-transferase by total saponins of P. notoginseng of 50% inhibiting concentration (IC50), inhibition constant (KI, KIS), the type of inhibition were calculation by Lineweaver-Burk and the low of semi-effet-probit.
Result: It was found that total saponins of P. notoginseng inhibited the glutathione-S-transferase activity with IC50 of 189.54 mg x L(-1). Kinetics analysis showed the glutathione-S-transferase of Km was 0.4563 mmol x L(-1) and Vmax was 476.19 U x mg(-1) with reduced glutathione (GSH) substrate, 0.1097 mmol x L(-1) (Km) and 400.00 U x mg(-1) (Vmax) with 1-chloro-2,4-dinitrobenzene (CDNB) substrate. Kinetics studies of total saponins of P. notoginseng on glutathione-S-transferase showed the inhibition were belong to mix-type with GSH and CDNB; the inhibition constant was 0.27 mg x L(-1) (KI), 0.68 mg x L(-1) (KIS) with GSH, and 0.21 mg x L(-1) (KI), 0.66 mg x L(-1) (KIS) with CDNB.
Conclusion: Total saponins of P. notoginseng strongly inhibited the glutathione-S-transferase activity.