Effect of kaikasaponin III obtained from Pueraria thunbergiana flowers on serum and hepatic lipid peroxides and tissue factor activity in the streptozotocin-induced diabetic rat.

We investigated the effect of kaikasaponin III (KS-III) on Phase I and II enzymes and tissue factor (TF) activity to elucidate the pharmacological actions of this immunosuppressive saponin in the diabetic rat. This compound was obtained from the flower of Pueraria thunbergiana (Leguminosae) by chromatographic isolation. This crude drug (Puerariae Flos) has been used as a therapeutic agent for diabetes mellitus in traditional Korean medicine. KS-III prolonged the bleeding time and plasma clotting time in streptozotocin (STZ)-treated rats and increased the TF activity, suggesting that this compound has anti-thrombosis activity in STZ-induced rats. It also inhibited the formation of malondialdehyde (MDA) and hydroxy radicals in serum and liver, but promoted superoxide dismutase (SOD) activity. Low MDA concentrations and low xanthine oxidase and aldehyde oxidase activities were observed in the KS-III-treated rats, suggesting that such Phase I enzyme activities are the major source of lipid peroxidation. However, KS-III increased Phase II enzyme activities such as SOD, glutathione peroxidase, and catalase, suggesting the activation of free radical-scavenging enzymes. These results suggest that KS-III may exhibit its hypoglycemic and hypolipidemic effects by up-regulating or down-regulating antioxidant mechanisms via the changes in Phase I and II enzyme activities.