Tectorigenin and kaikasaponin III from the flowers of Pueraria thunbergiana showed potent hypoglycemic and hypolipidemic effects in the streptozotocin-induced diabetic rats. Intraperitoneal administration of these two compounds with 5 and 10 mg/kg, respectively, for seven days to streptozotocin-induced rats significantly reduced the blood glucose, total cholesterol, LDL- and VLDL-cholesterol and triglyceride levels when compared with those of control group. Glycitein in which 5-OH is unlinked and tectoridin (7-O-glycoside of tectorigenin) isolated from the flowers of P. thunbergiana did not improve hyperglycemia and hyperlipidemia. In addition, tectorigenin showed in vitro antioxidant effects on 1,1diphenyl-2-pirylhydrazyl (DPPH) radical, xanthine-xanthine oxidase superoxide anion radical, and lipid peroxidation in rat microsomes induced by enzymatic and non-enzymatic methods. We further found that tectorigenin and kaikasaponin III protected the Vero cell line (normal monkey kidney) from injury by hydrogen peroxide. From these findings, it seems likely that the antioxidant action of tectorigenin and kaikasaponin III may alleviate the streptozotocin-induced toxicity and contribute to hypoglycemic and hypolipidemic effects.

In a course of obtaining more amount of bioactive costunolide and successive phytochemical isolation from Magnolia sieboldii (Magnoliaceae), a novel acyclic monoterpene 1 named deoxygeraniol [2,6(E)-dimethyl-2,6-octadiene] was isolated along with beta-sitosterol 3-O-linoleate (2), trilinolein (3) and high amount of costunolide (4) in the pure state. The structure of compound 1 was determined on the basis of spectroscopic data. Costunolide was found to induce apoptotic cell death in a dose-dependent manner by nucleosomal DNA ladder and flow cytometric analysis. Immunoblot analysis showed that the level of the anti-apoptotic protein, Bcl-2, was decreased, whereas the cleavage of poly-(ADP-ribose) polymerase was activated. Furthermore, the N-acetyl-L-cysteine antioxidant effectively prevented costunolide-induced cytotoxicity. These results suggest that costunolide-induced cell death is mediated by reactive oxygen species

From the leaves of Ligularia fischeri var. spiciformis, a new eremophilanolide, 8 alpha-methoxy-6-oxoeremophil-7(11)-en-12,8-olide (6-oxoeremophilenolide) and a eudesmane-type sesquiterpene, (+)-intermedeol were isolated. The structures were determined on the basis of 2D-NMR spectral data. Data on cytotoxicity showed that the latter was clearly more potent than the former compound.