Inhibition of rat adjuvant-induced arthritis by ginkgetin, a biflavone from Ginkgo biloba leaves

Ginkgetin, a biflavone isolated from Ginkgo biloba leaves, was previously r eported as an inhibitor of group II phospholipase A(2). In this study, gink getin was evaluated for in vivo antiarthritic and analgesic activities. Gin kgetin (10-20 mg/kg/ day) strongly reduced arthritic inflammation in an ani mal model of rat adjuvant-induced arthritis (86 % inhibition at 16 days at a dose of 20 mg/kg/day) via intraperitoneal injection, while prednisolone ( 5 mg/kg/day) showed 79 % reduction. Histological examination of the knee jo ints confirmed our findings. When analgesic activity was measured, ginkgeti n showed a dose-dependent inhibition in an animal model of acetic acid-indu ced writhing. ED50 values for ginkgetin and indomethacin were 8.9 and 3.8 m g/kg, respectively. All these results indicate that ginkgetin may be a pote ntial antiarthritic agent having analgesic activity.