Effect of Ginkgo biloba Linn. Leaf Extract on Peripheral Blood Flow and Bleeding Time

Abstract

The effect of repeated oral administration of Ginkgo biloba leaf extract on peripheral blood flow and bleeding time was studied in male Wistar rats. The extract at various doses (12.5, 25 and 50 mg/kg/day) or pentoxifylline (200 mg/kg/day) was administered to animals for 12 weeks. Plantar blood flow was measured before the start of the experiment (week 0) and then 4, 8 and 12 weeks after the extract or drug administration. At the end of the experiment, bleeding time of animal in each group was also determined.

The results showed that plantar blood flow increased dose dependently in all groups treated with the extract but not in that treated with pentoxifylline. Plantar blood flow in a group receiving a medium dose extract increased by 52% (P<0.05) at 12 week after the administration. The increase was observed earlier in a group receiving a high dose and the increase continued throughout the experiment with a maximal increase at week 12 was 73% (P<0.05). Bleeding time of rats receiving a high dose extract was longer than that of the control (P<0.05). The present study suggests that people who take Ginkgo biloba L. leaf extract as an alternative treatment should be aware that any disorder in bleeding time might occur if the treatment is applied for a long period.