Am J Contact Dermat. 1998 Sep; 9(3): 146-8.
The sensitizing capacity of ginkgolic acids in guinea pigs.
Dermatology Center, Buxtehude, Germany.
BACKGROUND: Ginkgo biloba possesses fruits that have caused numerous cases of allergic contact dermatitis. Low amounts of the ginkgolic acids occur in the leaves as well. OBJECTIVE: Leaf extracts are used to treat cerebrovascular and peripheral vascular disorders. The question arises whether skin hypersensitivity reactions may be adverse effects because the pharmaceutical preparations contain low amounts of ginkgolic acids. METHODS: Guinea pigs were sensitized experimentally with pure ginkgolic acids as well as with leaf extracts containing approximately 1,000 ppm of ginkgolic acids. RESULTS: The guinea pigs could be sensitized successfully with the pure ginkgolic acids. The animals could not be sensitized with the leaf extract. CONCLUSION: Leaf extracts of Ginkgo biloba taken orally or given by infusion to treat diffuse cerebral disturbances can be considered safe, even when they might contain up to 1,000 ppm of the sensitizing ginkgolic acids.