Chemistry and biology of alkylphenols from Ginkgo biloba L

Ginkgolic acid and related alkylphenols constitute major components of the lipid fraction of the fruit pods of Ginkgo biloba L. In addition, this class of substances is present in Ginkgo leaves which are widely used to prepare extracts for the treatment of peripheral or cerebral circulatory disorders, as well as vascular and Alzheimer type dementia. The present paper reviews the literature on chemical and biological aspects of alkylphenols from Ginkgo with special reference to their allergic and other undesired properties. As these compounds are present in crude leaf extracts, their completest possible removal has therefore to be guaranteed for therapeutically used extracts by the production process. Technically this does not imply any problem and most preparations available on the market fulfil the requirements of the Monograph of the Commission E of the former Federal German Health Authority (Bundesgesundheitsamt, BGA) requesting a maximal concentration of 5 ppm ginkgolic acids.