Comparative analysis of pharmaceuticals and dietary supplements containing extracts from the leaves of Ginkgo biloba L.

Abstract: Chromatography (TLC and HPLC) tests were performed of 11 preparations containing dry extract of Ginkgo biloba leaves: three pharmaceuticals (preparations 1, 3 and 5) and eight dietary supplements (preparations 2, 4, 6-11), and dry extract of Ginkgo biloba leaves (preparation 12) as a standard certified for compliance with Eur. Ph. 6.1. and FP VIII (1, 2). Preparations registered in Poland as pharmaceuticals contained the major active ingredients (flavonoids and terpene lactones) in amount declared by their producers (and consistent with pharmacopoeial requirements) and acceptable level of potentially toxic ginkgolic acids (below 5 ppm). The concentration of active compounds in dietary supplements was varied. Some of them satisfied applicable quality criteria (mainly preparation 8), however, the majority had reduced levels of therapeutic compounds (4, 6, 7, 11) and increased concentration of ginkgolic acids (4, 9, 10, 11).