Activity of an antimicrobial compound isolated from Ginkgo biloba

Ginkgo biloba is among the most sold medicinal plants of this world with estimates of sales in the USA of more than $249 million (de Kosky et al., 2008). Most of the sales are of special extracts from the leaves and are mainly used for the improvement of peripheral and central blood circulation (DeFeudis, 1998). Important constituents present in the leaves are terpene trilactones, i.e., ginkgolides (A, B, C, J) and bilobalide, many flavonol glycosides, biflavones, proanthocyanidins, alkylphenols, simple phenolic acids, 6-hydroxykynurenic acid, 4-Omethylpyridoxine and polyprenols (van Beek, 2002). Egb761 is the first standardised preparation patented by Schwabe (1994) for medicinal use. The content of ginkgolic acids (alkylphenol) in this preparation should not exceed 5ppm because of suspected cytotoxic and allergenic properties (Pan, 2007).