ABSTRACT
Laboratory of Organic Chemistry, Phytochemical Section, Wageningen Agricultural University, Dreijenplein 8, 6703 HB
Wageningen, The Netherlands
INTRODUCTION
Among the most important and characteristic constituents of the tree Ginkgo biloba is a small group of five compounds collectively indicated with the name “ginkgolides”. The structures of four of these diterpenoids (ginkgolides A, B, C and M) were independently elucidated in the sixties by two Japanese groups (Maruyama et al., 1967; Okabe et al., 1967). In 1987 one more representative (ginkgolide J) was identified. Their structures and that of a closely related sesquiterpene trilactone, named bilobalide, are given below. In the remainder of this chapter their names will abbreviated to G-A, G-B, GC, G-M, G-J and BB. For more than 15 years these compounds were considered to be devoid of any clear pharmacological activity or toxicity. However research carried out in the mid eighties showed that they were potent and selective antagonists of platelet activating factor (PAF) which fact greatly stimulated the interest in these remarkable compounds. Now they are considered to be at least partially responsible for the beneficial activity of Ginkgo phytopharmaceuticals.
