THE CHEMISTRY AND ACTION OF 6-ALKYLSALICYLATES OF INDIAN GINKGO-BILOBA

Five 6-alkyl (n-tridecyl-, n-pentadecyl-, n-heptadecyl-, n-pentadeceny l- and n-heptadecenyl-) salicylates 1a-e, in free and conjugated teste rs, phospholipids) forms, constituting one of the largest classes of b ioactive metabolites have been isolated from the leaves and fruits of ten Ginkgo biloba trees of different ages (3-80 years) and indigenous occurrence. These compounds have been characterized by comprehensive c hromatographic-spectroscopic analyses (HPTLC, HPLC, GC-MS, H-1 NMR), c hemical transformation, and by direct comparison of some of them with authentic markers. Selective anti-oxidative (lipoxygenase modulatory), free radical captodative ((OH)-O-0, (SO3-)-S-0), and anti-allergic an d anti-inflammatory screening of the total IGb extract and of 1a-e hav e been conducted. Our findings suggest a significant contribution of t he 6-alkylsalicylates towards the elixir effect of Ginkgo, contrary to an earlier apprehension that ginkgolic acids (equivalent to 6-alkylsa licylates) might cause allergic manifestations in recipients and, ther efore, that they should be removed from Ginkgo formulations.