New limonoid orthoacetates and antiprotozoal compounds from Pseudocedrela kotschyi (Schweinf.) Harms

In the course of an antiprotozoal screening of extracts issued from plant species commonly used in the Malian traditional medicine, the dicholoromethane extract of Pseudocedrela kotschyi (Meliaceae) demonstrated a marked activity against the intracellular form of Leishmania major. P. kotschyi is commonly used in the Sub-Saharan region to treat various skin affections, yaws, syphilis chancres, sleeping sickness and treat malaria. Its phytochemical investigation permitted to isolate three novel phragmalin-type limonoid orthoacetates named kotschyin A-C (1-3) besides the known compounds 7-deacetylgedunin, 7-deacetyl-7-oxogedunin [1] (-)-catechin, and (-)-epicatechin. The relative configurations of kotschyin A-C were assigned on the base of NOE correlations. The extract and some pure compounds have then been tested for their cytotoxicity and antiparasitic activity against Leishmania donovani, Trypanosoma brucei rhodesiense, Trypanosoma cruzi, and Plasmodium falciparum. The raw extract exhibited good antiplasmodial, antileishamanial and trypannocidal activities that could be attributed to 7-deacetylgedunin and 7-deacetyl-7-oxogedunin. Kotschyin A-C remained inactive in the same assays.

Reference: 1. MacKinnon, S., Durst, T. et al. (1997), J. Nat. Prod. 60: 336–341.