Biologically active triterpenoids of biogenetic interest from the fresh fruit coats of Azadirachta indica

Two new triterpenoids of biogenetic interest, namely, 26,27-dinor-17-oxa-1, 14,20(22)-trien-3, 16-dioxo-7 alpha-acetoxy-17 beta-methoxy-4,4,8-trimethy l(5 alpha, 13 alpha)-cholane (meliacinin) 1 and 24,25,26,27-tetranor-apotir ucalla(-apoeupha)-7 alpha-acetoxy-1,14,20(22)-trien-3-oxo-23-oic acid (azad ironic acid) 2 have been isolated from the fresh fruit coats of Azadirachta indica. Their structures were established through comparative spectral stu dies. 1 is the first dinorapoeuphane with seco ring D of deoxygedunin type and 2 is the first tetranorapoeuphane with an open side chain representing a biogenetic intermediate between the intact triterpenoids and meliacins. B oth 1 and 2 showed toxicity against mosquito (Anopheles stephensi) with LC5 0 13 and 4.5 ppm, respectively. (C) 2000 Elsevier Science Ltd. All rights r eserved.