Studies on the Chemical Constituents of

Azadirachta indica A. Juss (Meliaceae) is indige­ nous to the Indo-Pakistan subcontinent and its various parts are reputed as therapeutic agents [2, 3]. Some of the constituents of neem have recently been shown to possess significant pesticidal activity [4]. More recent studies undertaken on the fresh, un­ dried, uncrushed, ripe and unripe, fruits and the un­ dried leaves of the plant by Siddiqui et al. have led to the isolation and structure elucidation of nine new triterpenoids viz, nimolicinol [5], nimocinol [6], azadirachtol [7], azadirachnol [8], nimbocinone [9], nimocinolide [10], isonimocinolide [10], nimocin [10] and nimolinone [1]; and two new nonterpenoidal components, nimbochalcin [11 ] and nimbocetin [1 1 ]. The present paper deals with the isolation of a new limonoid, nimbocinol (1 ), from the neem fruits along with known tetranortriterpenoids, azadirone [12], epoxyazadiradione [12], azadiradione (2) [12, 13], gedunin [12], 17-hydroxyazadiradione [13] and a sterol identified as cholesterol. The structure of nim­ bocinol has been determined as 1 through spectral and chemical studies. It has to be mentioned that cholesterol has not so far been reported from any part of the neem tree, although its occurrence has been noted in other plants such as Solanum xanthocarpum [14] and Solanum tuberosum [15].