New Tetranortriterpenoids from Swietenia humilis (original) (raw)

1993, Journal of Natural Products

FOU~ new tetranortriterpenoids, humilinolides A Ill, B 127, C 131, and D 147, were isolated from the seeds of Swietenia burnilis (Meliaceae). The structures of compounds 1 4 were established by spectroscopic methods. The structure of humilinolide A 111 was confirmed unequivocally by single crystal X-ray diffraction studies. The effect of the MeOH extract of the seeds and the isolated terpenoids 1 4 on the radicle growth of Amaranth hypochondriacus and Echinochloa m-galli was evaluated. The extract and compounds 1 and 3 caused significant inhibition on radicle elongation in both target species. In addition, the MeOH extract of seeds of S. burnilis showed moderate inhibition to the growth and feeding of the third instar larvae of Tenehio molitw. Swietenia burnilis Zuccarini (Meliaceae), locally known as "topilote," "cobano," "caobilla," and "sopilocuahuilt," is a tree up to 20 m high. It grows commonly in the tropical areas of Mexico, in Guerrero, Michoacan, Colima, Sinaloa, and Chiapas, where the trees are most often seen as scattered and isolated individuals (1,2). The seeds of this plant are highly valued for their medicinal properties in some regions of Mexico (2-5). Decoctions or infusions of the ground seeds are used as anthelmintic agents and for the cure of amebiasis (4). They are also considered effective for treatment of chest pains, coughs, and cancer (5). S. burnilis has recently been listed as an endangered species in need of conservation (1). Previous phytochemical analysis conducted with the seeds led to the isolation and characterization of three tetranortriterpenoids of the mexicanolide group, namely, humilin B, 2-methyl-2-hydroxy-3-isobutyryloxymeliac-8(3O)-enate, and 2-methyl-3tygloyloxymeliac-8(3O)-enate (5). Continuing our search for biologically active substances from Mexican medicinal plants (7,8), we have investigated the seeds ofS. burnilis. In this paper we describe the isolation and structure elucidation of four new tetranortriterpenoids, humilinolides A 111, B 121, C {3], and D {4], as well as their effect on the radicle growth of Amaranthus bypocbondriaws L. and Ecbinocbloa crus-galli (L.) Beauv. The feeding deterrence and growth inhibition of the MeOH extract of dry seeds of S. burnilis on third instar larvae of Tenekio mlitor were also investigated. 'Chemical Studies on Mexican Plants used in Traditional Medicine XXVIII. For part XXVII see M.R.