Homoisoflavonoids and xanthones from the tubers of wild and in vitro regenerated Ledebouria graminifolia and cytotoxic activities of some of the homoisoflavonoids

Eleven homoisoflavonoids and two xanthones were isolated and characterized from the bulbs of Ledebouria graminifolia. Five of the homoisoflavonoids are new compounds and were identified as: 5-hydroxy-7-methoxy-3-(4'-hydroxybenzyl)-4-chromanone, 5-hydroxy-6,7-dimethoxy-3-(4'-hydroxybenzyl)-4-chromanone, 5,7,8-trimethoxy-3-(4'-hydroxybenzyl)-4-chromanone, 5-hydroxy3',4',7-trimethoxyspiro{2H-1-benzopyran-7'-bicyclo[4.2.0]octa[1,3,5]-trien}-4-one, 5,7-dihydroxy-3',4'-dimethoxyspiro{2H-1-benzopyran-7'-bicyclo [4.2.0]octa[1,3,5]-trien}-4-one. Structures were elucidated by extensive 1D, and 2D NMR spectroscopy and HRMS. A method for tissue culture was developed and the bulbs of mature plants were found to contain all the compounds isolated from the wild specimens of L. graminifolia. (C) 2003 Elsevier Science Ltd. All rights reserved.