Antifungal Activity of Withametelin, a Withanolide Isolated from Datura metel

Withametelin, a steroidal compound isolated from leaves of Datura metel L.(Solanaceae), showed antifungal activity against some plant pathogenic as well as saprophytic fungi tested in vitro. Except Curvularia maculans and Colletotrichum sp., spore germination of all the other 23 fungi was inhibited significantly at 125 to 1000 ppm. Out of the 25 fungi tested, Curvularia sp., Cercospora abelmoschi, Heterosporium sp., Erysiphe cichoracearum and Ustilago cynodontis were most sensitive as there was complete inhibition of germination at 1000 ppm. Similarly, spores of Alternaria brassicae, Curvularia lunata and Helminthosporium pennisetti showed less than 3% germination at the same concentration. Rest of the fungi showed more than 15% spore germination at the same concentration.