Comparative study of ovatifolin antioxidant and growth inhibition activities

A comparative study on the effect of arturin (1), ovatifolin (3), deacetylo vatifolin (5), and their 1-acetoxyarturin (2), 8-acetoxyovatifolin (4), 1,1 0-epoxyovatifolin (6), and 11,13-dihydroovatifolin (7)derivatives, isolated from Podanthus ovatifolius and Podanthus mitiqui, on the seedling growth, germination, and respiration of several monocot and dicot weedy target spec ies was carried out. In addition to the inhibitory activity on the bleachin g of crocin induced by alkoxyl radicals, these compounds also displayed sca venging properties toward DPPH in TLC autographic and spectrophotometric as says. The results indicate that ovatifolin (3), deacetylovatifolin (5), epo xyovatifolin (6), dihydroovatifolin (7), and the CH2Cl2 extract interfere w ith pre-emergence of seedlings at the level of respiration. These compounds appear to have selective effects on the radicle and shoot growth of Physal is ixocarpa and Trifolium pratense. Their allelopathic effects are comparab le to those of parthenolide, a know natural growth inhibitor.