Antifeedant Activity of Withanolides fromSalpichroaoriganifoliaonMuscadomestica

The antifeedant effect of several salpichrolides on larvae of Musca domestica was investigated. Three naturally occurring compounds, salpichrolide A. (1), salpichrolide C (2), and salpichrolide G (3), previously isolated from Salpichroa origanifolia, and two known (4, 6) and three new (5, 7, 8) synthetic analogues were tested. The maximal effect on development was observed for salpichrolide A (1), while salpichrolide G (3) was the most toxic. The content of the salpichrolides in S. origanifolia was monitored by HPLC during plant development, reaching a maximum during summer.