Allelopathic Activity of a Novel Compound, Two Known Sesquiterpenes, and a C13 Nor-Isopenoid from the Leave of Croton oblongifolius Roxb. for Weed Control

Investigation of allelopathic substances from herbal plants may lead to the development allelochemical-based natural herbicides. Croton oblongifolius (Roxb.) is a well-known plant with long history being used for traditional medicines and source diverse range bioactive compounds. This has been reported have potential; however, its allelopathic-related not yet described. Therefore, we conducted this investigation explore leaves C. oblongifolius. Aqueous methanol extracts exhibited significant growth inhibitory potential against four test (monocot barnyard grass timothy, dicot cress lettuce). The leaf were purified in various chromatographic steps yielded active compounds identified as (3R,6R,7E)-3-hydroxy-4-7-megastigmadien-9-one (I), 2-hydroxy alpinolide (a novel compound) (II), (III), epialpinolide (IV) via an analysis spectral data. These significantly restricted seedling cress. concentration necessary 50% reduction seedlings varied 0.15 0.24 mM (3R,6R,7E)-3-hydroxy-4-7-megastigmadien-9-one, 0.04 0.11 alpinolide, 0.07 0.12 0.09 0.16 epialpinolide. characterized be weed-suppressive resources weed control.