An alkaloid constituent 1-[5-(1,3-benzodioxol-5-yl)-1-oxo-2,4-pentadienyl]piperidine, trivial name piperine was isolated from Ludwigia hyssopifolia Linn. (Family-Onagraceae). The ethylacetate extract of the plant and the isolated compound piperine were studied for antitumor and in vitro