POTENTIAL ALLELOPATHIC LUPANE TRITERPENES FROM BIOACTIVE FRACTIONS OFMELILOTUS-MESSANENSIS

The aerial parts of Melilotus messanenis (sweet clover) afforded, from the medium polar bioactive fractions, in addition to the known lupane triterpenes lupeol, betulin, betulin aldehyde and betulinic acid, the new norlupane messagenin (30-norlupane-3 beta,28-diol-20-one) which h ave been tested as allelochemicals. Structures and their stereochemist ries were elucidated by spectral methods and chemical transformations. Messagenin has been synthesized from betulinic acid. The effect of a series of aqueous solutions at 10(-4)-10(-9) M of eight natural and sy nthetic lupane derivatives were tested for their effects on the germin ation and growth of the dicotyledon species Lactuca sativa and Lepidiu m sativum and the monocotyledon species Hordeum vulgare and Triticum a estivum. All eight lupane triterpenes possess potential allelopathic a ctivity in particular over dicotyledon species and they are likely to be significantly involved in the allelopathic action of Melilotus mess anensis.