The Antibiotic Principle of Seeds of Moringa oleifera and Moringa stenopetala

4(α-L-Rhamnosyloxy)benzyl isothiocyanate was identified as an active antimicrobial agent form seeds of Moringa oleifera and M. stenopetala. Roots of M. oleifera only contain this compound and benzyl isothiocyanate, but not pterygospermin as previously suggested. Defatted and shell free seeds of both species contain about 8-10% of 4(α-L-rhamnosyloxy)benzyl isothiocyanate, but this amount is produced from M. oleifera only when asorbic acid is added during water extraction. The compound acts on several bacteria and fungi. The minimal bactericidal concentration in vitro is 40 µmol/l for Mycobacterium phlei and 56 µmol/l for Bacillus subtilis.