ISOLATION AND STRUCTURE ELUCIDATION OF NEW NITRILE AND MUSTARD OIL GLYCOSIDES FROM MORINGA-OLEIFERA AND THEIR EFFECT ON BLOOD-PRESSURE

Bioassay-guided analysis of an EtOH extract of Moringa oleifera leaves showing hypotensive activity led to the isolation of two nitrile glyc osides, niazirin [1] and niazirinin [2], and three mustard oil glycosi des, -acetyl-alpha-L-rhamnosyloxy)benzyl]isothiocyanate [4], niazimini n A, and niaziminin B. Glycoside 2 is a new compound. Niaziminins A an d B have previously been obtained from the leaf extract as a mixture, while compound 4 is new from this source. Structural determination was accomplished by means of spectroscopic methods including appropriate 2D nmr experiments and chemical reactions. This is the first report of the isolation of nitriles, an isothiocyanate, and thiocarbamates from the same plant species. Isothiocyanate 4 and the thiocarbamate glycos ides niaziminin A and B showed hypotensive activity while nitrile glyc osides 1 and 2 were found to be inactive in this regard.