Isothiocyanates in myrosinase treated herb extract of Cleome chrysantha decne. and their antimicrobial activities.

Abstract

GC/MS analysis of the volatiles produced by the action of endogenous myrosinase in Cleome chrysantha Decne. herb, showed three major components, 1-isocyano-4-methyl benzene, gamma-muurolene and (cis) nerolidole (21.72%, 12.15% and 10.39%, respectively). 1-isocyano-4-methyl benzene is not produced from myrosinase treated seeds of Cleome chrysantha Decne., while muurolene and nerolidole were found at higher concentrations 16.1% and 13.67%, respectively. Some other isothiocyanates identified in the seeds and leaves, but in low percentages, were 2-methylbutyl isothiocyanate, 4-methylthiobutyl isothiocyanate and isothiocyanatomethyl benzene. Enzymatic hydrolysis of the ethanol extract of Cleome chrysantha Decne., produced two non-volatile isothiocyanates, 4, 6-dimethyltetrahydro-1,3-oxazine-2-thione and N-(-4-methyl-sulphinyl-3-butenyl) isothiocyanate which was established by aniline and methanolic ammonia to give the stable form of phenyl thiourea. They were identified by their spectroscopic data. These two isothiocyanates and the volatiles of the herb showed good antimicrobial activity against E. coli, Pseudomonas putida and Rhizobium meloloti (gram-negative bacteria) and moderate activity against Bacillus subtilis and Streptococcus lactis (gram-positive bacteria).