Conversion of Vernonia galamensis oil to pyridinyl-vernolamides and their antimicrobial activities

Abstract

Vernonia oil obtained by Soxhlet extraction from the seeds of Vernonia galamensis ssp. nairobensis was reacted with 2-aminopyridine, 2-(aminomethyl)pyridine and 2-(aminoethyl)pyridine using a 1:3 mole ratio of vernonia oil to amine at varied temperatures to give the corresponding vernolamides. The expected vernolamide from the reaction of 2-aminopyridine and the oil was not formed. N-(2-pyridinylmethyl)vernolamide and N-(2-pyridinylethyl)vernolamide exhibited antibacterial activity that was shown to be higher against gram-positive (Bacillus subtilis) than gram-negative (Escherichia coli) bacteria. The vernolamides did not show any antifungal activity.

KEY WORDS: Vernonia galamensis, 2-Aminopyridine, N-(2-pyridinylmethyl)vernolamide,     N-(2-pyridinylethyl)vernolamide, Antimicrobial activity

Bull. Chem. Soc. Ethiop. 2007, 21(1), 103-110.