Essential oil constituents and in vitro antimicrobial activity of the root of Mondia whitei (Hook. F.) Skeels (Periplocaceae)

The composition of the essential oil of the root of Mondia whitei was analysed by gas chromatography-mass spectrometry (GC/MS). The agar-well diffusion technique was used for the antimicrobial assay of the oil against nine clinical pathogenic organisms viz. Bacillus cereus, Escherichia coli, Candida albicans, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Salmonella typhi, Staphylococccus aureus and Streptococcus pyogenes. Twenty-eight compounds representing 99.92% of the essential oil were characterized. The major constituents of the oil were (E)-2-hexen-1-ol (25.96%), heptacosane (20.94%), phytol (15.60%), 1-hexanol (8.94%), (E)-2-hexenal (4.29%) and 2-hydroxy-p-anisaldehyde (4.21%). At 106 cfu/ml inoculums concentration, the oil was most active against E. coli (50.0 mm) and S. aureus (48.3 mm) and least active on C. albicans (15.0 mm). Generally, the oil exhibited significant (P ≤ 0.05) antimicrobial activity against the test organisms. The observed antimicrobial activity justify the ethnomedicinal uses of M. whitei in Nigeria. Key words: Essential oil, Mondia whitei, root, (E)-2-hexen-1-ol, pathogenic organisms, antimicrobial assay.