CHEMICAL COMPOSITION AND ANTI-MICROBIAL ACTIVITY OF ESSENTIAL OIL FROM LEAVES OF RAPANEA WIGHTIANA

Abstract

The essential oil from leaves of Rapanea wightiana was obtained by hydrodistillation and the chemical composition was determined by GC and GC-MS. The main components identified in myrcene followed by spathulenol limonene Germacrene D and farnesol A major portion of oxygenated fraction of the oil was comprised by alcohols. Methyl eugenol, dihydrocarveol, borneol, isothujanol, isopulegol, nerolidol, spathulenol, β-bisabolol and farnesol. Subsequently the oil was evaluated for antimicrobial activity against two gram-positive and two gram-negative bacteria and four pathogenic fungi using agar disc diffusion technique. Further the minimum inhibitory concentration (MIC) was also determined. Among all the bacteria tested, B. subtilis was most susceptible at 100μg/ml with zone of inhibition of 26.3 mm. While, among all the fungal species tested, A. niger inhibited more effectively at 100μg/ml with a zone of inhibition of 23.2 mm. The results obtained suggests that the essential oil of this plant possess excellent antimicrobial properties where there is a need to explore this plant as an alternative bio-friendly natural antimicrobial agent.