Chemical Composition and Antibacterial Activity of Fruit Essential Oil of Xylopia aethiopica D. Grown in Nigeria

Abstract

Qualitative and quantitative analyses of the chemical constituents of fruit essential oil of Xylopia aethiopica and its antibacterial activity were investigated. Pulverized fruit of X. aethiopica was hydrodistilled in a Clevenger type apparatus. The resulting oil was characterized by Gas chromatography-Mass spectrometry (GC-MS) and its antibacterial activity was evaluated using agar diffusion method. Hydro-distilled X. aethiopica fruits yielded 1.3 % v/w of essential oil. Investigation by GC-MS revealed that bulk of the oil was constituted by hydrocarbon monoterpenes (44.0 %). The major constituents of the oil were; Eugenol (12.2 %), acetyleugenol (7.0 %), 1,8-cineole (6.8 %), sabinene (6.7 %), cis-ocimene (6.2 %), β-caryophyllene (5.6 %), γ- terpinene (5.3 %), α-pinene (4.3 %), β-linalool (4.3 %), α-terpineol (4.1 %), pinocarveol (3.7 %), terpinene-4-acetate (3.6 %), α-thugene (3.6 %), β-phellandrene (3.5 %) and benzylbenzoate (3.3 %). The oil showed various degree of inhibitory effect against three gram positive bacteria; Streptococcus pyogenes, Staphylococcus aureus, Bacillus subtilis and four gram negative bacteria; Enterobacter aerogenes, Klebsiella pneumoniae, Escherichia coli, Serratia marcescens, while no activity was recorded against Proteus mirabilis. The calculated activity index compared favourably with the standard gentamycin antibiotic used as control. Data from this study showed that aromatic compounds predominates the fruit essential oil of X. aethiopica growing in North Central Nigeria and the oil is active against a broad spectrum of clinical bacterial isolates.