Chemical constituents and antimicrobial activity of the leaf essential oil of Ixora coccinea L (Rubiaceae) collected from North Central Nigeria

Essential oils have found vast applications in many fields including aromatherapy, flavor and fragrance industries. Ixora coccinea Linn. is a reputable medicinal plant with long history of use in Nigeria. This study aimed to investigate the chemical constituents and antimicrobial activity of the leaf Essential Oil (EO) of Ixora coccinea grown in Nigeria. EO was obtained by hydrodistillation with yield of 0.16% (w/w). Chemical constituents of EO were determined using Gas Chromatography coupled to Mass Spectrometry (GC-MS). The GC-MS analysis identified 43 compounds, representing 94.67% of the oil constituents. The analysis revealed eight classes of compounds including hydrocarbons, alcohols, carboxylic acids, esters, aldehydes, ketones, sesquiterpenoids and triterpenoids. Hydrocarbons accounted for 33.77% with decane (11.12%) as the highest; alcohols comprised 28.86% of the oil with the highest being linalool (10.54%). Esters made up 14.15% of the oil. Carboxylic acid (10.91%) was dominated by malonic acid (10.26%); sesquiterpenoids made up 6.84% of the oil dominated by 3,7,11-trimethyl-1,6,10-dodecatrien-3-ol (3.07%). Aldehydes made up 3.36% of EO dominated by heptadecanal (2.30%). Ketones accounted for 1.38% of the oil. The inhibitory effect of EO was evaluated against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Mycobacterium tuberculosis (BCG) using broth microdilution method. The essential oil showed significant antimicrobial effects against the test organisms, with Minimum Inhibitory Concentration (MIC) ranging from 50 to 200 I¼g/mL. This result showed that EO could serve as adjunct therapy in the treatment of community acquired infections.