Evaluation of the antimicrobial and phytochemical properties of oil from castor seeds (Ricinus communis Linn)

Abstract

The antimicrobial activity of the essential oil of castor (Ricinus communis) seeds extracted using soxhlet extractor in 98% nhexane was assessed using in-vitro assay. Twenty microorganisms made up of fourteen bacteria and six fungi were used in the bioassay. Comparatively, bacteria were found to be more susceptible than fungi. The minimum inhibitory concentration (MIC) of the extract was found to range between 6.25 mg/ml and 12.50 mg/ml for bacteria while that of fungi ranged from 12.50 mg/ml to 25.00 mg/ml. Comparison of the antimicrobial efficacy of the extract and commercial antibiotics showed that the latter were more potent against the test organisms with the exceptions of erythromycin, ampiclox and rifampin group for Gram positive organisms and, septrin and ceporex group for Gram negative organisms respectively. The quantitative phytochemical screening showed that tannin, phenol, alkaloid, phytate, oxalate, saponin, cyanogenic glycoside and flavonoid were present in a decreasing order. The spectrophotometric data of the extract using ultraviolet radiation, infrared and HNMR as well as carbon 13 NMR showed the presence of various compounds such as cineole, 2-octanol, terpenene-4-ol, limonene, sabinene, pinene, terpinene, and methyl groups in the oil.