Activity and dermal safety of Citrus limon (L.) Burm. f oil from Soroti, Uganda against selected Gram positive and Gram-negative bacteria.

Abstract

Background: Essential oils are widely used for culinary and nonculinary purposes like nutraceuticals, traditional medicine, aromatherapy and cosmetics. Genus citrus of the Rutaceae family has several plants including Citrus limon (C. limon) that are rich in essential oils known to have strong antibacterial activity. Citrus limon extracts are locally used in Uganda as astringent, to treat skin and mucocutaneous conditions. However, composition of essential oils varies with geographical origin of the plant and this may compromise their efficacy and safety. The main aim of this study was to evaluate activity of C. limon on both gram-negative and gram-positive bacteria and assess its dermal safety. Methodology: Citrus limon peel oil was extracted from fresh peels by hydro distillation using Clevenger’s apparatus for 6 hours and phytochemicals were identified by gas chromatography. Antibacterial activity was evaluated using Agar well diffusion and broth dilution methods, while dermal safety was evaluated using Draize’s method. Results: Yield of peel oil was 0.20%, D-limonene, terpineol and sabinene were the major chemical components identified. Only the gram-positive bacteria were susceptible to C. limon peel oil, the largest zones of inhibition were observed with Staphylococcus aureus and its minimum inhibitory concentration (MIC) was 105mg/ml. C. limon peel oil caused mild dermal irritation with no oedema in albino rabbits on a single exposure. Conclusion: Citrus limon oil has antibacterial activity on Staphylococcus aureus and Streptococcus pyogenes. When applied on albino rabbit skin, C. limon oilcauses hyper sensitivity reaction at a dose of 210 mg/ml and above.