Comparison of Antibacterial Activity in Ethanol Extract and Essential Oil of Citrus sinensis (L.) Peels Obtained by Sohxlet and Distillation Methods

Ethanol extract and essential oil of Citrus sinensis (L.) peels have been characterized and compared for its antibacterial activity. Ethanol extract of C. sinensis (L.) peels was obtained by Soxhlet extraction method in ethanol with purity of 96% and the essential oil was obtained by distillation method for 5 hours at 100°C. The antibacterial activities of the extracts were investigated against Staphylococcus aureus. The experimental results showed that the ethanol extract yielded 29.50% (w/w), with total flavonoid compounds of 4.74 mg/g and polyphenolic of 20.54 mg/g, while the water extract (essential oil) yielded 6.80% (w/w) with total polyphenolic compounds of 0.65 mg/g. The flavonoid compound was not observed in the essential oil obtained from distillation method. The bioactive compounds in the ethanol extract obtained by Soxhlet extraction are larger than those found in the essential oil obtained by distillation method. The ethanol extract showed stronger growth inhibitory effect of Staphylococcus aureus with zone inhibition diameter of 18 mm, whereas the essential oil and the commercial d-limonene extract had similar zone inhibition diameter of 15 mm.