Chemical Composition and In vivo Anti-inflammatory Activity of Essential Oils from Citrus sinensis (L.) osbeck Growing in South Africa

The purpose of this study is to determine the chemical profile of the essential oils extracted from South African grown Citrus sinensis (L.) osbeck leaf and peels (fresh and dried) using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) and evaluate the essential oils anti-inflammatory potential. The analysis gave forty and fifty-four compounds accounting for 91.5 % and 99.6 % respectively identified in fresh and dried leaf essential oils. The major compounds in fresh leaf essential oil were sabinene (20.4 %) and terpinen-4-ol (13.2 %) while β-elemene (16.3 %) and sabinene (10.7 %) were identified in dried leaf essential oil. In fresh and dried peel oils, twenty-four and twenty-five compounds accounting for 99.3 % and 99.4 % respectively were identified whereby limonene (80.5-73.6 %) was the most prevalent compound. Citrus sinensis dried leaf and peel bioactive essential oils compounds significantly (p< 0.01) suppressed oedema in rats hind paw mostly at 200 mg/kg dose level indicating good anti-inflammatory activity. The abundance of limonene in Peels essential oil and β-elemene and sabinene in leaf essential oil played a significant role in anti- inflammatory properties of Citrus sinensis. To the best of our knowledge, this is the first comprehensive chemical profile report on South African grown C. sinensis despite being a major citrus producing country.