Chemical constituents and antioxidant activity of essential oil and organic extract from the peel and kernel parts of <i>Citrus japonica</i> Thunb. (kumquat) from Iran

<p>The constituents of essential oils and organic extracts from peel and kernels of <i>Citrus japonica</i> were analysed by GC and GC/MS. The content of essential oil in peel and kernel was 1.1 and 0.8% based on dry weight. The essential oil of <i>C. japonica</i> peel and kernel was characterised by a higher amount of limonene (51.0 and 47.1%) and germacrene D (12.1 and 6.3%), and the hexane extracts of its peel and kernel were characterised by a higher amount of dodecanol-1(12.9 and 20.8%) and linolenic acid (13.1 and 16.3%), respectively. The antioxidant activities of oils were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The results indicate that both oils from different parts of <i>C. japonica</i> possess considerable antioxidant activity. The fruit peel and kernel essential oil could thus be useful in the industries, chiefly in the food and pharmaceutical industries.