Antioxidant Activity and Total Phenolics of Camellia oleifera Abel. Fruit Hull from Different Regions of China

摘要

The tea oil camellia, Camellia oleifera Abel., is used extensively in China as cooking oil. The antioxidant activity and antiradical activity of five C. oleifera fruit hull extracts from the major producing regions of China were examined. The content of total phenolics and extractable condensed tannins (ETC) in the extracts was calculated. Remarkable high phenolic content (gallic acid equivalent, GAE > 144 mg/g), extractable condensed tannin content (ETC > 96 mg/g), strong reducing ability (ascorbic acid equivalent, AAE > 5.5 mg/g) and antiradical activity (IC50<2.1 mg/mL) were found in samples from Guangxi, Jiangxi, Hunan and Zhejiang. The best results were obtained for the samples from Guangxi (phenolic content as GAE=234.90 mg/g, extractable condensed tannin content as ETC=166.98 mg/g, reducing power as AAE=12.91 mg/g and DPPH radical scavenging ability as IC50=899.25 μg/mL). A significant correlation was observed between reducing ability and the content of phenolic compounds of respective extracts. The results indicate promising C. oleifera fruit hull for the utilization as significant source of natural antioxidant.