Antioxidant and Anti-obesity Activities of Roasted Camellia japonica Leaves Extract

Abstract

When natural substances containing polyphenols are heated, the structure of polyphenols have been changed to result in the change of biological activities. In addition, this process imparts new flavors and tastes by preserving moisture and reducing unnecessary flavors. Camellia japonica has been reported to possess physiological activities in various parts of the plant, including leaves (CJL), flower buds, and stems. However, there is a shortage of reports on the physiological activities of extracts subjected to heat treatment. This study evaluated the antioxidant activities, the total phenolics content, total flavonoid content, and anti-obesity activity (αglucosidase inhibition activity and lipase inhibition activity) of heat-treated C. japonica leaves (CJLH) extract. HPLC and LC-MS/MS techniques were used to verify any alterations in the active ingredient content. Our findings demonstrated that CJL displayed substantial antioxidant and anti-obesity activity. HPLC analysis revealed that catechin was the highest among the polyphenol components. L-Ascorbic acid was detected at high levels in CJL, CJLH1, and CJLH2, but was presumed to be lost due to thermal decomposition in CJLH3 and CJLH4 (The number means different process). In LC-MS/MS analysis, catechin had the highest content and CJLH3 had the highest polyphenol content among the extracts. Based on the data, CJLH can be useful as natural cosmetics, food materials for flavor enhancement and anti-obesity applications.