Antioxidant and radical-scavenging activities of petal extracts of Camellia japonica ecotypes

Abstract

Camellia japonica is the most well-known species of the genus Camellia, which is native to Korea, Japan, and China. In this study, the antioxidant and free radical-scavenging activities of petal extracts of Camellia ecotypes with different colors were evaluated. For total phenolic compounds, five ecotypes were grouped into low [(4.8 mg·g−1 of dry weight (DW) GAE (gallic acid equivalent)], medium (6.0–6.2 mg·g−1) and high (19.6 mg·g−1) groups for white, red, and pink colors, respectively. The DPPH radical scavenging activity of the petal extracts, presented as a half maximal inhibitory concentration (IC50), was the greatest (3.8 μg·mL−1) in the pink ecotype and least (43.1 μg·mL−1) in the white ecotype as compared to ascorbic acid (13.6 μg·mL−1). The results demonstrated that the efficient DPPH radical scavenging activity of the pink ecotype was partly due to higher contents of phenolic compounds. Activities of two antioxidant enzymes, catalase and peroxidase, varied among the ecotypes, indicating the presence of ecotype-specific detoxifying processes. Camellia petals had higher amounts of antioxidants as well as excellent reactive oxygen species (ROS) scavenging activities that were dependent on the petal color.