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Distribution and Antioxidant Activities of Free, Conjugated, and Insoluble‐Bound Phenolics from Seven Species of the Genus Camellia
Author(s) -
Luo Fan,
Fei Xueqian
Publication year - 2019
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1002/aocs.12172
Subject(s) - gallic acid , catechin , camellia , camellia oleifera , abts , chemistry , antioxidant , camellia sinensis , food science , botany , polyphenol , biology , organic chemistry , biochemistry , dpph
Free phenolic (FP), conjugated phenolic (CP), and insoluble‐bound phenolic (IBP) acids were extracted from the seeds of seven species of oil‐tea camellia and their antioxidant activities were evaluated. The results indicated that Camellia vietnamensis has the highest total phenolic content (TPC) (31.84 ± 0.11 g of gallic acid equivalent [GAE] kg −1 ) and that Camellia polyodontia has the lowest TPC (12.34 ± 0.22 g GAE kg −1 ) in the kernel. The average TPC among the species is similar in both the kernels and in the shells, and the content order of the three forms of phenolic compounds is FP > IBP > CP. HPLC‐MS analysis showed the presence of 9–11 phenolic compounds in the FP, CP, or IBP extracts of the seven species of oil‐tea camellia seed. Among the phenolics identified, ferulic acid, catechin, and epicatechin were the major contributors of antioxidant activity. Hierarchical cluster analysis conducted based on the phenolic properties showed that C. vietnamensis and Camellia semiserrata belong to the group characterized by high antioxidant capacities (FRAP, ferric‐ion‐reducing antioxidant power; ABTS assay), and Camellia chekiangoleosa and Camellia oleifera are arranged in a group with moderate phenolic properties. The other species constitute the third cluster with low phenolic content and antioxidant activity. The study demonstrated that oil‐tea camellia seed contains significant amounts of phenolic acids. In addition, extracts from various parts of the seed could be interesting novel sources of natural antioxidants.