Abstract:In order to study the metabolic components of Camellia oleifera kernels, and metabolites difference in seed kernel in Camellia drupifera and Camellia oleifera were explored at the same time, then antioxidant activity of kernels oils in Camellia drupifera and Camellia oleifera were detected. Broadly targeted metabolomics based on ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) was used to detect differential metabolites between Camellia drupifera and Camellia oleifera. The metabolites in the kernels of two Camellia species were compared via cluster analysis, correlation analysis and orthogonal partial least squares discriminant analysis (OPLS-DA). Finally, the seed kernel oil was extracted by Soxhlet extraction method, and the difference in antioxidant activity of the oil was compared. The results showed that 25 metabolites Camellia drupifera owned and 16 metabolites Camellia oleifera owned were filtered in the 536 metabolites belonging to 11 classes detected in the kernels of two Camellia species. 197 differential metabolites were filtered among the whole 536 metabolites, and made up 36.75%. Amond them, 103 metabolites were expressed higher in Camellia drupifera than Camellia oleifera, which made up 52.28% in total differentially expressed metabolites; 94 metabolites were expressed in lower levels than Camellia oleifera, which made up 47.72% of 197 differential metabolites; These 197 metabolites differentially expressed in two Camellia species mainly participated in 20 pathways, flavonoid biosynthesis, phenylpropanoid biosynthesis, tyrosine metabolism and anthocyanin biosynthesis were the pathways occupying top 4 differential metabolites, and there were 7 metabolites (3.55%), 5 metabolites (2.54%), 4 metabolites (2.03%) and 4 metabolites (2.03%), respectively. The variety and content of flavonoids and lipids in Camellia drupifera were more abundant than Camellia oleifera. The antioxidant activity tests showed that the DPPH free radical scavenging rate of Camellia drupifera seed oil was slightly higher than that of Camellia oleifera when the oil mass concentration was greater than 6.0 mg/mL, and when the oil mass concentration exceeded 0.4 mg/mL, the hydroxyl clearance rate of Camellia drupifera was slightly higher than that of Camellia oleifera. The seed kernels of Camellia drupifera were rich in flavonoids and phenolic acid compounds, and the types and content of lipids are more abundant than those in Camellia oleifera seed kernels. The difference expression metabolites of seed kernels may be the key factor affecting the composition and antioxidant activity of the two types of Camellia oil.