Comparison of Bioactive Compounds and Antioxidant Activities in Differentially Pigmented Cerasus humilis Fruits.

Chinese dwarf cherry () is a wild fruit tree and medicinal plant endemic to China. Its fruits are rich in various bioactive compounds, such as flavonoids and carotenoids, which contribute greatly to their high antioxidant capacity. In this study, the contents of bioactive substances (chlorophyll, carotenoids, ascorbic acid, anthocyanin, total flavonoids, and total phenols), antioxidant capacities, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonicacid) (ABTS) scavenging ability, and ferric-reducing antioxidant power (FRAP)) in differentially pigmented fruits of four varieties were determined and compared. The results revealed that anthocyanin, total flavonoids and total phenols were the three main components responsible for the antioxidant activity of . fruits. 'Jinou No.1' fruits with dark red peel and red flesh had the highest contents of anthocyanin, total flavonoids, and total phenols, as well as the highest antioxidant capacities; 'Nongda No.5' fruits with yellow-green peel and yellow flesh had the highest contents of carotenoids and chlorophyll, while 'Nongda No.6' fruit had the highest ascorbic acid content. To further reveal the molecular mechanism underlying differences in the accumulation of carotenoids and flavonoids among differentially pigmented fruits, the expression patterns of structural genes involved in the biosynthesis of the two compounds were investigated. Correlation analysis results revealed that the content of carotenoids in fruits was very significantly positively correlated with the expression of the , , , , , , , and genes ( < 0.01) and significantly negatively correlated with the expression of ( < 0.05). The anthocyanin content was very significantly positively correlated with , , and expression ( < 0.01). The total flavonoid content was very significantly positively correlated with the expression of , , and ( < 0.01) and significantly positively correlated with expression ( < 0.05). This study can provide a basis for understanding the differences in the accumulation of bioactive substances, and is helpful for clarifying the mechanisms underlying the accumulation of various carotenoids and flavonoids among differentially pigmented fruits.