Natural variation on free, esterified, glycosylated and insoluble-bound phenolics of Rubus chingii Hu: Correlation between phenolic constituents and antioxidant activities.

[Display omitted] • Variations of phenolic components in Rubus chingii Hu during ripening were studied. • Quantity of four fractions of phenolics during ripening were characterized. • Changes of antioxidant properties in Rubus chingii Hu during ripening were studied. • The highest contribution fractions for the antioxidant activities were determined. This study sought to determine how the variation of soluble free phenolics (SFPs), soluble-bound (including esterified-bound phenolics (EBPs), glycosylated-bound phenolics (GBPs)) and insoluble-bound phenolics (ISBPs) affected the antioxidant properties (radical scavenging activities and oxidative damage caused by H 2 O 2 in RAW264.7 cell) of Rubus chingii Hu during different maturity stages. Our result demonstrated that the young fruit stage could be considered as a proper harvesting period for Rubus chingii Hu to obtain high antioxidant activities. Distinct tendencies about abundance were found in four phenolic forms and followed the order: SFPs ≈ EBPs > GBPs ≈ IBPs, and antioxidant activities correlation: EBPs > GBPs > SFPs. Furthermore, total phenolic content, total flavonoid content and phenolics such as kaempferol-3-O-rutinoside, tiliroside and ellagic acid have a substantial correlation with antioxidant capacity. This study may supply a theoretical foundation for the utilization and exploitation of Rubus chingii Hu in different maturity periods. [ABSTRACT FROM AUTHOR]