Identification of polyphenolic composition in the fruits of Rubus chingii Hu and its antioxidant and antiproliferative activity on human bladder cancer T24 cells

Rubus chingii Hu, namely “Fu-pen-zi” in Chinese, is commonly used as a functional food in China. A rapid and sensitive High performance liquid chromatography (HPLC) coupled with linear ion trap-OrbiTrap hybrid mass spectrometer (LTQ OrbiTrap MS) was employed to identify the polyphenolic compounds in R. chingii fruits. A total of 18 compounds were identified in R. chingii polyphenols (RCPs), including five phenolic acids, four ellagitannins, and nine flavonoids. Additionally, the total phenolics, total flavonoids and total tannins content as well as antioxidant and antiproliferative activity were evaluated for the first time. The contents of total phenolics, total flavonoids, and total tannins were 356.42 mg GAE g−1 of extract, 201.94 mg RUE g−1 of extract and 155.12 mg GAE g−1 of extract, respectively. Antioxidant assays showed RCPs had favorable DPPH and OH− radical scavenging capacity and strong ferric ion reducing power. Moreover, the results also indicated the RCPs could inhibit cell proliferation and induce the cell apoptosis in T24 bladder cancer cells. Altogether, the results suggest R. chingii possesses potent antioxidant properties and could inhibit the growth of T24 cells by inducing the cell apoptosis in a dose-dependent manner.