Bioactive comparison of main components from unripe fruits of Rubus chingii Hu and identification of the effective component.

Dried and unripe fruit of Rubus chingii Hu, known as "Fu-pen-zi" in Chinese, has been used as a food and tonic in China for a long time. In order to analyze its effective ingredients, polysaccharides, flavonoids, saponins and alkaloids were extracted from the unripe fruits and their contents were determined. The in vitro antioxidant, anticomplementary and anticancer activities against human lung adenocarcinoma A549 cells of the four major constituents were investigated. Results showed that total flavonoids exhibited an obvious antioxidant activity, which was very close to ascorbic acid. The anticomplementary and anticancer activities of flavonoids were also the best among the four chemical compositions. Therefore, extraction process optimization of flavonoids was conducted using response surface methodology. The optimal conditions were as follows: extraction temperature 72.8 °C, ethanol concentration 30.67%, extraction time 2.66 h, and a liquid/solid ratio of 19.54 : 1. In addition, total flavonoids were subsequently separated by column chromatography and the major flavonoid was identified as tiliroside. Further experimental data revealed that tiliroside treatment could suppress the proliferation and induced the apoptosis of A549 cells.