Efficacy evaluation of a Chinese bitter tea (Ilex latifolia Thunb.) via analyses of its main components

Abstract

In order to evaluate the health effects of Ilex latifolia Thunb., a Chinese bitter tea widely consumed as a health beverage, flavonoids, saponins, polysaccharides and alkaloids were extracted from its leaves and their in vitro antioxidant activity, anticomplement system activity, antiproliferative effects against human cervical carcinoma Hela cells, and anti-inflammatory effects against mouse macrophage RAW 264.7 cells were analyzed. Results showed that the polysaccharides exhibited a considerable inhibition of the complement system, the hemolysis inhibition rate reached 98% at a concentration of 0.8 mg mL⁻¹, which was clearly higher than that of the positive control (heparin sodium). The total flavonoids displayed significant DPPH scavenging activity and an inhibition effect on the generation of NO in LPS-induced RAW 264.7 macrophages. In addition, the total saponins showed a better antiproliferative effect against Hela cells, and the total alkaloids exhibited a high reducing power. It is obvious that I. latifolia has a variety of nutritional and health functions which are attributed to its different components. The analysis method presented in this research can suggest lessons for analysis of other plant foods.