Antioxidant activities of Uyghur medicinal tea in human HL-60 cell line and rat hepatic microsomes

Abstract

Uyghur medicinal tea (UMT) is preferably used as a common nutritional additive by Uyghur population, especially by the aged people including centenarians from southern part of Xinjiang, along the Silk Road of China. The study showed an evidence for the antioxidant properties of UMT extract by using two different oxidative systems in vitro: (1) the myeloperoxidase/H2O2/HOCl enzymatic system in human HL-60 cell line and (2) the cytochrome P450/NADPH reductase system in rat liver microsomes. The EGB 761 Ginkgo biloba extract was used as the reference. Reactive oxygen species (ROS) production was measured by fluorescence of 2’,7’-dichlorofluorescein (DCF) originated from 2’,7’-dichlorofluorescein diacetate (DCFHDA) probe oxidation. UMT extract inhibited ROS formation by 81, 86 and 73% in the HL 60 cell line system (at the concentrations of 0.25, 0.50 and 0.75 mg/ml) and at similar rates in the microsomal system. In the same conditions, G. biloba extract inhibited ROS activity by 39, 78 and 81% in HL 60 cells, and by 78, 87 and 89% in the microsomal system. The present study shows that UMT possesses relatively high antioxidant activity, comparable to the free radical scavenger properties of EGB 761 extract. This effect could explain its benefic preventive action against age-related pathologies. Habitual consumption of UMT may provide beneficial effects in prevention of atherosclerosis and oxidative stress in aging process. Key words: Uyghur medicinal tea, antioxidant activity, HL 60 cells, hepatic microsomes.