KHẢO SÁT HOẠT TÍNH ỨC CHẾ ENZYM XANTHIN OXIDASE VÀ TRUNG HOÀ GỐC TỰ DO DPPH CỦA MỘT SỐ SẢN PHẨM TRÀ TỪ CÂY CAMELLIA SINENSIS (L.) Kuntze

Abstract

Not only has the tea tree (Camellia sinensis) been used as a popular drink, but it is also a source of study in modern medicine since it has been proven to possess many health benefits. Aiming for providing supplementary information to the pharmacological profiles of tea trees, this study was carried out to measure the in vitro xanthine oxidase inhibitory effect and DPPH free radical scavenging capacity, to estimate the gout-relieving potential of this plant. Three brands of tea trees were investigated, including green tea, black tea, and oolong tea. These products were hot-macerated independently with ethanol 90% or distilled water, yielding six crude extracts. Through in vitro screening, all of the extracts showed a moderate capacity of DPPH free radical scavenging (IC₅₀ values range between 45 and 55 µg/mL, compared to acid ascorbic with IC₅₀ as 0.01 ± 0.00 µg/mL), the ethanol 90% extract of oolong tea exhibited quite strong inhibitory effect on xanthine oxidase (IC₅₀ as 24.63 ± 0.01 µg/mL, compared to allopurinol with IC₅₀ as 1.51 ± 0.00 µg/mL). The results suggested that oolong tea could potentially be a gout-relieving remedy.