A Preliminary Study of the Xanthine Oxidase Inhibitory Potential of Various Types of Teas

Goh, Cheon Jou (2022) A Preliminary Study of the Xanthine Oxidase Inhibitory Potential of Various Types of Teas. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Gout is a metabolic condition that causes inflammation of the joints and the deposition of monosodium urate crystals (MSU) in tissues. The development of uric acid crystals requires an increase in serum uric acid (SUA) above a certain threshold, a condition known as hyperuricemia. In order to reduce uric acid formation, the teas such as green tea, rooibos tea and black tea are used in this research that may have the potential to act as anti-hyperuricemic agents and the ability to reduce uric acid levels for gout treatment. In purine metabolism, xanthine and hypoxanthine are oxidized into uric acid by xanthine oxidase. The hypouricemic effect of teas is thought to be due to the suppression of XOD activity, which lowers the production of uric acid. Teas are also high in antioxidants, which may help in reducing uric acid production. The objectives in this research are to compare the xanthine oxidase inhibitory activity, antioxidant activity, total phenolic content as well as to investigate the phytochemicals responsible for the XO inhibitory activity of green tea, blacktea and rooibos tea qualitatively. In this study, xanthine oxidase inhibitory (XO) assay, DPPH free radical scavenging and total phenolic content were investigated. The research findings in this study were that the teas investigated do not have XO inhibitory activity. By using One way ANOVA analysis, green tea gave the highest antioxidant activity followed by black tea and rooibos tea which provide IC50 DPPH inhibitory of 28.78μg/ml, 41.73μg/ml, and 54.28μg/ml, respectively. Next, black tea gave highest total phenolic content compared to rooibos tea and green tea which provide total phenolic content (mg GAE/g) of 5.031 ± 0.014 mg GAE/g, 4.182 ± 0.016 mg GAE/g, and 3.880 ± 0.01 mg GAE/g, respectively. Hence, green tea, black tea and rooibos tea that have the potential in gout treatment is due to the antioxidant properties. Future study of the anti-inflammatory properties of tea is suggested to be carried out