Comparison of the Gout Reducing Properties of Decaffeinated and Non-Decaffeinated Coffee

Tey, Zi Tong (2020) Comparison of the Gout Reducing Properties of Decaffeinated and Non-Decaffeinated Coffee. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Xanthine oxidase (XO) enzyme is the cellular sources of superoxide radicals which catalyzes the oxidation reaction of hypoxanthine to xanthine and xanthine to uric acid. The accumulation of uric acid in the blood tends to cause gouty inflammation by its crystallization and deposition in the joint. The deposited crystal will cause intense pain, redness and swollen in the joint. In this study, gout reducing properties of the non-decaffeinated and decaffeinated coffee were investigated. The caffeine in the coffee is similar in structure with the allopurinol, a common drug used in XO inhibition. Therefore, it has the potential to compete or block the action of XO enzyme. In this study, allopurinol was employed as positive control. The results showed that the non-decaffeinated and decaffeinated coffee do not possess XO inhibitory activity at all concentrations tested. In the second part of the present study, the potential of coffee in neutralizing free radicals to reduce gouty inflammation was also investigated. One Way ANOVA analysis showed that non-decaffeinated coffee has higher DPPH radical scavenging activity compared to the decaffeinated coffee. The IC50 of the non-decaffeinated and decaffeinated coffee was 10.97 μg/ml and 18.59 μg/ml, respectively. Other than that, the non-decaffeinated coffee showed higher total phenolic content (39.76±0.28 mg GAE/g of coffee powder) than the decaffeinated coffee (37.04±0.22 mg GAE/g of coffee powder). However, the total flavonoid content of the non-decaffeinated coffee (32.06±0.44 mg QE/g of coffee powder) was lower than the decaffeinated coffee (36.93±0.23 mg QE/g of coffee powder). The results indicated that coffee do not possess xanthine oxidase inhibitory activity. Hence, the gout reducing properties of both the decaffeinated and non-decaffeinated coffee might be attributed to its antioxidant properties. Further study on the anti-inflammatory properties of coffee powder is recommended to be carried out in the future.