In vitro xanthine oxidase inhibitory activity of leaves, fruits and peel extracts of Citrus aurantium, Citrus limetta and Citrus limon

Abstract

Aim of the study: To evaluate the in vitro xanthine oxidase inhibitory activity of the extract of leaves, fruits and peel of Citrus aurantium, Citrus limetta and Citrus limon. Materials and Methods: Xanthine oxidase inhibitory activity was assayed spectrophotometrically under aerobic conditions and the degree of enzyme inhibition was determined by measuring the increase in absorbance at 295nm associated with uric acid formation. Results: Among the extracts tested, the C. limetta peel extract exhibited highest potency of xanthine oxidase inhibition (IC 50 40.16±0.88µg/ml). This was followed by C. aurantium peel (IC 50 51.50±2.05µg/ml), C. limon peel (IC 50 64.90±1.24µg/ml), C. aurantium leaf (IC 50 73.50±1.26µg/ml), C. limetta leaf (IC 50 74.83±2.42µg/ml), C. limon leaf (IC 50 76.83±2.02µg/ml), C. limetta fruit (IC 50 95.16±0.60µg/ml) extracts compared with the IC 50 value of standard allopurinol was 6.6µg/ml. Conclusion: Recent findings show that the occurrence of gout is increasing worldwide, possibly due to the changes in dietary habits like intake of food rich in nucleic acids, such as meat, sea foods, etc. Xanthine oxidase inhibitors such as allopurinol is the drug of choice, however it has been observed more side effects. An alternative to allopurinol is the use of medicinal plants; we thus began our program to look for xanthine oxidase inhibitors of phytochemical origin. In conclusion, the study suggests that the leaves and peel extracts of Citrus aurantium, Citrus limetta and Citrus limon possess xanthine oxidase inhibitory activity that might be helpful in preventing or slowing the progress of gout and related disorders.