Investigation of Phytochemical and Antioxidant Capacity of Fennel (Foeniculum vulgare Mill.) Against Gout

Fennel, Foeniculum vulgare Mill. (Apiaceae) is an aromatic plant, with medicinal and culinary applications, widely naturalized worldwide, especially near the see coasts and riversides. Fennel has long been used in Iran as a traditional remedy against gout. The objective of our study was to uncover the scientific basis of this traditional gout therapy. Different plant parts were extracted by methanol and used in phytochemical assessment and examined for possible inhibitory effects on xanthine oxidase -the main enzyme responsible for uric acid accumulation in blood. FRAP and β-carotene bleaching assays, total anthocyanin, carotenoids, soluble sugars, phenolics and flavonoids content were measured spectrophotometrically, while caffeic acid, chlorogenic acid and quercitin contents were measured by HPLC. The experiments were performed using a 3-stage nested statistical design with three biological replications. Results showed that the flower extract exhibited the most xanthine oxidase inhibitory effect (80% of Allopurinol), the highest amounts of total phenol, flavonoid and cafeic acid (53.55, 7.71 and 0.049 mg gdw-1,respectively), as well as significant antioxidant activity in scavenging free radicals. These results suggest that flower extract of fennel is a natural source of valuable compounds against xanthine oxidase activity, with potential therapeutic applications in human gout treatment.