A review of phytotherapy of gout: perspective of new pharmacological treatments

The purpose of this review article is to outline plants currently used and those with high promise for the development of anti-gout products. All relevant literature databases were searched up to 25 March 2013. The search terms were 'gout', 'gouty arthritis', 'hyperuricemia', 'uric acid', 'xanthine oxidase (XO) inhibitor', 'uricosuric', 'urate transporter 1(URAT1)' and 'glucose transporter 9 (GLUT9)'. Herbal keywords included 'herbal medicine', 'medicinal plant', 'natural products', 'phytomedicine' and 'phytotherapy'. 'antiinflammatory effect' combined with the words 'interleukin-6 (IL-6)', 'interleukin-8 (IL-8)', 'interleukin-1β (IL-1β)', and 'tumor necrosis factor α (TNF-α)'. XO inhibitory effect, uricosuric action, and anti-inflammatory effects were the key outcomes. Numerous agents derived from plants have anti-gout potential. In in vitro studies, flavonoids, alkaloids, essential oils, phenolic compounds, tannins, iridoid glucosides, and coumarins show the potential of anti-gout effects by their XO inhibitory action, while lignans, triterpenoids and xanthophyll are acting through their anti-inflammatory effects. In animal studies, essential oils, lignans, and tannins show dual effects including reduction of uric acid generation and uricosuric action. Alkaloids reveal inhibit uric acid generation, show anti-inflammatory effects, or a combination of the two. Phenolic compounds and flavonoids inhibit uric acid production, show uricosuric anti-inflammatory effects. In the rare human studies, colchicine from Colchicum autumnale showed anti-inflammatory effects while for other plant extracts, although revealing anti-gout potential, further phytochemical investigations are needed to identify their active constituents. Besides, the plants which give antioxidant activities are much potent in the management of gout and need to be further investigated. The current review is a detailed discussion of the potential of medicinal plants for treatment of gout.