Medicinal plants of Pakistan and their xanthine oxidase inhibition activity to treat gout: a systematic review

Gout is the most prevalent form of arthritis that arises due to hyperuricemia. Xanthine oxidase inhibitors (XOI) are usually prescribed to treat gout. Although treatment options are available, these therapies are associated with side effects, and natural remedies may be proven helpful in this regard. This systematic review aims to present consolidated information on the xanthine oxidase inhibition potential of the plants located in Pakistan. An extensive literature review reveals that no such study that systematically summarizes existing data is currently available. The present study is registered with PROSPERO (ID: CRD42021247416) and performed according to PRISMA guidelines. Several databases were searched (from January 2000 to April 2021) for the keywords, including "hyperuricemia", "xanthine oxidase inhibitory activity", ?medicinal plants", "gout", "Pakistan", "in vivo", and "in vitro". The SYRCLE?s RoB tool was used to assess the risk of bias. Total 22 articles met the inclusion criteria. Following plants had higher XO inhibitory activity (>75%); Bryophyllum pinnatum, Zingiber officinale, Laggera aurita, Trachyspermum ammi, Tribulus terrestris, Trianthema triquetra, and Croton sparsiflorus. Numerous phytochemicals were also identified, and the followings had potent activity; acacetin 1 (11.92 ± 0.01 µM), ranuncoside (IC50 = 11.69 µM), chrysin 2 (IC50= 73.74 ± 0.02 µM), methyl-3,4,5-trihydroxybenzoate (IC50= 59.5 µM), costinone A (IC50= 90.3 ± 0.06 µM), and umbelliferone (IC50= 97.12 ± 0.01 µM). This study will provide beneficial insight into medicinal plants and serve as a reference for future studies on gout treatment. A rigorous pharmacological and clinical evaluation of medicinal plants is required to gauge their efficacy and safety.