Utilization of quercetin and quercetin glycosides from onion ( Allium cepa L.) solid waste as an antioxidant, urease and xanthine oxidase inhibitors

Antioxidant, anti‐inflammatory, and enzyme inhibitory activity of natural plant flavonoids and their synthesized derivatives

“…[36] Synthetic as well as naturally occurring flavonoid derivatives have many interesting pharmacological activities including antitumor, antioxidant, anti-inflammatory, antidiabetic, and enzyme inhibitory activities. [23,25] Several studies have reported that flavonoids were important natural antioxidants, which basically associate with curing of various diseases and disorders including cancer, diabetes, gout, urolithiasis, obesity, and other diseases associated with ageing. [26,37] There is urgent need for the discovery of efficient and safe inhibitors against the XO and urease, which are mainly associated with several pathological conditions for the development of various diseases including gout and urolithiasis.…”

“…[26,37] There is urgent need for the discovery of efficient and safe inhibitors against the XO and urease, which are mainly associated with several pathological conditions for the development of various diseases including gout and urolithiasis. [23] The naturally occurring phenolics and flavonoids occurred in a great variety of fruits, vegetables, and medicinal plants were found to be promising potent inhibitors against urease and XO to control their activity in human. [25,26] The results and data obtained in this study will definitely help the researcher to explore the development of synthetic flavonoid derivatives for the treatment of wide range of diseases associated with ROS like inflammation, gout, and Alzheimer's disease.…”

“…This assay was performed according to method described by Nile et al [23] Quercetin was used to obtain a calibration curve (25 and 100 M) for further calculations. The increase in absorbance was directly correlated to increase in reducing power.…”

“…[29] The antioxidant activity mainly depends on the type and structure of phenolic compounds as well as the solvent used for activity. [23] …”

“…[18,19] Phenolics and flavonoids may acts as potent inhibitors against the metabolic enzymes such as cyclooxygenase, XO, and lipoxygenase. [23] Thus, the phenolics and flavonoids may play an essential role in the inhibition of XO and these XO inhibitors and uricosuric agents are commonly used against the treatment and curing of inflammatory diseases and gouty arthritis. So the drug allopurinol is the drug of choice against XO activity;…”