Extraction Optimization, Chemical Characterization , Xanthine Oxidase Inhibitory and Hypouricemic Activities for the Gout Treatment of the Extracts from Cosmos sulphureus Cav. flowers

Objectives Cosmos sulphureus Cav. has a rich history of traditional medicinal use in Southeast Asia, particularly for the treatment of diabetes, high blood pressure, inflammation and infections. This study aimed to optimize flavonoid extraction and evaluate the hypouricemic effects for the gout treatment of the extracts from the flowers of CS. Methods Extraction optimization was conducted using response surface methodology with a factorial design that included two variables – ethanol concentration (25%–70%) and solvent-to-material ratio (10-20 mL/g) - and three responses: extraction efficiency, total flavonoid content (TFC), and IC 5 0 values for xanthine oxidase inhibition. Toxicity studies followed the Guidelines for Preclinical and Clinical Trials of Traditional Medicine and Herbal Medicines issued by the Vietnam Ministry of Health as well as the OECD (2001) with minor modifications. The pharmacological activity was assessed in acute and chronic potassium oxonate–induced hyperuricemia models. Results The optimization CS extraction conditions were identified as percolation using 70% ethanol with a solvent-to-material ratio of 20 mL/g. The extraction process was successfully scaled up to 1 kg of raw material per batch, demonstrating its stability and applicability for further pharmacological studies. Chemical characterization confirmed the extract was rich in flavonoids, with coreopsin and luteolin identified as major constituents. In a model of acute and chronic hyperuricemia induced by potassium oxonate (i.p), the 250 mg/kg CS flower extract demonstrated uric acid-lowering effects similar to the reference drug allopurinol at 10 mg/kg. Conclusions These findings highlight the novelty of using Cosmos sulphureus Cav. as a potent natural source for anti-hyperuricemic agents, supporting its potential for pharmaceutical development.