Quercetin as the primary xanthine oxidase inhibitor compound in Maclura tricuspidata leaf.

Maclura tricuspidata (MT) leaf demonstrated various health benefits, notably the inhibition of xanthine oxidase (XOD) activity, which is crucial in the management of hyperuricaemia and many diseases related to oxidative stress. This study aimed to identify the primary compound responsible for this inhibitory effect. Through a systematic investigation, MT leaf extracts were subjected to solvent-solvent partitioning using ethyl acetate, n-hexane, n-butanol, and dichloromethane. Further purification involved adsorption and desorption using Amberlite XAD-2 resin, followed by column chromatography on Silica Gel and Sephadex LH-20. The purified compounds were analysed using UPLC-QTOF-MS coupled with NMR spectroscopy. Our findings identified quercetin, a phenolic compound, as the most significant inhibitor of XOD activity in MT leaf, with an IC50 value of 212.92 µg/ml. This is the first report of purifying and identifying a single compound responsible for XOD inhibition in MT.

Pinus koraiensis Essential Oil Attenuates the Pathogenicity of Superbacteria by Suppressing Virulence Gene Expression.

In the quest to combat infections attributable to antibiotic-resistant superbacteria, an essential oil derived from the needles of Pinus koraiensis Sieb. et Zucc. (PKEO) has emerged as a promising solution. In this study, we demonstrate that PKEO can be used to inhibit the growth, glucose metabolite acidogenicity, and biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA). Quantitative PCR analysis provided direct evidence that PKEO reduces the mRNA expression of the accessory gene regulator A (agrA) and staphylococcal accessory regulator A (sarA), thereby indicating its inhibitory effect on pathogenic regulatory genes. Chromatographic analyses of PKEO identified terpene hydrocarbons as prominent essential oil constituents. These compounds, notably α-pinene, limonene, and ß-caryophyllene, have been established to have antimicrobial properties. Our findings indicate that an oil derived from P. koraiensis can effectively combat antibiotic-resistant strains by disrupting the pathogenicity regulatory system, thereby establishing PKEO as a promising candidate for the treatment of MRSA infections.