Gnaphaloside A, a new chalcone, along with phenolic compounds in Pseudognaphalium affine exhibited noteworthy effects on xanthine oxidase

Cudweed is a common name of a numbers of species belonging to genus Gnaphalium and Pseudognaphalium , Asteraceae family. Recent literature has reported a potentially inhibitory effect on xanthine oxidase (XO -i ) of Pseudognaphalium afffine . In the course of study on species of cudweed grown in Vietnam, this work compared XO -i activity of two species P. affine and G. polycaulon , and investigated on phytochemicals from promising fractions. In vitro XO -i activity of methanolic extracts from different parts of use of the two plants was compared. Amongst tested samples, the methanolic extract of the flowers of P. affine exhibited potential activity (IC 50 of 35.34 μg/mL, comparing to 1.41 µg/mL of allopurinol). XO inhibitory activity-guided phytochemical analyse of the flowers of P. affine led to isolation of seventeen compounds. Among them, a new chalcone ( 1 ) was identified, together with sixteen known compounds, including one chalcone ( 2 ), two flavones ( 3 , 4 ), four flavonols ( 5 - 8 ), two flavanones ( 9 , 10 ), three caffeic acid derivatives ( 11 - 13 ), and four miscellaneous compounds ( 14 - 17 ). The structure of 1 was determined on the basis of its spectroscopic data to be 4,2’,4’-trihydroxy-6’-methoxychalcone-4’- O -β-D-(6’’( E) -caffeoyl)-glucoside, and it was named gnaphaloside A. Twelve of seventeen compounds, including the new chalcone, exhibited noteworthy inhibition on XO (with IC 50 value of 7.41-104.42 μM, comparing to 1.13 μM of allopurinol). Our findings unveiled the potential of phytoconstituents from P. affine grown in Vietnam to alleviate XO activity in related disorders [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ]. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany