Determination of Flavonoid Content in Tempuyung Leaf Extract (Sonchus arvensis L.) across Different Fractions

Abstract

Tempuyung (Sonchus arvensis L.) leaves are traditionally used as medicinal material and contain flavonoid compounds whose recovery may vary according to solvent polarity during extraction and fractionation. This study determines the total flavonoid content of the aqueous, ethyl acetate, and n-hexane fractions of S. arvensis leaf extract and identifies the fraction containing the highest concentration. A descriptive observational method was employed. The leaves were extracted by maceration with 96% ethanol, followed by liquid–liquid fractionation using distilled water, ethyl acetate, and n-hexane. Flavonoids were qualitatively identified using Mg-HCl and FeCl₃ reagents, while total flavonoid content was quantified by UV–Vis spectrophotometry using quercetin as the reference standard at a maximum wavelength of 421 nm. Qualitative screening confirmed the presence of flavonoids in the crude extract and all fractions. The aqueous, ethyl acetate, and n-hexane fractions contained 17.111 mg quercetin equivalents per gram (mg QE/g; 1.7111%), 91.887 mg QE/g (9.1887%), and 7.9333 mg QE/g (0.7933%), respectively. The ethyl acetate fraction therefore exhibited the highest total flavonoid content, followed by the aqueous and n-hexane fractions. These findings demonstrate that solvent polarity influences the distribution of flavonoids during fractionation and identify ethyl acetate as the most effective of the examined solvents for obtaining a flavonoid-enriched fraction of S. arvensis leaf extract. The study provides a practical basis for selecting an appropriate fraction for subsequent phytochemical and pharmacological investigation.