A simple and efficient method has been developed for the simultaneous determination of eight flavonoids (orientin, hyperoside, rutin, myricetin, luteolin, quercetin, kaempferol, and apigenin) in Sonchus arvensis by high-performance liquid chromatography diode array detector (HPLC-DAD). This method was utilized to differentiate S. arvensis samples based on the plant parts (leaves, stems, and roots) and the plant’s geographical origin. The chromatographic separation was carried out on a reverse-phase C18 column by eluting at a flow rate of 1 mL/min using a gradient with methanol and 0.2% aqueous formic acid. In the optimum conditions, the developed method’s system suitability has met the criteria of good separation. The calibration curve shows a linear relationship between the peak area and analyte concentration with a correlation coefficient (r2) > 0.9990. The ranges for the analytes’ limits of detection and quantitation were 0.006–0.015 and 0.020–0.052 µg/mL, respectively. Intra-day and inter-day precision expressed in terms of RSD values were <2%, and the accuracy range based on recovery was 97–105%. The stability of all analytes within 48 h was about 2%. By combining HPLC-DAD fingerprint analysis with chemometrics, the developed method can classify S. arvensis samples based on the plant parts and geographical origin.

The leaves of Annona muricata (sirsak), Gynura procumbens (sambung nyawa), and Typhonium flagelliforme (keladi tikus) have been used as traditional medicines in Indonesia. This study aims to determine the antioxidant capacity and putatively identified phenolics from the leaves of three medicinal plants forementioned above. We used the DPPH (2,2-diphenyl-1-picrylhydrazyl) method for measuring radical scavenging (antioxidant assay) while the phenolics profiling was determined using UHPLC-Q-Orbitrap HRMS. The results showed that the percentage of radical scavenging activity of G. procumbens leaves extract in ethanol was higher than the other two plants. Phenolics profiling of the three medicinal plants was identified with 38 compounds belonging to flavones and flavanols hydroxycinnamic acid, and several other groups. The number of metabolites identified putatively was 12, 31, and 19 metabolites in the extracts of A. muricata, G. procumbens, and T. flagelliforme, respectively. The results confirmed the correlation between the phenolics presence and the antioxidant capacity of three plants used in this study.