UHPLC-DAD-MS/MS phytochemical profiling of Geranium robertianum L. herba extract obtained by ultrasound-assisted extraction

Abstract

This study aimed to investigate the polyphenolic profile of Geranium robertianum L. herba using ultrasound-assisted extraction (UAE) followed by UHPLC-DAD-MS/MS analysis. The extraction was performed with 38% polyethylene glycol (PEG) in water as solvent, under optimized conditions (1:10 w/v ratio, 60 W, 50 °C, 45 min). The qualitative analysis revealed a chemically diverse extract, rich in phenolic compounds, particularly ellagitannins and flavonoids. Identified ellagitannins included brevifolincarboxylic acid, geraniin, HDDP-galloyl-glucose isomer, di-galloyl-HHDP-glucoside isomer, and a castalagin derivative. In the flavonoid fraction, compounds such as quercetin and its glycosides (quercetin-glucuronide, quercetin-3-O-glucoside, quercetin-3-O-rhamnoside, rutin), kaempferol derivatives, myricetin, myricitrin, luteolin-8-C-glucoside (orientin), and methylellagic acid rhamnoside were detected. Additionally, structurally complex flavonoids such as dihydroxy tetramethoxy flavones and sugar-conjugated quercetin forms further emphasized the phytochemical richness of the extract. The presence of these polyphenolic compounds suggests potential antioxidant, anti-inflammatory, antimicrobial, and photoprotective activities. These findings support the traditional use of G. robertianum and highlight its relevance as a source of multifunctional bioactive compounds. The results provide a basis for further pharmacological evaluation and indicate potential for future application in the development of phytopharmaceutical and cosmetic formulations.