Extraction and analysis of total phenolics, flavonoids and marker iridoids from <i>Gentiana macrophylla</i> Pall roots: a natural source of bioactive agents

This study focused on the quality control (QC) of roots of <i>Gentiana macrophylla</i> Pall. from Hebei An-Guo Medicine Market, China. Plant roots were extracted using 70% aqueous ethanol with soxhlation and sonication extraction technologies. The extracts were then condensed, dried, and solubilised in methanol, ethanol, and water for chemical analysis. The sonication extract yielded higher amounts of total phenolics (33.12 mg/gDW) and flavonoids (17.59 mg/gDW) in ethanol compared to water and methanol. HPLC analysis showed a high concentration of gentiopicroside (588.48 μg/mL) in the ethanol fraction of the sonication extract, with loganic acid (283.58 μg/mL) and sweroside (9.49 μg/mL) in the water fraction. The soxhlation extract had lower concentrations of these compounds. The root extract (sonication extraction) of <i>G. macrophylla</i> Pall. demonstrated dose-dependent antioxidant (DPPH, NBTs, FRAP) and outstanding antibacterial activities against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i> at lower concentrations.