α‐Glucosidase Inhibiting Chromene Derivatives from Ageratum conyzoides L. Essential Oil Extracted via NADES‐Assisted Hydrodistillation

Abstract

This work employed a green approach utilizing natural deep eutectic solvent (NADES)‐assisted hydrodistillation for EO extraction from the aerial part of Ageratum conyzoides. Out of seven eutectic combinations used, glycerol‐lactic acid (GLY:LA) (1:1) mixture significantly enhanced the yield from 0.78 mg/g (water as extraction media) to 1.00 mg/g. GC and GC‐MS analysis revealed that EOs mainly contain (E)‐β‐caryophyllene (15.2‐25.3%), (E)‐β‐farnesene (2.7‐8.2 %), and notably, precocene‐I (8.5‐18.0 %) and precocene‐II (31.8‐51.4 %), which varied significantly across different extraction media. Further column chromatography‐based purification of EO led to the isolation of two known chromene derivatives precocene‐I (1) and precocene‐II (2). Precocene‐I exhibited potent anti‐diabetic activity (IC50 0.26 mg/mL) compared to the standard drug acarbose. Among the EO samples, USK‐N7, which had the highest percentage of precocene‐I, showed the highest activity. The present study demonstrated the potential use of this weed plant as an anti‐diabetic agent.