Microwave-assisted extraction of triterpenoid from Abelmoschus sagittifolius (Kurz) Merr roots using deep eutectic solvents

A green and efficient method was developed for extracting triterpenoids from Abelmoschus sagittifolius roots using microwave-assisted extraction (MAE) combined with a choline chloride–citric acid-based deep eutectic solvent (DES). Optimization by response surface methodology identified optimal conditions (365 W, 46 min, 40 mL/g), yielding 39.8 mg/g of triterpenoids, in close agreement with the predicted value (39.5 mg/g). This yield was significantly higher than those obtained by ethanol-based MAE (32.69 mg/g) and Soxhlet extraction (28.14 mg/g). SEM analysis revealed marked cell wall disruption in DES–MAE-treated samples. The extract exhibited strong antioxidant activity (84.56% DPPH and 96.67% ABTS at 0.55 mg/mL) and notable tyrosinase inhibition (IC₅₀ ≈ 0.17 mg/mL), outperforming conventional extracts. GC–MS analysis identified 18 bioactive compounds, predominantly triterpenoids. Overall, DES–MAE represents a sustainable approach for producing triterpenoid-rich extracts for food, cosmetic, and pharmaceutical applications.