Comparative modeling of microwave and ultrasound assisted extraction of phenolics and berberine from Coptis teeta Wall. rhizomes†

Abstract

Coptis teeta rhizomes are a rich source of bioactive phytochemicals with significant applications in the food and nutraceutical industries. Standardized methods and solvent compositions are crucial to sustainably maximize bioactive yield while ensuring industrial feasibility. This study models and compares microwave (MAE) and ultrasound (UAE) assisted extraction of phenolics and berberine – the primary active alkaloid in Coptis teeta rhizomes. Previous studies on extracting phytochemicals from Coptis teeta have relied on the central composite design, which is limited in handling multiple independent variables. To address this limitation, a Box–Behnken design along with a response surface method was utilized, where independent variables included the solvent concentration (water : methanol), power level, extraction time, and solid–liquid ratio, and dependent variables were total phenolic content (TPC) and antioxidant activity. The results showed that for MAE, using 65% solvent concentration, 310 W power, 30 min extraction time, and 1 : 39 g mL⁻¹ solid–liquid ratio resulted in a TPC of 210.04 mg GAE 100 g⁻¹ and antioxidant activity of 98.57%. Whereas for UAE, 36% solvent concentration, 160 W ultrasound power, 10 min extraction time, and 1 : 78 g mL⁻¹ solid–liquid ratio resulted in a TPC of 251.11 mg GAE 100 g⁻¹ and 97.82% antioxidant activity. Berberine concentration in MAE extract was 212.18 ppm, whereas it was 162.96 ppm in UAE extract. While MAE yielded a higher berberine content, UAE was superior in extracting total phenolics. The findings provide a foundation for developing standardized methods and solvent compositions suitable for food and nutraceutical formulations.