Optimization of extraction method for Kleeb Bua Daeng formula and comparison between ultrasound-assisted and microwave-assisted extraction

Abstract

Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) of the Thai herbal formula Kleeb Bua Daeng (KBD) were optimized separately and compared. A Box-Behnken design with response surface methodology was used to determine the effect of extraction time, temperature, solvent concentration, and material-to-solvent ratio for UAE and microwave power, extraction time, solvent concentration, and material-to-solvent ratio for MAE on response variables including extraction yield, total phenolic content (TPC), total flavonoid content (TFC), total carotenoid content (TCC) and total anthocyanin content (TAC) of KBD extracts. For UAE, the highest percentage extraction yield, TPC, TFC, TCC, and TAC of the extracts were 13.51%, 77.73 mg GAE/g extract, 35.40 mg QE/g extract, 17.27 mg β-carotene/g extract, and 0.33 mg cyanidin-3-glucoside/g extract, respectively. For MAE, the highest percentage extraction yield, TPC, TFC, TCC, and TAC were 18.95%, 476.61 mg GAE/g extract, 88.24 mg QE/g extract, 17.80 mg β-carotene/g extract, 0.97 mg cyanidin-3-glucoside/g extract, respectively. MAE extracts had higher yield, TPC, TFC, TCC, and TAC than UAE extracts and MAE appeared to be an efficient extraction method for this Thai herbal formula. This environmentally friendly extraction method could potentially be used to develop new KBD formulations with higher content of active ingredients.