Canadian Journal of Chemical Engineering, Vol.98, No.10, 2214-2226, 2020
Optimization of ultrasound-assisted extraction of bioactive compounds from B. forficata subsp. Pruinosa
Extracts containing bioactive compounds were obtained from Bauhinia forficata leaves by ultrasound-assisted extraction (UAE) with three different solvents (n-hexane, ethyl acetate, and ethanol) and were compared with those obtained by a conventional method (maceration). Box-Behnken experimental design was applied to examine and optimize the effect of the extraction temperature (40 degrees C-60 degrees C), power (20%-80%), and sample to solvent ratio (1:10 to 1:20 (w/v)) on the total phenolic content (TPC), total flavonoid content (TFC), and the ferric reducing antioxidant power (FRAP) of B. forficata leaf extracts. This experimental design generated second-order polynomial models, which accurately describe the experimental data, allowing the prediction of optimal conditions for the investigated responses. Optimal extraction was achieved under the following conditions: 80% power, temperature of 41 degrees C, and a 1:20 sample to solvent ratio. Under these conditions, the experimental yield was 8.33 +/- 0.32%, total phenolic content was 59.47 +/- 0.71 mg GAE center dot g(extract)(-1), total flavonoid content was 62.30 +/- 3.38 mg QE center dot g(extract)(-1), and the ferric reducing antioxidant power was 726.7 +/- 15.7 mu mol Fe(II)EQ center dot g(extract)(-1), which were close to the predicted values, which validated the models. The major compounds found in B. forficata extracts were tocopherols, phytol, heneicosane, and beta-Sitosterol.