Utilization of [Bmim]BF4-MAE on enhancement of γ-oryzanol extraction from rice bran and its tyrosinase inhibitory activity
Arif Arrahman, Efendy Sigalingging, Elsa Trinovita, Fadlina Chany Saputri, Abdul Mun’im
Abstract
This study investigated the effect of ionic liquid (IL)-microwave assisted extraction (MAE) on γ-oryzanol extraction from rice bran (Oryza sativa L.). The conditions included the concentration of IL, liquid (IL)/solid (sample) ratio, extraction time, and microwave power. The use of 1-butyl-3-methylimidazolium ([Bmim]BF4) as a selected solvent in IL-MAE method was developed for extraction of γ-oryzanol from rice bran. The Box-Behnken design on four factors with response surface methodology (RSM) was used to optimize the experimental conditions. The optimum conditions for the MAE were a [Bmim]BF4 concentration of 0.7 M, liquid/solid ratio of 15 mL/g, extraction time of 10 minutes, and 30% microwave power with a γ-oryzanol value of 0.41 mg/g. The experimental values agreed with those predicted by the RSM models. A microplate reader method was used to determine the IC50 value in tyrosinase inhibitory activity of the extract. An IC50 value of the extract obtained from IL-MAE was 1240 µg/mL. This study suggests that IL-MAE is suitable for the extraction of γ-oryzanol from rice bran and that under the optimum conditions the extract has low activity as a tyrosinase inhibitor.