Improvement and Optimisation of Green Ultrasound‐Assisted Extraction for Sinapic Acid Content and Lipase Inhibition From Caucasian Whortleberry (<i>Vaccinium arctostaphylos</i> L.) by Box–Behnken Design

ABSTRACT Caucasian whortleberry ( Vaccinium arctostaphylos L.) is a beneficial natural source for obesity due to its rich content of phenolic compounds. It has been shown that phenolic compounds have antiobesity properties through a variety of molecular mechanisms. The goal of the current study was to identify the optimal conditions of green ultrasonic extraction (UAE) for Caucasian whortleberry via phenolic compounds and lipase inhibition. The experimental design was carried out using the response surface methodology (RSM) based on the Box–Behnken design (BBD) to detect optimum conditions of ultrasonic extraction. Three levels of three independent variables were incorporated into the BBD: ethanol concentration, temperature and time. RP‐HPLC analysis was utilised to quantify the phenolic content, and the spectroscopic method was used to evaluate the lipase inhibitions. Quadratic response surface models were suggested according to the results of the BBD model adequacy test ( p &lt; 0.0001) performed by multiple regression analysis. The data showed that the sinapic acid concentration and lipase inhibition are significantly impacted by the extraction conditions. The optimal conditions for sinapic acid content and lipase inhibition were detected as 100% ethanol concentration, 60°C and 60 min. The highest sinapic acid content (13.66 mg/g dry extract) and lipase inhibition level (IC 50 = 66.22 μg/mL) with desirability of 0.8583 resulted under optimal conditions. In comparison with the conventional extraction method, optimal conditions resulted in a notable rise of 57.01% for sinapic acid content and a substantial increase of 53.12% for lipase inhibitory effect. These optimal conditions mediated more sinapic acid content and lipase inhibitor activity can be suggested for the development of food supplements or herbal medicine with Caucasian whortleberry.