Optimization of the ultrasonic-assisted extraction of trans-resveratrol and its glucoside from grapes followed by UPLC-MS/MS using the response surface methodology

Resveratrol with a high content in grapes has beneficial effects on inflammation, endothelial function, oxidative stress and cardiovascular and cerebrovascular diseases. Here, we propose a sensitive analytical method basing on the ultrasonic-assisted extraction followed by ultra-high performance liquid mass spectrometry to simultaneously determine trans-resveratrol (RES), trans-resveratrol 3-O-β-D-glucuronide, trans-resveratrol 4ʹ-O-β-D-glucuronide (R4G) in grapes. Single factor experiment and response surface methodology were used to optimize the pretreatment process of grape samples. The optimal conditions were as follows: extraction solvent-ethyl acetate, ultrasonic temperature 62 °C, ultrasonic time 20 min, ultrasonic power 90% and the volume of the extracted solvent 3500 μL. The method showed the good linearity (r ≥ 0.9917), the satisfactory intra-day (%RSD ≤ 11.3%) and inter-day precision (%RSD ≤ 14.5%) and low limit of quantification (0.1 μg/mL). This proposed method was successfully applied to determine RES, R3G, R4G in different grapes, achieving satisfactory recoveries (88.8–116.9%). Thus, this method established in this study is simple and time-saving, which will be helpful to the development and utilization of RES, R3G, R4G in grapes in food and pharmaceutical industries.