Optimization of Microwave-assisted Extraction Process of Anthraquinones from Aloe vera by Response Surface Method and Analysis of Its Antioxidant Activity

In order to improve the extraction amount of anthraquinones from Aloe vera peel, this study used microwave-assisted extraction method to extract anthraquinones from Aloe vera, and investigated the effects of different ethanol concentrations, extraction time, microwave power, and material-to-liquid ratio on the extraction, and carried out response surface optimization of the extraction process based on single-factor experiments, and studied the in vitro antioxidant properties of Aloe vera anthraquinones by its effects on DPPH radical scavenging ability, ABTS⁺ radical scavenging ability, superoxide anion radical scavenging ability, iron ion reducing ability and lipid peroxidation inhibiting activity. The results showed that the optimal conditions for the extraction of Aloe vera anthraquinones by microwave were: Ethanol concentration of 80%, extraction time of 60 s, microwave power of 406 W, and material-to-liquid ratio of 1:19 g/mL. The extracted amount of Aloe vera anthraquinones was 12.29 mg/g, and the in vitro antioxidant IC₅₀ values were 0.431±0.003, 0.400±0.005, 0.443±0.012, 0.417±0.007 and 0.441±0.008 mg/mL, respectively.