Optimisation of the extraction conditions of polyphenol compounds fromPeperomia pellucidaand evaluation of antioxidant activityin vitro

Peperomia pellucida (Piperaceae) is a potential medicinal herb, with polyphenol compounds being its prominent ingredient.This ingredient has been shown to possess antioxidant properties, treat inflammation, gastric ulcers, and prevent cancer.To obtain the extract with the highest polyphenol content, this study was conducted to optimise extraction parameters affecting polyphenol compounds from Peperomia pellucida and evaluate its antioxidant activity.Based on the response surface methodology according to Design Expert 11.0 software, this research was conducted to optimise the four independent variables, such as ethanol concentration, material-solvent ratio, ultrasonic time, and number of ultrasonics.The strategy implementation method has established a method to describe the relationship between the reasonable polyphenol content and the priority level of variables, with a recovery coefficient R 2 of 0.8414 and p<0.0001.The model predicted the maximum polyphenol content achieved was 9.765 mg GAE/g dry matter at the factor values: ethanol concentration of 36%, material-solvent ratio of 1/12.93 g/ml, time of 26.53 mins, and number of ultrasound extractions of 3. Antioxidant activity with an average IC50 value of 382.91 g/ml.