Glycerol-Water Green Solvent for Bioactive Metabolites Extraction from Ranunculus arvensis and Extraction Optimization by Response Surface Methodology

Ranunculus arvensis L. is a medicinal herb traditionally used for various purposes. The objective of the present research project was to find an effective and green method for obtaining bioactive natural products from it. Aqueous glycerol was employed as a green extracting medium, and the bioactive compounds were estimated as total flavonoid content (TFC) total phenolic content (TPC), antioxidant activity, and metal chelating activity (MCA). Response surface methodology (RSM) was applied to optimize the extraction process with temperature, time, and solvent (glycerol) concentration as input factors. The optimized conditions were 30 °C, 30 min, and 70% glycerol concentration at which the responses were TPC 7.15 mg gallic acid equivalents/g DW (dry weight), TFC 14.8 mg rutin equivalents/g DW, antioxidant 59.55%, and MCA 49.14%. The model was strongly supported by the validation study. The explored extraction process for bioactive natural products from R. arvensis is predictably applicable. Hence, 70% aqueous glycerol at almost room temperature and a minimum duration of 30 min can allow optimum extraction of phenolics, flavonoids, antioxidants, and metal chelators from R. arvensis.