Green Microwave-Assisted Extraction of Euphorbia guyoniana: Optimization, Metabolite Profile, and In Vivo Anti-Inflammatory Potential.

This study aimed to optimize microwave-assisted extraction of phenolic compounds from the undervalued traditional plant Euphorbia guyoniana (Boiss. & Reut.) using the central composite design of response surface methodology. The independent variables were extraction time, ethanol concentration in the extractive solvent, microwave power, and feed-to-solvent ratio while the dependent variables were total phenolic content (TPC) and total flavonoid content (TFC). Extract obtained by using the optimal extraction parameters was evaluated for its in vivo anti-inflammatory activity by the carrageenan-induced paw edema model and was subjected to RP-HPLC-PDA-ESI-MS analysis to investigate the presence of phenolic compounds. The optimal conditions for highest TPC (377.22 ± 5.42 mg GAE/g) and TFC (184.40 ± 1.18 mg QE/g) were obtained at an extraction time of 25 min, an ethanol concentration of 40.57%, a microwave power of 450 W and a feed-to-solvent ratio of 1:17.5. Optimal extract of E. guyoniana significantly higher inhibited carrageenan-induced inflammation with a concentration of 50 mg/kg (79.37%) when compared with the reference anti-inflammatory drug ibuprofen (43.06%). Finally, above the previously reported phenolic constituents, that is, quercetin and kaempferol derivatives, hydroxycinnamates have been identified for the first time in E. guyoniana plant extract.