Optimization of polyphenol extraction from D. Don leaf using supercritical CO by response surface methodology.

Unlabelled: In this study, an eco-friendly supercritical carbon dioxide (SC-CO) extraction of polyphenolic compounds from leaf was optimized to achieve the highest extraction yield with maximum total phenolic content (TPC) and minimum IC50. The central composite design was used to establish an experimental design for RSM. The effect of the pressure, temperature, carbon dioxide flow rate, and co-solvent amount was scrutinized using variance analysis (ANOVA). Under optimized condition (25.13 MPa, 47.53 °C, 14.47 g/min, and 2.43%), the experimental data (yield of extraction: 4.38%, TPC: 84.31 mg GAE/g, and IC50: 41.94 µg/mL) showed good agreement with the predicted values (yield of extraction: 4.53%, TPC: 83.37 mg GAE/g, and IC50: 40.2 µg/mL). Nine polyphenolic compounds: gallic acid, caffeic acid, ferulic acid, vanillic acid, p-coumaric acid, quercetin, myricetin, kaempferol, and rutin were analyzed in SC-CO extract using HPLC. SC-CO extraction was more selective for ferulic acid, myricetin, and quercetin extraction. The study results revealed that SC-CO extract had significant antibacterial activity against eight bacterial strains.

Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03358-1.