Subcritical Water Extraction for Selective Recovery of Phenolic Bioactives from Kānuka Leaves

This study investigated the selective recovery of antioxidant compounds from kānuka leaves using subcritical water extraction (SWE) at different extraction temperatures (150 to 210) °C, time (0 to 40) min, and solid-to-solvent ratio, SSR (15 to 35) g/L. The maximum total phenolic and flavonoid content in the kānuka leaf extracts were (167.93 ± 2) mg GAE/g dw and (405.4 ± 8.47) mg QE/g dw, respectively. These amounts were obtained using SWE at 170 °C for 20 min with SSR of 15 g/L; the extracts also showed the highest antioxidant activity. Eight compounds were identified, including gallic acid, quercetin, and catechin as major compounds. In comparison with conventional ethanol extraction, SWE proved to be a more effective alternative for extraction of bioactive compounds. The results indicate the potential of SWE for the production of high-quality plant extracts from kānuka leaves.Graphical abstract
Source: The Journal of Supercritical Fluids - Category: Chemistry Source Type: research