Chemical Composition, Antioxidant and Cytoprotective Potentials of Leaf Extracts: A Comparison of Supercritical Fluid and Conventional Extraction Methods.

The leaves of (CP) are rich in natural antioxidants. has traditionally been used to treat various ailments, including skin diseases. This study aims to decipher the antioxidant effects and phytochemical content of different CP leaf extracts (CPEs) obtained using supercritical carbon dioxide (scCO) and conventional extraction methods. The antioxidant activities of CPEs were evaluated by cell-free (1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric-reduced antioxidative power (FRAP)) and cell-based (HO) assay. Both leaf scCO extract with 5% ethanol (CPSCE) and leaf scCO extract (CPSC) exhibited stronger DPPH radical scavenging activity than conventional extracts. In the FRAP assay, two hydrophilic extracts ( leaf ethanol extract (CPEE) and freeze-dried leaf juice (CPFD)) showed relatively stronger reducing power compared to lipophilic extracts. Cell-based assays showed that CPFD significantly protected skin fibroblasts from HO-induced oxidative stress in both pre-and post-treatment. CPEE protected skin fibroblasts from oxidative stress in a dose-dependent manner while CPSCE significantly triggered the fibroblast recovery after treatment with HO. GC-MS analysis indicated that CPSCE had the highest α-tocopherol and squalene contents. By contrast, both CP hydrophilic extracts (CPEE and CPFD) had a higher total phenolic content (TPC) and rutin content than the lipophilic extracts. Overall, CPEs extracted using green and conventional extraction methods showed antioxidative potential in both cell-based and cell-free assays due to their lipophilic and hydrophilic antioxidants, respectively.