Characterization and in vitro cytotoxicity of phytochemicals from Aspilia africana obtained using green extraction techniques

Abstract In this study, we investigated the effect of different extraction techniques for the recovery of bioactive secondary metabolites from Aspilia africana (A. africana). Subcritical water extraction (SWE) at different temperatures (SWE140, SWE160, SWE180), and a combination of heating and agitation (HA) were compared with conventional solvent extraction using ethanol (80%, soxhlet). The extracts were characterized for the total phenolic contents (TPC), Total flavonoid contents (TFC), and phenolic compounds using HPLC-UV–VIS. The antioxidant activity by DPPH assay and anticancer activity against AGS, A549, and HeLa cell lines were also analyzed by MTT assay. Results showed that HA extracts contained the highest concentration of Gallic acid, TPC, TFC and exhibited the highest antioxidant activity with an IC50 nine times lower than that of ethanol extracts, followed by SWE. MTT assay showed that AGS cells were more sensitive to A.africana extracts (AAE), followed by A549 while HeLa showed little response to the treatments. HA exhibited the highest antiproliferative activity followed by SWE160. DAPI staining revealed that HA extracts induced a remarkable DNA breakage and nuclear condensation in treated cancer cells. This study revealed that HA and SWE are efficient techniques to recover extracts with antioxidant and anticancer potential from A. africana.