Facile synthesis of cobalt-nickel oxide nanocomposites for trifunctional application towards antioxidant, anticancer and electrochemical performance

[Display omitted] •A new nanocomposite (CNC) appending NiO and Co3O4 was synthesized by facile and eco-friendly manner.•The synthesized CNC NPs used for energy storage applications.•The synthesized CNC possessed good electrochemical stability, reversibility and structural stability for energy storage.•The CNC acted as good radical scavenger for the series of radicals such as DPPH•, ABTS_+, NO_, OH•, O2– with the substantial activity.•The CNC showed promising apoptogenic nature with MM2 and HepG2 cancer cells. Transition metallic mixed oxides have received a lot of curiosity due to their exceptional electrochemical performance and incredibly low cost for hybrid supercapacitors. Herein, we report a facile synthetic approach of cobalt nickel oxide (CNC) composites from Carica papaya leaf extract. The synthesized mixed oxide composite was analyzed by various spectroscopic techniques (IR, UV–Vis, Powder XRD, SEM-EDAX, TEM and XPS). The electrochemical behavior of CNC was investigated by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) method in 2 M KOH solution. The composites exhibit specific capacitance of 289.28 F g−1 at 1 A g−1 demonstrating improved charge storage. The electrode retains 81 % of its specific capacitance from the initial value after repeated charge–discharge processes for 2000 cycles. In addition to the electrochemical studies, biological activities such as anti-oxidant and anti-cancer activities of the CNC were examined. The radical scavenging activity of CNC was assessed with different radicals such as DPPH•, ABTS+., NO–, OH•, O2– and the acquired results showed that the composites possessed substantial activity. Anticancer activity of CNC was studied against HepG2 and MM2 cancer cells and the CNC possessed significant activity with the IC50 value of 45.8 and 38.3 µg/ml respectively compared with the standard drug cisplatin. Further apoptogenic nature of the CNC was confirmed with DAPI staining assay.