Traditional processing techniques impacted the bioactivities of selected local consumed foods

•Cooking increased phenolic content of A. cepa, P. sajor- caju, M. oleifera leaves and pods.•Significant increase in antioxidant activity after cooking M. oleifera leaves and P. sajor-caju (p<0.05).•Antioxidant activity significantly decreased after cooking B. chinensis and M. oleifera pods (p<0.05).•Anti-proliferative properties of B. chinensis, P. sajor-caju and M. oleifera leaves against liver cancer cells was enhanced after cooking.•Optimizing cooking methods may play a key role in maximizing bioaccessibility of bioactive compounds.