Phytochemical screening and characterization of the antioxidant, anti-proliferative and antibacterial effects of different extracts of Opuntia ficus-indica peel

Abstract

Objectives: Opuntia ficus-indica peels need further investigations as they could contain multiple active molecules. Bioactive secondary metabolites are important for health maintenance and play a significant role in treating some common diseases. Hence, the present study analyzed the chemical composition and biological activities of the plant extract using in vitro models. Methods: The antioxidant assays were estimated in terms of DPPH radical scavenging; the chemical characterization is done in terms of total polyphenol and flavonoids, as well as HPLC characterization. The SRB assay was used for anticancer analysis whereas disc diffusion and minimum inhibitory concentration was determined to assess antimicrobial activity. Results: The content of total polyphenol (TPC) and flavonoids (TFC) differed significantly in Opuntia ficus-indica peel cyclohexanone extract (OFICE), Opuntia ficus-indica peel 70 % ethanol in water extract (OFI70EE), and Opuntia ficus-indica peel 70 % ethanol in water extract (OFI100EE)), with varying values of TPC and TFC. In HPLC analysis, there observed the presence of 8 phenolic and flavonoids compounds. Antioxidant analysis showed that OFICE has higher antioxidant activity. Bioassay based on MCF-7 showed that O. ficus-indica extracts significantly (p < 0.05) reduced cell viability of cancer cells at 400 µg/mL after 72 h of incubation time. Concerning the antibacterial activity, the cyclohexanone extract gave the highest antibacterial inhibition as compared to the other extracts, and the highest activity was recorded against Listeria monocytogenes. Also, the Opuntia ficus-indica peel extracts showed potential antiviral activity with the mean inhibition rates (39, 19, and 67.66 %) and (35, 16.66, and 54.66 %) against H5N1 and rotavirus respectively. Conclusion: Overall, the study confirms the antioxidant, antimicrobial and anticancer properties of the extract and further studies in animal models are necessary to validate their pharmacological applications.