Phytochemical Components, Antioxidant Properties, Antimicrobial Effects, and Insecticidal Prospects Against the Black Bean Aphid (<i>Aphis fabae</i> Scop.) of <i>Olea europaea</i> L. Leaves Extracts from Morocco

Abstract

The escalating phenomenon of bacterial resistance to antibiotics over time, coupled with the conse-quential detrimental effects of oxidative stress on cellular aging, and the usage of pesticides with vary-ing degrees of toxicity, thereby impacting both human health and the environment, represents a pressing global concern. Consequently, researchers are compelled to identify novel biomolecules de-rived from plants and their derivatives that possess antibacterial, antioxidant, and insecticidal proper-ties. The olive tree (Olea europaea L.), a fruit-bearing tree within the Oleaceae family, characterized by its olives, has been cultivated for millennia, particularly in Mediterranean regions, with its leaves being primarily employed for their multifarious therapeutic attributes. In this investigation, extracts were procured from olive leaves through employment of the Soxhlet apparatus, followed by the quantifica-tion of total polyphenols and flavonoids. The assessment of the antioxidant potential of these extracts was conducted using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The antibacterial efficacy was evaluated via the disk diffusion method against six pathogenic bacterial strains, namely Staphylococcus aureus, Escherichia coli, Acinetobacter baumannii, Salmonella sp, Klebsiella pneumoniae, and Pseudo-monas aeruginosa. Additionally, the in vitro aphicide activity of Olea europaea L. extracts were investi-gated at concentrations of 0.5%, 1%, 1.5%, 2%, and 2.5% against the black bean aphid, Aphis fabae Scop. The findings of this study suggest that olive leaf extracts exhibit robust antioxidant properties and dis-play modest antibacterial activity against pathogenic agents. Hence, these extracts are strongly en-dorsed for their potential role as eco-friendly antioxidants, and owing to their modest yet efficient in-sect-repelling attributes, they can be utilized as a sustainable, low-impact insecticide in the ecological engineering approach to controlling black aphids in bean crops. Therefore, the utilization of olive tree-derived extracts is encouraged.