Phytochemical Screening, Antibacterial, Antifungal, and Anthelmintic Activity Against Plant Pathogens of two Algerian Plants: Pergularia tomentosa L. and Forsskaolea tenacissima L. from Oued Mzab (Northern Algerian Sahara)

Background: Plants are an abundant natural source of potential chemical compounds; they have been widely used in various industries, such as pharmaceuticals, cosmetics, and food. This work aims to study two Saharan medicinal plants by evaluating the activity of plant extract against bacterial and fungal plant pathogens as well as against the model nematode Caenorhabditis (C.) elegans. Methods: The antimicrobial activity of plant extracts against plants pathogen was assessed in a 96- well plate assay by calculating the percentage of inhibition of bacteria. The antifungal activity against plant pathogenic fungi was evaluated by the agar diffusion method, and inhibition was calculated by measuring the diameter of the inhibition zone. Anthelmintic activity was evaluated by calculating the average movement of C. elegans worms. Preliminary phytochemical screening was realized with HPTLC. Results: Hexane and ethyl acetate extract of Pergularia tomentosa showed broad-spectrum antimicrobial activity. This plant has the potential to act as a broad-spectrum antibacterial biopesticide. Hexane extract of Forsskaolea tenacissima exhibited good activity against one fungus. The extracts of Pergularia tomentosa showed good activity against Caenorhabditis elegans, and the extracts of Forsskaolea tenacissima exhibited a low activity. Preliminary phytochemical screening with HPTLC shows that both plants are rich in steroids and flavonoids. Conclusion: Our study shows that the studied plants may possess a broad-spectrum antibacterial effect with narrow-spectrum antifungal properties which can offer more sustainable crop protection with a much safer environmental and human health impact. Plant extracts that inhibited C. elegans could provide a starting point for the development of new anthelmintic drugs.