In vitro Screening for Antioxidant and Antimicrobial Properties of Three Lebanese Medicinal Plants Crude Extracts

Background: Despite its small geographic area, Lebanon is characterized by a natural wealth in medicinal plants. Lebanese flora has about 2600 species, where >100 are endemic and are used in traditional medicine for their therapeutic effects. Objective: To evaluate the antioxidant and antimicrobial activities of dichloromethane, methanol, and aqueous crude extracts of three Lebanese medicinal plants: Geranium robertianum, Asphodelus microcarpus, and Alcea setosa. Materials and Methods: The antioxidant activity of different crude extracts was determined using the free radical, 1,1‑diphenyl‑2‑picrylhydrazyl. Antimicrobial activity was evaluated in a plate‑hole diffusion assay against two Gram‑negative (Pseudomonas aeruginosa and Escherichia coli) bacterial strains, one Gram‑positive (Staphylococcus aureus) bacterial strain, and a fungal strain (Candida albicans). Results: Methanol and aqueous extracts of G. robertianum possessed high scavenging activity (Radical scavenging activity ( RSA) >85%) at 0.3 mg/mL followed by the extracts of A. microcarpus which showed a moderate activity. G. robertianum extracts exhibited good inhibition diameters against S. aureus growth. Conclusion: Obtained results give an overall view on the bioactivities of three Lebanese medicinal plants crude extracts.