Antibacterial activity and cytotoxicity of different parts of Moringa oleifera Lam. plant from Ecuador

Medicinal plants are natural resources yielding valuable herbal products which are often used in the treatment of various ailments. Aqueous and methanol extracts from leaf, stem and root of Moringa oleifera Lam. were screened for their antibacterial activities while chloroform extracts from this plant parts were screened for brine shrimp lethality bioassay. The extracts were tested for their in vitro growth inhibitory effects against three pathogenic bacteria- Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus using the agar dilution and agar well diffusion methods. Mortality of the brine shrimp naupli (Artemia salina) was assessed by lethality bioassay and the mean lethal concentration (LC₅₀) values were obtained by probit analysis. The minimum inhibitory concentrations (MIC) of the aqueous and methanol extracts against the pathogenic bacteria were 25 mg/mL (leaf and root), 50 mg/mL (stem) and 12.5 mg/mL (leaf, stem and root) respectively. The methanol extracts produced zones of inhibition that were comparable to those produced by ciprofloxacin (20 µg). The LC₅₀ values of leaf, stem and root were found to be 16.43, 33.43 and 34.88 µg/mL respectively. The experimental results revealed that the leaf is more cytotoxic and showed highest activity against the three bacteria. Findings suggest that the different plant extracts possess potent growth inhibitory and cytotoxic potentials which validates their use in the treatment of microbial infections and as anti-tumor agent in ethnomedicine.