Antioxidant, Brine Shrimp Lethality and Antimicrobial Activities of Methanol and Ethyl-Acetate Extracts of Citrus macroptera Montr. Fruit Using In vitro Assay Models

Aims: To study and evaluate In vitro antioxidant, brine shrimp lethality and antimicrobial activities of both methanol and ethyl-acetate extracts of Citrus macroptera Montr. Fruit (Family-Rutaceae).
Study Design: In vitro antioxidant, brine shrimp lethality and antimicrobial activities.
Place and Duration of Study: Department of Pharmacy, Jahangirnagar University, Savar, Dhaka-1342. The study was carried out from November 2013 to January 2014.
Methodology: In vitro antioxidant activities of the extracts were studied using DPPH radical scavenging assay, NO scavenging assay, total phenol, total flavonoid content, total antioxidant capacity, total tannin content, lipid peroxidation by TBA, lipid peroxidation in human erythrocyte cell, reducing power capacity and cupric reducing capacity assays. Lethality bioassay was performed on Artemia salina Leach nauplii. Antimicrobial activity was investigated by disc diffusion technique.
Results: Methanol extract showed better activity than ethyl acetate extract in DPPH, NO, lipid peroxidation by TBA, reducing power capacity assay, total phenol, total flavonoid and total antioxidant capacity assays while ethyl –acetate extract showed more potency than methanol extract in total tannin content, cupric reducing capacity and lipid peroxidation in human erythrocyte assays. In brine shrimp bioassay both extracts showed promising lethal activity but methanol extract was found to be more potent than ethyl acetate extract (χ2=39.874, P<0.0001). In disc diffusion technique among six bacterial species, ethyl acetate extract showed broad spectrum antimicrobial activity against two gram positive Bacillus sublitis and Staphylococcus aureus and one gram negative Escherichia coli.
Conclusion: The results demonstrate that methanol and ethyl-acetate extracts of C. macroptera fruit can be used as potential antioxidant, cytotoxic and antimicrobial agents. That is why extensive researches are necessary to search for active principles responsible for these activities.