Phytochemical Analysis, In Vitro Testing Of Antibacterial Properties, Anti- Inflammatory Activity, and Cytotoxicity of Aqueous and Dichloromethane Leaf Extracts Of Solanum Incanum and Tamarindus Indica

Abstract

Most communities use medicinal plants to treat and prevent various diseases. The use of the plants demonstrates the need to study the efficacy of selected medicinal plants. There is limited information on the antibacterial, anti- inflammatory activity, and cytotoxicity of Solanum incanum and Tamarindus indica leaves extracted using polar and less polar solvents. This study focused on analyzing phytochemicals present in aqueous and dichloromethane leaf extracts of the two plants and testing their antibacterial, anti- inflammatory, and cytotoxic properties. The phytochemical analysis was done using standard chemical tests followed by Gas Chromatography-Mass Spectroscopy of dichloromethane extracts. The antibacterial potency of the extracts was tested against Escherichia coli, Salmonella typhi, and Staphylococcus aureus using disc diffusion, Minimum Inhibitory Concentration, and Minimum Bactericidal concentrations. The anti- inflammatory potency of the extracts was tested using an Erythrocyte stabilization assay, while the toxicity of the extract was tested using brine shrimp lethality tests. The chemical test revealed that all the plant extracts contained flavonoids, tannins, saponins, phenols, and alkaloids. The T. indica dichloromethane and S. incanum water extracts had no glycosides, while anthraquinones were absent in all the plant extracts. The chromatographic analysis demonstrated the presence of flavonoids, phenols, and alkaloids in the selected plant extracts. The antibacterial activity revealed no significant difference in antibacterial activities between the two plants at α= 0.05. E. coli and S. Typhi were the most sensitive, while S. aureus was the least sensitive to the extracts. The Minimum

Inhibitory Concentration of T. indica ranged between 62.5 µg/mL and 125 µg/mL among the test organisms, while the Minimum Inhibitory Concentrations of S. incanum ranged between 62.5 µg/mL and 250 µg/mL. The Minimum Bactericidal Concentration of both plants ranged between 125 µg/mL and 500 µg/mL. The T. indica dichloromethane extracts had the highest stabilization, 57.64 ±13.90%, while S. incanum water extract had the lowest erythrocyte stabilization percentage, 19.06 ±14.43%. T. indica plant was more effective at 45.59 ±27.09% compared to S. incunum, 37.12 ±15.70%. The dichloromethane extracts of the two plants were more effective, 56.41 ±19.71% than water extracts at 26.30 ±12.53%. T. indica dichloromethane extract has the highest toxicity (LD50 of 113.57 µg/mL) while S. incanum was least toxic (LD50 of 2341 µg/mL). The assays demonstrated that the two plants are effective in treating bacterial infections and managing inflammation. In addition, the two plants were toxic at higher doses.