Evaluation and Comparison of Antimicrobial and Anticancer Effects of Aqueous and Ethanolic Extracts of Viola Odorata

According to studies conducted on Viola odorata, many medical properties, including antimicrobial, anti-cancer, antioxidant, anti-inflammatory, etc. have been mentioned. Recent results have shown the strong cytotoxic effects of Viola odorata cycloidal compounds on different cancerous cell lines and bacteria. In addition, pathogen resistance has necessitated the study of new antimicrobial compounds. This study attempted to evaluate the antimicrobial and anticancer effects of aqueous and alcoholic extracts of Viola odorata.

Aqueous and alcoholic extracts of Viola were prepared using maceration method. After culturing Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, the minimum lethal concentration was measured by Minimum bactericidal concentration (MBC) method, and the minimum inhibitory concentration of different treatments was measured by minimum inhibitory concentration (MIC) method. To evaluate the cytotoxicity, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed on human foreskin fibroblasts (HFF) and A549 cells. The obtained data were statistically analyzed, and the results were considered significant with a P<0.05.

The results showed antimicrobial effects of Viola extract against tested bacteria, MIC 25mg/ml and MBC 50mg/ml in Escherichia coli, and MIC 50mg/ml and MBC 100mg/ml in Staphylococcus aureus were obtained. MTT test results showed that the cytotoxicity of ethanolic extract in both cell lines was higher than the aqueous extract. Moreover, the concentration of ethanolic extracts at 1000 and 1500mg/ml in A549 and HFF cell lines reduced the viability to 50%.

Aqueous and ethanolic extracts of Viola have an inhibitory effect on Gram-negative and positive bacteria and cancer cell proliferation. The lower side effects of Viola aqueous extract (VOA)/Viola ethanolic extract(VOE) on normal cells (HFF) have indicated that it can be considered as candidate for further studies in the field of new drug production.