Effect of Cadmium Application on Antimicrobial, Antioxidant and Total Phenolic Content of Basil Genotypes

Background: Exposure to heavy metals leads to increase in reactive oxygen species. Plants have many strategies to counteract the toxic effects of heavy metal stress by activating certain intermediary metabolic activities and making physiological adjustments. Objective: This study was designed to determine total phenolic contents and antimicrobial and antioxidant activities of eight Ocimum basilicum L. genotypes grown in a soil exposed to cadmium at different levels. Methods: Total phenolic contents were calculated as gallic acid equivalent. Antioxidant activity was studied based on DPPH free radical scavenging activity. Antimicrobial activity was determined by disc diffusion method against several microorganisms. Results: The highest antimicrobial activity was observed in the case of genotype 5 against Bacillus subtilus with the inhibition diameter value as 18.50 mm for basil grown at Cd free soil. This value just decreased to 17.57 mm at the conditions with 40 mg/kg Cd. Depending on increase at cadmium dose, the best grade increase in antimicrobial activity was also observed against B.subtilus for genotype 7. Total phenolic content and DPPH radical scavenging activity values were also increased with the Cd application at low doses. At very high doses of Cd a little decrease was observed for these values. Both of the phenolic content values and DPPH scavenging activities reached their maximum values for genotypes 1,7 and 8 grown at soil exposed to 20 mg/ kg Cd. Conclusion: Although cadmium is toxic, known beneficial properties of the basil samples have not deteriorated. These improved results are due to resistance of the basil plant to survive on adverse conditions.