The Antibacterial Activities of Lavandula angustifolia L., Mentha piperita L., and Ribes nigrum L. against Oral Bacteria, and Their Antioxidant Activities

Abstract

There is an expanding interest in medicinal and aromatic plants as a natural alternative to synthetic drugs, especially to antimicrobial agents due to the growing problem of antibiotic resistance. In recent years, a lot of reports have been published on the antimicrobial activity of the plant extracts. This study was used Lavandula angustifolia L., Mentha piperita L., and Ribes nigrum L. as plant materials. This study aims to test the plant extracts against oral bacteria. Its purpose is to produce directly comparable, quantitative, antimicrobial data, and in addition to containing very little information of the different extracts against oral pathogens. Disc diffusion method was studied for antimicrobial activity tests. Also, minimum inhibitory concentration (MIC) values were determined in this study. Additionally, the extracts were tested against stable 2,2-diphenyl-1-picryl-hydrazyl-hydrate• (DPPH•) free radicals for non-enzymatic antioxidant activity. This study was used Trolox (6-hydroxy-2,5,7,8-tetra-methyl chroman-2-carboxylic acid) as standard. The extracts showed different inhibition zones against bacteria. The methanol extract of Lavandula showed the highest inhibition zone against the oral pathogen MBKK5. The positive control was penicillin (10 μg). The lowest MIC value was taken at 6500 μg /ml concentration of the plant extracts. The highest DPPH• radical scavenging activity was found in Ribes nigrum extract as 36%. As a result, plant extracts have antibacterial and antioxidant potential.