Effect of different Vitis vinifera seed extracts on lactobacillus acidophilus and casei bacteria

Due to the limitations of chemical antimicrobial methods in the treatment of dental caries, the recent studies have focused on the use of plant-derived antibacterial agents to inhibit tooth decay bacteria. Therefore, the aim of this study was to investigate the effect of Vitis vinifera seed extract (VVSE) on Lactobacillus acidophilus and casei bacteria.

In this cross-sectional study, the VVSs were dried, the obtained powder was poured into separate containers to prepare aqueous, alcoholic and acetone extracts, and the desired solvents were added. After being placed in the shaker incubator and passing through the filter paper, the solvents were transferred to the plates.After cultivation of Lactobacillus acidophilus and casei bacteria in tubes containing Mueller Hinton Broth, the aqueous, alcoholic and acetone extracts were added to them. A tube with no extract was considered as control. The resulting samples were cultured on chocolate agar medium. The initial concentrations (2, 4 and 8 μg/ml) were not able to inhibit bacterial growth; thus, the higher concentrations were assessed to determine minimum inhibitory concentration (MIC). The data were analyzed using SPSS-17 via Chi-square, Mann-Witney and Kruskal-Wallis. Moreover, α =0.05 was considered significant.

The MIC of aqueous extract was 32 and 64 μg/ml for Lactobacillus acidophilus and casei, respectively. The alcoholic extract stopped the growth of both bacteria at concentration of 128 μg/ml. The MIC of acetone extract was 64 and 128 μg/ml for Lactobacillus acidophilus and casei, respectively. So, aqueous extract was more effective than alcoholic one (p=0.016). However, there was no significant difference between alcoholic and acetone (p=0.1267) as well as aqueous and acetone (p = 0.061) extracts.

Antibacterial activity of aqueous extract was more than that of alcoholic and acetone extracts. Alcoholic and acetone extracts had no significant difference in inhibition of bacterial growth. Therefore, it is possible to use aqueous extract of VVSs to control caries.