Antibacterial efficacy of methanolic extract of molave (Vitex parviflora A. Juss) leaves against Streptococcus mutans

Abstract

Background:  Antibacterial drugs are used for suppressing harmful bacteria. However, some are reported to have side effects which led researchers to investigate plants with antimicrobial properties as potential alternatives. One such indigenous plant is the Vitex parviflora A. juss, “molave” or “mulawin” tree.

Objective:  This study determined and compared the antibacterial efficacy of 50 mg/ml and 100 mg/ml
concentrations of fresh local molave leaves methanolic extract with 0.12% chlorhexidine, distilled water, and 95% methanol on growth inhibition of S. mutans.

Methodology:  Five hundred grams of fresh molave leaves were collected and subjected to methanolic
extraction. In vitro antimicrobial susceptibility test by disk diffusion of 50 mg/ml and 100 mg/ml molave
extract concentrations, 0.12% chlorhexidine, distilled water, and 95% methanol on 18 Mueller-Hinton agar
(MHA) plates inoculated with S. mutans was done. For cost-efficiency, the total sample size of 80 plates was reduced by placing 5 test groups in one plate divided into five portions done in 18 replicates. After 48 hours of incubation in anaerobic conditions, resulting zones of inhibition were measured. Data were analyzed through one-way ANOVA and Bonferroni tests.

Results: The mean diameter of inhibition zones produced by 100 mg/ml and 50 mg/ml concentrations of molave methanolic leaves extract and 0.12% chlorhexidine was 15.78 mm, 11.63 mm, and 21.44 mm, respectively. Distilled water and 95% methanol did not inhibit bacterial growth. The 100 mg/ml concentration has stronger antibacterial properties than the 50 mg/ml.

Conclusion: The Vitex parviflora A. Juss methanolic leaves extract has the ability to inhibit the growth of S. mutans in vitro. Both concentrations were relatively weaker compared to chlorhexidine.