Antibacterial Activity and Potential of a Combination Paste of Basil Leaf Extract (Ocimum basilicum L.) and Tomato (Solanum lycopersicum L.) against Streptococcus Mutans and Extrinsic Tooth Discoloration

Abstract

Introduction and Methods
Basil leaves (Ocimum basilicum L.) contain various bioactive compounds with antimicrobial activity, while tomatoes (Solanum lycopersicum L.) have been reported to exhibit potential in altering tooth color. However, evidence regarding the combined use of both extracts in a single paste formulation remains limited. This study aimed to evaluate the antibacterial activity of a paste formulation combining basil leaf and tomato extracts against Streptococcus mutans, as well as to evaluate color changes in teeth with extrinsic discoloration. This was a laboratory experimental study employing three combined paste formulations: K15+T30 (15% basil extract + 30% tomato extract), K30+T15 (30% basil extract + 15% tomato extract), and K30+T30 (30% basil extract + 30% tomato extract). Antibacterial activity against S. mutans was tested using the well diffusion method and assessed based on the diameter of the inhibition zone. Color change evaluation was conducted using human teeth subjected to extrinsic staining with a coffee solution. The specimens were brushed using an electric toothbrush for 30 seconds with each paste formulation and observed for seven days. Color changes were evaluated using the VITA Classical shade guide. Data were analyzed using the Shapiro–Wilk, Wilcoxon signed-rank, and Mann–Whitney tests with a significance level of p < 0.05.

Results
All three formulations demonstrated antibacterial activity against S. mutans. The mean inhibition zone diameters for K15+T30 and K30+T15 were 8.4 mm each, whereas K30+T30 produced the largest inhibition zone at 14.6 mm. The negative control did not produce an inhibition zone, while the positive control yielded an inhibition zone of 24.8 mm. The three formulations showed significant differences compared to the controls (p = 0.005). In the color change evaluation, K30+T15 exhibited the highest mean color change over seven days at 1.526. The color change in the K30+T15 group demonstrated significant differences from day one to day seven (p ≤ 0.003). However, significant color changes were also observed in the control group.

Conclusions and Recommendations
The combined paste of basil leaf and tomato extracts demonstrated antibacterial activity against S. mutans and showed potential in improving color changes in teeth with extrinsic discoloration. K30+T30 exhibited the highest antibacterial activity, while K30+T15 demonstrated the greatest and most consistent color change. These findings support the potential of the combined formulation as an active ingredient candidate for a multifunctional herbal toothpaste; however, further studies involving instrumental color measurement, safety evaluation, formulation stability, and clinical trials are required.

Contribution to Sustainable Development Goals (SDGs)
This research contributes to achieving the social development pillar of the Sustainable Development Goals (SDGs), specifically Goal 3 (Good Health and Well-being) and Target 3.b regarding the research and development of non-communicable disease medicines for oral and dental health.