Parvathy Chandra, Nikita Lolayekar, Aishani Baksi, Swagata Saha, Drishadvati Mukherjee, Manju Raman Nair
The aqueous extract of Ocimum sanctum Linn. demonstrated antibacterial effects against oral streptococci with acceptable cytocompatibility at lower concentrations and favorable pH modulation, supporting further translational investigation as a bioactive adjunct in oral mucosal ulcer management, with the understanding that such adjunctive use should complement, rather than substitute for, therapies directed at the primary immune-mediated etiology of RAS.
BACKGROUND: Ocimum sanctum Linn. (Tulsi/Holy Basil) possesses documented antibacterial, anti-inflammatory, and wound-healing properties. Recurrent aphthous stomatitis (RAS), the most common form of oral mucosal ulceration, is primarily an immune-mediated condition, with secondary microbial colonization potentially influencing lesion persistence; current therapies remain largely symptomatic.
OBJECTIVE: To evaluate the antibacterial efficacy, cytocompatibility, and pH-modulating effects of an aqueous extract of Ocimum sanctum Linn. against oral streptococci and human gingival fibroblasts (HGF) in vitro.
METHODS: An aqueous crude extract was prepared by maceration. Antibacterial activity against Streptococcus mitis (ATCC 6249) and Streptococcus sanguinis (ATCC 10556) was assessed by agar well diffusion, direct contact, and microbroth dilution assays (n = 6/group), with blinded outcome assessment. HGF viability (healthy and serum-stressed) was evaluated using the MTT assay (50-400 µg/mL; 24 h-5 days), with ≥70% viability (ISO 10993-5) considered cytocompatible. pH changes were recorded in a sucrose-containing system over 30 minutes. Data were analyzed using non-parametric tests (α = 0.05).
RESULTS: Agar well diffusion showed inhibition against S. mitis (9.67 ± 0.52 mm; p = 0.002) but not S. sanguinis. Direct contact and microbroth dilution assays revealed significant reductions in viable counts for both organisms (p < 0.01); minimum inhibitory concentration (MIC) was 50 µg/mL for both. HGF viability remained ≥70% at 50 µg/mL through 3 days in both conditions, whereas higher concentrations reduced viability. The extract raised environmental pH from 5.5 to approximately 6.0-6.5.
CONCLUSION: The aqueous extract of Ocimum sanctum Linn. demonstrated antibacterial effects against oral streptococci with acceptable cytocompatibility at lower concentrations and favorable pH modulation, supporting further translational investigation as a bioactive adjunct in oral mucosal ulcer management, with the understanding that such adjunctive use should complement, rather than substitute for, therapies directed at the primary immune-mediated etiology of RAS.