Formulation of thermoreversible gel of cranberry juice concentrate: Evaluation, biocompatibility studies and its antimicrobial activity against periodontal pathogens

Abstract The present work aims to investigate the efficacy of thermoreversible gel of cranberry juice concentrate (CJC) as local drug delivery for the treatment of periodontitis. CJC was initially tested for its antimicrobial activities like MIC, MBC, antiadhesion, antibiofilm and time kill assay against the panel of organisms ( S . mutans (SM), E . faecalis (EF), A . actinomycetemcomitans (AA), P . gingivalis (PG), T . forsythia (TF)) responsible for periapical and periodontal infections. Antimicrobial activity of CJC showed MIC value of 50 mg/ml and MBC value of 100 mg/ml with desirable antiadhesion (83–90%) and antibiofilm activity (70–85%). CJC was evaluated for its biocompatibility using periodontal fibroblasts by cell based MTT assay and found to be nontoxic. Influence of CJC on periodontopathogen PG derived virulence factors ( fimA and kgp ) was studied using real time polymerase chain reaction (RT-PCR) technique wherein down regulation of selected genes demonstrated inhibitory effect against PG virulence factors. Thermoreversible gel of CJC was formulated by cold method using poloxamer 407 as thermosensitive polymer and carbopol 934 as mucoadhesive polymer and evaluated for its gelation temperature, viscosity, gel strength and mucoadhesive strength. Comparison of optimized thermoreversible gel of CJC (500 mg/ml) with commercially available chlorhexidine gluconate gel (0.2%) using agar well diffusion demonstrated equal zone of inhibition against SM, EF, AA, PG & TF. Hence the formulated thermoreversible gel of CJC could serve as a novel herbal alternative to currently available periodontal treatment modalities.