Anti-Streptococcus mutans, anti-adherence and anti-acidogenic activity of Uvaria chamae P. Beauv.

ETHNOPHARMACOLOGICAL RELEVANCE: Streptococcus mutans a key pathogen, produces biofilm, acids and extracellular polysaccharides in the oral cavity; which leads to the development of dental caries. Control of these pathogenic markers can prevent dental caries. Uvaria chamae P. Beauv. is a medicinal plant traditionally used for many ailments including oral infections. Root, leaves and bark extracts has proven antibacterial activity including activity against caries causing S. mutans. However, its effect on the virulence properties of S. mutans, responsible for the development of dental caries, has not been studied. AIM OF THE STUDY: This study investigated the phytochemical constituents, anti-S. mutans, anti-adherence and anti-acidogenic activity of U. chamae root extract. MATERIALS AND METHODS: Extracts were prepared and phytochemical analysis was performed. Minimum inhibitory concentrations (MIC) were determined, and MIC and sub-MIC concentrations of the best solvent were selected for their effect on the virulence factors of S. mutans. The results were analysed using one-way ANOVA and Wilcoxon Rank Sum Tests. RESULTS: The dichloromethane extract, with proanthocyanidin as a major chemical constituent, produced an MIC of 0.02 mg/ml. At 6 h, exposure to 0.005, 0.01, and 0.02 mg/ml extract significantly reduced S. mutans adherence by 39, 59, and 77% respectively (p < 0.05). Uvaria chamae also significantly inhibited acid production in S. mutans at 10, 12, 14 and 16 h (p < 0.05). At ½ MIC, the plant extract caused remarkable downregulation of the virulence genes responsible for the adherence, biofilm formation, extracellular polysaccharide synthesis and acid production. CONCLUSIONS: This suggests that U. chamae extract may potentially be used to inhibit the proliferation of S. mutans and silencing the expression of pathology-related genes, which will prevent the development of dental caries.

Mezoneuron benthamianum inhibits cell adherence, hyphae formation, and phospholipase production in Candida albicans.

The aim of this study was to evaluate the phytochemical constituents, antioxidant, antifungal, and anti-virulence activities of traditionally used Mezoneuron benthamianum leaves. Extracts were prepared using acetone and methanol, and the preliminary phytochemical screening was performed. The antioxidant activity was studied using the DPPH method. Anti-Candida albicans activity was established and the effect on the germ tube and phospholipase production, as well as on the host cell adherence was assessed. The extracts showed the presence of anthraquinones, cardiac glycosides, flavonoids, reducing sugars, saponins, steroids, tannins, and terpenoids. Gallic acid and trans-resveratrol were among the predominant phytochemicals found in M. benthamianum. The crude extracts presented significantly higher antioxidant activity than the ascorbic acid standard. At 0.39 mg/mL, acetone extract inhibited the growth of Candida albicans. At lower concentrations (200-50 µg/mL), it significantly inhibited the adherence ability (up to 51%), formation of hyphae (up to 65%), and the production of phospholipase. In conclusion, at high concentrations, M. benthamianum kills C. albicans, and at lower concentrations, it can inhibit the virulence properties of this pathogen. This study on crude extract validates the traditional use of this plant. However, further research is required to establish the anti-virulence activity of the two compounds and their therapeutic potential.