Investigating the biological properties of carbohydrate derived fulvic acid (CHD-FA) as a potential novel therapy for the management of oral biofilm infections

Abstract

BackgroundA number of oral diseases, including periodontitis, derive from microbial biofilms and are associated with increased antimicrobial resistance. Despite the widespread use of mouthwashes being used as adjunctive measures to control these biofilms, their prolonged use is not recommended due to various side effects. Therefore, alternative broad-spectrum antimicrobials that minimise these effects are highly sought after. Carbohydrate derived fulvic acid (CHD-FA) is an organic acid which has previously demonstrated to be microbiocidal against Candida albicans biofilms, therefore, the aims of this study were to evaluate the antibacterial activity of CHD-FA against orally derived biofilms and to investigate adjunctive biological effects.MethodsMinimum inhibitory concentrations were evaluated for CHD-FA and chlorhexidine (CHX) against a range of oral bacteria using standardised microdilution testing for planktonic and sessile. Scanning electron microscopy was also employed to visualise changes in oral biofilms after antimicrobial treatment. Cytotoxicity of these compounds was assessed against oral epithelial cells, and the effect of CHD-FA on host inflammatory markers was assessed by measuring mRNA and protein expression.ResultsCHD-FA was highly active against all of the oral bacteria tested, including Porphyromonas gingivalis, with a sessile minimum inhibitory concentration of 0.5%. This concentration was shown to kill multi-species biofilms by approximately 90%, levels comparable to that of chlorhexidine (CHX). In a mammalian cell culture model, pretreatment of epithelial cells with buffered CHD-FA was shown to significantly down-regulate key inflammatory mediators, including interleukin-8 (IL-8), after stimulation with a multi-species biofilm.ConclusionsOverall, CHD-FA was shown to possess broad-spectrum antibacterial activity, with a supplementary function of being able to down-regulate inflammation. These properties offer an attractive spectrum of function from a naturally derived compound, which could be used as an alternative topical treatment strategy for oral biofilm diseases. Further studies in vitro and in vivo are required to determine the precise mechanism by which CHD-FA modulates the host immune response.

The Porphyromonas gingivalis hemagglutinins HagB and HagC are major mediators of adhesion and biofilm formation

“…Biofilm formation was assessed in P. gingivalis W83 and its derivatives as described previously (Sherry et al, 2013;Millhouse et al, 2014). Briefly, bacteria grown in Schaedler anaerobic broth for 48 h were used to prepare a suspension of 1 9 10 7 bacteria ml À1 in artificial saliva, which was composed of porcine stomach mucins [Sigma-Aldrich; 0.25% weight/volume (w/v)], sodium chloride (0.35% w/v), potassium chloride (0.02% w/v), calcium chloride dihydrate (0.02% w/v), yeast extract (0.2% w/v), lab lemco powder (0.1% w/v), proteose peptone (0.5% w/v) in ddH 2 O. Urea was diluted in PBS (40% w/v) and added to a final concentration of 0.05% (v/v).…”

“…Multi-species biofilms containing Streptococcus mitis NCTC12261, Fusobacterium nucleatum ATCC10596, Aggregatibacter actinomycetemcomitans OSM1123, and P. gingivalis (both W83 and hag mutants) were established using similar methods (Sherry et al, 2013;Millhouse et al, 2014). Mature multi-species biofilm biomass was measured using crystal violet.…”

“…Mature multi-species biofilm biomass was measured using crystal violet. Compositional analysis of the biofilms was assessed using quantitative PCR, as described previously (Sherry et al, 2013). Briefly, biofilms were sonicated in 1 ml of PBS for 10 min and DNA was extracted using the MasterPure Gram Positive DNA Purification Kit (Epicentre â , Cambridge, UK), following the manufacturer's instructions.…”

Studies on the binding of fulvic acid with transferrin by spectroscopic analysis

“…The pharmacological activities and biological activity of fulvic acid caused widespread concerns of the scholars [13]. Results obtained by Sherry et al revealed that fulvic acid was shown to possess broad-spectrum and antibacterial activity via investigating the biological properties of fulvic acid [14]. Yamada et al investigated the anti-allergic effect of fulvic acid and shown that FA may be useful for the treatment or prevention of allergic diseases [15].…”

Inhibition of microbial adhesion to plastic surface and human buccal epithelial cells by Rhodomyrtus tomentosa leaf extract

“…8 Medicinal plants have been studied by many workers as an alternative treatment for a number of infectious diseases, especially in oral diseases. [9][10][11][12] A wide variety of plants and their active constituents have been reported for many biological activities which included anti-adherent properties, [13][14][15][16][17][18] exclusively an inhibition on adherence ability and biofilm formation of oral pathogens. 15,[19][20][21] Downy rose myrtle, Rhodomyrtus tomentosa (Aiton) Hassk, is an evergreen shrub native to Southeast Asia 22,23 and currently has no economic value.…”