The Cytotoxic and Inhibitory Effects of Plant Derivatives on Candida albicans Biofilms: A Scoping Review.

Candida albicans infections are related to biofilm formation. The increase in antifungal resistance and their adverse effects have led to the search for therapeutic options as plant derivatives. This scoping review aims to identify the current status of in vitro research on the cytotoxicity and inhibitory effects of plant derivatives on C. albicans biofilms. In this study, PRISMA items were followed. After recognition of the inclusion criteria, full texts were read and disagreements were resolved with a third party. A risk of bias assessment was performed, and information was summarized using Microsoft Office Excel. Thirty-nine papers fulfilling the selection criteria were included. The risk of bias analysis identified most of the studies as low risk. Studies evaluated plant derivatives such as extracts, essential oils, terpenes, alkaloids, flavonoids and polyphenols. Some studies evaluated the inhibition of C. albicans biofilm formation, inhibition on preformed biofilms or both. The derivatives at concentrations greater than or equal to those that have an inhibitory effect on C. albicans biofilms, without showing cytotoxicity, include magnoflorin, ellagic acid, myricetin and eucarobustol from Eucalyptus robusta and, as the works in which these derivatives were studied are of good quality, it is desirable to carry out study in other experimental phases, with methodologies that generate comparable information.

Antimicrobial activity of Cymbopogon citratus (Poaceae) on Streptococcus mutans biofilm and its cytotoxic effects

Resumen La caries dental, es una patología de origen multifactorial y actualmente los productos naturales son un tratamiento alternativo eficiente. El trabajo buscó evaluar la actividad antimicrobiana del aceite esencial de tres sustancias (Cymbopogon citratus y los componentes citral y mirceno) contra Streptococcus mutans ATCC UA159, así como su citotoxicidad sobre queratinocitos y fibroblastos humanos. A través de Microscopía Electrónica de Barrido, se observó la morfología típica de S. mutans, y una formación característica de polisacáridos, con una disposición más estructurada a las 48 h. El efecto de viabilidad bacteriana contra S. mutans en biofilms se evaluó a través de la exposición a las tres sustancias mediante el uso de la técnica de alto rendimiento MBEC, a concentraciones de 1, 0.1 y 0.01 μg/ml y clorhexidina como control positivo. La citotoxicidad de los compuestos se evaluó sobre queratinocitos y fibroblastos, mediante la técnica de reducción de MTT, utilizando 0.5 mM de H2O2 como control de muerte celular (control negativo) y etanol 1 % como control del vehículo (control positivo). Las tres sustancias evaluadas, tuvieron efectos sobre la viabilidad bacteriana de S. mutans con una mortalidad entre 74 y 96 %, sin diferencia significativa entre ellos (P > 0.393); adicionalmente, no fue evidente la citotoxicidad sobre queratinocitos y fibroblastos en un tratamiento de 24 h. Las sustancias evaluadas mostraron efectos antimicrobianos significativos; por lo tanto, estos deben estudiarse más a fondo como posibles coadyuvantes para prevenir la caries dental que causa efectos adversos menores.(AU)

Abstract Dental caries is a pathology of multifactorial origin and currently natural products are an efficient alternative treatment. The work sought to evaluate the antimicrobial activity of the three substances (Cymbopogon citratus essential oil and the citral and myrcene components) against Streptococcus mutans ATCC UA159, as well as their cytotoxicity on keratinocytes and human fibroblasts. Through Scanning electron microscopy, the typical morphology of S. mutans was observed and, a characteristic formation of polysaccharides, with more structured arrangement at 48 h. The bacterial viability effect against S. mutans on biofilms was evaluated through exposure to the three substances by using the MBEC technique-high-throughput at concentrations of 1, 0.1, and 0.01 µg/mL and chlorhexidine as positive control. The cytotoxicity of the compounds was evaluated on keratinocytes and fibroblasts through the MTT reduction technique, using 0.5 mM H2O2 as cell-death control (negative control) and ethanol 1 % as vehicle control (positive control). The three substances evaluated had effects on the bacterial viability of S. mutans with mortality between 74 and 96 %, without significant difference among them (P > 0.393); additionally, no cytotoxicity was evident on keratinocytes and fibroblasts in a 24 h treatment. The substances evaluated showed significant antimicrobial effects; hence, these should be studied further as potential co-adjuvants to prevent dental caries that cause minor adverse effects.(AU)

In silico search of inhibitors of Streptococcus mutans for the control of dental plaque.

Biofilm is an extremely complex microbial community arranged in a matrix of polysaccharides and attached to a substrate. Its development is crucial in the pathophysiology of oral infections like dental caries, as well as in periodontal, pulp, and periapical diseases. Streptococcus mutans is one of the most effective microorganisms in lactic acid production of the dental biofilm. Identifying essential Streptococcus mutans proteins using bioinformatics methods helps to search for alternative therapies. To this end, the bacterial genomes of several Streptococcus mutans strains and representative strains of other cariogenic and non-cariogenic bacteria were analysed by identifying pathogenicity islands and alignments with other bacteria, and by detecting the exclusive genes of cariogenic species in comparison to the non-pathogenic ones. This study used tools for orthology prediction such as BLAST and OrthoMCL, as well as the server IslandViewer for the detection of pathogenicity islands. In addition, the potential interactome of Streptococcus mutans was rebuilt by comparing it to interologues of other species phylogenetically close to or associated with cariogenicity. This protocol yielded a final list of 20 proteins related to potentially virulent factors that can be used as therapeutic targets in future analyses. The EIIA and EIIC enzymatic subunits of the phosphotransferase system (PTS) were prioritized, as well as the pyruvate kinase enzyme, which are directly involved in the metabolism of carbohydrates and in obtaining the necessary energy for the microorganism's survival. These results will guide a subsequent experimental trial to develop new, safe, and effective molecules in the treatment of dental caries.