The Beneficial Effect of Equisetum giganteum L. against Candida Biofilm Formation: New Approaches to Denture Stomatitis

Ethnopharmacological Potential of Phytochemicals and Phytogenic Products against Human RNA Viral Diseases as Preventive Therapeutics

RNA viruses have been the most destructive due to their transmissibility and lack of control measures. Developments of vaccines for RNA viruses are very tough or almost impossible as viruses are highly mutable. For the last few decades, most of the epidemic and pandemic viral diseases have wreaked huge devastation with innumerable fatalities. To combat this threat to mankind, plant-derived novel antiviral products may contribute as reliable alternatives. They are assumed to be nontoxic, less hazardous, and safe compounds that have been in uses in the beginning of human civilization. In this growing COVID-19 pandemic, the present review amalgamates and depicts the role of various plant products in curing viral diseases in humans.

Effect of denture liners surface modification with Equisetum giganteum and Punica granatum on Candida albicans biofilm inhibition

Aim: This study investigated the effect of denture liners surface modification with Equisetum giganteum (EG) and Punica granatum (PG) on Candida albicans biofilm inhibition supposing its usage as a sustained-release therapeutical delivery system for Candida-associated denture stomatitis. Materials & methods: C. albicans biofilm (SC5314 or ATCC 90028) was formed on soft liners superficially modified by a primer mixed to drugs at minimum inhibitory concentrations (0.100 g for EG and PG or 0.016 g for nystatin per ml of primer). After 24 h, 7 or 14 days, antibiofilm activity was evaluated by colony-forming unit counts. Results: Not all groups were equi-efficient to nystatin after 24 h and 7 days. After 14 days, EG and PG efficacies were not different from nystatin (almost 100% inhibition). Conclusion: The proposed protocol presents a promising option to allopathic drugs for Candida-associated denture stomatitis treatment.

Antioxidant-Rich Natural Raw Materials in the Prevention and Treatment of Selected Oral Cavity and Periodontal Diseases

Antioxidant-rich natural raw materials have been used for thousands of years in traditional medicine. In the past decade, there has been increasing interest in naturotherapy, which is a practice of using products with a natural origin. Natural products can be effective in the treatment and prevention of oral and dental diseases, among others. Such raw materials used in dentistry are characterized by antioxidant, anti-inflammatory, antibacterial, antiviral, antiedematous, astringent, anticoagulant, dehydrating, vitaminizing, and-above all-regenerative properties. Reports have shown that a relationship exists between oral diseases and the qualitative and quantitative composition of the microbiota colonizing the oral cavity. This review aimed to analyze the studies focusing on the microbiome colonizing the oral cavity in the context of using natural raw materials especially herbs, plant extracts, and isolated biologically active compounds as agents in the prevention and treatment of oral and periodontal diseases such as dental caries as well as mucosal changes associated with salivary secretion disorder. The present work discusses selected plant ingredients exhibiting an antioxidant activity with potential for the treatment of selected oral cavity and periodontal diseases.

Natural Compounds for Preventing Ear, Nose, and Throat-Related Oral Infections

Oral health is an essential element in maintaining general well-being. By preserving the complex equilibrium within the oral microbial community, commensal microorganisms can protect against extrinsic pathogenic threats. However, when an imbalance occurs, the organism is susceptible to a broad range of infections. Synthetic drugs can be administered to help the body fight against the fungal, bacterial, or viral burden. Nonetheless, they may produce undesirable consequences such as toxicity, adverse effects, and drug resistance. In this respect, research has focused on finding safer and more efficient alternatives. Particularly, increasing attention has been drawn towards developing novel formulations based on natural compounds. This paper reviews the plant-based, algae-based, and beehive products investigated for their antimicrobial properties, aiming to thoroughly present the state of the art on oral infection prevention in the ear, nose, and throat (ENT) field.

The in-vitro effects of white henna addition on the Candida albicans adhesion and physical properties of denture base resin

Purpose:

This in-vitro study evaluated and compared the effect of white henna (WH) and natural henna (NH) addition on Candida albicans adhesion and physical properties of the denture base material.

Materials and methods:

A total of 243 acrylic resin specimens (9 per group) were divided as follows: 81 for flexural strength, 81 for Candida albicans adherence test, and 81 for surface roughness, translucency, and hardness. Heat-polymerized acrylic resin specimens were prepared by adding 0.5, 1.0, 1.5, or 2.0 wt% of WH or NH. Candida albicans adhesion was determined using direct culture and slide count methods. Flexural strength, surface roughness, hardness, and translucency were measured using the three-point bending test, profilometer, Vickers hardness test, and spectrophotometer, respectively. ANOVA and post hoc Tukey’s tests were performed for data analysis.

Results:

Addition of 0.5% WH, 1% WH, and 0.5% NH to denture base resin significantly decreased Candida albicans adhesion (p<0.05). WH and NH significantly decreased the flexural strength and translucency, except 0.5% WH, and significantly increased surface roughness, except 0.5% WH and 0.5% NH. WH addition showed nonsignificant differences in the hardness, while NH addition significantly decreased hardness (p<0.05).

Conclusion:

Addition of WH and NH decreased C. albicans adhesion to PMMA denture base resin. However, flexural strength, translucency, and surface roughness were adversely affected, particularly at higher concentrations. Hardness was reduced with NH only.

Phytochemistry and Pharmacology of the Genus Equisetum (Equisetaceae): A Narrative Review of the Species with Therapeutic Potential for Kidney Diseases

The Equisetum genus, Equisetaceae family, is widely distributed worldwide and may be the oldest nonextinct genus on Earth. There are about 30 known species, which are very often used in traditional medicine with diverse applications. This review aimed to compile scientific reports about Equisetum species with relevant pharmacological properties and/or therapeutic potential for kidney diseases. Our bibliographic survey demonstrates that the most widespread traditional use of Equisetum is as a diuretic, followed by the treatment of genitourinary diseases (kidney diseases, urethritis, kidney stones, and others), inflammation, wound healing, rheumatic diseases, prostatitis, and hypertension. The most popular species from the Equisetum genus with medicinal use is E. arvense L., whose diuretic effect was confirmed in animal models and clinical trials. The species E. bogotense Kunth also demonstrated the beneficial effect of inducing diuresis in both experimental and clinical assays. Several other species have also been studied regarding their therapeutic potential, showing different biological actions. Regarding the chemical composition, it contains many active constituents, such as alkaloids, flavonoids, phenol, phytosterols, saponins, sterols, silicic acid, tannin, triterpenoids, and volatile oils. However, despite the widespread traditional use, many species need to be explored in detail for scientific validation of popular use. Indeed, the species of the Equisetum genus have great potential in the management of kidney disorders.

Antidiabetic effect of Equisetum giganteum L. extract on alloxan-diabetic rabbit

ETHNOPHARMACOLOGICAL RELEVANCE

Equisetum giganteum has been traditionally used as an anti-diabetic herbal remedy to treat diabetes in the southern state of Rio Grande do Sul in Brazil.

AIM OF THE STUDY

Considering the ethonopharmacology and historical importance of E. giganteum, its potential antidiabetic effect was evaluated in alloxan induced diabetic rabbits.

MATERIAL AND METHODS

Samples of Equisetum giganteum were collected in the city of Ouro Preto, Minas Gerais, Brazil. Butanolic and aqueous extracts were prepared and subsequently evaluated for anti-diabetic properties in vivo using albino male rabbits. At the end of the treatment period, the animals were euthanized, and histopathological analysis were carried out. The following biochemical parameters were studied: glucose, triacylglycerol, cholesterol, albumin, creatinine, glycosylated hemoglobin and lipase. The phytochemical profile of the extracts was studied by liquid chromatography techniques coupled to a UV/VIS detector and high-resolution mass spectrometry.

RESULTS

Both aqueous and butanolic extracts were capable of reducing significantly the levels of glucose, cholesterol and triacylglycerol and thus demonstrating their hypolipidemic and hypoglycemiant effects. Furthermore, the extracts prevented the occurrence of hepatic complications during treatment. The phytochemical profile of the extracts was investigated, and the natural products detected were in agreement with those that had been previously described in the literature.

CONCLUSION

Based on the significant reductions in biochemical parameters and the histologic evidence for the absence of complications in the liver, pancreas of the treated animals, Equisetum giganteum can be a therapeutically relevant resource in the treatment of diabetes and hyperlipidemia.

The impact of flavonoids-rich Ziziphus jujuba Mill. Extract on Staphylococcus aureus biofilm formation

Background

To evaluate the in vitro antibacterial effect of flavonoids-rich Ziziphus jujuba Mill. extract (FZM) against the formation of bacterial biofilms (BBFs) in Staphylococcus aureus.

Results

FZM can effectively inhibit the formation of S. aureus biofilms in vitro. Morphological observation showed a decrease in both biofilm adhesion and thickness. Results of confocal laser scanning microscopy used to detect the thickness of the BBFs showed that FZM treatment reduced the thickness of the BBFs. Furthermore, after the Image-Pro Plus v.6.0 analysis of the fluorescence intensity, FZM treatment reduced the thickness of the BBFs as well as the proportion of green fluorescence. Scanning electron microscopy showed that FZM can disrupt the channels available for substance exchange in the biofilm, thus exposing the bacterial cells and damaging its three-dimensional structures.

Conclusion

FZM can inhibit biofilm formation, improve the bacterial pH environment, and eliminate the hydrophobic effect of reactive oxygen species and flavonoids.

Comparative inhibitory effects of 4-allylpyrocatechol isolated from Piper betle on Streptococcus intermedius, Streptococcus mutans, and Candida albicans

Streptococcus intermedius, Streptococcus mutans, and Candida albicans are harmful oral pathogens and prone to resist chemical antimicrobial agents. Active ingredients from plants are of increasing interest as an alternative. This study aims to compare antimicrobial effects of 4-allylpyrocatechol (APC) extracted from Piper betle on these oral pathogens. Minimum concentration of APC against the tested pathogens was determined using a broth microdilution assay. Killing kinetic study of APC was carried out within 24 h. Morphology of the pathogenic cells was assessed using scanning electron microscopy (SEM). Anti-biofilm was investigated using crystal violet assay and confocal laser scanning microscopy (CLSM). The results showed that the mechanism of inhibition of APC was bactericidal and fungicidal effects. APC at minimum concentration of 400 μg/mL could completely kill Streptococcus and Candida spp., however, the killing rate on S. intermedius and C. albicans was significantly faster than on S. mutans. APC inhibited biofilm formation of C. albicans more efficiently than that of the bacterial cells. Cell morphology from SEM indicated that APC caused bacterial cell membrane destruction and inhibited fungal budding or tubing formation. CLSM images confirmed the killing potential of APC and suggested that bacterial dead cells could be easier washed out than the fungal dead cells. It is concluded that APC potentially inhibits growth and biofilms of oral Streptococcus and Candida spp. in different mechanism of action and killing rate. APC can be considered as a promising agent for preventing and treating dental disorders caused by S. intermedius, S. mutans, and C. albicans.

Anti-biofilm Action of Chenopodium ambrosioides Extract, Cytotoxic Potential and Effects on Acrylic Denture Surface

Considering the challenge to control Candida-associated denture stomatitis, the search for antifungal substances derived from natural sources has become a trend in the literature. In this study the following effects of Chenopodium ambrosioides extract (CAE) were investigated: action against biofilms of Candida albicans, its cytotoxic potential, and changes caused in acrylic resin. The CAE was characterized by High Performance Liquid Chromatography (HPLC). The susceptibility of C. albicans to CAE was investigated by Minimum Inhibitory Concentration and Minimum Fungicidal Concentration (MIC and MFC) tests. Acrylic resin disks were fabricated, and C. albicans biofilms were developed on these for 48 h. Afterward the disks were immersed for 10 min in: PBS (Negative Control); 1% Sodium Hypochlorite (1% SH, Positive Control) or CAE at MIC or 5xMIC. The biofilms were investigated relative to counts and metabolic activity. The cytotoxic potential in keratinocytes and fibroblasts was verified by MTT test. Change in color and roughness of the acrylic resin was analyzed after 28 days of immersion in CAE. The data were analyzed by the ANOVA considering a 5% level of significance. The main compounds detected by HPLC were kaempferol and quercetin. Both MIC and MFC obtained the value of 0.25 mg/mL. The MIC was sufficient to significantly reduce the counts and activity of the biofilm cells (p < 0.0001), while 5xMIC resulted in almost complete eradication, similar to 1% SH. Keratinocytes and fibroblasts exposed to the MIC and 5xMIC presented cell viability similar to that of the Control Group (p > 0.05). No important changes in acrylic resin color and roughness were detected, even after 28 days. It could be concluded that the immersion of acrylic resin in C. ambrosioides extract in its minimum inhibitory concentration was effective for the reduction of C. albicans biofilms without any evidence of cytotoxic effects or changes in roughness and color of this substrate.

Recent Advances in Non-Conventional Antimicrobial Approaches for Chronic Wound Biofilms: Have We Found the 'Chink in the Armor'?

Chronic wounds are a major healthcare burden, with huge public health and economic impact. Microbial infections are the single most important cause of chronic, non-healing wounds. Chronic wound infections typically form biofilms, which are notoriously recalcitrant to conventional antibiotics. This prompts the need for alternative or adjunct ‘anti-biofilm’ approaches, notably those that account for the unique chronic wound biofilm microenvironment. In this review, we discuss the recent advances in non-conventional antimicrobial approaches for chronic wound biofilms, looking beyond standard antibiotic therapies. These non-conventional strategies are discussed under three groups. The first group focuses on treatment approaches that directly kill or inhibit microbes in chronic wound biofilms, using mechanisms or delivery strategies distinct from antibiotics. The second group discusses antimicrobial approaches that modify the biological, chemical or biophysical parameters in the chronic wound microenvironment, which in turn enables the disruption and removal of biofilms. Finally, therapeutic approaches that affect both, biofilm bacteria and microenvironment factors, are discussed. Understanding the advantages and limitations of these recent approaches, their stage of development and role in biofilm management, could lead to new treatment paradigms for chronic wound infections. Towards this end, we discuss the possibility that non-conventional antimicrobial therapeutics and targets could expose the ‘chink in the armor’ of chronic wound biofilms, thereby providing much-needed alternative or adjunct strategies for wound infection management.

Equisetum arvense L. Extract Induces Antibacterial Activity and Modulates Oxidative Stress, Inflammation, and Apoptosis in Endothelial Vascular Cells Exposed to Hyperosmotic Stress

Background

The antimicrobial activity of the Equisetum arvense L. extract and the mechanisms involved in the in vitro effects on endothelial vascular cells exposed to hyperosmotic stress were evaluated.

Methods

Antimicrobial activity was evaluated by disk diffusion method and minimum inhibitory concentration (MIC) determination, and oxidative stress, inflammation, and apoptosis, in pretreatment with Equisetum arvense L., caffeic acid, and cathechin, were quantified.

Results

The results have shown that Equisetum arvense L. exhibited antibacterial effects only on pathogenic gram-positive cocci. The modulatory activity of Equisetum arvense L. on endothelial cells exposed to hypertonic medium was different and depended on the concentration used. Low concentrations of tested compounds exerted antioxidant effect and diminished the activity of caspase-8 and also increased IκB expression while in high doses, Equisetum arvense L. was prooxidant, induced apoptosis, and decreased IL-6 secretion.

Conclusions

These experimental findings suggest that Equisetum arvense L. has antibacterial effects on gram-positive cocci and, administered in low dose, may be a new therapeutic approach for diseases associated with hypertonic conditions or oxidative stress and apoptosis.

Extracts of Equisetum giganteum L and Copaifera reticulate Ducke show strong antiviral activity against the sexually transmitted pathogen herpes simplex virus type 2

ETHNOPHARMACOLOGICAL RELEVANCE

Equisetum giganteum L and Copaifera reticulate Ducke have been traditionally used by women of the Tacana tribe in the Bolivian Amazonas for genital hygiene and for treatment of genital infection/inflammation.

AIM OF THE STUDY

To assess the ability of extracts from Equisetum giganteum L and Copaifera reticulate Ducke to block genital viral infection by herpes simplex virus type 2.

MATERIALS AND METHODS

Equisetum giganteum L and Copaifera reticulate Ducke were collected from the Amazon region of La Paz, Bolivia. Extracts were prepared and screened for anti-viral activity against herpes simplex virus type 2 (HSV-2) using both in vitro and in in vivo models of infection.

RESULTS

Equisetum giganteum L and Copaifera reticulate Ducke efficiently blocked HSV-2 infection of cell cultures without major cell cytotoxic effects. Extracts of Equisetum giganteum L and Copaifera reticulate Ducke could prevent HSV-2 disease development when administered together with virus in a mouse model of genital HSV-2 infection. In vitro analyses revealed that both plant extracts exerted their anti-HSV-2 effects by interfering with viral cell attachment and entry, but could not block viral replication post entry.

CONCLUSIONS

These studies show that extracts of Equisetum giganteum L and Copaifera reticulate Ducke have potent antiviral activities against HSV-2 comparable to those two previously identified plants, Croton lechleri Müll. Arg. and Uncaria tomentosa (Willd. ex Schult.) DC. These studies confirm that plants used by the Tacana tribe could be explored further for the development of novel topical antiviral microbicides.

Antimicrobial activity of denture adhesive associated with Equisetum giganteum- and Punica granatum-enriched fractions against Candida albicans biofilms on acrylic resin surfaces

Candida biofilms adhere to the internal surface of removable dentures, which is an etiological factor in the pathogenesis of denture stomatitis (DS). Adhesive materials are used at the base of maxillary complete dentures to improve their retention and chewing qualities. This article reports the antimicrobial activity of the enriched fractions of Equisetum giganteum and Punica granatum incorporated into a denture adhesive against C. albicans biofilm. The biofilms were induced on the surface of heat-cured acrylic resin specimens that were previously treated with a mixture of adhesive/herb extracts. The antimicrobial activity was evaluated by CFU counts, XTT reduction, and SEM and CLSM analysis. Both herb extracts amplified the anti-biofilm action of the adhesive on the acrylic resin by up to 12 h. Therefore, when these extracts were combined with COREGA®, they played a collaborative and innovative role in biofilm control and can be considered alternatives for temporary use in the treatment and/or prevention of DS.

Equisetum giganteum influences the ability of Candida albicans in forming biofilms over the denture acrylic resin surface

CONTEXT

Equisetum giganteum L. (Equisetaceae) is an endemic plant of Central and South America used in traditional medicine. Natural drugs have been frequently used in the treatment of a myriad of diseases, proving to be an alternative to synthetic chemicals, and have been intensively studied in the prevention of sicknesses, including oral diseases.

OBJECTIVE

This study evaluated the in vitro antiadherent activity of E. giganteum extract against Candida albicans biofilms.

MATERIALS AND METHODS

Crystal violet and colony-forming units assays were used to quantify the total biofilm biomass and biofilm living cells on a denture base acrylic resin pretreated with hydroethanolic extract of E. giganteum in different concentrations (50, 25, 16, 8, and 4 mg/mL), after 24 h of biofilm development.

RESULTS

Equisetum giganteum affected biofilms by reduction of biomass and living cells per area of acrylic specimens. The results revealed reduction of 15-44% of the biofilm mass and reduction of numbers of colony-forming units (CFUs) present in biofilms (79%) compared to the untreated control (CTRL/PBS). At all concentrations, it demonstrated important antiadherent activity on Candida albicans biofilms, the main microbe in denture stomatitis.

DISCUSSION AND CONCLUSION

The present findings show that E. giganteum antimicrobial effects may qualify the extract as a promising natural alternative for topical treatment or prevention of denture stomatitis. The usage of drugs made of natural products shows advantages in relation to synthetic drugs on the market, such as lower cost, lower toxicity, and in relation to the occurrence of microbial resistance.

Contribution of the phenolic composition to the antioxidant, anti-inflammatory and antitumor potential of Equisetum giganteum L. and Tilia platyphyllos Scop

Naturally-occurring phytochemicals have received pivotal attention in the last few years, due to the increasing evidence of biological activities. Thus, in the present study, the antioxidant, anti-inflammatory and antitumor potentials of hydroethanolic extracts rich in phenolic compounds obtained from Equisetum giganteum L. and Tilia platyphyllos Scop. were assessed and directly correlated with their content of phenolic compounds, by using HPLC-DAD-ESI/MS analysis. T. platyphyllos showed the higher bioactive potential, evaluated in terms of antioxidant (radical scavenging effects - 105 μg mL^-1, reducing power - 123 μg mL^-1, β-carotene bleaching inhibition - 167 μg mL^-1, and lipid peroxidation inhibition - 56 μg mL^-1), anti-inflammatory (225 μg mL^-1 inhibited 50% of nitric oxide production) and antitumor (breast - 224 μg mL^-1; lung - 247 μg mL^-1; cervical - 195 μg mL^-1 and hepatocellular - 173 μg mL^-1 carcinoma cells) activity, without having cytotoxic effects (>400 μg mL^-1). These biological properties were positively correlated with its content and composition of phenolic compounds. Flavonoid contents were markedly higher than the content of phenolic acids, in both samples, being respectively 50.4 mg g^-1 and 11.65 mg g^-1 for T. platyphyllos, and 21.7 mg g^-1 and 4.98 mg g^-1 for E. giganteum. Moreover, while in E. giganteum extract, kaempferol-O-glucoside-O-rutinoside was the most abundant flavonoid, in T. platyphyllos extract protocatechuic acid and (-)-epicatechin were the most abundant phenolic acid and flavonoid, respectively. In relation to their content of phenolic acids, protocatechuic and caffeic acids existed in higher abundance in T. platyphyllos and E. giganteum hydroethanolic extracts, respectively. However, it would be interesting to evaluate the in vivo efficacy of both plant extracts to unveil the involved modes of action and to establish effective therapeutic doses.

Heat-Polymerized Resin Containing Dimethylaminododecyl Methacrylate Inhibits Candida albicans Biofilm

The prevalence of stomatitis, especially caused by Candida albicans, has highlighted the need of new antifungal denture materials. This study aimed to develop an antifungal heat-curing resin containing quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM), and evaluate its physical performance and antifungal properties. The discs were prepared by incorporating DMADDM into the polymer liquid of a methyl methacrylate-based, heat-polymerizing resin at 0% (control), 5%, 10%, and 20% (w/w). Flexure strength, bond quality, surface charge density, and surface roughness were measured to evaluate the physical properties of resin. The specimens were incubated with C. albicans solution in medium to form biofilms. Then Colony-Forming Units, XTT assay, and scanning electron microscope were used to evaluate antifungal effect of DMADDM-modified resin. DMADDM modified acrylic resin had no effect on the flexural strength, bond quality, and surface roughness, but it increased the surface charge density significantly. Meanwhile, this new resin inhibited the C. albicans biofilm significantly according to the XTT assay and CFU counting. The hyphae in C. albicans biofilm also reduced in DMADDM-containing groups observed by SEM. DMADDM modified acrylic resin was effective in the inhibition of C. albicans biofilm with good physical properties.