Effects of Acetone Fraction From Buchenavia tomentosa Aqueous Extract and Gallic Acid on Candida albicans Biofilms and Virulence Factors

Innovative antifungal Therapy: In vivo evaluation of 3-Ethyl-6,7-Dihydroxy-2-Phenyl-Chromen-4-One purified from Alpinia officinarum on Cryptococcus neoformans

Cryptococcus neoformans infections pose a significant challenge to human health, particularly due to the lack of effective drugs and the severe side effects of those currently available. This study aimed to evaluate the efficacy of a purified compound, 3-ethyl-6,7-dihydroxy-2-phenyl-chromen-4-one (EDPC), extracted from Alpinia officinarum, in comparison to fluconazole, in treating rat models infected with C. neoformans. A total of 120 rats were divided into six groups: a negative control group, a group infected with 1 × 104 CFU/mL of C. neoformans (positive control), and four treatment groups receiving either 10 mg/kg, 20 mg/kg, or 30 mg/kg of EDPC, or 10 mg/kg of fluconazole. Colony-forming units (CFU) in the lungs were measured at 7, 14, 21, 28, 35, 42, and 49 days post-infection. The results showed that treatment with EDPC, at all doses, as well as fluconazole, significantly increased survival rates and reduced lung CFU counts in infected rats. Histological analysis revealed notable improvements in lung tissue across the treated groups. Additionally, levels of pro-inflammatory cytokines TNF-α, IL-1β, and IL-17 were markedly reduced in animals treated with EDPC compared to the untreated infected group. Antioxidant activity was observed, with increased glutathione (GSH) levels and decreased malondialdehyde (MDA) levels in treated rats. Moreover, EDPC treatments helped normalize biomarkers related to liver and kidney function, while fluconazole was associated with a significant increase in renal biomarkers, indicating potential kidney toxicity. In contrast, EDPC demonstrated a safer profile regarding kidney function, making it a promising therapeutic agent for C. neoformans infections for long-term use.

n -butanol fraction of Terminalia catappa possesses anti-Candida albicans properties and in vivo action on Tenebrio molitor alternative infection model

Current treatment of Candida infections is threatened by antifungal drug resistance. Thus, medicinal plants have been studied to identify new and highly effective antifungal substances with low toxicity. Here, we showed that the tannin-rich n-butanol fraction of Terminalia catappa (FBuOH) possesses antifungal and antibiofilm properties and protects Tenebrio molitor larvae against Candida albicans infection. FBuOH showed antifungal activity against Candida spp. vaginal isolates (MIC values ranged from 7 to 500 μg/mL). Moreover, a combination of FBuOH with fluconazole (FICI ≤0.5) showed considerably increased anti-yeast, anti-biofilm activity and significantly improved the survival rate (up to 100 %) of T. molitor larvae against C. albicans infection. Furthermore, FBuOH acted synergistically with fluconazole by reducing C. albicans membrane ergosterol content. These results could also explain the synergistic activity between FBuOH and fluconazole, indicating that FBuOH exerted its effects on C. albicans membrane integrity, increasing its permeability. Our findings provide insights into the antifungal activity and low cytotoxicity of FBuOH, showing its potential use as a new antimycotic.

Barbosa E, Rocha HAO, Chaves GM. Mechanism of action and synergistic effect of Eugenia uniflora extract in Candida spp

The limited arsenal of antifungal drugs have prompted the search for novel molecules with biological activity. This study aimed to characterize the antifungal mechanism of action of Eugenia uniflora extract and its synergistic activity with commercially available antifungal drugs on the following Candida species: C. albicans, C. tropicalis, C. glabrata, C. parapsilosis and C. dubliniensis. In silico analysis was performed to predict antifungal activity of the major compounds present in the extract. Minimal inhibitory concentrations (MICs) were determined in the presence of exogenous ergosterol and sorbitol. Yeast cells were grown in the presence of stressors. The loss of membrane integrity was assessed using propidium iodide staining (fluorescence emission). Synergism between the extract and antifungal compounds (in addition to time kill-curves) was determined. Molecular docking revealed possible interactions between myricitrin and acid gallic and enzymes involved in ergosterol and cell wall biosynthesis. Candida cells grown in the presence of the extract with addition of exogenous ergosterol and sorbitol showed 2 to 8-fold increased MICs. Strains treated with the extract revealed greater loss of membrane integrity when compared to their Fluconazole counterparts, but this effect was less pronounced than the membrane damage caused by Amphotericin B. The extract also made the strains more susceptible to Congo red and Calcofluor white. A synergistic action of the extract with Fluconazole and Micafungin was observed. The E. uniflora extract may be a viable option for the treatment of Candida infections.

Evaluation of antibacterial, antifungal and antibiofilm activities of A. baumannii-derived tannase and gallic acid against uropathogenic microorganisms

One of the most prevalent infectious diseases and a key driver of antibiotic prescriptions in pediatrics is urinary tract infection (UTI). Due to the emergence of more resistant uropathogenic bacterial and fungal strains, current treatments are no longer effective, necessitating the urgent development of novel antibacterial and antifungal drugs. In this study, the antifungal, antibacterial, and anti-biofilm capabilities of compounds, such as tannase (TN) and gallic acid (GA), which were produced from a novel natural source, Acinetobacter baumannii (AB11) bacteria, were assessed for the inactivation of uropathogenic microorganisms (UMs). Ammonium sulphate precipitation, ion exchange, high-performance liquid chromatography, and gel filtration were used to purify TN and GA that were isolated from A. baumannii. A 43.08 % pure TN with 1221.2 U/mg specific activity and 10.51 mg/mL GA was obtained. The antibacterial, antifungal and anti-biofilm activities of TN and GA were evaluated against UMs and compared to those of commercially available antibiotics including sulfamethoxazole (SXT), levofloxacin (LEV), ciprofloxacin (CIP), amikacin (Ak), and nitrofurantoin (F). The results showed that TN and GA were superior to commercial antibiotics in their ability to inactivate UMs and considerably reduced biofilms formation. Additionally, the GA emerges as the top substitute for currently available medications, demonstrating superior antibacterial and antibiofilm properties against all UMs evaluated in this study. The results of this investigation showed that A. baumannii-derived TN and GA could be utilized as an alternative medication to treat UTIs.

Candida die-off: Adverse effect and neutralization with phytotherapy approaches

Candida albicans is the main species that causes 3rd most common bloodstream infection candidiasis in hospitalization. Once it has been diagnosed and treated with antifungal medications accurately, large amounts of Candida cells are killed off rapidly known as Candida die-off or Jarisch-Herxheimer reactions. When Candida cells are killed off quickly, a large no. of toxic substances are released simultaneously. This flood of endotoxins is noxious (harmful) and causes the kidneys and liver to work overtime to try and remove them which causes worsening of symptoms in patients. As a complementary and holistic approach to addressing Candida die-off and its associated symptoms, plant-based remedies i.e., phytotherapy have been gaining increased attention. In this review paper, we have discussed major factors involved in provoking Candida die-off, their management by phytotherapy, challenges associated with the toxic effects due to die-off, and neutralization of Candida die-off through phytotherapy to manage this problem and challenges. In conclusion, this article serves as a meticulous compilation of knowledge on the intriguing subject of Candida die-off, presenting a distinct and informative perspective that has the potential to pave the way for new insights in the realm of plant-based antifungal therapeutics.

Cyclic strain of poly (methyl methacrylate) surfaces triggered the pathogenicity of Candida albicans

Candida albicans is an opportunistic yeast and the primary etiological factor in oral candidiasis and denture stomatitis. The pathogenesis of C. albicans could be triggered by several variables, including environmental, nutritional, and biomaterial surface cues. Specifically, biomaterial interactions are driven by different surface properties, including wettability, stiffness, and roughness. Dental biomaterials experience repetitive (cyclic) stresses from chewing and biomechanical movements. Pathogenic biofilms are formed over these biomaterial surfaces under cyclic strain. This study investigated the effect of the cyclic strain (deformation) of biomaterial surfaces on the virulence of Candida albicans. Candida biofilms were grown over Poly (methyl methacrylate) (PMMA) surfaces subjected to static (no strain) and cyclic strain with different levels (ε˜x=0.1 and 0.2%). To evaluate the biomaterial-biofilm interactions, the biofilm characteristics, yeast-to-hyphae transition, and the expression of virulent genes were measured. Results showed the biofilm biomass and metabolic activity to be significantly higher when Candida adhered to surfaces subjected to cyclic strain compared to static surfaces. Examination of the yeast-to-hyphae transition showed pseudo-hyphae cells (pathogenic) in cyclically strained biomaterial surfaces, whereas static surfaces showed spherical yeast cells (commensal). RNA sequencing was used to determine and compare the transcriptome profiles of cyclically strained and static surfaces. Genes and transcription factors associated with cell adhesion (CSH1, PGA10, and RBT5), biofilm formation (EFG1), and secretion of extracellular matrix (ECM) (CRH1, ADH5, GCA1, and GCA2) were significantly upregulated in the cyclically strained biomaterial surfaces compared to static ones. Genes and transcription factors associated with virulence (UME6 and HGC1) and the secretion of extracellular enzymes (LIP, PLB, and SAP families) were also significantly upregulated in the cyclically strained biomaterial surfaces compared to static. For the first time, this study reveals a biomaterial surface factor triggering the pathogenesis of Candida albicans, which is essential for understanding, controlling, and preventing oral infections. STATEMENT OF SIGNIFICANCE: Fungal infections produced by Candida albicans are a significant contributor to various health conditions. Candida becomes pathogenic when certain environmental conditions change, including temperature, pH, nutrients, and CO2 levels. In addition, surface properties, including wettability, stiffness, and roughness, drive the interactions between Candida and biomaterials. Clinically, Candida adheres to biomaterials that are under repetitive deformation due to body movements. In this work, we revealed that when Candida adhered to biomaterial surfaces subjected to repetitive deformation, the microorganism becomes pathogenic by increasing the formation of biofilms and the expression of virulent factors related to hyphae formation and secretion of enzymes. Findings from this work could aid the development of new strategies for treating fungal infections in medical devices or implanted biomaterials.

The potential role of plant secondary metabolites on antifungal and immunomodulatory effect

With the widespread use of antibiotic drugs worldwide and the global increase in the number of immunodeficient patients, fungal infections have become a serious threat to global public health security. Moreover, the evolution of fungal resistance to existing antifungal drugs is on the rise. To address these issues, the development of new antifungal drugs or fungal inhibitors needs to be targeted urgently. Plant secondary metabolites are characterized by a wide variety of chemical structures, low price, high availability, high antimicrobial activity, and few side effects. Therefore, plant secondary metabolites may be important resources for the identification and development of novel antifungal drugs. However, there are few studies to summarize those contents. In this review, the antifungal modes of action of plant secondary metabolites toward different types of fungi and fungal infections are covered, as well as highlighting immunomodulatory effects on the human body. This review of the literature should lay the foundation for research into new antifungal drugs and the discovery of new targets. KEY POINTS: • Immunocompromised patients who are infected the drug-resistant fungi are increasing. • Plant secondary metabolites toward various fungal targets are covered. • Plant secondary metabolites with immunomodulatory effect are verified in vivo.

Alkyl Gallates as Potential Antibiofilm Agents: A Review

Biofilms, which consist of microorganisms embedded in a polymer-rich matrix, contribute to a variety of infections and increase antimicrobial resistance. Thus, there is a constant need to develop new chemotherapeutic agents to combat biofilms. This review article focuses on the use of alkyl gallates, gallic acid and its esters (methyl, ethyl, propyl, butyl, hexyl, octyl, and dodecyl gallate), most of which are found in plants, to inhibit biofilm formation. The studies under review reveal that alkyl gallates have the capacity to prevent biofilm development and eradicate mature biofilms through mechanisms that suppress the synthesis of the extracellular polymeric matrix, inhibit quorum-sensing signaling, and alter the microbial cell membrane. The effects are stronger the greater the length of the alkyl chain. Moreover, the alkyl gallates' preventive activity against biofilm formation occurs at doses below the minimum inhibitory concentration. More importantly, combining alkyl gallates with antimicrobials or blue-light irradiation produces a synergistic effect on the inhibition of biofilm formation that can be used to treat infections and overcome microbial resistance.

Streptomyces: Derived Active Extract Inhibits Candida albicans Biofilm Formation

Candida albicans is an opportunistic pathogen that causes biofilm-associated infections. C. albicans biofilms are known to display reduced susceptibility to antimicrobials and high rates of acquired antibiotic resistance, and biofilm forming in C. albicans further hampers treatment options and highlights the need for new antibiofilm strategies. Identifying active components from desert actinomycetes strains to inhibit the formation of C. albicans biofilms represents an effective treatment strategy. In this study, actinomycetes that can inhibit C. albicans biofilm formation were isolated from the Taklimakan Desert, and the underlying mechanisms were explored. After screening the anti-C.albicans biofilm activities of culture supernatants from 170 Actinomycete strains, six strains showed significant inhibition of C. albicans biofilm formation. Microscopic examination showed a reduction in biofilm formation of C. albicans treated with supernatants from actinomycetes. Scanning electron microscopy showed that the morphological changes in biofilm cells were caused by cell membrane rupture and cell material leakage. Then, C.albicans biofilms were destroyed by changing the content of extracellular polysaccharides or degrading extracellular DNA. Finally, a preliminary study on active substances extracted from a new species (TRM43335) showed that the substances that inhibited the formation of biofilms might be peptides. This study provides preliminary evidence that desert actinomyces strains have inhibitory effects on the biofilm development of C. albicans.

Demonstration of Allium sativum Extract Inhibitory Effect on Biodeteriogenic Microbial Strain Growth, Biofilm Development, and Enzymatic and Organic Acid Production

To the best of our knowledge, this is the first study demonstrating the efficiency of Allium sativum hydro-alcoholic extract (ASE) againstFigure growth, biofilm development, and soluble factor production of more than 200 biodeteriogenic microbial strains isolated from cultural heritage objects and buildings. The plant extract composition and antioxidant activities were determined spectrophotometrically and by HPLC-MS. The bioevaluation consisted of the qualitative (adapted diffusion method) and the quantitative evaluation of the inhibitory effect on planktonic growth (microdilution method), biofilm formation (violet crystal microtiter method), and production of microbial enzymes and organic acids. The garlic extract efficiency was correlated with microbial strain taxonomy and isolation source (the fungal strains isolated from paintings and paper and bacteria from wood, paper, and textiles were the most susceptible). The garlic extract contained thiosulfinate (307.66 ± 0.043 µM/g), flavonoids (64.33 ± 7.69 µg QE/g), and polyphenols (0.95 ± 0.011 mg GAE/g) as major compounds and demonstrated the highest efficiency against the Aspergillus versicolor (MIC 3.12-6.25 mg/mL), A. ochraceus (MIC: 3.12 mg/mL), Penicillium expansum (MIC 6.25-12.5 mg/mL), and A. niger (MIC 3.12-50 mg/mL) strains. The extract inhibited the adherence capacity (IIBG% 95.08-44.62%) and the production of cellulase, organic acids, and esterase. This eco-friendly solution shows promising potential for the conservation and safeguarding of tangible cultural heritage, successfully combating the biodeteriogenic microorganisms without undesirable side effects for the natural ecosystems.

Plant Preparations and Compounds with Activities against Biofilms Formed by Candida spp

Fungi from the genus Candida are very important human and animal pathogens. Many strains can produce biofilms, which inhibit the activity of antifungal drugs and increase the tolerance or resistance to them as well. Clinically, this process leads to persistent infections and increased mortality. Today, many Candida species are resistant to drugs, including C. auris, which is a multiresistant pathogen. Natural compounds may potentially be used to combat multiresistant and biofilm-forming strains. The aim of this review was to present plant-derived preparations and compounds that inhibit Candida biofilm formation by at least 50%. A total of 29 essential oils and 16 plant extracts demonstrate activity against Candida biofilms, with the following families predominating: Lamiaceae, Myrtaceae, Asteraceae, Fabaceae, and Apiacae. Lavandula dentata (0.045–0.07 mg/L), Satureja macrosiphon (0.06–8 mg/L), and Ziziphora tenuior (2.5 mg/L) have the best antifungal activity. High efficacy has also been observed with Artemisia judaica, Lawsonia inermis, and Thymus vulgaris. Moreover, 69 plant compounds demonstrate activity against Candida biofilms. Activity in concentrations below 16 mg/L was observed with phenolic compounds (thymol, pterostilbene, and eugenol), sesquiterpene derivatives (warburganal, polygodial, and ivalin), chalconoid (lichochalcone A), steroidal saponin (dioscin), flavonoid (baicalein), alkaloids (waltheriones), macrocyclic bisbibenzyl (riccardin D), and cannabinoid (cannabidiol). The above compounds act on biofilm formation and/or mature biofilms. In summary, plant preparations and compounds exhibit anti-biofilm activity against Candida. Given this, they may be a promising alternative to antifungal drugs.

3,4,5-Trihydroxybenzoic Acid Attenuates Ligature-Induced Periodontal Disease in Wistar Rats

BACKGROUND

3,4,5-Trihydroxybenzoic acid, which is also known as gallic acid, is an antiinflammatory agent that could provide beneficial effects in preventing periodontal inflammation. The present study aimed to evaluate the anti-inflammatory effects of gallic acid on experimental periodontitis in Wistar rats. Alveolar bone loss, osteoclastic activity, osteoblastic activity, and collagenase activity were also determined.

METHODS

Thirty-two Wistar rats were used in the present study. Study groups were created as following: Healthy control (C,n=8) group; periodontitis (P,n=8) group; periodontitis and 30 mg/kg gallic acid administered group (G30,n=8); periodontitis and 60 mg/kg gallic acid administered group (G60,n=8). Experimental periodontitis was created by placing 4-0 silk sutures around the mandibular right first molar tooth. Morphological changes in alveolar bone were determined by stereomicroscopic evaluation. Mandibles were undergone histological evaluation. Matrix metalloproteinase (MMP)-8, tissue inhibitor of MMPs (TIMP)-1, bone morphogenetic protein (BMP)-2 expressions, tartrateresistant acid phosphatase (TRAP) positive osteoclast cells, osteoblast, and inflammatory cell counts were determined.

RESULTS

The highest alveolar bone loss was observed in the periodontitis group. Both doses of gallic acid decreased alveolar bone loss as compared to the P group. TRAP-positive osteoclast cell counts were higher in the P group, and gallic acid successfully lowered these counts. Osteoblast cells also increased in gallic acid administered groups. Inflammation in the P group was also higher than those of C, G30, and G60 groups supporting the role of gallic acid in preventing inflammation. 30 and 60 mg/kg doses of gallic acid decreased MMP-8 levels and increased TIMP-1 levels. BMP levels increased in gallic acid administered groups, similar to several osteoblasts.

CONCLUSION

Present results revealed an anti-inflammatory effect of gallic acid, which was indicated by decreased alveolar bone loss and collagenase activity and increased osteoblastic activity.

Evaluation of Anti-Biofilm Capability of Cordycepin Against Candida albicans

INTRODUCTION

The opportunistic pathogen Candida albicans can form biofilms, resulting in drug resistance with great risk to medical treatment.

METHODOLOGY

We investigated the ability of C. albicans to form biofilms on different materials, as well as the inhibitory and eradicating effects of cordycepin on biofilm. The action mechanism of cordycepin against biofilm was studied by crystal violet staining, XTT [2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction method, phenol-sulfuric acid method, cellular superficial hydrophobicity (CSH) assay, and confocal laser scanning microscope observation. We also evaluated the acute toxicity of cordycepin in vivo.

RESULTS

The results showed facile formation of biofilms by C. albicans on polypropylene. The 50% minimum inhibitory concentration (MIC50) of cordycepin was 0.062 mg/mL. A concentration of 0.125 mg/mL significantly decreased biofilm formation, metabolic activity, secretion of extracellular polysaccharides, and relative CSH. Cordycepin could inhibit biofilm formation at low concentration without affecting fungal growth. In addition, cordycepin effectively eradicated 59.14% of mature biofilms of C. albicans at a concentration of 0.5 mg/mL. For acute toxicity, the LD50 (50% of lethal dose) of cordycepin was determined as higher than 500 mg/kg for mice.

CONCLUSION

The results of this study show that cordycepin significantly inhibited and eradicated biofilms by decreasing metabolic activity, the ratio of living cells, the hydrophobicity, and damaging the extracellular polysaccharides of biofilm. These findings should facilitate more effective application of cordycepin and suggest a new direction for the treatment of fungal infections.

Epigallocatechin gallate and gallic acid affect colonization of abiotic surfaces by oral bacteria

OBJECTIVES

epigallocatechin gallate and gallic acid are known antimicrobial agents. Their roles in controlling microbial colonization, such as bacterial attachment and biofilm formation, are however not completely clear. This study aims to investigate their effects on the colonization of abiotic surfaces by oral bacteria and study the mechanism of their activities.

DESIGN

the effects of epigallocatechin gallate and gallic acid on cell surface physicochemical properties (hydrophobicity and charge) of a range of oral bacteria and their auto-aggregation, attachment and biofilm formation on different abiotic surfaces (glass, stainless steel and hydroxyapatite) were studied.

RESULTS

results show that epigallocatechin gallate inhibited bacterial attachment to the hard surfaces (except hydroxyapatite) by 0.2-1.4 log CFU cm^-2 by affecting cell surface hydrophobicity and charge. In addition, epigallocatechin gallate induced notches on cell surfaces of Streptococcus mutans without affecting their viability and biofilm formation. Gallic acid enhanced auto-aggregation (by 7.9-30.6 %) and biofilm formation by Actinomyces naeslundii (by 0.9-1.2 log CFU cm^-2) by causing calcium efflux from the cells.

CONCLUSIONS

the tested phytochemicals influenced the colonization of abiotic surfaces by oral bacteria through different mechanisms, most notably via affecting cell surface physicochemical properties, inducing changes in the shape of cell envelopes and causing calcium efflux.

Role of Antioxidant Molecules and Polymers in Prevention of Bacterial Growth and Biofilm Formation

Background:

Antioxidants are multifaceted molecules playing a crucial role in several cellular functions. There is by now a well-established knowledge about their involvement in numerous processes associated with aging, including vascular damage, neurodegenerative diseases and cancer. An emerging area of application has been lately identified for these compounds in relation to the recent findings indicating their ability to affect biofilm formation by some microbial pathogens, including Staphylococcus aureus, Streptococcus mutans, and Pseudomonas aeruginosa.

Methods:

A structured search of bibliographic databases for peer-reviewed research literature was performed using a focused review question. The quality of retrieved papers was appraised using standard tools.

Results:

One hundred sixty-five papers extracted from pubmed database and published in the last fifteen years were included in this review focused on the assessment of the antimicrobial and antibiofilm activity of antioxidant compounds, including vitamins, flavonoids, non-flavonoid polyphenols, and antioxidant polymers. Mechanisms of action of some important antioxidant compounds, especially for vitamin C and phenolic acids, were identified.

Conclusion:

The findings of this review confirm the potential benefits of the use of natural antioxidants as antimicrobial/antibiofilm compounds. Generally, gram-positive bacteria were found to be more sensitive to antioxidants than gram-negatives. Antioxidant polymeric systems have also been developed mainly derived from functionalization of polysaccharides with antioxidant molecules. The application of such systems in clinics may permit to overcome some issues related to the systemic delivery of antioxidants, such as poor absorption, loss of bioactivity, and limited half-life. However, investigations focused on the study of antibiofilm activity of antioxidant polymers are still very limited in number and therefore they are strongly encouraged in order to lay the foundations for application of antioxidant polymers in treatment of biofilm-based infections.

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.

Products Derived from Buchenavia tetraphylla Leaves Have In Vitro Antioxidant Activity and Protect Tenebrio molitor Larvae against Escherichia coli-Induced Injury

The relevance of oxidative stress in the pathogenesis of several diseases (including inflammatory disorders) has traditionally led to the search for new sources of antioxidant compounds. In this work, we report the selection of fractions with high antioxidant action from B. tetraphylla (BT) leaf extracts. In vitro methods (DPPH and ABTS assays; determination of phenolic and flavonoid contents) were used to select products derived from B. tetraphylla with high antioxidant action. Then, the samples with the highest potentials were evaluated in a model of injury based on the inoculation of a lethal dose of heat-inactivated Escherichia coli in Tenebrio molitor larvae. Due to its higher antioxidant properties, the methanolic extract (BTME) was chosen to be fractionated using Sephadex LH-20 column-based chromatography. Two fractions from BTME (BTFC and BTFD) were the most active fractions. Pre-treatment with these fractions protected larvae of T. molitor from the stress induced by inoculation of heat-inactivated E. coli. Similarly, BTFC and BTFD increased the lifespan of larvae infected with a lethal dose of enteroaggregative E. coli 042. NMR data indicated the presence of aliphatic compounds (terpenes, fatty acids, carbohydrates) and aromatic compounds (phenolic compounds). These findings suggested that products derived from B. tetraphylla leaves are promising candidates for the development of antioxidant and anti-infective agents able to treat oxidative-related dysfunctions.

Antifungal and Antivirulence Activities of Hydroalcoholic Extract and Fractions of Platonia insignis Leaves against Vaginal Isolates of Candida Species

Vulvovaginal candidiasis is a common fungal infection in women. In this study, Platonia insignis hydroalcoholic extract (PiHE) and its fractions were evaluated for antifungal and antivirulence activities against vaginal Candida species. Dichloromethane (DCMF) and ethyl acetate fractions (EAF) obtained from PiHE effectively inhibited the pathogen. Electrospray ionization mass spectrometry was used for identifying the main compounds in extracts. Minimal inhibitory and fungicidal concentrations (MIC and MFC, respectively) were determined by a broth microdilution assay. Furthermore, we evaluated the effect of the extract and fractions on the virulence properties of Candida albicans, and their cytotoxicity effect was determined on RAW 264.7 cells. Compounds found in extracts were flavonoid glycosides, mainly derivatives of quercetin and myricetin. Extracts showed antifungal potential, with the lowest MIC value for EAF (1.3 mg/mL) and inhibited Candida adherence and biofilm formation. EAF disrupted 48 h biofilms with an inhibition rate of more than 90%. The extract and its fractions exhibited no cytotoxicity. The antifungal effects were attributed to the ability of these extracts to alter the mitochondrial membrane potential for the release of pro-apoptotic factors in the cytosol. In conclusion, our data suggest that PiHE and EAF could act as novel candidates for the development of new therapeutic treatments against fungal infections.

Anti-Fungal Efficacy and Mechanisms of Flavonoids

The prevalence of fungal infections is growing at an alarming pace and the pathogenesis is still not clearly understood. Recurrence of these fungal diseases is often due to their evolutionary avoidance of antifungal resistance. The development of suitable novel antimicrobial agents for fungal diseases continues to be a major problem in the current clinical field. Hence, it is urgently necessary to develop surrogate agents that are more effective than conventional available drugs. Among the remarkable innovations from earlier investigations on natural-drugs, flavonoids are a group of plant-derived substances capable of promoting many valuable effects on humans. The identification of flavonoids with possible antifungal effects at small concentrations or in synergistic combinations could help to overcome this problem. A combination of flavonoids with available drugs is an excellent approach to reduce the side effects and toxicity. This review focuses on various naturally occurring flavonoids and their antifungal activities, modes of action, and synergetic use in combination with conventional drugs.

In Vitro and In Vivo Anti-Candida spp. Activity of Plant-Derived Products

Candidiasis therapy, especially for candidiasis caused by Candida non-albicans species, is limited by the relatively reduced number of antifungal drugs and the emergence of antifungal tolerance. This study evaluates the anticandidal activity of 41 plant-derived products against Candida species, in both planktonic and biofilm cells. This study also evaluates the toxicity and the therapeutic action of the most active compounds by using the Caenorhabditis elegans–Candida model. The planktonic cells were cultured with various concentrations of the tested agents. The Cupressus sempervirens, Citrus limon, and Litsea cubeba essential oils as well as gallic acid were the most active anticandidal compounds. Candida cell re-growth after treatment with these agents for 48 h demonstrated that the L. cubeba essential oil and gallic acid displayed fungistatic activity, whereas the C. limon and C. sempervirens essential oils exhibited fungicidal activity. The C. sempervirens essential oil was not toxic and increased the survival of C. elegans worms infected with C. glabrata or C. orthopsilosis. All the plant-derived products assayed at 250 µg/mL affected C. krusei biofilms. The tested plant-derived products proved to be potential therapeutic agents against Candida, especially Candida non-albicans species, and should be considered when developing new anticandidal agents.

Qingpeng Ointment Ameliorates Inflammatory Responses and Dysregulation of Itch-Related Molecules for Its Antipruritic Effects in Experimental Allergic Contact Dermatitis

The pathogenesis of itchy skin diseases including allergic contact dermatitis (ACD) is complicated and the treatment of chronic itch is a worldwide problem. One traditional Tibetan medicine, Qingpeng ointment (QP), has been used in treatment of ACD in China for years. In this study we used HPLC and LC/MS analysis, combined with a BATMAN-TCM platform, for detailed HPLC fingerprint analysis and network pharmacology of QP, and investigated the anti-inflammatory and antipruritic activities of QP on ACD induced by squaric acid dibutylester (SADBE) in mice. The BATMAN-TCM analysis provided information of effector molecules of the main ingredients of QP, and possible chronic dermatitis-associated molecules and cell signaling pathways by QP. In ACD mice, QP treatment suppressed the scratching behavior induced by SADBE in a dose-dependent manner and inhibited the production of Th1/2 cytokines in serum and spleen. Also, QP treatment reversed the upregulation of mRNAs levels of itch-related genes in the skin (TRPV4, TSLP, GRP, and MrgprA3) and DRGs (TRPV1, TRPA1, GRP, and MrgprA3). Furthermore, QP suppressed the phosphorylation of Erk and p38 in the skin. In all, our work indicated that QP can significantly attenuate the pathological alterations of Th1/2 cytokines and itch-related mediators, and inhibit the phosphorylation of MAPKs to treat the chronic itch.

Anadenanthera Colubrina vell Brenan: anti-Candida and antibiofilm activities, toxicity and therapeutical action

We evaluated the antifungal and antibiofilm potential of the hydroalcoholic extract of bark from Anadenanthera colubrina (vell.) Brenan, known as Angico, against Candida spp. Antifungal activity was evaluated using the microdilution technique through the Minimum Inhibitory and Fungicide Concentrations (MIC and MFC). The antibiofilm potential was tested in mature biofilms formed by Candida species and analyzed through the counting of CFU/mL and scanning electron micrograph (SEM). In vivo toxicity and therapeutic action was evaluated in the Galleria mellonella model. The treatment with the extract, in low doses, was able to reduce the growth of planktonic cells of Candida species. MIC values range between 19.5 and 39 µg/mL and MFC values range between 79 and 625 µg/mL. In addition was able to reduce the number of CFU/mL in biofilms and to cause structural alteration and cellular destruction, observed via SEM. A. colubrina showed low toxicity in the in vivo assay, having not affected the viability of the larvae at doses below 100mg/kg and high potential in the treatment of C. albicans infection. Considering its high antifungal potential, its low toxicity and potential to treatment of infections in in vivo model, A. colubrina extract is a strong candidate for development of a new agent for the treatment of oral candidiasis.

Silver nanoparticles coated with dodecanethiol used as fillers in non-cytotoxic and antifungal PBAT surface based on nanocomposites

In the present study, we report the preparation of antifungal and non-cytotoxic polymer nanocomposites with potential application in biomedical materials. Dodecanethiol-protected silver nanoparticles (AgNPs-DDT) were synthesized by a reduction/precipitation method and dispersed in chloroform to obtain stable colloidal dispersions. PBAT-based nanocomposites containing 0.25, 0.5 and 2 wt% AgNPs-DDT were prepared by casting method. The incorporation of AgNPs-DDT in PBAT matrix resulted in nanocomposites which combine improved mechanical performance and antifungal properties with a non-cytotoxic characteristic.