Lycopene induces apoptosis in Candida albicans through reactive oxygen species production and mitochondrial dysfunction

Cold atmospheric plasma fumigation suppresses postharvest apple Botrytis cinerea by triggering intracellular reactive oxygen species and mitochondrial calcium

Infection by Botrytis cinerea poses a great threat to the postharvest life of apple fruit. In this study, the effects of cold atmospheric plasma (CAP) fumigation on apple B. cinerea under different exposure times and intensities were investigated. The growth of B. cinerea in vitro and in vivo was significantly suppressed by the CAP fumigation at least 700 μL/L for 5 min. To reveal the possible mechanism of antifungal activity of CAP fumigation, the pathogen was exposed to 700 μL/L and 1000 μL/L for 5 min, respectively. The results indicated that the CAP-treated spores of the pathogen underwent shrinkage, cell membrane collapse and cytoplasmic vacuolation. The results obtained from the fluorescent probe assay and flow cytometry indicated that CAP caused the accumulation of reactive oxygen species (ROS), the elevation of mitochondrial and intracellular Ca2+ levels, and the decrease in mitochondrial membrane potential of the pathogen. Investigation on statues of cell life showed that typical hallmarks of apoptosis in the CAP-treated B. cinerea spores occurred, as indicted by a large degree of increased phosphatidylserine externalization, dysfunction of membrane permeability, DNA fragmentation, distortion of morphology, chromatin condensation, and metacaspase activation observed in B. cinerea spores after CAP fumigation. Overall, CAP fumigation triggered a metacaspase-dependent apoptosis of B. cinerea spores mediated by intracellular ROS burst and Ca2+ elevation via mitochondrial dysfunction and disruption, and therefore reduced the pathogenicity of B. cinerea and suppressed postharvest Botrytis rot of apple fruit. These results would provide an insight into the underlying mechanism of CAP fumigation acting on the pathogen. The CAP fumigation makes much convenient application of CAP in storage environment to deactivate microorganism.

Ethyl Isothiocyanate as a Novel Antifungal Agent Against Candida albicans

In the recent years, occurrence of candidiasis has increased drastically which leads to significant mortality and morbidity mainly in immune compromised patients. Glucosinolate (GLS) derivatives are reported to have antifungal activities. Ethyl isothiocyanate (EITC) and its antifungal activity and mechanism of action is still unclear against Candida albicans. The present work was designed to get a mechanistic insight in to the anti-Candida efficacy of EITC through in vitro and in vivo studies. EITC inhibited C. albicans planktonic growth at 0.5 mg/ml and virulence factors like yeast to hyphal form morphogenesis (0.0312 mg/ml), adhesion to polystyrene surface (0.0312 mg/ml) and biofilm formation (developing biofilm at 2 mg/ml and mature biofilm at 0.5 mg/ml) effectively. EITC blocked ergosterol biosynthesis and arrested C. albicans cells at S-phase. EITC caused ROS-dependent cellular death and nuclear or DNA fragmentation. EITC at 0.0312 mg/ml concentration regulated the expression of genes involved in the signal transduction pathway and inhibited yeast to hyphal form morphogenesis by upregulating TUP1, MIG1, and NRG1 by 3.10, 5.84 and 2.64-fold, respectively and downregulating PDE2 and CEK1 genes by 15.38 and 2.10-fold, respectively. EITC has showed haemolytic activity at 0.5 mg/ml concentration. In vivo study in silk worm model showed that EITC has toxicity to C. albicans at 0.5 mg/ml concentration. Thus, from present study we conclude that EITC has antifungal activity and to reduce its MIC and toxicity, combination study with other antifungal drugs need to be done. EITC and its combinations might be used as alternative therapeutics for the prevention and treatment of C. albicans infections.

Novel antimicrobial peptide DvAMP serves as a promising antifungal agent against Cryptococcus neoformans

Cryptococcus neoformans is an important opportunistic human fungal pathogen that causes cryptococcosis in immunocompromised patients. However, the number of drugs for the treatment of cryptococcosis is restricted, and the development of novel antifungal drugs and innovative strategies for the treatment of cryptococcosis is urgently needed. In this study, we validated that DvAMP is a novel antimicrobial peptide with antimicrobial activity and that it was obtained by pre-screening from the UniProt database of more than three million unknown functional sequences based on the quantitative structure-activity relationships (QSARs) protocol (http://www.chemoinfolab.com/antifungal). The peptide exhibited satisfactory biosafety and physicochemical properties, and relatively rapid fungicidal activity against C. neoformans. Meanwhile, DvAMP was able to inhibit the static biofilm of C. neoformans and cause a reduction in the thickness of the capsule. In addition, DvAMP exerts antifungal effects through membrane-mediated mechanisms (membrane permeability and depolarization) and mitochondrial dysfunction, involving a hybrid multi-hit mechanism. Furthermore, by using the C. neoformans-Galleria mellonella infection model, we demonstrated that DvAMP has significant therapeutic effects in vivo and that it significantly reduces the mortality and fungal burden of infected larvae. These results suggest that DvAMP may be a potential antifungal drug candidate for the treatment of cryptococcosis.

Emerging Polymer-Based Nanosystem Strategies in the Delivery of Antifungal Drugs

Nanosystems-based antifungal agents have emerged as an effective strategy to address issues related to drug resistance, drug release, and toxicity. Among the diverse materials employed for antifungal drug delivery, polymers, including polysaccharides, proteins, and polyesters, have gained significant attention due to their versatility. Considering the complex nature of fungal infections and their varying sites, it is crucial for researchers to carefully select appropriate polymers based on specific scenarios when designing antifungal agent delivery nanosystems. This review provides an overview of the various types of nanoparticles used in antifungal drug delivery systems, with a particular emphasis on the types of polymers used. The review focuses on the application of drug delivery systems and the release behavior of these systems. Furthermore, the review summarizes the critical physical properties and relevant information utilized in antifungal polymer nanomedicine delivery systems and briefly discusses the application prospects of these systems.

Primaquine, an antimalarial drug that controls the growth of cryptococcal cells

INTRODUCTION

The treatment of Cryptococcus neoformans with fluconazole and amphotericin B is, at times, characterised by clinical failure. Therefore, this study sought to re-purpose primaquine (PQ) as an anti-Cryptococcus compound.

METHOD

The susceptibility profile of some cryptococcal strains towards PQ was determined using EUCAST guidelines, and PQ's mode of action was examined. In the end, the ability of PQ to enhance in vitro macrophage phagocytosis was also assessed.

RESULTS

We show that PQ had a significant inhibitory effect on the metabolic activity of all tested cryptococcal strains, with 60 µM, defined as MIC₅₀ in this preliminary study, as it reduced the metabolic activity by more than 50%. Moreover, at this concentration, the drug was able to affect mitochondrial function adversely, as treated cells displayed significant (p < 0.05) loss of mitochondrial membrane potential, cytochrome c (cyt c) leakage and overproduction of reactive oxygen species (ROS) when compared to non-treated cells. It is our reasoned summation that the produced ROS targeted the cell walls and cell membranes, inducing observable ultrastructural changes and a significant (p < 0.05) increase in membrane permeability when compared to non-treated cells. Concerning the PQ effect on macrophages, it was noted that it significantly (p < 0.05) enhanced macrophage phagocytic efficiency compared to non-treated macrophages.

CONCLUSION

This preliminary study highlights the potential of PQ to inhibit the in vitro growth of cryptococcal cells. Moreover, PQ could control the proliferation of cryptococcal cells inside macrophages, which they often manipulate in a Trojan horse-like manner.

Cecropin D-derived synthetic peptides in the fight against Candida albicans cell filamentation and biofilm formation

The recent progressive increase in the incidence of invasive fungal infections, especially in immunocompromised patients, makes the search for new therapies crucial in the face of the growing drug resistance of prevalent nosocomial yeast strains. The latest research focuses on the active compounds of natural origin, inhibiting fungal growth, and preventing the formation of fungal biofilms. Antimicrobial peptides are currently the subject of numerous studies concerning effective antifungal therapy. In the present study, the antifungal properties of two synthetic peptides (ΔM3, ΔM4) derived from an insect antimicrobial peptide - cecropin D - were investigated. The fungicidal activity of both compounds was demonstrated against the yeast forms of Candida albicans, Candida tropicalis, and Candida parapsilosis, reaching a MFC_99.9 in the micromolar range, while Candida glabrata showed greater resistance to these peptides. The scanning electron microscopy revealed a destabilization of the yeast cell walls upon treatment with both peptides; however, their effectiveness was strongly modified by the presence of salt or plasma in the yeast environment. The transition of C. albicans cells from yeast to filamentous form, as well as the formation of biofilms, was effectively reduced by ΔM4. Mature biofilm viability was inhibited by a higher concentration of this peptide and was accompanied by increased ROS production, activation of the GPX3 and SOD5 genes, and finally, increased membrane permeability. Furthermore, both peptides showed a synergistic effect with caspofungin in inhibiting the metabolic activity of C. albicans cells, and an additive effect was also observed for the mixtures of peptides with amphotericin B. The results indicate the possible potential of the tested peptides in the prevention and treatment of candidiasis.

Lycopene, Mesoporous Silica Nanoparticles and Their Association: A Possible Alternative against Vulvovaginal Candidiasis?

Commonly found colonizing the human microbiota, Candida albicans is a microorganism known for its ability to cause infections, mainly in the vulvovaginal region known as vulvovaginal candidiasis (VVC). This pathology is, in fact, one of the main C. albicans clinical manifestations, changing from a colonizer to a pathogen. The increase in VVC cases and limited antifungal therapy make C. albicans an increasingly frequent risk in women's lives, especially in immunocompromised patients, pregnant women and the elderly. Therefore, it is necessary to develop new therapeutic options, especially those involving natural products associated with nanotechnology, such as lycopene and mesoporous silica nanoparticles. From this perspective, this study sought to assess whether lycopene, mesoporous silica nanoparticles and their combination would be an attractive product for the treatment of this serious disease through microbiological in vitro tests and acute toxicity tests in an alternative in vivo model of Galleria mellonella. Although they did not show desirable antifungal activity for VVC therapy, the present study strongly encourages the use of mesoporous silica nanoparticles impregnated with lycopene for the treatment of other human pathologies, since the products evaluated here did not show toxicity in the in vivo test performed, being therefore, a topic to be further explored.

Mechanism of Antifungal Action of Monoterpene Isoespintanol against Clinical Isolates of Candida tropicalis

The growing increase in infections by Candida spp., non-albicans, coupled with expressed drug resistance and high mortality, especially in immunocompromised patients, have made candidemia a great challenge. The efficacy of compounds of plant origin with antifungal potential has recently been reported as an alternative to be used. Our objective was to evaluate the mechanism of the antifungal action of isoespintanol (ISO) against clinical isolates of Candida tropicalis. Microdilution assays revealed fungal growth inhibition, showing minimum inhibitory concentration (MIC) values between 326.6 and 500 µg/mL. The eradication of mature biofilms by ISO was between 20.3 and 25.8% after 1 h of exposure, being in all cases higher than the effect caused by amphotericin B (AFB), with values between 7.2 and 12.4%. Flow cytometry showed changes in the permeability of the plasma membrane, causing loss of intracellular material and osmotic balance; transmission electron microscopy (TEM) confirmed the damage to the integrity of the plasma membrane. Furthermore, ISO induced the production of intracellular reactive oxygen species (iROS). This indicates that the antifungal action of ISO is associated with damage to membrane integrity and the induction of iROS production, causing cell death.

Ethanolic extract of Caesalpinia bonduc seeds triggers yeast metacaspase-dependent apoptotic pathway mediated by mitochondrial dysfunction through enhanced production of calcium and reactive oxygen species (ROS) in Candida albicans

Candida albicans is a widespread disease-causing yeast affecting humankind, which leads to urinary tract, cutaneous and various lethal systemic infections. As this infection rate steadily increases, it is becoming a significant public health problem. Recently, Caesalpinia bonduc has received much attention from researchers due to its diverse pharmacological properties, including antimicrobial effects. Accordingly, we first planned to explore the in-vitro anticandidal potential of three extracts obtained from C. bonduc seeds against four Candida species. Initially, the anticandidal activity of the seed extracts was checked by the microdilution technique. Out of three seed extracts tested, ethanolic extract of C. bonduc seed (EECS) recorded the best activity against C. albicans. Hence, we next aimed to find out the anticandidal mechanism of EECS in C. albicans. The liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) analysis showed that the major compounds present in the EECS were tocopherols, fucosterol, linoleic acid, β-amyrin, β-sitosterol, campesterol, cassane furanoditerpene, Norcassane furanoditerpene and other diterpenes. To evaluate the cell death mechanism in C. albicans, a series of parameters related to apoptosis, viz., reactive oxygen species (ROS) production, membrane permeability, mitochondrial membrane potential, release of cytochrome c, DNA fragmentation, nuclear condensation, increased Ca²⁺ level in cytosolic and mitochondrial and activation of metacaspase, were analyzed. The results showed that EECS treatment resulted in the elevation of ROS, which leads to plasma membrane permeability in C. albicans. Annexin V staining further confirms the early stage of apoptosis through phosphatidylserine (PS) externalization. We further inspected the late apoptotic stage using DAPI and TUNEL staining assays. From the results, it can be concluded that EECS triggered mitochondrial dysfunction by releasing high levels of ROS, cytochrome c and Ca²⁺resulting in the activation of metacaspase mediated apoptosis, which is the central mechanism behind the cell death of C. albicans. Finally, a Galleria mellonella-C. albicans infection system was employed to assess the in-vivo potential of EECS. The outcomes displayed that the EECS considerably enhanced the recovery rate of G. mellonella larvae from infection after the treatment. Additionally, EECS also recorded low hemolytic activity. This study thus spotlights the anticandidal potential and mechanism of action of EECS against C. albicans and thus delivers a promising treatment approach to manage C. albicans infection in the future.

Paeonol triggers apoptosis in HeLa cervical cancer cells: the role of mitochondria-related caspase pathway

Paeonol is a biologically active component purified from the root bark of Cortex Moutan that exerts pharmacological effects on the cervical cancer. In this study, we aim to evaluate the anti-cervical cancer capacity of paeonol and to investigate the mechanism driving its anti-cervical cancer effect. Paeonol administration markedly restrained the proliferation and caused apoptosis in HeLa cells. Furthermore, paeonol treatment resulted in a mitochondrial dysfunction in HeLa cells, including the inducing of mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production, and the release of cytochrome c. Moreover, the Bcl-2/Bax proportion was obviously downregulated and cleaved caspase-3 expression was evaluated through paeonol treatment. Additionally, the expression of p-PI3K and p-Akt was noticeably reduced in response to paeonol treatment in HeLa cells. Our findings indicated that paeonol exerts an anticancer potential in HeLa cells, at least in a manner, via triggering the mitochondrial pathway of cellular apoptosis by inhibiting PI3K/Akt signaling. Thus, paeonol has great potential as a promising therapeutic compound to resist human cervical cancer.

Natural food flavour (E)-2-hexenal, a potential antifungal agent, induces mitochondria-mediated apoptosis in Aspergillus flavus conidia via a ROS-dependent pathway

Natural food flavour (E)-2-hexenal, a green leaf volatile, exhibits potent antifungal activity on Aspergillus flavus, but its antifungal mechanism has not been fully elucidated. In this study, we evaluated (E)-2-hexenal-induced apoptosis in A. flavus conidia and explored the underlying mechanisms of action. Evidence of apoptosis in A. flavus conidia were investigated by methods including fluorescent staining, flow cytometry, confocal laser scanning microscope, and spectral analysis. Results indicated that 4.0 μL/mL (minimum fungicidal concentration, MFC) of (E)-2-hexenal application induced early markers of apoptotic cell death in A. flavus conidia with a rate of 38.4% after 6 h exposure. Meanwhile, typical hallmarks of apoptosis, such as decreased mitochondrial membrane potential (MMP), activated metacaspase activity, fragmented DNA, mitochondrial permeability transition pore (MPTP) opening and cytochrome c (Cyt C) release from mitochondria to the cytosol were also confirmed. Furthermore, intracellular ATP levels were reduced by 63.3 ± 3.6% and reactive oxygen species (ROS) positive cells increased by 31.1 ± 3.1% during A. flavus apoptosis induced by (E)-2-hexenal. l-Cysteine (Cys), an antioxidant, could strongly block the excess ROS generation caused by (E)-2-hexenal, which correspondingly resulted in a significant inhibition of MPTP opening and decrease of apoptosis in A. flavus, indicating that ROS palys a pivotal role in (E)-2-hexenal-induced apoptosis. These results suggest that (E)-2-hexenal exerts its antifungal effect on A. flavus conidia via a ROS-dependent mitochondrial apoptotic pathway.

Evaluation of the antifungal effect of chlorogenic acid against strains of Candida spp. resistant to fluconazole: apoptosis induction and in silico analysis of the possible mechanisms of action

Introduction. Candida spp. are commensal fungal pathogens of humans, but when there is an imbalance in the microbiota, or weak host immunity, these yeasts can become pathogenic, generating high medical costs.Gap Statement. With the increase in resistance to conventional antifungals, the development of new therapeutic strategies is necessary. This study evaluated the in vitro antifungal activity of chlorogenic acid against fluconazole-resistant strains of Candida spp. Mechanism of action through flow cytometry and in silico analyses, as well as molecular docking assays with ALS3 and SAP5, important proteins in the pathogenesis of Candida albicans associated with the adhesion process and biofilm formation.Results. The chlorogenic acid showed in vitro antifungal activity against the strains tested, causing reduced cell viability, increased potential for mitochondrial depolarization and production of reactive oxygen species, DNA fragmentation and phosphatidylserine externalization, indicating an apoptotic process. Concerning the analysis through docking, the complexes formed between chlorogenic acid and the targets Thymidylate Kinase, CYP51, 1Yeast Cytochrome BC1 Complex e Exo-B-(1,3)-glucanase demonstrated more favourable binding energy. In addition, chlorogenic acid presented significant interactions with the ALS3 active site residues of C. albicans, important in the adhesion process and resistance to fluconazole. Regarding molecular docking with SAP5, no significant interactions were found between chlorogenic acid and the active site of the enzyme.Conclusion. We concluded that chlorogenic acid has potential use as an adjuvant in antifungal therapies, due to its anti-Candida activity and ability to interact with important drug targets.

The Inhibitory Activity of Citral against Malassezia furfur

The lipophilic yeast Malassezia furfur, is a member of the cutaneous commensal microbiota and is associated with several chronic diseases such as dandruff, pityriasis versicolor, folliculitis, and seborrheic dermatitis, that are often difficult to treat with current therapies. The development of alternatively effective antifungal therapies is therefore of paramount importance. In this study, we investigated the treatment effect of citral on M. furfur. The minimal inhibitory concentration of citral for M. furfur was 200 μg/mL, and the minimal fungicidal concentration was 300 μg/mL. Citral significantly increased the proportion of yeast cells to mycelial forms 2.6-fold. Phosphatidylserine externalization, DNA fragmentation, and metacaspase activation supported a citral-induced apoptosis in M. furfur. Moreover, citral at sub-minimum inhibitory concentrations reduced the invasion of M. furfur in HaCaT keratinocytes. Finally, we demonstrated that citral inhibited IL-6 and TLR-2 expression and enhanced HBD-2 and TSLP expression in M. furfur-infected HaCaT keratinocytes. These results showed that citral has antifungal activity at high concentrations and can decrease the infection of M. furfur by modulating the keratinocyte immune responses at low concentrations. Our results suggest that citral is a potential candidate for topical therapeutic application for M. furfur-associated human skin diseases.

Antifungal activity of puroindoline protein from soft wheat against grain molds and its potential as a biocontrol agent

Mold growth reduces the quality of stored grains, besides producing toxins that pose a potential threat to human health. Therefore, prevention of grain mold growth during storage is important to ensure a safe and high-quality product, preferably using an eco-friendly antifungal agent. The Puroindoline (PIN) protein was extracted by Triton X-114, and identified by QE mass spectrometry. A. flavus has attracted much attention because of its toxic secondary metabolites, and PIN protein showed a significant inhibition on A. flavus growth. Scanning electron microscopy revealed altered spore morphology of A. flavus following PIN protein treatment, and propidium iodide staining showed incomplete spore cell membranes. The disruption and deformation of A. flavus spores suggest that the cell walls and cell membranes were compromised. Decreased mitochondrial membrane potential and increased levels of intracellular reactive oxygen species (ROS) were detected using JC-1 and 2,7-dichlorodihydrofluorescein diacetate staining, respectively. PIN protein could effectively inhibit the growth and aflatoxins B1 production of A. flavus in stored grains, such as wheat and rice. PIN proteins can inhibit the growth of many common grain storage molds, including Penicillium, Aspergillus spp. (A. flavus, A. glaucus, A. kawachii, A. ochraceus, A. niger), Alternaria, and Fusarium graminearum, in a dose-dependent manner. PIN protein has a significant inhibitory effect on the growth of grain molds, with a stronger inhibitory effect noted in wheat and rice. Our study provides a novel and simple theoretical basis for the selection and storage of mold-resistant in grains and food during storage.

Bio-Availability, Anticancer Potential, and Chemical Data of Lycopene: An Overview and Technological Prospecting

The purpose of this review was to collect relevant chemical data about lycopene and its isomers, which can be extracted using different non-polar or polar aprotic solvents by SC-CO₂ or biosynthesis as a friendly technique. Lycopene and other carotenoids can be identified and quantified by UV–Vis and HPLC using a C18 or C30 column, while their characterization is possible by UV–Vis, Fluorescence, FTIR, MS, NMR, and DSC assays. Among these techniques, the last four can compare lycopene isomers and identify cis or all-trans-lycopene. FTIR, MS, and NMR techniques are more suitable for the verification of the purity of lycopene extracts due to the signal complexity generated for each isomer, which enables identification by subtle differences. Additionally, some biological activities of lycopene isolated from red vegetables have already been confirmed, such as anti-inflammatory, antioxidant, and cytotoxic activity against cancer cells, probably by activating several pathways. The encapsulation of lycopene in nanoparticles demonstrated an improvement in oral delivery, and ex vivo assessments determined that these nanoparticles had better permeation and low cytotoxicity against human cells with enhanced permeation. These data suggest that lycopene has the potential to be applied in the food and pharmaceutical industries, as well as in cosmetic products.

Essential Oils Prime Epigenetic and Metabolomic Changes in Tomato Defense Against Fusarium oxysporum

In this work, we studied the direct and indirect plant protection effects of an Artemisia absinthium essential oil (AEO) on tomato seedlings against Fusarium oxysporum sp. oxysporum radicis lycopersici (Fol). AEO exhibited a toxic effect in vitro against Fol. Additionally, tomato seedlings germinated from seeds pretreated with AEO and grown hydroponically were protected against Fol. Plant disease symptoms, including, water and fresh weight loss, tissue necrosis, and chlorosis were less pronounced in AEO-treated seedlings. AEO also contributed to plant defenses by increasing callose deposition and the production of reactive oxygen species (ROS) on seed surfaces without affecting seed germination or plant development. The essential oil seed coating also primed a durable tomato seedling defense against the fungus at later stages of plant development. RNA-seq and metabolomic analysis performed on seedlings after 12 days showed that the AEO treatment on seeds induced transcriptomic and metabolic changes. The metabolomic analysis showed an induction of vanillic acid, coumarin, lycopene, oleamide, and an unknown metabolite of m/z 529 in the presence of Fol. The StNRPD2 gene, the second largest component of RNA polymerases IV and V directly involved in de novo cytosine methylation by RNA-directed DNA methylation (RdDM), was highly induced in the presence of AEO. The host methionine cycle (MTC) controlling trans-methylation reactions, was also altered by AEO through the high induction of S-adenosyl methionine transferases (SAMts). Our results suggest that AEO treatment could induce de novo epigenetic changes in tomato, modulating the speed and extent of its immune response to Fol. The EO-seed coating could be a new strategy to prime durable tomato resistance, compatible with other environmentally friendly biopesticides.

Acetylated cashew gum and fucan for incorporation of lycopene rich extract from red guava (Psidium guajava L.) in nanostructured systems: Antioxidant and antitumor capacity

Industrial application of lycopene is limited due to its chemical instability and low bioavailability. This study proposes the development of fucan-coated acetylated cashew gum nanoparticles (NFGa) and acetylated cashew gum nanoparticles (NGa) for incorporation of the lycopene-rich extract from red guava (LEG). Size, polydispersity, zeta potential, nanoparticles concentration, encapsulation efficiency, transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to characterize nanoparticles. The antioxidant activity was determinated and cell viability was evaluated in the human breast cancer cells (MCF-7) and human keratinocytes (HaCaT) by MTT assay. The toxic effect was evaluated by hemolysis test and by Galleria mellonella model. NFGa showed higher stability than NGa, having a size of 162.10 ± 3.21 nm, polydispersity of 0.348 ± 0.019, zeta potential -30.70 ± 0.53 mV, concentration of 6.4 × 10⁹ nanoparticles/mL and 60% LEG encapsulation. Microscopic analysis revealed a spherical and smooth shape of NFGa. NFGa showed antioxidant capacity by ABTS method and ORAC assay. The NFGa presented significant cytotoxicity against MCF-7 from the lowest concentration tested (6.25-200 μg/mL) and did not affect the cell viability of the HaCaT. NFGa showed non-toxic effect in the in vitro and in vivo models. Therefore, NFGa may have a promising application in LEG stabilization for antioxidant and antitumor purposes.

Investigation of distinct contribution of nitric oxide and each reactive oxygen species in indole-3-propionic-acid-induced apoptosis-like death in Escherichia coli

AIMS

Indole-3-propionic acid (IPA) is a natural product from human microbiota, exhibiting diverse biological activities. The study focused on investigating the antibacterial mode of action(s) triggered by IPA in Escherichia coli. Separate influence of nitric oxide (NO) and each reactive oxygen species, including superoxide anion (O₂^-), hydrogen peroxide (H₂O₂), hydroxyl radical (OH^-), was specifically analyzed throughout the process.

MAIN METHODS

The generation of respective reactive oxygen species (ROS), NO, and ONOO^- was conducted using flow cytometer using different dyes. Further analysis of separate influences was held based on usage of each scavenger: sodium pyruvate, thiourea, tiron, and L-NAME. Oxidative cell damage was observed through the detection of glutathione depletion and lipid peroxidation. DNA fragmentation and membrane depolarization were observed by TUNEL and DiBAC₄(3) staining agent. Finally, Annexin V/PI and FITC-VAD-FMK were applied to detect apoptosis-like death.

KEY FINDINGS

IPA exhibited antibacterial activity in E. coli through the accumulation of ROS, NO, ONOO^-, and DNA damage, eventually leading to apoptosis-like death. NO and O₂^- exerted the most potent influence on oxidative damage of E. coli, whereas H₂O₂ accounts for the least impact. Moreover, the results reveal the major contribution of ONOO^- in IPA-induced apoptosis-like death in E. coli.

SIGNIFICANCE

This is the first study that introduces the antibacterial activity and apoptosis-like death induced by IPA and suggests the possibility of being an alternative for current antibiotics. Furthermore, the distinct influence of each ROS and NO was analyzed to investigate their contribution to oxidative damage leading to bacterial apoptosis-like death.

Striking Back against Fungal Infections: The Utilization of Nanosystems for Antifungal Strategies

Fungal infections have become a major health concern, given that invasive infections by Candida, Cryptococcus, and Aspergillus species have led to millions of mortalities. Conventional antifungal drugs including polyenes, echinocandins, azoles, allylamins, and antimetabolites have been used for decades, but their limitations include off-target toxicity, drug-resistance, poor water solubility, low bioavailability, and weak tissue penetration, which cannot be ignored. These drawbacks have led to the emergence of novel antifungal therapies. In this review, we discuss the nanosystems that are currently utilized for drug delivery and the application of antifungal therapies.

Recent progress on anti-Candida natural products

Candida is an intractable life-threatening pathogen. Candida infection is extremely difficult to eradicate, and thus is the major cause of morbidity and mortality in immunocompromised individuals. Morevover, the rapid spread of drug-resistant fungi has led to significant decreases in the therapeutic effects of clinical drugs. New anti-Candida agents are urgently needed to solve the complicated medical problem. Natural products with intricate structures have attracted great attention of researchers who make every endeavor to discover leading compounds for antifungal agents. Their novel mechanisms and diverse modes of action expand the variety of fungistatic agents and reduce the emergence of drug resistance. In recent decades, considerable effort has been devoted to finding unique antifungal agents from nature and revealing their unusual mechanisms, which results in important progress on the development of new antifungals, such as the novel cell wall inhibitors YW3548 and SCY-078 which are being tested in clinical trials. This review will present a brief summary on the landscape of anti-Candida natural products within the last decade. We will also discuss in-depth the research progress on diverse natural fungistatic agents along with their novel mechanisms.

Apoptosis-like death-inducing property of tachyplesin I in Escherichia coli

 Antimicrobial peptide (AMP) derived from the horseshoe crab, tachyplesin I (KWCFRVCYRGICYRRCR-NH₂ ), displayed the apparent antimicrobial activity with low cytotoxicity, suggesting its efficacy as an attractive agent but still lacks the understandings regarding its mechanism(s). Hence, the study focused on investigating the antibacterial mode of action of tachyplesin I against Escherichia coli. Based on the reactive oxygen species generation displayed in several antimicrobial effects, the detection of superoxide anion and nitric oxide were verified after tachyplesin I treatment. Substantial increment of two molecules was followed by the imbalance in intracellular ion concentration, noticeably magnesium and calcium. The series of stages led to hydroxyl radical generation with reduced glutathione, followed by damage in DNA due to oxidative stress. Eventually, the apoptosis-like death in E. coli was monitored in DNA fragmentation-dependent manner due to the tachyplesin I treatment, verified by membrane depolarization, caspase-like protein activation, and phosphatidylserine exposure. Accordingly, tachyplesin I induces apoptosis-like death in E. coli, suggesting the potential of being a candidate for regulating bacterial infection.

The inhibitory activity of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) on Candida albicans biofilms

BACKGROUND

Biofilm-associated Candida albicans (C. albicans) infections are hard to cure due to their high levels of resistance to antifungal agents. Photodynamic therapy (PDT) is a promising approach for controlling infections caused by C. albicans. This study was designed to explore the inhibitory activity of PDT using 5-aminolevulinic acid (ALA) as photosensitizer against C. albicans biofilms.

METHODS

C. albicans cell suspensions were incubated for 48 h to form mature biofilms. ALA solution was diluted to 15 mM and incubated with C. albicans biofilms for 5 h before irradiated by red light semiconductor laser under the light intensity of 300 J/cm² and fluence rate of 100 mW/cm² for 50 min. The inhibitory activity was evaluated from subcellular level, molecular level and transcriptional level using transmission electron microscopy (TEM) observation, flow cytometry analysis and quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) assays, respectively.

RESULTS

From subcellular level, the degraded content of the cytoplasm, nuclear condensation and mitochondrial swelling were observed after ALA-PDT. From molecular level, ALA-PDT resulted in 19.4 % cell apoptosis. From transcriptional level, ALA-PDT significantly reduced the mRNA expressions of hyphae-specific genes (HWP1 and ALS3) and long-term biofilm maintenance genes (UME6 and HGC1), whereas ALA or red light alone had no significant effect.

CONCLUSIONS

The inhibitory activity indicated that ALA-PDT may have the potential to serve as an antifungal strategy in eliminatingC. albicans biofilms.

Highlighting the use of micro and nanoparticles based-drug delivery systems for the treatment of Helicobacter pylori infections

Due to the high adaptability of Helicobacter pylori and the low targeting specificity of the drugs normally used in pharmacological therapy, the strains are becoming increasingly resistant to these drugs, making it difficult to eradicate the infection. Thus, the search for new therapeutic approaches has been considered urgent. The incorporation of drugs in advanced drug delivery systems, such as nano and microparticles, would allow the improvement of the retention time in the stomach and the prolongation of drug release rates at the target site. Because of this, the present review article aims to highlight the use of micro and nanoparticles as important technological tools for the treatment of H. pylori infections, focussing on the main nanotechnological systems, including nanostructured lipid carriers, liposomes, nanoemulsion, metallic nanoparticles, and polymeric nanoparticles, as well as microtechnological systems such as gastroretentive dosage forms, among them mucoadhesive, magnetic and floating systems were highlighted.

Reactive oxygen mediated apoptosis as a therapeutic approach against opportunistic Candida albicans

Candida albicans are polymorphic fungal species commonly occurs in a symbiotic association with the host's usual microflora. Certain specific changes in its usual microenvironment can lead to diseases ranging from external mucosal to severally lethal systemic infections like invasive candidiasis hospital-acquired fatal infection caused by different species of Candida. The patient acquired with this infection has a high mortality and morbidity rate, ranging from 40% to 60%. This is an ill-posed problem by its very nature. Hence, early diagnosis and management is a crucial part. Antifungal drug resistance against the first and second generation of antifungal drugs has made it difficult to treat such fatal diseases. After a few dormant years, recently, there has been a rapid turnover of identifying novel drugs with low toxicity to limit the problem of drug resistance. After an initial overview of related work, we examine specific prior work on how a change in oxidative stress can facilitate apoptosis in C. albicans. Subsequently, it was investigated that Candida spp. suppresses the production of ROS mediated host defense system. Here, we have reviewed possibly all the small molecule inhibitors, natural products, antimicrobial peptide, and some naturally derived semi-synthetic compounds which are known to influence oxidative stress, to generate a proper apoptotic response in C. albicans and thus might be a novel therapeutic approach to augment the current treatment options.

Reversal of azole resistance in Candida albicans by oridonin

OBJECTIVES

Candida albicans is a yeast that causes fungal infections with high mortality and is typically resistant to azole drugs. To overcome this resistance, we explored the combined use of oridonin (ORI) and three azole drugs, namely fluconazole (FLC), itraconazole (ITR) and voriconazole (VOR). Azole-resistant C. albicans strains were obtained from cancer patients and the reversal of drug resistance in these strains was investigated.

METHODS

The synergistic antifungal activity of ORI and azole drugs was measured by checkerboard microdilution and time-kill assays. The resistance reversal mechanisms, namely inhibition of drug efflux and induction of apoptosis, were investigated by flow cytometry. Expression levels of the efflux pump-related genesCDR1 and CDR2 were assessed by RT-qPCR.

RESULTS

The efflux pump inhibition assay with ORI showed that the minimum inhibitory concentrations (MICs) of FLC (128-fold), ITR (64-fold) and VOR (250-fold) decreased significantly. Upregulation of genes encodingCDR1 and CDR2 was confirmed in the resistant strain. The sensitising effect of ORI on FLC in the treatment of C. albicans also included the promotion of apoptosis.

CONCLUSION

We demonstrated that combining azoles with ORI exerted potent synergism and that ORI could promote sensitisation to azoles in azole-resistantC. albicans. The discovery that ORI can effectively inhibit drug efflux and promote apoptosis may provide new insights and therapeutic strategies to overcome increasing azole resistance in C. albicans.

Evaluation of the antifungal activity in vitro of midazolam against fluconazole-resistant Candida spp. isolates

Aim: The purpose of this study was to evaluate the antifungal activity of midazolam, alone and in association with azoles, against isolates of clinical Candida spp. in planktonic and biofilm form. Materials & methods: The antifungal activity was observed using the broth microdilution technique. Flow cytometry tests were performed to investigate the probable mechanism of action and the comet test and cytotoxicity test were applied to evaluate DNA damage. Results: Midazolam (MIDAZ) showed antifungal activity against planktonic cells (125-250 μg/ml) and reduced the viability of Candida spp. biofilms (125 a 2500 μg/ml). The interaction of MIDAZ against Candida spp. biofilms was observed through scanning electron microscopy, causing alteration of their appearance. Therefore, MIDAZ has antifungal potential against Candida spp.

The use of plant extracts and their phytochemicals for control of toxigenic fungi and mycotoxins

Mycotoxins present a great concern to food safety and security due to their adverse health and socio-economic impacts. The necessity to formulate novel strategies that can mitigate the economic and health effects associated with mycotoxin contamination of food and feed commodities without any impact on public health, quality and nutritional value of food and feed, economy and trade industry become imperative. Various strategies have been adopted to mitigate mycotoxin contamination but often fall short of the required efficacy. One of the promising approaches is the use of bioactive plant components/metabolites synergistically with mycotoxin-absorbing components in order to limit exposure to these toxins and associated negative health effects. In particular, is the fabrication of β-cyclodextrin-based nanosponges encapsulated with bioactive compounds of plant origin to inhibit toxigenic fungi and decontaminate mycotoxins in food and feed without leaving any health and environmental hazard to the consumers. The present paper reviews the use of botanicals extracts and their phytochemicals coupled with β-cyclodextrin-based nanosponge technology to inhibit toxigenic fungal invasion and detoxify mycotoxins.

Antifungal activity of β-lapachone against azole-resistant Candida spp. and its aspects upon biofilm formation

Aim: The purpose of this study was to assess the antifungal effect of β-lapachone (β-lap) on azole-resistant strains of Candida spp. in both planktonic and biofilm form. Materials & methods: The antifungal activity of β-lap was evaluated by broth microdilution, flow cytometry and the comet assay. The cell viability of the biofilms was assessed using the MTT assay. Results: β-lap showed antifungal activity against resistant strains of Candida spp. in planktonic form. In addition, β-lap decreased the viability of mature biofilms and inhibited the formation of biofilms in vitro. Conclusion: β-lap showed antifungal activity against Candida spp., suggesting that the compound can be utilized as an adjunct agent in the treatment of candidiasis.

Plant-Derived Substances in the Fight Against Infections Caused by Candida Species

Yeast-like fungi from the Candida genus are predominantly harmless commensals that colonize human skin and mucosal surfaces, but under conditions of impaired host immune system change into dangerous pathogens. The pathogenicity of these fungi is typically accompanied by increased adhesion and formation of complex biofilms, making candidal infections challenging to treat. Although a variety of antifungal drugs have been developed that preferably attack the fungal cell wall and plasma membrane, these pathogens have acquired novel defense mechanisms that make them resistant to standard treatment. This causes an increase in the incidence of candidiasis and enforces the urgent need for an intensified search for new specifics that could be helpful, alone or synergistically with traditional drugs, for controlling Candida pathogenicity. Currently, numerous reports have indicated the effectiveness of plant metabolites as potent antifungal agents. These substances have been shown to inhibit growth and to alter the virulence of different Candida species in both the planktonic and hyphal form and during the biofilm formation. This review focuses on the most recent findings that provide evidence of decreasing candidal pathogenicity by different substances of plant origin, with a special emphasis on the mechanisms of their action. This is a particularly important issue in the light of the currently increasing frequency of emerging Candida strains and species resistant to standard antifungal treatment.

Nanosystems against candidiasis: a review of studies performed over the last two decades

The crescent number of cases of candidiasis and the increase in the number of infections developed by non-albicans species and by multi-resistant strains has taken the attention of the scientific community, which has been searching for new therapeutic alternatives. Among the alternatives found the use of nanosystems for delivery of drugs already commercialized and new biomolecules have grown, in order to increase stability, solubility, optimize efficiency and reduce adverse effects. In view of the growing number of studies involving technological alternatives for the treatment of candidiasis, the present review came with the intention of gathering studies from the last two decades that used nanotechnology for the treatment of candidiasis, as well as analysing them critically and pointing out the future perspectives for their application with this purpose. Different studies were considered for the development of this review, addressing nanosystems such as metallic nanoparticles, mesoporous silica nanoparticles, polymeric nanoparticles, liposomes, nanoemulsion, microemulsion, solid lipid nanoparticle, nanostructured lipid carrier, lipidic nanocapsules and liquid crystals; and different clinical presentations of candidiasis. As a general overview, nanotechnology has proven to be an important ally for the treatment against the diversity of candidiasis found in the clinic, whether in increasing the effectiveness of commercialized drugs and reducing their adverse effects, as well as allowing exploring more effectively properties therapeutics of new biomolecules.

Ocotea glomerata (Nees) Mez Extract and Fractions: Chemical Characterization, Anti-Candida Activity and Related Mechanism of Action

Background: Opportunistic fungal infections are increasingly common, with Candida albicans being the most common etiological agent; however, in recent years, episodes of candidiasis caused by non-albicansCandida species have emerged. Plants belonging to the Lauraceae family have shown remarkable antifungal effects. This study assessed the anti-Candida activity of Ocotea glomerata extracts and fractions, time of death and the synergistic effects with conventional antifungals. The possible mechanism of action was also addressed. Methods: Minimal inhibitory concentrations (MIC) were determined by broth microdilution technique, and the mechanism of action was assessed by ergosterol, sorbitol, cell viability, reactive oxygen species (ROS) generation and phosphatidylserine externalization tests. Results: All the tested extracts evidenced antifungal activity, but the methanol extract was revealed to be the most effective (MIC = 3.12 μg/mL) on C. krusei. The combination of methanol extract with ketoconazole and fluconazole revealed a synergistic effect for C. krusei and C. albicans, respectively. Fractions 1 and 5 obtained from the methanol extract had fungicidal activity, mainly against C. krusei. Methanol extract did not reveal effects by ergosterol and sorbitol assays; however, it led to an increase in intracellular ROS levels, decreased cell viability, and consequently, cell death. Conclusion: O. glomerata methanol extract may be viewed as a rich source of biomolecules with antifungal activity against Candida spp.

An Overview of Properties and Analytical Methods for Lycopene in Organic Nanocarriers

Lycopene (LYC), a natural compound responsible for the red color of some fruits like pink grapefruit, red guava, watermelon, papaya and, mainly, present in tomatoes (Solanum lycopersicum). LYC has been extensively studied because of its various pharmacological properties such as antioxidant, cardioprotective, hypocholesterolemic, antineophasic, photoprotection, antidiabetic and antimicrobial activity. However, LYC uses in therapy is limited due to its insolubility in aqueous solvents, resulting in low bioavailability and stability. In order to overcome these drawbacks, it is essential to use of organic nanocarriers for LYC controlled release. Up to now, the description of LYC-loaded organic nanocarriers are scarce, mainly related to organic nanosystems based on lipid nanostructures such as nanoemulsions (NE), liposomes (LP), niosomes (NI), nanostructured lipid carriers (NLC) and solid lipid nanoparticles (SLN). Taking into account the development of new formulations, is indispensable the use of sensitive and suitable analytical methods previously validated. Among the analytical methods described here, high-performance liquid chromatography (HPLC) stands out due to its good accuracy, precision and desirable detection limit. In this review, we highlights the main biological and physicochemical properties of LYC, as well as LYC-based organic nanocarriers for controlled drug delivery and the analytical methods described in literature to determine LYC in any kind of matrix.

Role of membrane sterol and redox system in the anti-candida activity reported for Mo-CBP2, a protein from Moringa oleifera seeds

Plant proteins are emerging as an alternative to conventional treatments against candidiasis. The aim of this study was to better understand the mechanism of action of Mo-CBP₂ against Candida spp, evaluating redox system activity, lipid peroxidation, DNA degradation, cytochrome c release, medium acidification, and membrane interaction. Anti-candida activity of Mo-CBP₂ decreased in the presence of ergosterol, which was not observed with antioxidant agents. C. albicans treated with Mo-CBP₂ also had catalase and peroxidase activities inhibited, while superoxide dismutase was increased. Mo-CBP₂ increased the lipid peroxidation, but it did not alter the ergosterol profile in live cells. External medium acidification was strongly inhibited, and cytochrome c release and DNA degradation were detected. Mo-CBP₂ interacts with cell membrane constituents, changes redox system enzymes in C. albicans and causes lipid peroxidation by ROS overproduction. DNA degradation and cytochrome c release suggest apoptotic or DNAse activity. Lipid peroxidation and H⁺-ATPases inhibition may induce the process of apoptosis. Finally, Mo-CBP₂ did not have a cytotoxic effect in mammalian Vero cells. This study highlights the biotechnological potential of Mo-CBP₂ as a promising molecule with low toxicity and potent activity. Further studies should be performed to better understand its mode of action and toxicity.

Chemopreventive Effect of β-Cryptoxanthin on Human Cervical Carcinoma (HeLa) Cells Is Modulated through Oxidative Stress-Induced Apoptosis

The present study was aimed to assess cellular and molecular events involved in the chemopreventive activities of β-cryptoxanthin derived from mandarin oranges (Citrus unshiu Marc.) on human cervical carcinoma (HeLa) cells. In vitro experiments established that β-cryptoxanthin significantly inhibited the proliferation of HeLa cells with the IC₅₀ value of 4.5 and 3.7 µM after 24 and 48 h of treatments, respectively. β-cryptoxanthin-treated HeLa cells exhibited enhanced levels of oxidative stress correlated with significant downregulation of anti-apoptotic Bcl-2, and upregulation of pro-apoptotic Bax mRNA expression. Moreover, β-cryptoxanthin triggered nuclear condensation and disruption of the integrity of the mitochondrial membrane, upregulated caspase-3, -7, and -9 mRNA, and enhanced activation of caspase-3 proteins, resulting in nuclei DNA damage and apoptosis of HeLa cells. Remarkably, TUNEL assay carried out to detect nuclei DNA damage showed 52% TUNEL-positive cells after treatment with a physiological concentration of β-cryptoxanthin (1.0 μM), which validates its potential as an anticancer drug of natural origin.

Antifungal Activity of Coumarin Against Candida albicans Is Related to Apoptosis

Coumarin (1,2-benzopyrone), an aromatic oxygen-containing heterocyclic compound, has various biological functions. Previous studies have demonstrated that coumarin and its derivatives exhibit antifungal activity against Candida albicans. In this study, we investigated the exact mechanism by which coumarin works against this fungus using Annexin V-FITC/PI double staining, TUNEL assay, and DAPI staining, and found that it induced a series of apoptotic features, including phosphatidylserine (PS) externalization, DNA fragmentation, and nuclear condensation. Moreover, it also induced cytochrome c release from the mitochondria to the cytoplasm and metacaspase activation. Further study revealed that intracellular reactive oxygen species (ROS) levels were increased and mitochondrial functions, such as mitochondrial membrane potential and mitochondrial morphology, were altered after treatment with coumarin. Cytosolic and mitochondrial Ca²⁺ levels were also found to be elevated. However, pretreatment with ruthenium red (RR), a known mitochondrial Ca²⁺ channel inhibitor, attenuated coumarin-mediated DNA fragmentation and metacaspase activity, indicating that the coumarin-induced C. albicans apoptosis is associated with mitochondrial Ca²⁺ influx. Finally, coumarin was found to be low-toxic and effective in prolonging the survival of C. albicans-infected mice. This study highlights the antifungal activity and mechanism of coumarin against C. albicans and provides a potential treatment strategy for C. albicans infection.

Sophorolipid exhibits antifungal activity by ROS mediated endoplasmic reticulum stress and mitochondrial dysfunction pathways in Candida albicans

In the present study, we investigated the mechanism of cell death in C. albicans due to treatment with sophorolipid (SL). SL is an extracellular glycolipid biosurfactant produced by various species of non-pathogenic yeasts and is known to inhibit the growth and biofilm formation of C. albicans. This study revealed that treatment of C. albicans cells with SL increases the ROS production and expression of oxidative stress-related genes significantly (SOD1, CAT1). Increased ROS level within the cells causes ER stress and release of Ca²⁺ in the cytoplasm and alteration of the mitochondrial membrane potential (MMP). Quantitative real time-polymerase chain reaction (qRT-PCR) data showed that SL also upregulates the Endoplasmic Reticulum (ER) stress marker HAC1. Flow cytometric analysis (AnnexinV/PI) indicated that the cell death may have occurred due to necrosis which was further confirmed by LDH release assay and transmission electron microscopy (TEM). Further experiments with the null mutant Δ hog1 strain of C. albicans SC5314 indicated the activation of the osmotic stress response pathway (HOG-MAPK) and SAP9. This study gave an insight into the mechanism of cell death initiation by glycolipids and indicated that further modification of these molecules can lead to the development of new therapeutic agent against C. albicans.

Sophorolipid induces ROS generation in C. albicans leading to mitochondrial dysfunction and ER stress followed by the release of Ca²⁺ ions (from the ER lumen) that enter mitochondria and further magnify ROS generation leading to cell death.

In vitro and in vivo antitumor potential of carvacrol nanoemulsion against human lung adenocarcinoma A549 cells via mitochondrial mediated apoptosis

Carvacrol is present abundantly in the essential oils of many medicinal plants and well known for its numerous biological activities. Since partial solubility in water and physicochemical instability limits its industrial uses, the present study was performed to prepare a carvacrol nanoemulsion (CANE) using an ultrasonication technique and further evaluation of its anticancer potential against human lung adenocarcinoma A549 cells. The nanoemulsion formulation was optimized by varying carvacrol and polysorbate 80 ratios and characterized by dynamic light scattering (DLS), which revealed a negative surface charge with a mean droplet size between 105.5 ± 3.4 to 169.8 ± 4.9 nm. The CANE induced reactive oxygen species (ROS) production in A549 cells, leading to activation of key regulators of apoptosis such as p-JNK, Bax and Bcl2 as well as release of cytochrome C, and activation of the caspase cascade. Suppression of mitochondrial ROS using Mito-TEMPO reversed the apoptotic potential of CANE signifying involvement of mitochondrial ROS in cell death. Beside, CANE displayed a strong antitumor potential in vivo using an athymic nude mice model. The results strongly support that CANE induced apoptosis in A549 cells by induction of ROS and could be a promising candidate for lung cancer therapy.

Reactive oxygen species modulate itraconazole-induced apoptosis via mitochondrial disruption in Candida albicans

Itraconazole (ITC), a well-known fungistatic agent, has potent fungicidal activity against Candida albicans. However, its mechanism of fungicidal activity has not been elucidated yet, and we aimed to identify the mechanism of ITC against C. albicans. ITC caused cell shrinkage via potassium leakage through the ion channel. Since shrunken cells could indicate apoptosis, we investigated apoptotic features. Annexin V-FITC and TUNEL assays indicated that fungicidal activity of ITC was involved in apoptosis. Subsequently, we confirmed an intracellular factor that could cause apoptosis. ITC treatment caused reactive oxygen species (ROS) accumulation. To confirm whether ROS is related with ITC-triggered cell death, cell viability was examined using the ROS scavenger N-acetylcysteine (NAC). NAC pretreatment recovered ITC-induced cell death, indicating that antifungal activity of ITC is associated with ROS, which is also confirmed by impaired glutathione-related antioxidant system and oxidized intracellular lipids. Moreover, ITC-induced mitochondrial dysfunction, in turn, triggered cytochrome c release and metacaspase activation, leading to apoptosis. Unlike the only ITC-treatment group, cells with NAC pretreatment did not show significant damage to mitochondria, and attenuated apoptotic features. Therefore, our results suggest that ITC induces apoptosis as fungicidal mechanism, and intracellular ROS is major factor to trigger the apoptosis by ITC in C. albicans.

Photo-based PDT/PTT dual model killing and imaging of cancer cells using phycocyanin-polypyrrole nanoparticles

Photodynamic therapy (PDT) and photothermal therapy (PTT) using nanoparticles have gained significant attention for its therapeutic effect for cancer treatment. In the present study, we fabricated polypyrrole nanoparticles by employing bovine serum albumin-phycocyanin complex and the formulated particles were stable in various physiological solutions like water, phosphate buffered saline and culture media. The formulated nanoparticles did not cause any noticeable toxicity to MDA-MB-231 and HEK-293 cells. The obtained nanoparticles effectively killed MDA-MB-231 cells in a dual way upon laser illumination, one is through phycocyanin propagated reactive oxygen species (PDT) upon laser illumination and in another way it eradicated the treated cells by converting optical energy into heat energy (PTT). Additionally, the nanoparticles generated good amplitude of ultrasound signals under photoacoustic imaging (PAT) system that facilitates imaging of treated cells. In conclusion, the fabricated particles could be used as a multimodal therapeutic agent for treatment of cancer in the biomedical field.

Hexavalent chromium induced oxidative stress and apoptosis in Pycnoporus sanguineus

White rot fungi have been proved to be a promising option for the removal of heavy metals, understanding their toxic response to heavy metals is conducive to developing and popularizing fungi-based remediation technologies so as to lessen the hazard of heavy metals. In this study, Cr(VI)-induced oxidative stress and apoptosis in Pycnoporus sanguineus, a species of white rot fungi were investigated. The results suggested that high level of Cr(VI) promoted the formation of ROS, including H₂O₂, O₂^•- and ·OH. With the increment of Cr(VI) concentration, the SOD and CAT activity along with GSH content increased within the first 24 h, but decreased afterward, companied with a significant enhancement of MDA content. Cr(VI)-induced oxidative damage further caused and aggravated apoptosis in P. sanguineus, especially at Cr(VI) concentrations above 20 mg/L. Cr(VI)-induced apoptosis was involved with mitochondrial dysfunction including mitochondrial depolarization, the enhancement of mitochondrial permeability and release of cytochrome c. The early and late apoptosis hallmarks, such as metacaspase activation, phosphatidylserine (PS) externalization, DNA fragmentation and the nuclear condensation and fragmentation were observed. Moreover, we also found disturbances of ion homeostasis, which was featured by K⁺ effluxes and overload of cytoplasmic and mitochondrial Ca²⁺.Based on these results, we suggest that Cr(VI) induced oxidative stress and apoptosis in white rot fungi, P. sanguineus.

Plants' Natural Products as Alternative Promising Anti-Candida Drugs

Candida is a serious life-threatening pathogen, particularly with immunocompromised patients. Candida infections are considered as a major cause of morbidity and mortality in a broad range of immunocompromised patients. Candida infections are common in hospitalized patients and elderly people. The difficulty to eradicate Candida infections is owing to its unique switch between yeast and hyphae forms and more likely to biofilm formations that render resistance to antifungal therapy. Plants are known sources of natural medicines. Several plants show significant anti-Candida activities and some of them have lower minimum inhibitory concentration, making them promising candidates for anti-Candida therapy. However, none of these plant products is marketed for anti-Candida therapy because of lack of sufficient information about their efficacy, toxicity, and kinetics. This review revises major plants that have been tested for anti-Candida activities with recommendations for further use of some of these plants for more investigation and in vivo testing including the use of nanostructure lipid system.

Effect of different levels of intermittent hypoxia on autophagy of hippocampal neurons

PURPOSE

The current study was carried out to assess the effects of different levels of intermittent hypoxia (IH) on autophagy in hippocampal neurons, and explore the extent, frequency and duration of IH for researching on autophagy in hippocampal neurons.

METHODS

Hippocampal neurons were exposed to different levels of IH. To analyze the oxygen level of neuronal exposure environment, we detected the oxygen concentration in the chamber by O₂ analyzer, and monitored the oxygen partial pressure (PO₂), carbon dioxide partial pressure (PCO₂), and pH in the culture media by blood gas analyzer. After 4-, 8-, and 12-h IH, the morphology and quantity of neurons, as well as the expression of light chain 3 (LC3)-II positive dots were observed by immunofluorescence. The expression of apoptosis marker protein cleaved caspase-3 and autophagy marker protein LC3 were examined by western blotting.

RESULTS

The oxygen level in the chamber and the neuronal culture media both reached to the values set previously in three models. The level of cleaved caspase-3 and LC3 had no significant changes in IH-1 group. The morphology and quantity had no significant changes, while the levels of cleaved caspase-3 and LC3 were both increased in IH-2 group. The quantity of neurons was reduced significantly, and the chromatin condensed and nuclei fragmented in IH-3 group.

CONCLUSIONS

The effects of varying degrees of IH on autophagy in hippocampal neurons are different. The IH model, hypoxia phase (1.5% O₂, 5% CO₂, and balance N₂) for 5 min and reoxygenation phase (21% O₂, 5% CO₂, and balance N₂) for 10 min, may be the best condition for researching on autophagy in hippocampal neurons.

An Antifungal Mechanism of Protolichesterinic Acid from the Lichen Usnea albopunctata Lies in the Accumulation of Intracellular ROS and Mitochondria-Mediated Cell Death Due to Apoptosis in Candida tropicalis

Candida species causes superficial and life-threatening systemic infections and are difficult to treat due to the resistance of these organism to various clinically used drugs. Protolichesterinic acid is a well-known lichen compound. Although the antibacterial activity of protolichesterinic acid has been reported earlier, the antifungal property and its mechanism of action are still largely unidentified. The goal of the present investigation is to explore the anticandidal activity and mechanism of action of protolichesterinic acid, especially against Candida tropicalis. The Minimum Inhibitory Concentration (MIC) value was established through microdilution techniques against four Candida species and out of four species tested, C. tropicalis showed a significant effect (MIC: 2 μg/ml). In the morphological interference assay, we observed the enhanced inhibition of hyphae when the cells were treated with protolichesterinic acid. Time-kill assay demonstrated that the maximum rate of killing was recorded between 2 and 6 h. C. tropicalis exposed to protolichesterinic acid exhibited an increased ROS production, which is one of the key factors of fungal death. The rise in ROS was due to the dysfunction of mitochondria caused by protolichesterinic acid. We confirmed that protolichesterinic acid-induced dysfunction of mitochondria in C. tropicalis. The damage of cell membrane due to protolichesterinic acid treatment was confirmed by the influx of propidium iodide and was further confirmed by the release of potassium ions. The treatment of protolichesterinic acid also triggered calcium ion signaling. Moreover, it commenced apoptosis which is clearly evidenced by Annexin V and propidium iodide staining. Interestingly protolichesterinic acid recorded excellent immunomodulatory property when tested against lymphocytes. Finally protolichesterinic acid showed low toxicity toward a normal human cell line Foreskin (FS) normal fibroblast. In in vivo test, protolichesterinic acid significantly enhanced the survival of C. tropicalis infected Caenorhabditis elegans. This investigation proposes that the protolichesterinic acid induces apoptosis in C. tropicalis via the enhanced accumulation of intracellular ROS and mitochondrial damage, which leads fungal cell death via apoptosis. Our work revealed a new key aspect of mechanisms of action of protolichesterinic acid in Candida species. This article is the first study on the antifungal and mechanism of action of protolichesterinic acid in Candida species.