Antifungal Agent 4-AN Changes the Genome-Wide Expression Profile, Downregulates Virulence-Associated Genes and Induces Necrosis in Candida albicans Cells.

In the light of the increasing occurrence of antifungal resistance, there is an urgent need to search for new therapeutic strategies to overcome this phenomenon. One of the applied approaches is the synthesis of small-molecule compounds showing antifungal properties. Here we present a continuation of the research on the recently discovered anti-Candida albicans agent 4-AN. Using next generation sequencing and transcriptional analysis, we revealed that the treatment of C. albicans with 4-AN can change the expression profile of a large number of genes. The highest upregulation was observed in the case of genes involved in cell stress, while the highest downregulation was shown for genes coding sugar transporters. Real-time PCR analysis revealed 4-AN mediated reduction of the relative expression of genes engaged in fungal virulence (ALS1, ALS3, BCR1, CPH1, ECE1, EFG1, HWP1, HYR1 and SAP1). The determination of the fractional inhibitory concentration index (FICI) showed that the combination of 4-AN with amphotericin B is synergistic. Finally, flow cytometry analysis revealed that the compound induces mainly necrosis in C. albicans cells.

Biochanin A Inhibits the Growth and Biofilm of Candida Species.

The aim of this study was to investigate the antifungal activity of biochanin A (BCA) against planktonic growth and biofilms of six Candida species, including C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, C. auris, and C. krusei. We applied various assays that determined (a) the antimicrobial effect on growth of Candida species, (b) the effect on formation of hyphae and biofilm, (c) the effect on the expression of genes related to hyphal growth and biofilm formation, (d) the influence on cell wall structure, and (e) the effect on cell membrane integrity and permeability. Moreover, disk diffusion tests were used to investigate the effect of a combination of BCA with fluconazole to assess their possible synergistic effect on drug-resistant C. albicans, C. glabrata, and C. auris. Our results showed that the BCA MIC50 values against Candida species ranged between 125 µg/mL and 500 µg/mL, and the MIC90 values were in a concentration range from 250 µg/mL to 1000 µg/mL. The treatment with BCA inhibited adhesion of cells, cell surface hydrophobicity (CSH), and biofilm formation and reduced hyphal growth in all the analyzed Candida species. Real-time qRT-PCR revealed that BCA down-regulated the expression of biofilm-specific genes in C. albicans. Furthermore, physical destruction of C. albicans cell membranes and cell walls as a result of the treatment with BCA was observed. The combination of BCA and fluconazole did not exert synergistic effects against fluconazole-resistant Candida.

The physiological levels of epigallocatechin gallate (EGCG) enhance the Cd-induced oxidative stress and apoptosis in CHO-K1 cells.

Currently, the increasing pollution of the environment by heavy metals is observed, caused both by natural factors and those related to human activity. They pose a significant threat to human health and life. It is therefore important to find an effective way of protecting organisms from their adverse effects. One potential product showing a protective effect is green tea. It has been shown that EGCG, which is found in large amounts in green tea, has strong antioxidant properties and can therefore protect cells from the adverse effects of heavy metals. Therefore, the aim of the study was to investigate the effect of EGCG on cells exposed to Cd. In the study, CHO-K1 cells (Chinese hamster ovary cell line) were treated for 24 h with Cd (5 and 10 µM) and EGCG (0.5 and 1 µM) together or separately. Cell viability, ATP content, total ROS activity, mitochondrial membrane potential and apoptosis potential were determined. The results showed that, in tested concentrations, EGCG enhanced the negative effect of Cd. Further analyses are needed to determine the exact mechanism of action of EGCG due to the small number of publications on the subject and the differences in the results obtained in the research.

Quinalizarin as a potential antifungal drug for the treatment of Candida albicans fungal infection in cancer patients.

This study aims to analyze the antifungal properties of quinalizarin, a plant-derived compound with proven anticancer effects. Quinalizarin exhibited antifungal activity against opportunistic pathogenic Candida species and Geotrichum capitatum. The treatment with this anthraquinone reduced hyphal growth, inhibited biofilm formation, and damaged mature Candida albicans biofilms. Real-time RT-PCR revealed that quinalizarin downregulated the expression of hyphae-related and biofilm-specific genes. The flow cytometry method used in the study showed that both apoptosis and necrosis were the physiological mechanisms of quinalizarin-induced C. albicans cell death, depending on the dose of the antifungal agent. A further study revealed an increase in the levels of intracellular reactive oxygen species and alterations in mitochondrial membrane potential after treatment with quinalizarin. Finally, quinalizarin was found to have low toxicity in a hemolytic test using human erythrocytes. In conclusion, we have identified quinalizarin as a potential antifungal compound.IMPORTANCEThis article is a study to determine the antifungal activity of quinalizarin (1,2,5,8-tetrahydroxyanthraquinone). Quinalizarin has potential antitumor properties and is effective in different types of tumor cells. The aim of the present study was to prove that quinalizarin can be used simultaneously in the treatment of cancer and in the treatment of intercurrent fungal infections. Quinalizarin was identified as a novel antifungal compound with low toxicity. These results may contribute to the development of a new drug with dual activity in the treatment of cancer-associated candidiasis.

In Vitro and In Vivo Biological Evaluation of Novel 1,4-Naphthoquinone Derivatives as Potential Anticancer Agents.

A novel library of naphthoquinone derivatives (3-5aa) was synthesized and evaluated for their anticancer properties. Specifically, compounds 5i, 5l, 5o, 5q, 5r, 5s, 5t, and 5v demonstrated superior cytotoxic activity against the cancer cell lines that were studied. Notably, compound 5v displayed a greater cytotoxic effect on MCF-7 cells compared to the standard drug doxorubicin. To further investigate the mechanism of cytotoxic effect, additional anticancer studies were conducted with 5v in MCF-7 cells. The findings showed that 5v triggered cytotoxic effects in MCF-7 cells through the initiation of cell cycle arrest at the G1/S phase and necrosis. In vivo ecotoxicity studies indicated that 5v had lower toxicity towards zebrafish larvae (LC50 = 50.15 µM) and had an insignificant impact on cardiac functions. In vivo xenotransplantation of MCF-7 cells in zebrafish larvae demonstrated a significant reduction in tumour volume in the xenograft. Approximately 95% of the zebrafish larvae with 5v xenografts survived after 10 days of the treatment. Finally, a computational modelling study was conducted on four protein receptors, namely ER, EFGR, BRCA1, and VEFGR2. The findings highlight the importance of the aminonaphthoquinone moiety, amide linkage, and propyl thio moiety in enhancing the anticancer properties.

Ceratophyllum demersum the submerged macrophyte from the mining subsidence reservoir Nadrybie Poland as a source of anticancer agents.

Aquatic plants are a rich source of health-beneficial substances. One of such organisms is the submerged macrophyte Ceratophyllum demersum, which has not been sufficiently studied in this aspect so far. In this work, we have studied environmental conditions prevailing in a subsidence mining reservoir in Eastern Poland and shown that C. demersum can be harvested for further analysis even from artificial anthropogenic reservoirs. The phytochemical analysis of C. demersum ethanolic extract using LC-MS revealed high content of phenolic compounds (18.50 mg/g) (mainly flavonoids, 16.09 mg/g), including those that have not yet been identified in this plant, namely isorhamnetin, sakuranetin, taxifolin, and eriodictyol. Such rich flavonoid content is most likely responsible for the anticancer activity of the C. demersum extract, which was targeted especially at neoplastic cells of gastrointestinal tract origin. The flow cytometry analysis of treated cells showed an increased percentage of late apoptotic and necrotic cells. The fish embryo toxicity (FET) test showed safety of the extract towards Danio rerio fish up to the concentration of 225 µg/ml. This study has shown that the submerged macrophyte Ceratophyllum demersum can be taken into consideration as a rich source of a set of anticancer agents with chemopreventive potential.

Inhibitory effect of a combination of baicalein and quercetin flavonoids against Candida albicans strains isolated from the female reproductive system.

Flavonoids are a diverse group of compounds originating from several natural plant sources. Various biological effects of flavonoids have been reported, including antimicrobial and antifungal activities. In this study, we showed the possibility of using commercial flavonoids, i.e. baicalein and quercetin, based on natural equivalents as compounds with antifungal properties against Candida albicans species. The effects of baicalein and/or quercetin were investigated using reference C. albicans strain and 50 clinical strains isolated from vulvovaginal candidiasis (VVC) patients. Baicalein and quercetin MIC values against C. albicans strains ranged between 0.5 and 256 µg/ml. We observed predominantly indifferent, synergistic, or partially synergistic interactions between both flavonoids and between the flavonoids and fluconazole in the treatment of planktonic cells of the C. albicans strains. Treatment with the flavonoid complex inhibited adhesion and aggregation of cells, cell surface hydrophobicity (CSH), flocculation, biofilm formation and reduced hyphal growth. Real-time RT-PCR revealed that baicalein and quercetin in combination down-regulated the expression of biofilm-specific genes. Finally, we observed increase in the cell membrane permeability of C. albicans and its physical destruction as a result of the synergistic activity of baicalein and quercetin. Our research evidences the effectiveness of baicalein and quercetin applied in combination as potential anti-Candida agents.

Production of enriched in B vitamins biomass of Yarrowia lipolytica grown in biofuel waste.

Yarrowia lipolytica as an oleaginous yeast is capable of growing in various non-conventional hydrophobic substrate types, especially industrial wastes. In this study, the content of thiamine (vitamin B1), riboflavin (vitamin B2), pyridoxine (vitamin B6), biotin (vitamin B7) and folic acid (vitamin B9) in the wet biomass of Y. lipolytica strains cultivated in biofuel waste (SK medium), compared to the standard laboratory YPD medium, was assessed. Additionally, the biomass of Y. lipolytica A-101 grown in biofuel waste (SK medium) was dried and examined for B vitamins concentration according to the recommended microbial methods by AOAC Official Methods. The mean values of these vitamins per 100 g of dry weight of Y. lipolytica grown in biofuel waste (SK medium) were as follows: thiamine 1.3 mg/100 g, riboflavin 5.3 mg/100 g, pyridoxine 4.9 mg/100 g, biotin 20.0 µg/100 g, and folic acid 249 µg/100 g. We have demonstrated that the dried biomass is a good source of B vitamins which can be used as nutraceuticals to supplement human diet, especially for people at risk of B vitamin deficiencies in developed countries. Moreover, the biodegradation of biofuel waste by Y. lipolytica is desired for environmental protection.

Silymarin, a Popular Dietary Supplement Shows Anti-Candida Activity.

Silymarin is a complex of plant-derived compounds obtained from the seed shells of the milk thistle (Silybum marianum). It is used in medicine primarily to protect the liver. The mixture contains mainly flavonolignans, with silybin as a paramount bioactive component of the extract. This article presents the potential health benefits for silymarin as an antifungal drug against five references strains: C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei with MIC (minimum inhibitory concentration) values ranging from 30 to 300 µg/mL. Additionally, this study revealed that the compound suppressed the growth of cells of most of the tested clinical Candida albicans strains with MIC values between 30 and 1200 µg/mL. Based on the fractional inhibitory concentration index (FICI), the combination of silymarin with antifungal drugs caspofungin, fluconazole, and amphotericin B did not significantly change the MIC values for the tested Candida strains. Furthermore, no antagonistic reactions were observed in any combination of drugs. In addition, this substance shows anti-virulence properties including the destabilization of mature biofilm and the inhibition of the secretion of hydrolases. qRT-PCR-based experiments demonstrated that the SAP4 gene involved in virulence was downregulated by silymarin. These results indicate completely new advantages of dietary supplementation with this natural plant extract.

Yeast surviving factor Svf1 as a new interacting partner, regulator and in vitro substrate of protein kinase CK2.

Since Svf1 is phosphoprotein, we investigated whether it was a substrate for protein kinase CK2. According to the amino acid sequence Svf1 harbours 20 putative CK2 phosphorylation sites. Here, we have reported cloning, overexpression, purification and characterization of yeast Svf1 as a substrate for three forms of yeast CK2. Svf1 serves as a substrate for both the recombinant CK2alpha (Km 0.35 microM) and CK2alpha' (Km 0.18 microM) as well as CK2 holoenzyme (Km 1.1 microM). Different Km values argue that CK2beta(beta') subunit has an inhibitory effect on the activity of both CK2alpha and CK2alpha' towards surviving factor Svf1. Reconstitution of alpha'2betabeta' isoform of CK2 holoenzyme shows that beta/beta' subunits have regulatory effect depending on the kind of CK2 catalytic subunit. This effect was not observed in the case of alpha2betabeta' isoform, which may be due to interaction between Svf1 and regulatory CK2beta subunit (shown by co-immunoprecipitation experiments). Interactions between CK2 subunits and Svf1 protein may have influence on ATP as well as ATP-competitive inhibitors (TBBt and TBBz) binding. CK2 phosphorylates up to six serine residues in highly acidic peptide K199EVIPESDEEESSADEDDNEDEDEESGDSEEESGSEEESDSEEVEITYED248 of the Svf1 protein in vitro. Presented data may help to elucidate the role of protein kinase CK2 and Svf1 in the regulation of cell survival pathways.