Current Pharmaceutical Design - Volume 26, Issue 14, 2020

Fungal diseases are life-threatening to human health and responsible for millions of deaths around the world. Fungal pathogens lead to a high number of morbidity and mortality. Current antifungal treatment comprises drugs, such as azoles, echinocandins, and polyenes and the cure is not guaranteed. In addition, such drugs are related to severe side effects and the treatment lasts for an extended period. Thus, setting new routes for the discovery of effective and safe antifungal drugs should be a priority within the health care system. The discovery of alternative and efficient antifungal drugs showing fewer side effects is time-consuming and remains a challenge. Natural products can be a source of antifungals and used in combinatorial therapy. The most important natural products are antifungal peptides, antifungal lectins, antifungal plants, and fungi secondary metabolites. Several proteins, enzymes, and metabolic pathways could be targets for the discovery of efficient inhibitor compounds and recently, heat shock proteins, calcineurin, salinomycin, the trehalose biosynthetic pathway, and the glyoxylate cycle have been investigated in several fungal species. HSP protein inhibitors and echinocandins have been shown to have a fungicidal effect against azole-resistant fungi strains. Transcriptomic and proteomic approaches have advanced antifungal drug discovery and pointed to new important specific-pathogen targets. Certain enzymes, such as those from the glyoxylate cycle, have been a target of antifungal compounds in several fungi species. Natural and synthetic compounds inhibited the activity of such enzymes and reduced the ability of fungal cells to transit from mycelium to yeast, proving to be promisor antifungal agents. Finally, computational biology has developed effective approaches, setting new routes for early antifungal drug discovery since normal approaches take several years from discovery to clinical use. Thus, the development of new antifungal strategies might reduce the therapeutic time and increase the quality of life of patients.

In the Fall of 1999, we presented at medical “Grand Rounds” to a number of Infectious Diseases physicians at Vancouver General Hospital about the co-administration of several antifungal compounds in the treatment of blood-borne fungal infections to patients who were immunocompromised (i.e. cancer patients, patients waiting organ transplantation, HIV/AIDs patients, etc.). During the presentation, a physician from the back of the room called out “can you develop an oral formulation of amphotericin B which could be effective and not have the side-effects associated with the parenteral formulations of the drug”. The physician stated that an oral formulation would be a big step forward, improving patient compliance, helping in pre-treatment without admitting patients to the hospital prior to organ transplantation and it would be cost-effective. Initially, I responded to the physician, that it would not be possible to develop an oral amphotericin B formulation that could be absorbed from the gastrointestinal (GI) tract in a high enough concentration to be effective in treating blood-borne fungal infections and yet remains non-toxic due to the physical chemical properties of the drug. However, as I travelled back to my lab from the meeting, it struck me that our understanding of how lipids had been processed and orally absorbed from the GI had advanced to the point the maybe incorporating amphotericin B into such lipids might work. Within several years, our laboratory was able to develop a novel oral amphotericin B formulation that was indeed effective in treating systemic fungal infections without the side-effects associated with the drug in a variety of fungal animal models.

Background: Onychomycosis is a chronic nail infection caused by fungi frequently resistant to antifungal treatments. Recalcitrance in nail infections is a result of reduced antifungal penetration due to biofilm formation, combined with poor patient compliance with the treatment, which can be as long as 18 months. Objective: Metal-drug complexation is a widely used strategy to increase drug efficacy. Therefore, the aim of this work was to evaluate the antifungal and anti-biofilm activity of several metal-azole complexes against Candida albicans and Candida glabrata. Methods: Susceptibility assays and scanning electron microscopy were performed to determine the anti-biofilm activity of eight metal-azole complexes in vitro and ex-vivo, using human nail fragments. Results: In vitro susceptibility assays showed that complexation of both Au(I) and Zn(II) to clotrimazole and ketoconazole improved the anti-biofilm activity compared to the azole alone. Using an ex-vivo model of biofilm formation on fragments of human nails, we also demonstrate the improved efficacy of metal-azole complexes against biofilms of C. albicans and C. glabrata that resembles the onychomycosis structure. Noteworthy, biofilms of C. glabrata were more susceptible to the optimized complexes than those of C. albicans. Conclusion: In conclusion, metal-azole complexes used in this work show promising anti-biofilm activity and further clinical studies should confirm its potential for the treatment of Candida-associated onychomycosis.

Background: Fusarium solani f. sp. piperis is a phytopathogen that causes one of the most destructive diseases in black pepper crops, resulting in significant economic and crop production losses. Consequently, the control of this fungal disease is a matter of current and relevant interest in agriculture. Objective: The objective was to synthesize eugenol derivatives with antifungal activity. Methods: In this study, using bimolecular nucleophilic substitution and click chemistry approaches, four new and three known eugenol derivatives were obtained. The eugenol derivatives were characterized and their antifungal and cytotoxic effects were evaluated. Results: Eugenol derivative 4 (2-(4-allyl-2-methoxyphenoxy)-3-chloronaphthalene-1,4-dione) was the most active against F. solani f. sp. piperis and showed acceptable cytotoxicity. Compound 4 was two-fold more effective than tebuconazole in an antifungal assay and presented similar cytotoxicity in macrophages. The in silico study of β-glucosidase suggests a potential interaction of 4 with amino acid residues by a cation-π interaction with residue Arg177 followed by a hydrogen bond with Glu596, indicating an important role in the interactions with 4, justifying the antifungal action of this compound. In addition, the cytotoxicity after metabolism was evaluated as a mimic assay with the S9 fraction in HepG2 cells. Compound 4 demonstrated maintenance of cytotoxicity, showing IC50 values of 11.18 ± 0.5 and 9.04 ± 0.2 μg mL-1 without and with the S9 fraction, respectively. In contrast, eugenol (257.9 ± 0.4 and 133.5 ± 0.8 μg mL-1), tebuconazole (34.94 ± 0.2 and 26.76 ± 0.17 μg mL-1) and especially carbendazim (251.0 ± 0.30 and 34.7 ± 0.10 μg mL-1) showed greater cytotoxicity after hepatic biotransformation. Conclusion: The results suggest that 4 is a potential candidate for use in the design of new and effective compounds that could control this pathogen.

Background: Topical therapy is preferred for the management of ocular fungal infections due to its superiorities which include overcoming potential systemic side effects risk of drugs, and targeting of drugs to the site of disease. However, the optimization of effective ocular formulations has always been a major challenge due to restrictions of ocular barriers and physiological conditions. Posaconazole, an antifungal and highly lipophilic agent with broad-spectrum, has been used topically as off-label in the treatment of ocular fungal infections due to its highly lipophilic character. Micellar carriers have the potential to improve the solubility of lipophilic drugs and, overcome ocular barriers. Objective: In the current study, it was aimed optimization of posaconazole loaded micellar formulations to improve aqueous solubility of posaconazole and to characterize the formulations and to investigate the physical stability of these formulations at room temperature (25°C, 60% RH), and accelerated stability (40°C, 75% RH) conditions. Methods: Micelles were prepared using a thin-film hydration method. Pre-formulation studies were firstly performed to optimize polymer/surfactant type and to determine their concentration in the formulations. Then, particle size, size distribution, and zeta potential of the micellar formulations were measured by ZetaSizer Nano-ZS. The drug encapsulation efficiency of the micelles was quantified by HPLC. The morphology of the micelles was depicted by AFM. The stability of optimized micelles was evaluated in terms of particle size, size distribution, zeta potential, drug amount and pH for 180 days. In vitro release studies were performed using Franz diffusion cells. Results: Pre-formulation studies indicated that single D-α-tocopheryl polyethylene glycol succinate (TPGS), a combination of it and Pluronic F127/Pluronic F68 are capable of formation of posaconazole loaded micelles at specific concentrations. Optimized micelles with high encapsulation efficiency were less than 20 nm, approximately neutral, stable, and in aspherical shape. Additionally, in vitro release data showed that the release of posaconazole from the micelles was higher than that of suspension. Conclusion: The results revealed that the optimized micellar formulation of posaconazole offers a potential approach for topical ocular administration.

Background: Vaginal infections caused by non-albicans species have become common in women of all age groups. The resistance of species such as Candida parapsilosis to the various antifungal agents is a risk factor attributed to these types of infections, which instigates the search for new sources of active compounds in vulvovaginal candidiasis (VCC) therapy. Objective: This study evaluated the antifungal activity of Syngonanthus nitens Bong. (Ruhland) derivatives and employed a lipid nanoemulsion as a delivery system.' Methods: In this study, a lipid nanoemulsion was employed as a delivery system composed of Cholesterol (10%), soybean phosphatidylcholine: Brij 58 (1: 2) and PBS (pH 7.4) with the addition of 0.5% of a chitosan dispersion (80%), and evaluated the antifungal activity of S. nitens Bong. (Ruhland) derivatives against planktonic cells and biofilms of Candida parapsilosis. By a biomonitoring fractionation, the crude extract (EXT) and one fraction (F2) were selected and incorporated into a lipid nanoemulsion (NL) composed of cholesterol (10%), a 1:2 mixture of soybean phosphatidylcholine:polyoxyethylene -20- cetyl ether (10%), and phosphate buffer solution (pH 7.4) with a 0.5% chitosan dispersion (80%). The NL presented a diameter size between 50-200 nm, pseudoplastic behavior, and positive charge. The EXT and five fractions were active against planktonic cells. Results and Discussion: The incorporation of EXT and F2 into the NL increased antifungal activity and enhanced the anti-biofilm potential. This study classified the use of an NL as an important tool for the administration of S. nitens derivatives in cases of infections caused by this C. parapsisilosis. Conclusion: This work concluded that S. nitens derivatives were important sources of active molecules against C. parapsilosis and the use of a lipid nanoemulsion was an important tool to promote more effective F2 release and to improve the antifungal activity aiming the control of C. parapsilosis infections.

In recent years, the development of new pharmaceutical formulations for the treatment of sporotrichosis has become a relevant research field. In this work, we aimed to develop an emulgel containing itraconazole and clotrimazole to ensure therapeutic effectiveness against Sporothrix brasiliensis. The topical use of a formulation that combines both drugs represents an interesting option for the complementary treatment of sporotrichosis. The emulgel formulation was prepared and evaluated for its zeta potential, viscosity, in vitro antifungal activity and stability at different storage conditions. The results showed that the newly developed emulgel displayed promising physicochemical characteristics, as well as a good in vitro inhibitory activity against S. brasiliensis yeasts. The results obtained in this work suggest that the emulgel containing itraconazole and clotrimazole might highly be efficient and a complementary therapy to oral administration in the treatment of sporotrichosis.

Background: Advanced heart failure (HF) is a progressive disease with high mortality and limited medical therapeutic options. Long-term mechanical circulatory support and heart transplantation remain goldstandard treatments for these patients; however, access to these therapies is limited by the advanced age and multiple comorbidities of affected patients, as well as by the limited number of organs available. Methods: Traditional and new drugs available for the treatment of advanced HF have been researched. Results: To date, the cornerstone for the treatment of patients with advanced HF remains water restriction, intravenous loop diuretic therapy and inotropic support. However, many patients with advanced HF experience loop diuretics resistance and alternative therapeutic strategies to overcome this problem have been developed, including sequential nephron blockade or use of the hypertonic saline solution in combination with high-doses of furosemide. As classic inotropes augment myocardial oxygen consumption, new promising drugs have been introduced, including levosimendan, istaroxime and omecamtiv mecarbil. However, pharmacological agents still remain mainly short-term or palliative options in patients with acute decompensation or excluded from mechanical therapy. Conclusion: Traditional drugs, especially when administered in combination, and new medicaments represent important therapeutic options in advanced HF. However, their impact on prognosis remains unclear. Large trials are necessary to clarify their therapeutic potential and prognostic role in these fragile patients.

Cupressus sempervirens, Platycladus orientalis, Juniperus communis, J. excelsa, J. foetidissima, J. polycarpos var. turcomanica, J. sabina, and Taxus baccata are conifers in Iran. These plants have a long reputation in different systems of traditional medicines for a variety of diseases. This review aims to provide comprehensive and up-to-date information about the ethnopharmacological uses, chemical constituents, and pharmacology of these conifers. Furthermore this study comprises a bibliographical survey of major Islamic Traditional Medicine (ITM) books regarding different medical aspects of these species. A literature search was conducted on the applications of these conifers both in traditional and modern medicines by referencing traditional textbooks and scientific databases. Ethnobotanical literature review indicates that various parts of the plants including cones, berries, leaves, bark, wood, and resin have been used for a broad spectrum of applications. In Iran, C. sempervirens, J. sabina, J. communis, and T. baccata have been used traditionally for the treatment of urinary, digestive, nervous, respiratory, and integumentary systems-related problems. The phytochemical constituents of these plants can be divided into two main categories: volatile and non-volatile components, all dominated by terpenes. Considering the pharmacological and clinical evidence, while some of the traditional applications of these plants are supported by modern medicine, implying the value of the traditional and folklore knowledge for finding new lead compounds in drug discovery, some have remained unexamined showing the need for much more studies in this regard.

Background: Ghrelin (GHRL) is a polypeptide that can specifically bind to the growth hormone secretagogue receptor (GHSR). The expression of GHSR is significantly different in normal and prostate cancer (PC) tissues in humans. It is important to find an effective diagnostic method for the diagnosis and prognosis of invasive PC/neuroendocrine prostate cancer (NEPC). Methods: GHRL and GHSR mRNA levels were determined by a quantitative real-time polymerase chain reaction in PC tissues. The expression of GHRL and GHSR proteins was assessed by Western blot assay and immunohistochemistry. A GHRL polypeptide probe was synthesized by standard solid-phase polypeptide synthesis, and labeled with Alexa Fluor 660. Confocal microscopy was used to capture fluorescence images. Living imaging analysis showed tumor areas of different invasiveness in mice models. Results: The levels of GHRL and GHSR copy number amplification and mRNA expression were increased in invasive PC/NEPC, and the protein expression levels of GHRL and GHSR were similarly increased in NEPC. The GHRL polypeptide probe could effectively bind to GHSR. In PC3 cells, it was found that the GHRL probe specifically binds to GHSR on the cell membrane and accumulates in the cells through internalization after binding. Live imaging in mice models showed that there were different signal intensities in tumor areas with different invasiveness. Conclusion: GHSR and GHRL might be used in molecular imaging diagnosis for invasive PC/NEPC in the future.

Background/Objective: KRAS-mutant colorectal cancers (CRC) are tumors that are associated with poor prognosis. However, no effective treatments are available to target them. Therefore, we designed and synthesized novel chalcone analogs, small organic molecules, to investigate their effects on KRAS-mutant CRC cells. Methods: Fourteen new chalcone analogs were synthesized, optimized, characterized, and tested against two KRAS-mutant CRC cell lines (HCT-116 and LoVo), one p-53 and BRAF mutant CRC cell line (HT-29) and one normal immortalized colon cells (NCE-1 E6/E7). Effects on cell viability, apoptosis, cell cycle, migration, colony formation, EMT, and angiogenesis were investigated. Results: Compounds 3 and 14 were the most effective. Compound 3 showed potent activity against HCT-116 and LoVo cell lines (GI50 of 6.10 μM and 7.00 μM, respectively). While compound 14 showed GI50 of 8.60 μM and 8.80 μM on HCT-116 and LoVo cell lines, respectively. Both compounds were approximately 2-3 times more selective toward cancer cells rather than normal colon cells. Compound 3 was effective in inducing apoptosis in HCT-116 cells via Bax upregulation and Bcl-2 downregulation. Invasion and metastasis of KRAS-mutant cells were modulated by compounds 3 and 14 through significant inhibition of cell migration and the prevention of colony formation. In addition, they reversed EMT by downregulation of EMT markers (vimentin, fascin, and β- catenin) and upregulation of cell-cell adhesion marker, E-cadherin. Furthermore, compounds 3 and 14 had significantly inhibited angiogenesis in ovo. Conclusion: Compounds 3 and 14 represent potent and selective leads for KRAS-mutant CRC cells, thus, further in vitro and in vivo studies are necessary to confirm their effect on KRAS-mutant CRCs.