naphthoquinones and Mycoses

During the past two decades, the incidence of invasive fungal infections has been increasing dramatically. Clinical available antifungal agents have several drawbacks such as limited potency and spectrum, drug related toxicity, non-optimal pharmacokinetics, and severe resistance. There is an emergent need to develop new antifungal drugs with novel chemical structures and novel mechanism of action. This review will focus on the most significant achievements in the discovery of antifungal lead structures within last few years. In particular, we pay more attention on the structure-activity relationship of antifungal leads and provide perspectives for future antifungal drug discovery.

Topics: 14-alpha Demethylase Inhibitors; Antifungal Agents; Carbazoles; Drug Discovery; Echinocandins; Enzyme Inhibitors; Glucosyltransferases; Humans; Mycoses; Naphthoquinones; Sterol 14-Demethylase; Structure-Activity Relationship; Triazoles

Topics: 2-Aminopurine; Acyclovir; AIDS-Related Opportunistic Infections; Anti-Infective Agents; Antifungal Agents; Antiprotozoal Agents; Antiretroviral Therapy, Highly Active; Antitubercular Agents; Antiviral Agents; Atovaquone; Azithromycin; Clarithromycin; Cytomegalovirus Infections; Drug Therapy, Combination; Famciclovir; Herpes Simplex; Herpes Zoster; Humans; Mycobacterium avium-intracellulare Infection; Mycoses; Naphthoquinones; Pneumonia, Pneumocystis; Toxoplasmosis; Trimethoprim, Sulfamethoxazole Drug Combination; Tuberculosis, Pulmonary; Valacyclovir; Valine

Mycotoxins are putative virulence factors of fungi that play an important role in the pathogenesis of fungal infections. Mycotoxin production has been used as a diagnostic marker for the early diagnosis of fungal diseases. Using high-performance liquid chromatography, we investigated whether the fungal strains recovered from eye tissue samples obtained from patients with ocular mycoses produced the mycotoxin xanthomegnin. We tested 62 well-characterized strains of fungi, including Aspergillus spp. (n = 14), Exophiala spp. (n = 9), Fusarium spp. (n = 15), and several molds (n = 24). All isolates were identified to the species level using PCR and DNA sequencing of rRNA genes. We detected xanthomegnin activity (0.02 µg/ml) in one of the three Aspergillus flavus strains. However, we were unable to detect xanthomegnin in any of the other 61 fungal strains. Our result suggests that xanthomegnin production was infrequent in fungal strains recovered from patients with ocular mycoses.

Topics: Aspergillus; Exophiala; Eye Infections, Fungal; Fusarium; Humans; Mycoses; Mycotoxins; Naphthoquinones

This study evaluated the antifungal activities of synthetic naphthoquinones against opportunistic and dermatophytic fungi and their preliminary mechanisms of action. The minimum inhibitory concentrations (MICs) of four synthetic naphthoquinones for 89 microorganisms, including opportunistic yeast agents, dermatophytes and opportunistic filamentous fungi, were determined. The compound that exhibited the best activity was assessed for its action against the cell wall (sorbitol test), for interference associated with ergosterol interaction, for osmotic balance (K+ efflux) and for membrane leakage of substances that absorb at the wavelength of 260 nm. All tested naphthoquinones exhibited antifungal activity, and compound IVS320 (3a,10b-dihydro-1H-cyclopenta [b] naphtho [2,3-d] furan-5,10-dione)-dione) demonstrated the lowest MICs across the tested species. The MIC of IVS320 was particularly low for dermatophytes (values ranging from 5-28 μg/mL) and Cryptococcus spp. (3-5 μg/mL). In preliminary mechanism-of-action tests, IVS320 did not alter the fungal cell wall but did cause problems in terms of cell membrane permeability (efflux of K+ and leakage of substances that absorb at 260 nm). This last effect was unrelated to ergosterol interactions with the membrane.

Topics: Antifungal Agents; Cell Membrane Permeability; Fungi; Humans; Microbial Sensitivity Tests; Mycoses; Naphthoquinones

1,4-Naphthoquinones are unique reagents in organic synthesis and have been employed in several well known and recently developed areas of application. Furthermore, these 1,4-naphthoquinones have demonstrated high reactivity in nucleophilic vinylic substitutions, in the preparation of sulfurated, (hetero)cyclic and several other transformations. This study describes the synthesis and biological evaluation of derivatives of monosulfurated naphthalene-1,4-dione (3), 3-chloro-2-ethoxy-naphthalene-1,4-dione (4), disulfurated naphthalene-1,4-dione (5), and symmetrical bis-1,4-naphthoquinones (7, 9) were obtained from the reaction of 2,3-dichloro-naphthaquinone (1) with S-, O-substituted mono-, di-, and tetrathiols, respectively. The structures of the novel products were characterized by spectroscopic methods.

Topics: Anti-Bacterial Agents; Anti-Infective Agents; Antifungal Agents; Bacteria; Bacterial Infections; Fungi; Humans; Microbial Sensitivity Tests; Mycoses; Naphthoquinones; Nitrogen; Sulfur Compounds