pradimicin-a and Mycoses

Due to the limit of available treatments and the emergence of drug resistance in the clinic, invasive fungal infections are an intractable problem with high morbidity and mortality. The cell wall, as a fungi-specific structure, is an appealing target for the discovery and development of novel and low-toxic antifungal agents. In an attempt to accelerate the discovery of novel cell wall targeted drugs, this Perspective will provide a comprehensive review of the progress made to date on the development of fungal cell wall inhibitors. Specifically, this review will focus on the targets, discovery process, chemical structures, antifungal activities, and structure-activity relationships. Although two types of cell wall antifungal agents are clinically available or in clinical trials, it is still a long way for the other cell wall targeted inhibitors to be translated into clinical applications. Future efforts should be focused on the identification of inhibitors against novel conserved cell wall targets.

Topics: Antifungal Agents; Cell Wall; Drug Discovery; Fungi; GPI-Linked Proteins; Humans; Mannans; Mycoses; Triterpenes

Three N,N-dimethyl pradimicins were synthesized by reductive alkylation of pradimicins A, E and FA-2 and evaluated for antifungal activity, water solubility and acute toxicity in mice. They showed in vitro antifungal activity superior to pradimicin A. N,N-Dimethylpradimicins E and FA-2 showed great improvement in water solubility and animal tolerance. N,N-Dimethylpradimicin FA-2 was effective in 3 experimental in vivo fungal infection models.

Topics: Alkylation; Animals; Anthracyclines; Antibiotics, Antineoplastic; Antifungal Agents; Candida; Disease Models, Animal; Drug Tolerance; Fungi; Male; Mice; Mice, Inbred ICR; Molecular Structure; Mycoses; Oxidation-Reduction; Solubility

Pradimicins A, B and C specify novel antibiotics produced by Actinomadura hibisca No. P157-2 (ATCC 53557) possessing potent and broad antifungal activity in vivo. They showed moderate in vitro antifungal activity against a wide variety of fungi and yeasts including clinically important pathogens, and were highly effective in systemic infection with Candida albicans in mice after iv and im administrations. Pradimicin A showed in vivo therapeutic activity against C. albicans, Cryptococcus neoformans and Aspergillus fumigatus in both normal and immunocompromized mice. 5-Fluorocytosine- and azole-resistant C. albicans strains were susceptible to pradimicin A. This antibiotic also demonstrated therapeutic efficacy against lung candidiasis and aspergillosis, vaginal candidiasis and skin Trichophyton mentagrophytes infection in mice with iv or topical treatment. The LD50 values after a single iv or im administration were 120 mg/kg and more than 400 mg/kg, respectively. Against various cultured mammalian cells, pradimicin A was noncytotoxic at 100 or 500 micrograms/ml, and showed potent anti-influenza virus activity with an IC50 value of 6.8 micrograms/ml.

Topics: Animals; Anthracyclines; Antibiotics, Antineoplastic; Antifungal Agents; Antiviral Agents; Cells, Cultured; Dermatomycoses; Female; Fungi; Lung Diseases, Fungal; Male; Mice; Mice, Inbred ICR; Mycoses; Orthomyxoviridae; Simplexvirus; Vaginitis; Viral Plaque Assay