Antifungal antibiotics

The search for new drugs against fungal infections is a major challenge to current research in mycotic diseases. The present article reviews the current types of antifungal infections, the current scenario of antifungal antibiotics, and the need and approaches to search for newer antifungal antibiotics and antifungal drug targets.

Mathemycin B, a new antifungal macrolactone from actinomycete species HIL Y-8620959

A new macrocyclic lactone antibiotic mathemycin B (1) was isolated from the fermentation broth of an Actinomycete sp. culture Y-8620959. The structure of 1 was elucidated by high-resolution MS and interpretation of 2D NMR results. Mathemycin B is active against a variety of phytopathogenic organisms.

Arthrichitin. A New Cell Wall Active Metabolite from Arthrinium phaeospermum

Arthrichitin (1), C(33)H(46)N(4)O(9), is a new cell wall active depsipeptide isolated from the fermentation broth of Arthrinium phaeospermum (HIL Y-903022). Its structure was elucidated on the basis of spectroscopic and chemical degradation studies. Arthrichitin consists of serine, beta-keto tryptophan, glutamic acid, and 2,4-dimethyl-3-hydroxydodecanoic acid units.

Balhimycin, a new glycopeptide antibiotic produced by Amycolatopsis sp. Y-86,21022. Taxonomy, production, isolation and biological activity

A new glycopeptide antibiotic, balhimycin, has been isolated from the fermentation broth of a Amycolatopsis sp. Y-86,21022. Balhimycin belongs to the vancomycin class of glycopeptides and contains a dehydrovancosamine sugar. The biological activity of balhimycin has been compared extensively with that of vancomycin against methicillin resistant staphylococci and also against anaerobes. Balhimycin is marginally superior to vancomycin in its in vitro activity against anaerobes and in its bactericidal properties.

Aranorosinol A and aranorosinol B, two new metabolites from Pseudoarachniotus roseus: production, isolation, structure elucidation and biological properties

Two new secondary metabolites, aranorosinol A (1) and aranorosinol B (2), were isolated from a strain of Pseudoarachniotus roseus. Their structures were elucidated on the basis of their spectral properties and chemical transformations and were found to be similar to aranorosin (3) isolated from the same strain.

Mersacidin, a new antibiotic from Bacillus. In vitro and in vivo antibacterial activity

Mersacidin is a new peptide antibiotic of the proposed lantibiotic family. It is active in vitro and in vivo against Gram-positive bacteria including the methicillin-resistant Staphylococci. Its in vitro activity is less than those of vancomycin and erythromycin but it shows much higher activity in the in vivo system than can be expected from the in vitro testing results. A water soluble potassium salt has been prepared which has an activity profile similar to that of mersacidin, but has better in vivo activity against Streptococcus pyogenes than the parent compound.

Mersacidin, a new antibiotic from Bacillus. Fermentation, isolation, purification and chemical characterization

Mersacidin (1) is a new peptide antibiotic containing beta-methyllanthionine. It is classified as a member of the proposed lantibiotic group of antibiotics, and is produced by a species of Bacillus. Mersacidin has a molecular weight of 1,824 (C80H120N20O21S4). The antibiotic is active against Gram-positive organisms including methicillin-resistant Staphylococcus aureus, but has no activity against Gram-negative bacteria or fungi.

Deoxymulundocandin--a new echinocandin type antifungal antibiotic

A new echinocandin type antifungal antibiotic, deoxymulundocandin, C48H77N7O15, was isolated from the culture filtrate and mycelia of a fungal culture, Aspergillus sydowii (Bainier and Sartory) Thom and Church var. nov. mulundensis Roy (Culture No. Y-30462). The structure was established by comparative GC-MS analyses of the derivatized acid hydrolysates of deoxymulundocandin and mulundocandin as well as by the high field NMR experiments (COSY, NOESY and DEPT).

Alisamycin, a new antibiotic of the manumycin group. I. Taxonomy, production, isolation and biological activity

Alisamycin is a new member of the manumycin group of antibiotics produced by Streptomyces sp. HIL Y-88,31582, which taxonomically appears to be Streptomyces actuosus. Alisamycin is active against Gram-positive bacteria and fungi, and has a weak antitumour activity.

Butalactin, a new butanolide antibiotic. Taxonomy, fermentation, isolation and biological activity

Butalactin, [2-(4',5'-epoxy-hex-2'(E)-en)oyl-2-hydroxy-3-hydroxymethyl-2, 3-(Z)-butanolide] is a new antibiotic produced by Streptomyces sp. HIL Y-86,36923. Taxonomically, the producing organism most closely resembles Streptomyces corchorusii. The strain also produces cineromycin B. Though butalactin is structurally related to 'signal molecules' such as A-factor, the anthracycline inducing factors and the virginiae butanolides, it does not show inducing activity for antibiotic production or aerial mycelium formation in the indicator strain. Butalactin possesses a weak antibiotic activity against Gram-positive and Gram-negative bacteria.

Aranorosin, a novel antibiotic from Pseudoarachniotus roseus. II. Structure elucidation

Aranorosin, a new antifungal antibiotic, has been isolated from the culture filtrate and mycelium of a strain of Pseudoarachniotus roseus Kuehn. The antibiotic, C23H33NO6, contains a novel 1-oxaspiro[4,5]decane ring system. The structure (I) has been elucidated on the basis of spectroscopic and chemical analysis.

Aranorosin, a novel antibiotic from Pseudoarachniotus roseus. I. Taxonomy, fermentation, isolation, chemical and biological properties

A novel antibiotic, aranorosin, was isolated from the fermentation broth of a new fungal isolate identified as Pseudoarachniotus roseus. The antibiotic showed a wide spectrum of activity.

Swalpamycin, a new macrolide antibiotic. I. Taxonomy of the producing organism, fermentation, isolation and biological activity

A new macrolide antibiotic, swalpamycin, has been isolated from the culture broth of Streptomyces sp. Y-84,30967. Taxonomically the producing organism most closely resembles Streptomyces anandii and has therefore been named S. anandii subsp. swalpus. Swalpamycin is a neutral 16-membered macrolide active against Gram-positive bacteria including erythromycin-resistant strains.

Swalpamycin, a new macrolide antibiotic. II. Structure elucidation

A new antibiotic swalpamycin (1) has been isolated from the culture broth of Streptomyces sp. Y-84,30967. The antibiotic has the molecular formula of C37H56O14 and belongs to the class of 16-membered neutral macrolide antibiotics. Its structure has been elucidated by an analysis of its spectral properties. It contains a novel aglycone herein called swalpanolide.

Mulundocandin, a new lipopeptide antibiotic. II. Structure elucidation

The structure of a new antifungal antibiotic, mulundocandin, C48H77N7O16, was elucidated by high field NMR experiments e.g., homo- and heteronuclear correlation spectra, distortionless enhancement by polarization transfer (DEPT) spectra as well as nuclear Overhauser effect. The compound is a lipopeptide antibiotic belonging to the echinocandin class.

Mulundocandin, a new lipopeptide antibiotic. I. Taxonomy, fermentation, isolation and characterization

Mulundocandin, a new lipopeptide antibiotic, was isolated from the culture broth of a strain of Aspergillus sydowi No. Y-30462. The antibiotic, obtained as a colorless amorphous powder having the molecular formula C48H77N7O16, is an antifungal antibiotic active against yeasts and filamentous fungi.

Antiamoebic activity of chonemorphine, a steroidal alkaloid, in experimental models

Chonemorphine, a steroidal alkaloid isolated from Chonemorpha fragrans Moon (Apocyanaceae) was identified as an antimoebic principle during the course of a screening programme for novel antiparasitic agents from plant sources. At a dosage of 100 mg/kg x 4 chonemorphine led to a 100% cure of experimental hepatic infection in golden hamsters and cleared 90% of the intestinal infection in weanling Wistar rats at 200 mg/kg (x4) dosages. The discovery of chonemorphine as an antiamoebic agent is an addition to the few known plant amoebicides such as emetine and conessine.

Improved screening for beta-lactam antibiotics. A sensitive, high-throughput assay using DD-carboxypeptidase and a novel chromophore-labeled substrate

The very sensitive and specific method for the detection of beta-lactam antibiotics using DD-carboxypeptidase (DDCase) from Actinomadura strain R39 has been improved to meet the requirements of a high-throughput beta-lactam screening from culture broths of microorganisms. The method is based on a novel chromophor-labeled substrate N alpha-acetyl-N epsilon-4-(7-nitrobenzofurazanyl)-L-lysyl-D-al anyl-D-alanine (ANLA2) which is converted by DDCase into ANLA1 with only one D-alanine residue left. Both compounds are intensely yellow as well as highly fluorescent and can be separated by thin-layer chromatography. This allows easy determination of residual DDCase activity after reaction with beta-lactams by simple visual inspection of chromatograms. Also, many assays can be run at a time without sophisticated instrumentation. Details of the method as well as some results of a beta-lactam screening performed with this type of assay are described.

Stereochemistry of the epoxydon group antibiotic G7063-2 isolated from a Streptomyces species HPL Y-25711

The absolute configuration of the ring system of the antibiotic G7063-2 has been established as being the same as that reported for terreic acid, based on circular dichroism data. During structure elucidation experiments, reaction with ethereal diazomethane gave an adduct whose structure is proposed.

Caerulomycin, an antifungal antibiotic with marked in vitro and in vivo activity against Entamoeba histolytica

The anti-amoebic action of the bipyridyl antibiotic caerulomycin was assessed in vitro and in vivo using various strains of Entamoeba histolytica from polyxenic, axenic and monoxenic cultures. Minimum inhibition concentrations of caerulomycin (metronidazole) were 7.5 (5), 15.6(1.95) and 60 (2.5) micrograms/ml against polyxenic, axenic and monoxenic cultures of E. histolytica, respectively. The ED50 values ascertained in golden hamsters (extraintestinal amoebiasis) and rats (intestinal amoebiasis) after the oral route were 136 and 199 mg/kg (X4), respectively. Metronidazole proved to be approximately four times more active against tissue forms of E. histolytica than caerulomycin [ED50 of metronidazole: less than 40 mg/kg (X4)]. The antibiotic was slightly superior to metronidazole in its action on lumen forms of E. histolytica [ED50 of metronidazole: 233 mg/kg (X4)]. The antibiotic was in some cases toxic to hamsters and rats within the therapeutic range.

Countercurrent distribution studies on hamycin

Hamycin, a polyene antifungal antibiotic, was isolated by use of countercurrent distribution. A pattern was obtained by plotting the absorption at 383 mmu of the contents of the various tubes against the tube numbers. The results indicated that the antibiotic contained three fractions, a major fraction (peak 2) comprising 48% of the total activity and two minor fractions (peak 1 and peak 3) comprising 3.62 and 11.32%, respectively, of the total activity. The solid material was isolated by pooling the contents of the tubes containing the major fraction, concentrating this in vacuo, and cooling. The antibiotic activities of the three peaks were evaluated by use of a cup-plate assay method with Paecilomyces varioti as test organism. All three components showed antibiotic activity; however, the preparation obtained from the major fraction showed approximately a 7-fold increase in antibiotic activity, a doubling of the E(1cm) (1%) value at 383 mmu, and approximately a 2.5-fold decrease in the amino acid content in comparison with the starting material. There was an apparent correlation obtained by plotting the curves of the absorption at 383 mmu of the different tubes comprising the major fraction and their biological activities.