Heptaene antibiotics

Therapeutic Function Topical antifungal Chemical Name Heptaene macrolide antibiotic Common Name —... 

Sowinski and coworkers40 reported a structure of vacidin A (63), an aromatic hep-taene macrolide antibiotic. The constitution of vacidin A, a representative of the aromatic heptaene macrolide antibiotics, was established on the basis of 13C and H- H double quantum filtered correlated spectroscopy, rotating frame nuclear Overhauser effect spectroscopy, 7-resolved 11 as well as H-13C correlation NMR spectra. The geometry of the polyene chromophore was determined as 22E, 24E, 26E, 28Z, 30Z, 32E, 34E. 

Polyene antibiotics, such as amphotericin B (II) which contains seven conjugated double bonds (heptaene moiety), are subject to attack by peroxyl radicals, leading to aggregation and loss of activity. ... 

Candicidin production by Streptomyces griseus was inhibited by inorganic phosphate, which suppressed the biosynthesis of p-aminobenzoate, the starter unit for the synthesis of this 38-membered heptaene macrolide antibiotic [95]. P-aminobenzoic acid synthase (PABA synthase) catalyses the conversion of chorismic acid to PABA, which is a precursor to candicidin. 

Amphotericin B is the most important clinically and best defined chemically of the macrolide heptaene antibiotics. A fermentation product of the soil actinomycetes Streptomyces nodosus, amphotericin B binds selectively to ergosterol in the cell membrane of susceptible fungi, inducing changes in permeability that can produce lethal cell injury [50]. 

Exclusion effects are also possible with PRP-1 column depending on the size of the solute molecule. This was evident In the retention behavior of the macrocycllc heptaene antibiotic, amphotericin B, on a PKP-1 column. The reverse-phase fast LC method recently developed In the author s laboratory using a 5-cm long Cig column (3 micron particle size) gave a retention time of 5.5 minutes for this compound. This method also provided excellent resolution of amphotericin B from the cofermented X component (25), another heptaene closely related to It. The mobile phase consisted of... 

When the aromatic heptaene, candicidin, was added to both sides of a bilayer under similar conditions, a cation-selective pore was produced (in contrast with the anion-selective pore produced by nystatin and amphotericin) [203]. This antibiotic forms a different type of pore, as unlike nystatin or amphotericin B it was equally effective when only added to one side of the membrane [255]. 

The soluble complexes of heptaenes commercially available are formulated with detergent-like substances, e.g. sodium desoxycholate or sodium lauryl sulphate, and do not form true solutions but consist of colloidal dispersions in an aqueous medium. The in vitro solubility of drugs with low aqueous solubility may be enhanced by coprecipitation with poly(vinyl pyrrolidone) (PVP) [376, 377]. The preparation of nystatin—PVP complexes has been described [378-380]. The solubility of PVP coprecipitates was eight to ten times greater than the parent compound [381] but the coprecipitates showed decreased antibiotic stability. 

Candicidin D is a heptaene macrolide antibiotic produced by S. griseus IMRU 3570 containing an aromatic moiety. It was first described by Lechevalier et al. in 1953 and named antibiotic C135, although it was renamed candicidin because of its strong... 

Bongkrekic acid 3-carboxymethyl-17-methoxy-6,18,21-trimethyldocosa-2,4,8,12,14,18,20-heptaene-dioic acid, M, 486.61. B.a. is one of 2 toxic antibiotics produced by Pseudomonas cocovenenans in spoiled bongkrek (a coconut product consumed in Indonesia). It is an inhibitor of adenine nucleoside translocation, and it affects carbohydrate metabolism. 

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