Macrolides compounds

A cytotoxic alkaloid has been isolated from the filamentous species Hapalosi-phon forUinalis strain V-3-1. This isolate was made from soil samples collected in the Marshall Islands in 1981. This strain produces the lipophilic compound hapalindole A, which has a broad range of antialgal and antimycotic activity (9). OscUlatoria acutissima strain B-1, isolated from a freshwater pond in Oahu, was found to produce two novel macrolide compounds termed acutiphycin and 20, 21-didehydroacutiphycin. These macrolides show cytotoxicity (KB and NIH/3T3) and antitumor activity (Murine Lewis lung carcinoma) (10). 

The gene cluster of S. venezuelae involved in the biosynthesis of 57 is notable for its inherent ability to produce two sets of related macrolides. Compounds 57/58 are representatives of these two sets that derive from 12- and 14-membered... 

More interestingly, as an oxidative condition with Mn(OAc)3, various macrolide compounds (230) are obtained in high yields by the treatment of bis(acetylacetate) (228) and bis(olefin) (229) with Mn(OAc)3 in acetic acid under highly diluted conditions (2 mM of substrate) [237,238]. This reaction proceeds as follows. The initial formation of a (3-keto ester radical via single electron oxidation by Mn(OAc)3 and its addition to olefin occur the formed benzylic radical is oxidized by Mn(OAc)3 to form a benzylic cation, then cyclization by oxygen of the enol form of the (3-keto ester occurs, and again this reaction sequence is repeated in another (3-keto ester group to ultimately form the macrolide compounds. 

Macrolide compounds with a hygrolide skeleton such as L-681,110 Bx (14 in Figure 3),44 leucanicidin (15),45 and bafilomycin Ai (16)46 produced by Streptomyces species were shown to have insecticidal activity by inhibiting H+-ATPase.47 They are useful as biological reagents. 

Sasaki, K., Satake, M., and Yasumoto, T. 1997. Identification of the absolute configuration of pectenotoxin-6, a polyether macrolide compound, by NMR spectroscopic method using a chiral anisotropic reagent, phenylglycine methyl ester. 

Sirolimus (rapamycin) is a macrolide compound related to erythromycin and tacrolimus. It binds to the same immunophilin as tacrolimus, but it does not inhibit calcineurin. Sirolimus blocks T-cell activation at a late stage, interfering with the signal from 1L2 receptors and receptors for other cytokines and growth factors, and so blocking the cytokine or growth factor-induced activation of the proliferation cell cycle response [409]. This powerful immunosuppressive... 

Among the many antibiotics isolated from the actinomycetes isthe group of chemically related compounds called the mac-mlides. In I9S0, picromycin, the first of this group to be identified as a macrolide compound, was first reported. In 1952. erythromycin and carbomycin were reported us new antibiotics, and they were followed in subsequent years by other macrolides. Currently, more than 40 such compounds ate known, and new ones are likely to appear in the future. Of all of these, only two, erythromycin and oleandomycin, have been available consistently for medical use in the United States. In recent years, interest has shifted away from novel macrolides isolated from soil samples (e.g.,. spiramycin, josamycin, and rosamicin), all of which thus far have proved to be clinically inferior to erythromycin and semisynthetic derivatives of erythromycin (e.g., clarithromycin and azithromycin), which have superior pharmacokinetic properties due to their enhanced acid stability and improved distribution properties. 

Ivermectin is a macrolide compound derived from abamectin, a metabolite produced by Streptomyces avermitilis. More precisely, it is a mixture of two compounds, 22,23-dihydroavermectin (80%) and 22,23-dihydroavermectin (20%) (12). It is widely... 

T. Yamaguchi, M. Nishimura, R. Okamoto, T. Takeuchi, and K. Yamamoto, Physicoechemical stability of glassy 16-membered macrolide compounds, Chem. Pharm. Bull. 41, 1812-1816(1993). 

The effects of other macrolide compounds on gastrointestinal motility were also investigated in conscious dogs. Oleandomycin, which has a 14-membered ring like EM, showed about one-tenth of the activity of EM in stimulating... 

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