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Biomedical subjects

H Naganawa

Publications and source records attributed to H Naganawa.

At least 91 records · Page 5Linked to original sources
PubMed1993

AB5046A and B, novel chlorosis-inducing substances from Nodulisporium sp.

Novel chlorosis-inducing substances, AB5046A and B, were isolated from the culture broth of a fungal strain. The producing organism, designated AB5046, was identified as a member of Nodulisporium. AB5046A and B were purified by extraction with EtOAc and silica gel chromatography. The structure of AB5046A and B were determined to be 2-butyryl-3,5-dihydroxy-cyclohex-2-ene-1-one and 2-acetyl-3,5-dihydroxy-cyclohex-2-ene-1-one, respectively, by spectroscopic analyses. AB5046A and B induced chlorosis against Japanese barnyard millet in vitro. The chlorosis activity of these compounds was stronger against monocotyledons than dicotyledons.

Animals↗
PubMed1993

Isolation and structure determination of novel phosphatidylinositol turnover inhibitors, piericidin B5 and B5 N-oxide, from Streptomyces sp.

In the course of a screening program for inhibitors of epidermal growth factor (EGF)-induced phosphatidylinositol turnover in human epidermoid carcinoma cell line A431, we discovered two novel compounds of the piericidin family from the culture broth and mycelia of a Streptomyces strain MJ288-OF3. We named them piericidin B5 and B5 N-oxide. By NMR and mass spectrometric analyses, the molecular formulas of piericidin B5 and B5 N-oxide were determined to be C27H41NO4 (MW 443) and C27H41NO5 (MW 459), respectively. Piericidin B5 and B5 N-oxide inhibited phosphatidylinositol turnover of A431 cells with IC50S of 10.0 micrograms/ml and 1.1 micrograms/ml, respectively.

Anti-Bacterial Agents↗
PubMed1993

Benastatins C and D, new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. Production, isolation, structure determination and biological activities.

Benastatin C, a new member of the benastatins, has been isolated from the culture broth of Streptomyces sp. MI384-DF12. The structure of benastatin C was elucidated as 2-decarboxy-benastatin A by NMR studies. Benastatin D, 2-decarboxybenastatin B, was derived from benastatin B. Benastatins C and D showed inhibitory activities against human pi class glutathione S-transferase (GST pi) and excellent stimulatory activities on the murine lymphocyte blastogenesis in vitro.

Animals↗
PubMed1993

Bequinostatins A and B new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. Production, isolation, structure determination and biological activities.

New benzo[a]naphthacenequinone metabolites, designated bequinostatins A and B, have been isolated from the culture broth of the benastatin-producing strain Streptomyces sp. MI384-DF12. The structures of bequinostatins A and B were determined by spectral analyses to be 5,6,8,13-tetrahydro-1,6,7,9,11-pentahydroxy-8,13-dioxo-3- pentylbenzo[a]naphthacene-2-carboxylic acid and 2-decarboxybequinostatin A, respectively. Bequinostatin A showed considerable inhibitory activity against human pi class glutathione S-transferase (GST pi).

Animals↗
PubMed1993

Delaminomycins, novel nonpeptide extracellular matrix receptor antagonist and a new class of potent immunomodulator. II. Physico-chemical properties and structure elucidation of delaminomycin A.

Delaminomycins, novel extracellular matrix receptor antagonists, have been isolated from a culture broth of Streptomyces albulus MJ202-72F3. The structure of delaminomycin A was determined to be 3-[[2-[(3E,5E)-2,8-dihydroxy-7-methyl-3,5-decadienyl]- 1,6,8- trimethyl-1,2,4a,5,6,7,8,8a-octahydro-1-naphthyl]carbonyl]-5- hydroxypyrrolidine-2,4-dione by analyses of spectral properties and chemical studies.

Adjuvants, Immunologic↗
PubMed1992

Inhibitory effects of polyethers on human immunodeficiency virus replication.

We examined the inhibitory activities of 10 polyether antibiotics on human immunodeficiency virus (HIV) type 1. These compounds caused concentration-dependent inhibition of HIV replication in primary infected cultures of human T-lymphoblastoid H9 cells. The ratio of 50% effective concentrations for cellular cytotoxicity (MTT assay) to antiviral activity (reverse transcriptase assay) was over 5. Anti-HIV activity was also observed in cultures of monocytic lineage U937 cells chronically infected with HIV.

Anti-Bacterial Agents↗
PubMed1992

Benastatins A and B, new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. II. Structure determination of benastatins A and B.

Benastatins A and B, new inhibitors of glutathione S-transferase, have been isolated from the culture broth of Streptomyces sp. MI384-DF12. By X-ray crystallography, benastatin A was determined to be 8,13-dihydro-1,7,9,11-tetrahydroxy-13-dimethyl-8-oxo-3-pentyl- benzo[a]naphthacene-2-carboxylic acid. The structure of benastatin B was elucidated by NMR studies.

Benz(a)Anthracenes↗
PubMed1992

Production of new anthracycline antibiotics 1-hydroxy-oxaunomycin and 6-deoxyoxaunomycin by limited biosynthetic conversion using a daunorubicin-negative mutant.

A limited biosynthetic conversion of some known anthracyclinones using a specific daunorubicin-nonproducing mutant provided four new anthracycline antibiotics: 1-Hydroxy-10-methoxycarbonyl-13-deoxocarminomycin; 1-hydroxy-13-deoxocarminomycin; 1-hydroxyoxaunomycin and 6-deoxyoxaunomycin. Their isolation and purification from bioconversion broth, structural determination and antitumor activities against leukemic L1210 cells are described.

Animals↗
PubMed1992

Photochemically obtained N-demethyl derivatives of anthracyclines.

New N-monodemethyl and N-didemethyl derivatives were obtained from seven N-dimethylamino sugar (rhodosamine)-containing anthracyclines by photochemical reaction and their in vitro bioactivities against L1210 cell culture were compared with those of their N-dimethyl parent compounds. N-Demethyl derivatives obtained from betaclamycin T (7-O-rhodosaminyl-beta-rhodomycinone) were much more cytotoxic while those from the other six antibiotics were rather less active as compared with their parent compounds. The N-demethylation also gave a considerably greater decrease in the inhibitory activity on RNA synthesis as compared to DNA synthesis, so that the N-demethyl derivatives showed smaller IC50 ratios on DNA/RNA than their parent compounds.

Animals↗