A novel neuritogenetic compound BU-4514N was isolated from the fermentation broth of Microtetraspora sp. T689-92. It showed significant NGF-mimic activity and antibacterial activity against Gram-positive bacteria. Structural studies revealed that BU-4514N was a new chemotype antibiotic related to lydicamycin.

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Rumbrin has been isolated from a fungus, Auxarthron umbrinum, by a screening program designed to find microorganism-produced cytoprotective substances. It was purified by use of column chromatography on silica gel, reversed phase HPLC and then isolated as fine red needles. Rumbrin prevented cell death caused by calcium overload and exhibited a potent inhibitory activity against lipid per oxidation.

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The structure of rumbrin (Fig. 1), a new cytoprotective substance, was elucidated by NMR spectral analysis. Rumbrin was found to possess a novel skeleton containing α-pyrone, tetraene and pyrrole moieties.

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Pyrrolostatin, a new lipid peroxidation inhibitor, was isolated from the culture of Streptomyces chrestomyceticus EC40. The structure was determined to be 4-geranylpyrrole-2-carboxylic acid on the basis of its spectroscopic and physico-chemical properties. Pyrrolostatin inhibited lipid peroxidation in rat brain homogenate.

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Lagunamycin, a novel 5-lipoxygenase inhibitor, was isolated from the culture broth of Streptomyces sp. AA0310. This compound showed potent rat 5-lipoxygenase inhibitory activity (IC₅₀ 6.08μM) without lipid peroxidation.

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A novel human leukocyte elastase inhibitor, FR901277 was discovered in the fermentation broth of Streptomyces resistomycificus No. 7622. FR901277 has a molecular weight of 961 and a molecular formula of C₄₇H₆₃N₉O₁₃. The mode of inhibition is competitive, with a Ki of 1.2×10^-8M. Oral administration of FR901277 at doses from 32 to 320mg/kg significantly prevented human leukocyte elastase-induced foot edema in mice.

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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 π).

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A new antitumor antibiotic verucopeptin was isolated from the culture broth of Actinomadura verrucosospora Q886-2. It showed potent cytotoxicity and specific in vivo activity against B16 melanoma. Maximum T/C value (162%) was obtained by Q1D×1 treatment schedule.

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The structure of a new antibiotic verucopeptin has been determined by the spectroscopic analyses and chemical degradation studies. It is a 19-membered cyclodepsipeptide which is structurally related to azinothricin and A83586C.

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Respinomycins are a novel group of anthracycline antibiotics produced by Sreptomyces xanthocidicus. Respinomycins Al, A2, B, C and D were isolated by EtOAc extraction, silica gel column chromatography, centrifugal partition chromatography and preparative silica gel thin layer chromatography. Respinomycins Al and A2 induced the terminal differentiation of human leukemia K-562 cells.

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Respinomycins A1, A2, B, C and D were revealed to be novel anthracycline antibiotics with molecular formulae of C₅₁H₇₂N₂O₂₀, C₄₃H₅₈N₂O₁₅, C₃₅H₄₃NO₁₄, C₃₆H₄₅NO₁₄ and C₅₁H₇₀N₂O₂₂, respectively. Their structures were determined by means of ¹H-¹H COSY, ¹³C-¹H COSY and HMBC spectra. The structure of the aglycone of respinomycins was unambiguously determined by LSPD experiments and NOESY. The common skeleton of respinomycins is a new type and is distinguished from that of the nogalamycin group.

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New β-1, 3-glucan synthase inhibitor (BU-4794F) was isolated from the culture broth of Gilmaniella sp. FA4459. Structural studies indicated that it was a novel member of the papulacandin group of antibiotics.

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Several chlorinated metabolites with nematicidal, antimicrobial, and cytotoxic activities were isolated from submerged cultures of the ascomycete Lachnum papyraceum. Three compounds were identified as (+)-mycorrhizin A (3), (+)-chloromycorrhizin A (4) and (+)-dechloromycorrhizin A (5). The occurrence of 5 as a natural product is new. Two compounds, lachnumon (1) and lachnumol A (2), were found to be new fungal metabolites with cytotoxic, nematicidal and antimicrobial activities.

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The structures of two new biologically active chlorinated metabolites isolated from submerged cultures of the ascomycete Lachnum papyraceum have been elucidated by NMR and mass spectroscopy. The compounds, lachnumon (1) and lachnumol A (2), which structurally are related with mycorrhizin A that also is produced by the fungus, contain an unusual chlorinated epoxide group.

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An actinomycete strain SC-4710, a new soil isolate, was found to produce a new macrolide antibiotic, PC-766B. Chemotaxonomic analysis of the producing organism revealed that the cells of SC-4710 had type IV cell wall, type A whole cell sugar pattern, type PII phospholipids, menaquinone MK-8(H₄), cellular fatty acids comprising straight-chain saturated, unsaturated and tuberculostearic acids, and mycolic acids. The strain was identified as Nocardia brasiliensis (Lindenberg) Pinoy. The antibiotic, PC-766B, was active against Gram-positive bacteria, and some fungi and yeasts, but inactive against Gram-negative bacteria. It also showed antitumor activity against murine tumor cells in vitro and in vivo, and a weak inhibitory activity against Na⁺, K⁺-ATPase in vitro.

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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-octahydrol-naphthyl]carbonyl]-5-hydroxypyrrolidine-2, 4-dione by analyses of spectral properties and chemical studies.

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Gilvocarcin V was chemically transformed to alter its biological activities as well as its solubility by mainly focusing on the vinyl side chain. The oxirane and oxime derivatives showed slightly decreased in vivo antitumor activity, while the aminoethylmorpholine derivative turned out to be soluble in some organic solvents.

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Cephalosporins with new aminoimidazole heterocycles at C-7 have been synthesized by reaction of anti-α-aminooximes with C-7 dihaloisocyanocephalosporins esters or by direct condensation of 2-fluoroimidazoles with C-7 aminocephalosporins esters. These compounds combine a broad spectrum of antibacterial activity, including Gram-negative and Gram-positive organisms with a good β-lactamase stability. Activity is discussed in terms of its relationship to the pKa. of the C-7 aminoimidazole heterocycle, basic C-7 aminoimidazole residues gave cephalosporins with the best β-lactamase stability but the poorest activity against Gram-positive organisms. An additional interesting property of the C-7 imidazolylaminocephalosporins is the oral activity present in some compounds of this series.

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