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OC-108 is a novel sclerosing agent for hemorrhoids, containing aluminum potassium sulfate (alum) and tannic acid as its main ingredients. In clinical studies, OC-108 injection therapy for severe internal hemorrhoids proved to be highly effective, not only on bleeding but also for prolapse, and the effects were comparable to hemorrhoidectomy. The aim of this study was to elucidate the mode of action by administrating the agent s.c. to mice and rats. In response to OC-108 injection, inflammation with necrosis developed at an early stage followed by granuloma formation with fibrosis at the injection site. Necrotic debris with aluminum was observed in the granuloma for a long period. Alum, as well as OC-108, induced vascular permeability, leukocyte infiltration, and granuloma formation; however, tannic acid did not. On the other hand, tannic acid inhibited leukocyte infiltration induced by alum but did not inhibit granuloma formation. These results indicate that OC-108 causes sclerosis and retraction of hemorrhoids through fibrosis associated with granulomatous chronic inflammation induced by the main active ingredient alum and that the adjunct ingredient tannic acid reduces excessive acute inflammation induced by alum. Keywords:: OC-108, aluminum, tannic acid, granuloma, fibrosis

Here we present results obtained in our group from cell-based screenings of microbial secondary metabolites using intact microbial and mammalian cells having specific functions. We present summaries of the following five categories of compounds and the strategies that were used to identify them. (1) Antibacterial agents targeting cell wall peptidoglycan synthesis as well as active agents against organisms other than bacteria were identified by a combination of Bacillus subtilis and Mycoplasma as test organisms. (2) Antimetabolites, such as herbicidal agents targeting glutamine synthase, were identified using B. subtilis grown on minimal medium with or without the addition of glutamine and folate inhibitors by combination of B. subtilis and Enterococcus faecium, which have distinct folate metabolic pathways. (3) Among inhibitors of lipid metabolism, acyl-CoA synthetase inhibitors were identified using two mutants of C. lipolytica with different deletion sites in the fatty acid metabolic pathways, HMG-CoA synthase inhibitors were identified using Vero cells cultured in the presence and absence of mevalonate, and anti-atherosclerosis agents were identified using macrophages. (4) IL-6 inhibitors were detected by a combination of IL-6-dependent and independent murine hybridoma MH60 cells, and (5) Small molecules with TNF-like activities were identified using a mouse neuroblastoma cell line. Some advantages of such screening method and the significance of the identified compounds are discussed. (Contributed by Satoshi OMURA, M.J.A., Feb. 12, 2004)

通気時の浮遊化限界動力と通気動力との間に簡単な関係を仮定し, 気液固撹拌槽における浮遊化限界動力を推定する新しい相関法を提案した. 通気時の浮遊化限界動力は, 通気動力, 無通気時の浮遊化限界動力, 撹拌翼の傾斜角度で相関される. この相関式を使用する事により, 既往の文献値が精度良く整理できた. また, 小型装置を用いた合成反応実験より, 気固反応を完結させるためには, 相関式により算定した浮遊化限界動力以上の撹拌動力が必要であることを実証し, 相関式の有用性を明らかにした.

Six new bicyclic peptides, celogentins D–H ( 1–5 ) and J ( 6 ) have been isolated from the seeds of Celosia argentea, and the structures including its absolute stereochemistry were determined by using extensive NMR methods and chemical means. Celogentins E–H ( 2–5 ) and J ( 6 ) showed potent inhibition of tubulin polymerization, while the inhibitory activity of celogentin D ( 1 ) was modest. Structure–activity relationship study indicates that ring size of the bicyclic ring system including unusual βs-Leu, Trp, and His residues would be important for their biological activity.

A compact I2-stabilized frequency-doubled Nd:YAG laser has been developed for a long gauge block interferometer. The laser frequency stabilization is realized by the third-harmonic technique, where a fast frequency modulation (20 kHz) is applied to the piezoelectric transducer attached on the laser crystal. The relative uncertainty of the laser frequency has reached 3.6×10-12 for a 0.01-s averaging time. It is theoretically indicated that the phase error in the interferometric measurement due to the optical frequency modulation is sufficiently small to measure the long gauge block up to 1000 mm. Long gauge block measurement up to 1000 mm was successfully demonstrated with the developed I2-stabilized frequency-doubled Nd:YAG laser.

A new two-color heterodyne interferometer using an optical grating was proposed for measuring the refractive index of air. The heterodyne modulation is realized by moving the diffraction grating. The method allows us to measure the refractive index with high accuracy by using a 1:06 lm YAG laser and its second-harmonic wave because two beams (the fundamental and the second-harmonic wave) are in common path completely. Moreover, good signal-to-noise ratio (SNR) can be obtained by the heterodyne interference. Using the refractive index calculated by Edl e equation as a reference, that measured by present method was experimentally evaluated having an accuracy of about 1 � 10 � 6 within a distance of 100 mm. 2002 Elsevier Science B.V. All rights reserved.

Some phase errors in a two-color interferometer result in a large uncertainty in length measurement due to the large A coefficient. We analyzed three kinds of phase errors, correlation, semi-correlation and non-correlation errors, and presented a weight average method to deal with different errors by using different weight factors. The uncertainties in length measurement can be reduced without effects on the resolution of length measurement. The experimental results show that the length can be obtained with a standard deviation of approximately 0.1 μ m by measuring the phase of the interference fringe using a heterodyne interferometry and processing the measured data using a weight average method.

With guidance of Pyricularia oryzae bioassay, daphnoretin (1), (+)-nortrachelogenin (2), genkwanol A (3), wikstrol A (4), wikstrol B (5) and daphnodorin B (6) were isolated from the roots of Wikstroemia indica. Compounds 1-6 induced morphological deformation of P. oryzae mycelia with MMDC values of 68.4 +/- 1.3, 31.3 +/- 1.8, 45.8 +/- 0.5, 70.1 +/- 2.4, 52.3 +/- 0.9 and 73.7 +/- 1.6 microM, respectively. Compounds 3-6 showed moderate activity against microtubule polymerization with IC50 values of 112 +/- 4, 131 +/- 3, 184 +/- 6 and 142 +/- 2 microM in vitro, respectively. Compounds 2, 3, 5 and 6 were moderately active against HIV-1 in vitro. The findings of bioactivity of 1-6 support the antifungus, antimitosis and anti-HIV-1 uses for W. indica roots.

Microtubules (MT) are cylindrical polymers of the protein tubulin (TN) alpha, beta-heterodimer, and are known to be the main component of spindles in mitotic apparatus of eucaryotic cells. MT are also involved in many other basic and essential cell functions. There are a number of natural and synthetic compounds that interfere with MT function to cause the mitotic arrest of eucaryotic cells. Such antimitotic agents show a broad biological activity, and can be used for medicinal and agrochemical purposes. On the other hand, they are important also as the biochemical tools for understanding the dynamics of MT network. Most of such antimitotic agents, with a few exceptions, bind to beta-TN. Among them, colchicine (CLC), vinblastine and taxol have played major roles in practical uses as well as in biochemical studies of MT functions. They all bind to beta-TN but their binding sites are different. We have worked on a variety of antimitotic agents that bind to either of colchicine-site, vinblastine-site and taxol-site, in discovery, structures, biological actions and/or interactions with TN. In this paper, the results of our studies on CLC-site ligands were summarized; (1) synthetic analogs of combretastatin A-4 (CBS A-4), isolated as a cytotoxic compound produced by a species of South African tree Combretum caffrum, (2) curacin A (CU-A), a cytotoxic metabolite of a marine cyanobacteria Lyngbya majuscula, and its related compounds. Interactions of these compounds with TN were studied and structure-activity relationships of these two classes of compounds were discussed.

We present here a new method for real-time absolute-distance measurement. It is based on a two-wavelength superheterodyne interferometer. It is performed by simultaneous measurement of its synthetic wavelength and one of two wavelengths. The phase of one of two wavelengths is electrically separated from the synthetic one, thus maintaining the resolution of a one-wavelength heterodyne interferometer. Two He-Ne lasers operating at 1 = 633 nm and 2 = 612 nm are incorporated into the measuring system, as two wavelength sources, resulting in the synthetic wavelength of s = 18.4 µm. Thus, the proposed system has a range of 9.2 µm with nanometre resolution.

A high-resolution distance meter was fabricated using optical waveguide modulators. An optical intensity modulation frequency of 28 GHz was utilized for the displacement measurement when the driving frequencies to the optical modulators were around 14 GHz. The distance meter was evaluated in the National Research Laboratory of Metrology (NRLM) tunnel, which is a semi-underground tunnel. The measurement resolution is 1 and for a distance of 5 and 100 m, respectively, in one standard deviation after correction of the cyclic error. Furthermore, cyclic errors are examined for 28 GHz optical intensity modulation.

The red pigmented strain F-1-1 of Serratia marcescens shows a strong antagonism against Phytophthora capsici, the pathogen of damping-off of cucumber seedlings, and its antagonistic activity is due to the production of antibiotic red pigments. In the present study, purification and identification of the red pigments produced by the strain F-1-1 were performed. The water-insoluble red pigments were extracted from cultures on agar plates with ethanol and then chloroform, and purified by silica gel column chromatography. An active substance was isolated using the antifungal activity assay and was identified as prodigiosin, a known compound based on the spectral data. Purified prodigiosin inhibited the germination of cystospores and the growth of the fungal hyphae of P. capsici. It also showed antimicrobial activity against some plant-pathogenic fungi including Cochliobolus miyabeanus, Pythium spinosum, P. ultimum and against plant pathogenic bacteria including, Clavibacter michiganensis subsp. michiganensis and Erwinia carotovora subsp. carotovora. These results suggest that S. marcescens F-1-1 could be used as a biocontrol agent against many plant diseases other than cucumber damping-off.

Collisionally activated dissociation (CAD) of [M+H]+ of ustiloxins and phomopsins was examined. Fragments of ustiloxins were formed by the cleavage of O(1)-C(2) and the peptide chain to form “a”, “b”, “x”, and “y” series ions, and of the C(9)-C(10) bond to form ions “M-Bz” and “b-Bz”. Phomopsins gave the “b” and “y” series ions. The difference may be at least partly explained by different hydrogen bond-forming characteristics of ustiloxins and phomopsins.

Microtubules (MT), composed of a protein tubulin (TN) alpha,beta-heterodimer with concomitant other proteins, microtubule associated proteins (MAPs and tau), are known to be the main component of spindles in a mitotic apparatus of eucaryotic cells, and are also involved in many other basic and essential cell functions. There are a number of natural and synthetic compounds that interfere with MT function to cause the mitotic arrest of eucaryotic cells. Such antimitotic agents show a broad biological activity, and can be used for medicinal and agrochemical purposes. On the other hand, they are also important as the biochemical tools for understanding the dynamics of MT network. Most of such antimitotic agents, with a few exceptions, bind to beta-TN. Among them, colchicine (CLC), vinblastine (VLB) and taxol have been of major importance in biochemical studies of MT and in studies of their intracellular functions. The former two both inhibit MT assembly but their binding sites on beta-TN are different; CLC-site and VLB-site, and many MT inhibitors bind to either sites. Taxol bind to TN at a site other than CLC-site and VLB-site, and promote MT assembly. We have worked on a variety of antimitotic agents that bind to CLC, VLB or taxol-site, in discoveries, structures, biological actions and/or interactions with TN. In this paper, I summarized the results of our studies on VLB-site ligands; (1) rhizoxin (RZX), isolated as a phytotoxin produced by a plant pathogenic fungus, and its related compounds, (2) derivatives of ansamitocin P-3 (ASMP3) (maytansinoid: MAY), isolated as a cytotoxic metabolite of an Actinomycete, (3) phomopsin A (PMSA), isolated as a mycotoxin produced by a plant parasitic fungus, (4) dolastatin 10 (DLS10), isolated as a cytotoxic metabolite of a see animal, (5) ustiloxins (USL) A-F, isolated as a mycotoxin produced by a plant pathogenic fungus, (6) arenastation A (ARSA), isolated as a cytotoxic metabolite of a sponge, and its synthetic analogs. From our studies on interactions of these VLB-site ligands with TN, we showed that the presence of a distinct RZX/MAY-binding site which only partially overlap with VLB-site, and that PMSA, DLS10, USLs and ARSA bind to the RZX/MAY site. RZX, ASMP3 and ARSA inhibit the growth of a variety of fungi, including Aspergillus nidulans. In order to obtain information as to the drug-TN interaction at the RZX/MAY site, RZX-resistant beta-TN gene mutants were isolated from RZX-sensitive wild-type A. nidulans. In all the beta-TN gene mutants, single amino acid (100th) alteration, asparagine-to-isoleucine, was observed. Sequence displacement experiments confirmed that this alteration conferred resistance to RZX and ASMP3, and also to ARSA. This resistance mechanism was further verified with yeasts Schizosaccharomyces pombe and Saccharomyces serevisiae. All the natural ligands mentioned above show potent cytotoxicity against human and murine tumor cells, but VLB, PMSA, DLS10 and USLA are inactive to both RZX-sensitive and -resistant fungal strains.

Ustiloxin F, a microtubule inhibitor, was isolated as a minor metabolite of Ustilaginoidea virens. The structure was determined from the spectral data and by chemical interrelation to ustiloxin B through reductive removal of the sulfoxide-containing side chain of ustiloxin B to give ustiloxin F. Ustiloxin F inhibited microtubule assembly with an IC50 value of 10.3 microM.

A series of side chain-modified analogs of curacin A, a powerful antimitotic agent isolated from a Caribbean cyanobacterium was synthesized and the effect of these compounds on in vitro microtubule polymerization was examined. The analogs showed weak or no anti-tubulin activity, suggesting that the whole side chain structure of curacin A is required for the interaction with tubulin.

A new furostanol saponin, named hypoglaucin F, was isolated from the rhizomes of Dioscorea collettii var. hypoglauca, along with seven known compounds. On the basis of detailed chemical and spectroscopic evidence, the structure of hypoglaucin F was determined as (25S)-26-O-β- d -glucopyranosyl 22-hydroxy-5-en-furostane-3β, 26, 27-triol 3-O-α- l -rhamnopyranosyl-(1 → 2)-[α- l -rhamnopyranosyl-(1 → 4)]-β- d -glucopyranoside .

Among new taxoids, taxuspines A ∼ H and J ∼ T ( 1 ∼ 19 ), and known taxoids 20 ∼ 56 containing taxol ( 56 ) and taxol-type compounds 37 ∼ 44 with an N -acylphenylisoserine group at C-13 and an oxetane ring at C-4 and C-5 isolated from stems and leaves of the Japanese yew Taxus cuspidata Sieb. et Zucc., non-taxol-type compounds 4 and 32 remarkably reduced CaCl 2 -induced depolemerization of microtubules. Furthermore, some non-taxol-type compounds 2 , 3 , 9 , 24 , 25 , 27 , and 28 increased cellular accumulation of vincristine in multidrug-resistant tumor cells as potent as verapamil, while taxol ( 36 ) and taxol-type compounds did not show such an activity. In addition, the non-taxol-type compounds enhancing vincristine accumulation inhibited competitively binding of azidopine to P-glycoprotein. These results suggest that some non-taxol-type taxoids may be useful for overcoming multidrug resistance in tumor cells.

The magnesium bromide diethyl etherate (MgBr 2 ·OEt 2 )-methyl sulfide (Me 2 S) system is useful for the mild and chemo-selective deprotection of p -methoxybenzyl (PMB) ether in the presence of 1,3-diene, t -butyldimethylsilyl (TBDMS) ether, benzoate, benzyl ether and acetonide.

The synthesis and biological activity of a series of 5-[(2,5-dihydroxybenzyl)amino]salicylic acid derivatives ( 3–6 ) as analogs of the active partial structure ( 2 ) of the potent EGF-R tyrosine kinase inhibitor lavendustin A ( 1 ) are described. Analogs with an electron-withdrawing group in place of the carboxyl group of 2 showed activity. The N -hexylsalicylamide analog 6b (IC 50 =0.9 μM) was about four times more potent than 2 .

Previous studies by our and other groups have shown that microbial products containing more than one epoxide group, including eponemycin, radicicol, depudecin and AGM-1470, exhibit anti-angiogenic activity in an in vivo assay system involving chorioallantoic membranes (CAMS) of growing chick embryos. Based on these findings, rhizoxin, a microbial metabolite that contains two epoxide groups and exhibits anti-tubulin activity, was tested for anti-angiogenic activity in a CAM assay system. Rhizoxin caused dose-dependent inhibition of embryonic angiogenesis, the ID 50 value being 2 ng (3.2 pmol) per egg. In addition, this compound (2 mg/kg i.p.) significantly suppressed neovascularization induced by M5076 mouse tumor cells in a mouse dorsal air sac assay system, compared to the vehicle alone (P < 0.05). These results indicate that rhizoxin is a novel inhibitor of angiogenesis, and that it has potential as a new therapeutic agent for cancer.

Cytosolic-nuclear tumor promoter-specific binding protein (CN-TPBP) was photoaffinity-labeled with a specific ligand, 3beta,5alpha-dihydroxycholestan-6-one (YS-64). Analysis by ODS-HPLC of peptide fragments obtained from the labeled CN-TPBP by trypsinization indicated the existence of a single specifically labeled site. Affinity gels for the purification of CN-TPBP were then prepared. As ligands for the affinity gels, 12-O-tetradecanoylphorbol 13-acetate (TPA), a typical phorbol-type tumor promoter, and benzolactam-V8-310 (BL-V8-310), a structural/biological mimic of teleocidin-class tumor promoters, were adopted. The use of these gels afforded a protein that showed a single band of 58 kDa on SDS-PAGE.

A cytokinin isolated from the fluid endosperm of Cocos mucifera L. (coconut milk), accounting for more than 20% of the total cytokinin activity, was structurally analyzed by NMR techniques, mass spectrometry, and sugar analysis by high performance liquid chromatography (HPLC). The planar structure of the cytokinin was deduced from its NMR and mass spectrometric data. The structure of the sugar moiety, including its absolute structure, was determined by HPLC analysis of alditol acetates and aldononitrile acetates derived from the cytokinin. The configuration of the sugar-sugar bonds was determined by NMR, and the structure was finally identified as 14-O-(3-O-[-beta-D-galactopyranosyl-(1--2)-alpha-galactopyranosyl-(1--3)- alpha-L-arabinofuranosyl]-4-O-(alpha-L-arabino-furanosyl)-beta-D- galactopyranosyl)-trans-zeatin riboside.

Curacin A ( 1 ), a novel antimitotic agent, was synthesized in a highly stereo-controlled manner. The four stereoisomers of a partial structure at the thiazoline moiety, 2 were also synthesized to aid in elucidation of the absolute configurations of three chiral centers in curacin A. The effects on porcine brain tubulin assembly of several synthetic compounds related to curacin A were examined.

In optically active phthalimide analogs of thalidomide, the inducer-specific TNF-α production-enhancing and -inhibiting activities are separated. This implies that the target molecules of the two activities are different.

We have developed a versatile method for the synthesis of enantiomerically pure cis -2-methylcyclopropanecarboxylic acid (−)- 2 , a component of curacin A, and its enantiomer, (+)- 2 . Double-asymmetric Simmons-Smith cyclopropanation of the dienes 5 and 9 derived from diethyl L -tartrate proceeded with excellent diastereofacial selectivity (>99% de) to give the dicyclopropanes 6 and 10 , which were converted to both enantiomers of 2 .

Coordination of an alkali metal cation (A) to two proximate oxygens in a molecule (molecular weight, M) affords a prominent [M+A] + ion peak in fast atom bombardment mass spectrometry. Relative affinities of various diols and other O-containing compounds for Na + were determined from the intensities of the [M+Na] + ions relative to that of 1,2-hexadecanediol ( 1 ).

Curacin A (1), a novel antimitotic agent, was synthesized in a highly stereo-controlled manner. The key steps were (1) an asymmetric allylation using a chiral allyltitanium reagent and a double-asymmetric Simmons-Smith cyclopropanation to introduce three chiral centers, (2) Wittig and Wittig-Horner reactions to construct the C(3–4) and C(7–10) alkenes, and (3) a direct conversion of the thiazolidine to the thiazoline.

Phenylphthalimides (2-phenyl-1H-isoindole-1,3-diones) were prepared and their effects on tumor necrosis factor alpha (TNF-alpha) production by human leukemia cell line HL-60 stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA) were examined. An analysis of the structure-activity relationships of the phenylphthalimides indicated that potent enhancing activity on TPA-induced TNF-alpha production by HL-60 cells requires medium-sized substituent(s) at the ortho position(s) of the phenyl group; 2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione (PP-33) increased the TNF-alpha production to more than 600% at the concentration of 1 x 10(-5) M. Introduction of a nitro group at the phthalimide moiety of PP-33 enhanced the activity; 2-(2,6-diisopropylphenyl)-4-nitro-1H-isoindole-1,3-dione (4NPP-33) and its 5-nitro isomer (5NPP-33) enhanced the TNF-alpha production to more than 800% and 700%, respectively, at the concentration of 1 x 10(-5) M. Introduction of fluorines into the phthalimide moiety of PP-33 greatly lowered the concentration of the compound necessary to elicit the TNF-alpha production-enhancing activity; 2-(2,6-diisopropylphenyl)-4,5,6,7-tetrafluoro-1H-isoindole-1,3-dio ne (FPP-33) showed the activity at nanomolar concentration, with the optimum concentration of 1 x 10(-7) M.

Superposition of different-wavelength, multimode- and single-mode laser diode beams is investigated to locate the fringe of zero interference order in a Twyman-Green interferometer. The possibility of central fringe detection using three multimode laser diodes or one single-mode together with a pair of multimode laser diodes is shown. If a single-mode laser diode is applied, a simultaneous fringe-counting technique for displacement measurement is available. The influence of the angle between wavefronts entering the interferometer is analyzed. A repeatability of about 5 nm is shown for surface position determination when using three-beam source.

Homochiral 1- O -acyl and 1- O -acyl derivatives of myo -inositol 3,4,5-trisphosphate were designed and synthesized as novel analogues of phosphatidyl- myo -inositol 3,4,5-trisphosphate. 1- O -Octadecyl and 1- O -stearoyl analogues inhibited the synthesis of phosphatidyl- myo -inositol 3,4-bisphosphate from phosphatidyl- myo -inositol 3,4,5-trisphosphate catalyzed by PIns-3,4,5-P 3 5-phosphatase. These compounds may act as competitors in the enzyme reaction, suggesting that they may be useful in studies of the role of phosphatidyl- myo -inositol 3,4,5-trisphosphate as a candidate second messenger in cellular signal transduction.

Pathogenic Nocardia spp. converted rokitamycin, midecamycin and erythromycin into inactive metabolites, the structures of which were determined from NMR and mass spectral data. Depending on the species of Nocardia, these macrolides underwent phosphorylation at 2′-OH, hydrolysis of the 4″-O-acyl group, glycosylation at 2′-OH and/or reduction of the 18-formyl group. Full 1H and 13C assignments are presented and some solvent effects are described.

Possible involvement of the peripheral-type benzodiazepine receptor (PBR) in hemin/protoporphyrin-induced erythroid differentiation of human leukemia K562 cells was investigated by the use of the ligands, diazepam and PK11195. Diazepam itself exhibited differentiation-inducing activity on K562 cells. The PBR-specific antagonist, PK11195, dose-dependently inhibited both diazepam-induced and hemin/protoporphyrin-induced K562 cell differentiation. The results imply that PBR is involved in the erythroid differentiation of K562 cells.

Benzylphthalimide analogs (P1P's) and phenethylphthalimide analogs (P2P's) have been found to exhibit thalidomide-like activity on the production of tumor necrosis factor (TNF)-α by the human leukemia cell line, HL-60, stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA). Structure-activity relationships are discussed on the basis of the TNF-α production-enhancing activity. Benzylphthalimide (P1P-00) exhibited activity which is weaker than that of thalidomide, but introduction of a methyl group at the ortho-position of the benzyl moiety (P1P-10) resulted an increase to a level comparable with that of thalidomide. Phenethylphthalimide (P2P-00) is more potent than thalidomide, and its fluorinated derivative, 2-phenethyl-4, 5, 6, 7-tetrafluoro-1H-isoindole-1, 3-dione (FP2P-00), exhibited potent activity at very low concentrations.

The ability of strains of Bacillus, Staphylococcus, Pseudomonas, and Escherichia coli to inactivate rifampicin was tested. Most Bacillus strains were found to inactivate rifampicin. Two modes of inactivation were identified; one was phosphorylation and the other involved decolorization. Presence or absence of either mechanism appeared unrelated to the phylogenetic relatedness of strains. None of the other organisms could inactivate this antibiotic.

DNA-binding ability of five non-diynene dynemicins and four related synthetic aza -anthraquinones ( 1–4 ) was studied by measurements of UV absorption shifts and electrophoretic behavior of the complexes with DNA.

Ustiloxin A is a modified peptide derived from false smut balls on rice panicles, caused by the fungus Ustilaginoidea virens; structurally, it resembles phomopsin A. Ustiloxin A is cytotoxic and is an inhibitor of microtubule assembly in vitro. Because of its resemblance to phomopsin A, we examined its interaction with tubulin and compared the results with those obtained with phomopsin A and dolastatin 10, both of which were found previously to have very similar effects. We determined that ustiloxin A inhibited the formation of a particular intra-chain cross-link in beta-tubulin, as do vinblastine, maytansine, rhizoxin, phomopsin A, dolastatin 10, halichondrin B and homohalichondrin B; this is in contrast to colchicine and podophyllotoxin which do not inhibit formation of this cross-link. Ustiloxin A also inhibited the alkylation of tubulin by iodo[14C]acetamide, as do phomopsin A and dolastatin 10; vinblastine was almost as potent as inhibitor of alkylation as ustiloxin A, whereas maytansine, halichondrin B and homohalichondrin B have little or no effect. In addition, ustiloxin A inhibited exposure of hydrophobic areas on the surface of the tubulin molecule. In this respect, ustiloxin A was indistinguishable from phomopsin A but slightly more effective than dolastatin 10 and considerably more effective than vinblastine; this provides a strong contrast to maytansine, rhizoxin, and homohalichondrin B which have no effect on exposure of hydrophobic areas and to halichondrin B which enhances exposure. Lastly, ustiloxin A strongly stabilized the binding of [3H]colchicine to tubulin. The combination of ustiloxin A with cholchicine stabilized tubulin with a half-life of over 8 days, comparable with results obtained with phomopsin A and colchicine. A comparison of the structures of ustiloxin A, phomopsin A and dolastatin 10 raised the possibility that the strong stabilization of the tubulin structure may require a short segment of hydrophobic amino acids such as the modified valine-isoleucine sequence present in all three compounds. The rest of the structure, specifically the large ring of ustiloxin A and phomopsin A, may serve to place this sequence in an appropriate conformation to interact with tubulin.

A series of aza-combretastatin was synthesized and their activity against microtuble assembly was evaluated. N-Benzylaniline analogs with a variety of side chains (10b-10i) showed moderate to excellent inhibitory activity while benzanilide analogs (8, 9 and 12) had little activity.

The effect of thalidomide [racemic (DL-) form and optically pure (D- and L-) forms] on tumor necrosis factor (TNF) alpha production by human leukemia cell lines (HL-60, K562 and U937) stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA) was investigated. Though thalidomide has been regarded as a specific inhibitor of TNF-alpha production, our study indicated that all forms of thalidomide enhanced (but did not inhibit) the TPA-induced TNF-alpha production by the human leukemia cell lines investigated. The effects of thalidomide on TNF-alpha production might be cell type-specific.

Three new taxoids, taxuspines A ∼ C (1 ∼ 3), possessing different skeletons from usual taxane diterpenoids consisting of a 6/8/6-membered ring system have been isolated together with known taxoids (4 ∼ 12) from stems of the Japanese yew Taxus cuspidata Sieb. et Zucc. and the structures elucidated on the basis of spectroscopic data. Most of the taxoids increased cellular accumulation of vincristine in multidrug-resistant tumor cells, while taxol (12) did not show such an activity. The taxoids (1 ∼ 11) showed no or weak cytotoxicity and among them, 2 and 6 reduced appreciably CaCI2-induced depolymerization of microtubules. These results suggest that some taxoids may be useful for overcoming multidrug resistance in tumor cells.

A fluorescent probe (20-demethoxy-20-[3-[[[5-(dimethylamino)naphthalen-1-yl]sulfonyl] amino]propyl]maytansinol 3-isobutyrate, Dan-PDM-3) and a photoaffinity labeling reagent (20-demethoxy-20-[(p-azidobenzoyl)oxy]maytansinol 3-isobutyrate, DABMI) were prepared by derivatization of ansamitocin P-3 (ASMP-3), a maytansinoid. Dan-PDM-3 consists of a tethered dansyl moiety and a maytansinoid moiety. DABMI contains a p-azidobenzoyl group instead of the tethered dansyl moiety of Dan-PDM-3. These compounds were synthesized by reacting 20-demethoxy-20-hydroxymaytansinol-3 isobutyrate (PDM-3) with the corresponding alkyl halide or benzoic acid. Both inhibit tubulin polymerization as potently as ASMP-3 and compete with ASMP-3 for binding to tubulin. The inhibition constants (Ki) of DABMI for the binding to tubulin of rhizoxin and ASMP-3 were 0.54 and 0.36 microM, respectively, which were nearly equal to the dissociation constant (Kd = 0.43 microM) of DABMI measured by the use of [14C]DABMI. The results suggest that Dan-PDM-3 and DABMI interacted with tubulin at the same site as rhizoxin and maytansine. DABMI is irreversibly bound to tubulin upon irradiation. Dan-PDM-3 and DABMI should be useful probes for studying the binding site.

The construction in optically pure form of the key building blocks, arising from our retrosynthetic analysis of the antitumor macrolide rhizoxin is described.

The first total synthesis of the antitumor macrolide, rhizoxin in a highly stereocontrolled manner is described.

Rifampicin (1) was converted into four inactivated products by pathogenic Nocardia, RIP-1 and RIP-2 by N. brasiliensis and RIP-3 and RIP-4 by N. otitidiscaviarum. MS and NMR analysis showed the compounds to be 3-formyl-23-[O-(beta-D-glucopyranosyl)]rifamycin SV (2), 23-[O-(beta-D-glucopyranosyl)]rifampicin (3), 21-(O-phosphoryl)rifampicin (4) and 3-formyl-21-(O-phosphoryl)-rifamycin SV (5), respectively.

Yeast fatty-acid synthase (FAS) inhibition by cerulenin analogs with varying side-chain lengths was compared with that of cerulenin, tetrahydrocerulenin and iodoacetamide. Although inhibition by cerulenin was the highest, the analogs having (E,E)-delta 7,10 double bonds showed high inhibition. This strongly suggests that the (E,E)-delta 7,10 double bonds play an important role in the interaction of the inhibitors with the enzyme. It was suggested that the size of the hydrophobic cavity in the condensing enzyme terminates fatty-acid chain elongation by decreasing inhibition by the C18 analog. Like cerulenin itself, the shortest analog (C6) did not induce malonyl-CoA decarboxylase activity.