Noboru Otake

13C-NMR evidence for the pathway of chlorophyll biosynthesis in green algae

Abstract Analysis of the 13C-NMR spectra of chlorophyll enriched by feeding [1-13C]glutamate or [2-13C]glycine to a green alga, Scenedesmus obliquus , showed that 13C of the glutamate was incorporated in eight carbon atoms in a tetrapyrrole macrocycle derived from C-5 of 5-aminolevulinic acid (ALA), while 13C of glycine was in the methoxyl group adjacent to the isocyclic ring. A reversion was proposed in assignment of 13C chemical shifts of quaternary carbon in chlorophyll a .

The structures of novel nucleoside antibiotics, miharamycin A and miharamycin B

Abstract Based on 13 C- and 1 H-NMR spectral analysis the structures of miharamycins A and B have been determined to be novel 9-substituted 2-aminopurine nucleoside antibiotics as shown in Fig. 3.

Studies on the biosynthesis of bialaphos (SF-1293) Part 3. Production of phosphinic acid derivatives, MP-103, MP-104 and MP-105, by a blocked mutant of Streptomyceshygroscopicus SF-1293 and their roles in the biosynthesis of bialaphos

During biosynthetic studies on bialaphos to reveal the formation mechanisms of carbon-phosphorous bonds in detail, three new metabolites containing a H-P-C bond structure were isolated from the fermentation broth of a mutant of Streptomyces hygroscopicus SF-1293. Based on the spectroscopic analysis, the structures of these compounds have been determined as shown in Fig. 1. Transformation experiments of these metabolites to bialaphos suggested that the reduction of the phosphorous atom in phosphate will take place at an early biosynthetic stage.

The structure of a new nucleoside antibiotic, capuramycin

Summary The structure of capuramycin has been determined to be an uracil nucleoside with a caprolactam substituent as shown in Fig. 5 by NMR spectral analysis, chemical degradation and X-ray analysis.

Assamicin I and II, Novel Triterpenoid Saponins with Insulin-Like Activity from Aesculus assamica Griff.

Two novel triterpenoid saponins with insulin-like activity, termed assamicin I and II, were isolated from the roots of Aesculus assamica Griff. and their structures were characterized as 1 and 2, respectively. They inhibited release of free fatty acids from epinephrine-treated rat adipocytes and enhanced glucose uptake into 3T3-L1 adipocytes.

Application of long range j c-h resolved 2d spectroscopy (lrjr) in structural elucidation of natural products. The structure of oxirapentyn

Abstract The structure of a fungal metabolite, oxyrapentyn has been determined as shown in Fig. 7 by application of a new NMR technique, long range J C-H resolved 2D spectroscopy (LRJR).

ARUGOMYCIN, A NEW ANTHRACYCLINE ANTIBIOTIC

Biological activities of arugomycin and its analogues obtained by chemical degradation and modification were evaluated. Differences in the sugar moieties affected their biological activities including induction of differentiation of mouse Friend erythroleukemia cells and mouse myeloid leukemia cells, antitumor activities against sarcoma S-180, Ehrlich ascites carcinoma and P388 leukemia, and cytotoxicity against murine leukemia cells. Some relationships were found between the sugar moieties and biological activities.

Spicamycin, a New Differentiation Inducer of Mouse Myeloid Leukemia Cells (Ml) and Human Promyelocytic Leukemia Cells (HL-60)

A new antibiotic was obtained from the culture broth of Streptomyces alanosinicus 879-MT3, and the name spicamycin was given. Spicamycin had a marked effect on the induction of differentiation of human promyelocytic leukemia cells (HL-60) as well as mouse myeloid leukemia cells (Ml). Its structure was elucidated by degradative studies and 1H and 13C NMR spectral analysis as shown in Fig. 1.

The structure of a new antibiotic, chromoxymycin

Abstract Based on 1 H- and 13 C-NMR spectral data, the planar structure of chromoxymycin, a new antitumor antibiotic, has been determined as shown in Fig. 1.

Inhibitory effect of a spicamycin derivative, KRN5500, on the growth of hepatic metastasis of human colon cancer-producing tissue polypeptide antigen

Abstract The inhibitory effect of KRN5500, a spicamycin derivative, on the growth of hepatic metastasis of the tissue polypeptide antigen (TPA)-producing human colon cancer COL-1 was examined in severe combined immunodeficient (SCID) mice. Prior to this chemotherapeutic study, we confirmed the high correlation coefficient (r=0.86, P<0.01) between plasma TPA levels in athymic nude mice bearing COL-1 and tumor volume. In the chemotherapy of experimental hepatic metastasis induced by intrasplenic injection of COL-1 cells, KRN5500 at 12 mg/kg per day was administered i.v. three times at 4-day intervals. From the start of chemotherapy (day 1), plasma TPA levels in the mice were significantly decreased from 8332 U/l to a minimum of 494 U/l on day 16 and were within the range for intact SCID mice (409–634 U/l). The mean tumor weight was 4.87 g in the liver of untreated mice on day 19 and 0.74 g, in the liver of KRN5500-treated mice, a significant difference, representing a tumor growth inhibition rate of 85%. These results suggest the usefulness of TPA as a tumor marker in an experimental xenograft model. The chemotherapeutic efficacy of KRN5500 against experimental hepatic metastasis indicates that it may be a useful drug for the treatment of patients with hepatic metastases of colon cancer.