Shinji Fushiya

Avenic acid, a new amino acid possessing an iron chelating activity

Abstract A new amino acid derivative possessing an iron chelating activity was isolated from root washings of water cultured Avena sativa under iron deficient conditions. The structure of this compound, avenic acid A has been determined as 2(S),3′(S),3″(S)-N-[3-(3-hydroxy-3-carboxypropylamino)-3-carboxypropyl]-homoserine (1) on the basis of chemical and spectroscopic evidence.

Biosynthesis of nicotianamine in the suspension-cultured cells of tobacco (Nicotiana megalosiphon)

SummarySeven kinds of suspension cell cultures from five species ofNicotiana were screened for the occurrence of nicotianamine. Nicotianamine was detected in the cultured cells ofN. megalosiphon andN. plumbaginifolia.l-[l-14C]Methionine, which is the precursor of the mugineic-acid-family phytosiderophores and nicotianamine in barley plants, was incorporated into nicotianamine by the cultured cells ofN. megalosiphon both in vivo and in vitro. The advantage of the cultured tobacco cells for the study of the biosynthesis of nicotianamine and the mugineic-acid-family phytosiderophores is discussed.

Co-occurrence of nicotianamine and avenic acids in Avena sativa and Oryza sativa

Abstract An amino acid derivative isolated from seedlings of Avena sativa and Oryza sativa , along with avenic acid A and its derivatives which possess a chelating ability with iron ions, has been shown to be nicotianamine. The co-occurrence of nicotianamine and avenic acids in the same plant, as well as their structural similarity, reveals their close biosynthetic relationship.

Acromelic acid C. A new toxic constituent of clitocybe acromelalga : An efficient isolation of acromelic acids

Abstract The neurotoxic amino acids, acromelic acids A and B were efficiently isolated from the poisonous mushroom Clitocybe acromelalga, accompanied by a new toxic analogue, acromelic acid C. The structure of acromelic acid C was elucidated to be 1 by comparison of the spectral data with those of acromelic acids A and B. Acromalic acid C exhibited a lethal toxicity to the mice at a dose of 10 mg/kg.

Isolation of acromelic acids D and E from Clitocybe acromelalga

Two analogs of acromelic acid were isolated from Clitocybe acromelalga. The structures of these compounds, acromelic acids D and E were determined to be 4 and 5, respectively by 1 H nmr analysis and by comparison of the spectral data with that of the synthetic one in the case of 4

Potentiation by febrifugine of host defense in mice against Plasmodium berghei NK65

The effect of febrifugine, the main alkaloidal constituent of an antimalarial crude drug, Dichroa febrifuga Lour., on protective immunity in mice infected with erythrocytic stage Plasmodium berghei NK65 was investigated. Febrifugine was administered orally, at a dose of 1 mg/kg/day, to mice before and/or after they were infected intraperitoneally with 2 x 10(6) parasitized red blood cells. Then, mortality and the levels of parasitemia and plasma NO3- [a degradation product of nitric oxide (NO)] were monitored. Febrifugine significantly reduced the mortality and the level of parasitemia. The plasma NO3- concentration began to rise within 2 days after treatment with febrifugine and declined to normal in 2 days when the mice were treated orally with febrifugine once a day for 3 consecutive days before parasite infection. This antimalarial activity of febrifugine was reduced by both N(G)-monomethyl-L-arginine and aminoguanidine. These results indicate that the increased production of NO by febrifugine plays an important role in host defense against malaria infection in mice.

Inductions of two enzyme activities involved in the biosynthesis of mugineic acid in Fe-deficient barley roots

The temporal changes in two enzyme activities involved in the biosynthesis of mugineic acid-family phytosiderophores are described. Both nicotianamine synthase and nicotianamine aminotransferase are significantly induced by Fe-deficiency treatment. It took less than one week to induce the activities in primary root tips of young barley plants. Although the amount of secreted MAs was changed drastically during the day, these enzyme activities did not show daily changes.

β-Cyano-l-alanine and N-(γ-l-glutamyl)-β-cyano-l-alanine, neurotoxic constituents of Clitocybe acromelalga

Abstract The neurolathyrogens, β-cyano-l-alanine and its γ-l-glutamyl peptide were isolated from a toxic mushroom, Clitocybe acromelalga, along with acromelic acids. The unique symptoms caused by ingestion of this mushroom might be attributed in part to these cyanogenic compounds from a consideration of their toxic properties.

Oral administration of Ren-Shen-Yang-Rong-Tang 'Ninjin'yoeito' protects against hematotoxicity and induces immature erythroid progenitor cells in 5-fluorouracil-induced anemia.

The purpose of this study was to investigate the efficacy of four different Japanese and Chinese herbal prescriptions, Ren-Shen-Yang-Rong-Tang (Ninjin’yoeito, NYT), Chai-Hu-Gui-Zhi-Gan-Jiang-Tang (Saikokeishikankyoto, SKKT), Si-Jun-Zi-Tang (Shikunshito, SKT) and Si-Wu-Tang (Shimotsuto, SMT), which are traditionally used for anemia and fatigue, against hematotoxicity in mice treated with 5-fluorouracil (5-FU). NYT 1–100 mg kg–1 day–1 injected orally for 7 consecutive days before and after 5-FU injection significantly suppressed reductions in red blood cell, white blood cell and platelet counts in peripheral blood, and accelerated their recovery. Administration of SKKT also produced a slight but significant improvement in 5-FU-induced erythrocytopenia, whereas SMT and SKT could not prevent anemia. Oral injection of NYT also inhibited 5-FU-induced decreases in peripheral reticulocyte and bone marrow cell counts on day 10, and markedly hastened their recovery on day 20, in a dose-dependent manner. Erythroid progenitor colonies, such as colony forming units-erythroid and burst forming units-erythroid, formed by marrow cells from mice treated with 5-FU were significantly increased by oral administration of NYT. These findings suggest that NYT has the potential to protect against hematotoxicity, and also has hematopoietic activity, through stimulation of immature erythroid progenitor cell differentiation.

Constituents of Rhodiola rosea showing inhibitory effect on lipase activity in mouse plasma and alimentary canal.

As a methanol extract of the rhizome of Rhodiola rosea inhibits the activity of lipase in isolated mouse plasma in vitro and in the mouse gastrointestinal tube in vivo, the active components in this plant were investigated. After fractionation and separation processes, rhodionin and rhodiosin were isolated as active ingredients. Their IC50 values were 0.093 mM and 0.133 mM in vitro, respectively. Both compounds significantly suppressed the elevation of the postprandial blood triglyceride level, e.g., by 45.6 % (150 mg/kg, 60 min after oral administration) and 57.6 % (200 mg/kg, 180 min after oral administration), respectively. Consequently, we anticipate the application of this plant and its constituents to the treatment of lifestyle-related diseases such as hyperlipidemia and exogeneous obesity and to health foods.