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Biomedical subjects

I Kitagawa

Publications and source records attributed to I Kitagawa.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Anti-tumor marine natural products].

In anticipation of developing new anti-cancer drugs from marine organisms of rich species, a variety of anti-tumor substances having diverse chemical structures have been discovered. Among those marine anti-tumor substances, which were reviewed in a previous paper [Jpn. J. Cancer Chemother., 16, 1-8 (1989)], several compounds promising as anti-cancer drugs are detailed in this article. They are didemnin B from marine tunicate, bryostatin 1 from marine bryozoa, and dolastatin 10 from sea hare. In addition, several anti-tumor marine sponge constituents: halichondrin B, calyculin A, and mycalamides A and B, are briefly reviewed.

Animals↗
PubMed1989

Araguspongines B, C, D, E, F, G, H, and J, new vasodilative bis-1-oxaquinolizidine alkaloids from an okinawan marine sponge, Xestospongia sp.

Nine new vasodilative alkaloids, araguspongines A, B (1), C (2), D (3), E (4), F (5), G (6), H (7), and J (8), were isolated from an Okinawan marine sponge, Xestospongia sp. On the basis of chemical and physicochemical evidence, the absolute stereostructures of araguspongines B, D, E, F, G, H, and J were determined respectively as 1, 3, 4, 5, 6, 7, 8, and the relative stereostructure of araguspongine C was determined as 2 having two 1-oxaquinolizidine moieties. Araguspongines B, D, and E each comprised a pair of the enantiomers, 1a and 1b, 3a and 3b, and 4a and 4b, respectively.

Alkaloids↗
PubMed1989

Ionophoretic activities of oligopeptide lactones and resin-glycosides in human erythrocytes.

Oligopeptide lactones (theonellapeptolides) isolated from the Okinawan marine sponge Theonella swinhoei and resin-glycosides (merremosides) from the tuber of an Indonesian medicinal plant Merremia mammosa were examined regarding their activities in transporting Na+, K+, and Ca++ ions into human erythrocytes. Each of these lactones, which had been shown, using a supported liquid membrane, to have an ionophoretic effect on the alkali metal ions, transported the ions to a different extent. The ion transporting activities of these compounds were completely lost when the macrocyclic lactone structures were cleaved by sodium methylate. Resin-glycosides with an additional branched glycosyl residue showed much greater ion transporting activities than those without it.

Erythrocytes↗
PubMed1989

[Anti-tumor natural products isolated from marine organisms].

Marine organisms comprise over half a million species. Due to their unusual living environment as compared with terrestrial organisms, marine organisms produce a variety of metabolic substances which often have various unprecedented chemical structures. In recent years, an increasing number of marine natural products have been reported to exhibit various biological activities such as antimicrobial, physiological, and pharmacological ones. Some metabolites have also been noted by their significant toxicities. The effort to find out anti-tumor substances from marine organisms has been also undertaken in recent years, and several novel compounds (e.g. peptide, polyether, alkaloid, prostanoid etc.), with anti-tumor activities, have been isolated from marine sponges, octocorals, marine algae, tunicates, nudibranchs, bryozoans, and so on. In this article, those chemically clarified anti-tumor compounds isolated from marine organisms were reviewed.

Animals↗
PubMed1988

Hypaconitine, the dominant constituent responsible for the neuromuscular blocking action of the Japanese-sino medicine "bushi" (aconite root).

The neuromuscular blocking actions of several constituents extracted from Japanese-sino medicine, aconite, were compared in mouse phrenic nerve-diaphragm muscle preparations. Hypaconitine (HAT) was more potent than aconitine (ATN), mesaconitine (MAT) and deoxyaconitine. Lipohypaconitine, coryneine and lipodeoxyaconitine were less effective. Lipoaconitine, benzoylmesaconine, higenamine, kobusine and chasmanine were not effective. The blockades by HAT, ATN and MAT were not recovered by neostigmine. The mechanisms of blockade were similar to that of aconite crude extract. These results suggest that aconite action is dependent on HAT, a main constituent.

Aconitine↗
PubMed1987

Plant-glycoside modulation of cell surface related to control of differentiation in cultured B16 melanoma cells.

We have shown that the ginsenosides Rh1 and Rh2, which are plant glycosides with a dammarane skeleton resembling a steroid skeleton as an aglycone, control the phenotypic expression of mouse B16 melanoma cells in different ways. The effects of Rh1 and Rh2 on the cell surface were studied to clarify the relationship between the control of phenotypic expression and modification of the cell surface in B16 melanoma cells. Rh2, which has the capacity to inhibit the growth of and to stimulate melanogenesis in B16 melanoma cells, causes flattening of the cells cultured in a collagen gel, leading to organized, nonoverlapping monolayers. Cell-to-cell adhesiveness and cell-to-substrate adhesiveness were markedly increased in the B16 melanoma cells treated with Rh2. In Rh2-treated cells, the binding of peanut agglutinin on the cell surface was also increased, whereas no marked changes were observed in the binding of concanavalin A or wheat germ agglutinin. In contrast, Rh1, which showed no effect on cell growth, but did stimulate melanogenesis, did not cause morphological changes of the cells and exerted no effect on cell adhesiveness or cell surface lectin binding. 1,6-Diphenyl-1,3,5-hexatriene polarization values markedly decreased in cells treated with either Rh1 or Rh2. Rh2 was found to be incorporated in the lipid fraction of the B16 melanoma cell membrane. In contrast, Rh1 was not detected in the lipid fraction of B16 melanoma cells. However, novel lipid components were found.

Agglutination↗
PubMed1986

Effect of soya saponins on gold thioglucose (GTG)-induced obesity in mice.

The effect of oral administration of total soya saponins (TS) on the development of obesity induced by (GTG) injection was examined. In the GTG-obese group, the serum immunoreactive insulin (IRI) levels were significantly increased and food consumption was suggestively increased. In addition, sucrase activity in the intestinal mucosa was increased and the surface area of intestinal villi was significantly greater, suggesting enhanced gastrointestinal function. Oral administration of TS prevented development of obesity and prevented an increased level of IRI in GTG-obese animals. It also restored the sucrase activity and the surface area of intestinal villi to normal. Thus, TS may be effective in preventing development of obesity.

Animals↗