Kenichiro Inoue

Simple compounds, 2-alkyl-2-amino-1,3-propanediols have potent immunosuppressive activity

Abstract ISP-I (myriocin, thermozymocidin) was structurally simplified to give 2-amino-2-alkyl-1,3-propanediols that were also potent immunosuppressants. Among the series, 2-amino-2-pentadecyl-1,3-propanediol most actively prolonged rat skin allograft survival and was more effective than ciclosporin.

Biosynthesis of shikonin in callus cultures of Lithospermum erythrorhizon

Abstract Administration of various supposed precursors to the callus cultures of Lithospermum erythrorhizon grown on the Linsmaier—Skoog medium supplemented with IAA and kinetin established that the constituent shikonin is formed via shikimic acid, p-hydroxybenzoic acid, m-geranyl-p-hydroxybenzoic acid and geranylhydroquinone. In a strain of callus culture lacking the capacity to synthesize shikonin and in callus cultures which have had this capacity but lost it due to cultivation on a medium supplemented with 2,4-D, substances up to m-geranyl-p-hydroxybenzoic acid in the biosynthetic sequence have been detected. Although illumination with white light also arrested shikonin production, traces of pigment were still formed presumably because light did not reach the innermost part of the callus cultures.

Biosynthesis of anthraquinones and related compounds in Galium mollugo cell suspension cultures

Abstract From Galium mollugo cell suspension cultures, 1,4-dihydroxy-3-prenyl-2-naphtholic acid methyl ester diglucoside was isolated along with anthraquinones and mollugin. Production of the diglucoside was much increased by administering 2-succinylbenzoate to the cultures. The incorporation of 2-succinylbenzoate into lucidin-3-primeveroside, mollugin and the diglucoside in the mode so far proposed for rubiaceous anthraquinones was verified by administration of 13C-labelled 2-succinylbenzoate to the cell cultures.

Anthraquinones in cell suspension cultures of Morinda citrifolia

Abstract From cell suspension cultures of Morinda citrifolia five known anthraquinones, rubiadin, lucidin, morindone, lucidin-3-β-primeveroside and morindone-6-β-primeveroside, and seven new anthraquinones were isolated. Six of the seven new quinones were characterized as 2-methyl-3,5,6-trihydroxyanthraquinone, 3-hydroxymorindone, 5,6-dihydroxylucidin, 2-methyl-3,5,6-trihydroxyanthraquinone-6-β-primeveroside, 3-hydroxymorindone-6-β-primeveroside and 5,6-dihydroxylucidin-3-β-primeveroside, respectively.

A naphthoquinone and a lignan from the wood of Kigelia pinnata

Abstract A new naphthoquinone, kigelinone, and a new lignan, kigeliol, together with six known constituents including lapachol and dehydro-α- lapachone, were isolated from the wood of Kigelia pinnata . On the basis of spectral data and chemical degradations, kigelinone was characterized as 2-(1-hydroxyethyl)-8-hydroxy-naphtho[2,3-b]furano-4,9-dione and kigeliol as (2 S ,6 S )-bis(3,4-methylenedioxyphenyl)- 3,7- dioxabicyclo[3.3.0]octan-1 R ,5 R -diol or its enantiomer.

A secoiridoid glucoside from Olea europaea

Abstract Besides two known glucosides, olcuropein and ligstroside, a new secoiridoid glucoside, oleuroside was isolated from Olea europaea and its structure

MONOTERPENOID AND PHENYLETHANOID GLYCOSIDES FROM LIGUSTRUM PEDUNCULARE

Two new phenylethanoid glycosides, lipedosides A-I and A-II as well as six new monoterpene glycosides, lipedosides B-I-B-VI were isolated together with three known constituents, osmanthuside B, anatolioside and linalool from Ligustrum pedunculare. Their structures have been elucidated by chemical and spectroscopic methods.

Quinones of streptocarpus dunnii

Abstract From the mature plants, plantlets and cultured cells coexisting with half differentiated plantlets of Streptocarpus dunnii , five unusually prenylated naphthoquinones and one anthraquinone were newly isolated along with both dunnione and 1-hydroxy-2-hydroxymethylanthraquinone, which had already been found in this plant. Furthermore, the structures of four new naphthoquinones, dehydrodunnione, streptocarpone, 7-hydroxydunnione and 8-hydroxydunnione, were elucidated. The optical purities of dunnione derivatives are discussed.

Two quinones from callus cultures of Echium lycopsis

Abstract Two new quinones, echinone and echinofuran, have been isolated from callus cultures of Echium lycopsis along with several acyl esters of shikonin. The structures of both quinones have been established by spectroscopic methods and by chemical degradations.

SECOIRIDOID, COUMARIN AND SECOIRIDOID-COUMARIN GLUCOSIDES FROM FRAXINUS-CHINENSIS

Besides the known glucosides, oleuropein, neooleuropein and cichoriin, a new secoiridoid glucoside, frachinoside, was isolated from the leaves of Fraxinus chinensis and its structure elucidated.