Kazufumi Yazaki

Ellagitannins of the casuarinaceae, stachyuraceae and myrtaceae

Abstract Eight ellagitannins and related polyphenols, found in Casuarina stricta and Stachyurus praecox , were detected in the leaf of Psidium species. Five of them and a new polyphenol, named isostrictinin, were isolated from Psidium guajava . Most of these compounds were detected in several species of Myrtaceae, and 2, 3-hexahydroxydiphenoylglucose and 4, 6-hexahydroxydiphenoylglucose were found in some.

Chromatography of tannins : II. Preparative fractionation of hydrolyzable tannins by centrifugal partition chromatography

Abstract Centrifugal partition chromatography with an apparatus which employs rotary joints has been applied to the separation of tannins in extracts from several plant species. The results were compared with those obtainable by droplet counter-current chromatography. Combined applications of normal- and reversed-phase developments, and of centrifugal partition chromatography and other chromatographic methods, were also carried out. The results show that centrifugal partition chromatography shortens the development time to a quarter of that with droplet counter-current chromatography, and enables separation of some tannins whose isolation by droplet counter-current chromatography is impracticable. It is also demonstrated that centrifugal partition chromatography is a suitable method, particularly on the preparative scale, for the separation of tannins.

Oenothein B, a dimeric, hydrolysable tannin with macrocyclic structure, and accompanying tannins from Oenothera erythrosepala

A new dimeric, hydrolysable tannin which we have named oenothein B (1), and eight accompanying compounds, including oenothein C (2), were isolated from the leaves of Oenothera erythrosepala. The macrocyclic structure of compound (1) was established from chemical and spectroscopic data. The previously assigned structure of compound (2) was also confirmed by two-dimensional NMR spectroscopy.

TANNIN PRODUCTION IN CELL SUSPENSION CULTURES OF GERANIUM THUNBERGII

Abstract Cell suspension cultures of Geranium thunbergii produced (+)-catechin, procyanidin B3, pentagalloylglucose, and phyllanthusiin D which is not found in the intact plant. Geraniin, the main tannin in the intact plant, was detected in the cells of a different strain of this culture.

Condensed tannin production in callus and suspension cultures of Cinnamomum cassia

Abstract Callus and suspension cultures of Cinnamomum cassia were found to produce a large amount of condensed tannin. ( − )-Epicatechin and procyanidins B2, B4 and C1 which are precursors of condensed tannin were isolated from callus cultures. Tannin production in callus cultures was stimulated by coconut milk or malt extract supplemented in the medium. In suspension cultures, cell growth in Linsmaier—Skoogs medium containing coconut milk was better than that in the absence of coconut milk. The time-course of cell growth and tannin content showed that the production of procyanidin dimer increased in the long lag phase of callus cultures.

Galloylhomoarbutin and related polyphenols from Pyrola incarnata

Abstract A new polyphenol, 6-O-galloylhomoarbutin was isolated from Pyrola incarnata, along with (+)-catechin, (−)-epicatechin gallate, procyanidin B1, B3 B2-3′-O-gallate, B2-3,3′-di-O-gallate, hyperin and hyperin-2″-O-gallate. Hyperin-2″-O-gallate, one of the main components, showed strong tanning activity.

Ellagitannin formation in callus cultures of Heterocentron roseum

Abstract Callus cultures of Heterocentron roseum, under illumination with fluorescent lamps, produced a large amount of casuarictin, an ellagitannin monomer. Nobotanin B, a dimeric ellagitannin, was also produced by the callus cultures. Illumination with light was required for both cell growth and ellagitannin production. Shoots which were redifferentiated from callus tissues contained larger amounts of casuarictin and nobotanin B than the callus cultures. The content of casuarictin was higher than that in intact leaves. The ellagitannin content in the callus cultures remained constant during the normal culture period.

Hydrolyzable tannins having a depsidone-forming valoneoyl group

The orientation of the valoneoyl group in praecoxins C and D as in the structures of praecoxins C and D was unequivocally proved by the 1 H- 13 C long-range shift correlation spectrum of rugosin C which was chemically correlated with praecoxin C

Constituents of Geranium thunbergii Sieb. et Zucc. Part 14. Structures of didehydrogeraniin, furosinin, and furosin

Three novel tannins, dehydrogeraniin, furosinin, and furosin, members of the dehydroellagitannins, were isolated from the aerial part of Geranium thunbergii Sieb. et Zucc., and their structures were elucidated on the basis of spectral evidence and chemical reactions. Dehydrogeraniin and furosinin were found to form equilibrium mixtures composed of four and eight tautomers, respectively, due to the equilibration of two dehydrohexahydroxydiphenoyl groups and the anomerization of the glucose moiety in the latter compound.