Astringent tannins of Acer species

All 25 species of Acer examined contain condensed (proanthocyanidins) and hydrolysable (gallo- and/or ellagi-) tannins, but each of these varies ov     

Astringent tannins of the leaves of Geranium species

Fifty per cent methanolic extracts of the leaves of 70 species (including some subspecies, varieties and one hybrid) of Geratiium have been analysed for proanthoeyanidins, total galloyl esters, hexahydroxydiphenoylglucose and astringency. Proanthoeyanidins are present in most species (prodelphinidin in four) but only rarely in considerable quantities and then not readily extracted. A reaction with potassium iodate characteristic of geraniin (a derivative of dihexahydroxydiphenoylglucose) is given by most species. The very considerable differences in astringency between species cannot at present be accounted for in terms of chemical differences, but a systematic review suggests that geographical location, chromosome number and annual or biennial habit are involved in the amount ofiannin present in particular species.     

Astringent tannins of Viburnum and Hydrangea species

The tannins of the leaves of Viburnum and Hydrangea species consist of proanthocyanidins only, but in each genus the range is very wide. In several species of Hydrangea the proanthocyanidins are of the A type, otherwise they are mostly tri- or tetrameric B type. Tannin content is correlated with evolutionary advancement, the more advanced and more widely dispersed species having the less. Species with most tannin occur in E. Asia and E. N. America, but species with little or no tannin are present in both areas. The occurrence in both genera of globose inflorescences with sterile flowers is correlated neither with morphological nor with chemical characters.     

Haemanalysis of tannins: The concept of relative astringency

The astringency of tannins, that is their efficiency as precipitants of proteins, is determined by their reaction with the proteins of haemolysed blood and calorimetric determination of residual haemoglobin. The method is accurate and sensitive because of the narrow range of concentration of tannin between that required to initiate precipitation (the threshold concentration) and that for complete precipitation. ‘Relative astringency’ (RA) is the ratio of the concentration of the tannic acid to that of the tannin which effects the same degree of precipitation. The RA of certain esters of hexahydroxydiphenic acid and of certain procyanidins of known constitution has been determined and the results applied to the ellagitannins and/or leucoanthocyanins present in species of Shorea, Geranium and other plants. The homology of each of these classes of tannins is discussed in the light of the results.     

中国无患子科植物的叶脉形态及其系统学意义

对国产狭义无患子科25属27种植物的叶脉形态特征进行了研究报道。结果表明：叶脉均属于羽状脉类型,其中多数为曲行羽状脉,部分为直行羽状脉;叶缘有全缘、具齿和深裂3种类型;二级叶脉具有分支和不分支两种类型;大部分种类具二级间脉,少数不具间脉或间脉不明显;多数种类的三级脉为结网型和贯串型并存;网眼的发育有完善和不完善2种类型;盲脉有简单、具分支和无盲脉3种类型。叶脉形态研究结果支持文冠果亚科以及广义鳞花木属概念,观察发现龙眼属、荔枝属与韶子属从脉序特征方面表现出较近的亲缘关系。编写了国产无患子科叶片脉序特征检索表。     

Leaf Venation and Its Systematic Significance in Sapindaceae of China

Leaf venation of 27 species representing 25 genera of Sapindaceae (sstr.) of China was investigated for the first time. The pinnate venation pattern in most species is either camptodromous, or craspedodromous. Three types of leaf blade margin were observed, ie., entire, toothed and partite. The secondary veins are branched or unbranched. Most species have intersecondary veins. The tertiary veins of most species are reticulate and percurrent. The areoles are regular or irregular. Veinlets are simple, branched or absent. The delimitations of Xanthoceroideae and Lepisanthes sensu lato are supported by leaf venation characters. The close relationships among Dimocarpus, Litchi and Nephelium are supported by the evidence from leaf venation. A key to the species of Sapinaceae based on leaf venation characters is presented.     

The utility of leaf flavonoids as taxonomic markers for some Malaysian species of the tribe Shoreae (Dipterocarpaceae)

A flavonoid survey was carried out on 45 taxa from the genera Shorea, Hopea, Parashorea, Neobalanocarpus, and Dryobalanops of the tribe Shoreae in the Dipterocarpaceae. The study showed significant chemotaxonomic differences in leaf flavonoid aglycone patterns and the presence of tannins in these taxa. The flavonoid patterns are useful in the delimitation of some taxa. For example, the genus Parashorea is distinguished by the universal presence of kaempferol 3‐methyl ether, and the monotypic genus Neobalanocarpus is unique in not producing ellagic and gallo tannins. The presence of chalcones and flavone C‐glycosides supports the separation of the genus Hopea into two sections, section Dryobalanoides and section Hopea in Ashton's classification, which is based on the type of venation. The flavonoid distributions in this study show that they can be very useful for differentiating between the Balau group in the genus Shorea and some scaly barked Hopea species, particularly H. helferi (lintah bukit), H. nutans (giam), and H. ferrea (malut). © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 755–762.     

The condensed tannins of pasture legume species

Condensed tannins have been isolated from legume pasture species and purified by gel chromatography on Sephadex G-50 and LH-20 media. Molecular size di     

A new flavonoid from the stem bark of Acer tegmentosum

A new flavonoid, 6-carboxyl-(−)-catechin methyl ester (1) was isolated from the stem bark of Acer tegmentosum, along with six known flavonoids (2–7). The structure of compound 1 was determined by spectral analyses, including HR-ESI-MS, 1D and 2D NMR (COSY, HMQC and HMBC) experiments. From present investigation, compound 7 was isolated for the first time from the Aceraceae family.     

Chemical constituents from the stem bark of Acer tegmentosum

A new phenolic glycoside, 4-hydroxyphenylethyl-1-O-β-D-[6′-O-(4-hydroxybenzoyl)]-glucopyranoside (1) was isolated from the stem bark of Acer tegmentosum, along with seven known phenolic compounds (2–8). The structure of compound 1 was determined by spectral analyses, including HR-ESI-MS, 1D and 2D NMR (COSY, HMQC and HMBC) experiments. Compounds 3 and 4 were found in the family Aceraceae for the first time.     

中国槭树科二新记录种

三裂枫Acer calcratum Gagnep．和长裂枫Acer acuminatum Wall．exD．Don两种分布于东南亚和喜马拉雅地区的珍稀树种,最近分别发现在我国云南和西藏有分布,属于我国新记录种。三裂枫属于广义鸡爪槭组sect．Palmata中华槭系ser．Sinensia,主要形态特点为叶片三裂,叶片基部圆形,伞房花序,通常只有一个发育完全的果实,坚果近卵球形。长裂枫属于尖齿槭组sect．Arguta,主要特点为叶片3裂和5裂,侧裂片和中央裂片近等长,裂片先端长渐尖,花序长达12-20cm。     

Chemistry and taxonomy of the cunoniaceae

The inclusion of the Cunoniaceae within a rosalean alliance is unquestioned, but its position in such an alliance is uncertain. In respect of proanthocyanidins, flavonols, ellagitannins and absence of iridoids the most closely similar taxa are Saxifragaceae-Saxifragoideae and Rosaceae-Rosoideae, but in their xerophytic, arborescent habit and present and past southern hemisphere distribution the Cunoniaceae are very different from either. In these (but not in chemical) respects an analogy can be found in the Proteaceae, and a detached position similar to that assigned to this family in Dahlgren's system seems appropriate for the Cunoniaceae.     

Flavonoids of three local Senecio species

Two isorhamnetin glycosides and two sulphated derivatives are reported for the first time in the genus Senecio.     

The systematic distribution of tannins in the leaves of angiosperms: A tool for ecological studies

The systematic distribution of tannins in foliar tissues has not been comprehensively reviewed for the Angiosperms in over 20 years. Here their systematic distribution is assessed using data based on protein precipitation or chemically specific tests. Fewer families are characterized by the typical presence of tannins than has previously been reported, and a greater variation in the occurrence of tannins in species sampled from within single plant families has been detected. This study presents the proportion of tannin-containing species in angiosperm families arranged according to the system of Cronquist for the first time. The potential utility of these data in testing ecological ideas about the distribution of tannins, such as those based on plant habit or life-history, is discussed.     

槭属的系统演化与地理分布

槭属（ＡｃｅｒＬ）属槭树科（Ａｃｅｒａｃｅａｅ）,２００种,分布于亚、欧、北美和非洲北缘。本文研究了槭属的系统演化、地理分布、起源与扩散。认为：（１）槭树科与无患子科关系密切,槭属是槭树科２属中较进化的类群。（２）在原始而典型的槭属植物的基础上,槭属沿花的各部减少,有的器官甚至向完全退化的方向演化,但也有少数向增加数目的方向特化。（３）讨论了槭属４亚属２３组的演化趋势,并绘制出其系统演化图。（４）槭属起源于侏罗纪的中国四川东部、湖北、湖南及其邻近地区,并向西、东北和南方扩散而进入西亚、欧洲、非洲北缘、北美洲和马来半岛至印尼。     

Hydroxytropane tiglates in the roots of Mandragora species

Roots of Mandragora autumnalis and M. vernalis contain hyoscyamine, hyoscine, cuscohygrine, apoatropine 3α-tigloyloxytropane and 3,6-ditigloyloxytropane. Belladonnine is present in the dried roots but could not be detected in fresh roots. No major differences were found in the alkaloids present in the two species. This is the first time the presence of tiglic acid esters has been reported in Mandragora species and the significance of this in the chemotaxonomy of the genus is indicated.     

Preferential transport activity of DkDTX5/MATE5 affects the formation of different astringency in persimmon

Proanthocyanidins(PAs) are specialized metabolites that infuence persimmon fruit quality.Normal astringent(A)-type and non-astringent(NA)-type mutants show significant variation in PA accumulation, but the infuencing mechanism remains unclear. In this study, among the six identified DTXs/MATEs proteins associated with PA accumulation, we observed that allelic variation and preferential transport by Dk DTX5/MATE5 induced variation in PA accumulation for A-type and NA-type fruit. The expression pa...     

The tannosome is an organelle forming condensed tannins in the chlorophyllous organs of Tracheophyta

Background and Aims

Condensed tannins (also called proanthocyanidins) are widespread polymers of catechins and are essential for the defence mechanisms of vascular plants (Tracheophyta). A large body of evidence argues for the synthesis of monomeric epicatechin on the cytosolic face of the endoplasmic reticulum and its transport to the vacuole, although the site of its polymerization into tannins remains to be elucidated. The aim of the study was to re-examine the cellular frame of tannin polymerization in various representatives of the Tracheophyta.

Methods

Light microscopy epifluorescence, confocal microscopy, transmission electron microscopy (TEM), chemical analysis of tannins following cell fractionation, and immunocytochemistry were used as independent methods on tannin-rich samples from various organs from Cycadophyta, Ginkgophyta, Equisetophyta, Pteridophyta, Coniferophyta and Magnoliophyta. Tissues were fixed in a caffeine–glutaraldehyde mixture and examined by TEM. Other fresh samples were incubated with primary antibodies against proteins from both chloroplastic envelopes and a thylakoidal chlorophyll-carrying protein; they were also incubated with gelatin–Oregon Green, a fluorescent marker of condensed tannins. Coupled spectral analyses of chlorophyll and tannins were carried out by confocal microscopy on fresh tissues and tannin-rich accretions obtained through cell fractionation; chemical analyses of tannins and chlorophylls were also performed on the accretions.

Key Results and Conclusions

The presence of the three different chloroplast membranes inside vacuolar accretions that constitute the typical form of tannin storage in vascular plants was established in fresh tissues as well as in purified organelles, using several independent methods. Tannins are polymerized in a new chloroplast-derived organelle, the tannosome. These are formed by pearling of the thylakoids into 30 nm spheres, which are then encapsulated in a tannosome shuttle formed by budding from the chloroplast and bound by a membrane resulting from the fusion of both chloroplast envelopes. The shuttle conveys numerous tannosomes through the cytoplasm towards the vacuole in which it is then incorporated by invagination of the tonoplast. Finally, shuttles bound by a portion of tonoplast aggregate into tannin accretions which are stored in the vacuole. Polymerization of tannins occurs inside the tannosome regardless of the compartment being crossed. A complete sequence of events apparently valid in all studied Tracheophyta is described.