Two gossypetin methyl ethers as ultraviolet patterning guides in the flowers of Coronilla valentina

The 3′-monomethyl and 8,3′-dimethyl ethers of gossypetin have been identified in the flowers of Coronilla valentine where they occur as the 3-rutinosides. These two yellow flavonols occur specifically in the wings and thus provide both visible yellow colour and UV absorption to bees, which land on the wings and trigger the self-fertilization mechanism. These yellow pigments are absent from the flowers of the related C. emerus, where their role in UV patterning is taken over by colourless kaempferol and quercetin glycosides.     

Correlations between flavonoid chemistry,anatomy and geography in the restionaceae

Comparisons of the flavonoid patterns in stems and inflorescences between Australasian and South African members of the Restionaceae indicate significant differences with geography. Nine of 14 Australasian species contain gossypetin or a related 8-hydroxyflavonoid and proanthocyanidins are uncommon. By contrast, the 33 South African taxa studied contain common flavonols, flavones and glycoflavones, while proanthocyanidins are present in 29. Two anatomically related South African genera, Chondropetalum and Elegia, contain, in addition, myricetin 3-galactoside, together with the 3-galactosides of the myricetin methyl ethers, larycitrin and syringetin. These results confirm the conclusions derived from anatomy that members of Hypolaena, Leptocarpus and Restio, genera represented in both Australia and South Africa, have the distinctive flavonoids characteristic of their geographic origin rather than of their systematic position. The family as a whole is different in flavonoid pattern from other monocotyledonous families with which it is sometimes associated.     

重楼排草的化学成分研究

从报春花科植物重楼排草（L.Paridiformis Frach）的全株中分离得到了7个化合物。应用各种理化方法及光谱分析鉴定其化学结构。分别鉴定为：希克拉敏A-3-O-｜β-D-吡喃木糖基．（1→2）-β-D-吡喃葡萄糖基-（1→4）-[β-D-吡喃葡萄糖基-（1→2）]｜}-α-L-吡喃阿拉伯糖苷（1）、3β-O-[β-D-吡喃木糖基-（1→2）-β-D-吡喃葡萄糖基-（1→4）]。[β-D-吡喃葡萄糖基-（1→2）]-α-L-吡喃阿拉伯糖基-16α-羟基-13β,28-环氧-齐墩果烷（2）、异鼠李素-3-O-[β-D-吡喃鼠李糖基-（1→）β-D-吡喃阿拉伯糖苷]（3）、槲皮素-3-O-[β-D-吡喃鼠李基-（1→4）-β-D-吡喃阿拉伯糖苷]（4）、β-香树素（5）、β-香树素乙酸酯（6）、三十二烷醇（7）。其中1、2、3、4均为首次从本植物中分离得到。     

Influence of phosphatidylcholine/cholesterol molar ratios in liposomes on cholesterol reactivity with cholesterol:oxygen oxidoreductase]

The reactivity of sonicated phosphatidylcholine-cholesterol liposomes with cholesterol : oxygene oxydoreductase, an enzyme which catalyses the oxidation of the 3 beta hydroxyl group of cholesterol to a ketone group, is compared with that of ternary system phosphatidylcholine-cholesterol-Thesit. Regardless to the phosphatidylcholines nature and the phosphatidylcholine/cholesterol molar ratio (R), the enzymatic oxidation rate of liposomal cholesterol is slower than when the reaction is developed in the present of Thesit, a surfactif agent which destroyes the lamellar particles. This is true whether Thesit is added during preparation of dispersions or during incubation with cholesterol oxydase. The enzymatic oxydation rate of cholesterol of ternary systems phosphatidylcholine-cholesterol-Thesit is independent of the (R) value and the phosphatidylcholine fatty acid unsaturation, whereas that of phosphatidylcholine-cholesterol dispersions depends on these two parameters. The reaction rate increases in the order: dipalmitoylphosphatidylcholine to yolk egg phosphatidylcholines, and dioleylphosphatidylcholine. The optimal conditions for cholesterol oxidation were found to be R = 0.5. This result is not affected by the phosphatidylcholines nature. In order to explain these data, various hypotheses are considered. In particular, the weak liposomal cholesterol reactivity with cholesterol oxidase could result from an inhibitory effect on the enzyme-substrate combination due to the polar phosphorylcholine groups.     

半卧狗娃花中的黄酮类化合物

从半卧狗娃花(Heteropappus semiprost Griers)全草的乙醇提取物中分离并鉴定了7个黄酮类化合物,通过波谱分析及化学方法鉴定其结构为:3′,4′,5,7-四羟基黄酮(1),3′-甲氧基槲皮素(2),槲皮素-3-O-α-L-吡喃鼠李糖甙(3),槲皮素-3-O-β-D-吡喃半乳糖甙(4),异鼠李亭-3-O-β-D-吡喃半乳糖甙(5),槲皮素-3-O-α-L-吡喃鼠李糖(1→6)-β-D-吡喃葡萄糖甙(6),异鼠李亭-3-O-α-L-吡喃鼠李糖(1→6)-β-D-吡喃葡萄糖甙(7),其中化合物1~5为首次从本属植物中分离得到。     

Quercetin 3-(6″-caffeoylgalactoside) from Hydrocotyle sibthorpioides

In addition to quercetin, quercetin 3-galactoside and isorhamnetin, a new caffeoylgalactoside has been isolated from Hydrocotyle sibthorpioides and identified by chemical and spectral data as quercetin 3-O-β-d-(6″-caffeoylgalactoside).     

3,3′-di-O-Methylellagic acid 4-O-rhamnoside from the roots of Prosopis juliflora

From the roots of Prosopis juliflora a new glycoside, 3,3′-di-O-methylellagic acid 4-O-α-l-rhamnopyranoside, and procyanidin have been characterized.     

Biologically-active flavonoids from Gossypium arboreum

A new flavonol glycoside, gossypetin 8-O-rhamnoside, was isolated from flower petals of Gossypium arboreum along with quercetin 7-O-glucoside, quercetin 3-O-glucoside and quercetin 3′-O-glucoside. These compounds showed antibacterial activity against Pseudomonas maltophilia and Enterobacter cloacae.     

An approach to the chemosystematics of the zygophyllaceae

The Zygophyllaceae occur in arid zones and have been reported to contain, among other compounds, flavonoids and alkaloids. The flavonoids in representatives of three of the seven subfamilies have been studied and their distribution is discussed with respect to their chemosystematic significance. The aglycones identified were kaempferol, quercetin, isorhamnetin, herbacetin and herbacetin-8-O-methyl ether. Glycosidic patterns elucidated range from mono- to tri-glycosides, five of which are novel in plants. Alkaloids were also shown to be present, and the importance of those cited in the literature has been surveyed in relation to the chemosystematics of the Zygophyllaceae.     

Flavonoids from Rhamnus pallasii

A new dihydroflavonol, pallasiin, together with kaempferol, quercetin, isorhamnetin, mearnsetin, aromadendrin, eriodictyol and taxifolin, has been isolated from the bark of Rhamnus pallasii and its structure elucidated as 2,3-dihydromyricetin 4′-O-methyl ether.     

Distribution of charged flavones and caffeylshikimic acid in Palmae

Identification of the phenolic constituents in flowers of nine palm species has revealed that charged C-glycosylflavones and caffeylshikimic acid are characteristically present. Flavonol glycosides are also common; the 3-glucosides, 3-rutinosides and 3,4′-diglucosides of quercetin and isorhamnetin and the 7-glucoside and 3,7-diglucoside of quercetin are all variously present. Tricin 7-glucoside, luteolin 7-rutinoside and several unchanged C-glycosylflavones were also detected. Male flowers of Phoenix canariensis differ from female flowers in having flavonol glycosides. As expected, in most species studied, flavonoid patterns in the flowers vary considerably from those found in the leaves.     

Isorhamnetin 3,7-disulphate from Flaveria bidentis

3-Glucosides and 3,5-diglucosides of pelargonidin, cyanidin, peonidin, delphinidin, petunidin and malvidin have been identified as flower pigments in Fuchsia species. These pigments in varying admixture appear to be solely responsible for different flower colours in this genus. Their production and inheritance seems to be under a complex system of genetic control.