Evaluation of antioxidant and inhibitory activities for different subclasses flavonoids on enzymes for rheumatoid arthritis

Antioxidant activities of flavonoids were decreased in the order of flavonols > flavanones > flavones. Inhibitory intensities for hyaluronidase and collagenase reaction differed clearly according to flavonoid subclasses. Kaempferol, quercetin, myricetin, and rutin in flavonols inhibited hyaluronidase reaction specifically, while apigenin, luteolin, baicalin, and baicalein in flavones showed specific inhibition to collagenase reaction. In addition, the flavonoids, except baicalin and catechin, inhibited potently LPS-induced nitrite production in a dose-dependent manner, which might be mainly due to the suppression of inducible nitric oxide (NO) synthase. Quercetin and luteolin showed the strongest inhibitory activities on 15-lipoxygenase (LOX), and quercetin showed relatively potent inhibition on cyclooxygenase-1 (COX-1) reaction. Otherwise, all tested flavonoids possessed the inhibitory activity to COX-2 reaction, and especially luteolin, kaempferol, hesperetin, and naringin showed relatively the potent inhibition on COX-2 reaction. This report elucidated the anti-inflammatory activities, such as the antioxidant property, inhibition of NO production, and inhibition of inflammatory enzymes (hyaluronidase, collagenase, LOX, and COXs) of several subclass flavonoids.     

Phenols,proanthocyanidins, flavones and flavonols in some plant materials and their antioxidant activities

Methanol extracts prepared from five plant materials native to the Mediterranean area, namely olive tree (Olea europaea) leaf, St. John's wort (Hypericum perforatum), hawthorn (Crataegus laevigata), oregano (Origanum vulgare) and laurel leaf (Lauris nobilis), were examined for their phenolic components. Total phenolic content was determined by the Folin–Ciocalteu method. The content of proanthocyanidins in acid-hydrolysed extracts was determined spectrophotometrically. The contents of free flavones (apigenin and luteolin) and flavonols (kaempferol, myricetin and quercetin) were determined by HPLC analysis. The time of hydrolysis of flavones, flavonols and proanthocyanidins was optimised.Antioxidant activities of apigenin, luteolin, kaempferol, myricetin, quercetin and of plant extracts were examined. Antioxidative activities were studied in sunflower oil at 98 °C, by measuring peroxide value, and in an aqueous emulsion system of β-carotene and linoleic acid by measuring the absorbance of the sample. Among flavones and flavonols investigated, only myricetin inhibited oxidation of sunflower oil. All other flavones and flavonols showed pro-oxidative activity. Oppositely, in the emulsion system, only apigenin showed pro-oxidative activity while other flavones and flavonols and plant extracts inhibited oxidation of β-carotene.     

The flavone,flavonol and flavan-3-ol content of the Greek traditional diet

Flavonoids are an important category of plant antioxidants and evidence is accumulating on their favorable effects against the development of heart disease and certain forms of cancer. We analytically determined the flavonol (quercetin, kaempferol, myricetin, isorhamnetin), flavone (luteolin, apigenin) and flavan-3-ol (catechin, epicatechin, epigallocatechin, epigallocatechin gallate, epicatechin gallate) content of a weekly menu representative of the Greek traditional diet. The overall daily average content was found 79.01 mg of which flavonols contribute 47% (37.17 mg/day), flavan-3-ols 40% (31.67 mg/day) and flavones 13% (10.17 mg/day). The levels of agreement between the analytical results and the respective theoretical flavonoid calculations conducted previously on the same weekly menu ranged widely, indicating that caution should be taken when calculated flavonoid values are to be used in epidemiological studies. Compared to northern European and American diets, the traditional Greek diet has a higher flavonoid content, at least with respect to flavones, flavonols and flavan-3-ols.     

Determination of red wine flavonoids by HPLC and effect of aging

A new method for simultaneous determination of 10 flavonols and 2 flavones by high performance liquid chromatography was developed in this paper. The identified compounds contained quercetin, kaempferol, myricetin, rhamnetin, isorhamnetin, quercetrin, rutin, morin, galangin, fisetin, apigenin and luteolin. The chromatographic separation of these flavonoids was performed in a single run by using the mobile phase gradient elution of acetonitrile–methanol–water mixture (1% tetrahydrofuran, THF) at 20 °C, with the flow rate at 1.0 ml/min and the detection wavelength at 360 nm. With direct injection of wine samples, seven red wine samples, differing in their origin of producing places and time, were analyzed for flavonoids content by this method. The results showed the presence of myricetin, luteolin, quercetin, kaempferol, isorhamnetin and galanin. Additionally, the changes of flavonoids in red wines stored in the three types of oak barrels with aging time were investigated, which indicated that the component of flavonoids in red wine is related to wine aging greatly. These provide a substantial basis for the further research on control of flavonoids during winemaking.     

Changes of flavonol synthase and flavonol contents during grape berry development

Flavonols as an important kind of flavonoids not only have many defense-related functions, but also play an important role as potent antioxidants. Flavonol synthase (FLS) as the key enzyme in flavonol synthesis determines the final contents of flavonols in plant materials. The objective of this work was to study the changes of total flavonol content, free flavonol content, the individual flavonol aglycone contents and the two flavones (luteolin and apigenin) contents during grape berry development. The activity and the amount of the changes of FLS during grape berry development were also estimated. The results showed that quercetin, myricetin, kaempferol, isorhamnetin and galangin were detectable during grape berry development, and quercetin aglycone predominated in the total flavonol content in rapid growth phase, lag growth phase and the latter part of the ripening phase, myricetin aglycone witnessed a great increase at veraison, although kaempferol, isorhamnetin and galangin only accounted for a little part of the total flavonol contents but their individual contents all increased after veraison and kaempferol witnessed its highest content at the ripening phase. When it came to the contents of total phenols, total flavonoids, total flavonols and free flavonols, all of them showed accumulated peaks at both the rapid growth phase and the ripening phase. The result of FLS activity had a highly positive correlation with the total contents of flavonols, and the immunoblotting analysis detected two proteins whose signal intensities were in accordance with the FLS activities.     

Flavonols and flavones of parsley cell suspension culture change the antioxidative capacity of plasma in rats

The flavonoid aglycones from an illuminated parsley (Petroselinum crispum (Mill.) Nym.) cell suspension culture were identified and quantified as the flavones apigenin, luteolin and chrysoeriol and the flavonols kaempferol, quercetin and isorhamnetin. Flavonoid extracts from these cultures were purified by solid phase extraction from RP C-18 phase and given by gavage to rats. Only extract from illuminated culture increased the antioxidative capacity (AOC) of blood plasma temporarily with maximum values after 1 h. It is concluded that the course of AOC reflects changes in the plasma content of flavonoids.     

北京市售30种蔬菜中类黄酮物质含量分析

目的测定北京地区30种蔬菜中5种类黄酮物质的含量。方法采用高效液相色谱法检测槲皮素、山奈酚、杨梅黄酮、木犀草素、芹菜配基类黄酮物质的含量,蔬菜样品均购自北京当地菜市场。结果30种蔬菜中全部检出了槲皮素,含量在2.1～85.9mg/kg鲜重,9种蔬菜检出杨梅黄酮,8种蔬菜检出芹菜配基,8种蔬菜检出木犀草素,仅在胡萝卜和西红柿中检出山奈酚。紫洋葱、白洋葱、胡萝卜、甜椒和苦瓜等蔬菜类黄酮含量较高。结论不同蔬菜类黄酮物质的组成和含量差别较大,槲皮素为蔬菜中主要的类黄酮物质。     

Aglycone and glycoside specificity of apple skin flavonoid glycosyltransferase

O-Glycosyltransferase(s) extracted from apple (Malus pumila Mill) fruit skin showed activity towards a range of flavonols and anthocyanins. However, no glycosylating activity was shown towards a dihyroflavonol (dihydroquercetin), a flavanone (eriodictyol) or a flavone (luteolin). The enzyme preparation glycosylated those flavonoids normally present in apple skins (quercetin and cyanidin) and in addition several other related compounds (delphinidin, fisetin, isorhamnetin, kaempferol, myricetin and pelargonidin). This enzyme(s) specifically transferred the glycosyl moiety from sugar nucleotide donors to the 3-position of the flavonoid nucleus. Only flavonoid 3-glycosides occur naturally in apple skin. Activity with different sugar donors was in the order galactose>glucose>xylose, which reflected the ratios of cyanidin and quercetin glycosides found in apple fruit skin. There were slight differences in the relative UFGT activity with quercetin and the three different sugar donors between ‘Granny Smith’ and ‘Splendour’, and this was reflected by similar differences in the ratios of endogenous quercetin glycosides. ©1997 SCI     

四种黄酮类化合物与DNA相互作用关系研究

本实验分别从紫外吸收、热变性、结合平衡三个方面研究了四种黄酮类化合物桑色素、山萘酚、槲皮素和杨梅素与鲱鱼精DNA的相互作用。紫外吸收光谱表明:这四种黄酮化合物与DNA作用后,均导致DNA的最大吸收峰发生增色效应,桑色素和山萘酚使最大吸收峰红移,而槲皮素或杨梅素则使最大吸收峰发生蓝移。采用双倒数法,测得四种黄酮化合物与DNA作用的结合常数。通过热变性实验发现,四种黄酮化合物均使DNA的熔解行为发生变化。     

Evaluation of Aluminium Complexation Reaction for Flavonoid Content Assay

Two widely applied spectrophotometric assays based on aluminium complex formation used for determination of total flavonoid content in food or medicinal plant samples were examined for several compounds from different classes of flavonoid family. The method which involves the measurement at 410–430 nm after addition of AlCl₃ solution is selective only for flavonols and flavones luteolin. The procedure in the presence of NaNO₂ in alkaline medium seems to be specific for rutin, luteolin and catechins, but also phenolic acids exhibit considerable absorbance at 510 nm. Application of both procedures to natural samples gave different order in terms of their flavonoid content. Thus, the expression “total flavonoid” content is not adequate as the results of both methods are dependent on the structure of the individual flavonoids present.     

Flavonols and flavones of vegetables. V. Flavonols and flavones of root vegetables (author's transl)]

Root vegetables contain flavon(ol) glycosides in tracers up to small amounts, while the level of their leaves are in part considerable (to more than 1 g/kg, calculated as aglycon). Radish, rutabagas, scorzoneras, and beets contain less than 1 mg/kg kaempferol and/or quercetin; carrots less than 1 mg/kg apigenin and luteolin; celery roots ca. 75 mg apigenin/kg and 14 mg luteolin/kg; horseradish about 20 mg kaempferol/kg and small radish 1-10 mg kaempferol/kg, whereby all these flavones and flavonols occur as glycosides in the vegetables. In leaves of small radish, variety "Eiszapfen", we found besides isoquercitrin (quercetin-3-glucoside) a quercetin-3-0-diglycoside and a kaempferol-0-diglycoside, both with the sugars rhamnose and arabinose, by tlc.     

不同前处理发酵的桑椹紫酒中黄酮醇物质的比较研究

采用反相高效液相色谱检测不同前处理发酵的桑椹紫酒中黄酮醇的含量,并与葡萄酒中黄酮醇的含量进行对比。结果表明,不同前处理桑椹紫酒中各类黄酮醇的含量除山萘酚,其余均差异极显著。桑椹紫酒中可以检测出10种黄酮醇。其中,槲皮素、杨梅素与葡萄酒中的含量相当,其余8种黄酮醇：山萘酚、异鼠李素、高良姜素、芦丁、非瑟酮、桑色素、鼠李素、芹菜素含量均比葡萄酒中的含量要高,且均在0.54 mg/L以上。     

An HPLc technique for flavonoid analysis in honey

A new technique for the analysis of flavonoids in honey has been developed. This uses filtration of honey through Amberlite-XAD-2 and purification of the flavonoid fraction by Sephadex LH-20. The flavonoid fraction is then analysed by HPLC. This technique allowed the identification of 16 flavonoids in honey, namely quercetin, kaempferol, 8-methoxykaempferol, quercetin 3-methyl ether, isorhamnetin, kaempferol 3-methyl ether, quercetin 3,3-dimethyl ether, quercetin 3,7-dimethyl ether, galangin, luteolin, apigenin, genkwanin, chrysin, luteolin 7-methyl ether, pinocembrin and pinobanksin. The flavonoids present in ten samples of honey from La Alcarria have been HPLC analysed by this technique. The fact that the flavonoid patterns are very similar, suggests that samples from other areas should be examined in order to assess if this procedure could be useful as an adjunct in studies of the geographical origin of honey.     

Metabolic pathways of the colonic metabolism of flavonoids (flavonols,flavones and flavanones) and phenolic acids

Flavonoids are metabolized by the gut microflora giving rise to a wide range of phenolic acids that may exert systemic effects in the body. Nevertheless, the colonic metabolism pathways and the function of the metabolites formed are poorly studied. In the present study, the individual colonic metabolism of three subclasses of flavonoids (flavonols, flavones and flavanones) and phenolic acids was evaluated. For this, seven standards of flavonoids (quercetin, quercetin–rhamnoside, quercetin–rutinoside, myricetin, luteolin, naringenin and kaempferol–rutinoside) and two phenolic acids (protocatechuic acid and gallic acid) were submitted to an in vitro fermentation model using rat colonic microflora. Simultaneously, a nuts–cocoa cream enriched with these standards of flavonoids was incubated and the colonic metabolism of these compounds was evaluated. The results showed that the greatest number of colonic metabolites came from the fermentation of quercetin and quercetin–rhamnoside, and the maximum concentration of fermentation products was observed after 48 h of fermentation. On the other hand, a smaller number of fermentation products were observed after the colonic fermentation of kaempferol–rutinoside, naringenin, luteolin and myricetin. The phenolic acids were slightly metabolized by the colonic microflora.     

Flavonoid content and antioxidant activity of vegetables from Indonesia

Extracts from 11 vegetables of Indonesian origin were screened for flavonoid content, total phenolics, and antioxidant activity. The flavonols myricetin, quercetin, and kaempferol and flavones luteolin and apigenin were quantified by HPLC. Flavonoid content in mg/100 g fresh weight (fw) was apparently initially reported for Cosmos caudatus H.B.K. (52.19), Polyscias pinnata (52.19), Pluchea indica Less. (6.39), Nothopanax scutellarius (Burm.f.) Merr (5.43), Talinum triangulare (Jacq.) Willd. (3.93), Pilea melastomoides (Poir.) Bl. (2.27), and Etlingera elatior (Jack) R.M.Sm (1.18). The flavonoid content of the vegetables studied were mainly quercetin and kaempferol and ranged from 0.3 to 143 mg/100 g fw, with the highest level found in Sauropus androgynus (L) Merr. C. caudatus H.B.K. had the greatest total phenols among the vegetables analysed, with 1.52 mg GAE/100 g fw. P. indica Less. and C. caudatus H.B.K. had the highest antioxidant activity as measured by ferric cyanide reducing power, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) scavenging, and inhibition of linoleic acid oxidation. Therefore, S. androgynus (L) Merr, C. caudatus H.B.K., and P. pinnata were identified as potentially rich sources of dietary flavonoids and antioxidants.     

三种黄酮醇化合物对H2O2 和CCl4 诱导的人肝细胞体外损伤的保护作用比较

黄酮醇是一类广泛存在于植物界中的多酚物质,并具有许多生理作用,在食品中具有较大的应用潜力。通过一些生化实验方法,研究了3 种黄酮醇(山奈素、槲皮素、杨梅黄酮)对由H2O2 和CCl4 诱导的人肝细胞(HL-7702细胞系)体外氧化损伤的保护作用,并研究了3 种黄酮醇的化学结构与其细胞保护作用之间的关系。结果表明,3种黄酮醇(20、40、60μmol/L)与肝细胞预先作用30min,再进行诱导损伤,可以提高肝细胞的细胞活率和还原型谷胱甘肽(GSH)含量水平,降低乳酸脱氢酶(LDH)渗出率和丙二醛(MDA)生成量。3 种黄酮醇的细胞保护能力大小顺序为槲皮素>杨梅黄酮>山奈素。结果显示,黄酮醇的细胞保护能力大小与其分子结构中B 环上羟基数目的多少无关。     

The flavonol content of peas as influenced by variety and light,and a note on the flavonol content of broad beans

The flavonol contents of the leaves and pods of peas are influenced particularly by the amount of light irradiation received, while varietal differences appear to be of lesser importance. The seeds contain only traces of flavonols (< 1 part/10⁶). Broad beans on the other hand contain ca 30–70 parts/10⁶ of flavonols, determined as kaempferol, quercetin and myricetin after hydrolysis of the respective glycosides. The flavonols are localised mainly in the skin. No myricetin could be detected in the pods and leaves.     

Comparative analysis of flavonoids in white and red table grape cultivars during ripening by widely targeted metabolome and transcript levels

The flavonoid metabolites were compared between red ‘Summer Black’ (SB) and white ‘Shine Muscat’ (SM) table grapes during fruit development based on widely targeted metabolome. A total of 134 flavonoids were identified in two cultivars, including 37 flavones, 33 flavonols, and 11 anthocyanidins, and so on. From young to veraison, the composition and the content of most flavonoids were decreasing in both cultivars but increased at maturation in SB. In general, SB has higher flavonoid compositions and content than SM during the whole fruit development, especially the content of anthocyanin after veraison. While the SM had higher content of flavonols such as quercetin, kaempferol and their derivatives. The expression of anthocyanin-related genes such as UFGT, OMT, GST, MATE, MYBA1, and MYBA2 was remarkably higher in SB than those in SM, which may attribute to higher anthocyanin content, while the higher expression of F3H and FLS resulted higher level of flavonols in SM. These results improve our understanding of flavonoid profiles and molecular mechanism in table grape cultivars.     

Study of flavonoids in aqueous spinach extract using positive electrospray ionisation tandem quadrupole mass spectrometry

The presence of three flavonols (quercetin, kaempferol, myricetin) and two flavones (apigenin, luteolin) were investigated in the extract of fresh spinach leaves. Aqueous spinach extracts were prepared with a leaf/water ratio of 1:2 at 80 °C for 30 min stirring. Ferric ammonium sulphate method was used for measuring total polyphenols in the extracts and expressed as catechins and tannic acid equivalents. The flavonoids glycosides in the extract were hydrolysed to their aglycons with 1.2 M HCl in boiling 50% water methanol solution. The resulting aglycons were identified and quantified by a C18 reverse phase high-performance liquid chromatography (RP-HPLC). Furthermore, the results were confirmed by HPLC coupled to an electrospray ionisation tandem triple-quadrupole mass spectrometer ESI-MS performing low-energy collision induced dissociation (CID-MS/MS) in the collision cell (HPLC-ESI-MS/MS). Analyses were made in the multiple reaction monitory (MRM) mode. Results showed that total polyphenols contents in fresh spinach leaves were 270 mg kg⁻¹ and 390 mg kg⁻¹ as tannic acid and catechin equivalents, respectively, in which, major flavonoids aglycons were apigenin (170 mg kg⁻¹), quercetin (50 mg kg⁻¹) and kaempferol (30 mg kg⁻¹).     

Flavonoids as biochemical markers of the plant origin of bee pollen

The flavonoid compounds present in almond (Prunus amygdalus, Rosaceae), Jara (Cistus sp Cistaceae), Echium sp (Boraginaceae) and Chrysanthemum sp (Compositae) bee pollens have been studied by TLC, 2D PC and HPLC techniques. These bee pollens show characteristic flavonoid patterns which allow their use as biochemical markers of their plant origin. In addition, the flavonoid patterns of natural almond and ?Jara’? pollens have been shown to be identical to those of the corresponding bee pollens confirming their use as chemical markers. The flavonoid aglycones obtained by acid hydrolysis of pollen flavonoids are also useful for identification purposes. Almond bee pollen contains 8-methoxykaempferol, kaempferol and quercetin 3-glycosides, ?Jara’? bee pollen produces quercetin and isorhamnetin 3-glycosides and trace amounts of myricetin and kaempferol 3-glycosides, Echium bee pollen contains mostly kaempferol 3-glycosides and traces of quercetin 3-glycosides, and Chrysanthemum contains kaempferol, apigenin, and quercetin 3-glycosides. The major compound in almond pollen, namely 8-methoxykaempferol 3-glycoside, was not detected in the related apple, pear, cherry and plum pollens.