Sugars,acids, ethyl β-d-glucopyranose and a methyl inositol in sea buckthorn (Hippophaë rhamnoides) berries

Sea buckthorn berry is a rich source of nutrients and bioactive components beneficial for human health. Sugars and acids play an important role in determining the sensory properties of the berry. Sugars, acids, ethyl β-d-glucopyranose and a methyl inositol were analysed in berries of three subspecies (Hippophaë rhamnoides ssp. sinensis, rhamnoides and mongolica) collected from China, Finland and Russia over four consecutive years. Fructose and glucose were the major sugars, and the dominating acids were malic and quinic acids. Origin and harvesting date have significant impacts on sugars, acids and sugar/acid ratio in the berry. During the harvesting period, the sugar content followed different changing patterns in berries of different subspecies. Ethyl glucose dominated in the sugar fraction of ssp. rhamnoides but existed only in trace amounts in the other two subspecies. In ssp. rhamnoides, the level of ethyl glucose increased during the harvesting period; the increase was accompanied by a decrease in glucose content, indicating the presence of a biochemical pathway converting glucose into its derivatives. A methyl inositol was identified for the first time in sea buckthorn with higher levels found in ssp. sinensis than in the other two subspecies. The levels of ethyl glucose and methyl inositol may be important sensory and nutritional quality factors of sea buckthorn berry. The data presented by this study provide important chemotaxonomic information characterising different subspecies of sea buckthorn and useful guidance for breeding, harvesting, and industrial utilisation of sea buckthorn.     

Influence of origin,harvesting time and weather conditions on content of inositols and methylinositols in sea buckthorn (Hippophaë rhamnoides) berries

Inositols and methylinositols play an important role in human physiology. Inositols and methylinositols in berries of three subspecies of sea buckthorn (Hippophaë rhamnoides) were analysed using gas chromatography combined with a flame ionisation detector and mass spectrometry. The wild Chinese berries (H. rhamnoides ssp. sinensis) contained higher levels of l-quebrachitol (1l-2-O-methyl-chiro-inositol) and methyl-myo-inositol (average 615 and 58 mg/100 ml juice, respectively) than the Finnish (H. rhamnoides ssp. rhamnoides, 276 and 11 mg/100 ml juice, respectively) and the Russian (H. rhamnoides ssp. mongolica, 228 and 16 mg/100 ml juice, respectively) berries (P < 0.001). The content of myo-inositol was higher in the Chinese and the Russian berries than in the Finnish berries (26 and 20 mg/100 ml juice vs. 8 mg/100 ml juice, P < 0.001). In the Chinese berries, the contents of methyl-myo-inositol and l-quebrachitol increased, whereas that of myo-inositol decreased from late September to late November. The content of the l-quebrachitol in the Chinese berries correlated negatively with the air temperature and the number of frost-free days, suggesting a possible role of the compound in the cold resistance of sea buckthorn.     

Identifizierung von Kiwi in Fruchtprodukten mittels HPLC

Zusammenfassung Eine Methode zur Identifizierung von Kiwi in Fruchtprodukten wird beschrieben. Das Flavonoidmuster von Kiwifrüchten aus unterschiedlichen Anbauländern wurde erstmals qualitativ und quantitativ mittels HPLC untersucht. Das charakteristische Flavonoidmuster setzt sich aus Quercetin-3-O-rutinosid, Quercetin-3-O-glucosid, Kämpferol-3-O-rutinosid, Kämpferol-3-O-galaktosid, Quercetin-3-O-rhamnosid und Kämpferol-3-O-rhamnosid zusammen. Ebenfalls erstmalig wurde die zur Fruchtsaftherstellung verwendete Mombinpflaume auf flavonoide Inhaltsstoffe untersucht. Identifiziert wurde lediglich das Hauptflavonoid Quercetin-3-O-rutinosid (Rutin). Die Flavonoide wurden durch Säulenchromatographie an Polyamid isoliert und mittels RP-HPLC (H₂O/Acetonitril-Gradient) getrennt. Die Identifizierung erfolgte über die Aufnahme von UV-Spektren mit Dioden-Array-Detektor und durch Co-Chromatographie. Die Struktur des Kämpferol-3-O-rhamnosids wurde nach präparativer Isolierung mit chemischen, chromatographischen und spektroskopischen Methoden ermittelt.

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Identification of kiwi in fruit products by HPLC

Summary A method has been developed for the identification of kiwi in fruit products. In different samples of kiwi the flavonoids were examined by high-performance liquid chromatography (HPLC) with respect to their quality and quantity. In this investigation, kiwi containing quercetin-3-O-rutinoside, quercetin-3-O-glucoside, kaempferol-3-O-rutinoside, kaempferol-3-O-galactoside, quercetin-3-O-rhamnoside, and kaempferol-3-O-rhamnoside as flavonoid compounds were analysed. The mombin plum has also been analysed for phenolic compounds for the first time. The mombin is used for producing fruit juice. The major compound of the flavonoids in the above-mentioned fruits is quercetin-3-O-rutinoside. Flavonol glykosides were isolated by column chromatography with polyamide. A RP-HPLC method with gradient elution (solvent A: H₂O; solvent B: acetonitrile) was used for the separation of the flavonol glycosides. Identification was carried out by UV spectra using a diode-array detector. Kaempferol-3-O-rhamnoside was isolated using preparative HPLC. The structure was established by chemical, chromatographical and spectroscopical methods.

     

Biological activities of flavonoids from Nitraria retusa (Forssk.) Asch. and their acylated derivatives

The antioxidant activity and antiproliferative property towards Caco2 cells of water and methanol extracts/fractions of Nitraria retusa were investigated. The total phenolic and flavonoid contents of the extracts/fractions were determined, and the four major flavonoids were identified as isorhamnetin, isorhamnetin-3-O-glucoside, isorhamnetin-3-O-rutinoside and isorhamnetin-3-O-robinobioside. The results showed a relationship between the extracts/fractions activities and their flavonoid contents. Moreover, the chloroform extract which was enriched with the aglycone flavonoid isorhamnetin exhibited the highest activities. The activities of N. retusa flavonoids were compared to those of model flavonoids, quercetin, isoquercitrin and rutin. In all cases, the aglycone compounds were more active than their glycosylated derivatives. Isorhamnetin-based flavonoids presented higher antiproliferative activities than quercetin-based ones, while similar antioxidant properties were observed. The enzymatic acylation of isorhamnetin-3-O-glucoside with ethyl laurate and ethyl butyrate enhanced its capacity to inhibit xanthine oxidase and its antiproliferative activity but decreased its radical scavenging activity.     

Identification,quantification and antioxidant activity of acylated flavonol glycosides from sea buckthorn (Hippophae rhamnoides ssp. sinensis)

A novel acylated flavonol glycoside: isorhamnetin (3-O-[(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1 → 2)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside) (1), together with two known acylated flavonol glycosides: quercetin (3-O-[(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1 → 2)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside) (2) and kaempferol (3-O-[(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1 → 2)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside) (3) were isolated from the n-butanol fraction of sea buckthorn (Hippophae rhamnoides ssp. sinensis) berries for the first time by chromatographic methods, and their structures were elucidated using UV, MS, ¹H and ¹³C NMR, and 2D NMR. Compounds 1–3 showed good scavenging activities, with respective IC₅₀ values of 8.91, 4.26 and 30.90 μM toward the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical; respective Trolox equivalent antioxidant capacities of 2.89, 4.04 and 2.44 μM μM⁻¹ toward 2,2′-azino-bis-3-ethyl-benzothiazoline-6-sulphonate (ABTS) radical. The quantitative analysis of the isolated acylated flavonol glycosides was performed by HPLC–DAD method. The contents of compounds 1–3 were in the range of 12.2–31.4, 4.0–25.3, 7.5–59.7 mg/100 g dried berries and 9.1–34.5, 75.1–182.1, 29.2–113.4 mg/100 g dried leaves, respectively.     

Headspace volatiles from frozen berries of sea buckthorn (Hippophaë rhamnoides L.) varieties

The volatile compounds of frozen berries of seven sea buckthorn (Hippophaë rhamnoides L.) varieties of two growing seasons were isolated with solid phase microextraction (SPME), and analyzed with gas chromatography mass spectrometry. A total of 45 volatiles were identified from the headspace. The most numerous compounds found were esters of short chain normal or branched alcohols and acids. Ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl hexanoate, 3-methylbutyl 3-methylbutanoate, ethyl octanoate and 3-methylbutyl hexanoate were the most abundant compounds identified, and they contribute over 70% of the total peak area found in samples. Principal component analysis (PCA) showed differences between the years studied as well as between varieties. Raisa of ssp. rhamnoides origin had the highest variance in the volatile profile compared to the varieties of ssp. mongolica origin.     

Chemical characterization and antioxidant capacity of berries from Clidemia rubra (Aubl.) Mart. (Melastomataceae)

The flora of Latin America attracts gaining interest as it provides a plethora of still unexplored or under-utilized fruits that can contribute to human well-being due to their nutritional value and their content of bioactive compounds. Clidemia rubra (Aubl.) Mart. is a shrub belonging to the family of the Melastomataceae that grows preferably in a tropical climate. This paper comprises a nutritional characterization of the berries from Clidemia rubra and provides data on the phenolic compounds as well as the antioxidant capacity of the fruit. Findings in macronutrients like protein, carbohydrates, and fat were comparable to that of common berry fruits. Clidemia rubra berries seemed to be a good source for dietary fibers and some minerals (Ca, Mn, and Zn). In contrast, contents of titratable acids and ascorbic acid were low. The polyphenolic profile was determined by using HPLC-MS/MS in comparison to standard compounds. Noteworthy amounts of cyanidin 3-O-rutinoside (39.43 ± 1.66 mg/100 g fresh weight (FW)), delphinidin 3-O-rutinoside (23.74 ± 1.18 mg/100 g FW), cyanidin 3-O-glucoside (11.68 ± 0.56 mg/100 g FW), and delphinidin 3-O-glucoside (6.08 ± 0.35 mg/100 g FW) were found. Non-anthocyanin phenolic constituents were phenolic acids (gallic, protocatechuic, p-hydroxy-benzoic, vanillic, and caffeic acid), flavan-3-ols (epigallocatechin, epigallocatechin gallate, and epicatechin gallate), and 11 different myricetin and quercetin derivatives of which quercetin 3-O-arabinoside (5.26 ± 0.16 mg/100 g FW) and quercetin 3-O-rhamnoside (5.06 ± 0.08 mg/100 g FW) were dominating. Anthocyanins and ascorbic acid were mainly responsible for the antioxidant capacity of Clidemia rubra berries assessed with the total oxidant scavenging capacity (TOSC) assay.     

Sugars, sugar alcohols, fruit acids, and ascorbic acid in wild Chinese sea buckthorn (Hippophaë rhamnoides ssp. sinensis) with special reference to influence of latitude and altitude

Wild berries of Hippophaë rhamnoides ssp. sinensis were collected from nine natural growth sites in China in three consecutive years in order to get an overall profile of the sugars, sugar alcohols, fruit acids, and ascorbic acid, and especially of the influence of the latitude and altitude of the growth place on these components. The contents of fructose, glucose, and l-quebrachitol in the berry juice varied in the ranges of 0.01-7.17, 0.05-7.85 and 0.21-1.09 g/100 mL, respectively, those of malic, quinic, and ascorbic acids were 1.55-8.84, 0.07-2.94, and 0.25-1.66 g/100 mL, respectively. The berries from Hebei and Inner Mongolia were characterized by high contents of sugars and l-quebrachitol and low contents of malic acid and ascorbic acid. In contrast, the berries from Sichuan and Qinghai contained lower contents of sugars and higher contents of malic acid and ascorbic acid than the berries from other growth areas. The berries from Sichuan differed considerably from others by the remarkably low contents of sugars and the exceptionally high contents of acids. The contents of fructose, glucose, and total sugar decreased as the altitude increased and as the latitude decreased (p < 0.05). In contrast, the contents of malic acid and ascorbic acid increased as the altitude increased and as the latitude decreased (p < 0.05). The contents of quinic acid and l-quebrachitol correlated strongly and positively with the latitude (p < 0.01).     

不同产地无糖绿茶饮料滋味特征差异分析

对市售不同产地无糖绿茶饮料滋味品质及其化学成分进行分析比较,以期明确无糖绿茶饮料中的主要滋味物质,探究不同产地绿茶饮料间滋味特征的差异性。结果表明,不同产地绿茶饮料的滋味因子和色差差异不明显,其中日本绿茶饮料的整体滋味品质较优。日本和中国台湾绿茶饮料中茶多酚、咖啡碱、黄酮、可溶性糖质量浓度和儿茶素总量、黄酮苷总量、阳离子总量都明显高于中国大陆绿茶饮料。有13 种化学组分与感官评分相关性较高,其中茶多酚（0.910）、黄酮（0.917）、Mn2＋（0.912）质量浓度与绿茶饮料滋味浓度呈极显著正相关（P＜0.01）;咖啡碱（0.830）质量浓度与绿茶饮料滋味苦度呈极显著正相关（P＜0.01）;牡荆素-2’’-O-鼠李糖苷（Vit-rha）（0.862）、Al3＋（0.811）质量浓度与绿茶饮料滋味涩度呈极显著正相关（P＜0.01）。滋味贡献度（dove-over-threshold,Dot）分析发现黄酮及其苷元对无糖绿茶饮料涩味起主要贡献,包括槲皮素-3-O-芸香糖苷（Que-rut）、山柰酚-3-O-芸香糖苷、槲皮素-3-O-半乳糖苷、槲皮素-3-O-葡萄糖苷、杨梅素-3-O-半乳糖苷、Vit-rha,其中Que-rut的Dot值最高;咖啡碱对无糖绿茶饮料苦味起主要贡献。     

Selection of elderberry (Sambucus nigra L.) genotypes best suited for the preparation of elderflower extracts rich in flavonoids and phenolic acids

The importance of raw material and extraction parameters for obtaining a high content of flavonoids and phenolic acids in elderflower extracts was investigated. Nine phenolic acids (3-O-, 4-O-, and 5-O-caffeoylquinic acid, 3-O- and 5-O-p-coumaroylquinic acid, 1,5-di-O-, 3,4-di-O-, 3,5-di-O- and 4,5-di-O-caffeoylquinic acid) and six flavonol glycosides (quercetin-3-O-rutinoside, quercetin-3-O-glucoside, kaempferol-3-O-rutinoside, isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucoside, and quercetin-3-O-6″-acetylglucoside) were identified and quantified in elderflowers and/or extracts thereof by liquid chromatography-mass spectrometry (LC-MS) and high-performance liquid chromatography-diode array detection (HPLC-DAD), respectively. The yield of elderflower extracts depended significantly on processing conditions and raw material properties and the maximum yield of elderflower extract was obtained by extraction for a maximum of 10 days at 4 °C using an extraction liquid consisting of a maximum of 20 w/w % sugars and 5% citric acid. The effects of the extraction liquid composition and raw material on the concentration of phenolic acids and flavonol glycosides in elderflower extracts were determined by factor analysis. Several elderberry genotypes were found to be useful for processing of elderflower extracts with a relative high concentration of phenolic acids and flavonol glycosides.     

Comparison of phenolic composition and antioxidant properties of two native Chilean and one domestic strawberry genotypes

The phenolic composition of extracts from the forms chiloensis and patagonica of Fragaria chiloensis were compared with that of the commercial strawberry Fragaria × ananassa cv. Chandler by high performance liquid chromatography with diode-array detector (HPLC–DAD) and high performance liquid chromatography with electrospray ionization mass spectroscopy detector (HPLC–ESI–MS). The phenolic constituents in the three species were mainly proanthocyanidins, hydrolysable tannins, anthocyanins and flavonol glycosides. In both native strawberry species the main flavonol glycoside was quercetin 3-O-glucuronide and the minor anthocyanins identified were cyanidin-malonyl-glucoside and pelargonidin-malonyl-glucoside. The highest anthocyanin content was found in the commercial red strawberry while ellagic acid was the main phenolic in the native white strawberry. From the methanolic fruit extract of the native Chilean strawberry Fragaria chiloensis ssp. chiloensis f. chiloensis four known antioxidants were isolated by selective fractionation using the bleaching of the free radical scavenger 1,1-diphenyl-2-picrylhydrazyl (DPPH) as the guiding assay. The antioxidant properties (measured as the bleaching of the DPPH radical) were determined for methanol extracts of the three fruits, for fractions of F. chiloensis ssp. chiloensis f. chiloensis, and for the isolated compounds cyanidin-3-glucoside, pelargonidin-3-glucoside, quercetin-3-glucuronide and ellagic acid. This study allows a clear chemical differentiation between the commercial strawberry and the Chilean white strawberry.     

Identification and quantification of flavonol aglycons in cactus pear (Opuntia ficus indica) fruit using a commercial pectinase and cellulase preparation

The applicability of pectinases and cellulases as soft hydrolysing agents on flavonol glycosides was investigated for identification and quantification of flavonol aglycons in cactus pear fruit. Freeze-dried samples of cactus pear fruit’s peel (cactus pear peels) and onions were treated with commercial pectinase and cellulase preparations at 50 °C for different time periods (up to 16 h). Additionally isorhamnetin-3-O-rutinoside and quercetin-3,4′-O-diglucoside were used as model compounds. In parallel, samples of cactus pear peels and onions were treated by the traditional acidic hydrolysis using HCl. Following hydrolysis, flavonols were characterised using HPLC–DAD. Enzymatically, all model compounds and plant material were highly hydrolysable. Flavonol glycosides were completely hydrolysed after 16 h (cactus pear) and 4 h (onion), respectively. While the acidic hydrolysis caused degradation of the flavonols and produced protocatechuic acid as a degradation product, the enzymatic hydrolysis gave gentle effects and did not produce any protocatechuic acid at all.     

LC-MS–MS characterisation of curry leaf flavonols and antioxidant activity

Curry leaf (Murraya koenegii) is a common flavouring agent in Indian foods. This study characterised the flavonol profile of curry leaf extracted with different solvents and the relative antioxidant capacity of these extracts by quantifying phenolic constituents. Flavonols were extracted using ethanol, methanol, or acetone prior to identification and quantification using liquid chromatography coupled to atmospheric pressure chemical ionisation (APCI) mass spectrometry in tandem mode (LC-MS–MS) with negative ion detection. Major curry leaf flavonols included myricetin-3-galactoside, quercetin-O-pentohexoside, quercetin-3-diglucoside, quercetin-3-O-rutinoside, quercetin-3-glucoside, quercetin-3-acetylhexoside, quercetin-O-xylo-pentoside, kaempferol-O-glucoside, and kaempferol-aglucoside. Lag-time and TBARS tests demonstrated that curry leaf phenolics prevent cupric-ion induced oxidation of LDL. The best extraction yield was obtained with 80% ethanol. Acetone extracts provided better antioxidant activity expressed as increased lag-time formation, than did ethanol or methanol extracts. Curry leaf is a rich source of flavonols that have biological activity in vitro and further studies are warranted in regards to the potential health benefits and identification of the novel flavonols whose identities remain unknown.     

Analysis of flavour compounds and prediction of sensory properties in sea buckthorn (Hippophaë rhamnoides L.) berries

The aim of this study was to investigate sugars, organic acids, flavonol glycosides (FGs), proanthocyanidins and volatiles as flavour compounds in sea buckthorn (SB) berries of five cultivars and to predict the sensory properties of berries. The profiles of flavour compounds in SB berries varied significantly among the cultivars. Total proanthocyanidins and FGs were highest in ‘Pertsik’ and ‘Raisa’, respectively. Total volatiles were highest in ‘Vorobyevskaya’ and lowest in ‘Raisa’. A previously established PLS model was used to predict the sensory properties of SB berries based on the non-volatile flavour compounds. The mouth-drying astringency can be predicted the most reliably, which has the highest regression coefficients with quinic acid, isorhamnetin-3-O-sophoroside-7-O-rhamnoside and total proanthocyanidins. Bitterness cannot be predicted using the model. ‘Pertsik’ berries were predicted to be more mouth-drying astringency and sour than those of ‘Raisa’. The research supports the cultivar selection in cultivation and industry of SB berries.     

不同整形方式对‘赤霞珠’葡萄果皮非花色苷酚的影响

以欧亚种酿酒葡萄‘赤霞珠’为试材,通过高效液气相色谱-质谱联用法研究单干单臂、单干双臂和单干双层双臂3 种整形方式对葡萄果皮非花色苷酚类物质的影响,并采用聚类分析和偏最小二乘判别分析（partial least squares-discrimination analysis,PLS-DA）筛选不同整形方式间单体非花色苷酚的差异组分。结果表明：与单干单臂和单干双层双臂整形相比,单干双臂整形可以提高葡萄果皮中的槲皮素-3-O-葡萄糖醛酸苷、槲皮素-3-O-葡萄糖苷、山柰酚-3-O-半乳糖苷、槲皮素-3-O-鼠李糖苷类黄酮醇物质的含量;单干单臂和单干双臂整形葡萄果皮中杨梅酮-3-O-葡萄糖苷、异鼠李亭-3-O-葡萄糖苷、丁香亭-3-O-葡萄糖苷类黄酮醇类物质和表没食子酸儿茶素、儿茶素类黄烷醇类物质及原儿茶酸类、香草酸酚酸类物质的含量均高于或显著高于单干双层双臂整形,而单干双层双臂整形葡萄果皮中仅原花色素C1的含量较高。聚类分析结果显示,部分单体非花色苷酚类物质受年份的影响较大,且单干单臂和单干双臂整形对非花色苷酚类物质的影响模式类似,而两者与单干双层双臂整形区别较大。PLS-DA结果表明,不同整形方式的葡萄果皮中单体非花色苷酚类物质组分差异较大。槲皮素-3-O-葡萄糖苷、杨梅酮-3-O-葡萄糖苷等黄酮醇类物质是3 类整形方式所处理的葡萄果皮的主要差异组分,且对单干双臂整形处理组的贡献值较大,单干双臂整形的葡萄果皮中含有较高的黄酮醇类物质含量。综上,单干双臂整形方式有助于葡萄果皮非花色苷酚类物质的积累,可被应用于陕西关中地区酿酒葡萄的栽培生产中。     

Characterisation of volatiles and polyphenols for quality assessment of alcoholic beverages prepared from Corsican Myrtus communis berries

In the present work, the essential oil compositions of Myrtus communis berries from ten Corsican localities were studied and no chemical variability was observed. HS–SPME, GC and GC/MS analysis were carried out for the characterisation of volatile fractions of M. communis berries and two derived commercial alcoholic beverages (liqueur and eau-de-vie). Quantitative variations due to the distillation process were observed between the two beverages. The volatile compositions of Corsican myrtle alcoholic products were characterised by high amounts of monoterpene hydrocarbons and oxygenated monoterpenes with α-pinene and 1,8-cineole as major components. The polyphenolic compositions of the berry extract and the liqueur were also established using HPLC–DAD and LC–MS–MS; high concentrations of flavonol glycosides, flavonols and flavanols were reported.     

Flavonols, betacyanins content and antioxidant activity of cactus Opuntia macrorhiza fruits

Flavonols, betacyanins content and antioxidant activity of red-purple cactus Opuntia macrorhiza fruits, a promising cactus pear species, were evaluated in comparison to the well known cactus pear fruits of Opuntia ficus-indica. Flavonol profile was evaluated by HPLC-DAD prior to and after enzymatic hydrolysis (glycosides vs. aglycons). In addition betacyanins, responsible for the purple to red color of cactus pear fruits were also estimated and compared to Beta vulgaris ssp. (roots) and red O. ficus-indica fruits. In all cases, cactus fruit pulps showed no flavonols at all. While different derivatives of isorhamnetin glycosides were found in O. ficus-indica fruit's peel, isorhamnetin-3-O-rutinoside was the only compound in O. macrorhiza fruit. Correspondingly, antioxidant activity assays showed a high antioxidant activity of both, O. macrorhiza fruit's peel and pulp. With regard to betacyanins, O. macrorhiza fruit's peel and pulp provide a deep red-purple color, whose average impact is higher compared to red beet (B. vulgaris spp.) and about 8-fold higher than red fruits from O. ficus-indica. Supporting these results, estimation of color attributes (L*, a*, b*, C and H°) showed also a high color impact of both O. macrorhiza fruit's peel and pulp.     

Bestimmung von Rutin (Quercetin-3-O-rutinosid) in schwarzem Tee mittels HPLC

Zusammenfassung Die Flavonolglykoside wurden durch Säulenchromatographie an Polyamid isoliert und mittels RP-HPLC (Essigsäure: Acetonitril-Gradient) getrennt. Die Identifizierung erfolgte durch UV-Spektren mittels Dioden-Array-Detektor und durch Co-Chromatographie. Das wegen seiner physiologischen Wirkung besonders interessante Rutin wurde quantitativ bestimmt. Die Werte lagen zwischen 86 and 214 mg/100 g, wenn mit heißem Wasser extrahiert wurde.

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Determination of quercetin-3-O-rutinoside in black tea by HPLC

Summary Flavonol glycosides were isolated from black tea by column chromatography with polyamide. A RP-HPLC method with gradient elution (solvent A: 2% acetic acid; solvent B: acetonitrile) was used for the separation of the flavonol glycosides. Identification was carried out by UV spectra using a diode-array detector. Among these compounds rutoside is of special interest because of its physiological activity. The amounts in black tea were 86 to 214 mg/100 g, if extracted with hot water only.

     

Phytochemical profiles and inhibitory effect on free radical-induced human erythrocyte damage of Dracaena draco leaf: A potential novel antioxidant agent

The present study reports for the first time the metabolite profile and antioxidant activity of aqueous extract obtained from Dracaena draco L. leaf. Volatiles profile was determined by HS-SPME/GC-IT-MS, with 34 compounds being identified, distributed by distinct chemical classes: 2 alcohols, 5 aldehydes, 16 carotenoid derivatives and 8 terpenic compounds. Carotenoid derivative compounds constituted the most abundant class in leaf (representing 45% of total identified compounds). Phenolics profile was determined by HPLC/DAD and 9 constituents were identified: 2 hydroxycinnamic acid derivatives – 5-O-caffeoylquinic and 3,5-O-dicaffeoylquinic acids; 4 hydroxycinnamic acids – caffeic, p-coumaric, ferulic and sinapic acids and 3 flavonol glycosides – quercetin-3-O-rutinoside, kaempferol-3-O-glucoside and kaempferol-3-O-rutinoside. The most abundant phenolic compound is quercetin-3-O-rutinoside (representing 50.2% of total polyphenols). Organic acids composition was also characterised, by HPLC–UV and oxalic, citric, malic and fumaric acids were determined. Oxalic and citric acids were present in higher amounts (representing 47%, each). The antioxidant potential of this material was assessed by the ability to protect against free radical-induced biomembrane damage, using human erythrocyte as in vitro model. Leaf extract strongly protected the erythrocyte membrane from haemolysis (IC₅₀ of 39 ± 11 μg/ml), in a time- and concentration-dependent manner. This is the first report showing that D. draco leaf is a promising antioxidant agent.