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A simple, rapid, and precise high-performance thin-layer chromatographic method has been established for quantitative analysis of myricetin in the stem bark of Myrica esculenta, family Myricaceae. The marker myricetin was separated from other components of stem bark extract on silica gel 60 F254 HPTLC plates with toluene-ethyl acetate-formic acid-methanol 3:3:0.6:0.4 (v/v) as mobile phase. Densitometry in absorbance-reflection mode at 268 nm was used for quantitative analysis of myricetin. The stem bark of M. esculenta was found to contain 0.225% (w/w) myricetin. The method was validated for linearity, accuracy, precision, and specificity in accordance with ICH guidelines. The calibration plot was linear between 0.4 and 2.0 μg per band for myricetin. The limits of detection and quantitation were 0.0939 and 0.2845 μg per band, respectively. The method can be used as a quality control-method for fingerprint profiling and quantitative analysis of the stem bark of Myrica esculenta.
Asensitive, selective, and precise high-performance thin-layer chromatography (HPTLC) method was developed for simultaneous analysis of six bioactive phenolic compounds, i.e., juglone, quercetin, myricetin, rutin, caffeic acid, and gallic acid in methanol extract and its fractions (hexane, chloroform, ethyl acetate, and butanol fractions) from bark of Juglans regia. Good separation was achieved on RP-18 F254S TLC plate using methanol-water-formic acid-acetic acid (48.8:46.4:2.4:2.4, ν/ν). The densitometric determination of the compounds was carried out at 254 nm in reflectance/absorbance mode. The method was validated in terms of linearity, sensitivity, accuracy, precision, robustness, and specificity. The linear regression data for the calibration plots of the reference compounds showed a good linear relationship with higher correlation coefficient (r
2 ≥ 0.997). Accuracy of the method was evaluated in terms of average percent recovery, which ranged from 98.63 to 101.06%. HPTLC results revealed qualitative and quantitative differences in the phenolic compounds in the extract and fractions. The ethyl acetate fraction contained gallic acid followed by myricetin, rutin, quercetin, and caffeic acid in higher amount in comparison to the extract and fractions. The present method can be used for routine quality control of J. regia extracts.
Thin-layer chromatography with densitometric detection has been used for qualitative and quantitative analysis of the myricitrin content of extracts of the leaves of 20 species of the Aceraceae family. The presence of myricitrin was confirmed in five of the samples. The mobile phase was optimized for quantitative analysis of myricitrin without extract purification. Myricitrin standard was obtained from one of the extracts; its identity was confirmed chromatographically and by use of spectral methods. Implications for chemotaxonomic and phytochemical research are discussed.
Summary
A reversed-phase high-performance liquid chromatographic method was developed for the first time to simultaneously determine salicin and eight flavonoids in leaves of Salix matsudana, that is salicin, luteolin-7-O-glucoside, myricetin, apigenin-3′-oxyethyl-7-O-glucoside, rutin, quercetin, luteolin, kaempferol and apigenin. The separation of these compounds was achieved on a reversed phase C18 column (250 × 4.6 mm, 5 μm), with linear gradient of methanol in 0.2% phosphoric acid solution with a flow rate of 1.0 mL/min with UV detection at 246 nm. The calibration curves for the determination of all analytes showed good linearity over the investigated ranges (r > 0.999). The % relative standard deviation (% RSD) values were less than 0.34%, and the recoveries were between 95.79% and 99.94%. The values of luteolin-7-O-glucoside, salicin, myricetin, apigenin-3′-oxyethyl-7-O-glucoside, rutin, quercetin, luteolin, kaempferol, and apigenin were 1.0 μg g−1, 20.0 μg g−1, 32.9 μg g−1, 2.0 μg g−1, 29.5 μg g−1, 6.0 μg g−1, 1.0 μg g−1, 3.5 μg g−1, and apigenin was not found in the sample. This developed method can be used for evaluating the quality of different plant materials.
The content of the potentially health-defensive and disease-preventive flavonoids quercetin, kaempferol, myricetin, apigenin and luteolin of 31 vegetables were determined by RP- HPLC with UV detection. Vegetables were purchased at the local markets in Budapest at a period of their most frequent consumption. Quercetin levels in the edible parts of most vegetables were generally below 10 mg kg &1, except for onions (67&121.5 mg kg &1), lettuce (13.5&35.0 mg kg &1), dill (74.5 mg kg &1), broccoli (15.5 mg kg &1) and spinach (272.2 mg kg &1). Kaempferol was below 30 mg kg &1 except for parsnip (66.4 mg kg &1) and leek (45.8 mg kg &1). Myricetin could only be detected in lettuce, Swedish turnip, parsley and celery leaves, and dill. Detectable amount of luteolin was in radishes, some representatives of Brassica, sweet peppers, celery leaves and spinach while apigenin was only in Swedish turnip, celery root and celery leaves. These data provide a basis for the evaluation of the average daily intake of Hungarian population and for an epidemiological evaluation of health-promoting effects of flavonoids.
The content of potentially antioxidant, anticarcinogenic and antiallergic flavonoid aglycons, quercetin, kaempferol, myricetin, apigenin and luteolin of 45 fruits were determined by RP-HPLC with UV detection. Fresh and dried fruits were purchased in the local markets in Budapest at a period of their most frequent consumption. Total flavonoid content of fruits varied between 0–1000 mg kg –1, the average concentration was about 30 mg kg –1 fresh weight. Quercetin could be detected in most fruits, namely in apples, pear, plums, sweet and sour cherry and berries between 10–53 mg kg –1. Luteolin at a concentration of 20 mg kg –1 was found in melons, apples, kiwi and lemon. Myricetin was in detectable amount in redcurrant, and at very high concentration in some berry fruits (mulberry 453 mg kg –1, raspberry 540 mg kg –1, blackberry 636 mg kg –1, strawberry 994 mg kg –1), and in walnut (4565 mg kg –1). Kaempferol and apigenin were not found in the fruits investigated. None of the five flavonoids was found in some variety of grapes, in peach, pear, banana, orange, grapefruit and tangerine, in nuts such as almond, pistachio, nuts, and in dried fruits such as raisin, date, fig and prunes. These data provide a basis for the evaluation of the average daily intake of Hungarian population and for an epidemiological evaluation of health-promoting effects of flavonoids. __
Nine phenolic compounds (gallic acid, (+)catechin, vanillic and caffeic acid, p-coumaric acid, resveratrol, myricetin, quercitrin and quercetin) of fourteen Eger (Hungarian) young red wines were investigated using high-performance liquid chromatography in order to obtain data on the 2003 vintage. The grapes were harvested at different sites of the wine-district, vinified with same technology, but stored under different conditions (glass holder or 5-10 years old oak barrel). Same varietal wines originating from different sites of Eger wine-region showed considerable alterations in some phenolic components, and we found distinction in polyphenol content of different varietal wines originating from the same harvesting site. Cluster analysis was performed to acquire information about the similarity among the measured wines. Our study provides new data of polyphenol composition for Eger (Hungary) pure varietal red wines, and the results contribute to better identification of Hungarian red wines on the basis of geographical location.
The present work is the first phytochemical investigation of Euphorbia davidii Subils. After multistep separation process, three flavonoid glycosides were obtained from the ethyl acetate soluble fraction of the methanol extract of the whole plant. The structures of the isolated compounds were determined as kaempferol 3-O-rhamnoside, myricetin 3-O-rhamnoside, and quercetin 3-O-rhamnoside. Aqueous and organic extracts of the plant were screened in vitro for antiproliferative activity against HeLa (cervix epithelial adenocarcinoma), A431 (skin epidermoid carcinoma), A2780 (ovarian carcinoma) and MCF7 (breast epithelial adenocarcinoma) cells, using the MTT assay. n-Hexane and chloroform extracts demonstrated moderately dose-dependent cell growth inhibitory activity against all four cell lines.
Phenolic extract from banana peel was extracted with 95% ethanol and characterized by LC-TOF-MS/MS. Epicatechin, rutin, 3,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzoic acid, myricetin, ferulic acid, chlorogenic acid, and gallic acid were detected in the extract. Cholate test was performed for the initial examination of the hypolipidemic effect of the dietary fibres. The dietary fibres prepared by sequential treatment with sulphuric acid then sodium hydroxide (SST) and sodium hydroxide treatment (SHT) had high water-holding capacities (7.48 and 6.91 g g−1) and swelling capacities (4.8 and 4.3 ml g−1). The dietary fibres prepared by sequential treatment with trypsin then sulphuric acid (TST) and sulphuric acid treatment (SAT) had high oil-holding capacities (5.52 and 5.10 g g−1) and enhanced capacities for sodium cholate adsorption. Results indicated the potentials of banana peel as functional ingredient in food applications.
For prevention of non-infectious diseases such as cancer, and cardiovascular disorders consumption of more and more fruits and vegetables is highly advised. Fruits of Ribes and Rubus species are very popular in Hungary. Antioxidant properties of these fruits are well known, but the values of the characteristics depend on several factors including species, cultivars, soil and climate conditions, water and nutrition supply, and so on. Phenolics in several cultivars of raspberry, blackberry and currants grown in Hungary were measured. Total polyphenols and anthocyanins were detected by spectrophotometric methods while flavonoids including apigenin, luteolin, kaempferol, myricetin, quercetin and also ellagic acid were quantified by RP-HPLC technique. Total polyphenol contents of raspberry (yellow and red cultivars), blackberry and currants (white, red and black cultivars) were 219, 244, 379, 333, 192 and 533 mg/100 g, respectively. The concentrations of anthocyanins in the same order were 1.0, 41.9, 145, 0.2, 46 and 354 mg/100 g. Apigenin, luteolin and kaempferol could not been detected in any of the samples. Ellagic acid (2.0 to 23.7 mg/100 g) could be measured in white and red raspberries, in blackberries, and in some red and white currant cultivars. Quercetin could be detected in all berry species ranging from 0.1 to 14.4 mg/100 g. Measurable amount of myricetin was observed only in black currant cultivars between 1.5 and 7.7 mg/100 g. Polyphenols including flavonoids and anthocyanins in berry fruits are important forms of natural antioxidants. These molecules play essential role in the prevention of diseases in the pathomechanism of which free radicals are involved. Berry fruits are good sources of antioxidants consumed either in fresh or in processed forms because of great susceptibility of polyphenols to heat and other physicochemical processes.
