Kaempferol Glycosides Research Articles

Geographic Variation in the Chemical Composition and Antioxidant Properties of Phenolic Compounds from Cyclocarya paliurus (Batal) Iljinskaja Leaves.

Cyclocarya paliurus has been widely used as an ingredient in functional foods in China. However, the antioxidant properties of phenolic compounds and the effect of the plant origin remain unclear. The present study evaluated the geographical variation of this plant in term of its phenolic composition and antioxidant activities based on leaf materials collected from five regions. high-performance liquid chromatography (HPLC) analysis showed that there are three major components, quercetin-3-O-glucuronide, kaempferol-3-O-glucuronide, and kaempferol-3-O-rhamnoside, and their contents varied significantly among sampling locations. The investigated phenolic compounds showed substantial antioxidant activities, both in vitro and in vivo, with the highest capacity observed from Wufeng and Jinzhongshan. Correlation analysis revealed that quercetin and kaempferol glycosides might be responsible for the antioxidant activities. Our results indicate the importance of geographic origin, with sunny hours and temperature as the main drivers affecting the accumulation of C. paliurus phenolics and their antioxidant properties.

Protective effects of dietary kaempferol glycoside components from unripe soybean (Edamame, Glycine max L. Merrill. 'Jindai') leaves and their serous metabolite on carbon tetrachloride-induced liver injury mice.

The study investigated the protective effects of kaempferol galactoside (KG) components in mice, which were separated from Jindai soybean leaves (JDL) and mainly composed by two kaempferol galactosides. Further, KG-related metabolites in serum of mice were identified by Tof-MS. Results showed that both JDL and KG prevented the CCl4-induced increases in serum aspartate aminotransferase and serum alanine aminotransferase. Additionally, mice treated with KG had significantly decreased TBARS and TNF-alpha levels, compared to CCl4-treated mice. Serous analysis showed that kaempferol, glucuronidated kaempferol and methylated kaempferol with a glucuronic acid moiety were identified in the serum of mice fed unripe soybean leaves or kaempferol galactosides isolated from the leaves. The results indicated that kaempferol 3-O-galactoside connected to other glycosides via galactose might be hydrolyzed in the gastro-intestinal tract and/or epithelium cells to release kaempferol, followed by glucuronidation and/or methylation in the liver to contribute to a reduction in liver injury. The use of raw leaves containing kaempferol galactosides as food materials may contribute to a reduction in oxidation-related diseases.

Bread Enriched With Legume Microgreens and Leaves-Ontogenetic and Baking-Driven Changes in the Profile of Secondary Plant Metabolites.

Flavonoids, carotenoids, and chlorophylls were characterized in microgreens and leaves of pea (Pisum sativum) and lupin (Lupinus angustifolius) as these metabolites change during ontogeny. All metabolites were higher in the leaves for both species. Acylated quercetin and kaempferol sophorotrioses were predominant in pea. Genistein and malonylated chrysoeriol were predominant in lupin. Further, the impact of breadmaking on these metabolites using pea and lupin material of two ontogenetic stages as an added ingredient in wheat-based bread was assessed. In “pea microgreen bread” no decrease of quercetin was found with regard to the non-processed plant material. However kaempferol glycosides showed slight decreases induced by the breadmaking process in “pea microgreen bread” and “pea leaf bread.” In “lupin microgreen bread” no decrease of genistein compared to the non-processed plant material was found. Chrysoeriol glycosides showed slight decreases induced by the breadmaking process in “lupin microgreen bread” and “lupin leaf bread.” In all breads, carotenoids and chlorophylls were depleted however pheophytin formation was caused. Thus, pea and lupin microgreens and leaves are suitable, natural ingredients for enhancing health-promoting secondary plant metabolites in bread and may even be used to tailor bread for specific consumer health needs.

The maize secondary metabolism glycosyltransferase UFGT2 modifies flavonols and contributes to plant acclimation to abiotic stresses

Nowadays, the plant family 1 glycosyltransferases (UGTs) are attracting more and more attention since members of this family can improve the properties of secondary metabolites and have significantly enriched the chemical species in plants. Over the past decade, most studies on UGTs have been conducted in Arabidopsis thaliana and they were proved to play diverse roles during the plant life cycle. The Zea mays (maize) GT1 family comprises a large number of UDP-glycosyltransferase (UGT) members. However, their enzyme activities and the biological functions are rarely revealed. In this study, a maize flavonol glycosyltransferase, UFGT2, is identified and its biological role is characterized in detail. The UFGT2 enzyme activity, the flavonol and glycoside levels in planta were examined by high- performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). The functions of UFGT2 in modifying flavonols, mediating flavonol accumulation and improving stress tolerance were analysed using two ufgt2 mutants and transgenic arabidopsis plants. By in vitro enzyme assay, the maize UFGT2 was found to show strong activity towards two flavonols: kaemferol and quercetin. Two ufgt2 knockout mutants, Mu689 and Mu943, exhibited obvious sensitivity to salt and drought stresses. The endogenous quercetin and kaempferol glycosides, as well as the total flavonol levels were found to be substantially decreased in the two ufgt2 mutants, with declined H2O2-scavenging capacity. In contrast, ectopic expression of UFGT2 in arabidopsis led to increased flavonol contents and enhanced oxidative tolerance. Moreover, expression of typical stress-related genes in arabidopsis and maize were affected in UFGT2 overexpression plants or knockout mutants in response to abiotic stresses. UFGT2 was also transferred into the arabidopsis ugt78d2 mutant and it was found to recover the deficient flavonol glycoside pattern in the ugt78d2 mutant, which confirmed its catalysing activity in planta. It is demonstrated in our study that a maize glycosyltransferase, UFGT2, involved in modifying flavonols, contributes to improving plant tolerance to abiotic stresses.

A new method to prepare and redefine black tea thearubigins

Thearubigins (TRs) are the major components of black tea, which are formed during the fermentation reactions. Although anti-inflammatory and anti-cancer activities of TRs have been reported, the prepared TRs according to the literature methods still contain many floating peaks. It is puzzling whether the observed activities are from TRs or these floating peaks. Thus, it is urgent to develop a method to prepare pure TRs and redefine them. In the present study, we developed a new method, the combination of caffeine precipitation and Sephadex LH-20 column chromatography, to prepare pure TRs. The floating peaks on the hump of the crude TRs were removed, and pure TRs were prepared. The chemical profile of the floating peaks was established using LC/MS, and the major compounds in this fraction were identified as apigenin glycosides, quercetin glycosides, kaempferol glycosides, theaflavins, theasinensin, and galloylglucoses based on the analysis of their tandem mass spectra and in comparison with literature data. This study will pave the way to further study the chemistry and biological activities of TRs and the health effects of black tea consumption.

Flavonols from Annona coriacea Mart. (Annonaceae)

Annona is one of the largest genus of Annonaceae. Flavonol derivatives have the major occurrence in the family and in Annona. Glycosides of quercetin, kaempferol and isorhamnetin have been isolated and identified more frequently than any other flavonols. Annona coriacea Mart. is a perennial shrub native to the Brazilian savanna. The species has some acetogenins, alkaloids, diterpenes, polyphenols, flavonoids and volatile compounds already identified. We isolated 11 flavonols from A. coriacea leaves: 1 - quercetin-3-O-β-(6″-O-β-glucosyl)-glucoside (quercetin-3-O-gentiobioside), 2 - quercetin-3-O-β-(6″-O-α-rhamnosyl)-galactoside (quercetin-3-O-robinobioside), 3 - quercetin-3-O-β-(6″-O-α-rhamnosyl)-glucoside (rutin), 4 - quercetin-3-O-β-galactoside (hyperin), 5- quercetin-3-O-β-glucoside (isoquercitrin), 6 - kaempferol-3-O-β-(6″-O-α-rhamnosyl)-galactoside (biorobin), 7 - kaempferol-3-O-β-(6″-O-α-rhamnosyl)-glucoside (nicotiflorin), 8 - isorhamnetin-3-O-β-(6″-O-α-rhamnosyl)-galactoside (keioside), 9 - isorhamnetin-3-O-β-(6″-O-α-rhamnosyl)-glucoside (narcissin), 10 - isorhamnetin-3-O-β-galactoside (cacticin), 11 - isorhamnetin-3-O-β-glucoside. Quercetin derivatives were predominant, followed by isorhamnetin and kaempferol ones. All flavonols, except 3, have never been described in A. coriacea. Compound 10 was isolated only once in another species of the family. Compounds 8 and 9 are described for the first time in Annonaceae. The occurrence of flavonol derivatives as the main flavonoids could confirm that the family represents a basal evolutionary state.

Analysis of flavonoid glycosides with potential medicinal properties on Bauhinia uruguayensis and Bauhinia forficata subspecies pruinosa.

Several Bauhinia species are widely used in Southern South America in the treatment of infections, pain and several diseases including diabetes. Flavonoid compounds based on quercetin and kaempferol glycoside derivatives are believed to be responsible for their therapeutic properties. To investigate this, we have studied two native species from Argentina: B. uruguayensis (BU) and B. forficata subsp. pruinosa (BF). We have analyzed the major polyphenol components in hydro-methanolic extracts of leaves, by high performance liquid chromatography tandem mass spectrometry. Chromatographic analysis yielded five main compounds in BF, corresponding to rutinosides and rhamnosides derivatives of kaempferol and quercetin, which are considered chemotaxonomic markers and responsible for antioxidant activity. The presence of kaempferitrin, an antidiabetic agent, has been confirmed. In extracts of BU, four major compounds were identified as rhamnosides and galloyl derivates from quercetin and kaempferol. One of these compounds, quercitrin-3-rhamnoside may confer anti-inflammatory and analgesic properties to BU extracts.

Qualitative and quantitative analysis of flavonoids from 12 species of Korean mulberry leaves

The total flavonoids in leaves of 12 varieties of Korean mulberry (Morus alba L.) were determined. Seventeen flavonoids were isolated and analyzed using ultra-performance liquid chromatography coupled with diode array detection and quadrupole time-of-flight mass spectrometry (UPLC–DAD–QTOF/MS). To determine the flavonoid contents, HPLC analysis was performed on these 17 flavonoids. The total flavonoid contents of the 12 varieties of mulberry leaves ranged from 748.5 to 1297.9 mg, with the highest obtained from the Cheong Su variety (1297.9 ± 112.0 mg). Among the 17 flavonoids analyzed, quercetin 3-O-rutinoside (rutin) and quercetin 3-O-glucoside (isoquercitrin) had highest contents in the Cheong Su variety. Furthermore, the Dae Dang Sang variety gave the highest quercetin 3-O-rutinoside (rutin) content among the mulberry leaves investigated, at 425.5 ± 45.9 mg. Major flavonols from Dae Dang Sang were detected by UPLC–DAD–QTOF/MS. A total of 17 flavonoid compound peaks were identified in the analysis time range of 5–40 min, all of which were kaempferol and quercetin glycosides. Seven of the 17 compounds identified in mulberry leaves were unknown.

Characterization of Various Color Parameters (Anthocyanins and Flavonols) of Leaves and Flowers in Different Autochthonous Genotypes of Cyclamen purpurascens

Common cyclamen (Cyclamen pururascens Mill.) is a very interesting species not only for various breeding programs but also as an ornamental plant. The plants possess interesting floral and foliage characteristics, nice fragrances, and a very useful flavonol profile. The last is very important from the point of view of protecting against diseases and physiological disorders. Twenty-two different genotypes originating from different regions in Slovenia were analyzed in detail, based on their floral and foliage characteristics. Anthocyanin and flavonol contents were determined using high-performance liquid chromatography (HPLC)-photodiode array-mass spectrometry (MS). Color characteristics were colorimetrically evaluated separately for petals and leaves. In terms of color measurements, significant differences among the sites of origin were shown with parameters a* and L* when petals were analyzed, and with parameter a* when leaves were analyzed. The pH of petal sap stayed within the acid range, ranging from 3.96 to 4.82. Five different anthocyanins (malvidin-3,5-diglucoside, cyanidin-3-neohesperidoside, delphinidin-3-glucoside, delphinidin-3,5-diglucoside, and delphinidine-3-rutinoside) were analyzed in flowers, and this is the first report of delphinidin metabolites naturally present in common cyclamen genotypes. In relation to plant leaves, malvidin-3,5-diglucoside, malvidin-3-rutinoside, malvidin-3-glucoside, cyanidin-3-neohesperidoside, and peonidin-3-neohesperidoside were measured. Fifteen different flavonols were determined in common cyclamen flowers and 10 different flavonols in common cyclamen leaves. Various glycosides of quercetin, myricetin, and kaempferol were analyzed, as well as isorhamnetin-3-rutinoside, laricitin-3-rutinoside, and neohesperidin. The floral and foliage characteristics of the genotypes (physical and chemical) were mainly affected by the environmental conditions of the locality of origin of the genotypes (annual disposition of temperature and precipitation, structure of the soil, etc.).

Phytochemical study, antioxidant and cytotoxic activities of Brassica rapa L. leaves extract and its silver nanoparticles

Abstract Chemical constituents, antioxidant activities and cytotoxic effects of the 70% aqueous ethanolic extract of Brassica rapa L.(six fractions F1-6) of (BRE) were investigated. Its chromatographic, chemical and spectral analysis detected the existence of a new natural isorhamnetin glycosides namely; isorhamnetin 3-O-β-D-glucopyranosyl(1→2)-α-L-rhamnopyranosyl(1→2)-β-D-glucopyranoside (L2) together with fifteen known flavonoid compounds; five of the type kaempferol glycosides, four of quercetin glycosides, three of isorhamnetin glycosides and three aglycones. Silver nanoparticles of the ethanolic extract were also prepared which gave nanoparticles less than 20 nm.The two extracts (ethanolic extract and its nanoparticles) were evaluated for their potential cytotoxicity and as an antioxidant which showed that, the highest antioxidant extract was NBRE followed by BRE. The BRE and its NBRE were evaluated against HELA cells (human Cervical cancer cell line) and M-NFS-60 cells (human Mouse Myelogenous Leukemia carcinoma) with Doxorubicin as standard drug which NBRE gave high activity for both two cell line.

Postharvest changes in the phenolic profile of watercress induced by post-packaging irradiation and modified atmosphere packaging

The effects of γ-ray irradiation and modified atmosphere packaging (MAP) on watercress (Nasturtium officinale R. Br.) phenolic compounds were evaluated after 7-day storage at 4 °C. Irradiation doses of 1, 2 and 5 kGy were tested, as well as vacuum-packaging and MAP enriched with 100% N2 and Ar. A non-irradiated, air-packaged control was included in all experiments. p-Coumaric acid was the most abundant compound in fresh watercress, followed by quercetin-3-O-sophoroside and isorhamnetin-O-hydroxyferuloylhexoside-O-hexoside. Four kaempferol glycoside derivatives were identified for the first time in this species. In general, flavonoids predominated over phenolic acids. Samples stored under vacuum and irradiated at 2 kGy revealed lower phenolic levels. Ar-enriched MAP and control conditions preserved the initial phenolic content. The 5 kGy dose also maintained concentrations of flavonoids and total phenolic compounds, but increased the phenolic acids content. Additionally, flavonoids were found strongly correlated to DPPH scavenging activity and β-carotene bleaching inhibition capacity.

Chemical composition of the edible flowers, pansy (Viola wittrockiana) and snapdragon (Antirrhinum majus) as new sources of bioactive compounds

The nutritional composition - including total and individual phenolic compounds, carotenoids, and the antioxidant capacity – of two commercially available edible flowers, pansy and snapdragon, was studied. The edible flowers did not differ in their carbohydrates, fat, or ash contents, or in total energy, but pansy had higher values of moisture, protein, and total dietary fiber than snapdragon. Phenolic compounds were more abundant in pansy than in snapdragon, and flavonoids were the major compounds, followed by anthocyanins. The phenolic profile of pansy included flavonols, such as quercetin and isorhamnetin glycosides, flavones, such as apigenin glycosides, and anthocyanins, such as cyanidin and delphinidin glycosides; in snapdragon it included flavonol glycosides (e.g. quercetin and kaempferol glycosides) and anthocyanins, such as cyanidin and pelargonidin glycosides. The contents of total carotenoids were 146 and 29 µg/mg for pansy and snapdragon, respectively, and lutein was the dominant compound.

Phytochemical analysis and assessment of antioxidant, antimicrobial, anti-inflammatory and cytotoxic properties of Tetraclinis articulata (Vahl) Masters leaves

Tetraclinis is an unexplored genus recognized for its great bioactive potential that could be explored as a medicinal herb. The aim of this study was to evaluate the antioxidant, antibacterial, anti-inflammatory and cytotoxic properties of the aqueous crude extract and subsequent organic fractions of the Algerian medicinal plant T. articulata. Moreover, polyphenols were also fully profiled by liquid chromatography with diode-array detection coupled to electrospray ionization in tandem with mass spectrometry (LC–DAD–ESI–MSn). The analysis of the obtained results show that B-type (epi)catechin dimer and catechin were the most abundant phenolic compounds present among the nine different flavonoids identified such as: ((epi)catechin, myricetin, quercetin and kaempferol glycoside derivatives). The concentration of phenolic compounds in the ethyl acetate fraction (93.1 mg/g extract) was higher than the one of the aqueous extract (21.2 mg/g extract) and butanol fraction (43.87 mg/g extract). Furthermore, the ethyl acetate fraction revealed the strongest bioactive properties, revealing the lowest EC50/GI50 values: anti-inflammatory (EC50, 129.67 μg/mL), cytotoxicity against human tumor cell lines (GI50, 59–189 μg/mL), antibacterial (MIC, 0.625–10 mg/mL); and especially the antioxidant capacity (EC50 values lower than 12.7 μg/mL), even higher than the standard (Trolox). The results showed a great bioactive potential for this species, with a significant contribution of flavonoid compounds, which makes it an interesting matrix in the development of novel pharmaceutical formulations.

Phytochemical profile and antioxidant activity of caper berries (Capparis spinosa L.): Evaluation of the influence of the fermentation process

In this work, we report the phytochemical profile and antioxidant activity of caper berries (Capparis spinosa L.) before and after a fermentation process. The phytochemical profiles were evaluated by high-performance liquid chromatography with UV and electrospray ionization mass spectrometry detection (HPLC-DAD-ESI-MSn). Twenty-one compounds were characterized, and seven of them quantified. The main component of non-fermented berries was glucocapparin, which was degraded upon the fermentation process. Most of the compounds were quercetin and kaempferol glycosides, epicatechin, and proanthocyanidins. The main differences observed upon the fermentation process were a decrease in epicatechin concentration, the hydrolysis of quercetin glycosides, and the degradation of glucosinolates. Total phenolic and flavonoid contents, as well as the antioxidant activities by the in vitro antioxidant assays DPPH and ABTS+, were determined, observing that the values were slightly higher after the fermentation process.

Inhibition of α-glucosidase and α-amylase by flavonoid glycosides from Lu'an GuaPian tea: molecular docking and interaction mechanism.

Green tea may favorably modulate blood glucose homeostasis, and regular consumption of green tea can prevent the development of type 2 diabetes mellitus. In this study, α-glucosidase and α-amylase inhibitory effects of the novel acylated flavonol tetraglycoside (camellikaempferoside C, 1) and 14 other flavone and flavone glycosides (FGs) isolated from Lu'an GuaPian (Camellia sinensis L.O. Kuntze) were evaluated. The kaempferol monoglycoside (15) showed inhibitory activity against α-glucosidase with IC50 at 40.02 ± 4.61 μM, and kaempferol diglycoside (13) showed α-amylase inhibition with IC50 at 0.09 ± 0.02 μM. Further, inhibitory mechanisms of FGs 15 and 13 were studied by molecular docking analysis and fluorescence spectrometry. Molecular docking suggested that FG 15 interacted with α-glucosidase mainly by hydrogen bonding, which was the same interaction force between FG 13 and α-amylase. Intrinsic fluorescence of α-glucosidase and α-amylase was quenched by 15 and 13, respectively, through a static quenching mechanism. The spontaneous formation of 15-α-glucosidase and 13-α-amylase complexes was driven by van der Waals forces and hydrogen bonding. The present study provides new insight into the potential application of Lu'an GuaPian green tea as a functional food ingredient to regulate postprandial hyperglycemia through inhibition of α-glucosidase/α-amylase by FGs, particularly the mono- and di- glycosides of kaempferol.

Rhamnetin Glycosides from the Genus Spiraea

Rhamnetin (7-O-methylquercetin, 1) and its glycosides were found for the first time in the genus Spiraea (Rosaceae) during chromatographic studies of representatives from the subgenus Protospiraea. Leaves of S. salicifolia yielded 1, rhamnetin-3-O-β-D-glucopyranoside (2), and two new flavonoids 3 and 4 that were identified by UV, IR, and NMR spectroscopy and mass spectrometry as rhamnetin-3-O-(6″-O-p-coumaroyl)-β-D-glucopyranoside (spiraearhamnin A, 3) and rhamnetin-3-O-(6″-O-caffeoyl)-β-D-glucopyranoside (spiraearhamnin B, 4). Leaves of S. betulifolia and S. betulifolia var. aemiliana afforded 1 and 2 and glycosides of kaempferol, quercetin, and isorhamnetin. Species of the subgenus Metaspiraea (S. alpina, S. chamaedryfolia, S. dahurica, S. hypericifolia, and S. media) did not contain 1 or its derivatives.

Topical or oral treatment of peach flower extract attenuates UV-induced epidermal thickening, matrix metalloproteinase-13 expression and pro-inflammatory cytokine production in hairless mice skin.

BACKGROUND/OBJECTIVESUltraviolet radiation (UV) is a major cause of skin photoaging. Previous studies reported that ethanol extract (PET) of Prunus persica (L.) Batsch flowers (PPF, peach flowers) and its subfractions, particularly the ethylacetate (PEA) and n-butanol extracts (PBT), have potent antioxidant activity and attenuate the UV-induced matrix metalloproteinase (MMP) expression in human skin cells. In this study, we investigated the protective activity of PPF extract against UV-induced photoaging in a mouse model.MATERIALS/METHODSHairless mice were treated with PET or a mixture of PEA and PBT either topically or orally along with UV irradiation. Histological changes and biochemical alterations of mouse skin were examined. Major phenolic compounds in PPF extract were analyzed using an ACQUITY UPLC system.RESULTSThe overall effects of topical and oral treatments with PPF extract on the UV-induced skin responses exhibited similar patterns. In both experiments, the mixture of PEA and PBT significantly inhibited the UV-induced skin and epidermal thickening, while PET inhibited only the UV-induced epidermal thickening. Treatment of PET or the mixture of PEA and PBT significantly inhibited the UV-induced MMP-13 expression, but not typeⅠ collagen expression. Topical treatment of the mixture of PEA and PBT with UV irradiation significantly elevated catalase, superoxide dismutase (SOD) and glutathione-peroxidase (GPx) activities in the skin compared to those in the UV irradiated control group, while oral treatment of the mixture of PEA and PBT or PET elevated only catalase and SOD activities, but not GPx. Thirteen phytochemical compounds including 4-O-caffeoylquinic acid, cimicifugic acid E and B, quercetin-3-O-rhamnoside and kaempferol glycoside derivatives were identified in the PPF extract.CONCLUSIONSThese results demonstrate that treatment with PET or the mixture of PEA and PBT, both topically or orally, attenuates UV-induced photoaging via the cooperative interactions of phenolic components having anti-oxidative and collagen-protective activities.

Amentoflavone and Kaempferol Glycosides from the Aerial Parts of Cissampelos pareira

Aerial parts of Cissampelos pareira L. (Family: Menispermaceae), commonly known as “Batulpate” in Nepal, are used for the treatment of fever, indigestion and to stop bleeding after child birth. In this study, a biflavonoid, amentoflavone; and two kaempferol glycosides, kaempferol 3-O-b-D-glucopyranoside and kaempferol 3-O-b-D-glucuronopyranoside were isolated from 70% MeOH extract of the aerial parts. Structures of these compounds were elucidated on the basis of 1H- and 13C-NMR spectral data. To the best of our knowledge, it is the first report on the isolation of these compounds from a plant belonging to family Menispermaceae.Nepal Journal of Biotechnology. Dec. 2017 Vol. 5, No. 1:1-4

Antibacterial potential of the Cistus incanus L. phenolics as studied with use of thin-layer chromatography combined with direct bioautography and in situ hydrolysis

The main aim of this study was to detect and identify antibacterial components of fraction I derived from eleven commercial C. incanus herbal teas. Fraction I obtained by a well-established phytochemical protocol of a multi-step extraction was expected to contain flavonoid aglycons alone. Antibacterial profile of fraction I was demonstrated by means of thin-layer chromatography – direct bioautography (TLC-DB) using a Gram positive B. subtilis and a Gram negative A. fischeri strain. Six chromatographic zones of fraction I exhibited a well pronounced antibacterial potential. In qualitative terms, a good agreement was observed among chromatographic fingerprints and the corresponding bioautograms of the eleven samples. The compounds isolated from the six zones were analyzed by HPLC- diode array detector (DAD)-electrospray ionization (ESI)-MS. High numerical m/z values valid for certain constituents of these isolates suggested that some selected antibacterial components are, unexpectedly, flavonoid glycosides. In order to confirm this suggestion, three independent HPTLC methods (multi-development on amino phase and two two-dimensional developments on silica gel phase) were devised to in situ hydrolyze flavonoid glycosides and then separate and visualize the liberated glucose and some other building blocks of the zones’ components. Additionally, the sensitivity of glucose detection with p-aminobenzoic acid reagent was enhanced by paraffin. In that way, the presence of the kaempferol glycosides (and not only the aglycones alone) in fraction I was confirmed. Beside kaempferol, p-coumaric acid as a building block unit was shown by HPLC-DAD-MS analysis of the hydrolyzed isolates. Results proved apigenin, kaempferide and acylated kaempferol glycosides (cis- and trans-tiliroside and their conjugates with p-coumaric acid) to be antibacterial components of fraction I. Because isomers of the coumaric acid conjugated tiliroside were detected only in fraction I and not in the crude C. incanus extract, they are regarded as artifacts produced through fractionation.

Capillary electrophoresis as a fast and efficient alternative for the analysis of Urceola rosea leaf extracts

Urceola rosea, a plant whose leaves are used as food and for medical purposes, is a climbing liana found in many south-east Asian countries. Main polar compounds are flavonoids (kaempferol and quercetin glycosides) and phenolic acids. As an alternative to the established HPLC method their analysis by capillary electrophoresis is described for the first time. It was possible in <8min with a 25mM sodium tetraborate decahydrate solution with pH8.5, at a capillary temperature of 40°C and an applied voltage of 25kV. Up to five compounds could be quantified in different methanolic U. rosea extracts, which showed to be of variable composition; e.g. the content of total flavonoids ranged from 0.29 to 1.08%. In respect to quantitative results as well as validation parameters (e.g. R2≥0.994, recovery rates from 95.5 to 103.6%, inter-day precision≤4.5%) the CE method was well comparable to HPLC. However, in terms of required analysis time and environmental sustainability capillary electrophoresis is definitely advantageous.