Isorhamnetin Glycosides Research Articles

ИССЛЕДОВАНИЕ ФЛАВОНОИДОВ ГОМЕОПАТИЧЕСКОГО ЛЕКАРСТВЕННОГО РАСТИТЕЛЬНОГО СЫРЬЯ ПОДСНЕЖНИКА ВОРОНОВА (GALANTHUS WORONOWII LOSINSK.) И ПОДСНЕЖНИКА БЕЛОСНЕЖНОГО (GALANTHUS NIVALIS L.) МЕТОДОМ УЭЖХ/ФДМ/МС

This article presents data describing flavonoid composition of Galanthus woronowii Losinsk. and Galanthus nivalis L. homeopathic crude herbal drugs (HomCHD) harvested at the Botanical Garden of I.M. Sechenov First Moscow State Medical University. The studies were conducted with a chromatograph «ACQUITY ™ UPLC TQD» (Waters, USA) equipped with two types of detectors: photodiode array (Waters PDA, USA), triple quadrupole mass spectrometry (Waters ACQUITY Triple Quadrupole Detector, USA). Separation was performed by a column of «Acquity UPLC BEH» C18, 2,1×150 mm. Gradient elution mode was formed by mixing mobile phase A (water / acetonitrile / formic acid – 95 : 5 : 0.1). and B (acetonitrile / formic acid – 100 : 0.1). Flow rate of mobile phase is 0,3 mL / min. For the first time ever flavonol glycosides were determined by UPLC/PDA/MS/MS method in ethanol extracts from HomCHD of snowdrops. Glycosides of quercetin and isorhamnetin are presented in Galanthus woronowii , glycosides of quercetin and kaempferol are presented in Galanthus nivalis . The difference in the aglycone component composition of two snowdrops species was established, this difference will be used for standardization procedures of HomCHD.

Fruit Phenolic Composition of Different Elderberry Species and Hybrids.

The aim of this study was to investigate a detailed composition and content of phenolic compounds in fruits of 4 elderberry species (Sambucus nigra, S. cerulea, S. ebulus, and S racemosa) and 8 interspecific hybrids. Hydroxycinnamic acids (HCAs) represented the major share of phenolics in analyzed elderberries; caffeoylquinic and p-coumaroylquinic acids were most abundant. Flavanols (catechin, epicatechin, and different procyanidins) were the second major phenolic group detected in range from 2% to 30% of total analyzed phenolics. From the group of flavonols, 13 different quercetin glycosides, 7 kaempferol glycosides, and 8 isorhamnetin glycosides have been quantified. Rutin was the major flavonol in all studied genotypes. S. ebulus was characterized by the highest level of total HCAs, catechin, epicatechin, and most flavonols. Some elderberry hybrids, for example JA × RAC, CER × NI, and JA × (JA × NI), are perspective for further studies because they have high content of phenolic compounds. The results of research could contribute to breed cultivars, which may prove interesting for food-processing industries. Different levels of phenolic compounds have been measured in fruit of analyzed elderberry species and interspecific hybrids. Natural evaluation of elderberry genetic resources, the identification of phenolic compounds, and assessment of their properties are of great interest to breeders and directly valid for pharmaceutical and food industry.

Flavonol profile of cactus fruits (Opuntia ficus-indica) enriched cereal-based extrudates: Authenticity and impact of extrusion

In previous studies, it was hypothesized that isorhamnetin glycosides are the dominant flavonol derivatives occurring in the peels and cladodes of cactus Opuntia ficus-indica fruits and might be used as markers for analyzing the authenticity of food products containing (whole) cactus fruits or cladodes. In the present work, use of the whole yellow-orange fruit from cactus O. ficus-indica as an ingredient of rice- and corn-based snacks was evaluated. The impact of extrusion cooking on the flavonol profile was characterized in rice- and corn-based extruded products fortified with a freeze-dried preparation from the whole cactus fruit. HPLC analysis showed that the flavonol profile of cactus O. ficus-indica consisted of five prominent isorhamnetin glycosides with a concentration of 148.9μg/100mg dw. In contrast, the rice or corn grits used in the present study did not contain any flavonol at all. The freeze-dried fruit was added in different ratios (0, 2, 6, and 10%) to the rice or corn grits prior to the extrusion process. Analysis of the final extrusion products showed that flavonol profiles from the fortified rice or corn products, even at the lowest level of addition (2%), were similar to the original profile of the fruit before processing. Furthermore, the total flavonol content in extruded products was not significantly affected by extrusion cooking. This study showed that the unique flavonol profile of fruits from cactus O. ficus-indica might serve as a biochemical marker for the evaluation of the authenticity of products made from whole cactus fruit or the fruit's peel.

In vivo anti-inflammatory effects of isorhamnetin glycosides isolated from Opuntia ficus-indica (L.) Mill cladodes

Opuntia ficus-indica (L.) Mill [OFI] has been traditionally used to reduce inflammation. This plant possesses a varied composition of phytochemicals such as flavonoids. The aim of this investigation was to study the anti-inflammatory effects of an OFI extract and two isolated isorhamnetin glycosides using an air-pouch inflammation model. Isorhamnetin glycosides were isolated by semi-preparative chromatography and identified with LC/MSD TOF. Male Wistar rats were divided into five groups (n=6) receiving isorhamnetin-3-O-glucosyl-rhamnosyl-rhamnoside (IGRR), isorhamnetin-3-O-glucosyl-rhamnoside (IGR), OFI extract, indomethacin or vehicle intraperitoneally. IGR showed the best potential to decrease cell infiltration, mainly neutrophils (51.8±10.9%). IGRR and OFI extract inhibited the nitric oxide production (IGRR: 81.4%; OFI extract: 77.2%) and cyclooxygenase-2 activity (IGRR: 76.3%; OFI extract: 77.7%). OFI extract showed the highest inhibition of tumor necrosis factor (TNF)-α (85.2%) and interleukin (IL)-6 (53.0%). Results showed that OFI extract and isorhamnetin glycosides possess anti-inflammatory potential. IGRR showed better effect than IGR suggesting that the glycosylation profile affects the bioactivity.

Variability in Foliar Phenolic Composition of Several Quercus Species in Northern Mexico

Quantitative and qualitative composition of the foliar phenolic compounds were investigated in 81 individual specimens of several white oak species (Quercus spp.). The trees were growing in twelve locations in Durango, Mexico. The phenol profiles were determined by HPLC-DAD and a Folin-Ciocateu procedure. The results revealed that: (i) the foliar phenol profiles of all species analysed were complex and formed by 6 to 30 compounds, (ii) the flavonols mostly quercetin glycoside, isorhamnetin glycoside, kaempferol glycoside and phenolic acids were the main identified compounds, (iii) there was a high intra and inter-specific variability in the foliar phenol profiles both at the quantitative and qualitative levels, and (iv) the foliar phenol profiles indicated a slight species-specific tendency for phenols to be accumulated, although this was not clearly distinguished. Significant differences (P < 0.05) in the content and composition of the foliar flavonoids between species were observed due to the large environmental and soil conditions variability between localities.

Two Isorhamnetin Glycosides from Arthrocnemum glaucum that Inhibit Adipogenesis in 3T3-L1 Adipocytes

In our search for bioactive compounds from North African plants [1, 2], we found that the Tunisian medicinal plant Arthrocnemum glaucum Delile inhibited adipogenesis in 3T3-L1. A. glaucum, which belongs to the Chenopodiaceae, is a densely branched robust plant that grows wild in the Sahara Desert of Tunisia, especially in the Mediterranean Coastal region. It was previously reported that some alkaloids and some sterols were isolated from A. glaucum [3–6]. In this research, the bioassay-guided fractionation of this plant implied that the bioactive components are two isorhamnetin glycosides, isorhamnetin-3-O-[apiosyl(1 6)]glucosyl-7-O-rhamnoside (1) and isorhamnetin-3-O-rutinoside (2). In this paper, we report the isolation and structure elucidation of the two isorhamnetin glycosides 1 and 2 from aerial parts of this plant and their antiadipogenesis activity. The aerial part of A. glaucum was collected at the Sahara Desert of Tunisia. The voucher specimen (TPM-20080401) is maintained at Alliance for Research on North Africa (ARENA), University of Tsukuba and Environmental Bioprocesses Laboratory at Biotechnology Center of Sfax. The leaves were dried in the shade at 25 C. The dried leaves of A. glaucum (100 g) were extracted with MeOH. The MeOH extracts were partitioned between EtOAc and H2O, and the H2O layer was partitioned with n-BuOH. The n-BuOH-soluble portion (1.33 g) was subjected to ODS column chromatography and purified by reversed-phase HPLC or gel-filtration HPLC to afford two known flavonol glycosides, isorhamnetin-3-O[apiosyl(1 6)]glucosyl-7-O-rhamnoside (1, 0.0085%) and isorhamnetin-3-O-rutinoside (2, 0.0027%). Structure elucidation of 1 and 2 was through spectroscopic data, mainly 1H and 13C NMR spectra and ESI-MS spectra. Full assignment of signals in the NMR spectra of 1 and 2 was confirmed by 2D NMR experiments (1H–1H COSY, NOESY, HMQC, and HMBC) and comparison with reported data [7, 8].

Topical anti-inflammatory effects of isorhamnetin glycosides isolated from Opuntia ficus-indica.

Opuntia ficus-indica (OFI) has been widely used in Mexico as a food and for the treatment of different health disorders such as inflammation and skin aging. Its biological properties have been attributed to different phytochemicals such as the isorhamnetin glycosides which are the most abundant flavonoids. Moreover, these compounds are considered a chemotaxonomic characteristic of OFI species. The aim of this study was to evaluate the effect of OFI extract and its isorhamnetin glycosides on different inflammatory markers in vitro and in vivo. OFI extract was obtained by alkaline hydrolysis of OFI cladodes powder and pure compounds were obtained by preparative chromatography. Nitric oxide (NO), cyclooxygenase-2 (COX-2), tumor necrosis factor- (TNF-) α, and interleukin- (IL-) 6 production were measured. NO production was tested in lipopolysaccharide-stimulated RAW 264.7 cells while in vivo studies were carried on croton oil-induced ear edema model. OFI extract and diglycoside isorhamnetin-glucosyl-rhamnoside (IGR) at 125 ng/mL suppressed the NO production in vitro (73.5 ± 4.8% and 68.7 ± 5.0%, resp.) without affecting cell viability. Likewise, IGR inhibited the ear edema (77.4 ± 5.7%) equating the indomethacin effects (69.5 ± 5.3%). Both IGR and OFI extract significantly inhibited the COX-2, TNF-α, and IL-6 production. IGR seems to be a suitable natural compound for development of new anti-inflammatory ingredient.

Effects of Preflowering Leaf Removal on Phenolic Composition of Tempranillo in the Semiarid Terroir of Western Spain

The effects of preflowering defoliation on the qualitative and quantitative composition of phenolic compounds in the grape skins of Tempranillo grapevines grown in a semiarid terroir of western Spain, Badajoz, were determined. Control vines were compared with defoliation carried out before flowering (ED) in 2009 and 2010. Forty-two phenolic compounds were identified and quantified in the grape skins, including anthocyanins, flavonols, flavanols (cathechin and epi-cathechin and the flavanol dimmers B1, B2, and B3), and hydroxycinnamic acids, as both simple and conjugated molecules. ED did not significantly alter the concentration of total anthocyanidins, although in 2009, 3-O-acylated monoglucosides and p-coumaroylglucoside forms were more abundant in this treatment. A nonsignificant tendency toward increased total flavanols due to defoliation treatment was observed. Leaf removal increased concentrations of flavonols (glycosides of myricetin, quercetin, kaempherol, and isorhamnetin), hydroxycinnamic acids, and stilbenes in season-specific ways. Preflowering leaf removal may contribute to increased concentrations of compounds that can form complexes with anthocyanins (copigments) and may thus improve wine color stability.

Induction of apoptosis in colon cancer cells treated with isorhamnetin glycosides from Opuntia ficus-indica pads.

(OFI) contains health-promoting compounds like flavonoids, being the isorhamnetin glycosides the most abundant. We evaluated the effect of OFI extracts with different isorhamnetin glycosides against two different human colon cancer cells (HT-29 and Caco2). The extracts were obtained by alkaline hydrolysis with NaOH at 40 °C during 15, 30 or 60 min. Tri and diglycosides were the most abundant isorhamnetin glycosides, therefore these compounds were isolated to compare their cytotoxic effect with the obtained from the extracts. The OFI extracts and purified isorhamnetin glycosides were more cytotoxic against HT-29 cells than Caco2 cells. OFI-30 exhibited the lowest IC50 value against HT-29 (4.9 ± 0.5 μg/mL) and against Caco2 (8.2 ± 0.3 μg/mL). Isorhamnetin diglycosides IG5 and IG6 were more cytotoxic than pure isorhamnetin aglycone or triglycosides when they were tested in HT-29 cells. Bioluminescent analysis revealed increased activity of caspase 3/7 in OFI extracts-treated cells, particularly for the extract with the highest concentration of isorhamnetin triglycosides. Flow cytometry analysis confirmed that OFI extract and isorhamnetin glycosides induced a higher percentage of apoptosis in HT-29 than in Caco2, while isorhamnetin was more apoptotic in Caco2. This research demonstrated that glycosilation affected antiproliferative effect of pure isorhamnetin glycosides or when they are mixed with other phytochemicals in an extract obtained from OFI.

Influence of cultivar and origin on the flavonol profile of fruits and cladodes from cactus Opuntia ficus-indica

Flavonols are hypothesized to be the most important polyphenolic antioxidants. This present study aimed at investigating flavonols in cactus Opuntia ficus-indica fruits from two Egyptian cultivars in comparison to three common Sicilian cultivars, and two further cultivars from South Africa. Besides, cactus O. ficus-indica cladodes from Egyptian cultivars have been investigated as well. HPLC–DAD analyses showed that cactus O. ficus-indica fruits and cladodes are mainly characterized by isorhamnetin glycosides. These flavonols were found only in the fruit's peel and the cladodes, but not in the pulp. However, all analyzed cultivars exhibited the same flavonol profile which might therefore serve as a chemical fingerprint with regard to genuineness of cactus O. ficus-indica fruits and cladodes or even food products containing whole cactus fruits as ingredients. The findings obtained have been confirmed both by enzymatic hydrolysis of flavonol glycosides following analysis of the aglycons and by HPLC–ESI-MSn. The concentration of total flavonols ranged from 2.2 to 4.1 and 6.3 to 7.6mg/g (dw) in the fruit peels and the cladodes, respectively. Further, fruit peels and cladodes exhibited high total phenolic contents and antioxidant activities compared to those of the fruit pulps. These investigations valorize cactus fruit's peel and cladode in comparison to fruit's pulp, and may further provide additional data for using flavonols in chemotaxonomic studies of cactus Opuntia spp. and authenticity of cactus O. ficus-indica products.

UHPLC/PDA–ESI/MS Analysis of the Main Berry and Leaf Flavonol Glycosides from Different Carpathian Hippophaë rhamnoides L. Varieties

Sea buckthorn (Hippophaë rhamnoides L.) is known to be rich in many bioactive compounds (such as vitamins, phenolics, carotenoids) important for human health and nutrition. Among the phenolics, berries and leaves contain a wide range of flavonols that are good quality and authenticity biomarkers. To compare the composition of the main flavonols of Romanian sea buckthorn berry and leaf varieties and to identify the specific biomarkers that contribute to sample differentiation among varieties. Six varieties of cultivated sea buckthorn (ssp. Carpatica) berries and leaves were analysed by UHPLC/PDA-ESI/MS. Berries and leaves contained mainly isorhamnetin (I) glycosides in different ratios. Whereas I-3-neohesperidoside, I-3-glucoside, I-3-rhamnosylglucoside, I-3-sophoroside-7-rhamnoside and free isorhamnetin were predominant for berries (out of 17 compounds identified), I-3-rhamnosylglucoside, I-3-neohesperidoside, I-3-glucoside, quercetin-3-pentoside, kaempferol-3-rutinoside, and quercetin-3-glucoside were predominant in leaves (out of 19 compounds identified). Berries contained, on average, 917 mg/100 g DW flavonol glycosides. Leaves had higher content of flavonol glycosides than berries, on average 1118 mg/100 g DW. The variation of the quantitative dataset analysed using principal component analysis accounted for 91% of the total variance in the case of berries and 73% in case of leaves, demonstrating a good discrimination among samples. Based on quantitative analysis, by principal component analysis, the flavonol derivatives can be considered as biomarkers to discriminate among varieties and to recognise specifically the berry versus leaf composition.

OPUNTIA FICUS-INDICA AND OPUNTIA MACRORHIZA: PROMISING SOURCES OF FLAVONOLS - COMPARISON BETWEEN CULTIVARS FROM DIFFERENT ORIGINS

Identification and quantification of flavonol glycosides in pulps and peels of Opuntia ficus-indica from different origins (Egypt, Sicily and South Africa) and Opuntia macrorhiza fruits were done using HPLC-DAD and HPLC-MS. In addition a gentle enzymatic hydrolysis of flavonol glycosides using commercial pectolytic enzymes was applied. Finally a comparison of antioxidant activities between all investigated matrices was carried out using electron paramagnetic resonance (EPR) spectroscopy. Results indicated that both, O. ficus-indica and O. macrorhiza, are characterized by high amounts of isorhamnetin glycosides (mainly isorhamnetin 3-O-rutinoside). O. ficus-indica showed the same profile of isorhamnetin glycosides in the peels of all origins. However, the isorhamnetins have not been detected in the pulps. In contrast, O. macrorhiza peels illustrated a different profile of isorhamnetin glycosides. The enzymatic hydrolysis of flavonol glycosides, produced only isorhamnetin as the only aglycon. Obtained results indicate that isorhamnetins could be considered as markers for the cactus pear fruits, or for adulteration of their processed products. Antioxidant activities of all investigated O. ficus-indica peels were higher than those of all pulps.

Phytochemical investigation on Atriplex halimus L. from Sardinia

In this study, we reported the phytochemical composition of the aerial parts of Atriplex halimus L. collected from Sardinia. This species is a halophytic shrub, typical of the Mediterranean Basin. Four new glycosylated flavonoids were isolated and their structures were elucidated on the basis of 1D, 2D NMR and MS spectra as 3′,5′-dimethoxymyricetin-3-O-β-d-xylopyranosyl-7-O-fucopyranosyl-(1 → 3)-β-d-glucopyranoside (1), 3′-methoxyquercetin-7-O-β-d-fucopyranosyl-(1 → 3)-β-d-glucopyranosyl-3-O-β-xylopyranosyl-(1 → 4)-β-xylopyranoside (2), 3′-methoxyquercetin-7-O-α-l-rhamnopyranosyl-3-O-α-arabinofuranosyl-(1 → 6)-β-d-glucopyranoside (3) and 3′,5′-dimethoxymyricetin-7-O-fucopyranosyl-(1 → 3)-β-d-glucopyranoside (4). LC-MSn analysis on the extract revealed the presence of other myricetin, quercetin, isorhamnetin glycosides, simple phenolic acids and esters.

Identification and quantification of flavonols, anthocyanins and lutein diesters in tepals of Crocus sativus by ultra performance liquid chromatography coupled to diode array and ion trap mass spectrometry detections

Ultra performance liquid chromatography coupled to diode array detection (UPLC DAD) and ion trap mass spectrometry with either electrospray ionization (ESI-MSn) or atmospheric pressure chemical ionization (APCI-MSn) interface were used to investigate flavonols, anthocyanins and lutein diesters in tepals from Crocus sativus. Extraction by methanol/water (1:1, v/v) containing 1% hydrochloric acid was selected as the optimal solvent mixture for a quantitative extraction of flavonols and anthocyanins. A UPLC method for separation of nineteen flavonols: kaempferol, quercetin and isorhamnetin glycosides as mono-, di- or tri-glycosides and five anthocyanins reported as delphinidin, petunidin and malvidin glycosides was achieved. Kaempferol glycosides were the major flavonols (84.0% of total flavonol content) in C. sativus tepals, the main compound was kaempferol 3-O-sophoroside. Isorhamnetin 3-O-sophoroside, kaempferol 3-O-rutinoside and quercetin 3-O-glucoside 7-O-rhamnoside in C. sativus tepals were newly identified. Anthocyanins were quantified for the first time in C. sativus tepals (4804±233μgg−1 DW), the main anthocyanin identified was delphinidin 3,7-O-diglucoside. For the first time, (E) and (Z) isomers of lutein diesters with lauric, myristic, palmitic and stearic acids were found in C. sativus and characterized by UPLC DAD/APCI-MS. A gradient programme consisting of methanol/water (8:1, v/v) and ethyl acetate was developed for their qualitative and quantitative analyses. Lutein diesters’ content (21.46±0.98mg 100g−1 DW) in tepals from C. sativus was comparable to food products, lutein diesters represented 69% of the total lutein diesters’ content.

An Optimized Method for Analysis of Phenolic Compounds in Buds, Leaves, and Fruits of Black Currant (Ribes nigrum L.)

Although the fruits are the economic driver for the black currant industry, the buds and leaves are excellent sources of beneficial phenolic compounds that may contribute to the future value of the crop. In this study, extraction of phenolic compounds for different parts of the black currant plant was optimized, and an efficient method for their separation by HPLC was developed. This allowed the simultaneous quantification of a range of hydroxycinnamic acids, flavan-3-ols, flavonols, and anthocyanins by DAD following their identification by HPLC-ESI-MS(n). A total of 23 compounds were detected in the buds, 22 of which were found in fruit and leaves. To the best of our knowledge, this is the first report of flavonol glycosides of quercetin, myricetin, isorhamnetin, and kaempferol along with hydroxycinnamic acids such as neo-chlorogenic acid and chlorogenic acid in the buds. Additionally, we provide the first evidence of kaempferol-3-O-rutinoside in black currant leaves. This approach offers avenues for superior combined compositional identification and cultivar selection targeted at the generation of polyphenol-rich products derived from the whole crop and not just the fruit.

HPLC–MSn identification and quantification of flavonol glycosides in 28 wild and cultivated berry species

Berries and red fruits are rich dietary sources of polyphenols with reported health benefits. More than 50 different flavonols (glycosides of quercetin, myricetin, kaempferol, isorhamnetin, syringetin and laricitrin) have been detected and quantified with HPLC–MSn in fruits of blueberry, bilberry, cranberry, lingonberry, eastern shadbush, Japanese wineberry, black mulberry, chokeberry, red, black and white currants, jostaberry, red and white gooseberry, hardy kiwifruit, goji berry, rowan, dog rose, Chinese and midland hawthorn, wild and cultivated species of blackberry, raspberry, strawberry and elderberry. The phenolic constituents and contents varied considerably among the analyzed berry species. Elderberry contained the highest amount of total flavonols (450–568mgkg−1 FW), followed by berry species, containing more than 200mgkg−1 FW of total: chokeberry (267mgkg−1), eastern shadbush (261mgkg−1), wild grown blackberry (260mgkg−1), rowanberry (232mgkg−1), american cranberry (213mgkg−1) and blackcurrants (204mgkg−1). Strawberry (10.5mgkg−1) and white currants (4.5mgkg−1) contained the lowest amount of total flavonols. Quercetins represent the highest percentage (46–100%) among flavonols in most analyzed berries. In wild strawberry and gooseberry the prevailing flavonols belong to the group of isorhamnetins (50–62%) and kaempferols, which represent the major part of flavonols in currants (49–66%). Myricetin glycosides could only be detected in chokeberry, rowanberry and species from the Grossulariaceae, and Adoxaceae family and Vaccinium genus. Wild strawberry and blackberry contained from 3- to 5-fold higher total flavonols than the cultivated one.

EARLY DETECTION OF GRAPE PHYLLOXERA (DAKTULOSPHAIRA VITIFOLIAE FITCH) INFESTATION THROUGH IDENTIFICATION OF CHEMICAL BIOMARKERS

Principle components analysis (PCA) was used to assess the presence of phylloxera associated biomarker compounds in G1 phylloxera infested Vitis vinifera L. vines in the Yarra Valley, Victoria. High Performance Liquid Chromatography (HPLC) analysis showed strongly upregulated flavonoid secondary metabolites in 80% methanol:water vine leaf extracts with mass spectroscopy (MS) analysis yielding the identification of four flavonoid compounds: isorhamnetin glycoside, rutin, kaempherol glycoside and quercetin glycoside. Flavanoids and other phenolics are a common class of bioactive compounds that form part of the endogenous or induced biochemical defence mechanisms employed by plants to counter infectious pathogens and insect attack, among other functions. The specificity of these flavonoid compounds to phylloxera infestation is currently being validated through field and glasshouse-based trials against nutrient and water stress. Successful correlation of these compounds to phylloxera infestation would provide a platform for laboratory-based early detection, leading to more timely advice to viticulturalists, more rapid instigation of quarantine protocols and a great reduction in losses associated with late detections of phylloxera infestations.

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.

Identification of complex, naturally occurring flavonoid glycosides in kale (Brassica oleracea var. sabellica) by high‐performance liquid chromatography diode‐array detection/electrospray ionization multi‐stage mass spectrometry

Kale is a member of the Brassicaceae family and has a complex profile of flavonoid glycosides. Therefore, kale is a suitable matrix to discuss in a comprehensive study the different fragmentation patterns of flavonoid glycosides. The wide variety of glycosylation and acylation patterns determines the health-promoting effects of these glycosides. The aim of this study is to investigate the naturally occurring flavonoids in kale. A total of 71 flavonoid glycosides of quercetin, kaempferol and isorhamnetin were identified using a high-performance liquid chromatography diode-array detection/electrospray ionization multi-stage mass spectrometry (HPLC-DAD/ESI-MS(n)) method. Of these 71 flavonol glycosides, 27 were non-acylated, 30 were monoacylated and 14 were diacylated. Non-acylated flavonol glycosides were present as mono-, di-, tri- and tetraglycosides. This is the first time that the occurrence of four different fragmentation patterns of non-acylated flavonol triglycosides has been reported in one matrix simultaneously. In addition, 44 flavonol glycosides were acylated with p-coumaric, caffeic, ferulic, hydroxyferulic or sinapic acid. While monoacylated glycosides existed as di-, tri- and tetraglycosides, diacylated glycosides occurred as tetra- and pentaglycosides. To the best of our knowledge, 28 compounds in kale are reported here for the first time. These include three acylated isorhamnetin glycosides (isorhamnetin-3-O-sinapoyl-sophoroside-7-O-D-glucoside, isorhamnetin-3-O-feruloyl-sophoroside-7-O-diglucoside and isorhamnetin-3-O-disinapoyl-triglucoside-7-O-diglucoside) and seven non-acylated isorhamnetin glycosides.

Difference in chilling-induced flavonoid profiles, antioxidant activity and chilling tolerance between soybean near-isogenic lines for the pubescence color gene

Chilling tolerance is an important trait of soybeans [Glycine max (L.) Merr.] produced in cool climates. We previously isolated a soybean flavonoid 3' hydroxylase (F3'H) gene corresponding to the T locus, which controls pubescence and seed coat color. A genetic link between the T gene and chilling tolerance has been reported, although the exact underlying mechanisms remain unclear. Using the soybean near-isogenic lines (NILs) To7B (TT) and To7G (tt), we examined the relationship between chilling injury, antioxidant activity and flavonoid profiles associated with chilling treatment (15°C). Chilling injury was more severe in the second trifoliate leaves of To7G than in those of To7B. Hydrogen peroxide accumulation and lipid peroxidation were enhanced by chilling in To7G. Chilling-induced enhancement of antioxidant activity was more prominent in To7B than in To7G. High performance liquid chromatography analysis indicated that the contents of quercetin glycosides and isorhamnetin glycosides (3',4'-dihydroxylated flavonol derivatives) increase in the second trifoliate leaves of To7B after chilling treatment, whereas the same treatment increased kaempferol glycoside (4'-monohydroxylated flavonol derivatives) content in the corresponding leaves of To7G. Histochemical staining also demonstrated chilling-induced flavonoid accumulation. Microarray analysis and real-time reverse transcription-PCR demonstrated that the transcript levels of soybean F3'H are upregulated by chilling. The differences in chilling injury, antioxidant activity and flavonoid species between the two NILs support the notion that soybean F3'H affects chilling tolerance by increasing antioxidant activity via production of 3',4'-dihydroxylated flavonol derivatives.