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Flavonoid aglycons in foods of plant origin II. Fresh and dried fruits
Abstract
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.
... Finally, it is important to know the main contributors of luteolin derivates in vegetal food. After a comprehensive data comparison [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], it was found that peppermint, celery, Mexican oregano, tansy leaf, fenugreek seeds, rosemary, sage, and rooibos are the richest sources of luteolin derivatives in human food. Also, it was found that luteolin-O-glycosides are more prevalent than luteolin-C-glycoside. ...
... According to the available data reports [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], the most abundant sources of luteolin-7-O-glucoside are Mexican oregano (297.67 mg/100 g dried herb), celery (80 mg/100 g raw seed and 1.17 mg/100 g fresh leaves), black olives (14.50 mg/100 g raw fruits), peppermint (10.90 mg/100 g dried herb), and lentils (0.12 mg/100 g raw beans). ...
... In the case of luteolin-8-C-glucoside, quantitative data are scarce; according to the data reported [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], the richest sources of luteolin-C-glycosides are the rooibos tea (172-591 mg/dry weight) followed by the green tea (2.5-21.9 mg/dry weight), oolong tea (14.8 mg/dry weight), and black tea (5.9-14 mg/dry weight). ...
Luteolin derivates are plant compounds with multiple benefits for human health. Stability to heat and acid hydrolysis and high resistance to (auto)oxidation are other arguments for the laden interest in luteolin derivates today. The present study was designed to compare the in silico and in vitro anti-proliferative potential of two luteolin derivates, luteolin-7-O-glucoside/cynaroside (7-Lut) and luteolin-8-C-glucoside/orientin (8-Lut). In silico investigations were carried out on the molecular target, namely, the human dual specificity tyrosine phosphorylation-regulated kinase 2 (DYRK2) in association with its natural ligand, curcumin (PDB ID: 5ZTN), by CLC Drug Discovery Workbench v. 1.5.1. software and Molegro Virtual Docker (MVD) v. MVD 2019.7.0. software. In vitro studies were performed on two human tumor cell lines, glioblastoma (U87) and colon carcinoma (Caco-2), respectively. Altogether, docking studies have revealed 7-Lut and 8-Lut as effective inhibitors of DYRK2, even stronger than the native ligand curcumin; in vitro studies indicated the ability of both luteolin glucosides to inhibit the viability of both human tumor cell lines, up to 85% at 50 and 100 µg/mL, respectively; the most augmented cytotoxic and anti-proliferative effects were obtained for U87 exposed to 7-Lut (IC50 = 26.34 µg/mL). The results support further studies on cynaroside and orientin to create drug formulas targeting glioblastoma and colon carcinoma in humans.
... Juniperus communis (olgunlaşmış) 690,5 (Innocenti vd., 2007) Juniperus communis (olgunlaşmamış) 514 (Innocenti vd., 2007) Thymus vulgaris 452 (Justesen & Knuthsen, 2001), (Wojdyło, Oszmiański, & Czemerys, 2007 (Innocenti vd., 2005) Cynara scolymus 23 (Lattanzio & van Sumere, 1987), (Schütz vd., 2004), (Wang vd., 2003) Cichorium intybus 20,8 (Arabbi, Genovese, & Lajolo, 2004), (Michael vd., 1992), (Innocenti vd., 2005) Rosmarinus officinalis 20 (Justesen & Knuthsen, 2001), (Wojdyło vd., 2007) Citrus limon 19 (Lugasi & Hóvári, 2002), ( 13 (Lugasi & Hóvári, 2000) Petroselinum crispum 10,9 (Arai vd., 2000), (Justesen & Knuthsen, 2001), (Justesen, Knuthsen, & Leth, 1998 (Franke vd., 2004), (Harnly vd., 2006) Cucumis melo 6,4 (Harnly vd., 2006), (Lugasi & Hóvári, 2002), (Sampson vd., 2002) Citrus paradisi 6 (Harnly vd., 2006), (Franke vd., 2004) Tordylium apulum 6 (Trichopoulou vd., 2000) ...
... Citrullus lanatus 4,6 (Arai vd., 2000), (Harnly vd., 2006), (Lugasi & Hóvári, 2002), (Sampson vd., 2002) Beta vulgaris 3,7 (Hertog vd., 1992), (Lugasi & Hóvári, 2000) Nelumbo nucifera 3,6 (Arai vd., 2000) ...
... Brassica oleracea 3, 3 Hertog vd., 1992), (Pellegrini vd., 2010), (Lugasi & Hóvári, 2000) Citrus sinensis 1,9 (Arai vd., 2000), (Franke vd., 2004), (Lugasi & Hóvári, 2002) Allium schoenoprasum 1,5 (Justesen & Knuthsen, 2001), (Trichopoulou vd., 2000) Phaseolus vulgaris 1,3 (Arai vd., 2000), (Franke vd., 2004), (Hertog vd., 1992) Daucus carota 1,1 (Arai vd., 2000), (Bahorun vd., 2004), (Hertog vd., 1992), (Lugasi & Hóvári, 2000) lpomoea batatas 1,1 (Andarwulan vd., 2010), (Franke vd., 2004) Brassicaoleracea var. viridis 0,8 (Young vd., 2005) SONUÇ Luteolin, yapılan pek çok çalışmada antienflamatuar, antimikrobiyal, antikanser, nöroprotektif özellikleri kanıtlanmış olan bir moleküldür. ...
SARS-Cov-2 tüm dünyayı etkisi altına alan ve inhibisyonuna yönelik henüz kesin bir tedavi yöntemi geliştirilememiş bir virüstür. Mevcut tedavi protokolleri yeterli çözüm ortaya koyamamıştır. Virüs inhibisyonuna yönelik yapılan moleküler docking çalışmalarında doğal ürünler arasında Luteolin molekülü öne çıkmaktadır. Luteolin molekülü, Origanum vulgare, Apium graveolens, Thymus vulgaris başta olmak üzere birçok bitkide doğal olarak bulunan bir moleküldür. Luteolin, İran, Brezilya ve geleneksel Çin Tıbbında enflamasyon ile birlikte devam eden hastalıkların tedavisinde uzun süredir kullanılagelmiştir. Antioksidan, antimikrobial, antienflamatuar, kemopreventif, kemoterapötik, kardioprotektif, antidiabetik, nöroprotektif ve antialerjik özelliklere sahip, termostabil bir moleküldür. Luteolin molekülü SARS-Cov-2’nin hücre içine girerken kullandığı furin bağlanma bölgesine bağlanarak, virüsün hücre içine girmesini engelleyebilir. Mevcut kullanım alanları, etki mekanizmaları, SARS-CoV-2 patofizyolojisi ve moleküler docking çalışmaları birlikte değerlendirildiğinde, Covid-19 ile mücadelede Luteolin molekülü umut verici bir terapötik ajan olarak öne çıkmaktadır.
... Plants are rich in diverse class of primary and secondary metabolites (Gupta and Gupta, 2016), mainly II. Phenolics Bhagwat et al. (2014), Harnly et al. (2006), Lugasi and Takács (2002), and Sakakibara et al. (2003) Amaranthaceae Spinacia oleracea Apigenin, luteolin Arai et al. (2000), Bhagwat et al. (2014), Chu et al. (2000), Franke et al. (2004), Hertog et al. (1992a), and Lugast and Hovari (2000) Apiaceae Petroselinum crispum Apigenin/apigenin O-glycosides Luteolin Bhagwat et al. (2014) and Lechtenberg et al. (2007) Petroselinum crispum Apigenin, luteolin Arai et al. (2000), Bhagwat et al. (2014), Justesen et al. (1998), Lugast and Hovari (2000), Mattila et al. (2000), and Sakakibara et al. (2003) Apium graveolens var. dulce, A. graveolens var. ...
... Apigenin O-glycosides Svehlikova and Repcak (2006) Tanacetum vulgare Apigenin, Luteolin Wojdyło et al. (2007) Lactuca sativa Apigenin, Luteolin Arabbi et al. (2004), Arai et al. (2000), Bahorun et al. (2004), Bhagwat et al. (2014), Chu et al. (2000), DuPont et al. (2000), Franke et al. (2004), Harnly et al. (2006), Hertog et al. (1992a), Huber et al. (2009), Lugast and Hovari (2000), and Young et al. (2005) Cynara scolymus Apigenin/apigenin, glycosides Luteolin/luteolin, glycosides Azzini et al. (2007), Bhagwat et al. (2014), Ferracane et al. (2008), Lattanzio and van Sumere (1987), Sch€ utz et al. Chu et al. (2000), Franke et al. (2004), Hertog et al. (1992a), Lugast and Hovari (2000), Miean and Mohamed (2001), Sakakibara et al. (2003), and Young et al. (2005) Cucurbitaceae Citrullus lanatus Luteolin Arai et al. (2000), Bhagwat et al. (2014), Harnly et al. (2006), Lugasi and Takács (2002), Owen et al. (2003), and Sampson et al. (2002) Cucumis melo Luteolin Bhagwat et al. (2014), Harnly et al. (2006), and Lugasi and Takács (2002) Cucirbota sp. Luteolin Bhagwat et al. (2014), Lugasi and Takács (2002), and Miean and Mohamed (2001) Continued Lophatherum gracileBrongn. ...
... Apigenin O-glycosides Svehlikova and Repcak (2006) Tanacetum vulgare Apigenin, Luteolin Wojdyło et al. (2007) Lactuca sativa Apigenin, Luteolin Arabbi et al. (2004), Arai et al. (2000), Bahorun et al. (2004), Bhagwat et al. (2014), Chu et al. (2000), DuPont et al. (2000), Franke et al. (2004), Harnly et al. (2006), Hertog et al. (1992a), Huber et al. (2009), Lugast and Hovari (2000), and Young et al. (2005) Cynara scolymus Apigenin/apigenin, glycosides Luteolin/luteolin, glycosides Azzini et al. (2007), Bhagwat et al. (2014), Ferracane et al. (2008), Lattanzio and van Sumere (1987), Sch€ utz et al. Chu et al. (2000), Franke et al. (2004), Hertog et al. (1992a), Lugast and Hovari (2000), Miean and Mohamed (2001), Sakakibara et al. (2003), and Young et al. (2005) Cucurbitaceae Citrullus lanatus Luteolin Arai et al. (2000), Bhagwat et al. (2014), Harnly et al. (2006), Lugasi and Takács (2002), Owen et al. (2003), and Sampson et al. (2002) Cucumis melo Luteolin Bhagwat et al. (2014), Harnly et al. (2006), and Lugasi and Takács (2002) Cucirbota sp. Luteolin Bhagwat et al. (2014), Lugasi and Takács (2002), and Miean and Mohamed (2001) Continued Lophatherum gracileBrongn. ...
... Olea europea extract is obtained from olive leaves and does not include any allergenic protein typical of olive pollen. The anti-allergic and anti-inflammatory properties of each of the extracts present in the mixture are reported in the literature17181920212223. The beneficial effect of Pantescal in allergic subjects could be ascribed to a synergistic action of the four plant extracts present in this nutraceutical. ...
... They also inhibited nitric oxide and prostaglandin E 2 production in lipopolysaccharide (LPS)-stimulated murine macrophages, suggesting an anti-inflammatory activity of ginseno- sides [20]. Anti-allergic activity of R. nigrum are not supported by a large amount of literature, however this plant is commonly used in folk medicine for the control of allergic symptoms [19]. Recently, a polysaccharide derived from R. nigrum has been demonstrated to alleviate nasal–ocular symptoms, so it appears as a useful food supplement in assisting the treatment of Japanese cedar pollinosis. ...
... Ginseng extracts have been shown to exhibit anti-allergic effects originating from a potent cell membrane-stabilizing activity [20,45]. Blackcurrant (R. nigrum L.) is used for the control of allergic symptoms [19,21]. Data obtained in this study, along with the known properties of each extract contained in Pantescal, allow us to suggest that stabilization of basophil/mast cell membrane could be a possible mechanism underlying the action of Pantescal, leading to a lower responsiveness of cells involved in allergic processes towards aeroallergens. ...
Allergic diseases represent conditions affecting millions of individuals across the world. The objective of this study was to investigate the potential anti-allergic effects of a new nutraceutical ingredient, Pantescal (Bionap, Italy), contained in different food supplements. Pantescal is a mixture of plant extracts, such as Capparis spinosa, Olea europaea, Panax Ginseng and Ribes nigrum. The study was a randomized, double-blind, placebo controlled design. 60 patients allergic to common aeroallergens were chosen. Allergic patients were divided into two groups: one group was supplemented by Pantescal and the other, using a placebo formulation. Two in vitro tests were performed on blood samples taken from patients before and at 2 h, 2, 3 and 10 days after supplementation: cellular antigen stimulation test (CAST) was used to analyze the amount of sulphidoleukotrienes (SLT) production and flow-cytometric antigen stimulation test (FAST) to measure expression of basophil degranulation marker (CD63) was also performed. CAST showed that after 2 and 3 days, a slight decrease of SLT production was evident but only after 10 days did it become significant with a percentage of inhibition (P.I)=43.3%. FAST revealed that there were no statistical differences for the first 2 days after supplementation although there was an inhibitory trend in the supplemented patients. CD63 expression was significantly reduced after 10 days (P.I.=64.8%). This study suggests that Pantescal is effective in reducing allergic biomarkers such as CD63 protein and SLT in atopic subjects. The higher inhibitory effect on CD63 expression compared to SLT production allows us to hypothesize cell membrane stabilization as the main potential mechanism to explain the observed Pantescal protective effects.
... [ [48][49][50][51][52] Content courtesy of Springer Nature, terms of use apply. Rights reserved. ...
... [ [48][49][50][51][52] Caffeic acid It has antioxidant, anti-inflammatory and anticarcinogenic activity. ...
Purpose of the Review
Pomegranate is one of the super fruit and a storehouse of several antioxidants and health-promoting compounds which can act as a natural food additive. The pomegranate processing industry generates huge quantities of by-products, particularly peels (50% of fresh fruit weight), that cause environmental pollution due to improper disposal. In this perspective, the present review article focuses on the chemical composition of pomegranate peel and its application as a natural food additive in different food products such as bakery, dairy, meat/meat products, fish/fish products, edible oils, and packaging materials.
Recent Findings
There is a continuous demand for processed foods exhibiting natural food additives over foods containing synthetic additives/colorants, which can cause serious health implications such as cancer with regular consumption. The food industry is looking for an alternative to synthetic/artificial food additives. To overcome these problems, pomegranate peel or its extract can be used as a natural biopreservative in food products that are prone to fat oxidation and microbial growth.
Summary
Pomegranate peel contains bioactive compounds, especially tannins, phenolic acids, and flavonoids, which have nutraceutical value and possess higher antioxidant activity and antimicrobial properties. Due to these properties, pomegranate peel prevents lipid oxidation in fatty foods and can also retard the microbial growth.
... mg/100 g (Justesen, Knuthsen, & Leth, 1998;Häkkinen et al., 1999Häkkinen et al., , 2000, 0.00-11.90 (Häkkinen et al., 1999;Lugasi & Hovari, 2002;Kállay et al., 2008;Kirakosyan, Seymour, Urcuyo Llanes, Kaufman, & Bolling, 2009), 0.00-4.57 (Häkkinen et al., 2000; and 0.18-0.90 ...
... (Häkkinen et al., 1999(Häkkinen et al., , 2000, 0.00-3.13 (Häkkinen et al., 1999;Lugasi & Hovari, 2002;Kállay et al., 2008), 0.00-0.86 (Häkkinen et al., 2000;Bastos et al., 2015) and 0.70-1.59 ...
... Ribes species contain many active components such as flavonoids [9][10][11], tannins [12], biphenyls [13], anthocyanins and nitrilecontaining compounds [9], polyunsaturated fatty acids [14] and aromatic compounds (including terpenes, esters and alcohols) [15]. ...
... However, volatile oil was detected in leaves of all species only. These results are agreed with the references [9][10][11][12]14]. ...
There are most studies on the antioxidant activity of Ribes nigrum and R. rubrum; however, this activity has been restricted on the other species. In the present study, the phenolic contents and antioxidant activities of different extracts prepared with methanol (MeOH), dichloromethane (DCM), ethyl acetate (EtOAc), n-buthanol (BuOH) and water from the leaf and branch of Ribes alpinum, R. anatolica, R. biebersteinii, R. multiflorum, R. nigrum, R.orientale, R.rubrum and R. uva-crispa, (Grossulariaceae) of Turkish origin were investigated by using in vitro methods.
... Highest concentrations are found in carrot, cabbage, artichoke, tea, celery and apple 211 . The compound is also present in melons, kiwi, lemons, mango, strawberries, pineapple, garlic, pea, soybean or eggplant and many other plants [212][213][214] . Luteolin exhibits various biological activities such as antioxidant, anti-inflammation, anti-allergy, and anticancer effects 215 . ...
Erwinia amylovora is one of the major pathogens of apple. In order to prevent infections by this bacterium, various chemical products are commonly used in industrial agriculture. This, however, poses a heavy burden on the environment, so alternative methods of crop protection are being widely explored. In this regard, the induced formation of natural defense compounds (including phytoalexins) represents a promising alternative to conventional methods of plant protection. Phytoalexins are small antimicrobial secondary metabolites, synthesized "de novo" inplants in response to an infection or abiotic stress. The present work evaluates the impact of Bion® 50 WG, a plant resistance inducer (PRI) on the metabolomic profile of apple seedlings infected with E. amylovora. The chemical profile of samples were studied by two different methods : Laser desorptionionization mass spectrometry (LDI-MS) and liquid chromatography coupled to masss pectrometry, using electro spray ionization (LC-ESI-MS). While both methods revealed different chemical profiles, identical group separation by statistical analysis was observed for all analyzed samples. Moreover, marker signals, responsible for the statistical separation of differently treated plant groups, were identified. Based on database research, high-resolution (HR) MS as well as MS fragmentation patterns, specific immune markers responsible for acquired resistance against E. amylovora are proposed.
... Some of these plant-related compounds, namely flavonoids, have valuable health-promoting effects as antioxidants, anticarcinogens, antivirals, antimicrobials, anthelminthics, and antihormonals (De Beer et al., 2002). Flavonoid phenols and catechin compounds help with lipid oxidization, have a beneficial effect on the digestive system, and can destroy bacteria in mouth, thus stopping plaque on teeth (Lugasi & Hóvári, 2002). Red wines have a higher quantity of antioxidants than white ones as the result of their phenolic content (Landrault et al., 2001). ...
Skin-contact fermented white wines, the so-called orange or qvevri wines, have been gaining international attention from winemakers, importers, sommeliers, consumers, and journalists over the last 10 years. Sommeliers are now regularly pairing orange wines with fine cuisine. This new culinary trend is part of a general move by the consumer wishing to respect the existence of traditions and innovation, combined with a growing interest in environmental awareness and healthy options. Orange wines are made from white grapes using ancient Georgian techniques. The essence of this method is the long skin-contact fermentation in amphorae without any chemicals or specific yeast. In our work, the polyphenol content of orange wines, in particular total polyphenol and catechin content, as well as colour intensity were measured to ensure safe winemaking technology without oxidized components.
... Most previous investigations of flavonoid or phenolic content of watermelon have been limited to determination by colorimetric methods (Asyaz et al., 2010;Chopra et al., 1974;Ibrahim et al., 2010;Tlili et al., 2011;Venkataramaiah and Narayana, 1983). Others have used acid hydrolysis before analysis to measure individual aglycone flavonoids (Harsh and Nag, 1988;Lugasi and Hovari, 2002;Meena and Patni, 2008) or phenolic acids (Das et al., 1967;Venkataramaiah and Narayana, 1983). Delazar et al. (2006) determined a number of flavonone-C-glycosides in Citrullus colocynths fruits. ...
Whiteflies [Bemisia tabaci (Gennadius)] and aphids [Aphis gossypii Glover and Myzus persicae (Sulzer)] are serious threats to watermelon by direct feeding and by transmitting viruses of important virus diseases. The desert watermelon Citrullus colocynthis (L.) has been shown to exhibit resistance to these insect pests and could be a useful source for breeding resistance into watermelon [Citrullus lanatus var. lanatus (Thunbs) Matsum & Nakai]. Using high-performance liquid chromatography (HPLC), we found differences among the chemical profiles of two U.S. PIs of C. colocynthis, one PI of C. lanatus var. citroides, and two heirloom watermelon (C. lanatus var. lanatus) cultivars ('Charleston Gray' and 'Mickey Lee'). Flavonoid and caffeic acid derivatives were identified in the leaf extracts by a combination of ultraviolet (UV) and mass spectrometry (MS) spectral analyses. Four phenolic derivatives of caffeic and/or ferulic acid were found to be essentially unique to C. colocynthis. Total flavonoid content was found to be approximately four to 18 times higher in C. colocynthis accessions and seven to nine times higher in C. lanatus var. citroides as compared with watermelon cultivars. Caffeoylglucose was also identified in the leaves of watermelon cultivars for the first time. Leaf sugar concentrations (198 to 211 mg·dL-1), read from a glucometer, were statistically the same among the various germplasm entries. These results will help in the development of pest-resistant watermelon.
... Olive Hungary China Turkey [196][197][198] Rosmarinic acids [233] secretion and reduction of blood glucose levels [121]. Srinivasan et al. (2012) [122] stated that diosmin (a flavonoid), which can be isolated from various plant sources and citrus fruits, lowers plasma glucose, and increases plasma insulin levels in diabetic rats by ameliorating streptozotocin-and nicotinamide-induced oxidative stress. ...
Diabetes mellitus (DM) is one of the most common endocrine metabolic disorders. In addition to exercise and diet, oral anti-diabetic drugs have been used as a part of the management strategy worldwide. Unfortunately, none of the conventional anti-diabetic drugs are without side effects, and these drugs pose an economic burden. Therefore, the investigation of novel anti-diabetic regimens is a major challenge for researchers, in which nature has been the primary resource for the discovery of potential therapeutics. Many plants have been shown to act as anti-diabetic agents, in which the main active constituents are believed to be polyphenols. Natural products containing high polyphenol levels can control carbohydrate metabolism by various mechanisms, such as protecting and restoring beta-cell integrity, enhancing insulin releasing activity, and increasing cellular glucose uptake. Blackberries, red grapes, apricots, eggplant and popular drinks such as coffee, cocoa and green tea are all rich in polyphenols, which may dampen insulin resistance and be natural alternatives in the treatment of diabetes. Therefore, the aim of this review is to report on the available anti-diabetic polyphenols (medicinal plants, fruits and vegetables), their mechanisms in the various pathways of DM and their correlations with DM. Additionally, this review emphasizes the types of polyphenols that could be potential future resources in the treatment of DM via either novel regimens or as supplementary agents.
... Many of the current researches in food technology are focused on the tuning up of novel thermal treatments able to preserve in the final products their original characteristics, especially nutritional values and flavours (Lugasi & Takács 2002;Barba et al. 2008), together with the use of microencapsulated additives (Barba et al. 2009a;Dalmoro et al. 2010). To this aim, unit operations on food (thawing, drying, blanching, freeze-drying, sterilisation, baking, etc.) are addressed to minimise the adverse effects of processing and, responding to the new approaches of the process intensification, to reduce the treatment costs (resources and energy requirements) (Ku et al. 2002;Marra et al. 2007;Romano & Marra 2008; Barba & d'Amore 2012;Dalmoro et al. 2012a,b;Fekete et al. 2012). ...
The effects of microwave assisted drying on banana fruit was evaluated. Water, reducing sugars, and polyphenol contents, as well as poly-phenol-oxidase activity were evaluated along the radial and axial positions in thick slices of banana, according to a properly defined cutting and assaying protocol. The effects of the microwave-assisted drying process were compared to the convective air-assisted drying resulting faster than the conventional process. In particular, the resulting samples were homogeneous in the water content; the contents of reducing sugars were strongly decreased on drying with microwaves; the poly-phenol-oxidase was inactivated by the high temperature produced by the process and thus the polyphenols content remained practically the same as in the fresh product.
... Sour cherry (Prunus cerasus L.) is one of the most appreciated fruit in Hungary due to its attractive aroma, unique taste and richness in phenolic compounds, which are important to the human diet (LUGASI & HÓVÁRI, 2002;BUŠIC et al., 2008;STÉGER-MÁTÉ et al., 2010;CSERJÉSI et al., 2011). Thus, gentle preservation of its original benefi ts is essential. ...
Different osmotic agents (OA), such as potassium acetate (CH3COOK), potassium carbonate (K2CO3) and ammonium nitrate (NH4NO3), have been examined as alternatives to the traditionally used calcium chloride (CaCl2) for osmotic distillation concentrating of clarified and pre-concentrated sour cherry (Prunus cerasus L.) juice. Comparison of the process performances based on the permeate fluxes has been carried out. Regarding the permeate flux results, simplified estimation of the overall mass transfer coefficient of the most effective osmotic agent and the reference (CaCl2) solution has been also performed. Furthermore, analytical methods such as total antioxidant activity (TAA) and total polyphenolic content (TPC) using spectrophotometric assays have been also carried out to evaluate the effect of the osmotic distillation on the valuable compounds content of concentrated sour cherry juice. CH3COOK was found to be the most effective, resulted more than 25% higher permeate flux during the sour cherry juice concentration. K2CO3 and NH4NO3 were less effective. The simplified mass transfer estimation showed that the CH3COOK is more effective only at near saturated concentrations compared to the CaCl2. Regarding the TAA and TPC contents, a significant loss was found in case of all OAs during the concentration procedures.
... The content of flavonoids ranged from 3.06 to 4.01 g/kg FM (Table 2 ). Nevertheless, in fruit lower values are mostly presented (Lugasi, Hovari 2002; Wolfe, Liu 2003). Flavonoids are known to retain free radical scavenging activity by forming complexes with metal ions. ...
2011. Antioxidant and radical oxygen species scavenging activities of 12 cultivars of blue honeysuckle fruit. Hort. Sci. (Prague), 38: 63–70. The fruit of blue honeysuckle (Lonicera caerulea L. var. kamtchatica (Sevast.) Pojark.) belongs to the fruit of great value because of itsunique chemical composition. The aim of our measurement of this fruit species was to select the cultivars which could be the most suitable food supplement in relation to strengthening human immunity system. The comparison of the fruit of 12 cultivars was made. The highest contents of polyphenolic substances were recorded in the cultivar Zolushka with the value of 9.03 g of gallic acid/kg fresh mass. In particular cultivars the DPPH (2,2-diphenyl-1-picrylhydrazyl) test was performed to determine antioxidant activity which ranged from 6.59–10.17 g of ascorbic acid equivalent/kg fresh mass. For comparison, scavenging activity of reactive oxygen species (superoxide anion, hydroxyl radical, and nitric oxide) was determined by using a 25% methanolic extract of fruit of particular cultivars. Antioxidant potential was also assessed using the rat liver slice model. The highest values of scavenging activity were found in the cultivars Zolushka, Goluboe vreteno, and Gerda. The cultivars Zolushka, Goluboe vreteno, and Gerda had also high values of flavonoids. The presented results may be used when popularizing this fruit species and also when studying the properties of new food and genetic resources.
... Vol. 76, Nr. 7, 2011 r Journal of Food Science C993 others 2007; Jacques and others 2009). In general, these small fruits also present a large variation in their flavonoid contents, ranging from 14 to 290 mg/100 g (Lugasi and Hóvári 2002;Lin and Tang 2007). When our results are compared with these values, it seems that the obtained polyphenol and flavonoid con- tents are in good agreement with published values for other small fruits. ...
Strawberry guava (Psidium cattleianum Sabine) is a native fruit of Brazil widely consumed fresh and used in the food industry. In this context, the present study deals with the chemical characterization and the antioxidant activity of the red (Psidium cattleianum) and yellow (P. cattleianum var. lucidum Hort.) strawberry guava fruits, cultivars Irapuã and Ya-Cy, respectively. Knowledge of chemical composition is fundamental to human nutrition, contributing to the quality of foods. Phenolic compounds in both fruits were analyzed by HPLC–DAD and the total flavonoid content was determined by the Folin–Ciocalteu assay. The antioxidant activity was evaluated by the total reactive antioxidant (TRAP) method. Psidium cattleianum presented a higher content of polyphenolic compounds than P. cattleianum var. lucidum (501.33 and 292.03 mg/100 g, respectively), with hyperoside being one of the major flavonoids identified for both cultivars. In addition to flavonoids, P. cattleianum presented an anthocyanin, identified as cyanidin. The antioxidant activity varied in a concentration-dependent manner for both strawberry guava species. The volatile oils in fruits and fatty acids in seeds were quantified by GC-EM. The analysis of the essential oil of yellow strawberry guava was compared with a previous study on the red cultivar, revealing β-caryophyllene as the main component in both oils. The fatty acid composition was also quite similar and was especially characterized by the presence of unsaturated fatty acids (86.25% and 76%, respectively), among which linoleic acid as the most abundant.
Practical Application: In this study, the chemical characterization and the antioxidant activity of the red (Psidium cattleianum) and yellow (P. cattleianum var. lucidum Hort.) strawberry guava fruits were investigated. This is important for potential application of strawberry guava as functional food. Moreover, it may be the experimental basis for further development and use in food industry.
... The content of flavonoids ranged from 3.14 to 4.89 g/kg FM (Table 2). In other fruit lower values are common [20]. Considering the fact that all cultivars were grown under identical conditions and in the same locality, it is possible to conclude that one can clearly see cultivar variability, which is quite typical of fruit [21]. ...
In the literature there is little available information concerning European cranberrybush fruit (Viburnum opulus var. edule). This plant can be cultivated, even in harsh climatic conditions, because of its low environmental demands, and it is possible to harvest the fruit even in the snow cover. The aim of this study was to determine the content of polyphenolics, antioxidant activity, flavonoids and vitamin C in the fruit of three cultivars Leningradskaya otbornaya , Souzga and Taezny rubiny of this species. In the case of polyphenolics, high contents [up to 8.29 g of gallic acid/kg of fresh mass (FM)] were observed. The 1,1 -diphenyl-2-picrylhydrazyl (DPPH) and 2,2 -azinobis-3-ethyl-benzthiazino-6-sulphonic acid (ABTS) tests were applied to determine antioxidant activity, which was also high in comparison with other fruit species. The corresponding correlations between the polyphenolic content and antioxidant activity were in case of the DPPH test r(2) = 0.88 and for the ABTS test r(2) = 0.98. For comparison, the scavenging activity towards reactive oxygen species (superoxide anion, hydroxyl radical and nitric oxide) was determined by using a 25% fruit extract of particular cultivars. Antioxidant efficiency was also assessed using the rat liver slice model. Furthermore, the contents of flavonoids and vitamin C were assayed, giving values of 4.89 g/kg and 1.64 g/kg FM, respectively. The work should contribute to the popularization of this species as a promising crop plant in human nutrition.
... Allo stato attuale, non siamo a conoscenza di altri lavori in letteratura sul destino dei polifenoli dopo l'essiccamento dei fichi freschi, e tantomeno sui cambiamenti che si manifestano durante la conservazione. Infatti, gli studi presenti in letteratura sull'argomento hanno focalizzato l'attenzione o sui fichi freschi (Siewek et al., 1985; Solomon et al., 2006) o sui fichi essiccati (Lugasi e Hóvári, 2002; Vinson, 1999; Vinson et al., 2005). Il frutto del fico, infatti, essendo altamente deperibile, si conserva molto bene quando essiccato. ...
In this paper changes of polyphenols in fresh
figs after hot drying and during storage are
reported. Fig fruits were analyzed before
and after hot air drying, using a tangential
air-flow cabinet and, afterwards, dried fruits
were analyzed at 4, 8, and 12 months of
storage. Polyphenol analysis by HPLC-DAD
permitted to identify four compounds:
two anthocyanins, the flavonol rutin
and the chlorogenic acid. The obtained
results pointed out the role of dehydration
in drastically reducing the polyphenol
compounds. In particular the disappearing
of chlorogenic acid after the dehydration and
of the two anthocyanins during the first four
months of storage has been observed. The
rutin decreases by 60% after dehydration,
but at the end of storage (12 months) is still
present.
Nel lavoro sono riportate le variazioni del
contenuto polifenolico in fichi freschi, dopo
essiccazione e durante la conservazione
per un anno alla temperatura di 20°C. I
fichi sono stati analizzati prima e dopo
l’essiccazione, avvenuta in un essiccatoio a
flusso d’aria tangenziale e, successivamente
i fichi essiccati sono stati analizzati a 4, 8 e
12 mesi di conservazione. L’analisi in HPLC
dei polifenoli ha permesso il riconoscimento
di quattro composti: due antociani, un
flavonolo glicosilato (rutina) e un acido
idrossicinnamico (acido clorogenico).
I risultati mostrano che il processo di
essiccazione riduce drasticamente la quantità
dei composti fenolici. In particolare l’acido
clorogenico scompare completamente dopo
il processo di essiccazione; si ha anche la
scomparsa degli antociani dal quarto mese di
conservazione e la rutina diminuisce del 60%
circa dopo l’essiccazione ma rimane presente
nei 12 mesi di conservazione.
Beta vulgaris L. is an edible plant with health-beneficial activities. The profile of betaxanthins is more complex than previously described in beetroot cultivars. Twenty-four betaxanthins were detected in extracts of the peel and flesh of five cultivars by HPLC-DAD-ESI-MS, of which two new betaxanthins (arginine-Bx and ornithine-Bx) were detected for the first time in B. vulgaris cultivars. The content of betaxanthins in the studied cultivars decreased in the Tytus > Ceryl > Chrobry > Forono > Boldor sequence. The highest content of compounds (1231 mg/100 g DE) was observed in the Tytus cultivar (peel). The peel of B. vulgaris, which is often considered a waste, appeared to be a richer source of betaxanthins compared to its flesh. Antibacterial and antifungal activities were determined against twenty-three microorganisms. Tytus (peel) showed a moderate or good bactericidal effect, especially against the majority of Gram-positive bacteria as well as against most of the tested fungi (MIC = 0.125–0.5 mg/mL) and additionally characterized by low cytotoxicity towards non-cancerous cells (CC50 = 405 μg/mL, CC50—50% cytotoxic concentration). Tytus flesh also showed a high cytotoxicity value against human cervical adenocarcinoma (HeLa), with CC50 of 282 μg/mL. Correlation analysis was used to determine the relationship between the betaxanthin profiles and antimicrobial and anticancer activities. Arginine-Bx, proline-Bx, and tryptophan-Bx were indicated as active against HeLa and the colon cancer cell line (RKO), while asparagine-Bx and phenylalanine-Bx was responsible for activity against all tested bacterial and yeast species. The significant effectiveness and safety of these beetroots make indicated compounds promising applicants as antimicrobial and anticancer agents.
Food is our daily companion, performing numerous beneficial functions for our bodies. Many of them can help to alleviate or prevent ailments and diseases. In this review, an extensive bibliographic search is conducted in various databases to update information on unprocessed foods with anti-inflammatory and antioxidant properties that can aid in treating diseases such as cancer. The current state of knowledge on inflammatory processes involving some interleukins and tumor necrosis factor-alpha (TNF-α) is reviewed. As well as unprocessed foods, which may help reduce inflammation and oxidative stress, both of which are important factors in cancer development. Many studies are still needed to take full advantage of the food products we use daily.
Flavonoids have a broad spectrum of established positive effects on human and animal health. They find an application in medicine for disease therapy and chemoprevention, whence the interest in flavonoids increases. In addition, they are used in food and cosmetic industries as pigments and biopreservatives. Plants are an inexhaustible source of flavonoids. The most important step of plant raw material processing is extraction and isolation of target compounds. The quality of an extract and efficiency of a procedure are influenced by several factors: Plant material and pre-extracting sample preparation, type of solvent, extraction technique, physicochemical conditions, etc. The present overview discusses the common problems and key challenges of the extraction procedures and the different mechanisms for selective extraction of flavonoids from different plant sources. In summary, there is no universal extraction method and each optimized procedure is individual for the respective plants. For an extraction technique to be selective, it must combine an optimal solvent or mixture of solvents with an appropriate technique. Last but not least, its optimization is important for a variety of applications. Moreover, when the selected method needs to be standardized, it must achieve acceptable degree of repeatability and reproducibility.
Today’s programmes aiming at enhancement of fruit and vegetable consumption have been intensified. In the unanimous view of experts, different health problems, such as those of the immune system, inflammations, and even certain cancerous diseases can be prevented and/or cured with regular consumption of fresh (raw) fruit and vegetables. It is well-known fact that among the biologically valuable components, antioxidant compounds – C- and E vitamins, as well as carotinoides – play an important role. In this field, Hungary can expect success in the future since it has excellent plant genetic stock. Regretfully, national data banks regarding cultivation technology, cultivation areas or varieties for fruits and vegetables and their antioxidant contents do not exist in Hungary. Nevertheless, in connection with the so-called “Hungaricums” its existence would be of urgent necessity. Such excellent Hungarian products are – among others – a lot of sour cherry varietiles, the Szeged green pepper and the Makó onion. They enjoy high priority as “Hungaricums” even in the European Union and such activities that support these kinds of products should be enhanced by intense and consequent research work, which may prove their role as functional foods. Presently’ the USA leads in the research of antioxidant compounds of sour cherry, and so far 17 of these compounds have been found partly in Hungarian varieties. Similar research on green, and ‘pritamin’ peppers have not gone so far since they were limited only for seasoning paprika. In Hungary, studies on onion and garlic have not been performed. It should be mentioned that due to the continental climate, these products may be cultivated, consumed or processed only in a limited period. Taking this into consideration, processing and conserving methods are needed which make the consumption of these fruit and vegetables as functional food possible year-round. Scientific establishment of this set of questions is of current concern, because consumption of these products could have an important role in improving the health status of the Hungarian population in the future.
To find new antiviral agents from natural sources, methanol and aqueous extracts of leaves and fruits of Ribes uva-crispa and Ribes multiflorum naturally grown in Turkey were investigated as in vitro to reveal their antiviral activities against Herpes simplex virus type 1. All experiments were performed in 96-well plates and results were measured with XTT-based colorimetric assay. Results demonstrated that all extracts have no cytotoxic effect on vero cells at 10000 µg/mL, while they also exhibited anti-HSV-1 activity with different percentages of protection (varying between 2.65%-50.40%) in 10000 µg/mL which was at the highest concentration in vero cells. 50% effective concentrations (EC 50) of the extracts which were determined having percentage of protection against HSV-1 at concentrations lower than 10000 µg/mL were calculated using GraphPad Prism Version 5.03 statistics program with non-linear regression analysis. These extracts were determined to have EC 50 values ranging between 9710-70600 µg/mL and selectivity index (SI) are ranging between 0.14-1.03. On the basis of these results we believe that it would be worthwhile expanding these studies to include additional species of Turkish plants.
Flavones are a class of flavonoids that are a subject of increasing interest because of their biological activities in vitro and in vivo. This article reviews the major sources of flavones and their concentrations in food and beverages, which vary widely between studies. It also covers the roles of flavones in plants, the influence of growing conditions on their concentrations, and their stability during food processing. The absorption and metabolism of flavones are also reviewed, in particular the intestinal absorption of both O- and C-glycosides. Pharmacokinetic studies in both animals and humans are described, comparing differences between species and the effects of glycosylation on bioavailability. Biological activity in animal models and human dietary intervention studies is also reviewed. A better understanding of flavone sources and bioavailability is needed to understand mechanisms of action and nutritional intervention.
A number of crops defined in culinary terms as vegetables are by botanical definition fruits. In most cases they belong in two families: Solanaceae (tomato, Capsicum spp., eggplant/aubergine) and Cucurbitaceae (pumpkin, squash, gourds, vegetable melons). Vegetable fruits offer great diversity in phytochemical composition; carotenoids are often present but they also contain phenolics and other bioactives. Within this group of fruits tomatoes have the largest body of scientific evidence for health benefits, with a link between tomato/lycopene consumption and prevention of prostate cancer well documented from in vitro to human studies. There is also good evidence for bioactives in tomato having benefits for heart health and growing evidence to support a role in skin, bone and eye health. Capsicum species have received considerable attention, with health effects from anticancer to weight management attributed to capsaicin and capsinoids. The weight of scientific evidence supports the use of vegetable fruits in the development of functional foods.
In this paper changes of polyphenols in fresh figs after hot drying and during storage are reported. Fig fruits were analyzed before and after hot air drying, using a tangential air-flow cabinet and, afterwards, dried fruits were analyzed at 4, 8, and 12 months of storage. Polyphenol analysis by HPLC-DAD permitted to identify four compounds: two anthocyanins, the flavonol rutin and the chlorogenic acid. The obtained results pointed out the role of dehydration in drastically reducing the polyphenol compounds. In particular the disappearing of chlorogenic acid after the dehydration and of the two anthocyanins during the first four months of storage has been observed. The rutin decreases by 60% after dehydration, but at the end of storage (12 months) is still present.
BACKGROUND: This study focused on the contents of flavonoid compounds in vegetables. Generally vegetables have contributed to a healthy diet, arisen from contains a large amount of fiber and functional ingredients. And flavonoid compounds are one of major functional components in the vegetables. currently research of flavonoid contents does not enough, specially in the part of homegrown vegetable. METHODS AND RESULTS: Vegetable samples were purchased in domestic market. Sample extraction by methanol, distilled water, and formic acid based solvent. Also same solvent used for mobile phase in UPLC. Eleven types of flavonoid compounds were analyzed with same kind of external standard and one kind of internal standard (galangin) for quantification. Standard calibration curve presented linearity with the correlation coefficient R^2 > 0.98, analysed from 1 to 50 ppm concentration. The quantitative value and multivariate analysis results were derived from the Excel and SIMCA-P11. Overall, onion has largest amount(916.5 mg/100 g) of flavonoid and also other vegetables have has significant amount[Mugwort: 138.8, Galic stem:123.6 mg/100 g etc.] of flavonoid compounds. Edible portion of vegetables per share for simulating by SIMCA-P11, root vegetables has had difference with other vegetables according to distributions and amounts of flavonoid compounds. CONCLUSION: Optionally, the results from this experiment can use to select the material for flavonoid researches. And based on these results, if this experiment will be continuously complemented, and performed, could used in various fields.
Flavonoids have been hypothesized to reduce the risk of chronic diseases, but the lack of a flavonoid database hampered epidemiological studies addressing this issue in Korea. In this study, we developed a flavonoid database, based on a systematic review. A total of 1549 food items containing flavonoids were selected using the Korean Nutrient Database. Among them, flavonoid contents for only 649 food items were evaluated with analytical values and the remaining 900 items were replaced with adaptations or calculations from similar items. The developed flavonoid database covered 93.2% of fruits and fruit juices, 76.1% of vegetables, 98.4% of legumes and legume products, and 85.0% of all plant foods overall (1,549 items) as reported by the 24-hr dietary recall method regarding the 2008 Korean National Health and Nutrition Examination Survey. We found that this flavonoid database, overall, included 95.6% of all mainly consumed plant foods by Koreans. This flavonoid database is expected to be useful in regards to the correlation study of flavonoid intake and chronic diseases.
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.
Anthocyanin and polyphenolic compounds present in fruits of mulberry (Morus alba L.) were determined and the influence of temperature and UV irradiation on stability of the anthocyanin-copigment complex were investigated. The copigmentation substance selected in non-anthocyanin fraction from mulberry for the study included: phenolic acid (hydroxybenzoic acid) and flavonoid (quercetin-3-O--D-glucopyranoside). The copigmentation effect increased with the copigment content. UV irradiation had a stronger degradation effect on the copigmentation complex than heating at . The non-anthocyanin fraction of mulberry and isolated flavonoid (quercetin-3-O--D-glucopyranoside) from mulberry fruit predominated over other copigment substances.
Of the twenty table beet (Beta vulgaris L. ssp. esculenta convar. crassa provar. conditiva ALEF.) cultivars investigated for several nutritionally important components (betaine, betanin, phenol, glucose, fructose, sucrose) formerly (HÁJOS et al., 2004), cultivar Ditroit having average quality parameters was chosen for in vitro animal experiments. The hyperlipidemic rat model is suitable to study the physiological effect of table beet on the metabolic alterations and the redox homeostasis in the liver. In fatty liver, as a consequence of hyperlipidemy, the redox homeostasis is strongly injured. General biologically active compounds of table beet have indirect lipid lowering effect and antioxidant properties. Therefore, the effect of lyophilised table beet powder was studied on altered lipid metabolism and redox parameters in hyperlipidemic rats. Hyperlipidemy was induced by a fat-rich diet, and both in the control group and in the hyperlipidemic group, animals were treated with the lyophilised table beet powder (2 g bwkg-1) added into rat chow for 10 days parallel with the feeding. Significant antioxidant activity of table beet was recorded in the hyperlipidemic liver. This phenomenon was expected because of the significant amount of betanin and the high total polyphenol content of the beet. Significant beneficial changes were also observed in the serum cholesterol level, alkaline phosphatase and alanine-aminotransferase activities, although a non-expected elevation was observed in the serum bilirubin level in hyperlipidemy. Non-specific H-donor activity was not changed, but protein related free SH-group concentration was decreased in the plasma. Serum triglyceride level was better after table beet treatment in normolipidemy, only. Change of redox-homeostasis was more favourable in the liver during the treatment. Diene conjugate content and the level of induced free radicals decreased during the table beet treatment in case of fatty liver. These changes were due to the bioactive components of the commercially available table beet. Consequently, table beet due to its specific qualities beneficially influences several metabolic pathways, therefore it can be considered as a functional food.
Late blight of potato, caused by Phytophthora infestans was studied by using a resistant clone of potato on one side and a susceptible clone on the other side. A gene coding putatively
for an α-galactosidase has been isolated by mRNA reverse transcription polymerase chain reaction differential display and
was shown to be differentially expressed between the resistant and the susceptible clone. α-Galactosidases catalyse the hydrolysis
of α-1,6 linked α-galactose residues from oligosaccharides and it could be shown in the present work that raffinose content
decreases at 30 h after infection by P. infestans in the resistant clone.
The authors investigated the in vitro antioxidant properties of nine selected flavonoid aglycons, namely quercetin, kaempferol, myricetin, apigenin, luteolin, daidzein, genistein, formononetin and biochanin A. The in vitro antioxidant power of flavonoids basically depends on their chemical structure. The concentration of those flavonoids in vegetables and fruits frequently consumed in Hungary was examined by a RP-HPLC method. Referring to the total flavonoid content, rich sources were onions, parsnip, spinach, different parts of celery, and lentils. Among the fruits berries were very rich sources of flavonoids (blackberry, red current). The flavonoid intake was estimated in two groups, first included more than 500 schoolboys and girls aged 12-15 years, and the second group was about 200 healthy adults aged 25-60 years. The average dietary flavonoid intake of the children and the adults was 19.5±26.6 and 18.8±28.9 mg/day, respectively. The flavonoid intake showed high differences among the subjects. The consumption of flavonoids in the children's group was from 0 to 179 mg/day, and in the adults¢ group from 0.5 to 310 mg/day. Although two groups in our study did not represent exactly the total Hungarian population it is supposed that the average daily flavonoid intake of the population is not different from these data. The estimated Hungarian intake is very similar to that of others published in the literature.
Seventeen Thermomyces lanuginosus strains, cultivated on raffinose and sucrose, were ranked on the basis of -galactosidase activities. T. lanuginosus CBS 395.62/b strain show- ed the highest -galactosidase activity on both investigated carbohydrates. Several carbon sources were tested as potential inducers for the -galactosidase synthesis. On melibiose substrate -galactosidase activity was higher in the intracellular fraction than in the filtrate of the fermentation broth, although both values were very low and did not reach the va- lue of 1 U/mL. Raffinose, sucrose and Lactosucrose ® proved to be inducers for -galacto- sidase production. The highest titer (about 30 U/mL) was achieved on 1 % sucrose and 0.45 % ammonium acetate. The optimum sucrose and ammonium acetate concentrations, at which about 90 U/mL -galactosidase activity was reached during an 8-day fermenta- tion, were 3 and 0.9 %, respectively.
Fruits are rich sources of flavonoid polyphenolic compounds that seem to be associated with favourable health-effects. Commonalities and differences are well known in the flavonoid contents of different fruit crops, which suggest alterations in the flavonoid biosynthesis pathway of fruit tissues. This review aims to collect data from molecular genetic studies on the structural and regulatory genes in grape, berries, citrus, pomes and stone fruits to get impression on the state of the art of this field of science. Results indicate that the expression of flavonoid genes is a genotype-dependent and developmentally regulated process. In addition, genetic alterations resulting in specific changes in flavonoid composition are also highlighted. Analysis of colour mutants of grape, bilberry and orange identified the genes responsible for the altered phenotype, and this strategy might offer valuable tools to identify several other candidate genes in different fruits. The application of such data is also discussed in relation with the development of molecular markers.
The aim of this study was to determine the concentrations of phenolic compounds and their antioxidant activity in different
kinds of juice: clear, cloudy, and puree which were made from three different strawberry cultivars (Elkat, Kent, and Senga
Sengana). The anthocyanins, p-coumaric acid, ellagic acid, quercetin, keampferol derivatives, (+)-catechin, proanthocyanidins content and degree of proanthocyanidin
polymerization, were determined both in the fresh and after 6months of storage at 4 and 30°C. Freshly produced juices contained
higher amounts of phenolics, especially of anthocyanins and proanthocyanidins, than those stored for 6months at 4 and 30°C.
The processing of the clear juice showed the higher loss of all phenolic compounds. The antioxidant capacity was the smallest
for clear, and the highest for the puree juices. This was assessed by measurements made with different antioxidant activity
assays: ABTS and FRAP. The puree of strawberry juice had significantly higher levels of the phenolic compounds and showed
more antioxidant activity than the clear and cloudy juices, before and after storage in all strawberry cultivars.
A GC-MS method - developed for the simultaneous quantitation of mono-, di- and trisaccharides, sugar alcohols and acids, as their trimethylsilyl (oxime) ether/ester derivatives prepared in the presence of the fruit matrix has been extended. The reproducible determination of derivatized sour cherry constituents was performed both on the basis of total ion current (TIC) and selective ion values; ensuring their identification and quantitation over a wide concentration range (1 10–2 to 41%, calculated on dry matter basis of the samples). The GC-MS procedure was utilized to prove the advantage of the direct derivatization process, in the presence of the fruit matrix, and to determine the changes in the sugar/sugar alcohol/carboxylic acid/flavonoid hydrolysis products of three sour cherry cultivars, as a function of their harvesting dates and storage conditions. Reproducibility of quantitations in the case of the main constituents, calculated on the basis of their TIC values provided an average reproducibility of 2.3 and 3.6 RSD%, for components present in concentrations of 1% and 1%, respectively.
An α-galactosidase was isolated from a culture filtrate of Lenzites elegans (Spreng.) ex Pat. MB445947 grown on citric pectin as carbon source. It was purified to electrophoretic homogeneity by ammonium sulfate precipitation, gel filtration chromatography and anion-exchange chromatography. The relative molecular mass of the native purified enzyme was 158 kDa determined by gel filtration and it is a homodimer (Mr subunits = 61 kDa). The optimal temperature for enzyme activity was in the range 60-80 °C. This α-galactosidase showed a high thermostability, retaining 94 % of its activity after preincubation at 60 °C for 2 h. The optimal pH for the enzyme was 4.5 and it was stable from pH 3 to 7.5 when the preincubation took place at 60 °C for 2 h. It was active against several α-galactosides such as p-nitrophenyl-α-D-galactopyranoside, α-D-melibiose, raffinose and stachyose. The α-galactosidase is a glycoprotein with 26 % of structural sugars. Galactose was a non-competitive inhibitor with a Ki = 22 mM versus p-nitrophenyl-α-D-galactoside and 12 mM versus α-D-melibiose as substrates. Glucose was a simple competitive inhibitor with a Ki = 10 mM. Cations such as Hg(2+) and p-chloromercuribenzoate were also inhibitors of this activity, suggesting the presence of -SH groups in the active site of the enzyme. On the basis of the sequence of the N-terminus (SPDTIVLDGTNFALN) the studied α-galactosidase would be a member of glycosyl hydrolase family 36 (GH 36). Given the high optimum temperature and heat stability of L. elegans α-galactosidase, this fungus may become a useful source of α-galactosidase production for multiple applications.
Thermophilic fungus Thermomyces lanuginosus CBS 395.62/b strain is able to grow and synthesise extracellular α-galactosidase in media containing galactomannan such as locust bean gum (LBG) or guar gum (GG). Production of extracellular α-galactosidase was enhanced from 1.2 U/mL to 4–6 U/mL meaning about 3–5 times increase by optimisation of medium composition. This enzyme was purified to homogeneity by partial precipitation with 2-propanol and different liquid chromatographical steps. The developed purification protocol yielded 22% of enzyme activity with 900 purified fold. Molecular mass of the purified α-galactosidase enzyme was estimated to be 53 kDa. Maximal catalytic activity of the enzyme was obtained in the acidic pH range between pH 4.6 and 4.8 and in the temperature range 60–66 °C. More than 95% of enzyme activity was remaining after 1-day incubation at 70 °C and on pH in the range from 4.0 to 7.0. The enzyme activity was significantly stimulated by Mg2+, Mn2+ and K+ ions, while considerably inhibited by the presence of Ca2+, Ag+ and Hg2+.
The stability of phenolic compounds of three strawberry cultivars was evaluated for changes during prefreezing treatments, storage and various freezing and thawing conditions. Polyphenol content was determined by HPLC–DAD–FL. The sum of assayed polyphenolic (proanthocyanidin and monomeric flavan-3-ols, anthocyanins, ellagic acid, p-coumaric acid) represented 2858.4 mg/kg in Kent, 2893.1 mg/kg in Elkat, and 2438.0 mg/kg in Senga Sengana. After freezing, 4.5–33.6% of polyphenols were lost; protective effects of prefreezing treatments were seen on anthocyanidins and proanthocyanidins: ascorbic acid was the most effective pretreatment, allowing retention of 3.9–27.5% of anthocyanins, and almost total recovery (3.9–23.9%) when associated with liquid nitrogen freezing. Pectin and sugar only allowed retention of 3.0–25.1% and 5.5–25.4% of the antocyanins, respectively. Thawing of the strawberries in a microwave oven (instead of 20 h at 20 °C) had a further positive effect on retention of anthocyanins, proanthocyanins, (+)-catechin and ellagic acid.
Several seeds and husks of some plants belonging to leguminosae, Graminae, Compositae and Palmae were evaluated as carbon substrates to produce α-galactosidase (α-Gal) by the thermophilic fungus, Thielavia terrestris NRRL 8126 in solid substrate fermentation. The results showed that Cicer arietinum (chick pea seed) was the best substrate for α-Gal production. The crude enzyme was precipitated by ammonium sulphate (60%) and purified by gel filtration on sephadex G-100 followed by ion exchange chromatography on DEAE-Cellulose. The final purification fold of the enzyme was 30.42. The temperature and pH optima of purified α-Gal from Thielavia terrestris were 70 °C and 6.5, respectively. The enzyme showed high thermal stability at 70 °C and 75 °C and the half-life of the α-Gal at 90 °C was 45 min. Km of the purified enzyme was 1.31 mM. The purified enzyme was inhibited by Ag2+, Hg2+, Zn2+, Ba2+, Mg2+, Mn2+ and Fe2+ at 5 mM and 10 mM. Also, EDTA, sodium arsenate, L-cysteine and iodoacetate inhibited the enzyme activity. On the other hand, Ca2+, Cu2+, K+ and Na+ slightly enhanced the enzyme activity at 5 mM while at 10 mM they caused inhibition. The molecular weight of the α-Gal was estimated to be 82 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This enzyme displays a number of biochemical properties that make it a potentially strong candidate for biotechnological and medicinal applications.
Unlabelled:
Mulberry fruits have different chemical compositions because of cultivar variation. In this study, polyphenol profile and volatile composition of alcoholic beverages produced from different mulberries of Da 10, Hongguo 2 hao, and Hongguo 1 hao were investigated. Statistically significant differences were detected in the chemical composition of the analyzed alcoholic beverage samples. The beverage of Da 10 possessed the highest content of total phenols, total flavonoids, and total anthocyanins, which was determined by spectrophotometry analysis, contrarily Hongguo 1 hao beverage showing the lowest. Phenolic acids and flavonols were analyzed by high performance liquid chromatography analysis. Protocatechuic acid was the main phenolic acid in all analyzed alcoholic beverage samples, and its concentration ranged from 8.20 mg L⁻¹ (Hongguo 1 hao beverage) to 29.98 mg L⁻¹ (Da 10 beverage). High level of flavonols was found in both Da 10 and Hongguo 2 hao beverage samples, whereas Hongguo 1 hao beverage sample was characterized with lower level of flavonols. Furthermore, volatile compounds were analyzed by solid phase microextraction-gas chromatography mass spectrometry analysis. The amount of esters varied widely among the 3 alcoholic beverage samples. The concentration of aliphatic alcohols in Hongguo 2 hao and 1 hao beverage samples was higher than Da 10 sample, whereas Da 10 beverage sample contained more aromatic alcohols than the others. Hongguo 1 beverage sample showed the highest concentration of acetic acid. This study demonstrated that quantitative differences of phenolic compounds and volatile compounds among cultivars were significant, which highly affected the quality of alcoholic beverage from mulberry.
Practical application:
Mulberry fruits had different chemical compositions because of cultivar variation. The analyzed Da 10 cultivar of mulberry appeared to be a good raw material for alcoholic beverage-making because of its high level of total sugar and acidity. This study demonstrated that alcoholic beverages from mulberry contain high amounts of polyphenols. These bioactive compounds may act synergistically to promote health, and reduce risk factors of chronic diseases.
Epidemiological studies have consistently shown that eating more fruits and vegetables can aid in preventing stomach, lung, mouth, esophagus, colon, and rectal cancers and other age-related diseases. The incidence of other chronic diseases, such as coronary heart disease, atherosclerosis, and stroke, may also be reduced through increased fruit and vegetable consumption.
It is well known that fruits contain a considerable amount of non-nutritive compounds, which can help to keep man’s health and prevent chronic diseases. In this context, the fig fruit has been scarcely investigated so far. In particular, to our knowledge, any extensive study has been published on the fig phenolic fraction, which plays a key role in health-promoting action. A study was carried out on two fig cultivars, a black and a white. Fresh fruits were peeled and phenols extracted separately from peel and pulp. The extracts were subjected to HPLC-DAD analysis, by monitoring at four wavelengths, 280, 316, 365 and 520 for catechins, hydroxycinnamic acids, flavonols and anthocyanins, respectively. Results showed that phenols are concentrated almost exclusively in the peel, with black cultivar having the highest content. In particular the peel was rich in flavonols, with amounts from 723 to 1450 mg/kg (fresh basis) for white and black figs, respectively. The peel of black figs showed an appreciable content of anthocyanins, which were the only polyphenolic compounds detected in the pulp. No catechins were found.
An analytical study was carried out on phenols in two fig cultivars ( Ficus carica L.), one black and one green. Fresh fruits were peeled and phenols were extracted separately from the peel and the pulp. The extracts were subjected to HPLC-DAD analysis, by monitoring at four wavelengths, 280, 316, 365 and 520 nm for catechins and benzoic acids, hydroxycinnamic acids, flavonols and anthocyanins, respectively. Results showed that phenols are concentrated almost exclusively in the peel, with the black cultivar having the highest content. In particular, the peel was rich in rutin, with amounts from 527 to 1,071 mg/kg (fresh basis) for green and black figs, respectively. The peel of black figs showed an appreciable content of cyanidin 3- O -rutinoside. The pulp of both green and black cultivars contained only cyanidin 3- O -rutinoside, while the cyanidin 3- O -glucoside was found only in the peel of the black figs. Chlorogenic acid and another cinnamic acid were detected in the peel of both cultivars, while benzoic acids and catechins were not present.
The effects of maturation (green, pink, and ripe) on phenolic composition of strawberry cultivars Camarosa, Dorit, Chandler, and Osmanli and their hybrids were investigated using a high-pressure liquid chromatography (HPLC) method. p-Hydroxybenzoic acid, p-coumaric acid, ellagic acid, cyanidin-3-glucoside, pelargonidin-3-glucoside, kaempferol, quercetin, and myricetin were individually quantified for each stage. The highest amounts of anthocyanins were obtained from ripe fruits whereas ellagic acid was found as the main phenolic in the green fruits. Phenolic concentrations were found statistically different in green and ripe fruits. One hybrid was found to have higher phenolic contents than the other genotypes. The p-hydroxybenzoic and p-coumaric acid levels changed during maturation, but no differences in contents of flavonoids in green and ripe fruit were detected.
Diets high in flavonoids have long been associated with nutritional recommendations, a healthy lifestyle, and the prevention of chronic diseases. However, identification of specific beneficial effects from specific flavo-noids and flavonoid-rich foods has been a challenging area, probably due to a nonessential or conditional role for flavonoids in human nutrition. Nonetheless, recent efforts in the area of high flavonoid–containing foods and cardiovascular disease have begun providing the first demonstrations of specific effects and mechanisms of action in well-controlled studies. The early studies have shown that flavonoids have several anti-atherosclerotic activities including anti-inflammatory, antioxidant, anti-proliferative, antiplatelet, and provessel function activities. Cholesterol-lowering and antihypertensive effects of flavonoids have been studied and appear minimal in humans. The studies also demonstrate several possible mechanisms and pleiotropic effects of flavonoids that may be active in reduction in the risk of cardiovascular disease. Several subclasses of flavonoids may contribute toward the apparent beneficial effects and include fla-vones, flavonols, flavanones, catechins isoflavones, proanthocyanidins, and anthocyanidins. Further studies are necessary for confirmation of the beneficial effects, identification of dose-response relationships, and identification the most bioactive flavonoids.
The ftavonoid pigments, one of the most numerous and widespread groups of natural constituents, are ofimportance and interest to a wide variety ofphysical and biological scientists and work on their chemistry, occurrence, natural distribution and biological function continues unabated. In 1975, a mono graph covering their chemistry and biochemistry was published by Chapman and Hall under our editors hip entitled The Flavonoids. The considerable success of this publication indicated that it filled an important place in the scientific literature with its comprehensive coverage of these fascinating and versatile plant substances. The present volume is intended to update that earlier work and provide a detailed review of progress in the ftavonoid field during the years 1975 to 1980. Although cross references are made to The Flavonoids, this supplement is entirely self-contained and where necessary, tabular da ta from the earlier volume are incJuded and expanded here. The choice oftopics in Recent Advances has been dictated by the developments that have occurred in ftavonoid research since 1975, so that not all subjects covered in The Flavonoids are reviewed again here. A major advance in ftavonoid separation has been the app1ication ofhigh performance liquid chromatography (HPLC) and this is reviewed inter alia in the opening chapter on separation techniques. An equally important development in the spectral analysis of ftavonoids has been the measurement of carbon-13 NMR spectra and this subject is authoritatively discussed in Chapter 2 and is also illustrated with the spectra of 125 representative ftavonoids.
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.
A review is presented of the analytical chemistry of the bioflavonoids in fruits with emphasis on work carried out over the last ten years. The analytical procedures that have been developed for flavonoid compounds, e.g., TLC, GC, HPLC and coupled techniques, are discussed (313 references).
Quantitative estimates of conjugated flavonoid content were obtained by using HPLC to analyze the level of free flavonoids present in acid-hydrolyzed extracts from commercial fruits and vegetables. Cherry tomatoes contained 17−203 μg of quercetin g-1 fresh weight compared to 2.2−11 μg g-1 detected in normal-sized Scottish, Spanish, and Dutch beef tomatoes. The quercetin levels in onions ranged from 185 to 634 μg of quercetin g-1 fresh weight. “Round” lettuce contained 11 μg of quercetin g-1 fresh weight compared to 911 μg g-1 in the outer leaves and 450 mg g-1 in the inner leaves of “Lollo Rosso” lettuce. The conjugated flavonoid content of celery was very variable, ranging from undetectable to 40 μg of luteolin and 191 μg of apigenin g-1 fresh weight. Cooking lowered the quercetin content of both tomatoes and onions with greater reductions being detected following microwaving and boiling than after frying. Keywords: HPLC; quantitative analysis; flavonoids; tomatoes; onions; lettuce; celery; diet
The major constituent of the tannin from the walnut pellicle has been isolated. Analyses of numerous derivatives of the compound, for which the name juglanin is proposed, show that its molecular formula is Q27H22O18 and that it contains eleven hydroxyl groups. Acid and alkaline hydrolyses of juglanin give ellagic acid (I), gallic acid and glucose. The yields of these hydrolysis products and the analytical data indicate that juglanin is a polyphenol formed by the esterification of three hydroxyl groups of glucose with a molecule of gallic acid and a molecule of hexahydroxydiphenic acid (II). It is therefore isomeric with corilagin, but differs in the position of attachment of the galloyl and/or hexahydroxydiphenoyl units to glucose.
This paper reviews the occurrence in foods of flavanones, chalcones and dihydrochalcones. The major dietary sources of flavanones and dihydrochalcones are citrus fruits and apples respectively. These compounds may make a greater contribution to the total daily intake of flavonoids than the more extensively studied flavonols. There are no data for plasma or tissue levels, but both endogenous and gut flora metabolites of both classes of compound are found in urine. For these reasons, these compounds deserve greater attention in epidemiological studies.© 2000 Society of Chemical Industry
In this review the qualitative and quantitative occurrence of flavonols and flavones, particularly in fruit and vegetables, are considered. They occur practically in all plants. Their formation normally depends on light so that they are mainly concentrated in the outer tissues. the concentration of flavonols in free standing leaves exceeds that in other parts of the same plant considerably, except in onions.
Flavonols act as antioxidants and protect the ascorbic acid from auto‐oxidation, for example in fruit juices. On the other hand, flavonols can lead to discolourations. Beneficial effects on the human organism have also been described.
Flavonol and flavone glycosides occur in common vegetables, mainly as the quercetin or kaempferol glycosides and less frequently as the luteolin or apigenin glycosides. Their formation normally depends on light, so they are mainly concentrated in the outer tissues. Their concentration in free-standing leaves is considerably greater than that in any other part of the same plant, with the exception of the onion.Flavonol- und Flavon-glykoside kommen in allen Gemsearten vor, hauptschlich als Quercetin- oder Kmpferol- und weniger hufig als Luteolin- oder Apigenin-glykoside. Da ihre Bildung lichtabhngig ist, sind sie im ueren Gewebe angereichert. Die Konzentration ist in freistehenden Blttern mit Ausnahme der Kchenzwiebel erheblich hher als in anderen Teilen der gleichen Pflanze.
Im Obst sind fast ausschlielich die Flavonole Quereetin, Kmpferol und Isorhamnetin (als Glykoside) enthalten, deren Gesamtgehalt — von Erdbeeren Senga Sengana in der Grenordnung von 1 g/kg abgesehen—gering ist (Spuren bis maximal 100 mg/kg Frischgewicht). Im Kernobst sind die Flavonole in der Schale lokalisiert (bis 400 mg/kg). —Hauptflavonol ist meist das Quercetin. Kmpferol kommt vor allem in Erdbeeren und Quitten schalen, Isorhamuetin in Birnenschalen und Myricetin hauptschlich in schwarzen Johannisbeeren vor.Fruits contain almost exclusively the flavonols quercetin, kaempferol and isorhamnetin (as glycosides) in concentrations of traces to maxim. 100 mg/kg fresh weight; only strawberrries Senga Sengana contain about 1 g/kg. In pomefruits the flavonols are localized in the peel in concentrations up to 400 mg/kg. — Main flavonol is mostly quercetin, in strawberries and in quince peels kaempferol, in pear peels isorhamnetin. Only black currants mainly countain myricetin.
This study was undertaken to determine the amount of ellagic acid, a naturally occurring inhibitor of carcinogenesis, in various fruits and nuts. Ellagic acid was extracted from freeze-dried berries, pears, peaches, plums, grapes, apples, kiwi, and several nuts using either acetone/water or methanol. The extracts were treated with trifluoroacetic acid to hydrolyze the ellagic acid glucosides, and analyzed by high-performance liquid chromatography (HPLC). Both acetone/water and continuous soxhlet extraction with methanol were equally effective in extracting ellagic acid from strawberries. In raspberries, the amount of ellagic acid liberated by the two extraction methods was not significantly different after hydrolysis with trifluoroacetic acid. The extracts were stable over 90 days at −20, 4, and 25°C. Analysis showed that every food sample tested contained ellagic acid, but only the amounts present in strawberries (630 μg), raspberries (1500 μg), blackberries (1500 μg), walnuts (590 μg), pecans (330 μg), and cranberries (120 μg ellagic acid/g dry wt) were within the calibration range of the assay. In strawberries, 95.7% of the ellagic acid was found in the pulp while 4.3% was contained in the seeds. The seeds of raspberries contained 87.8% of the ellagic acid, and 12.2% was present in the pulp. The juice of both fruits contained negligible amounts of ellagic acid.
4-oxo-flavonoids are dietary compounds widely distributed in the plant kingdom. Interest in these substances has arisen because of possible effects on human health. Indeed, in spite of extensive metabolism by the intestinal flora, 4-oxo-flavonoids seem to be sufficiently absorbed to have physiological effects. This review discusses the possibilities of a positive role in cardiovascular disease and cancer prevention, particularly by their antioxidant properties and their ability to modulate the activity of many enzymes, and summarizes the data concerning an eventual carcinogenicity of 4-oxo-flavonoids.
Flavonoids are plant phytochemicals that cannot be synthesized by humans. The six classes of flavonoids (flavanones, flavones, flavonols, isoflavonoids, anthocyanins, and flavans) vary in their structural characteristics around the heterocyclic oxygen ring. Flavanones occur predominantly in citrus fruits, flavones in herbs, isoflavonoids in legumes, anthocyanins and catechins in fruits and flavonols in all fruits and vegetables. Food preparation and processing of fresh fruits and vegetables may decrease flavonoid content by 50% owing to leaching into water or removal of portions of the plant that are rich in them. Grains and oils seeds have flavonoids, but processing removes or reduces them. Other plant food groups contain differing amounts of flavonoids. Honey, chocolate, and sweets that contain some plant constituents have flavonoids. Flavonoids are not present in animal foods. Dietary intake estimates vary from 23 mg/day to 1000 mg/day but the number of compounds and classes assessed vary, and all estimates currently are incomplete. In vitro and animal studies have demonstrated that flavonoids have antioxidant and antimutagenic activities. Case control studies suggest that flavonoids may reduce the risk of cardiovascular disease and stroke. Flavonoid classes vary in their absorption and their metabolism is still obscure. They are conjugated in the liver or kidney and excreted into bile or urine. Colonic bacteria split the heterocyclic ring and degrade the flavonoids to phenyl acids which may be absorbed, conjugated, and excreted or metabolized further by colonic bacteria.
A high-performance liquid chromatographic (HPLC) separation method with photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages. The compounds were analysed as aglycones, obtained after acid hydrolysis of freeze-dried food material. Identification was based on retention time, UV and mass spectra by comparison with commercial standards, and the UV peak areas were used for quantitation of the flavonoid contents. Examples of HPLC-MS, analyses of orange pulp, tomato, and apple are presented. The method has been used to screen foods on the Danish market, and the contents of flavones, flavonols, and flavanones were measured.
A rapid method based on RP-HPLC with UV detection is presented for the quantitative determination of five major flavonoid aglycons, viz. quercetin, kaempferol, myricetin, luteolin, and apigenin, in freeze-dried vegetables and fruits, after acid hydrolysis of the parent glycosides. Completeness of hydrolysis and extraction have been optimized by testing systematically different conditions such as acid concentration, reaction period, and methanol concentration in the extraction solution using samples containing various types of flavonoid glycosides. Optimum hydrolysis conditions are presented for flavonol glucuronides, flavonol glucosides, and flavone glycosides. Identity of the flavonoids was confirmed with diode array. Repeatability of the method was good, with coefficients of variation of 2.5-3.1 % for quercetin, 4.6-5.6 % for kaempferol, 4.6 % for myricetin, 3.3 % for luteolin, and 2.8 % for apigenin. CV of the within-laboratory reproducibility was less than 2 times the CV of repeatability. Recoveries of the flavonols quercetin, kaempferol, and myricetin ranged from 77 to 110 %, and recoveries of the flavones apigenin and luteolin ranged from 99 to 106 %. The method presented allows a fast, quantitative, and reproducible determination of five flavonoids in freeze-dried foods.
The content of the potentially anticarcinogenic flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin of commonly consumed beverages was determined by RP-HPLC with UV detection. Flavonoid levels in beer, coffee, chocolate milk, and white wine were below 1 mg/L. Twelve types of tea infusion, six types of wine, apple juice, tomato juice, grape juice, orange juice, grapefruit juice, and lemon juice were analyzed. No luteolin or apigenin were detected in any of the beverages. In red wines and in grape juice quercetin and myricetin levels varying from 4 to 16 mg/L and from 7 to 9 mg/L, respectively, were detected. Quercetin levels in fruit juices were generally below 5 mg/L except for lemon juice (7 mg/L) and tomato juice (13 mg/L). In black tea infusions quercetin (10-25 mg/L), kaempferol (7-17 mg/L), and myricetin (2-5 mg/L) were detected. Flavonoid levels in green tea were comparable to those in black tea. The flavonoid content of tea prepared with tea bags was generally higher than that of tea prepared with loose leaves. Together with data on the flavonoid content of vegetables and fruits published previously (Hertog et al. J. Agric. Food Chem. 1992, 40, 2379-2383), these data provide a base for an epidemiological evaluation of the potentially anticarcinogenic effects of flavonoids.
The content of the potentially anticarcinogenic flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin of 28 vegetables and 9 fruits was determined by RP-HPLC with UV detection. Fresh foods were purchased in a supermarket, agrocery, and a street market and combined to composites. Processed foods were purchased additionally. Sampling was carried out in spring, summer, winter, and spring of the following year. Quercetin levels in the edible parts of most vegetables were generally below 10 mg/kg except for onions (284-486 mg/kg), kale (110 mg/kg), broccoli (30 mg/kg), French beans (32-45 mg/kg), and slicing beans (28-30 mg/kg). Kaempferol could only be detected in kale (211 mg/kg), endive (15-91 mg/kg), leek (11-56 mg/kg), and turnip tops (31-64 mg/kg). In most fruits the quercetin content averaged 15 mg/kg, except for different apple varieties in which 21-72 mg/kg was found. The content of myricetin, luteolin, and apigenin was below the limit of detection (
Polyphenols constitute one of the most numerous and ubiquitous groups of plant metabolites and are an integral part of both human and animal diets. Ranging from simple phenolic molecules to highly polymerized compounds with molecular weights of greater than 30,000 Da, the occurrence of this complex group of substances in plant foods is extremely variable. Polyphenols traditionally have been considered antinutrients by animal nutritionists, because of the adverse effect of tannins, one type of polyphenol, on protein digestibility. However, recent interest in food phenolics has increased greatly, owing to their antioxidant capacity (free radical scavenging and metal chelating activities) and their possible beneficial implications in human health, such as in the treatment and prevention of cancer, cardiovascular disease, and other pathologies. Much of the literature refers to a single group of plant phenolics, the flavonoids. This review offers an overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, as well as a brief description of the chemistry of polyphenols and their occurrence in plant foods.
Strategies for food quality control and analytical methods in Europe
- F. Balestieri
- J. Harborne
Intake of potentially anticarcinogenic flavonoids and their determinants in adults in The Netherlands.
- M. Hertog
The phenolic content of fruits II. Flavonoids in fruits 2.
- W. Wildanger
Flavanones, chalcones and dihydrochalcones - nature, occurrence and dietary burden. Review.
- F. Tomás-Barberán