Article

Flavonoids in Grapefruit and Commercial Grapefruit Juices: Concentration, Distribution, and Potential Health Benefi ts

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ADDITIONAL INDEX WORDS. Citrus, Citrus paradisi, phytochemicals, polyphenolic compounds, fl avanones, fl avones, fl avo-nols, polymethoxylated fl avones Florida is the main producer of grapefruit (Citrus paradisi Macf.) in the world. Grapefruit provide not only the tradi-tional nutrients (carbohydrates, proteins, vitamins, minerals), but also phytochemicals such as fl avonoids, which are not essential for life, but may provide many health benefi ts. Flavanones are the dominant fl avonoids, and account for about 98% of the total fl avonoids in grapefruit. Major fl avanones in grapefruit are present as glycosides. In grape-fruit, identifi ed fl avanone glycosides include didymin, dihydrokaempferol glucoside, eriocitrin, naringin, poncirin, hesperidin, neohesperidin, neoeriocitrin, narirutin, narirutin-4'-glucoside, naringin-6''-malonate (open form), and naringin-6''-malonate (closed form). Flavones or fl avonols found in grapefruit include apigenin 6,8-di-C-glucoside, apigenin 7-(malonylapiosy)-glucoside, kaempferol glycoside, luteolin, myricetin, neodiosimin, quercetin, rutin, and rhoifolin. Reported polymethoxylated fl avones in grapefruit include heptamethoxyfl avone, nobiletin, and tangeretin. The presence of naringenin (an aglycone form of naringin and narirutin) in grapefruit remains controversial. Naringin is present at the highest concentration followed by narirutin, hesperidin, poncirin, neohesperidin, didymin, and quer-cetin. The presence and their concentrations of individual fl avonoids vary with grapefruit variety, fruit tissue, juice extraction method, and geographic location. Flavonoids have been linked to many health benefi ts including antioxidant, anti-infl ammatory, and anti-tumor activity. Grapefruit and grapefruit juice are a rich source of fl avonoids, especially naringin. By consuming grapefruit and grapefruit juice, individuals not only will obtain essential nutrients but also will get health-benefi cial fl avonoids. Florida is the main producer of grapefruit (Citrus paradisi Macf.) in the world, and accounts for about 48% of the world's grapefruit production (USDA Data, 2004). During the 2003–04 crop year, about 41% and 59% of Florida's grapefruit was marketed as fresh and juice, respectively, in the world. Overseas shipments accounted for approximately 54% of Florida's fresh grapefruit shipments. Japan is the major importer of Florida fresh grapefruit, accounting for about 55.4% of all overseas shipments during the 2003–04 season. Grapefruit consist of several white and pigmented varieties including 'Marsh', 'Flame', and 'Ruby Red'. Citrus fruits and juices are among the most important nutri-ent-dense foods (Rampersaud, 2007). They contain a range of important nutrients for human health such as vitamin C, vitamin A, folate, and minerals. In addition, citrus fruits and juices contain many phytochemicals including fl avonoids, carotenoids, gluca-rates, coumarins, terpenes and limonoids. Unlike the traditional nutrients (carbohydrates, proteins, vitamins, minerals), phyto-chemicals are not essential for life, but they may provide many health benefi ts, such as anti-infl ammatory and anti-tumor activity as well as inhibiting blood clots (Baghurst, 2003; Manthey and Guthrie, 2002; Middleton et al., 2000). Bioactive phytochemicals may also protect against some of the common chronic diseases such as cancer, cardiovascular diseases, degenerative eye diseases, cognitive impairment, and general damage caused by aging (Manthey and Guthrie, 2002; Middleton et al., 2000; Nair et al., 2004). This review primarily discusses the chemistry, concentra-tion, distribution, and potential health benefi ts of fl avonoids in grapefruit and commercial grapefruit juice products.

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... Naringin in GFJ has also been shown to possess antioxidant and anti-inflammatory activities. In addition to naringin a number of other flavonoids have been reported in the grapefruit juices Table 1 [27]. GFJ due to its intrinsic antioxidant and anti-inflammatory activities can potentiate and/or synergize the activity of ARI, hence the synergistic and potentiating effect of GFJ on the antioxidant and anti-inflammatory potential of ARI was studied in different H 2 O 2 groups of mice by evaluating the biochemical and inflammatory oxidative stress parameters. ...
... Naringin has several health benefits and is bioavailable as naringin aglycone (naringenin). Naringin or naringenin acts as an antioxidant, hypolipidemic, increases alcohol metabolism, anti-apoptotic, decreases risk of atherosclerosis etc [27]. It has also been reported that pro-inflammatory cytokine production decreased post antipsychotic treatments [5]. ...
... Flavonoid content in grape fruit juice[27] ...
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Background: Dependence on antipsycotic drugs like aripriprazole (ARI) is increasing at alarming rate, hence, this study was undertaken to support the hypothesis that supplementation of Citrus paradisi (Grapefruit) juice having high concentration of polyphenols might potentiate and synergize the therapeutic effect of ARI, by increasing its bioavailability and inherent antioxidant potential. These benefits together might decrease the daily dosage of the ARI and thus alleviate the possible side effects of drug. Methods: In this study the antioxidant and anti-inflammatory potential of ARI alone and in combination with GFJ was evaluated for hydrogen peroxide (H2O2) induced oxidative stress in mice. Seventy mice (4 weeks old), were randomly divided into seven groups. Group I: Control; Group II: H2O2treated; Group III; ARI treated; Group IV GFJ treated; Group V: GFJ and H2O2treated; Group VI; ARI and H2O2treated; Group VII; ARI, GFJ and H2O2treated. Serum levels of alanine aminotransferase (ALT), blood urea nitrogen (BUN), creatinine kinase (CK), creatinine and total protein were measured. Furthermore, pro-inflammatory cytokines Interleukin (IL)-1α, IL-2, IL-10 and tumor necrosis factor-α (TNF-α) concentrations were also measured. Results: The mice group that was treated with ARI, GFJ or combination of the two showed significant improvement in the H2O2altered parameters with the combination group showing more significant improvement than the ARI and GFJ alone groups indicating a synergistic and potentiating effect of the antioxidant and anti-inflammatory potential of GFJ on ARI. Conclusion: Supplementing GFJ to ARI might increase an anti-oxidative potential of ARI due to inherent antioxidant and anti-inflammatory activity of GFJ and thus could alleviate the possible dosage dependent side effects of ARI.
... However, flavonoids and limonoids were not assessed in these studies; therefore, an evaluation of the authenticity of commercial materials where no synthetic preservatives were found was not possible. In other studies [34][35][36][37][38][39][40][41][42][43][44], analysis of limonoids and limonoid glycosides from Citrus fruits and seeds were carried out, or were conducted on flavonoid compositions from various Citrus fruit, peels, or juices [45][46][47][48][49][50][51][52][53][54][55][56][57]. The present study is the first to evaluate limonoids, flavonoids, and synthetic preservatives using one method. ...
... In addition to these compounds, 3,4,9,12,14,16,17, and neodiosmin are sometimes found in grapefruit juices, or fruits parts [57]. Other Citrus species showed different flavonoid patterns. ...
Article
A selective UHPLC-DAD-QToF-MS method was developed to screen grapefruit seeds, and the seeds of other Citrus species for limonoid aglycones, acids, glucosides, and flavonoids. These classes of compounds were identified in positive and negative ion modes over a mass-to-charge range from 100-1500. Accurate mass values, elution times, and fragmentation patterns obtained by QToF-mass spectrometry were used to identify or tentatively characterize the compounds detected in the sample of this study. Limonin was the major limonoid in most of the seeds of Citrus species, followed by nomilin. This analytical method was successfully applied for the analysis of commercial extracts and dietary supplements claiming to contain grapefruit seed extract, or extracts made from the seed and other fruit parts such as the peel or pulp. Many commercial products contained large numbers of flavonoids, indicating the use of peel, pulp, or seed coat. This method also permitted detection of synthetic preservatives such as benzethonium chloride, methylparaben, and triclosan in commercial grapefruit seed extract products. Out of the 17 commercial products analyzed, two contained the synthetic antimicrobial agent benzethonium chloride. Georg Thieme Verlag KG Stuttgart · New York.
... Flavonoids have a wide variety of pharmacological activities such as anti-inflammatory [2], antiviral [3], antiallergenic [4], vasodilator [5], which are mainly related to their high antioxidant capacities [6], besides providing protection against cardiovascular diseases and complementary treatment in several types of cancer [7]. The generic flavonoid's structure consists of three rings, two phenyl rings A and B linked by a pyrone ring C, the structure of the latter classifies them into six different subclasses: flavones, flavonols, flavanones, catechins (flavanols), anthocyanidins and isoflavonoids [8]. The flavones include apigenin present in onion and parsley [9] with antioxidant and antitumorigenic activity [10], and luteolin which is one of the coarsest compounds in medicinal and edible plants having antioxidant and anti-inflammatory activities [11]. ...
... Other important phytochemicals correspond to flavanones such as naringenin and eriodictyol present in a great variety of citric fruits and vegetables [17], being the lemon the most abundant source of the earliest, which has demonstrated to have a great variety of pharmacological and biological activities [18]. Naringenin is also found in grapes, grapefruits, tomatoes besides of citrics [11,19,20], mainly obtained from agricultural wastes [6]. 1 3 This phytochemical is of particular interest owing to several pharmacological activities of interest such as antioxidant activity, anticancer, anti-inflammatory, vasodilator and also lowers the cholesterol levels [3,8,9,17,21]. Noteworthy, the antioxidant activity for flavonoids is associated to the hydroxyl moieties in the B ring [22], thereby the increase of the antioxidant activity in the flavonoids is directly proportional to the degree of hydroxylation [10,11,23]. ...
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The bioconversion process of bioactive naringenin by whole-cells of Yarrowia lipolytica 2.2ab for the production of increased value-added compounds is successfully achieved in surface and liquid cultures. This approach is an alternative to the commercial production of these bioactive compounds from vegetable sources, which are limited due to their low concentrations and the complexity of the purification processes. The experimentation rendered seven value-added compounds in both surface and liquid bioconversion cultures. Some of the compounds produced have not been previously reported as products from the bioconversion processes, such as the case of ampelopsin. Biosynthetic pathways were suggested for the naringenin bioconversion using whole-cells of Y. lipolytica 2.2ab. Finally, the extracts obtained from the naringenin bioconversion in liquid cultures showed higher percentage of inhibition of DPPH· and ABTS· radicals up to 32.88 and 2.08 times, respectively, compared to commercial naringenin.
... Citrus fruits are important crops, which produced worldwide [1,2]. Traditionally, the by-products of citrus fruits such as pulps, seeds, and peels represent a problem in their disposal because these wastes were burned, which produced carbon dioxide and other harmful gases [1]. ...
... Citrus fruits are important crops, which produced worldwide [1,2]. Traditionally, the by-products of citrus fruits such as pulps, seeds, and peels represent a problem in their disposal because these wastes were burned, which produced carbon dioxide and other harmful gases [1]. However, new ecofriendly approcahes have been developed now HPTLC assay [36]. ...
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Hesperidin (HSP) is a bioactive flavanone glycoside, present abundantly in the variety of citrus fruits. The environmental safety and sustainability of the reported analytical assays of HSP analysis have not been considered in the literature. Hence, a sensitive and sustainable “reversed-phase high-performance thin-layer chromatography (RP-HPTLC)” method has been developed and validated for HSP analysis in traditional (TE) and ultrasound-based (UBE) extracts of four different varieties of citrus fruit peels and its commercial tablet dosage forms. The binary combination of green solvents such as ethanol-water (50:50, v v−1) was used as the mobile phase. The detection of HSP was performed at 287 nm. The sustainable RP-HPTLC method was linear in 20–2000 ng band−1 range. The studied validation parameters, including accuracy, precision, robustness, sensitivity were acceptable for HSP analysis. The content of HSP in TE of four different varieties of citrus fruits including grapefruit peels (Citrus paradisi), mosambi peels (Citrus limetta), lemon peels (Citrus lemon), and orange peels (Citrus sinensis) was detected as 8.26, 6.94, 5.90, and 6.81% w w−1, respectively. The content of HSP in TE of commercial formulations A and B was detected as 5.31 and 5.55% w w−1, respectively. However, the content of HSP in UBE of grapefruit peels, mosambi peels, lemon peels, and orange peels was detected as 11.41, 8.86, 7.98, and 8.64% w w−1, respectively. The content of HSP in UBE of commercial formulations A and B was detected as 6.72 and 6.92% w w−1, respectively. The greenness score of the sustainable RP-HPTLC method was predicted as 0.83 using analytical GREEnness (AGREE) metric approach, indicated the excellent greenness profile of the RP-HPTLC method. UBE procedure for HSP was superior over its TE procedure. These observations and results suggested that the present RP-HPTLC method can be successfully used for the quantitative estimation of HSP in the variety of citrus fruit peels and its commercial formulations. In addition, this method is simple, rapid, precise, accurate, and economical compared to the reported analytical methods of HSP analysis. It is also safe and sustainable method due to the use of ethanol-water solvents systems, as both the solvents are green solvents compared to the solvents used in reported analytical methods of HSP analysis.
... Citrus fruit is nutrient-dense with vitamins, folate, phytochemicals like flavonoids, carotenoids, coumarins, terpenes, and limonoids (Rampersaud, 2007;Zhang, 2007). Grapefruit is recognized as a functional food, valued in certain cultures as promoting health due to the flavonoid compounds present in the fresh fruit and the juice (Kiani and Imam, 2007;Tundis et al., 2014;Yu et al., 2005;Zou et al., 2016). ...
... Flavonoids consist of two benzene rings and an oxygenated heterocycle pyrone ring. Six dietary flavonoids are recognized: flavones, flavonols, flavanones, flavanols (catechins), anthocyanins, and isoflavonoids (Zhang, 2007). Citrus has four types of the flavonoids: flavanones (about 98%), and smaller amounts of flavones, flavonols, and anthocyanins (Benavente-Garcia et al., 1997). ...
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Grapefruit [ Citrus × aurantium (synonym C. × paradisi )] is an important citrus commodity that originated in Barbados in the 17th century. Grapefruit is the youngest member of the genus Citrus . Most commercially important grapefruit cultivars arose through natural and induced mutations, not traditional breeding, of the white-fleshed and seedy Duncan grapefruit. Now, cultivars with a range of flesh colors exist; the pigmentation is correlated with lycopene content. A bud sport mutant of grapefruit discovered in Texas has a deep golden-colored flesh, significantly different from the typical reddish pigmentation. In this review, we discuss grapefruit’s journey from its origin in Barbados and its global establishment including production, marketing, drug interactions, cultivar development, genetic diversity, and commercially significant cultivars.
... Like its glycoside naringin, naringenin is present in grapefruit. Its concentration in grapefruit juice ranges from 0 to 12.6 mg/100 mL (Zhang, 2007). Both flavonoids also occur in tomatoes (Bugianesi et al., 2002), and in oranges (Kumpulainen et al., 1999;Erlund, 2004;e Silva et al., 2014) (Table 3). ...
... mg/100 mL in orange juice (c) (a): Bugianesi et al. (2002). (b): Zhang (2007). (c): e Silva et al. (2014). ...
Article
The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) of EFSA was requested to deliver a scientific opinion on the implications for human health of the flavouring substance 40,5,7-trihydroxyflavanone or naringenin [FL-no: 16.132], in the Flavouring Group Evaluation 410 (FGE.410), according to Regulation (EC) No 1331/2008 of the European Parliament and of the Council. The substance occurs naturally in grapefruits, oranges and tomatoes. It is intended to be used as a flavouring substance with flavour-modifying properties in specific categories of food. Information on specifications and manufacturing of [FL-no: 16.132] were considered adequate; however, data on stability in food are incomplete. The Panel noted that the available genotoxicity studies have significant shortcomings and are insufficient to conclude on the genotoxic potential of naringenin. Therefore, [FL-no: 16.132] cannot be evaluated through the Procedure. Additionally, the Panel noted that inhibition of CYP 450 by [FL-no: 16.132] has been clearly demonstrated in animal species in vivo which implies that the substance may interact with the metabolism and elimination of medicines and no convincing information is available that this does not pose a risk to humans at the estimated levels of exposure. To continue with the safety assessment of [FL-no: 16.132], a bacterial gene mutation assay and an in vitro micronucleus assay (according to OECD guidelines 471, 487 and GLP) are required. Even if these studies do not indicate a genotoxic potential, additional toxicological data are needed to finalise the evaluation.
... Narenciye meyve suları içinde naringin miktarı en yoğun altıntopta görülürken, portakal suyunda çok daha az miktarda bulunmakta ve ilaçlarla etkileşim durumu görülmemektedir (Rodvold and Meyer 1996). Altıntoplarda en çok bulunan flavonoid olan glycoside naringin'in, yapılan bir çalışmada altıntop suyunda farklı gruptaki flavonoidler içerisinde en yüksek miktara sahip flavonoid olduğu saptanmıştır (Zhang 2007). Yapılan başka bir çalışmada da, beyaz renkli altıntop çeşitlerinden olan Marsh seedless ve Duncan çeşitleri ile renkli bir çeşit olan Star Ruby çeşidi kıyaslandığında, en yüksek naringin oranına Marsh seedless çeşidinin sahip olduğu ve en düşük naringin oranın ise Duncan çeşidinde görüldüğü belirtilmiştir (Mansell et al. 1983 ...
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Population fluctuation of Ceratitis capitata Wied. (Diptera: Tephritidae) in grapefruit orchards and effect of temperature on its development Mediterranean fruit fly, Ceratitis capitata Wied. (Diptera: Tephritidae),turned into important pest of grapefruit in the last decade. As a result of changing consumer behavior in the fruit market, unsold or unripen grapefruits become favored food source for C. capitata in every spring. Therefore, population fluctuations in three different grapefruit orchards, Marsh seedless, Rio Red, and Star Ruby, through 2013-2015 in Balcalı, Adana and effect of temperature on development time from egg to adult stage in Rio Red variety at laboratory conditions was investigated. The highest population peaks were observed on Marsh seedless in
... Zhang reported 10.1 -86.7 mg/100 mL concentration of naringin in commercial juices and 7.3 -30.7 mg/100 mL naringin in hand-extracted ones. The albedo exhibited the highest concentration of naringin 490 -4100 mg/100 mL [20]. Similarly, Peterson et al. reported different naringin values for grapefruit juice, depending on the type of grapefruit: white, from 0 to 43.22 mg/100 mL and red from 3.28 and 48.89 mg/100 mL [13]. ...
Article
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Functional foods like citrus fruits contain a range of nutrients and phytochemicals like flavonoids that are important for human health. Using a LC/MS method, this study investigates the concentration of naringin and naringenin in 36 citrus juices (orange, tangerine, pomelo, white, pink, and red grapefruit) that are commercially available or freshly prepared in the laboratory. Among the freshly prepared grapefruit juices, the red grapefruit juice prepared from pulp and albedo exhibited the highest concentration of naringin (332.02 mg/L). In commercially available juices, the average naringin content was 89.23 ± 107.80 mg/L. In conclusion, both citrus juices prepared in the laboratory and commercially available present a great variability of naringin content. © 2017, Romanian Society for Pharmaceutical Sciences. All rights reserved.
... For example, the market price for flavonoid compounds such as naringenin used in analytical experimentation can amount to USD 248/g. In commercially available grapefruit juices, naringenin content can only reach up to 0-12.6 mg/100 mL [22]. Thus, the production of a vast amount of these expensive products could positively influence the business sectors dedicated towards flavonoid production. ...
Article
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Flavonoids are polyphenols that are important organic chemicals in plants. The health benefits of flavonoids that result in high commercial values make them attractive targets for large-scale production through bioengineering. Strategies such as engineering a flavonoid biosynthetic pathway in microbial hosts provide an alternative way to produce these beneficial compounds. Escherichia coli, Saccharomyces cerevisiae and Streptomyces sp. are among the expression systems used to produce recombinant products, as well as for the production of flavonoid compounds through various bioengineering approaches including clustered regularly interspaced short palindromic repeats (CRISPR)-based genome engineering and genetically encoded biosensors to detect flavonoid biosynthesis. In this study, we review the recent advances in engineering model microbial hosts as being the factory to produce targeted flavonoid compounds.
... Naringin, a flavanone diglycoside, is the main component responsible for the bitter taste of citrus fruits. Based on the available scientific publications, the concentration of naringin in commercial and fresh grapefruit juice ranges from 104 to 867 µg mL −1 (0.179-1.493 mM) [1][2][3][4][5][6] and depends on grapefruit variety, grapefruit maternity, and juice extraction method. Although the concentration of naringin in grapefruit juice is low, it imparts a perceptible bitter taste to consumers. ...
Article
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Naringinase is an enzyme complex which exhibits α-l-rhamnosidase and β-d-glucosidase activity. This enzymatic complex catalyzes the hydrolysis of naringin (4′,5,7-trihydroxy flavanone 7-rhamnoglucoside), the main bittering component in grapefruit. Reduction of the level of this substance during the processing of juice has been the focus of many studies. The aim of the study was the immobilization of naringinase on chitosan microspheres activated with glutaraldehyde and, finally, the use of such immobilized enzyme for debittering grapefruit juice. The effect of naringinase concentration and characterization of the immobilized enzyme compared to the soluble enzyme were investigated. The maximum activity was observed at optimum pH 4.0 for both free and immobilized naringinase. However, the optimum temperature was shifted from 70 to 40 °C upon immobilization. The KM value of the immobilized naringinase was higher than that of soluble naringinase. The immobilization did not change the thermal stability of the enzyme. The immobilized naringinase had good operational stability. This preparation retained 88.1 ± 2.8% of its initial activity after ten runs of naringin hydrolysis from fresh grapefruit juice. The results indicate that naringinase immobilized on chitosan has potential applicability for debittering and improving the sensory properties of grapefruit juices.
... fruit origin, fruit variety, manufacturing procedures, storage conditions. . .) but also variation in the degree of maturity of the fruit (Nogata et al., 2006;De Castro et al., 2006;Del Río et al., 1997;Ho et al., 2000;Zhang, 2007). ...
Article
Initiative of waste treatment has to be based on user-friendly technologies, using robust, cost-effective and low-energy consuming processes. The global objective of this study was to reduce technical steps for the extraction of flavonoids (naringin and narirutin) from citrus peel (grapefruit peel). After a first fresh peel grinding, the relevance of a simple filtration-compression, as a first downstream process, of the obtained slurry was studied. An optimization of this solid-liquid separation was proposed and the impact of a pectinolytic enzymatic treatment, resulting potentially in a larger release of flavonoids, was investigated. The results demonstrated that a preliminary step of filtration-compression, directly realized on fresh grinded peels as downstream processing for flavonoids extraction could be pertinent and that the enzymatic treatment improved the slurry filterability. An optimal separation was obtained with a transmembrane pressure of 5 bar, leading to highest extractable liquid phase volume and to an extraction around 80% of naringin and narirutin. A modelling of the filtration step, essential for the scaling of a filtration-compression process on site, was proposed. An originality of this work was to identify the dispersion state of the flavonoids within the liquid phase, capital identification for a relevant choice of the subsequent extraction step of these compounds.
... The exceptional supplement of those tested was CBF-6 that contained mostly naringin (84.08%) and hesperidin (14.25%). This flavonoid profile suggested grapefruit as the main citrus source since naringin is the predominant flavonoid in grapefruit [6]. There are known interactions between flavonoids and furanocoumarins from grapefruit with various drugs, primarily due to inhibition of CYP3A4. ...
Article
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Citrus bioflavonoids are polyphenolic plant-derived pigments found in high levels in oranges, lemons, grapefruits and other citrus fruits. The three most abundant types of citrus bioflavonoids are hesperidin, naringenin and eriocitrin. Citrus bioflavonoids have long been known to possess powerful free radical-scavenging properties and cardioprotective effects. The study involved the analysis of 10 commercially available citrus bioflavonoid supplements from three different countries: Australia, the United States and Canada. The supplements were tested for their citrus bioflavonoid content which varied from 0.8 to 33.3% w/w. The daily bioflavonoid dose varied from 19 mg to 560 mg. Hesperidin was the major citrus bioflavonoid in nine out of ten supplements. One supplement was found to contain less than 10% of the quantity of rutin claimed to have been added. The DPP-4 inhibitory potential, compared through an estimation of rutin equivalence, ranged from 1.9 mg to 400 mg per day. This data highlights the variability between the supplements in their potential to inhibit DPP-4 for subsequent health benefits.
... Indeed, we found the amount of naringin in the CL fruit juice 237.1% higher (0.83 ± 0.04 g/L) than in the KF fruit juice (0.35 ± 0.01 g/L) and 259.4% higher than the JCR (0.32 ± 0.03 g/L). Interestingly, the results of the content of naringin in Citrus bergamia fruits were comparable to grapefruit, well-known as the prevalent flavonoid in the juice (Zhang, 2007). Another important deviation between KF and CR with CL fruits regards neohesperidin content. ...
Article
The present study describes the peculiar phytochemical characteristics of bergamots cultivated in distinct islands of the Ionian Sea. Ultrahigh-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS) supported by 1 and 2D NMR spectroscopy was used for unambiguous metabolic profiling of albedo, flavedo and juice samples. Profile differences were determined using a multi-analytical clustering approach based on high-performance thin-layer chromatography fingerprints and UHPLC-HRMS data. Finally, a validated HPLC method offering good precision (0.12–0.94%) and accuracy (95.25–103.93%) was proposed for the quantification of the major flavanones. A total of 37 secondary metabolites were characterized belonging to flavonoids, limonoids and coumarins. Their distribution was tissue-dependent and varied significantly from bergamots of other geographical locations. Surprisingly, neoeriocitrin was the major flavanone, reaching 1.69 ± 0.05 g/L in the juice and 5.24 ± 0.12 mg/g in albedo. This is the highest reported amount among Citrus species, rendering Ionian bergamots a promising candidate for novel functional products.
... Flavonoids are mostly present in plants as glycosides. Four types of flavonoids were found in citrus: flavanones, flavones, flavonols and anthocyanins [53]. The flavonoids of citrus fruit contains collection of glycosides, i.e, hesperidin and naringin and an additional group of Omethylatedaglycones of flavones for example nobiletin and tangeretin, these are two widespread polymethoxylated flavones (PMFs) [55]. ...
Article
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Plants are natural source of valuable products for benefits of human health. It is important source of phytochemical compounds having antioxidant, antimicrobial properties which may be applicable in different therapeutic applications. The plants of Citrus belongs to Rutaceae family, the most common plants of this family are orange, lime, mandarin, sour orange, lemon and grapefruit having numerous beneficial nutrients consumed by human beings. The citrus fruits have various pharmacological properties and its constituents are broadly utilized for many clinical applications. Conventionally these fruits have been extensively used in the treatment of the several disorders such as diabetes, scurvy, urinary disorder, indigestion and constipation, ulcers and also applicable for improvement of immune system. In this review, comprehensive study focused on some phytochemical compounds and the pharmacological activities present in some citrus fruits and its peel, which is has discarded as waste has been focused.
... Narirutin is the conformational isomer of naringin (33). The monosaccharides in narirutin are joined together through -1,6 glycosidic linkage. ...
... Current production processes mostly depend on petroleum-based chemical processes (Das et al., 2007) or direct extraction from plants (Trantas et al., 2015). However, the chemical processes involved are often inefficient and unsustainable (Chemler and Koffas, 2008;Bhan et al., 2013;Zha et al., 2019) while plant extraction processes are limited by biomass availability, low extraction yields and low purity of the final products (Zhang, 2007;Rodriguez et al., 2017). To overcome these pitfalls and meet the increasing demand for biologically and renewably sourced aroma and flavour compounds, microbial production from renewable feedstocks offers a promising alternative (Trantas et al., 2015). ...
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Engineered strains of the yeast Saccharomyces cerevisiae are intensively studied as production platforms for aromatic compounds such as hydroxycinnamic acids, stilbenoids and flavonoids. Heterologous pathways for production of these compounds use l-phenylalanine and/or l-tyrosine, generated by the yeast shikimate pathway, as aromatic precursors. The Ehrlich pathway converts these precursors to aromatic fusel alcohols and acids, which are undesirable by-products of yeast strains engineered for production of high-value aromatic compounds. Activity of the Ehrlich pathway requires any of four S. cerevisiae 2-oxo-acid decarboxylases (2-OADCs): Aro10 or the pyruvate-decarboxylase isoenzymes Pdc1, Pdc5, and Pdc6. Elimination of pyruvate-decarboxylase activity from S. cerevisiae is not straightforward as it plays a key role in cytosolic acetyl-CoA biosynthesis during growth on glucose. In a search for pyruvate decarboxylases that do not decarboxylate aromatic 2-oxo acids, eleven yeast and bacterial 2-OADC-encoding genes were investigated. Homologs from Kluyveromyces lactis (KlPDC1), Kluyveromyces marxianus (KmPDC1), Yarrowia lipolytica (YlPDC1), Zymomonas mobilis (Zmpdc1) and Gluconacetobacter diazotrophicus (Gdpdc1.2 and Gdpdc1.3) complemented a Pdc⁻ strain of S. cerevisiae for growth on glucose. Enzyme-activity assays in cell extracts showed that these genes encoded active pyruvate decarboxylases with different substrate specificities. In these in vitro assays, ZmPdc1, GdPdc1.2 or GdPdc1.3 had no substrate specificity towards phenylpyruvate. Replacing Aro10 and Pdc1,5,6 by these bacterial decarboxylases completely eliminated aromatic fusel-alcohol production in glucose-grown batch cultures of an engineered coumaric acid-producing S. cerevisiae strain. These results outline a strategy to prevent formation of an important class of by-products in ‘chassis’ yeast strains for production of non-native aromatic compounds.
... The glycosylated flavones are present in small quantities in Citrus peel, such as diosmin, rhoifoline, isorhoifoline, luteolin. Other flavonoids are present in very small quantities in citrus peel, such as flavonols (quercetin, rutin, myricetin, and kaempferol) [39]. ...
Article
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Citrus species are one of the world's popular fruit crops, cultivated all over the world for their economic and nutritional values. Citrus, like other fruits and vegetables, are an important source of several antioxidant molecules (polyphenols, ascorbic acid, and carotenoids) that can inhibit the harmful effects of free radicals on the human body; due to their functional values and health-promoting properties, Citrus species are considered valuable fruits not only in agri-food industry , but also in pharmaceutical industry. Flavonoids are among the major constituents of poly-phenols found in different parts of Citrus fruits (skin, peels, seed, pulp membrane, and juice). Fla-vonoids have different biological properties (antiviral, antifungal, and antibacterial activities). Several studies have also shown the health-related properties of Citrus flavonoids, especially antioxi-dant, anticancer, anti-inflammation, anti-aging, and cardiovascular protection activities. In the present review, attempts are made to discuss the current trends of research on flavonoids in different Citrus species.
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The grapefruit is one of the most produced and consumed citrus fruits in the world, with an average annual production of 7 million tonnes. It has become increasingly popular, as it is considered a low-calorie fruit, rich in vitamins, minerals and many other valuable nutrients (flavonoids, carotenoids, essential oils…). Over half a million tonnes of grapefruit undergo processing, mainly into juice, which generates large amounts of wastes (peel, seeds, pulp and leftover membrane), since only 50% of the fruit is used in this manufacturing process. Today, these wastes are mostly discarded or used as cattle feed. These practices are unfortunate, as grapefruit processing wastes could be a source of high-added economic value. Indeed, they represent a source of dietary fibers, sugars, essential oils, flavonoids and carotenoids, valuable in various industrial sectors (energetic, agricultural, pharmaceutical, cosmetic and food). Thus, if grapefruit wastes can be used to produce biogas or bio-energy, to fertilize soil or as biosorbent in wastewater treatment, the recovery of their bioactive compounds (e.g. pectin, essential oils, carotenoids and flavonoids) could be also highly pertinent, as these compounds present a wide spectrum of technological properties and/or health benefits. Extraction processes usually adopted to recover those compounds use organic solvents, high temperatures and long extraction times, which are considered to generate a high environmental impact. As a result, in recent decades, different operating strategies have been developed (ultrasound-, microwave-, pulsed electric field-assisted extraction, and supercritical fluids), with the objective of increasing extraction yields while reducing use of resources. However, most of them have still economic or technological limitations that prevent their development in small and medium-sized enterprises. The present chapter expands on the aforementioned aspects of grapefruit wastes, with the objective of demonstrating their high re-use potential. This chapter presents the potential valorization of grapefruit wastes in food and non-food applications and offers a brief overview of the main emergent extraction technologies.
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A glassy carbon electrode (GCE) modified with polyaminobenzene sulfonic acid functionalized single-walled carbon nanotubes (f-SWCNT) and electropolymerized aluminon has been developed for the simultaneous determination of naringin and hesperidin. Polyaluminon has been obtained by potentiodynamic electrolysis in basic medium from 100 µmol L⁻¹ monomer solution by 10-fold potential cycling from 0.1 to 0.8 V at potential scan rate of 100 mV s⁻¹. The polyaluminon-based electrode provides a statistically significant increase in the naringin and hesperidin oxidation currents at the same potentials in comparison to the electrode modified with carbon nanotubes. The electrode has been characterized by scanning electron microscopy (SEM) and electrochemical methods. The polyaluminon-modified electrode has demonstrated a 1.5-fold increase in the effective surface area compared to the f-SWCNT/GCE as well as a 2.1-fold lower electron transfer resistance. The electrooxidation parameters of hesperidin and naringin, including the anodic transfer and diffusion coefficients and number of electrons, have been determined. Differential pulse voltammetry in phosphate buffer (PB) pH 5.0 has been employed for the simultaneous determination of naringin and hesperidin. The linear dynamic ranges from 0.10 to 2.5 and 2.5 to 25 µmol L⁻¹ have been obtained for the both analytes with the detection limits of 0.020 and 0.029 µmol L⁻¹ for naringin and hesperidin, respectively. The method has been employed for the analysis of orange and grapefruit juice.
Article
In the present work, enzymes pectinase and naringinase were simultaneously co-immobilized on an eco-friendly chitosan coated magnetic nanoparticles (chitosanMNPs) by cross-linking using chitosan as a macro-molecular cross-linker. The maximum activity recovery of both enzymes in the co-immobilized form was obtained at chitosanMNPs to enzymes ratio of 1:3, 3% cross-linker concentration and 150 min cross-linking time. The synthesized MNPs before and after co-immobilization were characterized using different techniques. The prepared biocatalyst was found spherical with an average size below 200 nm and showed supermagnetic property with saturation magnetization of 38.28 emu/g. The optimum pH and temperature of both enzymes in co-immobilized form was found at 5.5 and 65 °C. The prepared biocatalyst exhibited an improved thermal stability with 1.8-fold increase in the half-life. The secondary structural analysis revealed that, prepared co-immobilized biocatalyst undergone changes in the conformational and structural rigidity due to macro-molecular cross-linker. The co-immobilized biocatalysts were evaluated for one pot clarification and debittering of grapefruit juice and found ~52% reduction in turbidity and ~85% reduction in the naringin content. The co-immobilized enzymes were recycled up to 7th cycle and can be easily stored at room temperature for 30 days retaining up to 64% and 86% residual activities respectively.
Article
About 90% grapefruits in Florida are affected by Huanglongbing (HLB). HLB negatively affects organoleptic properties of grapefruit juice because infected trees overproduce bitter secondary-metabolites, mostly naringin. The objective was to remove naringin from HLB-affected grapefruit juice using microporous-adsorbents and to investigate how debittering affects narirutin, limonoids, bergamottin, and consumer acceptability. The adsorption kinetics of naringin on seven adsorbent resins obeyed pseudo-second order. PAD550 and PAD600 showed better static adsorption/desorption. Adsorption-isotherms on these resins were better fitted on Temkin-Pyzhev-model. On a fixed-bed-column packed with PAD550 resin, a slower loading rate increased its breakthrough volume before naringin in effluent reached its taste-threshold. In addition to naringin being reduced to below its taste-threshold, debittering significantly decreased the content of limonin, nomilin, and bergamottin. A consumer taste panel rated debittered and half-debittered juices higher for overall acceptability than the untreated. The half-debittered juice was ranked the most preferred while untreated was the least preferred.
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Citrus co‐products are rich in flavonones among them naringin. This compound exhibits several biological activities. These properties are mainly due to its antioxidant activity. The purpose of this work was in one hand to compare five technics of extraction conducted under different operating conditions and in the other hand, to analyse the effects of temperature, light and oxygen on naringin degradation and on the evolution of its antioxidant activity. The results obtained showed that the ultrasound assisted extraction leads to the highest naringin content and the thermal degradation of naringin occurs only for higher temperatures above 100 °C. Moreover, the naringin appears to be sensitive to an exposure to visible light (16.5 klux). The effect of the oxygen is less pronounced due to the lack of the enone structure and a hydroxyl group in position 3. The antioxidant activity of naringin is significantly affected by the light and high temperature. Effect of the extraction process and the temperature on the naringin content.
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Due to the prevalence of individuals suffering from chronic wounds, developing safe and effective wound care agents are one of the more prominent fields of research in biology. However, wound healing is a complex, multi-stage biological process, involving multiple sequences of biological responses from different types of cells, secreted mediators, and extracellular matrix elements. Plants have a long history of use in the treatment of wounds. Plant-derived extracellular vesicles, which are secreted nano vesicle messengers responsible for intercellular communications, show promise as a new, biotechnological wound-care agent. In this study, we assessed the wound healing potential of extracellular vesicles isolated from grapefruits - a plant with well-known anti-inflammatory and wound healing properties. Grapefruit extracellular vesicles (GEVs) increased cell viability and cell migration while reducing intracellular ROS production in a dose-dependent manner in HaCaT cells. Expression of proliferation and migration-related genes were raised by GEV treatment in a dose dependent manner. Additionally, GEV treatment increased the tube formation capabilities of treated HUVEC cells. These findings suggest that GEVs can be used as plant-derived wound healing agents, and have shown potential as a biotechnological agent for wound healing. Further development and study of plant-derived extracellular vesicles may lead to the realization of their full potential.
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Citrus peel is rich in functional ingredients such as essential oils (0.6 to 1%), fibers (6.30-42.13 g/100g db), phenols (0.67 to 19.62 g/100 g db) and vitamin C (0.109 to 1.150 g/100g db). Flavanones (hesperidin: 0.002-80.90 mg/g db, neohesperidin: 0.05-11.70 mg/g db, narirutin: 0.03-26.90 mg/g db; naringin: 0.08-14.40 mg/g db) and polymethoxylated flavones (sinensetin: 0.08-0.29 mg/g db, nobiletin: 0.20-14.05 mg/g db, tangeretin: 0.16-7.99 mg/g db) are the main phenolic compounds of citrus peel. Due to their antioxidant activity, phenolic compounds are used in various applications such as formulation of healthy food, cosmetic, and pharmaceutical products. Phenolic compounds present sensitivity to process operating conditions (during juice processing and further thermal and nonthermal processing). This review summarizes the main publications dealing with the proximate chemical composition, the functional properties and the potential applications of the main citrus peel compounds. The effects of conventional and nonconventional processing on phenolic compounds of citrus fruits and their derived and coproducts are analyzed. The information provided in this review allows a better choice of appropriate processes and their optimal operating conditions for a better retention of antioxidants in citrus products.
Article
Degreening early season grapefruits using ethylene helps to accelerate peel color change resulting in uniformly colored, attractive and marketable fruits. In current study, phytochemicals and flavonoid-pathway genes were studied in early season grapefruits degreened using 5 ppm and 10 ppm ethylene and stored for 35 days under market-simulated conditions. Ethylene treatment and concentration had significant influence during initial treatment and storage weeks on expression of genes involved in the flavonoid biosynthesis pathway, namely phenylalanine ammonia lyase, chalcone synthase, chalcone isomerase, and 1,2-rhamnosyltransferase. Ethylene treated fruits showed lower expression of flavonoid-pathway genes during three days of degreening treatment. Lycopene, vitamin C, and 6,7-dihydroxybergamottin were higher in non-degreened and 10 ppm treatment at the end of 35 days of storage. On the other hand, flavonoids and β- carotene were higher in 10 ppm degreened fruits. Significant effect of ethylene concentration was observed in flavonoids and furocoumarins at end of storage. At 7 days of storage after the fruits were removed from the ethylene treatment, flavonoids were significantly lower in degreened fruits. In conclusion, significant effect of ethylene degreening and ethylene concentration was observed on phytochemicals and flavonoid pathway genes in Rio Red grapefruit.
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In order to develop a database for flavanones, the dominant flavonoid class in the genus citrus, the relevant scientific literature on flavonoids in grapefruit, lemons, and limes was searched, abstracted, documented, standardized by taxons and units (mg/100 g) and examined for quality. Values for eight flavanones (didymin, eriocitrin, hesperidin, naringin, narirutin, neoeriocitrin, neohesperidin, poncirin) are presented. Grapefruit had a total flavanone content (summed means) of 27 mg/100 g as aglycones and a distinct flavanone profile, dominated by naringin. White grapefruit varieties tended to be slightly but not significantly higher in total flavanones than pink and red varieties. For lemons, total flavanones (summed means) were 26 mg/100 g and for limes 17 mg/100 g. The flavanone profiles of both lemons and limes were dominated by hesperidin and eriocitrin.
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Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.
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Flavonoids are effective antioxidants and may protect against several chronic diseases. The association between flavonoid intake and risk of several chronic diseases was studied. The total dietary intakes of 10 054 men and women during the year preceding the baseline examination were determined with a dietary history method. Flavonoid intakes were estimated, mainly on the basis of the flavonoid concentrations in Finnish foods. The incident cases of the diseases considered were identified from different national public health registers. Persons with higher quercetin intakes had lower mortality from ischemic heart disease. The relative risk (RR) between the highest and lowest quartiles was 0.79 (95% CI: 0.63, 0.99: P for trend = 0.02). The incidence of cerebrovascular disease was lower at higher kaempferol (0.70; 0.56, 0.86; P = 0.003), naringenin (0.79; 0.64, 0.98; P = 0.06), and hesperetin (0.80; 0.64, 0.99; P = 0.008) intakes. Men with higher quercetin intakes had a lower lung cancer incidence (0.42; 0.25, 0.72; P = 0.001), and men with higher myricetin intakes had a lower prostate cancer risk (0.43; 0.22, 0.86; P = 0.002). Asthma incidence was lower at higher quercetin (0.76; 0.56, 1.01; P = 0.005), naringenin (0.69; 0.50, 0.94; P = 0.06), and hesperetin (0.64; 0.46, 0.88; P = 0.03) intakes. A trend toward a reduction in risk of type 2 diabetes was associated with higher quercetin (0.81; 0.64, 1.02; P = 0.07) and myricetin (0.79; 0.62, 1.00; P = 0.07) intakes. The risk of some chronic diseases may be lower at higher dietary flavonoid intakes.
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Free radicals are responsible for the induction of damage to the cellular DNA that leads to the formation of chromosome aberrations. Antioxidants are known to scavenge free radicals, thereby decreasing the degree of such effects. Radiation is a well-known inducer of free radicals and compounds that can scavenge free radicals may reduce radiation-induced DNA damage. Naringin, a bioflavonoid predominant in grapefruit and other citrus fruits, has been found to scavenge free radicals, therefore it may also reduce radiation-induced damage. The aim of the present study was to evaluate the radioprotective action of 2 mg/kg naringin in the bone marrow of mice exposed to different doses of (60)Co gamma-radiation by scoring the frequency of asymmetrical chromosomal aberrations. The irradiation of mice resulted in a dose-dependent elevation in the frequency of aberrant cells, acentric fragments, chromatid and chromosome breaks, dicentrics and exchanges. All these aberrations were elevated with scoring time up to 24 h post-irradiation and declined thereafter, except chromatid breaks, which were maximum at 12 h post-irradiation. Treatment of mice with 2 mg/kg body wt naringin before exposure to various doses of gamma-radiation resulted in a significant reduction in the frequencies of aberrant cells and chromosomal aberrations like acentric fragments, chromatid and chromosome breaks, centric rings, dicentrics and exchanges. The evaluation of free radical scavenging activity of naringin revealed a dose-dependent scavenging of hydroxyl, superoxide and 2,2 equal to or precedes -diphenyl-1-picryl hydrazyl radical. Naringin at 5 microM scavenged the 2,2-azino-bis-3-ethyl benzothiazoline-6-sulphonic acid cation radical very efficiently, where a 90% scavenging was observed. Our study demonstrates that naringin can protect mouse bone marrow cells against radiation-induced chromosomal damage.
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Naringin and naringenin protect hemoglobin from nitrite-induced oxidation to methemoglobin. The protection is not observed when naringin and naringenin are added after the autocatalytic stage of the oxidation of hemoglobin by nitrite. The ability of naringin and naringenin to scavenge oxygen free radicals may be responsible for the action because superoxide, hydroxyl and other free radicals are implicated in promoting the autocatalytic stage of oxidation of hemoglobin by nitrite. Both compounds showed less ability to protect intact erythrocytes suggesting that they may not cross the erythrocyte membrane in sufficient amounts. Naringenin was more effective than naringin, probably because of the extra phenolic group in the aglycone.
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An HPLC analysis was performed on the concentrations of flavonoids in 42 species and cultivars of the Citrus genus and those of two Fortunella and one Poncirus species according to the classification system established by Tanaka. The composition of 8 flavanones and 9 flavone/ols for these species was determined in the albedo, flavedo, segment epidermis and juice vesicle tissues, and those in the fruit and peel tissues were calculated from the composition data of the tissues. A principal component analysis showed that such neohesperidosyl flavonoids as neoeriocitrin, naringin, neohesperidin, and rhoifolin had large factor loading values in the first principal component for each tissue. The flavonoid composition of citrus fruits was approximately the same within each section of Tanaka's system, except for the species in the Aurantium section and those with a peculiar flavonoid composition such as Bergamot (C. bergamia), Marsh grapefruit (C. paradisi), Sour orange (C. aurantium), and Shunkokan (C. shunkokan). The Aurantium section included both naringin-rich and hesperidin-rich species.
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The content of the active ingredients of grapefruit juice, naringin, naringenin and bergapten, was determined in 20 different commercial products of grapefruit juice sold in California. These included Minute Maid, Dole, Tropicana, Ocean Spray, Ralps, Albertson, Stater Bros, Vons, Langers, etc. The concentrations of naringin, naringenin and bergapten in grapefruit juice were assayed by specific HPLC methods. Naringin was found to be the most abundant flavonoid in grapefruit juice products, followed by naringenin and bergapten. The content of naringin varied among the products, ranging from 104 mg/l (Tropicana ruby red) to 628 mg/l (Ralphs white frozen concentrate). The mean contents of naringin in ruby red (158 +/- 66 [SD] mg/l) and pink (279 +/- 123 mg/l) grapefruit juice products were significantly lower than white (481 +/- 94 mg/l) (p <0.005) grapefruit juice products. Content of naringenin also varied from brand to brand and ranged from 3.9 mg/l (Vons white frozen concentrate) to 31.2 mg/l (Tree Sweet pink). Bergapten content was very low in grapefruit juice products ranging from 0 (not detectable) to 5.5 mg/l. There were no significant differences in naringenin and bergapten contents among the three types of grapefruit juice products. The information gained from this study would be useful in predicting the likelihood of grapefruit juice-drug interactions.
Article
A consistent inverse relationship between bitterness and flavor was observed during a survey of canned single-strength grapefruit juice from 1977-78 to 1979-80. During a typical season bitterness decreased, flavor increased, limonin decreased and naringin increased with fruit maturity. Highest average flavor score was observed during the 1978-79 season. This season had the lowest bitterness score, the highest Brix/acid ratio and the lowest concentrations of limonin and naringin. Four of the eleven participating plants had below average flavor scores. Each of these plants also had above average bitterness, above average limonin, below average ratio and above average acid. Only two of the four plants had above average naringin. In 1973 the Florida Department of Citrus initiated a program whose ultimate goal was to improve the quality of Florida grapefruit products, including canned single-strength grapefruit juice. One of the chief goals of the program was to determine those factors that have the most influence on the consumer preference (flavor) of grapefruit juice. Another similar goal was to develop chemical and/or physical tests for the objective measurement of these quality factors.
Article
The bioactivities, dietary sources, bioavailability, metabolism, and epidemiology of 3 flavonoids, quercetin, hesperetin, and naringenin, are reviewed. The use of their plasma concentrations as biomarkers of dietary intake is also discussed. The compounds were chosen because of their significant dietary intakes and promising bioactivities, and in the case of quercetin, because epidemiological studies suggest protection against cardiovascular disease.
Article
The cold pressed peel oils of three species of citrus fruit, viz. sweet orange, tangerine, and grapefruit, have been examined for polymethoxyflavones by GC and GC-MS. Four GC column stationary phases were compared and separation of the six predominant orange oil polymethoxyflavones was obtained isothermally at 310°C in under ten minutes, including the resolution of the polymethoxyflavones from β-sitosterol. The nature of the stationary phase and the analysis temperature exercise dramatic effects on the resolution and elution order of the components, DB-35ms providing the best overall separation. A temperature programmed separation is also presented and the polymethoxyflavone composition of all three oils, as determined by GC-MS, is described. This is the first reported GC-MS study of the PMFs of these citrus species. While tangerine oil is as rich in polymethoxyflavones as orange oil, they are less abundant and occur at lower concentrations in grapefruit oil. Hydroxy-polymethoxyflavones were identified by GC-MS in tangerine oil. One hydroxy-pentamethoxyflavone, M+ = 388, identified in tangerine was also present at low levels in both orange and grapefruit oils. These results are compared with previous studies utilizing HPLC and GC.
Article
A radioimmunoassay (RIA) that can be used for the quantification of naringin in grapefruit tissues is described. The assay utilizes antisera raised against a naringin 4-O-(carboxymethyl)oxime hapten. The tracer used was a 3H derivative of naringin that was stable for at least 8-12 months. The detection limit of the assay is 0.2 ng or 2 ppb of naringin. Only flavanone 7-neohesperidosides are detected by the assay and naringin is the most reactive compound; the isomeric 7-rutinosides do not interfere. The RIA has a high sample throughput and requires only dilution of crude extracts. The reliability and reproducibility of the assay are demonstrated by intra- and interassay variability of 2.3% and 5.0% cv, respectively.
Article
An analysis of the limonin and naringin content of 6685 grapefruit juice samples (representing approximately 6% of all grapefruit harvested) collected from three Florida State Test Houses showed that there were statistically significant differences between the Test Houses. There also was a statistically significant difference in the concentration of these compounds in the juice from the different cultivars of fruit sampled. Average limonin and naringin concentrations in the juice remained fairly constant through the beginning of the season until a freeze occurred in early 1981. Juice obtained from fruit harvested after this freeze contained decreasing amounts of limonin and increasing amounts of naringin through the remainder of the season. Results showed that there was no strong correlative relationship between limonin, naringin, Brix, percent acid, and Brix/acid ratio.
Article
Narirutin, naringin, hesperidin, and neohesperidin concentrations in juices from 52 citrus cultivars were determined using HPLC. Neither naringin nor neohesperidin was detected in sweet orange (Citrus sinensis), tangerine (Citrus reticulata), tangerine-like hybrids, or most tangelos. Grapefruit (Citrus paradisi), sour orange (Citrus aurantium), and K-Early (a grapefruit-like tangelo) juices all contain similar amounts of naringin and widely varying amounts of neohesperidin. Therefore, naringin cannot be used as the sole indicator for the presence of grapefruit juice in orange juice. However, neohesperidin concentrations can be used to differentiate grapefruit, sour orange, and K-Early juices. Naringin concentrations in these cultivars ranged from 100 to 800, 150 to 350, and 150 to 200 ppm, respectively, whereas, neohesperidin concentrations ranged from 4 to 10, 100 to 200, and 600 to 950 ppm, respectively.
Article
Flavanone glycosides (FG) found in citrus juices have been sepd. and quant. detd. by reversed-phase liq. chromatog. (LC) using a C18 packed column and water-acetonitrile-tetrahydrofuran-glacial acetic acid eluent system. The influence of juice pH on hesperidin and narirutin detns., from com. orange juices, has been studied at different pH values (from 2.0 to 6.2). The response factors, avs., relative std. deviations, and recoveries of six FG were detd. using LC with an UV detector at 280 nm. The six FG and three unknown compds. found in citrus juices were detd. in 124 samples of lemons, limes, grapefruits, and sweet oranges. The major FG in each citrus group were as follows: in lemon and lime, eriocitrin (47-94 mg L-1) and hesperidin (84-196 mg L-1); in sweet orange, narirutin (30-84 mg L-1) and hesperidin (235-407 mg L-1); in grapefruit, narirutin (33-161 mg L-1) and naringin (113-481 mg L-1). Factorial discriminant anal. of the data obtained effectively differentiated lemon and lime and varieties of grapefruits (white, pink, red, and green) and sweet oranges (Valencia, navel, blood, Thomson, and Malta). [on SciFinder(R)]
Article
SUMMARYA recently developed chromatographic-fluorometric method was used for individual quantitative determination of naringin, neohesperidin, poncirin, naringeuin-7-β-rutinoside, hesperidin, and isosakuranetin-7-β-rutinoside in juice sacs of Texas Ruby Red grapefruit harvested in late July and late September, 1964, and monthly thereafter through late April, 1965. The concentrations of the six glycosides in these juice sacs were found to decrease rapidly and approximately porportionally during the period from late July through late November. In December–April, the concentrations of all six glycosides tended to decrease, although the monthly changes were slight. These results are compared with data obtained from the same samples by the Davis method for “naringin” determination and with taste-panel evaluations of grapefruit juice bitterness.
Article
Flavonoid glycosides in citrus were characterised by high-performance liquid chromatography using both ultraviolet and fluorescence detection. The effects of sample preparation on the chromatographic profiles are reported. Key variables in the profiles useful as chemotaxonomic markers were identified with the aid of pattern recognition, which was also used to create sample categories. LC–MS data are presented and the advantages of mass spectrometric detection are demonstrated. © 1997 SCI.
Article
The levels of the flavanones, neohesperidin and naringin, and the ratio in immature and mature fruit of different varieties of Citrus aurantium and the Citrus paradisi Macf. × Citrus depresssa Hayata hybrid are compared, and the flavonic content is analysed for the first time. Fruits of the hybrid, which are used to obtain neohesperidin for industrial-scale transformation into the intensely sweet neohesperidin dihycrochalcone, have two advantages: (1) although the levels of neohesperidin in the hybrid are similar to those detected in the immature fruit of Citrus aurantium, the levels of naringin detected in the immature fruit of the hybrid are lower, which means that the ratio is greater and the need for costly neohesperidin purification processes correspondingly less; (2) unlike the mature fruit of Citrus aurantium, the mature fruits of the hybrid accumulate high levels of neohesperidin with a high ratio, so that these too can be used to obtain neohesperidin.
Article
Clarified, debittered grapefruit juice concentrate (64.2 °Bx) was produced by membrane filtration, debittering, and an evaporation process. Debittering by an XAD-16 adsorption column removed more than 78% of bitterness in grapefruit juice, based on naringin content. Also, some of the non-bitter flavonoids, such as narirutin and hesperidin, were nearly completely removed. Other values, such as vitamin C, and total phenolics, based on absorbance at 325 nm, were also reduced (P<0.05) after debittering. The vitamin C loss can probably be attributed to juice handling during processing. Absorption spectra in the 200–450 nm region showed characteristic absorption maxima around 280 and 322 nm in the control but no spectral fine structure in debittered concentrate. Besides differences in flavonoid profile, there was a slight difference in colour. Debittered concentrate had less chroma (CIE C*) and more lightness (CIE L*) than the control. Thus, the colour of debittered concentrate could be described as slightly paler than that of the control.
Article
The USDA Special Interest Database for flavonoid content of selected foods contains 26 most abundant compounds within 5 predominant subclasses of flavonoids–flavonols, flavones, flavanones, flavan-3-ols, and anthocyanidins. All the data were evaluated for 5 quality evaluation categories (sampling plan, sample handling, analytical method, analytical quality control and number of samples), using the data quality evaluation system developed by the USDA scientists. Confidence Codes (A–through D) were then assigned to every value. The database contains acceptable values for 225 selected foods. Only 97 sources out of approximately 475 collected included acceptable analytical data. The overall quality of data was good with 64% of the observations receiving A or B confidence codes; the flavan-3-ols subclass received better ratings than other subclasses. While this is the first comprehensive database for flavonoids in foods, the majority of data came from Europe and countries other than the US. Due to the observed variability in the values it will be important to have data for US foods. The evaluation of data quality helps set priorities and further identifies the foods to be analyzed as well as areas to improve data quality. Furthermore, release of data quality confidence codes with data provides necessary information to investigators to assess the impact of flavonoid intake on risk of various chronic diseases.
Article
Citrus flavonoids have been shown to possess biological activities such as anti-inflammatory properties, cholesterol lowering and immune system modulation. In this study, 12 made-from-concentrate (MFC) and 14 not-from-concentrate (NFC) orange juices, and five NFC grapefruit juices available in the US market were analyzed for their flavonoid content by reverse phase HPLC. Individual and total flavonoid content was determined for all of the brands. The correlation between flavonoid content (mg) and price (US dollar) per unit volume of orange and grapefruit juices were also evaluated. Significant differences (P⩽0.05) among the brands and within the brand were observed for all of the prominent flavanone glucosides. Within the brand, juice types containing added antioxidant vitamins C and E were not superior in flavonoid content compared to orange juice types devoid of added antioxidant vitamins. Total flavonoid content of MFC orange juices (53 mg/100 mL; n=12) was significantly (P⩽0.05) higher than NFC orange juices (36.5 mg/100 mL; n=14). Hesperidin was found to be the major flavonoid followed by narirutin and didymin in orange juice. Naringin, narirutin, and poncirin were the major flavonoids in all brands of grapefruit juices. The concentration of didymin was considerably higher in NFC orange juices compared to MFC orange juices. Interestingly, no correlation was observed between price and the total flavonoid content of MFC orange juices and NFC grapefruit juices. However, a significant negative correlation (r=-0.49; P=0.001) was observed for NFC orange juices. This study provides valuable information on flavonoid composition of orange and grapefruit juices commonly available in the US market.
Article
A review has been presented of the biochemistry and pharmacology of a class of natural products, the flavonoids. These substances which are widely distributed in the plant kingdom and present in considerable quantities in common food products, spices and beverages have in a concentrated form (Propolis) been used since ancient times by physicians and laymen to treat a great variety of human diseases but they have yet to pass the tests of modern, controlled, clinical experimentation. An attempt has been made to present the fundamental evidence from the basic biological sciences which is required to stimulate the interest of the clinicians in this new field. The few existing reports on the careful pharmacodynamic, pharmacokinetic and clinical studies which have been made have been summarized to provide a basis for a full-scale investigation of the therapeutic potential of flavonoids.
Article
Flavonoids are non-nutritive compounds of plants that have been intensively investigated during the past years due to their possible protective effects against chronic diseases. In vitro studies were able to demonstrate for flavonols, flavones, and most recently also for anthocyanins a considerable antioxidative activity, mainly based on scavenging of oxygen radicals. Flavonols and anthocyanins are commonly found in European fruits and vegetables. In addition, black tea and red wine may have a high content of these compounds. Those food items are the main sources of flavonol consumption each contributing to a different degree to the overall intake. The absorption of aglycones has been established before. However, only recently could the absorption of flavonolglycosides be demonstrated. The mean intake of flavonols of the German population was calculated using data from the National German Food Consumption Survey. According to this analysis, the daily per capita intake was about 11.5 mg flavonols, mainly derived from fruits and vegetables, but also from black tea and red wine. Epidemiological studies have been directed to investigate the association between flavonol consumption and diseae risk. An inverse association between flavonol intake and mortality from myocardial infarction was observed. According to one of three studies, the flavonoid intake can be inversely correlated with cancer risk. This review summarizes the current knowledge on the occurrence, intake, bioavailability, and antioxidative properties of flavonols, flavones, and anthocyanins as well as the associations between flavonol intake and disease risks. Possible health related effects especially of flavonols are critically reflected, and the necessity of further research in outlined.
Article
The effects of the citrus bioflavonoid naringin were tested by using it as a supplement in a high-cholesterol diet. Male rats were fed for 42 days with a 1% (wt/wt) high cholesterol diet either with or without naringin-supplementation (0.1%, wt/wt) to study the effect on plasma lipid levels, hepatic lipid contents, hepatic enzyme activity, and the excretion of fecal neutral sterols. Naringin did not significantly alter the levels of plasma triglycerides, however, the levels of plasma cholesterol (3.80 +/- 0.31 mmol/L vs. 2.61 +/- 0.30 mmol/L, mean +/- SE; p < 0.05) and hepatic cholesterol (70.3 +/- 4.3 mg/g vs. 54.3 +/- 3.8 mg/g, mean +/- SD; p < 0.05) were significantly lowered compared to those of the control. HMG-CoA reductase (2487.0 +/- 210.0 pmole/min/mg vs. 1879.0 +/- 236.0 pmole/min/mg, mean +/- SE; p < 0.05) and ACAT (806.0 +/- 105.0 pmole/min/mg vs. 643.0 +/- 80.0 pmole/min/mg, mean +/- SE; p < 0.05) activities were both substantially lower in the naringin-supplemented group than in the control. The naringin supplementation markedly decreased the excretion of fecal neutral sterols (204.7 +/- 28.5 mg/day) compared to the control (521.9 +/- 53.9 mg/day). The combination of the inhibited HMG-CoA reductase (-24.4%) and ACAT (-20.2%) activities as a result of naringin supplementation could account for the decrease of fecal neutral sterols.
Article
Nine commercial brands of grapefruit juice were analyzed for their flavonoid content by HPLC to determine if significant brand-to-brand variance in grapefruit juice flavonoid content exists. Flavonoid glycosides narirutin, naringin, hesperidin, neohesperidin, didymin, and poncirin have been identified in all the grapefruit juices examined. The aglycone quercetin was detected in only two brands. All the juices were free from methoxylated flavonoid aglycones. There was a significant difference in the amounts of total flavonoids and individual flavonoids in the nine brands. The concentration of total flavonoids ranged between 19.44 and 84.28 mg/100 ml juice. Naringin was found to be the major flavonoid followed by narirutin and hesperidin. Their concentrations ranged from 14.56 to 63.8; 2.25 to 12.20; and 0.24 to 3.12 mg/100 ml juice, respectively.
Article
The flavonoids, naringin and naringenin and the furanocoumarin, bergapten (5-methoxypsoralen), were detected in some fresh grapefruit and commercial grapefruit juices but were not detected in other fruit juices tested (orange; orange with apple base; dark grape; orange and mango with apple base; orange, peach, passion fruit juice). The contents of these three grapefruit constituents in commercial juice and fresh grapefruit varied from brand to brand and also from lot to lot. Juice was prepared from the fresh fruit via different methods (by hand, squeezer or blender). The naringin content, after hand-squeeze, ranged from 115 to 384 mg/l. With hand-squeeze juice production, bergapten was not detected (less than 0.5 mg/l) in two varieties of grapefruit, and naringenin was usually not in detectable levels (less than 2 mg/l) in three varieties. All three constituents were present in New Zealand grapefruit preparations (including juice by hand-squeeze) and different lots showed variation in content (1.5-, 2.3- and 4.7-fold for naringin, naringenin and bergapten, respectively). Differences in the concentrations of these three constituents, which have potential for drug interaction, may contribute to the variability in pharmacokinetics of CYP3A4 drugs and some contradictory results of drug interaction studies with grapefruit juice.
Article
The protein phosphatase-inhibitory algal toxins, okadaic acid and microcystin-LR, induced overphosphorylation of keratin and disruption of the keratin cytoskeleton in freshly isolated rat hepatocytes. In hepatocyte cultures, the toxins elicited DNA fragmentation and apoptotic cell death within 24 h. All these toxin effects could be prevented by the grapefruit flavonoid, naringin. The cytoprotective effect of naringin was apparently limited to normal hepatocytes, since the toxin-induced apoptosis of hepatoma cells, rat or human, was not prevented by the flavonoid.
Article
Naringin, a bioflavonoid found in citrus fruit peel, is known to have an antioxidative effect, but its effect on atherosclerosis has not been studied. This study evaluated the effect of naringin on blood lipid levels and aortic fatty streaks, and its action mechanism in hypercholesterolemic rabbits. Male New Zealand white rabbits were fed a 0.25% cholesterol diet and divided into an untreated group (n = 4), a naringin-treated group (n = 5; 500 mg/kg per day), and a lovastatin-treated group (n = 5; 20 mg/kg per day). After 8 weeks, blood was sampled and analyzed biochemically. Aorta and liver were harvested and examined histologically. Cholesterol level in rabbits fed the 0.25% cholesterol diet reached 17 times normal and decreased in the rabbits fed naringin and lovastatin, whose effects were not statistically significant (p > 0.05). However, both naringin and lovastatin effectively decreased the area of fatty streak in thoracic aorta on macroscopic analysis (p < 0.05) and significantly reduced subintimal foam cell infiltration on microscopic morphometry (p < 0.05). These foam cells were macrophages on immunohistochemical analysis. Naringin treatment inhibited hypercholesterolemia-induced intercellular adhesion molecule-1 (ICAM-1) expression on endothelial cells. Hypercholesterolemia caused fatty liver and elevation of liver enzymes, which was prevented by naringin but not by lovastatin. Naringin significantly reduced fatty streak formation and neointimal macrophage infiltration and also inhibited the expression of ICAM-1 in endothelial cells, suggesting that suppression of ICAM-1 contributed to the antiatherogenic effect. Naringin, unlike lovastatin, has a hepatoprotective action.
Article
The consumption of a cholesterol-enriched diet increases the degree of lipid peroxidation, which is one of the early processes of atherosclerosis. The aim of this trial was to determine the antioxidative effects of the citrus bioflavonoid, naringin, a potent cholesterol-lowering agent, compared to the cholesterol-lowering drug, lovastatin, in rabbits fed a high cholesterol diet. Male rabbits were served a high-cholesterol (0.5%, w/w) diet or high-cholesterol diet supplemented with either naringin (0.5% cholesterol, 0.05% naringin, w/w) or lovastatin (0.5% cholesterol, 0.03% lovastatin, w/w) for 8 weeks to determine the plasma and hepatic lipid peroxide, plasma vitamin A and E levels, and hepatic hydrogen peroxide levels, along with the hepatic antioxidant enzyme activities and gene expressions. Only the lovastatin group showed significantly lower plasma and hepatic lipid peroxide levels compared to the control group. The naringin supplementation significantly increased the activities of both hepatic SOD and catalase by 33% and 20%, respectively, whereas the lovastatin supplementation only increased the catalase activity by 23% compared to control group. There was no difference in the GSH-Px activities between the various groups. Content of H2O2 in hepatic mitochondria was significantly lower in groups supplemented with lovastatin and naringin than in control group. However, there was no difference in cytosolic H2O2 content in liver between groups. The concentration of plasma vitamin E was significantly increased by the naringin supplementation. When comparing the antioxidant enzyme gene expression, the mRNA expression of SOD, catalase and GSH-Px was significantly up-regulated in the naringin-supplemented group. Accordingly, these results would appear to indicate that naringin, a citrus bioflavonoid, plays an important role in regulating antioxidative capacities by increasing the SOD and catalase activities, up-regulating the gene expressions of SOD, catalase, and GSH-Px, and protecting the plasma vitamin E. In contrast, lovastatin exhibited an inhibitory effect on the plasma and hepatic lipid peroxidation and increased the hepatic catalase activity in high-cholesterol fed rabbits.
Article
Flavonoids are pigments fenolics of plants that possess several biological activities, and many of these are associated with prevention of chronic diseases as cancer and hyperlipidemia. This work had as objective evaluates the effect of the flavonoids naringin and rutin on the metabolism lipidic of chicks hypercholesterolemic. In agreement with the results it can be observed that naringin and rutin reduced the levels of total cholesterol significantly, cholesterol-LDL, cholesterol-VLDL and triglycerols, not presenting, however, reductions in the levels of cholesterol-HDL.
Article
Due to the strong evidence on the involvement of active oxygen species in a variety of disorders, the role of antioxidants against oxidative stress has recently received increased attention. Twenty male rabbits were served a high-cholesterol (HC, 5 g/kg diet) diet or high-cholesterol diet supplemented with naringin (0.5 g/kg diet) or probucol (0.5 g/kg diet) for 8 weeks to compare the antioxidative effects of the citrus bioflavonoid (naringin) and antioxidative cholesterol-lowering drug (probucol). The plasma thiobarbituric acid-reactive substances (TBARS) concentration was not significantly different between the groups, whereas the hepatic TBARS concentration was significantly lower in the probucol group than in both normal and HC control or naringin group. Probucol and naringin supplementation led to an increase in the hepatic superoxide dismutase (SOD) and catalase (CAT) activities, and a decrease in the hepatic mitochondrial hydrogen peroxide (H(2)O(2)) content compared to the HC-control group. However, there was no difference in the cytosolic H(2)O(2) content or cytosolic glutathion peroxidase (GSH-Px) activity in the liver between the groups. Both naringin and probucol supplements significantly increased the plasma vitamin E concentration compared to the HC-control group. As regards the antioxidant enzyme gene expressions, naringin significantly increased the expression of three antioxidant enzyme mRNAs compared to the HC-control group, whereas probucol significantly increased the only SOD mRNA expression. The probucol supplement was very potent in the antioxidative defense system, whereas naringin exhibited a comparable antioxidant capacity based on increasing the gene expressions in the antioxidant enzymes, while also increasing the hepatic SOD and CAT activities, sparing plasma vitamin E, and decreasing the hepatic mitochondrial H(2)O(2) content.
Article
Oxidative stress is implicated in the initiation of maturity onset cataract. Quercetin, a major flavonol in the diet, inhibits lens opacification in a lens organ culture oxidative model of cataract. The aim of this research was to investigate the metabolism of quercetin in the lens and show how its metabolism affects the ability to prevent oxidation-induced opacity. The LOCH model (Free Radical Biology & Medicine 26:639; 1999) was employed, using rat lenses to investigate the effects of quercetin and metabolites on hydrogen peroxide-induced opacification. High-performance liquid chromatography analysis showed that the intact rat lens is capable of converting quercetin aglycone to 3'-O-methyl quercetin (isorhamnetin). Over a 6 h culture period no further metabolism of the 3'-O-methyl quercetin occurred. Loss of quercetin in the lens was accounted for by the increase in 3'-O-methyl quercetin. Incubation with 3,5-dinitrocatechol (10 microM), a catechol-O-methyltransferase (COMT) inhibitor, prevented the conversion of quercetin to 3'-O-methyl quercetin. The presence of both membrane-bound and soluble COMT was confirmed by immunoblotting. The results demonstrate that in the rat lens COMT methylates quercetin and that the product accumulates within the lens. Quercetin (10 microM) and 3'-O-methyl quercetin (10 microM) both inhibited hydrogen peroxide- (500 microM) induced sodium and calcium influx and lens opacification. Incubation of lenses with quercetin in the presence of COMT inhibitor revealed that the efficacy of quercetin is not dependent on its metabolism to 3'-O-methyl quercetin. The results indicate dietary quercetin and metabolites are active in inhibiting oxidative damage in the lens and thus could play a role in prevention of cataract formation.
Article
The effect of various doses, viz. 0, 0.5, 1, 2, 4, 6 and 8 mg/kg body weight of naringin (NIN) (a citrus flavanone) was studied on the alteration in the radiation-induced micronucleated polychromatic (MPCE) and normochromatic (MNCE) erythrocytes in mouse bone marrow exposed to 2 Gy of 60Co gamma-radiation. The treatment of mice with various doses of NIN before exposure to 2 Gy resulted in a significant decline in the frequency of MPCE when compared to the non-drug-treated irradiated control. However, the greatest reduction in MPCE was observed for 2mg/kg body weight NIN, accompanied by a highest PCE/NCE ratio when compared with the non-drug-treated irradiated control. Therefore, further studies were carried out using this dose of NIN, where the animals were administered with 2mg/kg body weight of NIN before exposure to 0, 0.5, 1, 2, 3 and 4 Gy of gamma-radiation. The frequency of MPCE and MNCE increased in a dose-dependent manner in both the non-drug-treated irradiated control and NIN-pretreated irradiated groups up to a dose of 2 Gy, while a further increase in the irradiation dose resulted in a significant decline in MPCE and MNCE frequencies in both groups. Pretreatment of mice with 2mg/kg body weight of NIN resulted in a significant decline in the frequencies of MPCE and MNCE. NIN treatment not only reduced the frequency of MPCE with one micronucleus, but also of MPCE with multiple micronuclei (MN), indicating its ability to reduce complex chromosome aberrations. Conversely, the PCE/NCE ratio declined in a dose-dependent manner in both groups. The treatment of mice with NIN before exposure to different doses of gamma-radiation resulted in the inhibition in this decline in the PCE/NCE ratio. Our study demonstrates that NIN is able to protect mouse bone marrow cells against the radiation-induced DNA damage and decline in the cell proliferation as observed by a reduction in the micronucleus frequency and an increase in PCE/NCE ratio, respectively, in the NIN-pretreated irradiated group.
Article
Citrus fruits contain high concentrations of several classes of phenols, including numerous hydroxycinnamates, flavonoid glycosides, and polymethoxylated flavones. The latter group of compounds occurs without glycosidic linkages and has been shown to inhibit the proliferation of a number of cancer cell lines. This antiproliferative property was further demonstrated against additional human cancer cell lines, and the antiproliferative actions of a series of synthetic methoxylated flavones were also studied. Similar to the naturally occurring compounds, the synthetic compounds exhibited strong antiproliferative activities. In many cases the IC(50) values occurred below 10 microm. Other hydroxylated flavone and flavanone aglycons also exhibited antiproliferative activities against the cancer cell lines, with the flavones showing greater activities than the flavanones. Glycosylation of these compounds removed their activity. The strong antiproliferative activities of the polymethoxylated flavones suggest that they may have use as anticancer agents in humans.
Article
The current study was performed to investigate the effect of naringin supplements on the alcohol, lipid, and antioxidant metabolism in ethanol-treated rats. Male Sprague-Dawley rats were randomly divided into six groups (n = 10) based on six dietary categories: ethanol and naringin-free, ethanol (50 g/L) plus low-naringin (0.05 g/L), ethanol plus high-naringin (0.125 g/L), and three corresponding pair-fed groups. The pair-fed control rats received an isocaloric diet containing dextrin-maltose instead of ethanol for 5 wks. Among the ethanol treated groups, the naringin supplements significantly lowered the plasma ethanol concentration with a simultaneous increase in the ADH and/or ALDH activities. However, among the ethanol-treated groups, naringin supplementation resulted in a significant decrease in the hepatic triglycerides and plasma and hepatic total cholesterol compared to that in the naringin-free group. Naringin supplementation significantly increased the HDL-cholesterol and HDL-C/total-C ratio, while lowering the AI value among the ethanol-treated groups. Hepatic lipid accumulation was also significantly reduced in the naringin-supplemented groups compared to the naringin-free group among the ethanol-treated groups, while no differences were found among the pair-fed groups. Among the ethanol-treated groups, the low-naringin supplementation resulted in a significant decrease in the levels of plasma and hepatic TBARS, whereas it resulted in higher SOD and GSH-Px activities and gluthathion levels in the liver. Accordingly, naringin would appear to contribute to alleviating the adverse effect of ethanol ingestion by enhancing the ethanol and lipid metabolism as well as the hepatic antioxidant defense system.
Article
In vitro studies have demonstrated increased atherogenicity of oxidized low-density lipoprotein (ox-LDL) compared to native LDL. Oxidative modification of LDL alters its structure allowing LDL to be taken up by scavenger receptors on macrophage, endothelial, and smooth muscle cells, leading to the formation of lipid-laden foam cells, the hallmark of early atherosclerotic lesions. The susceptibility of LDL to in vitro oxidation was assessed essentially by the technique described by Esterbauer et al. LDL oxidation were monitored by change in 234-absorbance in the presence and absence of pure flavonoids. Morin, genistein, apigenin and biochanin A, naringin and quercetin were used at different concentration. These flavonoids significantly inhibit in vitro LDL oxidation, genistein, morin and naringin have stronger inhibitory activity against LDL oxidation than biochanin A or apigenin. This study show that flavonoids prevent in vitro LDL oxidation and probably would be important to prevent atherosclerosis.
Article
The natural product quercetin is a flavonoid found in many fruits and vegetables. Previous research has shown that quercetin has antitumor, anti-inflammatory, antiallergic, and antiviral activities. In the present investigation we studied the effect of quercetin on the ability of prostate cancer cell lines with various degrees of aggressive potential to form colonies in vitro. Specifically, we examined the molecular mechanisms underlying this effect, including the expression of cell cycle and tumor suppressor genes as well as oncogenes. We observed that quercetin at concentrations of 25 and 50 micro M significantly inhibited the growth of the highly aggressive PC-3 prostate cancer cell line and the moderately aggressive DU-145 prostate cancer cell line, whereas it did not affect colony formation by the poorly aggressive LNCaP prostate cancer cell line or the normal fibroblast cell line BG-9. Using the gene array methodology, we found that quercetin significantly inhibited the expression of specific oncogenes and genes controlling G(1), S, G(2), and M phases of the cell cycle. Moreover, quercetin reciprocally up-regulated the expression of several tumor suppressor genes. In conclusion, our results demonstrate that the antitumor effects of quercetin directly correlate with the aggressive potential of prostate cancer cells and that the mechanism(s) of quercetin-mediated antitumor effects may involve up-regulation of tumor suppressor genes and reciprocal down-regulation of oncogenes and cell cycle genes. The results of these studies provide a scientific basis for the potential use of flavonoids as nutraceuticals in the chemoprevention of cancer.
Article
Epidemiological studies have consistently shown that regular consumption of fruits and vegetables is strongly associated with reduced risk of developing chronic diseases, such as cancer and cardiovascular disease. It is now widely believed that the actions of the antioxidant nutrients alone do not explain the observed health benefits of diets rich in fruits and vegetables, because taken alone, the individual antioxidants studied in clinical trials do not appear to have consistent preventive effects. Work performed by our group and others has shown that fruits and vegetable phytochemical extracts exhibit strong antioxidant and antiproliferative activities and that the major part of total antioxidant activity is from the combination of phytochemicals. We proposed that the additive and synergistic effects of phytochemicals in fruits and vegetables are responsible for these potent antioxidant and anticancer activities and that the benefit of a diet rich in fruits and vegetables is attributed to the complex mixture of phytochemicals present in whole foods. This explains why no single antioxidant can replace the combination of natural phytochemicals in fruits and vegetables to achieve the health benefits. The evidence suggests that antioxidants or bioactive compounds are best acquired through whole-food consumption, not from expensive dietary supplements. We believe that a recommendation that consumers eat 5 to 10 servings of a wide variety of fruits and vegetables daily is an appropriate strategy for significantly reducing the risk of chronic diseases and to meet their nutrient requirements for optimum health.
Article
Polyphenols are the most abundant dietary antioxidants and research on their role in the prevention of degenerative diseases has developed quickly over these last few years. This paper reviews the recent studies on the prevention of cardiovascular diseases by polyphenols, focusing on human studies. A large number of recent intervention studies have shown that several biomarkers of cardiovascular risk are influenced by the consumption of polyphenol-rich foods. Effects on biomarkers of oxidative stress, lipemia and inflammation appear so far inconclusive. More consistent effects have been observed on endothelial function and haemostasis and support a reduction of risk by polyphenols in agreement with the few epidemiological studies already published. All clinical studies have used foods or beverages containing a mixture of different polyphenols and the exact nature of the most active compounds remains largely unknown. Absorption, metabolism and elimination vary widely between polyphenols. These data on bioavailability should be taken into account to improve the experimental design and the interpretation of the observed effects. Future intervention studies should include a detailed assessment of the bioavailability of polyphenols. Beyond clinical trials carried out with polyphenol-rich foods, more studies with pure polyphenols will also be needed to establish their role in the prevention of cardiovascular diseases.
Article
As part of a systematic study of the effects of phytochemicals beyond antioxidation on cancer prevention, we investigated whether naringenin (NR), a citrus flavonoid, stimulates DNA repair following oxidative damage in LNCaP human prostate cancer cells. The 8-hydroxydeoxyguanosine (8-OH-dG) to deoxyguanosine (dG) ratio was measured after cells were treated with 200 micromol/L of ferrous sulfate in serum-free medium followed by NR exposure for 24 h in growth medium. The results demonstrated that exposure to 10-80 micromol/L of NR led to a significant decrease in the ratio of 8-OH-dG to 10(6) dG. Because cells were treated with NR after ferrous sulfate was removed, we conclude that we demonstrated an effect on DNA repair beyond antioxidation. In support of this conclusion, we determined the induction of mRNA expression over time after oxidative stress followed by NR administration of three major enzymes in the DNA base excision repair (BER) pathway: 8-oxoguanine-DNA glycosylase 1 (hOGG1), apurinic/apyrimidinic endonuclease and DNA polymerase beta (DNA poly beta). hOGG1 and DNA poly beta mRNA expression in cells after 24-h exposure to NR was increased significantly compared with control cells without NR. The intracellular concentration of NR after exposure to 80 micromol/L was 3 pmol/mg protein, which is physiologically achievable in tissues. In conclusion, the cancer-preventive effects of citrus fruits demonstrated in epidemiological studies may be due in part to stimulation of DNA repair by NR, which by stimulating BER processes may prevent mutagenic changes in prostate cancer cells.
Article
Flavonoids are a large class of naturally occurring aromatic secondary plant metabolites. They constitute one of the most characteristic classes found in nature and more than 4000 flavonoids have been identified and divided into several subclasses. Flavonoids have several effects on human health, mainly related to their antioxidant activity. As a result of the increased interest in the biologically active compounds in food, many research studies have investigated the detection and quantification of antioxidants. Citrus plants are of great interest since they accumulate large amounts of flavonoids and fruit and juices of these species are consumed in large quantities. Despite the extensive research performed on Citrus flavonoids, many compounds still remain unidentified. In this work, flavonoids of five citrus juices: lemon, grapefruit, bergamot, orange, and mandarin were analyzed by microHPLC coupled on-line with an MS detector equipped with an ESI source operating in negative mode. The use of microcolumn HPLC greatly enhanced detection performance. In total, 20 flavonoids of two different subclasses (flavanone and flavone glycosides) were identified with the help of retention data and MS spectral information.
Article
Epidemiological studies have suggested that a high consumption of apples may protect against asthma and chronic obstructive pulmonary disease. This effect has been attributed to their high flavonoid content, but few studies have investigated the relationship between flavonoid intake and obstructive lung disease directly. In a population-based, case-control study of 1,471 adults aged 16–50 yrs in London (UK), the present study examined whether dietary intake of catechins, flavonols and flavones was negatively associated with asthma, asthma severity and chronic sputum production. Asthma was defined by positive responses to a standard screening questionnaire in 1996 and information about usual diet was obtained by a food frequency questionnaire in 1997. After controlling for potential confounders, dietary intake of these three flavonoid subclasses was not significantly associated with asthma, (odds ratio per quintile (95% confidence interval) = 0.94 (0.86–1.02); 1.00 (0.92–1.09); 0.98 (0.88 –1.08) for flavones, flavonols and total catechins, respectively) nor was it associated with asthma severity, or chronic sputum production. In conclusion, no evidence was found for a protective effect of three major subclasses of dietary flavonoids on asthma. It is possible that other flavonoids or polyphenols present in apples may explain the protective effect of apples on obstructive lung disease.
Article
Grapefruit juice (GFJ) has been found to interact with several medications, increasing their oral bioavailability and the risk of toxicity. Inhibition of CYP3A4 in the small intestine by flavonoids (such as naringin and naringenin) and furanocoumarins (including bergamottin and 6',7'-dihydroxybergamottin) present in GFJ seems to be the predominant mechanism, although P-glycoprotein and influx transporters in the small intestine are also involved. The quantity of interactive compounds ingested may affect the magnitude and mechanism of the food-drug interaction. Therefore, these four compounds were quantified by HPLC analysis in commercially available and fresh-squeezed GFJ and in grapefruit tissues. Considerable variability in naringin (174-1492 micromol/L), bergamottin (1.0-36.6 micromol/L), and 6',7'-dihydroxybergamottin (0.22-52.5 micromol/L) was observed, whereas naringenin could not be detected. White grapefruit showed higher concentrations of naringin and furanocoumarins located in the albedo and flavedo compared with red varieties. Findings from this study suggest considering concentrations of components with a potential for drug interactions in GFJ-drug interaction studies. The concentration of potentially contributing compounds may crucially influence the magnitude of observed interaction and impair direct comparison of studies in which different juices have been used.
Article
Increasing data from epidemiological and in vitro studies show that the isoflavonoids, genistein and daidzein, and the flavonols, quercetin and kaempferol, are protective against postmenopausal bone loss. However, the physiological mechanisms for these effects are not well understood. We now report that kaempferol exerts profound antiosteoclastogenic effects by acting on both osteoblasts and osteoclasts. Kaempferol but not quercetin dose-dependently inhibited tumor necrosis factor α (TNFα)-induced production of the osteoclastogenic cytokines interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1/CCL2) in osteoblasts. The effect on IL-6 was posttranscriptional, whereas kaempferol reduced MCP-1 mRNA levels. In addition, in mouse primary calvarial osteoblasts, kaempferol but not quercetin blocked TNFα-induced translocation of the nuclear factor κB (NF-κB) subunit p65 from the cytoplasm to the nucleus. However, TNFα-stimulated intracellular ROS production was unaltered by kaempferol. In RAW264.7 cells, a monocyte/macrophage precursor for osteoclasts, both kaempferol and quercetin dose-dependently inhibited the receptor activator of NF-κB ligand (RANKL)-induced immediate-early oncogene c-fos expression at 6 h. After 3-5 days, both flavonols robustly inhibited RANKL-induced expression of the osteoclastic differentiation markers, RANK and calcitonin receptor. Consistent with down regulation of these osteoclastic differentiation markers, both flavonols strongly attenuated the RANKL-induced formation of multinucleated osteoclasts. However, kaempferol was more potent than quercetin in inhibiting RANKL-stimulated effects on RAW264.7 cells. Thus, our data indicate that kaempferol exerts profound antiosteoclastogenic effects by specifically antagonizing TNF receptor family action on bone cells at two distinct levels, by disrupting production of osteoclastogenic cytokines from osteoblasts and attenuating osteoclast precursor cell differentiation.
Article
Statin, a HMG-CoA reductase inhibitor, was shown to increase BMP-2 gene expression for bone formation, by blocking the mevalonate pathway in cholesterol production. We investigated the effect of naringin, a flavonoid available commonly in citrus fruits, which was also a HMG-CoA reductase inhibitor, in UMR 106 osteoblastic cell line in vitro. The control group consisted of cells cultured without any intervention for different time intervals (24 h, 48 h, and 72 h), whereas the experimental (naringin) group consisted of cells cultured with naringin of different concentrations (0.001 micromol/L, 0.01 micromol/L, and 0.1 micromol/L) for the same time intervals of the control. Colorimetric Tetrazolium (MTT) assay, total protein content assay, and alkaline phosphatase activity were used to measure the cellular activities. Results for the naringin group showed an increase in MTT assay compared with the control and the effect was dose dependent. At high concentration (0.1 micromol), the increases ranged from 60% to 80%. In the total protein content assay, naringin also showed an increase compared with control and the effect was also dose dependent. At high concentration (0.1 micromol), the increases ranged from 9% to 20%. In the alkaline phosphatase activity assay, naringin at high concentration (0.1 micromol) significantly increased the activity up to 20%. In conclusion, naringin significantly increased bone cell activities in vitro. This is the first study specifically attempted to investigate the effect of naringin on bone cell activities. Besides statin, this provided another example of mevalonate pathway blockage in the cholesterol production pathway by HMG-CoA reductase inhibition will increase the bone cell activities.
Article
We have previously shown that 300 kcal from glucose intake induces a significant increase in reactive oxygen species (ROS) generation and nuclear factor-kappaB (NF-kappaB) binding in the circulating mononuclear cells in healthy normal subjects. We hypothesized that the intake of 300 calories as orange juice or fructose, the other major carbohydrate in orange juice, would induce a significantly smaller response than that of glucose. Four groups (eight subjects each) of normal-weight subjects were given a 300-cal drink of glucose (75 g), fructose (75 g), or orange juice or water sweetened with saccharin (control group) to drink, and then blood samples were collected. There was a significant increase in ROS generation by mononuclear cells (by 130 +/- 18%, P < 0.001), polymorph nuclear cells (by 95 +/- 22%, P < 0.01), and in NF-kappaB binding in mononuclear cells by 82 +/- 16% (P < 0.01) over the baseline after 2 h of glucose intake. These changes were absent following fructose, orange juice, or water intake. There was significantly lower ROS generation and NF-kappaB binding following orange juice, fructose, and water compared with glucose (P < 0.001 for all). Furthermore, incubation of mononuclear cells in vitro with 50 mmol/l of the flavonoids hesperetin or naringenin reduced ROS generation by 52 +/- 7% and 77 +/- 8% (P < 0.01), respectively, while fructose or ascorbic acid did not cause any change. Caloric intake in the form of orange juice or fructose does not induce either oxidative or inflammatory stress, possibly due to its flavonoids content and might, therefore, represent a potentially safe energy source.
Article
The 2005 Dietary Guidelines for Americans recommend that consumers choose a variety of nutrient-dense foods. Nutrient density is usually defined as the quantity of nutrients per calorie. Food and nutrition professionals should be aware of the concept of nutrient density, how it might be quantified, and its potential application in food labeling and dietary guidance. This article presents the concept of a nutrient density score and compares nutrient density scores for various 100% fruit juices. One hundred percent fruit juices are popular beverages in the United States, and although they can provide concentrated sources of a variety of nutrients, they can differ considerably in their nutrient profiles. Six methodologies were used to quantify nutrient density and 7 100% fruit juices were included in the analysis: apple, grape, pink grapefruit, white grapefruit, orange, pineapple, and prune. Food composition data were obtained from the USDA National Nutrient Database for Standard Reference, Release 18. Application of the methods resulted in nutrient density scores with a range of values and magnitudes. The relative scores indicated that citrus juices, particularly pink grapefruit and orange juice, were more nutrient dense compared to the other nonfortified 100% juices included in the analysis. Although the methods differed, the relative ranking of the juices based on nutrient density score was similar for each method. Issues to be addressed regarding the development and application of a nutrient density score include those related to food fortification, nutrient bioavailability, and consumer education and behavior.