Source Of Flavonols Research Articles

Profile of Phenolic Compounds of Prunus armeniaca L. Leaf Extract Determined by LC-ESI-QTOF-MS/MS and Their Antioxidant, Anti-Diabetic, Anti-Cholinesterase, and Anti-Inflammatory Potency.

In view of the limited information available in the literature concerning leaves as by-products of Prunus armeniaca cultivation, the aim of this work was to identify and characterize their principal polyphenolic constituents by LC-ESI-QTOF-MS/MS and screening in vitro biological potency as antioxidant capacity (ABTS, online ABTS, FRAP, ORAC), antidiabetic (α-amylase, α-glucosidase), anti-obesity (pancreatic lipase), anti-cholinesterase (AChE and BChE), and anti-inflammatory (COX-1 and COX-2) inhibitory activity. Comparison of different polyphenolic extracts of P. armeniaca cultivar leaves according to their quantitative composition revealed them to be exceptional sources of hydroxycinnamic acids, and to a lesser extent as sources of flavonols. Polyphenol-rich apricot leaf extract (PrALe) showed the most effective anti-obesity action through inhibition of pancreatic lipase, COX-1 and antioxidant capacity, especially the oxygen radical absorbance capacity, which was particularly correlated with polyphenolic compounds. Online ABTS radical UPLC-PDA-PDA analysis clearly demonstrated that the three predominant compounds of PrALe are quercetin-3-O-rutinoside > 5-O- and 3-O-caffeoylquinic acid, which basically contribute to antioxidant potential. These results assist in the evaluation of plant sources of potential new raw materials for application in different commercial sectors, especially for food, cosmetics and pharmaceuticals production.

About the content of flavonols in leaves of some species of Spiraea in the North (Republic of Komi)

For the first time the content of flavonols in the leaves of Spiraea plants introduced in the Botanical garden and in the leaves of one sample of the wild species Spiraea media in the North (Komi Republic) was determined. The total content of flavonols among the species of Spirea varies from 1.8% to 5.7%. The widespread Eurasian species of Spiraea media has high flavonols content - from 4.8 to 5.1% in the introduced sample and lower in the local sample - 3.5%. Spiraea species can be a raw source of flavonols.

Flavonols pool distribution in the aerial mass of the <i>Bunias orientalis</i> L. in the North

The paper presents the results of a biochemical study of the aerial overburden mass of the Bunias orientalis L., grown under the conditions of the middle taiga subzone of the Republic of Komi according to the terms of its harvesting. The mass fraction of flavonols during the vegetative period of plants has been determined. It has been established that in mass budding and mass flowering phases in the row-leaves-buds (or flowers) the mass fraction of flavonols increases from 0,25% to 6,06% and from 0,6 to 15,43%, respectively. It is shown that when plants migrate to mass flowering, a sharp increase in the content of flavonols in all the above-ground organs of the plant is observed. A particularly large increase in the mass fraction of flavonols has been detected in the flowers of the overbearing of the eastern plants in comparison with the buds. Unconditional maximum of the pool of flavonols is observed in the flowers of the plant (15,43%). But, taking into account the fact that the mass fraction of flowers on the generative shoot is no more than 3%, in the technological plan, a promising source of flavonols from the aboveground mass of the studied plant are the leaves and flowers collected during the flowering phase in the Komi Republic in the third decade of June-July.

Metabolite profiling of flavonols and in vitro antioxidant activity of young shoots of wild Humulus lupulus L. (hop)

Humulus lupulus L., commonly named hop, is well-known for its sedative and estrogenic activity. While hop cones are widely characterized, only few works have been carried out on the young shoots of this plant. In the light of this, the aim of this study was to identify for the first time the flavonoids present in young hop shoots and to compare the composition of samples harvested from different locations in Northern Italy with their antioxidant activity. The samples were extracted by means of dynamic maceration with methanol. The HPLC-UV/DAD, HPLC-ESI-MS and MS2 analysis were carried out by using an Ascentis C18 column (250×4.6mm I.D., 5μm), with a mobile phase composed of 0.1M formic acid in both water and acetonitrile, under gradient elution. Quercetin and kaempferol glycosides were the main compounds identified and quantified in hop shoot extracts. Total flavonols ranged from 2698±185 to 517±48μg/g (fresh weight).The antioxidant activity was determined by means of the radical scavenging activity assay against diphenylpicrylhydrazyl (DPPH) and by using a photochemiluscence assay with a Photochem® apparatus. The results showed that hop shoots represent a new source of flavonols; therefore, they can be useful for a possible incorporation in the diet as a functional food or applied in the nutraceutical ambit.

Flavonoids in white and yellow perianths and yellow anthers of tulips (Tulipa gesneriana L.)

The content of flavonoids in white and yellow perianths and yellow anthers of a few tulip cultivars were determined at the stage of full flowering. To analyses of flavonols a HPLC method was used. In anthers (yellow) of all analyzed cultivars (Oscar, Pax, Profesor Wóycicki, Biała Dama, White Virgin, Calypso, Diana) high content of quercetin (2,35 - 6,01 mg·g<sup>-1</sup> F.W.), kaempferol (1,09 - 9,47 mg·g<sup>-1</sup> F.W.) and apigenin (1,34 - 8,24 mg·g<sup>-1</sup> F.W.) was found. In analyzed white perianth of cvs. Oscar and White Virgin also high content of quercetin (1,3 - 1,80 mg·g<sup>-1</sup> F.W.) and kaempferol (1,90 mg·g<sup>-1</sup> F.W.) was documented and only traces of apigenin was found. In the yellow perianth of cv. Profesor Wóycicki the level of quercetin and kaempferol was much lower than in perianth of cvs. Oscar and White Virgin, and apigenin was absent. Thus, yellow anthers and white and yellow perianth of tulip cultivars are a rich source of flavonols.

Effect of nano-encapsulated (-) epigallocatechin gallate on triglyceride accumulation in 3T3-L1 adipocytes

Background Obesity is considered the major risk factor for type 2 diabetes mellitus (T2DM), cardio-vascular diseases like hypertension and atherosclerosis [1]. Catechins are the major source of flavonols and they are comprised of various types of catechins such as epigallo catechin 3 gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) [2]. Numbers of in vivo studies have reported weight loss after drinking green tea for several months. To support these in vivo findings, many in vitro studies demonstrated effect of pure EGCG which is an important biologically active green tea catechin in reducing triglyceride accumulation in adipocytes [3]. However, these antiadipogenic properties of EGCG are greatly dependent on bio-availability which is very low in animals as well as in humans. One study showed that, peak plasma concentrations in humans were 1.3 μM for EGCG after a single dose of 1.5 mmol through oral administration [4]. Nanoencapsulated EGCG (Nano-EGCG) may help to increase bioavailability and to exert maximum anti-adipogenic effects.

Characterization of Industrial Onion Wastes (Allium cepa L.): Dietary Fibre and Bioactive Compounds

The food industry produces a large amount of onion wastes, making it necessary to search for possible ways for their utilization. One way could be to use these onion wastes as a natural source of high-value functional ingredients, since onion are rich in several groups of compounds, which have perceived benefits to human health. The objective of this work is to gain knowledge of any differences between the different onion wastes obtained from industry and non-commercial bulbs to use them as food ingredients rich in specific compounds. The results showed that brown skin and top-bottom could be potentially used as functional ingredient rich in dietary fibre, mainly in insoluble fraction, and in total phenolics and flavonoids, with high antioxidant activity. Moreover, brown skin showed a high concentration of quercetin aglycone and calcium, and top-bottom showed high concentration of minerals. Outer scales could be used as source of flavonols, with good antioxidant activity and content of dietary fibre. However, inner scales could be an interesting source of fructans and alk(en)yl cystein sulphoxides. In addition, discarded onions (cvs Recas and Figueres) could be used as a good source of dietary fibre, and cv Recas also as a source of phenolics compounds.

Dietary Flavonol and Flavone Intakes and Their Major Food Sources in Chinese Adults

The study aimed to estimate dietary flavonol and flavone intakes and investigate major dietary sources by FFQ in Harbin of China. A total of 5,046 volunteers completed a semiquantitative food frequency questionnaire (FFQ). A random subsample of 167 healthy subjects completed the 7 consecutive 24-h dietary recalls and 2 FFQ for assessing the reproducibility and validity of FFQ. The correlation coefficients between 2 FFQ were 0.72 for flavonols and 0.65 for flavones; and between FFQ 2 and the 24-h dietary recall, they were 0.62 for flavonols and 0.58 for flavones. When flavonol and flavone intakes were categorized by quartile, complete and partial agreement ranged from 76% to 84%. The total intake of flavonols and flavones was 19.13 mg/day, and the mean flavonol and flavone intakes were 14.30 mg/day and 4.82 mg/day, respectively. Quercetin was the major contributor (31%) to total intake of flavonols and flavones, followed by kaempferol (22%). The main food sources of flavonols and flavones were apple (12%), potato (8%), celery (7%), eggplant (7%), and actinidia (5%). This work could facilitate the investigation on the proposed relation between these flavonoids and the prevention of chronic diseases.

Flavonols in fresh and processed Brazilian fruits

Flavonols (myricetin, quercetin and kaempferol) and flavones (luteolin and apigenin) were determined in Brazilian fruits, using a previously optimized and validated HPLC method. The flavonoids investigated were not detected in three cultivars each of mango and papaya. Quercetin was found in all the other fruits, the mean values varying from 0.3 mg/100 g in orange cultivar Pêra to 7.5 mg/100 g in apple cultivar Fuji. Kaempferol was encountered in strawberry (0.7–0.9 mg/100 g), acerola (0.9–1.2 mg/100 g), pitanga (0.4 mg/100 g) and cashew-apple (<LQ–0.3 mg/100 g). Myricetin was detected only in pitanga (3.1–3.7 mg/100 g) and cashew-apple (2.0 mg/100 g). The best sources of flavonols among the fruits investigated were pitanga, cashew-apple, acerola and apple, the first three being analyzed for the first time. Luteolin and apigenin were not detected in any of the fruits. The processed products (ready-to-drink juice, concentrated juice, frozen pulp) of acerola, cashew-apple and pitanga had appreciably lower flavonol levels than the unprocessed fruit, indicating losses during processing. Comparison with published data on apple, orange, strawberry and fig shows the need for interlaboratory evaluation of the analytical methodology and more analyses to obtain cultivar-specific data.

Conteúdo de miricetina, quercetina e kaempferol em chás comercializados no Brasil

Os teores de miricetina, quercetina e kaempferol foram determinados em uma marca de ban-chá, duas de chá verde e quatro de chá preto. Analisaram-se três lotes para cada marca em duplicata por cromatografia líquida de alta eficiência. Quercetina (2,5-3,4 mg/g folha seca) predominou em todas as amostras, seguida por kaempferol (1,0-2,0 mg/g folha seca), com exceção de uma amostra na qual kaempferol e miricetina tiveram teores iguais. Houve variação entre os tipos de chás e mesmo entre marcas do mesmo tipo. Miricetina (traços - 1,9 mg/g folha seca) foi o flavonol, que mais variou e que esteve em menor nível nos chás pretos. Outros chás muito consumidos no Brasil também foram investigados. A miricetina não foi encontrada em chás de frutas (maçã e morango) e de ervas (erva doce, camomila, erva cidreira, hortelã, boldo, mate e erva mate), enquanto que quercetina foi encontrada em quatro chás (camomila, boldo, morango e erva mate) e kaempferol, em dois chás (boldo e erva-mate), em concentrações de 0,4 a 2,5 e 0,4 a 2,6 mg/g de folha seca, respectivamente. Concluiu-se que estes chás são fontes de flavonóis na dieta brasileira, embora com teores menores que em chás verde e preto.

Biothiols, Taurine, and Lipid-Soluble Antioxidants in the Edible Pulp of Sicilian Cactus Pear (Opuntia ficus-indica) Fruits and Changes of Bioactive Juice Components upon Industrial Processing

Biothiols, taurine, and flavonols, as well as tocopherols and carotenoids have been assessed in the edible pulp of Sicilian red (Sanguigna), yellow (Surfarina), and white (Muscaredda) cultivars of cactus pear. The yellow cultivar has the highest level of reduced glutathione (GSH, 8.1 +/- 0.78 mg/100 g pulp), whereas the white cultivar showed the highest amount of cysteine (1.21 +/- 0.12 mg/100 g pulp). Taurine accounted for 11.7 +/- 1.0 mg/100 g in the yellow pulp, while lower levels were measured in the others. With the exception of kaempferol in the yellow cultivar (2.7 +/- 0.2 microg/100 g pulp), the edible pulp of cactus pear was not a source of flavonols. Very low amounts of lipid-soluble antioxidant vitamins such as vitamin E and carotenoids were measured in all cultivars. As a consequence of industrial processing, a total loss of GSH and beta-carotene and a net decrease of vitamin C and cysteine were revealed in the fruit juice, whereas betalains, taurine, and vitamin E appeared to be less susceptible to degradation.