Total Flavanones Research Articles

Flavonoid intake and the risk of age-related cataract in China's Heilongjiang Province

Background/objectivesEpidemiological evidence suggests that diets rich in flavonoids may reduce the risk of developing age-related cataract (ARC). Flavonoids are widely distributed in foods of plant origin, and the objective of this study was to evaluate retrospectively the association between the intakes of the five flavonoid subclasses and the risk of ARC.Subjects/methodsA population-based case-control study (249 cases and 66 controls) was carried out in Heilongjiang province, which is located in the northeast of China, and where intakes and availability of fresh vegetables and fruits can be limited. Dietary data gathered by food-frequency questionnaire (FFQ) were used to calculate flavonoid intake. Adjusted odds ratio (OR) and 95% confidence interval (CI) were estimated by logistic regression.ResultsNo linear associations between risk of developing ARC and intakes of total dietary flavonoids, anthocyanidins, flavon-3-ol, flavanone, total flavones or total flavonols were found, but quercetin and isorhamnetin intake was inversely associated with ARC risk (OR 11.78, 95% CI: 1.62–85.84, p<0.05, and OR 6.99, 95% CI: 1.12–43.44, p<0.05, quartile 4 vs. quartile 1, respectively).ConclusionAs quercetin is contained in many plant foods and isorhamnetin in very few foods, we concluded that higher quercetin intake may be an important dietary factor in the reduction of the risk of ARC.

자몽껍질 유래 플라바논의 최적 추출 및 기능성 소재 캡슐화

버려지는 자몽 껍질에 다량 함유되어있는 플라바논을 추출하여 기능성 성분을 재이용하였다. 친환경용매인 아임계수 추출기술을 이용하여 <TEX>$170^{\circ}C$</TEX>, 10 min의 최적 조건에서 추출함으로써 무독성 용매로 빠르고 경제적으로 추출할 수 있었다. 자몽껍질 추출물을 <TEX>${\beta}$</TEX>-cyclodextrin을 이용하여 처리함으로써 플라바논과 같은 비극성 물질을 캡슐화하여 소재의 가용화를 용이하게 하였다. 이것은 항산화 기능이 향상된 대체 소재의 개발 및 건강지향식품에 이용할 수 있으며, 이를 통하여 세계 기능성 식품 시장으로의 진출을 위한 발판으로도 삼을 수 있을 것으로 기대된다. The extraction of flavanones such as naringin, narirutin, naringenin, hesperidin, and hesperetin from grapefruit peels was performed using subcritical water extraction (SWE), hot water extraction, and conventional methods such as methanol and ethanol extraction. We analyzed the total flavanone content using high-performance liquid chromatography (HPLC) for each extracting method. Among the three methods, SWE was the optimal method with optimal operating conditions of <TEX>$170^{\circ}C$</TEX> temperature and 10 min operating time. The maximum total flavanone extracted was <TEX>$86.539{\pm}3.52mg/g$</TEX> grapefruit peels. Moreover, we treated the extracts with 60% <TEX>${\beta}$</TEX>-cyclodextrin and then analyzed the surface structure of the encapsulated compounds by field emission-scanning electron microscopy (FE-SEM). The results indicated that the encapsulation in <TEX>${\beta}$</TEX>-cyclodextrin improved solubilization, and the inclusion complex could serve as food supplements.

A nano‐LC/UV method for the analysis of principal phenolic compounds in commercial citrus juices and evaluation of antioxidant potential

In this study, a simple and rapid methodology to analyze and quantify principal flavanones in citrus fruit juices through the use of a nano-LC/UV-Vis apparatus, employing a 75 μm id capillary column packed with sub-2 μm particles C18 stationary phase for 10 cm, was developed. All compounds were baseline resolved working with a step gradient elution mode in 10 min. The developed analytical method was validated and the resulting RSD% for intra- and interday repeatability, related to retention time and peak area, were <4.7 and 5.5%, respectively. LOD and LOQ values corresponded to 0.40 and 1.56 μg/mL for didymin, hesperitin, and narinegenin, while for the other flavanones were 0.78 and 3 μg/mL, respectively. Good linearity with acceptable determination coefficients R(2) was obtained in the range between LOQ concentration and 200 μg/mL (500 μg/mL naringin and hesperidin). Good recovery values were also obtained. Then, the method was applied to the analysis of selected hand-squeezed and commercial citrus juices. Further, the nano-LC system was coupled to a mass spectrometer to confirm analyte identification. Antioxidant capacity of selected samples was also evaluated measured by Folin-Ciocalteu assay and Trolox equivalent antioxidant capacity assay. Results were compared to determine total flavanones concentrations.

Effect of arbuscular mycorrhizal fungi and phosphorus concentration on plant growth and phenols in micropropagated Aloe vera L. plantlets

The objective of this work was to investigate the effect of two arbuscular mycorrhizal fungi (AMF) and different phosphorus (P) concentrations on growth and phenolic concentration inAloe vera L. plantlets obtained from micropropagation. Plantlets were multiplied in vitro, acclimatized and inoculated with Glomus claroideum or Glomus fasciculatum at three P concentrations, that is, 0.3, 0.6 or 0.9 mM P. After 90 days in ex vitro, plant height, number of leaves, mycorrhization percent, fresh and dry weight, and total phenol, flavonol and flavanone concentrations in leaves was determined. Inoculating A. vera plantlets with G. fasciculatum reduced plant fresh and dry weight compared to the plants inoculated with G. claroideum or left uninoculated. The concentration of flavonols and flavanones increased whenA. vera plantlets were inoculated with both AMF with the largest increase found in G. fasciculatum. Mycorrhization percent decreased with increased P and the concentration of flavanones was lower in plants fertilized with 0.9 mM P than in those with 0.3 or 0.6 mM P. Key words: Flavonols, flavanones, Glomus claroideum, Glomus fasciculatum, total phenol concentration.

Flavonoids, Proanthocyanidins, and Cancer Risk: A Network of Case-Control Studies From Italy

We considered flavonoids and proanthocyanidins in a network of multicentric Italian case-control studies including about 10,000 incident, histologically confirmed cases of selected cancers and over 16,000 controls. Odds ratios (ORs) for the highest vs. the lowest quintile of 6 classes of flavonoids and proanthocyanidins were estimated by multiple logistic regression models. Total flavonoids, flavanones, and flavonols were inversely related to oral and laryngeal cancers (ORs, respectively 0.56 and 0.60 for total flavonoids; 0.51 and 0.60 for flavanones; and 0.62 and 0.32 for flavonols). Flavanols were also inversely related to laryngeal cancer (OR = 0.64), whereas flavanones were inversely related to esophageal cancer (OR = 0.38). A reduced risk of colorectal cancer was found for high intake of anthocyanidins (OR = 0.67), flavonols (OR = 0.64), flavones (OR = 0.78), and isoflavones (OR = 0.76). Inverse relations with breast cancer were found for flavones (OR = 0.81) and flavonols (OR = 0.80). Flavonols (OR = 0.63) and isoflavones (OR = 0.51) were inversely associated to ovarian cancer, whereas flavonols (OR = 0.69) and flavones (OR = 0.68) were inversely associated to renal cancer. No association between flavonoids and prostate cancer emerged. We found inverse associations between proanthocyanidins and colorectal cancer. These associations appeared stronger for proanthocyanidins with a higher degree of polymerization (OR = 0.69 for ≥ 10 mers).

Concentration and Solubility of Flavanones in Orange Beverages Affect Their Bioavailability in Humans

Orange juice is a very rich source of dietary flavanones. The effect of flavanone concentration and solubility of orange beverages on their bioavailability has been studied in a crossover study with 10 healthy volunteers. Five different beverages with different flavanone concentrations were evaluated. Commercial orange juices (29.2-70.3 mg of flavanones/100 mL) were compared with experimental orange beverages in which the flavanone concentration was enhanced (110.2 mg/100 mL). Hesperetin and naringenin glucuronides and sulfates were detected and quantified in plasma and urine. The study shows that the solubility of the flavanones, and particularly that of hesperidin, in the juice is a key factor for the bioavailability as flavanone excretion and the C(max) in plasma correlate well with the soluble flavanone concentration in the juice, whereas it has no correlation with the total flavanone intake. In addition, a large interindividual variation was observed, this being consistent for each individual after the intake of the different beverages, suggesting that flavanone bioavailability is also dependent on the occurrence of specific microbiota that is able to remove the rutinosides from the juice glycosides, which results in aglycones that are then absorbed from the gut.

A validated spectrophotometric method for quantification of prenylated flavanones in pacific propolis from Taiwan

Because of its chemical diversity, the only way to standardise propolis is to specify multiple standards for different propolis types according to the corresponding chemical profile. So far, this has been done only for European propolis. To develop a rapid low-cost spectrophotometric procedure for quantification of bioactive prenylated flavanones in Taiwanese propolis. The proposed method quantifies the total flavanones on the basis of their absorption as coloured phenylhydrazones formed by interaction with 2,4-dinitrophenylhydrazine. The procedure was validated through model mixture of compounds representing the composition of Taiwanese propolis according to previous studies. The major flavanones of the propolis samples (propolins C, D, F and G) were quantified by HPLC. Antiradical activity against DPPH was also measured. The DNP (dinitrophenylhydrazine) spectrophotometric method is applied for the first time for quantification of prenylated flavanones. Spectophotometric procedure applicable to new type propolis (Macaranga type) was developed with recovery between 105 and 110% at the concentration range of 0.573-1.791 mg/mL. Six propolis samples were analysed by spectrophotometry using the procedure developed and validated, and by HPLC as the results demonstrated satisfactory agreement. Neither the spectrophotometric data nor the values measured by HPLC showed significant correlation with the antiradical activity against DPPH. The proposed spectrophotometric procedure is useful for routine analyses of Macaranga-type propolis, because of its simplicity, repeatability and acceptable accuracy. Its application to a number of commercial samples could be used as a basis for standardisation and quality control of Pacific propolis.

EXAMINATION OF ANTIOXIDANT CAPACITY OF BEEBREAD EXTRACTS BY DIFFERENT COMPLEMENTARY ASSAYS

Total phenolic and flavonoid content were measured in different solvent extracts of beebread, as well as their antioxidant capacity. The content of total polyphenols was quantified according to the Folin-Ciocalteau method. The flavonoid estimation was made using two complementary colorimetric methods, using both aluminum chloride reaction (according to a modified Dowd method) and 2, 4-dinitrophenylhydrazine. The samples content varied between 22.72- 8.32 mg GAE g-1 (total phenols), 0.696-0.168 mg QE g-1 (flavonols, flavones and isoflavones) respectively 7.86-3.12 mg NAE g-1 (total flavanones). The antioxidant capacity was determined by free radical scavenging (DPPH 2,2-diphenyl-picrylhydrazyl) method, by ferric reducing antioxidant power (FRAP) and by ABTS (3-ethyl-benzothiazoline-6-sulfonic acid) assays. Good correspondences between the antioxidant activity and the content of total phenols and flavonoids of beebread extracts were found.

Flavanone metabolism in healthy and tumor-bearing rats

Flavanones, the main polyphenols of citrus fruits, are thought to contribute to the protective effects of these fruits against cardiovascular diseases and cancer. The metabolism of naringin (naringenin 7- O-neohesperidoside) is studied here in healthy (sham-operated, ShO) and tumor-bearing (TuB) rats. The tumor was induced by implanting Yoshida's sarcoma in hindlimb. Both groups received for 7 days a semi-synthetic diet containing 0.5% naringin in per feeding conditions. Flavanones were analyzed in plasma, liver, kidney and urine by tandem mass spectrometry. Naringenin conjugates (essentially glucuronides) accounted for up to 98% of the total flavanones in plasma. Low amounts of hesperetin (4′- O-methyl naringénine) and isosakuranetin (3′-hydroxy-4′- O-methylnaringenin) were also detected in all biological samples and accounted for 2% of the total flavanones in plasma. They were largely present as aglycones. The in vivo hydroxylation of flavanones is described here for the first time. Total concentrations of naringenin metabolites reached 17.3 ± 2.7 μM in plasma 6 hours after the beginning of the meal in healthy rats and only 10.6 ± 1.3 μM in TuB rats. The nature of metabolites was similar in both healthy and TuB rats and in plasma, tissues and urine. The lower concentration of flavanones in the TuB rats suggests that disease and more particularly cancer, may affect the bioavailability of flavonoids.

Chemical diversity of propolis and the problem of standardization

Chemical variability of propolis is discussed with respect to the problem of standardization. Several chemical types of propolis are formulated, based on their plant source. Reliable criteria for chemical standardization of different propolis types are needed but such generally accepted criteria do not yet exist. The chemical profile of “poplar” propolis, typical for the temperate zone, can be characterized by the following parameters: total flavone and flavonol content, total flavanone and dihydroflavonol content, and total phenolics content. These parameters correlate better with the biological activity and are more informative that the quantification of individual components. There is still a lot of work to be done to achieve standardization of other propolis types. Working with standardized material will allow scientists to connect a particular chemical propolis type to a specific type of biological activity and formulate recommendations for mainstream practitioners.

Influence of industrial processing on orange juice flavanone solubility and transformation to chalcones under gastrointestinal conditions.

Orange juice manufactured at industrial scale was subjected to digestion under in vitro gastrointestinal conditions (pH, temperature, and enzyme and chemical conditions) to evaluate the influence of individual industrial processing treatments on flavanone solubility, stability, and ability to permeate through a membrane under simulated physiological conditions. Four industrial processes including squeezing, standard pasteurization, concentration, and freezing were evaluated. Hand squeezing was compared with industrial squeezing. After in vitro gastrointestinal digestion of the orange juices, the flavanones able to permeate through a dialysis membrane, and those remaining in the retentate were evaluated by HPLC as were those present in the insoluble fraction. In all of the assayed orange juices, a high content of precipitated chalcones ( approximately 70% of the total flavanones) was formed under the physiological conditions of the gastrointestinal tract. Hand squeezing provided a higher concentration of flavanones in the permeated fraction and lower transformation to chalcones than industrial squeezing. Standard pasteurization did not influence the solubility and permeability of the orange juice flavanones and chalcones. Industrial concentration did not affect the amount of flavanones able to permeate but decreased the chalcones produced. Juices produced from frozen orange juice contained considerably smaller amounts of both soluble flavanones and insoluble chalcones.

Changes in limonin and naringin levels in grapefruit albedo with maturity and the effects of gibberellic acid on these changes

Variability in the two major bitter components, naringin and limonin, in grapefruit peel albedo was determined over four seasons in Marsh grapefruit. The effects of the growth regulator gibberellic acid (GA) on seasonal content of these two bitter components in albedo was also determined. Limonin and naringin content decreased with maturity and were affected by some treatments with (GA). In Marsh grapefruit albedo, naringin was the major flavanone glycoside, representing more than 80% of the total flavanones. In a non-bitter grapefruit hybrid, only traces of naringin were present in the albedo, and the non-bitter isomer naringenin 7β-rutinoside was the major flavonoid present.