Major Classes Of Flavonoids Research Articles

Genetic analysis of gene expression for pigmentation in Chinese cabbage (Brassica rapa)

Anthocyanins are a major class of flavonoids that are produced in the tissues of many plant species in response to environmental signals. The pigmentation of Chinese cabbage (Brassica rapa) was analyzed using newly developed 300K Brassica rapa microarrays. The significantly expressed genes were analyzed by clusters of orthologous groups (COGs) and hypergeometric analyses for transcription factors associated with anthocyanin pigmentation. The candidate genes were classified into 11 groups that exhibited functionally diverse transcription factor activity involved in anthocyanin-based pigmentation. Thirty-eight unknown genes were identified that potentially play a role in anthocyanin biosynthesis. Three of these unknown genes differed dramatically among cabbage leaves with yellow, green, or red pigmentation. These three genes may play a regulatory role in the anthocyanin production process or may be related to anthocyanin metabolism during flavonoid biosynthesis. These results show functional diversity of transcription factor families and that the biological functions of the anthocyanin-related transcription factors may be activated in a pigmentation signaling pathway in Chinese cabbage (Brassica rapa).

Flavonoids and the Risk of Oral and Pharyngeal Cancer: A Case-Control Study from Italy

The intake of flavonoids has been inversely related to the risk of various common neoplasms, but scanty data exist on oral and pharyngeal cancer. We used data from a case-control study conducted in Italy between 1992 and 2005 to examine the relationship between flavonoid intake and oral and pharyngeal cancer risk. The study included 805 cases with incident, histologically confirmed oral and pharyngeal cancer, and 2,081 hospital controls admitted for acute, nonneoplastic conditions. We have applied data on food and beverage content of six major classes of flavonoids, on dietary information collected through a validated food-frequency questionnaire. The odds ratios (OR) were calculated using multiple logistic regression models, conditioned on study center, sex, and age. After adjustment for education, tobacco, alcohol, body mass index, and non-alcohol energy intake, ORs for the highest versus the lowest quintile of intake were 0.51 [95% confidence intervals (95% CI), 0.37-0.71] for flavanones, 0.62 (CI, 0.43-0.89) for flavonols, and 0.56 (95% CI, 0.40-0.78) for total flavonoids. No significant association emerged for isoflavones (OR, 0.90), anthocyanidins (OR, 0.86), flavan-3-ols (OR, 0.84), and flavones (OR, 0.75). The ORs were consistent across strata of age, sex, education, body mass index, tobacco, and alcohol. After allowance for vegetable and fruit consumption, the inverse relations with total flavonoids and flavanones remained significant, whereas that with flavonols became nonsignificant. None of the associations were significant after further allowance for vitamin C, probably on account of the high collinearity between these compounds.

Flavonoids and the Risk of Renal Cell Carcinoma

Intake of flavonoids has been inversely related to the risk of various common neoplasms, but limited data exist on renal cell carcinoma (RCC). We used data from a case-control study conducted between 1994 and 2002 in four Italian areas to study the relation between major flavonoid classes and RCC. The study included 767 cases with incident, histologically confirmed RCC and 1,534 hospital controls admitted for acute, nonneoplastic conditions and matched with cases by study center, sex, and quinquennia of age. We applied published data on food and beverage content of six major classes of flavonoids to dietary information collected through a validated food frequency questionnaire. After adjustment for major recognized confounding factors and total energy intake, the odds ratios for subjects in the highest versus the lowest quintile of intake were 0.80 [95% confidence interval (95% CI), 0.58-1.11] for total flavonoids, 0.76 (95% CI, 0.56-1.03) for isoflavones, 0.94 (95% CI, 0.60-1.47) for anthocyanidins, 0.77 (95% CI, 0.56-1.06) for flavan-3-ols, 0.90 (95% CI, 0.67-1.21) for flavanones, 0.68 (95% CI, 0.50-0.93) for flavones, and 0.69 (95% CI, 0.50-0.95) for flavonols. Allowance for vegetable and fruit consumption only partly explained these inverse relations. Thus, flavonoids, and particularly flavones and flavonols, may account, at least in part, for the favorable role of plant foods on RCC.

Flavonoids and Prostate Cancer Risk: A Study in Italy

: Flavonoids have been associated with a reduced risk of lung, digestive tract, and certain hormone-related cancers. With reference to prostate cancer, a few epidemiological studies have found an inverse relation with intake of isoflavones, flavonols, and flavones, although the evidence remains limited and inconsistent. The role of six principal classes of flavonoids on prostate cancer was investigated using data from a multicentric case-control study conducted between 1991 and 2002 in Italy. This included 1,294 incident, histologically confirmed carcinomas of the prostate and 1,451 controls admitted to the same hospitals as cases for a wide spectrum of acute, non-neoplastic conditions. The patients' usual diet was assessed using a validated and reproducible food-frequency questionnaire; food and beverage content of six major classes of flavonoids was obtained from the U.S. Department of Agriculture. No association between prostate cancer risk was found with any of the flavonoids analyzed: the multivariate odds ratios for the highest versus the lowest quintile of intake were 0.96 (95% confidence interval, CI = 0.75–1.23) for flavanones, 1.3 (95% CI = 1.01–1.69) for flavan-3-ols, 1.23 (95% CI = 0.95–1.61) for flavonols, 1.09 (95% CI = 0.85–1.40) for flavonols, 1.18 (95% CI = 0.91–1.53) for anthocyanidins, 0.98 (95% CI = 0.76–1.26) for isoflavones, and 1.20 (95% CI = 0.92–1.58) for total flavonoids, all nonstatistically significant. Thus, the results of the present study do not support a protective effect of flavonoids on prostate cancer in this Italian population, characterized by a high intake of flavonoid-containing foods (except isoflavone-rich foods).

Flavonoids Attenuate Cardiovascular Disease, Inhibit Phosphodiesterase, and Modulate Lipid Homeostasis in Adipose Tissue and Liver

Plant flavonoids are widely distributed polyphenolic compounds of the human diet. They consist of six major classes based on specific structural differences: flavonols, flavones, flavanones, catechins, anthocyanidins, and isoflavones. All of the major classes of flavonoids are comprised of three six-membered rings: an aromatic A-ring fused to a heterocyclic C-ring that is attached through a single carbon-carbon bond to an aromatic Bring. Population studies have shown that flavonoid intake is inversely correlated with mortality from cardiovascular disease, and numerous flavonoids of dietary significance have been shown to beneficially impact parameters associated with atherosclerosis, including lipoprotein oxidation, blood platelet aggregation, and vascular reactivity. Therapeutic effects of flavonoids on platelet aggregability and blood pressure have been attributed to competitive inhibition of cyclic nucleotide phosphodiesterase (PDE), an elevation in cAMP level, and subsequent activation of protein kinase A (cAMP-dependent protein kinase). In addition, flavonoids may induce neutral lipid hydrolysis from lipid stores through PDE inhibition in adipose tissue and liver. Indeed, the three-dimensional structure of many flavonoids is sterically and electrostatically compatible with the catalytic site of cAMP PDE3 and PDE4. Flavonoids have also been reported to suppress pathways of lipid biosynthesis and of very low-density lipoprotein production in cultured hepatocytes. Continued studies of the biochemical mechanisms underlying the biological effects of plant flavonoids may uncover new strategies for the treatment of cardiovascular disease, as well as associated conditions such as obesity, hepatic steatosis, and Type 2 diabetes.

Flavonoids, vitamin C and adenocarcinoma of the stomach.

To examine the role of six flavonoid classes (flavanones, flavan-3-ols, flavonols, flavones, anthocyanidins and isoflavones) and vitamin C in the aetiology of stomach cancer. Case-control study undertaken in Greece in the 1980s. Dietary information was obtained from 110 patients with incident stomach adenocarcinoma and 100 control patients. Flavonoid estimates were based on the recently released database of the US Department of Agriculture. In models including sociodemographic variables, energy intake, vegetables, fruits and, alternatively, vitamin C the six flavonoid classes, only flavanones and vegetables remained significantly inversely associated with stomach cancer risk. The odds ratio (95% confidence intervals) per one standard deviation increase of intake of flavanones was 0.55 (0.31-0.96) whereas for vitamin C it was 1.05 (0.46-2.41). When fruits and vegetables were not adjusted for, both vitamin C and several flavonoid categories were inversely associated with stomach cancer risk, but these associations could be attributed to other compounds in these foods. Among the major flavonoid classes studied, only flavanone intake is inversely associated with stomach cancer risk and could account for the apparent protective effect of fruit intake against this form of cancer. Additional factors, however, are likely to be involved in the consistent protection conveyed by vegetables.

Biosystematics of the monocotyledoneae—flavonoid patterns in leaves of the liliaceae

In a leaf survey of 168 species of the Liliaceae, most of the major flavonoid classes were found to be represented in the family. Flavonols occurred most frequently: quercetin and kaempferol were detected in 40% and 42% of the sample respectively, while the flavones luteolin and apigenin were present in only 24% and 20% of the sample. Methylated derivatives, i.e. isorhamnetin, diosmetin and tricin were rare. Procyanidins were present in 17 species, flavonoid sulphates in only one species and flavone C-glycosides in only three species. Anthraquinone pigments were identified in species of Aloe Asphodeline and Asphodelus. Three new flavonoid glycosides were characterised during the course of the survey: diosmetin 7-diglucoside in Colchicum byzanthinum and tricin 7-fructosylglucoside and tricin 7-rutinoside-4′-glucoside in Hyacinthus orientalis cv. ‘Quean of the Pinks’. On the basis of the flavonoid survey, the subfamilies of the Liliaceae may be grouped into those containing flavonols only, those with flavones only or those having both flavonols and flavones. Members of the related families: Amaryllidaceae (17 species), Agavaceae (1 species) and Xanthorrhoeaceae (1 species) contained only flavonols. The subfamilies Scilloideae, Asphodeloideae and Melanthioideae show the most chemical variation whilst the Wurmbaeoideae and Lilioideae are the most homogeneous groups. The tribe Scilleae is unusual in that both flavone- and flavonol-containing genera occur and a wide variety of flavonoid types are represented. A comparison of the leaf flavonoids of the Liliaceae with those found in families related to the grasses showed that all except two classes of flavonoid compound (5-methylated flavones and 5-deoxyflavonoids) found in the Juncaceae. Cyperaceae, Palmae and Gramineae are present in the Liliaceae thus supporting the view that all four families could have arisen from Liliaceae-like ancestors.