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PubMed1997

Phytochemicals: guardians of our health.

Consuming a diet rich in plant foods will provide a milieu of phytochemicals, nonnutritive substances in plants that possess health-protective benefits. Nuts, whole grains, fruits, and vegetables contain an abundance of phenolic compounds, terpenoids, pigments, and other natural antioxidants that have been associated with protection from and/or treatment of chronic disease such as heart disease, cancer, diabetes, and hypertension as well as other medical conditions. The foods and herbs with the highest anticancer activity include garlic, soybeans, cabbage, ginger, licorice, and the umbelliferous vegetables. Citrus, in addition to providing an ample supply of vitamin C, folic acid, potassium, and pectin, contains a host of active phytochemicals. The phytochemicals in grains reduce the risk of cardiovascular disease and cancer.

Citrus↗
PubMed2001

Predicting quantitative phytochemical markers in single Echinacea plants or clones from their DNA fingerprints.

Amplified restricted fragment length polymorphism (AFLP) data analysis was found to be a statistically significant predictor of phytochemical markers in cultivated Echinacea purpurea germplasm and some related wild species. Over 50 accessions grown under greenhouse conditions were subjected to AFLP analysis and the same assessed for content of tetraene and cichoric acid by high pressure liquid chromatography. The first and second canonical correlation of DNA variables and the phytochemical variables were significant. Individual regressions of cichoric acid and dodeca-2E, 4E, 8Z, 10E/Z-tetraenoic acid isobutyl amide predicted by DNA polymorphism analysis against actual HPLC determined values were nearly linear. Mantel's test showed that there was a weak correlation but a strong association of values of the phytochemical variables and the DNA polymorphism data.

Arachidonic Acids↗
PubMed1997

The estrogenic and antiestrogenic activities of phytochemicals with the human estrogen receptor expressed in yeast.

We have used the expression of the human estrogen receptor (hER) and two estrogen response elements linked to the lacZ gene in yeast (YES) to study the estrogenic and antiestrogenic activities of various phytochemicals. Coumestrol, alpha-zearalenol, or genistein could produce beta-galactosidase activity comparable to estradiol, but these required concentrations 100 to 1000-fold greater than estradiol. These compounds did not possess antiestrogenic activity. Narigenin, kaempferide, phloretin, biochanin A, flavone, or chrysin only partially induced beta-galactosidase activity in the YES at any concentration tested. When narigenin, kaempferide, or phloretin was given concurrently with estradiol, the estradiol-dependent beta-galactosidase activity was not inhibited by more than 50%. However, biochanin A, flavone, or chrysin could inhibit the activity of estradiol in a dose-response manner with IC50 values of 500 nM, 2 microM, and 10 microM, respectively. Combinations of biochanin A, chrysin, and flavone decreased estradiol-dependent beta-galactosidase activity in an additive fashion. Similar to the antiestrogens tamoxifen or ICI 182, 780, the antiestrogenic activity of these compounds with the exception of chrystin involved the disruption of hER dimerization, as demonstrated in the yeast two-hybrid system. Biochanin A, chrysin, or flavone were less effective in inhibiting the activity of an estrogenic polychlorinated biphenyl than they were inhibiting the activity of estradiol. Interestingly, this latter group of antiestrogenic phytocompounds did not inhibit the estrogenic activity of such phytochemicals as coumestrol or genistein. These results suggest that the antiestrogenic activity of biochanin A and flavone occurs by a mechanism similar to tamoxifen or ICI 182,780. Moreover, it seems that phytochemicals functioning as antiestrogens do not inhibit the activity of all estrogenic chemicals to the same extent. This suggests that conformational changes induced by different estrogens bound to the hER may regulate the antiestrogenic activity of a compound.

Anticarcinogenic Agents↗
PubMed2001

Disparate effects of similar phenolic phytochemicals as inhibitors of oxidative damage to cellular DNA.

Phenolic phytochemicals are natural plant substances whose cellular effects have not been completely determined. Nordihydroguaiaretic acid (NDGA) and curcumin are two phenolic phytochemicals with similar molecular structures, suggesting that they possess comparable chemical properties particularly in terms of antioxidant activity. To examine this possibility in a cellular system, this study evaluated the capacities of NDGA and curcumin to function as antioxidants in inhibiting oxidative damage to DNA. Jurkat T-lymphocytes were pre-incubated for 30 min with 0-25 microM of either NDGA or curcumin to allow for uptake. The phenolic phytochemical-treated cells were then oxidatively challenged with 25 microM hydrogen peroxide (H2O2). Afterwards, cells were subjected to alkaline micro-gel electrophoresis (i.e. comet assay) to assess the extent of single-strand breaks in DNA. In a concentration-dependent manner, NDGA inhibited H2O2-induced DNA damage, whereas curcumin did not. In fact, incubating Jurkat T-lymphocytes with curcumin alone actually induced DNA damage. This effect of curcumin on DNA did not appear to reflect the DNA fragmentation associated with apoptosis because there was no proteolytic cleavage of poly-(ADP-ribose)-polymerase, which is considered an early marker of apoptosis. Curcumin-induced damage to DNA was prevented by pre-treatment of the cells with the lipophilic antioxidant, alpha-tocopherol, suggesting that curcumin damaged DNA through oxygen radicals. Therefore, it is concluded that NDGA has antioxidant activity but curcumin has prooxidant activity in cultured cells based on their opposite effects on DNA.

Antioxidants↗
PubMed2002

Phytochemicals in plants: genomics-assisted plant improvement for nutritional and health benefits.

Plants are an important source of essential nutrients and health-beneficial components that are crucial for human life. Because the intake of these phytochemicals is not always adequate, the resources of plant biotechnology are being used to enhance the nutritional quality of our plant-based food supply. Various improvement strategies are feasible, depending on whether the phytochemical target is a major or minor constituent. Recent efforts in gene discovery and functional genomics are providing the necessary understanding to develop and evaluate different approaches to manipulate phytochemical composition.

Diet↗
PubMed2005

Use of cancer chemopreventive phytochemicals as antineoplastic agents.

A lot of information has been gathered on cellular mechanisms by which chemopreventive phytochemicals, such as curcumin (a spice in curry) or epigallocatechin gallate (extracted from tea), interfere with carcinogenesis. A comparison of this knowledge with what we know about molecularly targeted chemotherapeutic agents suggests that it might be worthwhile to investigate the usefulness of such phytochemicals in the treatment of established malignant diseases. Phytochemicals use a plethora of antisurvival mechanisms, boost the host's anti-inflammatory defence, and sensitise malignant cells to cytotoxic agents. The restricted systemic availability of agents such as curcumin and epigallocatechin gallate, needs to be taken into account if they are to be developed as cochemotherapeutic drugs.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Phytochemical variation in echinacea from roots and flowerheads of wild and cultivated populations.

Quantitative phytochemical variation was determined from roots and inflorescences of native plant populations in the genus Echinacea. Specimens were collected in situ throughout the natural range of each putative taxon and transplanted to greenhouse cultivation. Ethanolic extracts from individual plants were separated by reversed-phase HPLC to quantify the alkamides, polyenes/ynes, and phenolics, and then grouped by age and taxonomically, according to a recent morphometric taxonomic revision of the genus. Canonical discriminant analysis revealed that cichoric acid, the diene alkamides 1-3 and 7, and ketoalkene 24 were the best taxonomic markers. Mean content for each of 26 phytochemicals revealed useful agronomic information, such as those varieties and organs with the highest accumulations, as well as the optimal age and growth conditions for each variety. The highest amounts of cichoric acid were measured from the older, wild inflorescences of E. pallida var.sanguinea, whereas the highest quantities of the alkamides 1-3 and 7 were present in roots of wild and transplanted E. purpurea. Baseline phytochemical data and chromatographic profiles for all types of wild Echinacea may be used for protection of wild stands, germplasm identification, and crop improvement.

Caffeic Acids↗
PubMed2003

Phytochemical profiles and antioxidant activity of wheat varieties.

Whole grain consumption has been associated with reduced risk of chronic diseases, such as cardiovascular diseases and cancer. These beneficial effects have been attributed to the unique phytochemicals of grains that complement those found in fruits and vegetables. Wheat is one of the major grains in the human diet; however, little is known about the inherent varietal differences in phytochemical profiles, total phenolic and carotenoid contents, or total antioxidant activities of different wheat varieties, which ultimately influence the associated nutritional and health benefits of wheat and wheat products. The objectives of this study were to determine the phytochemical profiles and total antioxidant activity for 11 diverse wheat varieties and experimental lines. The profiles included free, soluble-conjugated, and insoluble-bound forms of total phenolics, flavonoids, and ferulic acids and carotenoid content including lutein, zeaxanthin, and beta-cryptoxanthin. The results showed that total phenolic content (709.8-860.0 micromol of gallic acid equiv/100 g of wheat), total antioxidant activity (37.6-46.4 micromol of vitamin C/g), and total flavonoid content (105.8-141.8 micromol of catechin equiv/100 g of wheat) did not vary greatly among the 11 wheat lines. However, significant differences in total ferulic acid content (p < 0.05) and carotenoid content (p < 0.05) among the varieties were observed, with carotenoid content exhibiting the greatest range of values. Carotenoid content among the 11 wheat varieties exhibited 5-fold, 3-fold, and 12-fold differences in lutein, zeaxanthin, and beta-cryptoxanthin, respectively. A synthetic wheat experimental line, W7985, gave the lowest carotenoid concentrations of any of the genotypes in this study. Such large genotypic differences in carotenoid content may open up new opportunities for breeding wheat varieties with higher nutritional value.

Antioxidants↗
PubMed2004

Phytochemicals and antioxidant properties in wheat bran.

Bran samples of seven wheat varieties from four different countries were examined and compared for their phytochemical compositions and antioxidant activities. Phenolic acid composition, tocopherol content, carotenoid profile, and total phenolic content were examined for the phytochemical composition of wheat bran, whereas the measured antioxidant activities were free radical scavenging properties against 2,2-diphenyl-1-picrylhydrazyl radical, radical cation 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, peroxide radical anion O(2)(.-), and oxygen radical and chelating capacities. The results showed that the tested wheat bran samples differed in their phytochemical compositions and antioxidant properties. Ferulic acid, with a concentration range of 99-231 microg/g, was the predominant phenolic acid in all of the tested bran samples and accounted for about 46-67% of total phenolic acids on a weight basis. The concentrations for alpha-, delta-, and gamma- tocopherols were 1.28-21.29, 0.23-7.0, and 0.92-6.90 microg/g, respectively. In addition, lutein and cryptoxanthin were detected in all of the tested bran samples with levels of 0.50-1.80 and 0.18-0.64 microg/g, respectively. Zeaxanthin was detected in the six bran samples, and the greatest zeaxanthin concentration of 2.19 microg/g was observed in the Australian general purpose wheat bran. Beta-carotene was detected in four of the tested bran samples at a range of 0.09-0.40 microg/g. These data suggest that wheat and wheat bran from different countries may differ in their potentials for serving as dietary sources of natural antioxidants.

Antioxidants↗
PubMed2006

In vitro actions on human cancer cells and the liquid chromatography-mass spectrometry/mass spectrometry fingerprint of phytochemicals in rice protein isolate.

Rice protein isolate (RPI) has been reported to reduce the incidence of 7,12-dimethylbenz[a]anthracene-induced mammary tumors in rats. To determine the potential role of phytochemicals associated with the RPI, we studied in vitro antitumor activities of an ether fraction from RPI using human tumor cell lines, including two human breast carcinoma cell lines (MDA-MB-453 and MCF-7) and two myeloma cell lines (RPMI-8226 and IM-9). Concentration-dependent antiproliferative effects of the ether fraction were observed in all cell lines using the standard 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Fraction-induced apoptosis (P < 0.05) was detected in all cell lines, and this was associated with the induction of proapoptotic bax protein and cdk inhibitors (p21) and the suppression of cdk4 and cyclin D1 activity. Liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) with both positive and negative modes was used to analyze the phytochemicals in the ether fraction from RPI. Fifty-seven phytochemicals were identified or characterized by their diagnostic fragmentation patterns and direct comparison with the authentic standards on the basis of electrospray ionization-MS/MS data. The major components bound to RPI were lysoglycerophospholipids, fatty acids, and fatty acid 3-[2-(2,3-dihydroxy-propoxycarbonyl)-2-hydroxy-ethoxy]-2-hydroxy-propyl esters.

Antineoplastic Agents, Phytogenic↗
PubMed2007

Comparison of extraction methods for the quantification of selected phytochemicals in peanuts (Arachis hypogaea).

Peanuts have been reported to contain bioactive phytochemicals, particularly isoflavones (genistein, daidzein, and biochanin A) and trans-resveratrol. Currently, limited data are available regarding the levels of these bioactive compounds in peanuts with variations in reported levels. The purpose of this study was to compare four methods of extraction [stirring, sonication, Soxtec, and microwave-assisted sonication (MAS)] for runner peanuts. Quantification of the selected compounds was conducted by reverse-phase high-performance liquid chromatography (RP-HPLC). The results showed that the MAS and Soxtec methods extracted significantly higher amounts of the phytochemicals. Also, the defatted peanuts gave significantly higher amounts of the phytochemicals compared to the nondefatted peanuts. The high levels of the isoflavones may be attributed to heat-induced conversion of conjugate glycosides to aglycons. The MAS and Soxtec methods may be used for total isoflavone content quantitation, while sonication or stirring may be the method of choice for quantitation of isoflavone composition (aglycons and glycoside conjugates) in peanuts.

Arachis↗
PubMed1994

Antiviral assays on phytochemicals: the influence of reaction parameters.

Investigations of phytochemicals for antiviral activities are assuming greater importance; but little attention has been given to the influence of various reaction parameters. We found that the activities of several known antiviral phytochemicals were profoundly affected by the presence of serum components, but in different ways. Thus, the terthiophene, alpha-terthienyl (alpha-T), was inhibited in a concentration-dependent manner by serum. In the case of a carboxylic acid derivative of alpha-T, the compound appeared to have no antiviral activity at all in the presence of serum, yet in its absence this compound was as effective as alpha-T. In contrast the complex anthraquinone hypericin required a small amount of serum for maximal antiviral activity, although too much was inhibitory. The reactions were also strongly affected by the order of incubation of the components: virus, compound, serum, and light. The antiviral effects were not influenced significantly by temperature, in contrast to a report by other workers, provided the light exposures were controlled. These effects are significant because serum is commonly used in virus assays, and plant extracts often contain polypeptides. Furthermore, when phytochemicals are used in vivo, their effects could be modulated by components of tissues and body fluids.

3T3 Cells↗
PubMed2004

Successful use of an inhalational phytochemical to treat pulmonary tuberculosis: a case report.

Multi-drug resistant strains of tuberculosis pose a serious threat in many third- and first-world countries. The aim of this case report is to describe a potential new method for treating those with primary pulmonary tuberculosis using phytochemicals via inhalation. We report the first case of using inhaled phytochemicals in treating primary pulmonary tuberculosis. A 28-year-old female presented with symptoms suggestive of primary pulmonary tuberculosis, and she was found to be positive via chest X-ray and sputum culture. She subsequently underwent treatment with conventional DOTS treatment. Ten days post-inhalation of the phytochemical, the patient is tuberculosis negative (via sputum culture), with no clinical symptoms. This may be a potential new method and type of treatment for pulmonary tuberculosis.

Administration, Inhalation↗
PubMed2004

Use of Tween 40 and Tween 80 to deliver a mixture of phytochemicals to human colonic adenocarcinoma cell (CaCo-2) monolayers.

Epidemiological evidence suggests that dietary intake of carotenoids and tocopherols may influence the risk of certain chronic diseases, such as cancer and CVD. In vitro studies investigating the synergistic effects of mixtures of carotenoids and tocopherols have been hindered due to the difficulty of solubilising these lipophilic compounds. The objective of the present study was to develop a system for delivering tocopherols and carotenoids simultaneously to cells in culture. Differentiated human colonic adenocarcinoma cells (CaCo-2) were incubated with a mixture of these phytochemicals for 24 h. The phytochemical mixture included carotenoids (astaxanthin, canthaxanthin, lutein, lycopene, alpha-carotene, beta-carotene) and tocopherols (alpha-tocopherol and gamma-tocopherol). The emulsifiers polyoxyethylene sorbitan monopalmitate (Tween 40) and polyoxyethylene sorbitan monooleate (Tween 80) were employed as the delivery vehicles, and were compared with tetrahydrofuran (THF). Each vehicle was added at a maximum concentration of 1 ml/l. No toxic effects to the CaCo-2 cells were noted when Tween 40 or Tween 80 were used. Both Tween 40 and Tween 80 resulted in greater solubility of the mixture and delivered substantially more carotenoids and tocopherols to the cells than THF. In particular, lycopene was detected within the cells when Tween 40 and Tween 80 were employed, whereas it was below the limits of detection by HPLC when THF was used as the delivery vehicle. The phytochemicals were retained within the cells for 24 h after supplementation. Tween 40 and Tween 80 have potential as simple, rapid and non-toxic methods for delivering mixtures of carotenoids and tocopherols to cells in culture.

Antioxidants↗
PubMed2003

Herbivore responses to plant secondary compounds: a test of phytochemical coevolution theory.

Literature data were collected on the floristic distribution and toxicity of phytochemicals to herbivores and on herbivore specialization in order to test phytochemical coevolution theory. The theory makes four predictions that can be tested with this information. Herbivores can adapt to novel, more toxic chemicals by becoming specialists, or they can become generalists but at the cost of lower feeding success on any particular host. Thus, the first two predictions are as follows: herbivores should do better on chemicals that are present in their normal host, and this pattern should be stronger for specialists than for generalists. The "escape and radiation" aspect of the theory holds that if a plant taxon with a novel defense chemical diversifies, the chemical will become widespread. Eventually, herbivores will adapt to and disarm it. So the third prediction is that more widespread chemicals are less toxic than more narrowly distributed ones. Because generalists should not do as well as specialists on chemicals disarmed by the latter, the fourth prediction is that the third prediction should be more true for generalists than specialists and should depend on presence/absence of the chemical in the normal host. Multiple regressions of toxicity (herbivore mortality and final weight) on three predictor variables (chemical presence/absence in the normal host, specialism, and chemical floristic distribution) and relevant interactions were used to test these predictions. Chemical presence/absence in the normal host, the interaction between this variable and specialism, and chemical floristic distribution had significant effects on both measures of toxicity, supporting the first three predictions of the model. Support for the fourth prediction (a three-way interaction among all predictor variables) was evident for final weight but not mortality, perhaps because growth is more responsive to toxicity differences than survival. In short, the phytochemistry literature provides broad support for the phytochemical coevolution model.

Adaptation, Physiological↗
PubMed1996

Do dietary phytochemicals with cytochrome P-450 enzyme-inducing activity increase high-density-lipoprotein concentrations in humans?

Low plasma concentrations of high-density lipoprotein (HDL) are associated with increased risk of coronary heart disease. Several drugs that induce the microsomal cytochrome P-450-dependent enzyme system in liver and intestine, the sites of HDL apolipoprotein (apo) A-I and A-II synthesis, raise plasma HDL concentrations in humans. To test the hypothesis that phytochemicals with cytochrome P-450-inducing activity may also increase plasma HDL concentrations, two controlled dietary trials were undertaken in healthy nonsmoking males aged 20-28 y. One study examined the effect of replacing 300 g glucosinolate-free vegetables with 300 g Brussels sprouts/d for 3 wk. The other study examined the effects of 150 mg eugenol/d in capsule form, using a double-blind, placebo-controlled crossover design. There were no significant increases in plasma apo A-I, apo A-II, HDL cholesterol, or HDL phospholipids. These results suggest that dietary phytochemicals that induce members of the cytochrome P-450 system do not necessarily raise plasma HDL concentrations in humans, but do not exclude the possibility that some phytochemicals may have such an effect.

Adult↗
PubMed2003

Risk of human ovarian cancer is related to dietary intake of selected nutrients, phytochemicals and food groups.

Intakes of specific nutrients and food groups have been shown previously to be related to ovarian cancer risk, but no studies, to our knowledge, have emphasized the effect of phytochemical intakes on this cancer. We conducted a case-control study of diet and ovarian cancer in western New York involving 124 primary, histologically confirmed ovarian cancer cases and 696 population-based controls, frequency matched to cases on age and county of residence. Diet was assessed with a detailed food-frequency questionnaire. Nutrient and phytochemical intakes were calculated from published food composition data. The odds ratios (OR) and 95% CI for risk of ovarian cancer with each nutrient, phytochemical and food group were estimated with unconditional logistic regression adjusting for age, education, total months menstruating, difficulty becoming pregnant, oral contraceptive use, menopausal status and energy intake. Compared with women in the lowest quintile of intake, reduced risks were observed for women in the highest quintile of intake of dietary fiber (OR 0.43, 95% CI, 0.20-0.94), total carotenoids (OR 0.33, 95% CI, 0.16-0.68), stigmasterol (OR 0.42, 95% CI, 0.20-0.87), total lignans (OR 0.43, 95% CI, 0.21-0.85), vegetables (OR 0.47, 95% CI, 0.23-0.97) and poultry (OR 0.45, 95% CI, 0.22-0.92). These results support a protective effect on ovarian cancer of phytoestrogen intakes, and our results support the hypothesis that a plant-based diet may be important in reducing risks of hormone-related neoplasms.

Adult↗
PubMed2004

Tomato phytochemicals and prostate cancer risk.

Mounting evidence over the past decade suggests that the consumption of fresh and processed tomato products is associated with reduced risk of prostate cancer. The emerging hypothesis is that lycopene, the primary red carotenoid in tomatoes, may be the principle phytochemical responsible for this reduction in risk. A number of potential mechanisms by which lycopene may act have emerged, including serving as an important in vivo antioxidant, enhancing cell-to-cell communication via increasing gap junctions between cells, and modulating cell-cycle progression. Although the effect of lycopene is biologically relevant, the tomato is also an excellent source of nutrients, including folate, vitamin C, and various other carotenoids and phytochemicals, such as polyphenols, which also may be associated with lower cancer risk. Tomatoes also contain significant quantities of potassium, as well as some vitamin A and vitamin E. Our laboratory has been interested in identifying specific components or combination of components in tomatoes that are responsible for reducing prostate cancer risk. We carried out cell culture trials to evaluate the effects of tomato carotenoids and tomato polyphenols on growth of prostate cancer cells. We also evaluated the ability of freeze-dried whole-tomato powder or lycopene alone to reduce growth of prostate tumors in rats. This paper reviews the epidemiological evidence, evaluating the relationship between prostate cancer risk and tomato consumption, and presents experimental data from this and other laboratories that support the hypothesis that whole tomato and its phytochemical components reduce the risk of prostate cancer.

Animals↗