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PubMed1998

Modulation by phytochemicals of cytochrome P450-linked enzyme activity.

Compounds derived from plant sources with putative anticancer properties were studied for their effects on alkoxyresorufin O-dealkylase activity, a measure of cytochrome P450 activity. The phytochemicals investigated included benzyl isothiocyanate, caffeic acid, chlorogenic acid, diosmin, ferulic acid, indole-3-carbinol, phenethyl isothiocyanate and resveratrol. Each phytochemical at concentrations of 0.25 and 0.5 microM was incubated with 0.2 mg hamster liver microsomal protein and 0.5 microM concentrations of benzyloxyresorufin, ethoxyresorufin and methoxyresorufin. Three of the phytochemicals tested, namely benzyl isothiocyanate, phenethyl isothiocyanate and resveratrol, exhibited potent inhibition of alkoxyresorufin O-dealkylase activity. Benzyl isothiocyanate inhibited benzyloxyresorufin O-dealkylase (BROD) activity, ethoxyresorufin O-deethylase (EROD) activity and methoxyresorufin O-demethylase (MROD) activity by 90% at both the 0.25 and 0.5 microM concentrations. Phenethyl isothiocyanate inhibited BROD activity by 69%, EROD activity by 90% and MROD activity by 94% at both concentrations tested. Resveratrol inhibited BROD activity by 69% at the 0.25 microM concentration and by 78% at the 0.5 microM concentration. It inhibited EROD activity by 60% at the 0.25 microM concentration and by 80% at the 0.5 microM concentration. Resveratrol exhibited the greatest inhibitory action toward MROD, i.e. 76% and 84% at the two concentrations tested. Chlorogenic acid significantly affected BROD, EROD and MROD activity only at the 0.5 microM concentration inhibiting by 51%, 47% and 54%, respectively. Caffeic acid affected BROD and MROD activity at 0.5 microM only inhibiting BROD activity by 46% and MROD activity by 40%. Diosmin inhibited EROD activity by 11% at the 0.25 microM concentration and by 61% at 0.5 microM. It inhibited MROD by 47% and 54% at the two concentrations tested but did not significantly alter BROD activity. Ferulic acid significantly inhibited EROD and MROD activity at the 0.5 microM concentration by 28% and 32%, respectively. Indole-3-carbinol significantly inhibited BROD activity by 26% at 0.25 microM and by 42% at 0.5 microM. It inhibited EROD and MROD activity by 28% and 29% at 0.5 microM, respectively. The alkoxyresorufin O-dealkylase reactions are selective for various isoforms of cytochrome P450. Our results suggest that the phytochemicals we tested have varied effects on the enzymatic activity of isoforms of cytochrome P450 that dealkylate benzyloxyresorufin, methoxyresorufin and ethoxyresorufin and therefore may have varied effects on the metabolism of substrates for these isoforms.

Animals↗

PubMed2004

Production of intracellular phytochemicals in Chlorella under heterotrophic conditions.

A heterotrophic synchronous culture (HSC) of Chlorella regularis S-50, a strain with a high growth rate, and one for its mutant were established by alternately culturing for 6 h on medium containing glucose and for 3 h on medium without glucose. The changes in cellular components and respiratory activity during the course of cell cycling in the HSC were investigated. The synchronized daughter cells (small cells) produced by the HSC contained 2-3 times as much intracellular phytochemicals (carotenoids, chlorophyll, tocopherols, and others typical of green plants) as the glucose-metabolizing cells or the non-synchronous cell mass. To attain the HSC at high cell density, the effects of glucose and oxygen on growth rate, synchronous growth, and production of intracellular phytochemicals were revealed. During the increase in cell mass, when a glucose concentration of 0.5-10 g l(-1) in the culture fluid was maintained by glucose feeding, and the (Qo2)(max) in cells was kept constant by supplying oxygen, cell mass increased synchronously with a specific growth rate, mu, of over 0.2 h(-1). In the HSC, when the late glucose-metabolizing cells were aerated by supplying oxygen to maintain over a half of the (Qo2)(max) under glucose-deficient conditions, intracellular phytochemicals increased rapidly in parallel with cell division. On the basis of these results, the HSC system at high cell density was attained by a glucose-limited fed-batch culture that involves three controlled conditions; glucose concentration, glucose feeding time, and oxygen supply. The system maintained synchronous growth for more than three generations until the cell density reached about 90 g l(-1) with a mu of 0.2 h(-1). In the HSC system, synchronized daughter cells were obtained at a cell productivity of 84 g l(-1) (30 h)(-1). The cell yield for glucose was 0.45. A weight of 100 g of dry cells contained 710 mg carotenoids, 350 mg lutein, 50 mg alpha-carotene, 60 mg beta-carotene, 3.3 g chlorophylls, 23 mg tocopherols, and others, with 63 g of protein rich in essential amino acids. Industrial-scale HSC systems made it possible to steadily produce Chlorella, containing 10-50 times as much phytochemicals as green and yellow vegetables, regardless of the weather.

Journal Article↗

PubMed2004

Improved fractionation of glycinin and beta-conglycinin and partitioning of phytochemicals.

Glycinin-rich and beta-conglycinin-rich products are prepared by soy protein fractionation. Physicochemical characteristics of these proteins affect their unique, important functionality in food systems and industrial applications. Soybean isoflavones and saponins are phytochemicals with potential health benefits. Objectives of this protein fractionation research were to (1) improve protein and phytochemical extraction from defatted soy flakes and recovery in product fractions and (2) evaluate phytochemical partitioning and profile changes during fractionation. Extraction environments (pH, ethanol concentration, temperature, and water-to-flake ratio) were each varied during bench-scale optimization. Optimized conditions of 45 degrees C and 10:1 water-to-flake ratio were compared with previous conditions of 20 degrees C and 15:1 water-to-flake ratio and a soy protein isolate process at pilot scale. Optimized conditions yielded more beta-conglycinin with higher isoflavone and saponin concentrations, but fraction purity was diminished by glycinin contamination. Bench-scale data demonstrated that increased phytochemical extraction did not translate into increased concentrations in product fractions.

Antigens, Plant↗

PubMed2005

Phytochemicals and antioxidant activity of milled fractions of different wheat varieties.

The health-promoting effects of whole-grain consumption have been attributed in part to their unique phytochemical contents and profiles that complement those found in fruits and vegetables. Wheat is an important component of the human diet; however, little is known about the phytochemical profiles and total antioxidant activities of milled fractions of different wheat varieties. The objectives of this study were to investigate the distribution of phytochemicals (total phenolics, flavonoids, ferulic acid, and carotenoids) and to determine hydrophilic and lipophilic antioxidant activity in milled fractions (endosperm and bran/germ) of three different wheat varieties, two of which were grown in two environments. Grain samples of each of the wheat varieties were milled into endosperm and bran/germ fractions. Each fraction was extracted and analyzed for total phenolics, ferulic acid, flavonoids, carotenoid contents, and hydrophilic and lipophilic antioxidant activities. Total phenolic content of bran/germ fractions (2867-3120 micromol of gallic acid equiv/100 g) was 15-18-fold higher (p < 0.01) than that of respective endosperm fractions. Ferulic acid content ranged from 1005 to 1130 micromol/100 g in bran/germ fractions and from 15 to 21 micromol/100 g in the endosperm fractions. The bran/germ fraction flavonoid content was 740-940 micromol of catechin equiv/100 g. On average, bran/germ fractions of wheat had 4-fold more lutein, 12-fold more zeaxanthin, and 2-fold more beta-cryptoxanthin than the endosperm fractions. Hydrophilic antioxidant activity of bran/germ samples (7.1-16.4 micromol of vitamin C equiv/g) was 13-27-fold higher than that of the respective endosperm samples. Similarly, lipophilic antioxidant activity was 28-89-fold higher in the bran/germ fractions (1785-4669 nmol of vitamin E equiv/g). Hydrophilic antioxidant activity contribution to the total antioxidant activity (hydrophilic + lipophilic) was >80%. In whole-wheat flour, the bran/germ fraction contributed 83% of the total phenolic content, 79% of the total flavonoid content, 51% of the total lutein, 78% of the total zeaxanthin, 42% of the total beta-cryptoxanthin, 85% of the total hydrophilic antioxidant activity, and 94% of the total lipophilic antioxidant activity. Our results showed that different milled fractions of wheat have different profiles of both hydrophilic and lipophilic phytochemicals. These findings provide information necessary for evaluating contributions to good health and disease prevention from whole-wheat consumption.

Antioxidants↗

PubMed2000

Phytochemicals and the breakthrough of traditional herbs in the management of sexual dysfunctions.

Traditional herbs have been a revolutionary breakthrough in the management of erectile dysfunction and have become known world-wide as an 'instant' treatment. The modern view of the management of erectile dysfunction subscribes to a single etiology, i.e. the mechanism of erection. A large number of pharmacological agents are orally consumed and vasoactive agents inserted intraurethrally or injected intrapenially to regain good erection. Modern phytochemicals have developed from traditional herbs. Phytochemicals focus their mechanism of healing action to the root cause, i.e. the inability to control the proper function of the whole body system. Hence phytochemicals manage erectile dysfunction in the frame of sexual dysfunction as a whole entity. Protodioscin is a phytochemical agent derived from Tribulus terrestris L plant, which has been clinically proven to improve sexual desire and enhance erection via the conversion of protodioscine to DHEA (De-Hydro-Epi-Androsterone). Preliminary observations suggest that Tribulus terrestris L grown on different soils does not consistently produce the active component Protodioscin. Further photochemical studies of many other herbal plants are needed to explain the inconsistent results found with other herbal plants, such as in diversities of Ginseng, Eurycoma longifolia, Pimpinella pruacen, Muara puama, Ginkgo biloba, Yohimbe etc.

Clinical Trials as Topic↗

PubMed2004

Vitamins, phytochemicals, diets, and their implementation in cancer chemoprevention.

With progressive "Westernization" of the dietary pattern in Asian countries, such as Korea and Japan, unhealthy signs, such as increases in obesity and incidence rate of cancers, are starting to appear in recent statistics. These results support the hypothesis that a dietary pattern of low fats and high antioxidants based on plant foods will reduce the risk of cancer Recently, antioxidative vitamins and phenolic phytochemicals derived from our daily diet have received much attention because of their potential chemopreventive activities. Their chemopreventive mechanisms have been suggested mainly due to their protective effects against oxidative DNA damage. However. several studies have shown that dietary antioxidant supplements, such as vitamins and phenolic phytochemicals, are not beneficial; they may rather, cause DNA damage. These results suggest that a metabolomics approach might demonstrate that antioxidant rich whole diets play a more important role, rather than individual antioxidants in cancer prevention. On the other hand, the chemopreventive mechanisms of dietary vitamins and phenolic phytochemicals may be associated with the inhibition of other carcinogenic processes, particularly tumor promotion, rather than that of tumor initiation. In this article, possible cancer-preventive mechanisms of dietary vitamins and phenolic phytochemicals, are reviewed.

Anti-Inflammatory Agents↗

PubMed2003

Health benefits of fruit and vegetables are from additive and synergistic combinations of phytochemicals.

Cardiovascular disease and cancer are ranked as the first and second leading causes of death in the United States and in most industrialized countries. Regular consumption of fruit and vegetables is associated with reduced risks of cancer, cardiovascular disease, stroke, Alzheimer disease, cataracts, and some of the functional declines associated with aging. Prevention is a more effective strategy than is treatment of chronic diseases. Functional foods that contain significant amounts of bioactive components may provide desirable health benefits beyond basic nutrition and play important roles in the prevention of chronic diseases. The key question is whether a purified phytochemical has the same health benefit as does the whole food or mixture of foods in which the phytochemical is present. Our group found, for example, that the vitamin C in apples with skin accounts for only 0.4% of the total antioxidant activity, suggesting that most of the antioxidant activity of fruit and vegetables may come from phenolics and flavonoids in apples. We propose that the additive and synergistic effects of phytochemicals in fruit and vegetables are responsible for their potent antioxidant and anticancer activities, and that the benefit of a diet rich in fruit and vegetables is attributed to the complex mixture of phytochemicals present in whole foods.

Adolescent↗

PubMed1997

Evaluation of the potential for olestra to affect the availability of dietary phytochemicals.

It has been hypothesized that phytochemicals found in fruits and vegetables are responsible for the inverse association observed between diets high in fruits and vegetables and risk of certain chronic diseases and cancer. This paper assesses the potential for olestra to affect the absorption of dietary phytochemicals and estimates the effect of olestra on the availability of carotenoids when olestra-containing snacks and foods containing carotenoids are eaten in free-living diets. Experimental data compiled on the effects of olestra on the availability of 29 compounds, mainly nutrients and oral medications, showed that olestra affects the availability of only molecules having octanol-water partition coefficients greater than approximately 7.5. Partition coefficients compiled for 382 dietary phytochemicals showed that only two classes of phytochemicals, phytosterols and carotenoids, contain molecules with octanol-water partition coefficients in the range in which olestra could potentially affect bioavailability. The potential effect on the bioavailability of phytosterols would be <10% and would not be expected to be of concern inasmuch as the hypothesized benefit of consuming pharmacological amounts of phytosterols is to reduce cholesterol availability, a function also of olestra. A 5.9% reduction in the average effective beta-carotene intake was calculated for individuals eating olestra-containing snack foods in free-living diets. The calculation was made by assuming that carotenoid bioavailability would be reduced to the extent measured in human clinical studies each time olestra-containing snacks and carotenoid-containing foods are eaten together and that all snacks eaten are made with olestra. Among individuals with low carotenoid intakes (the lowest 10%) the calculated reduction was 6.0%; for heavy snack eaters (the top 10%) it was 9.5%. These effects on carotenoid bioavailability are similar to those that can occur with other dietary factors.

Adolescent↗

PubMed2001

Phytochemical glyceollins, isolated from soy, mediate antihormonal effects through estrogen receptor alpha and beta.

The flavonoid family of phytochemicals, particularly those derived from soy, has received attention regarding their estrogenic activity as well as their effects on human health and disease. In addition to these flavonoids other phytochemicals, including phytostilbene, enterolactone, and lignans, possess endocrine activity. The types and amounts of these compounds in soy and other plants are controlled by both constitutive expression and stress-induced biosynthesis. The health benefits of soy-based foods may, therefore, be dependent upon the amounts of the various hormonally active phytochemicals within these foods. The aim was to identify unique soy phytochemicals that had not been previously assessed for estrogenic or antiestrogenic activity. Here we describe increased biosynthesis of the isoflavonoid phytoalexin compounds, glyceollins, in soy plants grown under stressed conditions. In contrast to the observed estrogenic effects of coumestrol, daidzein, and genistein, we observed a marked antiestrogenic effect of glyceollins on ER signaling, which correlated with a comparable suppression of 17 beta-estradiol-induced proliferation in MCF-7 cells. Further evaluation revealed greater antagonism toward ER alpha than ER beta in transiently transfected HEK 293 cells. Competition binding assays revealed a greater affinity of glyceollins for ER alpha vs. ER beta, which correlated to greater suppression of ER alpha signaling with higher concentrations of glyceollins. In conclusion, we describe the phytoalexin compounds known as glyceollins, which exhibit unique antagonistic effects on ER in both HEK 293 and MCF-7 cells. The glyceollins as well as other phytoalexin compounds may represent an important component of the health effects of soy-based foods.

Benzopyrans↗

PubMed1998

Effect of dietary phytochemicals on cancer development (review)

Vegetables, fruits, and whole grains contain a wide variety of phytochemicals that have the potential to modulate cancer development. There are many biologically plausible reasons why consumption of plant foods might slow or prevent the appearance of cancer. These include the presence in plant foods of such potentially anticarcinogenic substances as carotenoids, chlorophyll, flavonoids, indole, isothiocyanate, polyphenolic compounds, protease inhibitors, sulfides, and terpens. The specific mechanisms of action of most phytochemicals in cancer prevention are not yet clear but appear to be varied. Considering the large number and variety of dietary phytochemicals, their interactive effects on cancer risk may be extremely difficult to assess. Phytochemicals can inhibit carcinogenesis by inhibiting phase I enzymes, and induction of phase II enzymes, scavenge DNA reactive agents, suppress the abnormal proliferation of early, preneoplastic lesions, and inhibit certain properties of the cancer cell.

Animals↗

PubMed2003

[Comparative botanical and phytochemical investigations on the Gentiana species native to Hungary].

The aim of this work was to compare the three Gentiana species native to Hungary (Gentiana asclepiadea L., Gentiana pneumonanthe L. and Gentiana cruciata L.--all protected) based on their botanical and phytochemical properties. Furthermore we planned the exploration of the biodiversity of these species and the examination of the correlations of the variable elements observed to establish the importance of these factors. Morphological, histological and phytochemical investigations were made. A new analytical method was developed through the systematic optimization of sample preparation and chromatographic (HPLC-DAD) separation. The results of the morphological, histological and phytochemical investigations were analysed by multivariate exploratory techniques. Based on our results, the investigated species can be distinguished as they are strongly heterogenous regarding certain morphological, histological and phytochemical characteristics. We made the first study on the biodiversity of these Gentiana species in their whole habitat in Hungary. Based on the results of the investigations mentioned above, distinct interspecific variability was found, in addition some results showed significant intraspecific variability as well. Numerous correlations were revealed between the variable characteristics, for example significant relationship was found between the average gentiopicroside content of the underground parts of Gentiana cruciata on the biotopes and the slope of the biotope. The knowledge of this variability and these correlations can be a benefit during the introduction and the improvement of medicinal plants with high contents of agents.

Chromatography, High Pressure Liquid↗

PubMed2026

Integrated phytochemical and bioactivity profiling of Xanthium strumarium fruits from Korea and China: Implications for origin-specific quality specification.

BACKGROUND: Geographic origin influences the phytochemical composition and biological activities of medicinal plant resources. Xanthium strumarium L. (XS) fruit is widely used in East Asian traditional medicine. However, current pharmacopeial standards primarily recognize Chinese-derived material, despite the availability and traditional use of XS in Korea. To address this gap and support origin-informed quality specification, we compared fruits from Korea (XS-K) and China (XS-C) using chloroplast genome sequencing, targeted phytochemical profiling (high-performance liquid chromatography (HPLC) for selected phenolics and gas chromatography-flame ionization detection (GC-FID) for fatty acids and phytosterols, and multivariate chemometric analysis. RESULTS: Chloroplast genome analysis revealed high overall similarity but localized divergence around the rpoC2 locus and a greater mutation burden in XS-C, supporting origin-associated genomic differentiation. Phytochemical profiling revealed distinct origin-dependent metabolic signatures. XS-K showed higher levels of phytosterols, chlorogenic acid, 4,5-dicaffeoylquinic acid (4,5-DCQ), and xanthatin was detected only in XS-K, whereas XS-C exhibited greater abundance of total fatty acids, particularly oleic acid. Unsupervised clustering and log2 fold-change ranking confirmed clear compositional separation, and variable importance in projection (VIP) analysis identified chlorogenic acid, β-sitosterol, oleic acid, 4,5-DCQ, and xanthatin as major discriminators between origins. Bioactivity assays demonstrated that XS-K exerted stronger antioxidant effects in ABTS, DPPH and FRAP assays, stronger skin-related enzyme inhibition, and greater antibacterial activity against Staphylococcus aureus, consistent with its enriched phenolic and sterol profile. CONCLUSION: Together, chloroplast sequence variation, targeted metabolite quantification, and screening bioassays consistently distinguished XS-K from XS-C. These findings support the use of candidate markers for the origin-based authentication and quality control of XS fruit-derived ingredients. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Fruit↗

PubMed2007

Dietary polyphenolic phytochemicals--promising cancer chemopreventive agents in humans? A review of their clinical properties.

Epidemiological and preclinical evidence suggests that polyphenolic phytochemicals exemplified by epigallocatechin gallate from tea, curcumin from curry and soya isoflavones possess cancer chemopreventive properties. Whilst such naturally occurring polyphenols have been the subject of numerous mechanistic studies in cells, information on their clinical properties, which might help assess their promise as human cancer chemopreventive agents, is scarce. Therefore, we present a review of pilot studies and trials with a cancer chemoprevention-related rationale, in which either healthy individuals or patients with premalignant conditions or cancer received polyphenolic phytochemicals. The review identifies trial design elements specifically applicable to polyphenolic phytochemicals. The available evidence for tea polyphenols tentatively supports their advancement into phase III clinical intervention trials aimed at the prevention of progression of prostate intraepithelial neoplasia, leukoplakia or premalignant cervical disease. In the case of curcumin and soya isoflavones more studies in premalignacies seem appropriate to optimise the nature and design of suitable phase III trials. The abundance of flavonoids and related polyphenols in the plant kingdom makes it possible that several hitherto uncharacterised agents with chemopreventive efficacy are still to be identified, which may constitute attractive alternatives to currently used chemopreventive drugs.

Antineoplastic Agents, Phytogenic↗

PubMed2006

Molecular signatures of soy-derived phytochemicals in androgen-responsive prostate cancer cells: a comparison study using DNA microarray.

The present study utilized microarray technology as a tool to elucidate the molecular signatures of soy-derived phytochemicals in the human androgen-responsive prostate cancer cell line LNCaP. Global gene expression pattern analysis of LNCaP cells exposed to 0, 1, 5, or 25 microM of the soy-derived phytochemicals equol and daidzein were conducted and compared. The data were further compared with previously generated data from exposure of LNCaP cells to the same doses of genistein, a soy isoflavone. Multidimensional scaling (MDS) analyses of the expression patterns suggest that these compounds exerted differential effects on gene expression in LNCaP cells. Further examination of specific gene changes revealed that these compounds differentially modulated genes in multiple cellular pathways, including the cell-cycle pathway genes. However, the three compounds also exerted similar effect on genes belonging to several other important cellular pathways. A universal effect of the three compounds on androgen-responsive genes, IGF-1 pathway gene, and MAP kinase-related pathway gene was observed. These results provide the foundation for establishing molecular signatures for equol, daidzein, and genistein. Moreover, these results also allow for the identification of candidate mechanism(s) by which soy phytochemicals and soy may act in prostate cancer cells.

Androgens↗

PubMed1999

Phytochemicals as modulators of cancer risk.

These results, describing antitumor activity of some of the phytochemicals that have been actively studied, suggest that dietary changes could play a role in decreasing the incidence of a variety of tumors. 13C and the other compounds discussed may well be only prototypes for other as yet unexplored phytochemicals present in the diet. There have been no attempts to explore the possibilities of synergistic action among the various phytochemicals, 13C, limonene, curcumin, epigallocatechin gallate, sulforaphene, or genistein. Mixtures of these compounds might well show potency at lower doses for each of the compounds and show even greater promise than that already demonstrated.

Anticarcinogenic Agents↗

PubMed2005

Effects of dietary chemopreventive phytochemicals on P-glycoprotein function.

The effects of dietary phytochemicals on P-glycoprotein function were investigated using human multidrug-resistant carcinoma KB-C2 cells and the fluorescent P-glycoprotein substrates daunorubicin and rhodamine 123. The effects of natural chemopreventive compounds, capsaicin found in chilli peppers, curcumin in turmeric, [6]-gingerol in ginger, resveratrol in grapes, sulforaphane in broccoli, 6-methylsulfinyl hexyl isothiocyanate (6-HITC) in Japanese horseradish wasabi, indole-3-carbinol (I3C) in cabbage, and diallyl sulfide and diallyl trisulfide in garlic, were examined. The accumulation of daunorubicin in KB-C2 cells increased in the presence of capsaicin, curcumin, [6]-gingerol, and resveratrol in a concentration-dependent manner. The accumulation of rhodamine 123 in KB-C2 cells was also increased, and the efflux of rhodamine 123 from KB-C2 cells was decreased by these phytochemicals. Sulforaphane, 6-HITC, I3C, and diallyl sulfide and diallyl trisulfide had no effect. These results suggest that dietary phytochemicals, such as capsaicin, curcumin, [6]-gingerol, and resveratrol, have inhibitory effects on P-glycoprotein and potencies to cause drug-food interactions.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2005

Comparative molecular and phytochemical investigation of Leontodon autumnalis (Asteraceae, Lactuceae) populations from Central Europe.

Previous analyses of Leontodon autumnalis L. revealed the existence of two chemotypes. In the current study molecular and phytochemical methods were combined to investigate 24 Central European populations of L. autumnalis. The focus of this study was the correlation of molecular and phytochemical characters at the intraspecific level. DNA fingerprint profiles of 183 individuals were obtained by random amplified polymorphic DNA (RAPD) providing 77 molecular markers. Contents of phenolics and sesquiterpenoids of flowering heads and sub-aerial parts were quantified by HPLC-DAD analyses. HPLC results were evaluated by principal component analysis. Geographic distribution of the two detected chemotypes partially overlapped. Phylogenetic groupings displayed in an unrooted neighbor-joining tree calculated from the RAPD data matrix were correlated with the geographical origin of the plant material. However, genetic profiles neither correlated with the two chemotypes nor with the morphologically based subspecies of L. autumnalis recognized by some authors. The presented data imply that the morphotypes are of multiple origins or due to different ecological growing conditions rather than genetically determined and that phytochemical races are induced by a limited number of genetical differences, which might have occurred independently in different lineages of the L. autumnalis group.

Asteraceae↗

PubMed2006

Neurohormetic phytochemicals: Low-dose toxins that induce adaptive neuronal stress responses.

Diets rich in vegetables and fruits are associated with reduced risk of several major diseases, including neurodegenerative disorders. Although some beneficial phytochemicals might function solely as antioxidants, it is becoming clear that many of the beneficial chemicals in vegetables and fruits evolved as toxins (to dissuade insects and other predators) that, at subtoxic doses, activate adaptive cellular stress-response pathways in a variety of cells including neurons. Examples of such 'preconditioning' or 'neurohormesis' pathways include those involving cell-survival signaling kinases, the transcription factors NRF2 and CREB, and histone deacetylases of the sirtuin family. In these ways, neurohormetic phytochemicals such as resveratrol, sulforaphanes and curcumin might protect neurons against injury and disease by stimulating the production of antioxidant enzymes, neurotrophic factors, protein chaperones and other proteins that help cells to withstand stress. Thus, as we discuss in this review, highly conserved longevity and survival pathways in neurons are the targets of many phytochemicals.

Animals↗