Wilhelm Stahl

• Professor
• Heinrich Heine University Düsseldorf

Elevated serum cholesterol concentrations in mid-life increase risk for Alzheimer's disease (AD) in later life. However, lower concentrations of cholesterol-carrying high density lipoprotein (HDL) and its principal apolipoprotein A1 (ApoA1) correlate with increased risk for AD. As HDL transports oxocarotenoids, which are scavengers of peroxynitrite...

Treatment of the most aggressive and deadliest form of skin cancer, the malignant melanoma, still has room for improvement. Its invasive nature and ability to rapidly metastasize and to develop resistance to standard treatment often result in a poor prognosis. While the highly effective standard chemotherapeutic agent doxorubicin (DOX) is widely us...

Background Malignant melanoma is the most aggressive form of skin cancer with a rather poor prognosis. Standard chemotherapy often results in severe side effects on normal (healthy) cells finally being difficult to tolerate for the patients. Shown by us earlier, cerium oxide nanoparticles (CNP, nanoceria) selectively killed A375 melanoma cells whil...

Despite great efforts to develop new therapeutic strategies to combat melanoma, the prognosis remains rather poor. Artesunate (ART) is an antimalarial drug displaying anti-cancer effects in vitro and in vivo. In this in vitro study, we investigated the selectivity of ART on melanoma cells. Furthermore, we aimed to further elucidate the mechanism of...

Neuroblastoma is the most common extracranial malignant tumor in childhood. Approximately 60% of all patients are classified as high-risk and require intensive treatment including non-selective chemotherapeutic agents leading to severe side effects. Recently, phytochemicals like the natural chalcone cardamonin (CD) have gained attention in cancer r...

Cutaneous basal and squamous cell carcinoma reflect the first and second most common type of non-melanoma skin cancer, respectively. Especially cutaneous squamous cell carcinoma has the tendency to metastasize, finally resulting in a rather poor prognosis. Therapeutic options comprise surgery, radiation therapy, and a systemic or targeted chemother...

Background Preventive lifestyle strategies have shown promise to slow down or prevent age-related cognitive decline. However, evidence on the reciprocal longitudinal relationships between nutrition biomarkers and cognitive and physical performance is lacking. Studying nutritional, cognitive, and physical profiles over time may help to overcome this...

Objective To investigate the association of dental and cardiac disease in a cohort of captive chimpanzees Design 12 captive chimpanzees underwent periodontal and cardiac examinations under anaesthesia during a relocation to a new enclosure. Blood samples were taken for analysis of circulating markers of cardiac health, nutritional status and isola...

Carbon monoxide (CO) is endogenously produced upon degradation of heme by heme oxygenases (HOs) and is suggested to act as a gaseous signaling molecule. The expression of HO-1 is triggered by the Nrf2-Keap1 signaling pathway which responds to exogenous stress signals and dietary constituents such as flavonoids and glucosinolates or reactive metabol...

The term „nutritional cognitive neuroscience“ was recently established to define a research field focusing on the impact of nutrition on cognition and brain health across the life span. In this overview, we summarize the robust evidence on the role of carotenoids as micronutrients with different biological properties in persons with cognitive (pre)...

A major challenge in current cancer therapy is still the treatment of metastatic melanomas of the skin. BH3 mimetics represent a novel group of substances inducing apoptosis. In this study, we investigated the cytotoxic effect of (±) gossypol (GP), a natural compound from cotton seed, on A375 melanoma cells and the underlying biochemical mechanisms...

Selenoenzymes, whose activity depends on adequate selenium (Se) supply, and phase II enzymes, encoded by target genes of nuclear factor erythroid 2-related factor 2 (Nrf2), take part in governing cellular redox homeostasis. Their interplay is still not entirely understood. Here, we exposed HepG2 hepatoma cells cultured under Se-deficient, Se-adequa...

Carbon monoxide (CO) intoxication is one of the most frequent causes of accidental poisoning, mechanistically related to the inhibition of oxygen transport following blockage of the oxygen binding site of hemoglobin. However, it has become evident that CO is also a gaseous signaling molecule like nitric oxide and capable to trigger cellular stress...

Stress-inducible heme oxygenase-1 (HO-1) catalyzes the oxidative cleavage of heme yielding biliverdin, ferrous iron, and carbon monoxide (CO). Heme oxygenase activity has been attributed to antioxidant defense via the redox cycling system of biliverdin and bilirubin. There is increasing evidence that CO is a gaseous signaling molecule and plays a r...

Intracellular carbon monoxide (CO) is a gaseous signaling molecule and is generated enzymatically by heme oxygenases upon degradation of heme to billiverdin. Target structures for intracellular produced CO are heme proteins including cytochrome c oxidase of the respiratory chain, cytochrome P450-dependent monooxygenase, or myoglobin. For studies on...

Mitochondria are important (patho)physiological sources of reactive oxygen species (ROS) that mediate mitochondrial dysfunction and phospholipid oxidation; an increase in mitochondrial content of oxidized phospholipid (OxPL) associates with cell death. Previously we showed that the circulating OxPL 1-palmitoyl-2-(5’-oxo-valeroyl)-sn-glycero-3-phosp...

Cerium (Ce) oxide nanoparticles (CNP; nanoceria) are reported to have cytotoxic effects on certain cancerous cell lines, while at the same concentration they show no cytotoxicity on normal (healthy) cells. Redox-active CNP exhibit both selective prooxidative as well as antioxidative properties. The former is proposed to be responsible for impairmen...

Light-exposed tissues are affected by photooxidative stress that causes and promotes diseases, including skin cancer and cataract and age-related macular degeneration (AMD). Nutrition supplies components for powerful enzymatic and nonenzymatic defense systems. Among the micronutrients, carotenoids and flavonoids from dietary sources have been exami...

The skin is shielding our organism from exogenous threats including solar radiation. Carotenoids which are ingested with the diet accumulate in the skin with the highest levels occurring in skin of the forehead and in the palms of the hands. Blood and skin levels of carotenoids increase during supplementation and due to their antioxidant properties...

Malignant melanoma is an aggressive type of cancer and the deadliest form of skin cancer. Even though enormous efforts have been undertaken, in particular the treatment options against the metastasizing form are challenging and the prognosis is generally poor. A novel therapeutical approach is the application of secondary plant constituents occurri...

Age-associated cognitive impairment in general and dementia in particular are a global concern. Preventive lifestyle strategies are highly used but there is a lack of information on the reciprocal relationships between nutrition biomarkers and measures of both cognitive and physical performance. To fill this gap of knowledge, the relationship betwe...

Chalcones are a type of flavonoids characterized by an α-β unsaturated structural element which may react with thiol groups to activate pathways such as the Nrf2-Keap-1 system. Naringenin chalcone is abundant in the diet but little is known about its bioavailability. In this work, the bioavailability of naringenin chalcone from tomatoes was investi...

Next to its well-studied toxicity, carbon monoxide (CO) is recognized as a signalling molecule in various cellular processes. Thus, CO-releasing molecules (CORMs) are of considerable interest for basic research and drug development. Aim of the present study was to investigate if CO, released from CORMs, inhibits cytochrome P450- dependent monooxyge...

BH3 mimetics, such as BH3I-1, act as Bcl-2 antagonists, promote apoptosis and are used in basic research studies on apoptotic signaling and are currently tested as experimental anti-tumor agents. The present study addresses time- and dose-dependent responses of BH3I-1 on apoptosis, cellular stress defense mediated by hemeoxygenase-1 (HO-1), and mit...

Introduction: During exercise in hypoxia, O2delivery to brain and muscle is compromised and oxidative stress is elicited. Cocoa flavanols (CF) have antioxidant capacities and can increase blood flow by stimulating endothelial function. We aimed to examine the effects of 7-day CF intake on oxidative stress, nitric oxide production and tissue oxygen...

Background Cocoa flavanols (CF) can stimulate vasodilation by improved nitric oxide (NO) synthesis and have antioxidant and anti-inflammatory capacities. This study aimed to examine whether acute CF intake can affect exercise-induced changes in antioxidant capacity, oxidative stress, inflammation and NO production, as well as exercise performance a...

The biomedical application of cerium oxide nanoparticles (nanoceria) is a focal point of research for a few years. The biochemical effects of nanoceria depend on various factors including particle size, oxidation state of cerium, oxygen vacancies on the surface, use of dispersants or coatings, pH and cell type. Due to their autocatalytic redox-acti...

Background & aims: Surgical trauma leads to an inflammatory response that causes surgical morbidity. Reduced antioxidant micronutrient (AM)(a) levels and/or excessive levels of Reactive Oxygen Species (ROS)(b) have previously been linked to delayed wound healing and presence of chronic wounds. We aimed to evaluate the effect of pre-operative suppl...

Background: Increasing evidence suggests photoprotection by oral supplementation with β-carotene and lycopene. Objectives: To examine the capacity of lycopene-rich tomato nutrient complex (TNC) and lutein, to protect against ultraviolet (UV)A/B and UVA1 radiation at a molecular level. Methods: In a placebo-controlled, double-blinded, randomize...

Carotenoid dietary intake and their endogenous levels have been associated with a decreased risk of several chronic diseases. There are indications that carotenoid bioavailability depends, in addition to the food matrix, on host factors. These include diseases (e.g. colitis), life-style habits (e.g. smoking), gender and age, as well as genetic vari...

Dietary antioxidants, their biological effects and underlying mechanisms of action are key topics of research at the Institute of Biochemistry and Molecular Biology I at the Heinrich-Heine University in Düsseldorf where Helmut Sies is active now since more than 35 years. In the present article his research activity on carotenoids is summarized incl...

Alzheimer's disease (AD) is not curable and is not being easily diagnosed in its preclinical phase. The present work aims at highlighting the complex though promising rationale for the maintenance of an optimal carotenoid status for the prevention of age-related cognitive impairment and its progression. The main known biological effects of caroteno...

Selenoenzymes and nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated phase II enzymes comprise key components of the cellular redox and antioxidant systems, which show multiple interrelations. Deficiency of the micronutrient selenium (Se) and impaired biosynthesis of selenoproteins have been reported to result in induction of Nrf2 target...

Patients with cystic fibrosis (CF) show decreased plasma concentrations of antioxidants due to malabsorption of lipid soluble vitamins and consumption by chronic pulmonary inflammation. β-Carotene is a major source of retinol and therefore is of particular significance in CF. The aim of this study was to investigate the effect of daily intake of re...

Carotenoid composition of crude red palm oil (Choo YM et al., Journal of the American Oil Chemists' Society, 1996)

Large-scale studies on health benefits of antioxidant supplements have failed to provide evidence for health-promoting effects of supplementation with high doses of antioxidants. This chapter explains the basic concept underlying antioxidant intervention trials, followed by a discussion of the interpretation of the results. Finally, the impact of t...

Einleitung Vorkommen von Vitamin A und Carotinoiden in Lebensmitteln Analytik und Gehalte von Vitamin A und Carotinoiden in Lebensmitteln Aufnahme, Verteilung, Metabolismus und Elimination von Carotinoiden und Vitamin A Wirkungen Bewertung des Gefährdungspotenzials Grenzwerte, Richtwerte, Empfehlungen, gesetzliche Regelungeng Vorsorgemaßnahmen Zusa...

Abstract 1. Chalcones are structural analogues of benzalacetophenone (BAP). Several derivatives have been identified in plants and anticarcinogenic and anti-inflammatory properties were attributed to the compounds, probably related to their direct antioxidant activity or stimulatory effects on the expression of endogenous defence enzymes like hemeo...

Protection against skin damage from sunlight by nutritional means has been examined. Likewise, there has been work on the topical application of phytochemicals to the skin. This review focuses on the nutritional aspect of phytochemicals in humans-ie, the provision of carotenoid micronutrients by dietary means to the skin and their role in protectio...

Carotenoids and flavonoids represent two classes of natural antioxidants, a biological activity, which is determined by their chemical structure. To combine their antioxidant properties, a dual functional carotenylflavonoid hybrid molecule was synthesized. The antioxidant activity of this compound was tested in human dermal fibroblasts exposed to U...

Skin cancer is among the most frequent neoplastic malignancies and exposure to UV irradiation is a major risk factor. In addition to topical sunscreens, photoprotection by dietary antioxidants such as carotenoids or polyphenols has been suggested as a means of prevention. Isorenieratene (IR) and dihydroxyisorenieratene (DHIR) are aromatic carotenoi...

Criteria for assessing the purported protection by flavanol-rich foods against vascular dysfunction and oxidative damage to biomolecules was the subject of the 27th Hohenheim Consensus Conference held on July 11, 2011. State-of-the-art evidence was put into perspective, focusing on several questions that were followed by a consensus answer. Among t...

Cognitive impairment is a common age-related disorder which affects in the stadium and type Alzheimer's Disease (AD) a steadily growing number of patients. AD is not curable and is not being easily diagnosed in its preclinical phase. This work aims at highlighting the complex though promising rationale for the use of selected micronutrients against...

Carotenoids are micronutrients present mainly in fruits and vegetables, and they are ingested from these sources with the diet. They exhibit specific antioxidant activity but also influence signaling and gene expression at the cellular level. β-Carotene and lycopene, the colorants of carrots and tomatoes, respectively, are among the most prominent...

In a recent study 60 female volunteers (40-65 years) were randomly distributed into an intervention or control group (13). Over a period of 12 weeks the participants consumed a beverage with green tea polyphenols, providing 1402 mg total catechins/day or a matched control beverage. Photoprotection, skin structure and function were measured at basel...

Oxidative stress was originally defined as a disturbance in the equilibrium between pro-oxidants and anti-oxidants. Reactive oxygen species are intercepted by the antioxidative defence system, including antioxidants in food. Thus the antioxidant defence system can be enhanced by consuming foods containing antioxidants - either at high levels or at...

Dietary constituents including polyphenols and carotenoids contribute to endogenous photoprotection and modulate skin characteristics related to structure and function of the tissue. Animal and in-vitro studies indicate that green tea polyphenols affect skin properties. In a 12-wk, double-blind, placebo-controlled study, 60 female volunteers were r...

Tumor-stroma interaction plays an important role in tumor progression. Myofibroblasts, pivotal for tumor progression, populate the microecosystem of reactive stroma. The formation of myofibroblasts is mediated by tumor derived transforming growth factor β1 (TGFβ1) which initiates a reactive oxygen species cell type dependent expression of alpha-smo...

Die Haut ist Zielorgan zahlreicher funktioneller Nahrungsmittel und -erganzungsmittel, die u. a. sekundare Pflanzenstoffe als Wirkprinzip enthalten. Am Beispiel der Kakaoflavanole und des Karotinoids Lykopin wurde untersucht, ob die Aussagen objektiven wissenschaftlichen Messmethoden standhalten. In einer Interventionsstudie erwiesen sich Kakaoflav...

The dietary flavanol (-)-epicatechin has been suggested to mediate its vasodilatory effect by increasing nitric oxide levels in endothelial cells. To directly prove the formation of nitric oxide (NO) in human endothelial cells (HUVEC) in vitro by trapping NO to yield a fluorescent nitrosamine. HUVEC were treated with (-)-epicatechin; nitrite and NO...

Flavonoids are a group of widespread plant constituents available from dietary sources such as cocoa, green tea, soy, berries, or other fruits like apples, lemons, cherries, plums, and peaches. There is evidence that flavonoid-rich products contribute to the protection of skin against UV-induced damage at the molecular and cellular level and that t...

Carotenoids are micronutrients present in fruits and vegetables and ingested with the diet. They exhibit specific antioxidant activity and also influence cellular signaling and gene expression at the cellular level. b-Carotene and lycopene, the colorants of carrots respectively tomatoes, are among the most prominent members of this group and the do...

Dietary antioxidants may play a role in the prevention of oxidative damage related to the risk for several diseases. There are various approaches to substantiate claims on food products containing antioxidants. Claims concerning bioavailability are often linked to specific processing or fortification, providing higher amounts of the antioxidant cir...

Experts in the field of carotenoids met at the Hohenheim consensus conference in July 2009 to elucidate the current status of β-carotene research and to summarize the current knowledge with respect to the chemical properties, physiological function, and intake of β-carotene. The experts discussed 17 questions and reached an agreement formulated in...

A combined study of the quinoid carotenoid DHIRQ by femtosecond transient absorption spectroscopy and quantum chemical calculations revealed its very complex electronic structure and ultrafast relaxation dynamics. The two quinoid end rings are found to cause a strong bathochromic shift of the absorption spectrum and to decrease the main relaxation...

Carotenoids are secondary plant constituents and more than 700 different compounds have been identified. They are synthesized by plants, where they serve as colorants for fruits and leaves, bacteria, fungi and algae. In nature carotenoids are important biological compounds due to their provitamin A activity, antioxidant properties and accessory fun...

3,3'-Dihydroxyisorenieratene (DHIR) is a structurally unusual carotenoid exhibiting bifunctional antioxidant properties. It is synthesized by Brevibacterium linens, used in dairy industry for the production of red smear cheeses. The compound protects cellular structures against photo-oxidative damage and inhibits the UV-dependent formation of thymi...

Selected biological effects of 1,4-naphthoquinone, menadione (2-methyl-1,4-naphthoquinone) and structurally related quinones from natural sources--the 5-hydroxy-naphthoquinones juglone, plumbagin and the 2-hydroxy-naphthoquinones lawsone and lapachol--were studied in human keratinocytes (HaCaT). 1,4-naphthoquinone and menadione as well as juglone a...

A higher daily intake of fruits and vegetables in healthy elderly is associated with an improved antioxidant status in comparison to subjects consuming diets poor in fruits and vegetables, but the impact on cognitive performance is unclear. Healthy community dwellers (45 to 102 years old, n=193) underwent cognitive testing and blood withdrawal for...

IntroductionCarotenoids – Biochemical Propertiesβ-Carotene – Cancer PreventionLycopene – Cancer PreventionOther Carotenoids – Cancer PreventionRetinoids – Biological PropertiesRetinoids – Cancer PreventionReferences

To explore the effects of increasing fruit and vegetable intake and the resulting effects on levels of circulating micronutrients in a community-dwelling population with an already high consumption of fruits and vegetables, 112 volunteers (86% women) underwent targeted dietary counseling for three months. At the beginning of the study and after 4,...

For the natural carotenoid 3,3'-dihydroxyisorenieratene (DHIR) and two synthetic derivatives, 3,3'-dihydroxy-16,17,18,16',17',18'-hexanor-Phi,Phi-carotene (DHHC) and Phi,Phi-carotene-3,3'-dione (DHIRQ, isorenieratene-3,3'-dione), steady state absorption experiments and combined density functional and multi-reference configuration interaction calcul...

Eine farbgebende Komponente von Rotschimmelkäse ist das bakterielle Carotinoid 3,3′-Dihydroxyisorenieratin (1). Nun ist es gelungen, 1 sowie dessen Oxidationsprodukt 2 zu synthetisieren; beide Verbindungen haben außergewöhnliche Strukturen mit phenolischen bzw. chinoiden Endgruppen. Anhand von acht Modellsystemen wurden die antioxidativen und photo...

(Figure Presented) The color of red smear cheeses arises from naturally occurring carotenoids like 3,3′-dihydroxyisorenieratene (1). This compound and its oxidation product 2, which have unusual phenolic and quinoid end groups, respectively, were synthesized. The antioxidant and photoprotective properties of a series of carotenoids were tested with...

(Figure Presented) The color of red smear cheeses arises from naturally occurring carotenoids like 3,3′-dihydroxyisorenieratene (1). This compound and its oxidation product 2, which have unusual phenolic and quinoid end groups, respectively, were synthesized. The antioxidant and photoprotective properties of a series of carotenoids were tested with...

Rotschimmelkase wie der im Bild gezeigte erhalt seine Farbe durch Bakterien wie Brevibacterium linens, die hocheffiziente antioxidative und photoprotektive phenolische Carotinoide, z. B. 3,3′-Dihydroxyisorenieratin (DHIR), enthalten. H.-D. Martin, W. Stahl et al. beschreiben in der Zuschrift auf S. 406 ff. die Synthese von DHIR sowie die Untersuchu...

Carotenoids are used for systemic photoprotection in humans. Regarding mechanisms underlying photoprotective effects of carotenoids, here we compared the modulation of UVA-related injury by carotenoids. Human dermal fibroblasts (HDF) were exposed to moderate doses of UVA, which stimulated apoptosis, increased levels of reactive oxygen species and t...

Ingestion of selected nutrients modulates dermal properties. In the present study, two groups of women ingested flaxseed or borage oil for 12 weeks. The control group received a placebo containing medium-chain fatty acids. Dose was 2.2 g total fatty acids/d with alpha-linolenic acid and linoleic acid as major constituents in the flaxseed oil group;...

Die menschliche Haut wird kontinuierlich internen und externen Einflüssen ausgesetzt, die ihren Zustand und ihre Funktion verändern können. Biologische Konsequenzen, die sich hieraus ergeben können, sind Alterungsprozesse, Entzündungen, immunologische Dysfunktionen, eine Störung der epidermalen Homeostase und eine Vielzahl weiterer Hauterkrankungen...

The concept of photoprotection by dietary means is gaining momentum. Plant constituents such as carotenoids and flavonoids are involved in protection against excess light in plants and contribute to the prevention of UV damage in humans. As micronutrients, they are ingested with the diet and are distributed into light-exposed tissues, such as skin...

The increase in average life expectancy In developed countries is correlated with an increasing prevalence of illnesses associated with high disability and mortality rates, such as cardiovascular disease and dementia. In addition to the interest in the potential causative role of oxidative stress in the pathophysiology of several age-related proces...

Lipid peroxidation plays an important role in the development of atherosclerosis, a chronic, age-related disease process of the arterial wall with onset decades prior to its clinical manifestations. The aim of the study was to assess the association between the intima media thickness (IMT) of the major arteries as a clinical marker of atheroscleros...

S-nitrosothiols are thought to be important intermediates in nitric oxide signaling pathways. These compounds are unstable, in part, through their ability to donate NO. One model S-nitrosothiol, S-nitrosocysteine, is particularly unstable. Recently, it was proposed that this compound decomposed via intra and intermolecular transfer of the NO group...

Exposure of living organisms to UV light leads to photooxidative reactions. Peroxyl radicals are involved in the propagation of lipid peroxidation. Carotenoids are dietary antioxidants and show photoprotective effects in human skin, efficiently scavenging peroxyl radicals and inhibiting lipid peroxidation. Cultured human skin fibroblasts were used...

Long term cocoa ingestion leads to an increased resistance against UV-induced erythema and a lowered transepidermal water loss. To investigate the acute effects of a single dose of cocoa rich in flavanols on dermal microcirculation. In a crossover design study, 10 healthy women ingested a cocoa drink (100 ml) with high (329 mg) or low (27 mg) conte...

The presence and activity of vitamin E in the organism as well as its role in disease prevention depend, as for any other microconstituent in food, on a number of factors related to its release from the food matrix, extent of absorption, and metabolic fate. Biotransformation can be defined as the sum of processes in which vitamin E compounds are al...

We report here on the synthesis and antioxidant properties of novel covalently linked flavonoid-carotenoid hybrids, hereinafter referred to as carotenylflavonoids. By this strategy the essential properties of the protecting systems are improved. Compared with the parent carotenoids or fla-vonoids, e.g. ß-carotene and a hydroxyflavone, these molecul...

Dietary antioxidants contribute to endogenous photoprotection and are important for the maintenance of skin health. In the present study, 2 groups of women consumed either a high flavanol (326 mg/d) or low flavanol (27 mg/d) cocoa powder dissolved in 100 mL water for 12 wk. Epicatechin (61 mg/d) and catechin (20 mg/d) were the major flavanol monome...

Background: Hyperhomocysteinemia is an independent risk factor associated with an increased risk for cardiovascular diseases. Vitamins B 6, B 12, and folate play a key role in the metabolism of homocysteine and it was shown that homocysteine levels decrease after oral application of a suitable vitamin supplement. Aim and study design: To decrease h...

Plant constituents such as carotenoids and flavonoids are involved in the light-protecting system in plants and contribute to the prevention of UV damage in humans. As micronutrients they are ingested with the diet and are distributed into light-exposed tissues where they provide systemic photoprotection. beta-Carotene is an endogenous photoprotect...

Previous epidemiological studies conducted in retinol-supplemented subjects showed an association between high serum levels or dietary intake of retinol and risk of hip fracture. On the other side, observational studies revealed that non-supplemented subjects with higher dietary intake of retinol lose less bone with age than subjects with lower int...

The human organism depends on an adequate energy supply provided by major dietary components, protein, carbohydrates and lipids. However, minor constituents such as vitamins, minerals and specific fatty acids are required in a healthy diet as well. Secondary plant compounds are ingested with food and enter the systemic circulation. These are not es...

Previous studies indicate that regular consumption of a diet rich in fruits and vegetables is associated with a lower risk for age-related diseases. The aim of the present study was to evaluate whether the often-reported age-related decrease of plasma antioxidants in man depends on differences in dietary intake or on other age- and gender-related f...

Astaxanthin is a carotenoid found in plants and algae; it provides the color of marine seafood such as salmon, lobster, or shrimp. Carotenoids are antioxidants and exhibit other biological functions, including effects on gap junctional communication important for homeostasis, growth control, and development of cells. Cancer cells have an impaired g...

Carotenoids comprise a class of natural fat-soluble pigments which are found in numerous fruits and vegetables. The consumption of a diet rich in carotenoids has been epidemiologically correlated with a lower risk for several diseases. The antioxidant activity of carotenoids and biochemical properties influencing signaling pathways have been discus...

Nutritional, or dietary oxidative stress denotes a disturbance of the redox state resulting from excess oxidative load or from inadequate nutrient supply favoring prooxidant reactions. Low intake or impaired availability of dietary antioxidants including vitamins E and C, carotenoids, polyphenols, and other micronutrients (e.g., selenium) weakens t...