12 Healthy Foods High in Antioxidants

Plant Phenolics as Antioxidants

Teas would not be much good without natural phenolics, and volumes have been written about the antioxidant properties of phenolics in teas, grapes (especially the skins), cranberries, and blueberries, and vegetables such as broccoli, onions, spinach, and kale. Dietary supplements of plant-derived phenolics are prevalent, and reported to function at least in part as antioxidants. In this capacity, they are presumed to react with, and deactivate, free radicals (a molecule containing an unpaired electron). Free radicals can cause cellular damage by oxidizing lipid, protein, and nucleic acids. Thus, the neutralization of free radicals by natural phenolics that have antioxidant properties is presumed to be the molecular basis for at least some of their health benefits. Turmeric (ginger family) is widely used as a spice in curries and contains large quantities of the phenolic, curcumin. Curcumin has antitumor, antioxidant, anti-amyloid, and anti-inflammatory properties. Curcumin and its...

Principal Types of Adjustments Plant Form Function and Lifecycle Acclimation

Cuticle layer, in epidermal hairs, and in epidermal cell walls as a screen against the damaging effects of ultraviolet radiation) is strongly upregulated in response to the blue and ultraviolet portions of sunlight. A subset of flavonoids, the red blue purple anthocyanins, is upregu-lated and accumulates in the epidermis of leaves under a variety of conditions, depending on the plant species. Irrespective of their specific roles (suggestions include functions as a screen against intense sunlight, as powerful antioxidants, as a sink for excess carbon, as a visual cue to attract pollinators or seed distributors), anthocyanins are highly responsive to environmental conditions and are expressed most strongly under high light. In some plant species, anthocyanins accumulate in leaves during the early phase of expansion (prior to developing photo-synthetic competence), in others during the flowering phase, and in many species they accumulate during the senescent phase of their lifespan prior...

Oxidative Stress and Redox Signaling as Common Denominators in Stress Perception and Response

While signaling pathways involving plant hormones have been studied for a long time, it has only recently been recognized that a common factor interacts or cross-talks with a multitude of other signaling pathways. This common and central factor is the cellular redox homeostasis (or balance between oxidants and antioxidants) that is affected by both internal and environmental events. A common response to a host of different types of adverse environmental conditions is an increased internal production of potentially destructive oxidants (ROS), resulting in oxidative stress. These ROS arise through interaction of oxygen with the electron-transport chains of both respiration in the mitochondria and photosynthesis in the chloroplast, as well as during plant defense against invaders. The downregulation of photosynthesis in response to stress mentioned above has a role in minimizing the generation of these ROS. In addition, ROS are formed by the light-absorbing, photosynthetic pigments...

Organisms are not fridges

Ask a friend or colleague why organisms age, and he or she will probably say something like 'inevitable wear and tear'. Indeed, there are plenty of candidate environmental agents to choose from, ranging from the physical to the chemical. For example, the wings of many damselflies and dragonflies become more tattered as they age, and the mating rates of male damselflies in the field have been found to decline after a few days.6 Similarly, reactive oxygen species (ROS), otherwise known as free radicals, are generated as by-products of a cell's metabolism and they are widely considered bad news for bodily function they can damage proteins, lipids, and DNA.7,8 Paralleling the tatter of damselfly wings, the cells of older organisms, from houseflies to humans, carry an increased concentration of oxidatively damaged compounds (including nucleic acids, lipids, and proteins), particularly in the last third of the organism's maximal lifespan.9 Could accumulated damage from life's physical and...

Toxicity Enhancement with Cu2

Copper ions are widely distributed in the natural environments and serve as metal element prerequisite for the growth of most of plants and animals. In marine environments, however, the level of concentrations of Cu2+ have been detected as a complex with various kinds of chemicals. Cu2+ in most of organisms is little accumulated due to its nonlipophilicity, but suppression of mitosis through glutathione reduction and breakage of the cellular defense against oxygen-free radicals might be brought about, probably due to the passive diffusion of Cu2+ into the cells. The most bioavailable and toxic form of unbounded Cu2+ is thought to be the free hydrated ion form, Cu(H2O)6+. Chemical form of ionic copper is governed by external pH, salinity, and concentration levels of dissolved organic matter. Thus, the toxicity of Cu2+ to bacteria also depends on not only the individual species but also the physiological and environmental conditions. The mechanism of toxicity enhancement might be...

Food componentEnergy kcalg

Vitamin A, a major constituent of visual pigments, can be obtained from carotene in plants. Vitamin D is needed for calcium transport and the prevention of rickets. Vitamin E is an antioxidant needed in many metabolic pathways. It is high in green plants and seeds, but decreases as the plants mature. Vitamin K is needed to make proteins for blood clotting. Deficiencies are unlikely to occur because it is common in all foods. The vitamin K antagonist, warfarin, causes hemorrhaging. It is used as a rodenticide.

Anthropogenic extinction See extinction

Antioxidant A compound that prevents or delays the oxidation of other compounds. Industrial antioxidants include vegetable oils and phenol derivatives used to reduce the speed of drying of paints or delay the oxidation of plastics, rubbers, drugs, and other synthetic substances as well as foodstuffs.

Plant Chemical Defenses

Photooxidants, such as the quinones (Fig. 3.3) and furanocoumarins, increase epidermal sensitivity to solar radiation. Assimilation of these compounds can result in severe sunburn, necrosis of the skin, and other epidermal damage on exposure to sunlight. Feeding on furanocoumarin-producing plants in daylight can cause 100 mortality to insects, whereas feeding in the dark causes only 60 mortality. Insect herbivores can circumvent this defense by becoming leaf rollers or nocturnal feeders (Harborne 1994) or by sequestering antioxidants (Blum 1992).

Copper Requirements and Deficiencies

C oxidase, dopamine ft hydroxylase, methane mono-oxygenase, N2O reductase, nitrite reductase, tyrosinase, ubiquinone oxidase, and phytocyanin. Copper even forms the basis of a respiratory oxygen carrier protein, hemocyanin, in crustaceans, analogous to hemoglobin in vertebrates. As is apparent from this list, copper is an important mediator in a wide variety of biological functions, including energy production, protection from free radicals, and tissue building. As a consequence organisms have evolved mechanisms for accumulating and regulating copper. A protein called Ctrl (copper permease) that helps transport copper into cells has been identified in a wide variety of organisms, from single-celled yeasts to land plants and vertebrates.

Pollution related to the most important building plastics

Polyethylene (PE) is polymerized from ethylene (ethene). Antioxidant, UV-stabilizer and pigment are added to a total of 0.5 . The antioxidant is usually a phenol compound and the ultraviolet stabilizer consists of amines or carbon black. Other additives are also used in larger or smaller proportions, such as flame retardants, mainly aluminium or magnesium hydroxide chloroparaffins can be used as well. Exposure to ethylene (ethene) may occur in the workplace. The majority of polyethylene products do not emit problematic substances in the user phase. As waste they are difficult to decompose, but can be burned for energy recovery without giving off problematic substances with the exception of carbon dioxide. Polypropylene (PP) is produced by polymerization of propylene. Ultraviolet stabilizers, antioxidants and colouring are usually added. Phenol compounds are used as antioxidants and amines as ultraviolet Antioxidants and ultraviolet stabilizers (0.02-1.8 by weight) Polystyrene (PS) is...

Competitive and Antagonistic Interactions

In this process, for example production of hydroxyl radicals by the brown-rot fungus Antrodia vaillantii increased during interaction with the bacterium Pseudomonas fluorescens (Tornberg and Olsson, 2002). Bacteria surviving in wood colonized by decay fungi must have sufficient antioxidative activity to protect themselves from being attacked by free radicals.

Reticulate evolution and essential oils

The industrial mint crops are cultivated in several countries for their essential oils. The oil, menthol, carvone, lemoline, dementholated oil and terpene fractions from the latter are variously used in the cosmetics, pharmaceuticals, food, confectionery and liquor industries (Khanuja et al. 2000). The range of medicinal applications of some mints also reflects the diversity of human-utilized products from various members of the genus Mentha. For example, extractions (containing phenols, fla-vonoids, menthol, and menthone) of the oils from peppermint (Mentha piperita) have been shown to have the potential for antimicrobial, antiviral, antioxidant, antitumor, and antiallergenic properties (McKay and Blumberg 2006). In addition, these extracts have the added benefits of (1) producing relaxation of gastrointestinal tissue, (2) analgesic and anesthetic responses in the central and peripheral nervous systems, and (3) modulating effects on the immune system of model animals (McKay and...

Exploitation of Microalgal Products

As phylogenetically the oldest organisms, microalgae have adapted to a wide range of extreme habitats. This fact has resulted in the development of numerous protective systems against various stressors - high irra diance in combination with salinity, temperature extremes, desiccation, nutrition deficiency, etc. Microalgae produce various substances such as PUFAs, lipids, antioxidants, or immunologically effective, viro static, and cytostatic compounds. Therefore, microalgae are cultivated commercially for biomass as food and feed additives, as a source of bioactive compounds for pharmacology and cosmetics, or, on a small scale, for research or diagnostic products. The biomass as a pow der, concentrated suspension, or in an applied form is the primary product. The current biotechnology appli cations of the more exploited microalgae are summarized in Table 1.

Practical Applications

Secondary metabolites of basidiomycetes often have antimicrobial properties and are screened for their use as novel medicines (Abraham, 2001 Liu, 2005). Wood-inhabiting bacteria have, so far, not been studied in this context. Yet, they may reveal a new source of antimycotica and antioxidants.

Tamas Szkely Allen J Moore and Jan Komdeur

Sociobiology is in the midst of a major paradigm shift. Early ethologists such as Konrad Lorenz, Niko Tinbergen, Karl von Frisch and their students provided a scientific basis of social behaviour by investigating group and family life, fighting, communication, display behaviours and mating. This ethological paradigm later split into studies of mechanisms (neuroethology, behavioural genetics) and function (behavioural ecology, sociobiology), as predicted by E. O. Wilson (1975). The two distinct approaches are now moving back towards each other. On the one hand, behavioural ecologists have begun to realise that functions cannot be fully understood without an appreciation of underlying mechanisms. For example, where traditionally behavioural ecologists studied how parents influence their offspring through nest attendance and feeding, modern researchers might investigate the same problem by considering the constituents of the egg in which the embryo developed, the architecture of the nest...

Biotransformation and Biodegradation of HHCs

Dichloromethane is metabolized to CO and HCHO (carcinogen). The metabolites of trihalomethanes start with loss of halide (via P4502E1), leading to CO production. Covalent bonding to macromolecules occurs via phosgene in case of chloroform and via dibromocarbonyl in the case of bromoform. Chloroform is metabolized to reactive phosgene, and carbon tetrachloride forms tri-chloromethyl, trichloromethylperoxy, and chlorine-free radicals. Several haloalkanes are first conjugated with GSH in liver and then metabolized to cysteine conjugates in kidney. The latter conjugates are converted, by 3-lyase, to episulfonium ions.

Examples of the role of life in planetary physiology on Earth

Clearly the Boreal forest could potentially act like a black daisy, what about white ones Possible examples of a white daisy are some species of marine algae. In this interesting example the 'white daisies' are not the algae themselves but an indirect by-product, namely clouds. Dimethylsulphoniopropionate (DMSP) is found at high concentrations (100-400 mmol-1) in the cells of many marine algae, including coccolithophorids and dinoflagellates. DMSP has a range of possible functions in algal cells including osmoprotection and as an antioxidant (Sim , 2001 Sunda et al., 2002). DMSP breaks down to dimethylsulphide (DMS), which is the most common form of volatile sulphur in the oceans and a major source of cloud condensation nuclei. This gives the possibility of a Daisyworld-like mechanism, often referred to as the CLAW hypothesis after the initials of the authors of the original paper suggesting this mechanism in Nature (Charlson, Lovelock, Andreae and Warren, 1987) this paper is now a...

Production and Use of Phenols by

The main method for commercial production of phenol is by peroxidation of cumene (isopropylbenzene) to cumene hydroperoxide, with subsequent cleavage to phenol and acetone. Feedstocks for this process include benzene and propylene. About 7.5 million metric tons of phenol were produced in 2004 worldwide phenol demand is expected to increase 4-6 annually over the next several years. Major uses of phenol include resins, polycarbonate and epoxy plastics, and some grades of nylon. Phenols are also produced as by-products in many industrial processes where organic chemicals are used. Butylated hydroxyl toluene (BHT) is an example of a phenolic antioxidant used as a food additive and preservative.

Individual Variability

Epidemiological evidence indicates that vitamin A is protective against lung cancer. Exposing rats to PCB, DDT, and dieldrin significantly reduced the stores of vitamin A in the liver. However, vitamin A can be toxic at high levels. On the other hand, p-carotene, which is a precursor of vitamin A, is fairly nontoxic. Vitamins E and C are both important antioxidants. Lipophilic vitamin E acts to protect the membranes from free radicals and

Biochemical and Physiological Effects

Here the discussion is not on biochemical causes of toxic effects, as discussed in Section 17.1, but on the secondary effects that are manifested biochemically. These are the changes in the operation of biochemical pathways that do not involve the toxin directly. They are the chemical response of the cell to toxin-induced damage to enzymes, reactants, or cell structures involved in reactions. As mentioned above, the distinction is sometimes arbitrary. For example, enzyme disruption by the complexation of metallic cofactors, or production of free radicals by oxidants, could both be considered secondary effects. Some

Effects on Particular Organs or Organ Systems

Mechanisms that impair the release of triglycerides to the blood. Carbon tetrachloride and ethanol are among the substances that can cause this. Necrosis is caused by carbon tetrachloride, which forms free radicals in the liver, as well as by other halogenated hydrocarbons. Cirrhosis is the formation of scar tissue in the liver. It is also caused by carbon tetrachloride, although ethanol is most commonly associated with this condition. Although there is evidence to the contrary, the effect of ethanol may be related to nutritional deficiency associated with alcoholism. Cholestasis is an inflammation of the ducts carrying bile or a decrease in bile flow by other mechanisms. There are many types of liver cancer, and many chemicals are known to cause cancer in laboratory animals. The role of chemicals in human liver cancer is less clear, except for the notable case of vinyl chloride, which is known as a potent cause of angiosarcoma.

Responses to Specific Environmental Factors

Such excess absorbed sunlight, in turn, has the potential to lead to the production of reactive oxygen species (ROS) that oxidize various macromolecules. All plants therefore dissipate excess absorbed sunlight via an alternative route, photoprotec-tive dissipation of excitation energy as harmless thermal energy (heat). In addition, plants upregulate their antioxidant pools (e.g., ascorbate, or vitamin C, and tocopherols, or vitamin E) when growing in the sun. Those plant species with a more limited maximal photosynthesis rate exhibit the strongest upregulation of the capacity for the harmless alternative dissipation of excess absorbed sunlight and other antioxidant defenses, all directed at preventing ROS accumulation.

From genotype to phenotype

An experimental approach that has been used to study genetic trade-offs is artificial selection for increased resistance to infection and subsequent measurement of correlated changes in other fitness traits. This method identifies costs of resistance, defined as changes in traits that reduce fitness in selected lines compared with unselected lines. Artificially selecting the Indian meal moth, Plodia interpunctella, for increased resistance to granulosis virus infection led to correlated increases in larval development time and pupal weight and a decrease in egg viability in selected lines (Boots and Begon, 1993). Selection in D. melanogaster for resistance to parasitoid or fungal infection led to a correlated decreases in larval competitive ability and adult fecundity, respectively, in the absence of infection (Kraaijeveld and Godfray, 1997, 2008). Costs that are measured in artificial selection lines should be interpreted with caution, however, as selection experiments can sometimes...

Plant Phenolics as Pigments and Flavors

Condensed tannins (also referred to as proanthocyanidins) are flavonoid units linked by carbon-carbon bonds that are not susceptible to cleavage by hydrolysis. These compounds are responsible for the intense pink, red, purple, or blue colors of many flowers, fruits, and leaves. Flavonoids, mainly anthocyanins, are responsible for the bright autumn colors in many plant species. Other flavo-noid pigments having antioxidant properties (quercetins) also increases dramatically in plants, especially in epidermal

Valuable and Bioactive Compounds

Due to their phototrophic life, microalgae experience high oxygen and radical stresses. Their protective mechanisms, based on highly effective oxygen radical scavengers, prevent the accumulation of free radicals and reactive oxygen species (e.g., superoxide anion, hydroxyl radical, or singlet oxygen), thus avoiding cell damage. For example, the antioxidative potential of Spirulina can increase 2.3 fold during O2 stress. Of parti cular note is the high content in lipophilic scavengers, such as carotenoids, especially ft carotene and a toco pherol minerals and trace elements with an antioxidative effect, such as zinc and selenium and enzymatic scaven gers, such as catalase, superoxide dismutase, and peroxidase, and vitamins C and E.

Water And Wastewater Disinfection Treatment

Ionizing radiation using x-ray and gamma-ray beams with even higher energy levels than that of UV irradiation, can also be used in water, wastewater, and sludge disinfection. These ionizing mechanisms displace electrons during beam bombardment (i.e., at which point they are said to ionize), and in the presence of oxygen these displaced electrons elec-trochemically form a type of free radical (called hydroxyl radicals) that is highly toxic to microbial cells. Free radicals are highly reactive, having essentially no activation energy for their reaction. Given the acutely reactive nature of these radicals, they readily attack and destroy hydrogen bonds, double bonds, and ring structures essential to the metabolic utility of various cellular molecules. Yet another operative mechanism, and perhaps the key factor behind disinfection with ionizing irradiation, is that of a polymerizing impact (e.g., DNA thymine dimerization) whereby the biochemical effectiveness of complex molecules is...

PAH Toxicity

PAHs can degrade quickly via exposure to sunlight -in contrast, PAH half-lives in marine sediments range from months to years. In general, PAHs exposed to solar radiation can result in greater toxicity (phototoxi-city), as free radicals which react with oxygen to form reactive oxygen species such as singlet molecular oxygen are generated. These reactive species can then target and damage important macromolecules such as nucleic acids (i.e., DNA, RNA) and proteins. The reactive singlet molecular oxygen may potentially destroy gill or skin membranes of fish, impairing respiration. Photoenhanced toxicity has been reported in bivalve embryos, marine invertebrates, and fish.

Phenolic Resins

Phenolic compounds, those that include an aromatic ring plus at least one hydroxyl group (OH), are a dazzlingly diverse group of plant products. They are equally diverse in function, which includes structural support (lignin), pigmentation of flowers and other organs, protection from antioxidants and ultraviolet light, signaling between plants and animals or microbes, and plant


Various unsaturated fatty acids in microalgal biomass are important as dietary supplements to prevent various diseases (e.g., high plasma cholesterol, hypertension, etc.) and to boost the immune system. Microalgal biomass also contains all the important vitamins, especially the B1, B2, and C vitamins and nicotinic acid. The variety of carotenoids is greater than in higher plants - ft carotene, lutein, violaxanthin, zeaxanthin, neoxanthin, etc. Among them, the oxygenated xanthophylls, astaxanthin and canthaxanthin, are massively used both as colorants and antioxidants in aquacultures (fish and Crustacea).

Box 123

Other transition metals like Cu may also be used in this process. Some white rots produce these low-molecular-weight oxidants through lipid peroxidation. These potent free radicals are capable of significant lignin degradation in the absence of the larger lignin-degrading enzymes.


Oxidative damage occurs as a result of interaction of free radicals or singlet oxygen (molecular oxygen in an excited state) with DNA. The most common oxyradicals include hydroxide radicals (OH ) and the superoxide anion O . Oxyradicals and singlet oxygen are potential mutagenic chemicals known as reactive oxygen species (ROSs). These ROSs are produced to some extent by endogenous metabolic processes, for example, during mitochondrial respiration, metabolism of natural and man-made hydrocarbons, and metabolism of fats. However, some chemicals may stimulate cells to overproduce ROSs metabolically. Besides metabolic processes, some hydrocarbons and heavy metals may convert molecular oxygen to superoxide.

Biological Defenses

The majority of prokaryotic and eukaryotic species synthesize UV-absorbing compounds that can serve as natural sunscreens (Table 1). Many of these compounds are common across taxonomic groups and have multiple functions they not only provide protection from UV, but can act as antioxidants, signal transducers, osmoregulators, structural components, etc. UV-absorbing compounds can be colorless substances (e.g. mycosporine-like amino acids) or pigments (e.g., melanin). Many are secondary metabolites produced via pathways involved with the synthesis of aromatic amino acids. Table 1 Some of the common UV-absorbing compounds that serve as sunscreens and examples of representative taxa. Many of these compounds absorb most strongly in the UVA, but attenuate UVB wavelengths as well. Within each of these groups, some compounds also can act as antioxidants. Presence in a particular taxonomic group does not necessarily indicate the ability to synthesize the UV-absorbing compounds animals often...

Air Pollutants

Ozone (O3) is formed in various ways, including direct photolysis of oxygen (O2) by ultraviolet light from sunlight or from equipment, or by spark discharges from motors, static discharges, electrostatic air purifiers, and by lightning. UV from sunlight produces the stratospheric ozone layer that protects the surface from the same ultraviolet radiation. However, in the troposphere (the lower atmosphere) an environmentally more significant mechanism is the complex sequence of reactions that form photochemical smog. In these reactions, NO2 and oxygen react to form ozone and NO. Normally, the equilibrium would favor a low ozone concentration. However, atmospheric hydrocarbons, such as from incomplete products of combustion, react to form free radicals. The organic radicals scavenge the NO, shifting the equilibrium to the right. The entire sequence is a chain reaction regenerating the NO2, resulting in many ozone molecules produced for each NO2 initially available. Another important...

Ionizing Radiation

An important physical cause of toxic effects is a variety of forms of radiation. Ionizing radiation possesses enough energy to strip an electron from an atom. This can result in the formation of damaging free radicals or directly damage bonds in biochemical substances. The most sensitive system in living things is the DNA, since damage to a single molecule can transform a cell to malignancy. It is not necessary for a radioactive emission to damage a DNA molecule directly. The most abundant molecule in living things is water. Water can form free radicals when irradiated, and these in turn can produce toxic effects, including genotoxicity.