Antioxidant Potential Of Carotenoids Research Articles

Industrially Important Fungal Carotenoids: Advancements in Biotechnological Production and Extraction.

Carotenoids are lipid-soluble compounds that are present in nature, including plants and microorganisms such as fungi, certain bacteria, and algae. In fungi, they are widely present in almost all taxonomic classifications. Fungal carotenoids have gained special attention due to their biochemistry and the genetics of their synthetic pathway. The antioxidant potential of carotenoids may help fungi survive longer in their natural environment. Carotenoids may be produced in greater quantities using biotechnological methods than by chemical synthesis or plant extraction. The initial focus of this review is on industrially important carotenoids in the most advanced fungal and yeast strains, with a brief description of their taxonomic classification. Biotechnology has long been regarded as the most suitable alternative way of producing natural pigment from microbes due to their immense capacity to accumulate these pigments. So, this review mainly presents the recent progress in the genetic modification of native and non-native producers to modify the carotenoid biosynthetic pathway for enhanced carotenoid production, as well as factors affecting carotenoid biosynthesis in fungal strains and yeast, and proposes various extraction methods to obtain high yields of carotenoids in an attempt to find suitable greener extraction methods. Finally, a brief description of the challenges regarding the commercialization of these fungal carotenoids and the solution is also given.

A multifocal approach towards understanding the complexities of carotenoid biosynthesis and accumulation in rice grains.

Carotenoids are mostly C40 terpenoids that participate in several important functions in plants including photosynthesis, responses to various forms of stress, signal transduction and photoprotection. While the antioxidant potential of carotenoids is of particular importance for human health, equally important is the role of β-carotene as the precursor for vitamin A in the human diet. Rice, which contributes upto 40% of dietary energy for mankind, contains very low level of β-carotene, thereby making it an important crop for enhancing β-carotene accumulation in its grains and consequently targeting vitamin A deficiency. Biosynthesis of carotenoids in the endosperm of white rice is blocked at the first enzymatic step wherein geranylgeranyl diphosphate is converted to phytoene by the action of phytoene synthase (PSY). Strategies aimed at enhancing β-carotene levels in the endosperm of white rice identified Narcissus pseudonarcissus (npPSY) and bacterial CRT1 as the regulators of the carotenoid biosynthetic pathway in rice. Besides transcriptional regulation of PSY, posttranscriptional regulation of PSY expression by OR gene, molecular synergism between ε-LCY and β-LCY and epigenetic control of CRITSO through SET DOMAIN containing protein appear to be the other regulatory nodes which regulate carotenoid biosynthesis and accumulation in rice grains. In this review, we elucidate a comprehensive and deeper understanding of the regulatory mechanisms of carotenoid metabolism in crops that will enable us to identify an effective tool to alleviate carotenoid content in rice grains.

Food matrix: Natural barrier or vehicle for effective delivery of carotenoids from processed foods?

Carotenoids are lipophilic compounds naturally occurring in plant species where they exert their main biological role as photosynthetic pigments. Due to their chemical structure, carotenoids have the ability to act as antioxidants primarily by scavenging reactive oxygen species. The antioxidant potential of carotenoids is of significant importance to human health and a carotenoidrich diet is recommended for the prevention of a number of chronic and age-related diseases. The bioaccessibily and bioavailabilty of carotenoids is not proportional to their relative abundance in the original food matrix. The structural integrity of the plant material in which they are embedded and their chemical interactions with other food components seem to be critical factors for their release from the food source and their subsequent uptake by cells at the intestinal epithelium. In addition to food microstructure, food processing is also important for carotenoid bioavailabilty. Heat treatment, acidification and exposure to light can induce isomerisation and oxidation of the phytochemical compounds. It is evident that the absorption of carotenoids in a biologically active form is a complex, multi-step process depending on many variables. In this context the aim of this review is to present and critically discuss evidence relating to the association between food processing and carotenoid bioavailability. Emphasis is given on the food matrix composition and the chemical properties of the individual phytochemicals for formulating conclusions on carotenoid availability from processed meals.

When Parasites Are Good for Health: Cestode Parasitism Increases Resistance to Arsenic in Brine Shrimps.

Parasites and pollutants can both affect any living organism, and their interactions can be very important. To date, repeated studies have found that parasites and heavy metals or metalloids both have important negative effects on the health of animals, often in a synergistic manner. Here, we show for the first time that parasites can increase host resistance to metalloid arsenic, focusing on a clonal population of brine shrimp from the contaminated Odiel and Tinto estuary in SW Spain. We studied the effect of cestodes on the response of Artemia to arsenic (acute toxicity tests, 24h LC50) and found that infection consistently reduced mortality across a range of arsenic concentrations. An increase from 25°C to 29°C, simulating the change in mean temperature expected under climate change, increased arsenic toxicity, but the benefits of infection persisted. Infected individuals showed higher levels of catalase and glutathione reductase activity, antioxidant enzymes with a very important role in the protection against oxidative stress. Levels of TBARS were unaffected by parasites, suggesting that infection is not associated with oxidative damage. Moreover, infected Artemia had a higher number of carotenoid-rich lipid droplets which may also protect the host through the “survival of the fattest” principle and the antioxidant potential of carotenoids. This study illustrates the need to consider the multi-stress context (contaminants and temperature increase) in which host-parasite interactions occur.

Potential Role of Carotenoids as Antioxidants in Human Health and Disease

Carotenoids constitute a ubiquitous group of isoprenoid pigments. They are very efficient physical quenchers of singlet oxygen and scavengers of other reactive oxygen species. Carotenoids can also act as chemical quenchers undergoing irreversible oxygenation. The molecular mechanisms underlying these reactions are still not fully understood, especially in the context of the anti- and pro-oxidant activity of carotenoids, which, although not synthesized by humans and animals, are also present in their blood and tissues, contributing to a number of biochemical processes. The antioxidant potential of carotenoids is of particular significance to human health, due to the fact that losing antioxidant-reactive oxygen species balance results in “oxidative stress”, a critical factor of the pathogenic processes of various chronic disorders. Data coming from epidemiological studies and clinical trials strongly support the observation that adequate carotenoid supplementation may significantly reduce the risk of several disorders mediated by reactive oxygen species. Here, we would like to highlight the beneficial (protective) effects of dietary carotenoid intake in exemplary widespread modern civilization diseases, i.e., cancer, cardiovascular or photosensitivity disorders, in the context of carotenoids’ unique antioxidative properties.

Biologic Activity of Carotenoids Related to Distinct Membrane Physicochemical Interactions

Carotenoids are naturally occurring organic pigments that are believed to have therapeutic benefit in treating cardiovascular disease (CVD) because of their antioxidant properties. However, prospective randomized trials have failed to demonstrate a consistent benefit for the carotenoid beta-carotene in patients at risk for CVD. The basis for this apparent paradox is not well understood but may be attributed to the distinct antioxidant properties of various carotenoids resulting from their structure-dependent physicochemical interactions with biologic membranes. To test this hypothesis, we measured the effects of astaxanthin, zeaxanthin, lutein, beta-carotene, and lycopene on lipid peroxidation using model membranes enriched with polyunsaturated fatty acids. The correlative effects of these compounds on membrane structure were determined using small-angle x-ray diffraction approaches. The nonpolar carotenoids, lycopene and beta-carotene, disordered the membrane bilayer and stimulated membrane lipid peroxidation (>85% increase in lipid hydroperoxide levels), whereas astaxanthin (a polar carotenoid) preserved membrane structure and exhibited significant antioxidant activity (>40% decrease in lipid hydroperoxide levels). These results suggest that the antioxidant potential of carotenoids is dependent on their distinct membrane lipid interactions. This relation of structure and function may explain the differences in biologic activity reported for various carotenoids, with important therapeutic implications.

Pigments in food: a challenge to life sciences

The fourth International Congress on Pigments in Food (PF IV) subtitled “A challenge to life sciences” was held in Stuttgart/Germany, from 9th to 12th October, 2006 and was organised by the Department of Plant FoodstuV Technology at Hohenheim University. The aim of this conference was to bring together pigment experts from all over the world from various scientiWc disciplines such as chemistry, food chemistry, food technology, biotechnology, nutritional and agricultural sciences as well as further Welds of applied science with a major focus on carotenoids, chlorophylls, anthocyanins and betalains. The conference was attended by 132 participants from 32 countries, representing both academia and industry. After welcome addresses by Professor H.-P. Liebig (Rector of Hohenheim University), Professor J. Empis (EuCheMS) and Professor R. Carle (Conference Chair) and a solemn musical introduction, Professor P. Winterhalter (Technical University of Braunschweig, Germany) opened the Wrst session with his keynote lecture Application of countercurrent chromatography to the analysis of natural pigments providing an overview about uses and advantages of this technique for pigment separation and puriWcation, illustrated with various applications. On the following days three further plenary lectures on diVerent topics were given. Professor S.J. Schwartz (Ohio State University, USA) delivered a presentation on Carotenoids and their bioavailability in which the multiple impacts of dietary factors on bioabsorption were highlighted. Dr. F.C. Stintzing (Hohenheim University, Germany) spoke about Betalains—a bunch of colours for food scientists and pointed out the progress in the investigation of this still underestimated pigment class, particularly in structure elucidation, structural alterations and colour stability during processing and nutritional evaluation. Professor G. Britton (University of Liverpool, UK) presented the fourth keynote lecture “How pigments are made? Can we follow Nature’s examples?” which was not only an overview about biosynthetic pathways of various pigment classes, but also prospect for future pigment production by biotechnological means. These four comprehensive plenaries were completed by 24 oral and 66 poster presentations. Moreover, six posters had been selected for short oral presentations and discussed in a special section. A variety of thematic areas were divided into four main sections. The Wrst topic, Analysis and Chemistry of Pigments addressed analytical methods for the isolation and determination of pigments in food. Structural alterations and the variability of pigments as well as the detection of new pigments in Mexican plants and Eugenia myrtifolia were also considered. Among others, the pigment and colour variability in black carrots and tandem mass spectrometry as a powerful tool to assign anthocyanins were covered. Furthermore, alternative sources for natural food colourants were presented, e.g. new yellow soluble pigments from apple following phloridzin oxidation or betalains from Hylocereus sp. fruits. The next section entitled Biological and Nutritional Properties of Pigments included reports on the cytoprotective eVects of selected carotenoids and betalains from citrus and cactus pear, antimicrobial properties of cranberry and the antioxidant potential of carotenoids, E. Sadilova (&) Stuttgart, Germany e-mail: eva.sadilova@email.cz

Serum Carotenoid and Retinol Levels during Childhood Infections

Background: In recent years, new physiological functions of vitamin A have been identified, including its role in immune defense. The antioxidant potential of carotenoids is thought to account for their health benefits. The aim of this study was to investigate the concentration changes in the provitamin-A (α- and-β-carotene, β-cryptoxanthin) and of the non-provitamin-A carotenoids (lutein, zeaxanthin and lycopene) in children with acute infections. Methods: Serum retinol and carotenoid concentrations were measured by HPLC in 45 children suffering from acute infections and in 29 healthy controls. In addition 15 healthy children collected food samples over 2 days. C-reactive protein (CRP) levels were measured by turbidimetry. Results: Serum levels of β-carotene, α-carotene, β-cryptoxanthin and retinol and non-provitamin-A carotenoid lutein and zeaxanthin concentrations were significantly lower in children with infections compared to healthy controls. There were significant negative correlations between CRP levels and serum β-carotene and retinol concentrations. The average intake of retinol equivalents was 1.1 ± 0.6 mg/day. Conclusion: Serum retinol and provitamin-A as well as non-provitamin-A carotenoid concentrations were lower in children with acute phase infections compared to healthy controls. The inverse correlations between CRP and β-carotene or retinol indicate either decreased synthesis or increased utilization of these antioxidants.