Evaluation of antioxidant capacity and total phenolic content of different fractions of selected microalgae
TL;DR: In this article, the antioxidant capacity and total phenolic content of 23 microalgae were evaluated, using Trolox equivalent antioxidant capacity assay and the Folin-Ciocalteu method, respectively.
About: This article is published in Food Chemistry.The article was published on 2007-01-01. It has received 631 citations till now. The article focuses on the topics: Trolox equivalent antioxidant capacity.
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TL;DR: Animal studies have revealed the promising in vivo therapeutic effect of antioxidants on liver diseases, and various factors that cause oxidative stress in liver and effects of antioxidants in the prevention and treatment of liver diseases were summarized, questioned, and discussed.
Abstract: A complex antioxidant system has been developed in mammals to relieve oxidative stress. However, excessive reactive species derived from oxygen and nitrogen may still lead to oxidative damage to tissue and organs. Oxidative stress has been considered as a conjoint pathological mechanism, and it contributes to initiation and progression of liver injury. A lot of risk factors, including alcohol, drugs, environmental pollutants and irradiation, may induce oxidative stress in liver, which in turn results in severe liver diseases, such as alcoholic liver disease and non-alcoholic steatohepatitis. Application of antioxidants signifies a rational curative strategy to prevent and cure liver diseases involving oxidative stress. Although conclusions drawn from clinical studies remain uncertain, animal studies have revealed the promising in vivo therapeutic effect of antioxidants on liver diseases. Natural antioxidants contained in edible or medicinal plants often possess strong antioxidant and free radical scavenging abilities as well as anti-inflammatory action, which are also supposed to be the basis of other bioactivities and health benefits. In this review, PubMed was extensively searched for literature research. The keywords for searching oxidative stress were free radicals, reactive oxygen, nitrogen species, anti-oxidative therapy, Chinese medicines, natural products, antioxidants and liver diseases. The literature, including ours, with studies on oxidative stress and anti-oxidative therapy in liver diseases were the focus. Various factors that cause oxidative stress in liver and effects of antioxidants in the prevention and treatment of liver diseases were summarized, questioned, and discussed.
1,112 citations
TL;DR: Seven fruits, Chinese date, pomegranate, guava, sweetsop, persimmon, Chinese wampee and plum, possessed the highest antioxidant capacities and total phenolic contents among tested fruits, and could be important dietary sources of natural antioxidants for prevention of diseases caused by oxidative stress.
593 citations
Additional excerpts
...In recent years, there is considerable interest in determining total phenolic contents and antioxidant capacities of vegetables, fruits, spices, medicinal plants and microalgae (Cai, Luo, Sun, & Corke, 2004; Gan et al., 2010; Ghasemzadeh, Jaafar, & Rahmat, 2010; Li et al., 2007; Li, Wong, Cheng, & Chen, 2008; Stangeland, Remberg, & Lye, 2009; Wong, Li, Cheng, & Chen, 2006)....
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TL;DR: This review summarizes current knowledge of natural polyphenols, including resource, bioactivities, bioavailability and potential toxicity.
Abstract: The oxidative stress imposed by reactive oxygen species (ROS) plays an important role in many chronic and degenerative diseases. As an important category of phytochemicals, phenolic compounds universally exist in plants, and have been considered to have high antioxidant ability and free radical scavenging capacity, with the mechanism of inhibiting the enzymes responsible for ROS production and reducing highly oxidized ROS. Therefore, phenolic compounds have attracted increasing attention as potential agents for preventing and treating many oxidative stress-related diseases, such as cardiovascular diseases, cancer, ageing, diabetes mellitus and neurodegenerative diseases. This review summarizes current knowledge of natural polyphenols, including resource, bioactivities, bioavailability and potential toxicity.
568 citations
Cites background from "Evaluation of antioxidant capacity ..."
...Natural polyphenols have been found in many plants and foods, such as fruits, vegetables, tea, cereals, medical plants, microalgae, and edible and wild flowers [6–15]....
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TL;DR: In this article, the antioxidant capacities of 45 medicinal plants were evaluated using ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, respectively, and the total phenolic contents of these plants were measured by the Folin-Ciocalteu method.
Abstract: In order to find out new sources of safe and inexpensive antioxidants, the antioxidant capacities of 45 selected medicinal plants were evaluated using ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, respectively, and the total phenolic contents of these plants were measured by the Folin–Ciocalteu method. Most of these plants were analyzed for the first time for their antioxidant activities. It was found that the plants Sargentodoxa cuneata Rehd. Et Wils, Fraxinus rhynchophylla Hance, Paeonia lactiflora Pall, Paeonia suffruticosa Andr and Scutellaria baicalensis Ceorgi possessed the highest antioxidant capacities and thus could be potential rich sources of natural antioxidants. A strong correlation between TEAC values and those obtained from FRAP assay implied that antioxidants in these plants were capable of scavenging free radicals and reducing oxidants. A high correlation between antioxidant capacities and their total phenolic contents indicated that phenolic compounds were a major contributor of antioxidant activity of these plants.
487 citations
TL;DR: Chloroform–methanol 1:1 was shown to be the best solvent mixture for extraction of total lipids from microalgae and determination of non-polar lipid content should be performed by separation of the total lipid extract on an SPE column.
Abstract: An optimized procedure for extraction of total and non-polar lipids from microalgae is proposed. The effects of solvent, pretreatment (lyophilization, inactivation of lipases, and addition of antioxidants) and cell-disruption (liquid nitrogen, sonication, and bead beating) on total lipid content, lipid class, and fatty acid composition were examined. Chloroform–methanol 1:1 was shown to be the best solvent mixture for extraction of total lipids from microalgae. When performing this extraction, lyophilized algae can be used, no pretreatment with isopropanol to inactivate the lipases is needed and addition of antioxidants is not necessary. Furthermore, cell-disruption is not essential, although in that case two extractions must be performed in series to ensure that, irrespective of the microalgal species, all lipids are extracted. Determination of non-polar lipid content should be performed by separation of the total lipid extract on an SPE column. Extraction using petroleum ether is only appropriate when a bead beater is used for pretreatment.
421 citations
Cites background from "Evaluation of antioxidant capacity ..."
..., known to be present in microalgae [14], protect the lipid extracts....
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...Algae are however, known to contain a large amount of natural antioxidants [14], leading to a large antioxidant capacity of microalgal extracts (our own preliminary results)....
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References
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Journal Article•
TL;DR: In this paper, the use of Folin-Ciocalteu reagent rather than the FolinDenis reagent, gallic acid as a reference standard, and a more reproducible time-temperature color development period was investigated.
Abstract: Several details of the assay of total phenolic substances have been investigated and an improved procedure developed. The improvements include the use of Folin-Ciocalteu reagent rather than the Folin-Denis reagent, gallic acid as a reference standard, and a more reproducible time-temperature color development period. The values obtained are less subject to variation and interference from several nonphenols, yet are directly comparable to the "tannin" values obtained by the previously standard method.
18,629 citations
TL;DR: A method for the screening of antioxidant activity is reported as a decolorization assay applicable to both lipophilic and hydrophilic antioxidants, including flavonoids, hydroxycinnamates, carotenoids, and plasma antioxidants.
18,580 citations
TL;DR: Evidence that the appropriate and inappropriate production of oxidants, together with the ability of organisms to respond to oxidative stress, is intricately connected to ageing and life span is reviewed.
Abstract: Living in an oxygenated environment has required the evolution of effective cellular strategies to detect and detoxify metabolites of molecular oxygen known as reactive oxygen species. Here we review evidence that the appropriate and inappropriate production of oxidants, together with the ability of organisms to respond to oxidative stress, is intricately connected to ageing and life span.
8,665 citations
TL;DR: Traditional Chinese medicinal plants associated with anticancer might be potential sources of potent natural antioxidants and beneficial chemopreventive agents, and contain significantly higher levels of phenolics than common vegetables and fruits.
2,562 citations
TL;DR: The aim of this review is to summarize and analyze the vast and sometimes conflicting literature on tannins and to provide as accurately as possible the needed information for assessment of the overall effects of tannin effects on human health.
Abstract: Tannins (commonly referred to as tannic acid) are water-soluble polyphenols that are present in many plant foods. They have been reported to be responsible for decreases in feed intake, growth rate, feed efficiency, net metabolizable energy, and protein digestibility in experimental animals. Therefore, foods rich in tannins are considered to be of low nutritional value. However, recent findings indicate that the major effect of tannins was not due to their inhibition on food consumption or digestion but rather the decreased efficiency in converting the absorbed nutrients to new body substances. Incidences of certain cancers, such as esophageal cancer, have been reported to be related to consumption of tannins-rich foods such as betel nuts and herbal teas, suggesting that tannins might be carcinogenic. However, other reports indicated that the carcinogenic activity of tannins might be related to components associated with tannins rather than tannins themselves. Interestingly, many reports indicated negative association between tea consumption and incidences of cancers. Tea polyphenols and many tannin components were suggested to be anticarcinogenic. Many tannin molecules have also been shown to reduce the mutagenic activity of a number of mutagens. Many carcinogens and/or mutagens produce oxygen-free radicals for interaction with cellular macromolecules. The anticarcinogenic and antimutagenic potentials of tannins may be related to their antioxidative property, which is important in protecting cellular oxidative damage, including lipid peroxidation. The generation of superoxide radicals was reported to be inhibited by tannins and related compounds. The antimicrobial activities of tannins are well documented. The growth of many fungi, yeasts, bacteria, and viruses was inhibited by tannins. We have also found that tannic acid and propyl gallate, but not gallic acid, were inhibitory to foodborne bacteria, aquatic bacteria, and off-flavor-producing microorganisms. Their antimicrobial properties seemed to be associated with the hydrolysis of ester linkage between gallic acid and polyols hydrolyzed after ripening of many edible fruits. Tannins in these fruits thus serve as a natural defense mechanism against microbial infections. The antimicrobial property of tannic acid can also be used in food processing to increase the shelf-life of certain foods, such as catfish fillets. Tannins have also been reported to exert other physiological effects, such as to accelerate blood clotting, reduce blood pressure, decrease the serum lipid level, produce liver necrosis, and modulate immunoresponses. The dosage and kind of tannins are critical to these effects. The aim of this review is to summarize and analyze the vast and sometimes conflicting literature on tannins and to provide as accurately as possible the needed information for assessment of the overall effects of tannins on human health.
1,687 citations