Inhibition of free radical-mediated oxidation of cellular biomolecules by carboxylated chitooligosaccharides

Chitooligosaccharide and Its Derivatives: Potential Candidates as Food Additives and Bioactive Components

Chitooligosaccharide (CHOS), a depolymerized chitosan, can be prepared via physical, chemical, and enzymatic hydrolysis, or a combination of these techniques. The superior properties of CHOS have attracted attention as alternative additives or bioactive compounds for various food and biomedical applications. To increase the bioactivities of a CHOS, its derivatives have been prepared via different methods and were characterized using various analytical methods including FTIR and NMR spectroscopy. CHOS derivatives such as carboxylated CHOS, quaternized CHOS, and others showed their potential as potent anti-inflammatory, anti-obesity, neuroprotective, and anti-cancer agents, which could further be used for human health benefits. Moreover, enhanced antibacterial and antioxidant bioactivities, especially for a CHOS-polyphenol conjugate, could play a profound role in shelf-life extension and the safety assurance of perishable foods via the inhibition of spoilage microorganisms and pathogens and lipid oxidation. Also, the effectiveness of CHOS derivatives for shelf-life extension can be augmented when used in combination with other preservative technologies. Therefore, this review provides an overview of the production of a CHOS and its derivatives, as well as their potential applications in food as either additives or nutraceuticals. Furthermore, it revisits recent advancements in translational research and in vivo studies on CHOS and its derivatives in the medical-related field.

Protective Effect of Chitosan Oligosaccharide against Hydrogen Peroxide-Mediated Oxidative Damage and Cell Apoptosis via Activating Nrf2/ARE Signaling Pathway

Chitosan oligosaccharide (COS), hydrolyzed and deacetylated from chitosan, has been reported to possess varieties of biological activities. Alzheimer's disease (AD) is a multifactorial progressive neurodegenerative disorder characterized by cognitive decline and memory loss, where oxidative stress was reported to be an overwhelming cause of the occurrence of AD. We have previously reported that COS could significantly decrease cell death, ROS generation, and lipid peroxidation, though the potential mechanism was yet to be determined. This study was designed to investigate the neuroprotective effect of COS against hydrogen peroxide (H2O2)-induced oxidative stress and apoptosis in neuronal SH-SY5Y cells. Our results indicated that COS could dose-dependently scavenge H2O2 in the cell-free systems. Accordingly, COS markedly decreased H2O2-induced cell apoptosis and intracellular ROS generation, while increased antioxidant capacity in SH-SY5Y cells. Further, COS significantly reduced the expression of Bax and upregulated Bcl-2. The mRNA and protein expression levels of nuclear Nrf2, heme oxygenase 1 (HO-1), and NAD(P)H: quinone oxidoreductase 1 (NQO1) were significantly increased upon COS treatment. Moreover, Nrf2-siRNA evidently reversed the promotive effect of COS on expression levels of HO-1 and NQO1, and ARE-driven transcriptional activity as determined by double-luciferase reporter gene assay. Besides, COS reversed H2O2-mediated increased phosphorylation of ERK1/2 and p38 MAPK. In conclusion, our findings indicate that COS could protect SH-SY5Y cells from oxidative damage and apoptosis via regulating Nrf2/ARE signaling pathway, which may provide new applications for the prevention and treatment of AD.

The impact of chitooligosaccharides and their derivatives on the in vitro and in vivo antitumor activity: A comprehensive review

Chitooligosaccharides (COS) are the degraded products of chitin or chitosan. COS is water-soluble, non-cytotoxic to organisms, readily absorbed through the intestine, and eliminated primarily through the kidneys. COS possess a wide range of biological activities, including immunomodulation, cholesterol-lowering, and antitumor activity. Although work on COS goes back at least forty years, several aspects remain unclear. This review narrates the recent developments in COS antitumor activities, while paying considerable attention to the impacts of physicochemical properties (such as molecular weight and degrees of deacetylation) and chemical modifications both in vitro and in vivo. COS derivatives not only improve some physicochemical properties, but also expand the range of applications in drug and gene delivery. COS (itself or as a drug carrier) can inhibit tumor cell proliferation and metastasis, which might be attributed to its ability to stimulate the immune response along with its anti-angiogenic activity. Further, an attempt has been made to report limitations and future research. The potential health benefits of COS and its derivatives against cancer may offer a new insight on their applications in food and medical fields.

Protective effects of Saraca indica L. leaves extract (family Fabaceae) against gamma irradiation induced injury in the kidney of female albino rats

This work was designed to estimate the protective effect of Saraca indica L. leaves ethanolic exract against γ-irradiation induced renal damage in rats. Phytochemical examinations of S. indica L. leaves extract resulted in the separation of three flavanone glycosides: Astilibin (1), Neoastilbin (2), and Eriodictyol-7-O-α-l-rhamnopyranoside (3); two flavonols: Quercetin (4) and Quercetin-3-O-α-l-arabinopyranosyl-(1'''-6'')-O-β-D-galactopyranoside (5) in addition of Gallic acid (6) and methyl gallate (7). Their structures elucidated by chemical evidences and spectroscopic analysis (1 and 2D-NMR, -ESI-MS, UV). Female rats were used and classified into: control, Ext (200 mg/kg body wt/day orally for 7 days), IRR (8Gy), Ext + IRR, and Sily+IRR groups (received silymarin 50 mg/kg b.wt orally as reference drug). Results showed that S. indica L. leaves extract ameliorated the kidney function tests, hs-CRP, IL-1β, ACE, TNF-α, GSH, and MDA as well as, decreased the histopathological changes of kidney. In conclusion, S. indica L. leaves extract had a renoprotective activity against irradiation induced renal injury due to its flavononid contents.

Ameliorative effect of kefir against γ-irradiation induced liver injury in male rats: impact on oxidative stress and inflammation

Ionizing radiation is a double-edged sword because of its benefits and risks to human health. Therefore, protecting human organs from harmful effects of radiation is an important concern of researchers. Kefir, as a good source of probiotics, received growing interest in protective medicine owing to its antioxidant, anti-inflammatory, and immunomodulatory properties. Thus, this study was planned to investigate the protective role of kefir against γ-radiation-induced hepatotoxicity. Thirty-two male rats were distributed in four groups: (I) control, (II) received Kefir orally (5 ml/kg body weight) for 28 days, (III) exposed to whole body γ-irradiation (6.5 Gy) to induce hepatotoxicity, and (IV) was pretreated with kefir for 21 days then exposed to γ-irradiation followed by 7 days of kefir treatment. At the end of the experiment, complete blood picture (CBC), liver function, and lipid profile were estimated. Furthermore, levels of lipid peroxidation, nitric oxide content, and endogenous antioxidants, in addition to concentrations of copper, iron, and calcium were measured in liver tissue. Furthermore, monocyte chemoattractant protein-1 (MCP-1) and relative gene expression of nuclear factor kappa (NF-κB) were assessed. The results revealed that oral administration of kefir significantly reduced the radiation-induced hepatic histological alterations, hepatic function impairment, and dyslipidemia. Moreover, kefir notably ameliorated the state of oxidative stress and appeared to inhibit the induced inflammation. This study provides a possible counteracting role of kefir against hepatotoxicity induced γ-radiation. This can focus the benefit of kefir application as a prophylactic treatment to limit hepatic inflammation during radiotherapy.

Chemoenzymatic Production and Engineering of Chitooligosaccharides and N-acetyl Glucosamine for Refining Biological Activities

Chitooligosaccharides (COS) and N-acetyl glucosamine (GlcNAc) are currently of enormous relevance to pharmaceutical, nutraceutical, cosmetics, food, and agriculture industries due to their wide range of biological activities, which include antimicrobial, antitumor, antioxidant, anticoagulant, wound healing, immunoregulatory, and hypocholesterolemic effects. A range of methods have been developed for the synthesis of COS with a specific degree of polymerization along with high production titres. In this respect, chemical, enzymatic, and microbial means, along with modern genetic manipulation techniques, have been extensively explored; however no method has been able to competently produce defined COS and GlcNAc in a mono-system approach. Henceforth, the chitin research has turned toward increased exploration of chemoenzymatic processes for COS and GlcNAc generation. Recent developments in the area of green chemicals, mainly ionic liquids, proved vital for the specified COS and GlcNAc synthesis with better yield and purity. Moreover, engineering of COS and GlcNAc to generate novel derivatives viz. carboxylated, sulfated, phenolic acid conjugated, amino derived COS, etc., further improved their biological activities. Consequently, chemoenzymatic synthesis and engineering of COS and GlcNAc emerged as a useful approach to lead the biologically-active compound-based biomedical research to an advanced prospect in the forthcoming era.

Chitin/Chitosan and Its Derivatives: Fundamental Problems and Practical Approaches

In this review, we present the data on the natural occurrence of chitin and its partially or fully deacetylated derivative chitosan, as well as their properties, methods of modification, and potential applications of derivatives with bactericidal, fungicidal, and antioxidant activities. The structure and physicochemical characteristics of the polymers, their functions, and features of chitin microbial synthesis and degradation, including the processes occurring in nature, are described. New data on the hydrolytic microorganisms capable of chitin degradation under extreme conditions are presented. Special attention is focused on the effect of physicochemical characteristics of chitosan, including molecular weight, degree of deacetylation, polydispersity index, and number of amino group derivatives (quaternized, succinyl, etc.) on the antimicrobial and antioxidant properties of modified polymers that can be of particular interest for biotechnology, medicine, and agriculture. Analysis of the available literature data confirms the importance of fundamental research to broaden our knowledge on the occurrence of chitin and chitosan in nature, their role in global biosphere cycles, and prospects of applied research aimed at using chitin, chitosan, and their derivatives in various aspects of human activity.

Antiproliferative Effect of Aminoethyl-Chitooligosaccharide on Human Lung A549 Cancer Cells

The aminoethyl–chitooligosaccharide (AE-COS) was reported to inhibit human gastric cancer cell proliferation and human fibrosarcoma cell invasion. In this study, the role of AE-COS in down-regulation of proliferation of human lung A549 cancer cells was evaluated. It was found that AE-COS was able to reduce A549 cell proliferation to (32 ± 1.3)% at a concentration of 500 µg/mL. Moreover, AE-COS treatment caused suppression on COX-2 expression in a dose-dependent manner. Notably, the role of AE-COS in induction of cell apoptosis was observed via decreasing Bcl-2 expression and increasing caspase-3 and -9 activation. Accordingly, the antiproliferative effect of AE-COS was indicated due to suppression of cell proliferation and induction of cell apoptosis, suggesting AE-COS as a promising chemotherapy agent for treatment of lung cancer.

Elevated Inactivation Efficacy of a Pulsed UVC Light-Emitting Diode System for Foodborne Pathogens on Selective Media and Food Surfaces

UVC light, a strong surface disinfection technology, is used worldwide to ensure not only environmental safety but also food safety. Several drawbacks associated with the use of mercury-containing UV lamps, especially human and environmental health risks, led to the Minamata Convention on Mercury, which prohibits the manufacture and import/export of products containing mercury. Therefore, light-emitting diode (LED)-based UVC irradiation, a new technology that is ecofriendly and represents an effective UV light source, has been researched recently. To date, however, there has been no report describing pulsed UVC-LED irradiation for improvement of inactivation of foodborne pathogens, although much research regarding conventional pulsed xenon lamps has been published. In this investigation, we evaluated the enhanced bactericidal effect of a pulsed UVC-LED system, compared to continuous irradiation, and optimum conditions for maximizing the effect were determined. Also, the differences in inactivation between pulsed and continuous UVC-LED irradiation were determined by inactivation mechanism analyses. The combination of 20-Hz frequency and 50% duty ratio for pulsed UVC-LED irradiation achieved 4- to 5-log-unit reductions of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes; this combination showed the greatest bactericidal effect among various treatment conditions using 2 or 5 mJ/cm² In mechanism assessments, membrane integrity (propidium iodide uptake) was not affected by UVC-LED treatment but membrane potential [bis-(1,3-dibutylbarbituric acid)trimethine oxonol [DiBAC₄(3)] accumulation] showed significantly different values when pulsed and continuous treatments were compared. Changes in membrane lipid peroxidation and respiratory enzyme activity were attributed to generation of more reactive oxygen species by pulsed UVC-LED irradiation.IMPORTANCE In 2013, the United Nations Environment Programme convened the Minamata Convention on Mercury, which prohibits trade in mercury-containing products in order to ensure human health. It will be effectuated in 2020; use of low-pressure mercury lamps will be discontinued and a new UV light source selected to replace the conventional technology. In this regard, UVC-LEDs have been developed and the fundamental inactivating effect has been researched. However, a pulsed UVC-LED system has not been studied, because of the difficulty of generating a UVC-LED pulse wave. An optical chopper system that physically divides the light with an adjustable blade, with personalized frequency and duty ratio settings, was introduced for generation of pulsed UVC-LED irradiation. This study elucidated the efficacy of a pulsed UVC-LED system and investigated its enhanced bactericidal effect in mechanism analyses.

Role of ethanolic extract of Morus alba leaves on some biochemical and hematological alterations in irradiated male rats

PURPOSE

The present study aimed to evaluate the protective role of "Morus alba Linn (Family: Moraceae) commonly known as mulberry" leaves extract against hazardous effects of gamma rays in male rats.

MATERIALS AND METHODS

Thirty six male albino rats were divided into six groups (six rats/group); (1) control group received 1 ml distilled water, (2) low dose of extract (100 mg/kg) group treated daily with low oral dose of ethanolic extract of mulberry leaves (100 mg/kg body weight (b.wt.)) for 21 consecutive days, (3) high dose of extract (200 mg/kg) group treated daily with high oral dose of ethanolic extract of mulberry leaves (200 mg/kg b.wt.) for the same period, (4) irradiated group rats were subjected to whole body gamma irradiation at a shot dose of 7 Gy, (5) low dose of extract + irradiated group treated daily with low oral dose of ethanolic extract of mulberry leaves (100 mg/kg b.wt.) for 21 consecutive days then rats were exposed to gamma irradiation at a single dose of 7 Gy, (6) high dose of extract + irradiation group treated daily with high oral dose of ethanolic extract of mulberry leaves (200 mg/kg b.wt.) for 21 consecutive days then rats were exposed to gamma irradiation at a single dose of 7 Gy. Rats were sacrificed 1, 7, 15 days post gamma irradiation in all groups. Blood samples were taken at three intervals time in the six groups.

RESULTS

The results showed that whole body irradiation of rats induced significant decrease (p < 0.05) in red blood cells (RBCs), hemoglobin (Hb), hematocrit percentage (HCT%), platelet, white blood cells (WBCs), lymphocytes, neutrophils, serum glucose-6-phosphate dehydrogenase (G-6-PD) and insulin. The data also showed significant increase (p < 0.05) in serum total lipids, phospholipids, cholesterol, triglycerides, lactate dehydrogenase (LDH), creatine kinase (CK), and plasma glucose. Administration of mulberry leaves extract, either low or high concentrations to rats prior to irradiation caused significant improvement in the studied parameters.

CONCLUSIONS

Mulberry leaves extract prior to exposure to gamma irradiation has radio protector against hazardous effect of irradiation in male rats.

Synergism between luteolin and sulforaphane in anti-inflammation

Luteolin and sulforaphane are well-known food bioactives with anti-inflammatory properties. In this study, we demonstrated the synergistic interactions between luteolin and sulforaphane against lipopolysaccharide-induced inflammation in macrophages.

Zebrafish phosvitin is an antioxidant with non-cytotoxic activity

Antioxidants, or anti-oxidant agents, have attracted a great deal of attention in recent years because of their roles in prevention of chronic diseases and utilization as preservatives in food and cosmetics. In this study, we clearly demonstrated that zebrafish recombinant phosvitin (rPv) is an antioxidant agent capable of inhibiting the oxidation of the linoleic acid, and scavenging the 2,2-diphenyl-1-picrylhydrazyl radical. We also showed that zebrafish rPv is a cellular antioxidant capable of protecting radical-mediated oxidation of cellular biomolecules. Importantly, zebrafish rPv is non-cytotoxic to murine macrophage RAW264.7 cells. It is the first report that showed the antioxidant activities of Pv in fishes, suggesting that zebrafish Pv can be an important antioxidant, which can be used as preservatives in food and cosmetics and even as supplementary mediator in different diseased states.

Chitooligosaccharide and its derivatives: preparation and biological applications

Chitin is a natural polysaccharide of major importance. This biopolymer is synthesized by an enormous number of living organisms; considering the amount of chitin produced annually in the world, it is the most abundant polymer after cellulose. The most important derivative of chitin is chitosan, obtained by partial deacetylation of chitin under alkaline conditions or by enzymatic hydrolysis. Chitin and chitosan are known to have important functional activities but poor solubility makes them difficult to use in food and biomedicinal applications. Chitooligosaccharides (COS) are the degraded products of chitosan or chitin prepared by enzymatic or chemical hydrolysis of chitosan. The greater solubility and low viscosity of COS have attracted the interest of many researchers to utilize COS and their derivatives for various biomedical applications. In light of the recent interest in the biomedical applications of chitin, chitosan, and their derivatives, this review focuses on the preparation and biological activities of chitin, chitosan, COS, and their derivatives.

Antioxidant effects of chitin, chitosan, and their derivatives

Chitin, chitosan, and their derivatives are considered to promote diverse activities, including antioxidant, antihypertensive, anti-inflammatory, anticoagulant, antitumor and anticancer, antimicrobial, hypocholesterolemic, and antidiabetic effects, one of the most crucial of which is the antioxidant effect. By modulating and improving physiological functions, chitin, chitosan, and their derivatives may provide novel therapeutic applications for the prevention or treatment of chronic diseases. Antioxidant activity of chitin, chitosan, and their derivatives can be attributed to in vitro and in vivo free radical-scavenging activities. Antioxidant effect of chitin, chitosan, and their derivatives may be used as functional ingredients in food formulations to promote consumer health and to improve the shelf life of food products. This chapter presents an overview of the antioxidant activity of chitin, chitosan, and their derivatives with the potential utilization in the food and pharmaceutical industries.

The chromene sargachromanol E inhibits ultraviolet A-induced ageing of skin in human dermal fibroblasts

BACKGROUND

Skin ageing is influenced by environmental factors such as ultraviolet (UV) radiation. The effects of UV radiation on skin functions should be investigated using human in vitro models to understand the mechanisms of skin ageing. Additionally, marine algae provide a valuable source for identifying and extracting biologically active substances.

OBJECTIVES

In this study, sargachromanol E was isolated from a marine brown alga, Sargassum horneri, and its inhibitory effect on skin ageing was investigated using UVA-irradiated dermal fibroblasts.

METHODS

Formation of intracellular reactive oxygen species (ROS), lipid peroxidation and protein oxidation induced by UVA irradiation were investigated in UVA-irradiated human dermal fibroblasts. The levels of matrix metalloproteinases (MMPs) were determined by reverse-transcriptase polymerase chain reaction and Western blot analysis.

RESULTS

Sargachromanol E did not exhibit any significant cytotoxicity or phototoxicity in UVA-exposed dermal fibroblasts. Additionally, sargachromanol E suppressed intracellular formation of ROS, membrane protein oxidation, lipid peroxidation and expression of collagenases such as MMP-1, MMP-2 and MMP-9, all of which are caused by UVA exposure. It was further found that these inhibitions were related to an increase in the expression of the tissue inhibitor of metalloproteinase (TIMP) genes, TIMP1 and TIMP2. Moreover, we have shown that the transcriptional activation of activator protein 1 (AP-1) signalling caused by UVA irradiation was inhibited by treatment with sargachromanol E.

CONCLUSIONS

This study suggests that UVA irradiation modulates MMP expression via the transcriptional activation of AP-1 signalling, whereas treatment with sargachromanol E protected cell damage caused by UVA irradiation.

Peptide isolated from Japanese flounder skin gelatin protects against cellular oxidative damage

Gelatin was extracted from the skin of Japanese flounder ( Palatichtys olivaceus ) and was subjected to enzymatic hydrolysis. The peptic hydrolysate resulted in a potent antioxidative peptide Gly-Gly-Phe-Asp-Met-Gly (582 Da), which bears +12.61 kcal/mol hydrophobicity. The antioxidative potential of the peptide was characterized by analyzing the protective effect of the peptide on reactive oxygen species (ROS)-mediated intracellular macromolecule damage. It was found that the peptide is a potent scavenger of intracellular ROS, thereby protecting the radical-mediated damage of membrane lipids, proteins, and DNA. Moreover, the peptide is capable of upregulating the expression of inherent antioxidative enzymes, superoxide dismutase-1, glutathione, and catalase. Collectively, it can be concluded that Japanese flounder skin, a processing byproduct of filleting, can be effectively used to produce a bioactive peptide with potent antioxidant capacity.

Protective effects of aminoethyl-chitooligosaccharides against oxidative stress in mouse macrophage RAW 264.7 cells

The aim of this study is to investigate the inhibitory effects of aminoethyl-chitooligosaccharides (AE-COS) on oxidative stress in mouse macrophages (RAW 264.7 cells). The inhibitory effects of AE-COS on DNA and protein oxidation were studied in RAW 264.7 cells. Furthermore, free radical scavenging effect of AE-COS were determined in RAW264.7 cells by 2',7'-dichlorofluorescein (DCF) intensity and intracellular glutathione (GSH) level. AE-COS also inhibited myeloperoxidase (MPO) activity in human myeloid cells (HL-60). These results suggest that AE-COS acts as a potential free radical scavenger in RAW 264.7 cells.

Applications of marine nutraceuticals in dairy products

The concept of nutraceutical has been derived by coining the terms "nutrition" and "pharmaceutical". In this context, active substances with pharmaceutical properties are delivered to the humans through food-based approaches to prevent or treat certain disease conditions. Since the natural sources are recognized as safe for human consumption, the active substances produced in the diverse group of marine organisms have a wide role in the nutraceutical industry. These marine-derived active ingredients include certain polysaccharides, polyphenols, bioactive peptides, polyunsaturated fatty acids, and carotenoids which are known to have anticancer, anti-inflammatory, antioxidant, antiobese, hypocholesteroleic, antimicrobial, prebiotic, and probiotic activity enabling them to be applied as nutraceuticals. As the dairy products are widely accepted by the consumers, the delivering of nutraceuticals through dairy products have received a greater attention of the dairy industry. Since the incorporation of marine-derived active ingredients into the dairy products have caused minimal changes in the physico-chemical properties of the final product, marine-derived substances have been widely applied and have the potential to be applied as nutraceuticals in the dairy industry.

Free radical scavenging and angiotensin-I converting enzyme inhibitory peptides from Pacific cod (Gadus macrocephalus) skin gelatin

Potent antioxidative peptides were purified from Pacific cod (Gadus macrocephalus) skin gelatin using alcalase, neutrase, papain, trypsin, pepsin, and α-chymotrypsin. Among them, the papain hydrolysate exhibited the highest antioxidant activity. Therefore, it was further purified and obtained two peptides with amino acid sequences of Thr-Cys-Ser-Pro (388 Da) and Thr-Gly-Gly-Gly-Asn-Val (485.5 Da). The antioxidant activity of the purified peptides was performed by electron spin resonance technique. Moreover, their intracellular free radical scavenging activity using 2',7'-dichlorofluorescin diacetate and the protective effect against oxidation-induced DNA damage were evaluated in mouse macrophages (RAW 264.7 cells). Furthermore, both peptides have shown potential angiotensin-I converting enzyme inhibitory effect. The present study demonstrated that the peptides derived from Pacific cod (G. macrocephalus) skin gelatin could be used in the food industry as functional ingredients with potent antioxidative and antihypertensive benefits.

Applications of chitin and its derivatives in biological medicine

Chitin and its derivatives-as a potential resource as well as multiple functional substrates-have generated attractive interest in various fields such as biomedical, pharmaceutical, food and environmental industries, since the first isolation of chitin in 1811. Moreover, chitosan and its chitooligosaccharides (COS) are degraded products of chitin through enzymatic and acidic hydrolysis processes; and COS, in particular, is well suited for potential biological application, due to the biocompatibility and nontoxic nature of chitosan. In this review, we investigate the current bioactivities of chitin derivatives, which are all correlated with their biomedical properties. Several new and cutting edge insights here may provide a molecular basis for the mechanism of chitin, and hence may aid its use for medical and pharmaceutical applications.

Effect of Sargassum thunbergii on ROS mediated oxidative damage and identification of polyunsaturated fatty acid components

In this study, we examined protective effect of Sargassum thunbergii on reactive oxygen species (ROS) mediated oxidative stress in cellular systems. In addition, polyunsaturated fatty acids from S. thunbergii were identified and quantified by gas chromatography mass spectroscopy. Intracellular ROS levels were measured using a oxidation sensitive dye, 2',7'-dichlorofluorescein diacetate (DCFH-DA). Treatment with S. thunbergii significantly reduced intracellular ROS mediated cell damage and inhibited myeloperoxidase (MPO) activity assessed in tumor necrosis factor-alpha (TNF-alpha) stimulated human monocytic leukemia in a concentration-dependent manner. Moreover, antioxidative mechanisms by S. thunbergii were evaluated by measuring the expression levels of antioxidative enzymes such as superoxide dismutase (SOD-1), catalase, glutathione peroxidase and glutathione reductase. SOD-1 and glutathione reductase were up-regulated by S. thunbergii. Furthermore, S. thunbergii contains polyunsaturated fatty acids such as arachidonic acid, arachidic acid, palmitic acid, elaidic acid, linoleic acid, stearic acid and cis-5,8,11,14,17-eicosanoic acid. Therefore, these results suggested that S. thunbergii has nutraceutical effectiveness in prevention of ROS-induced tissue damage and potential natural antioxidant related to oxidative stress, which can be traceable to polyunsaturated fatty acids contained in S. thunbergii.

Antioxidant effects of a dietary supplement: reduction of indices of oxidative stress in normal subjects by water-soluble chitosan

The effect of water-soluble chitosan, a natural polymer derived from chitin, on indices of oxidative stress was investigated in normal volunteers. Treatment with chitosan for 4 weeks produced a significant decrease in levels of plasma glucose, atherogenic index and led to increase in high density lipoprotein cholesterol (HDL). Chitosan treatment also lowered the ratio of oxidized to reduced albumin and increased total plasma antioxidant activity (TPA). There was good correlation between TPA and oxidized albumin ratio. The results indicate that oxidized albumin ratio represents a potentially useful marker of oxidative stress. In in vitro studies, albumin carbonyls and hydroperoxides were significantly decreased in a time-dependent manner in the presence of chitosan, compared with controls (p<0.05). Chitosan also reduced two stable radicals in a dose- and time-dependent manner. The results suggest that chitosan has a direct antioxidant activity in systemic circulation by lowering the indices of oxidative stress in both in vitro and in vivo studies. This may confer benefits additional to the reduction in plasma carbohydrate and increase in HDL levels. It may also inhibit oxidation of serum albumin commonly observed in patients undergoing hemodialysis, resulting in reduction of oxidative stress associated with uremia.

Antioxidant effects of phlorotannins isolated from Ishige okamurae in free radical mediated oxidative systems

Three phlorotannins, including phloroglucinol, diphlorethohydroxycarmalol, and 6,6'-bieckol, were isolated from Ishige okamurae by column chromatography. The structures of the phlorotannins were determined on the basis of spectroscopic analysis, including NMR and mass spectrometry (MS) techniques. Antioxidant effects of phlorotannins were measured by direct free radical scavenging activities using the electron spin resonance spectrometry (ESR) technique and cellular systems in vitro. The results indicated that diphlorethohydroxycarmalol and 6,6'-bieckol showed potential radical scavenging activities against the 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, alkyl, and superoxide radicals. Moreover, no cytotoxicities of the phlorotannins on human fetal lung fibroblasts cell line (MRC-5), mouse macrophages cell line (RAW264.7), and human leukemic cell line (HL-60) were observed. In addition, diphlorethohydroxycarmalol and 6,6'-bieckol significantly reduced the intracellular reactive oxygen species level assessed by 2',7'-dichlorofluorescein diacetate (DCFH-DA) assay in RAW264.7 cells, and myeloperoxide (MPO) activity in HL-60 cells and radical-mediated oxidation of cell membrane proteins in RAW264.7 cells were dose-dependently inhibited in the presence of diphlorethohydroxycarmalol and 6,6'-bieckol. In conclusion, these results suggested that phlorotannins could be used as novel functional foodstuffs or antioxidants in the cosmetic and drug industries.