Mahinda Senevirathne

ANTIOXIDANT POTENTIAL OF ECKLONIA CAVA ON REACTIVE OXYGEN SPECIES SCAVENGING, METAL CHELATING, REDUCING POWER AND LIPID PEROXIDATION INHIBITION

The antioxidative potential of different fractions (respective organic and aqueous fractions of n-hexane, chloroform and ethyl acetate) of 70% methanol extract of Ecklonia cava(a brown seaweed) was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion, hydrogen peroxide, hydroxyl radical, nitric oxide, ferrous ion chelating, reducing power and lipid peroxidation inhibition (conjugated diene hydroperoxide and thiobarbituric acid-reactive substances production) assays. The 70% methanol extract showed significant (p< 0.05) activities in all antioxidant assays and contained a high level of total phenolic content. It was observed that the level of hydrophilic phenolic content was higher than that of hydrophobics. Among those organic solvent fractions, ethyl acetate fraction exhibited significant activities due to the highest level of total phenolic content and their IC50 values were 0.013mg/mL, 0.009mg/mL and 0.33mg/mL in DPPH, hydrogen peroxide and nitric oxide radical inhibition, respectively. These activities were superior to those of a commercial synthetic and natural antioxidants tested. The aqueous chloroform and ethyl acetate fractions also exhibited significant (p< 0.05) activities in reactive oxygen species (ROS) scavenging and metal chelating, attributed to the high amount of hydrophilic phenolics. Moreover, E. cava extracts showed strong reducing power and a notable capacity to suppress lipid peroxidation.

Factors affecting anti-inflammatory effect of chitooligosaccharides in lipopolysaccharides-induced RAW264.7 macrophage cells.

In this study, factors affecting anti-inflammatory effect of chitooligosaccharides (COSs) in lipopolysaccharides (LPS)-induced RAW264.7 macrophage cells were investigated. The inhibition of NO secretion by COSs revealed that 90-COSs (90% N-deacetylation) significantly inhibited NO secretion than those of 50-COSs (50% N-deacetylation), and 90-HMWCOS (5000-10,000Da) in the 90-COSs showed the highest inhibition activity. Furthermore, 90-HMWCOSs also found to inhibit LPS-stimulated production of PGE(2), TNF-alpha and IL-6, as well as the expression of iNOS, COX-2, TNF-alpha, and IL-6. These results suggested that 90-HMWCOS may have anti-inflammatory effect via down-regulation of transcriptional and translational expression levels of TNF-alpha, IL-6 and iNOS and COX-2.

Protective effect of fermented sea tangle against ethanol and carbon tetrachloride-induced hepatic damage in Sprague-Dawley rats.

Sea tangle has long been used as Korean folk remedy to promote material health, and is one of the popular dietary supplement. This study was designed to evaluate the protective effect of fermented sea tangle (FST) against ethanol and carbon tetrachloride (CCl(4))-induced hepatotoxicity in rats. Sprague-Dawley rats were orally treated with FST (25, 250, 2500 mg/kg/day) with administration of ethanol (5 mL/kg) for 13 weeks and the single intraperitoneal (i.p.) dose of 50% CCl(4) (5 mL/kg/day, CCl(4) in olive oil) at 12 week, and repeated i.p. dose of 20% CCl(4) (2 mL/kg/day) for 1 week. Hepatotoxicity was evaluated by measuring the serum levels of glutamic pyruvate transaminase (GPT), gamma glutamyl transpeptidase (gamma-GT) and malondialdehyde (MDA) as well as the tissue levels of antioxidant enzyme such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Ethanol and CCl(4)-induced the rat liver damage, and significantly increased (p<0.05) the GPT, gamma-GT and MDA levels, and decreased the SOD, CAT and GPx levels. However, treatment with FST could decrease serum GPT, gamma-GT, and MDA levels significantly in plasma, and increase the activities of SOD, CAT, and GPx in liver tissues compared with ethanol and CCl(4)-treated group.

Utilization of Seafood Processing By-products: Medicinal Applications

Large amount of underutilized by-products are generated from the seafood processing plants annually. Consequently, researches have been initiated to investigate those discarded materials and have identified a number of bioactive compounds including bioactive peptides, collagen and gelatin, oligosaccharides, fatty acids, enzymes, calcium, water-soluble minerals, and biopolymers. Bioactive peptides derived from fish by-products have shown various biological activities including antihypertensive and antioxidant activities and hence may be a potential material for biomedical and food industries. Collagen and gelatin are currently used in diverse fields including food, cosmetic, and biomedical industries. Other than that, they are promising drug carriers for the treatment of cancer. Many studies have reported that chitin, chitosan, and their derivatives possess biologically active polysaccharides and hence they are potential agents for many applications. Further, those compounds have also showed potential activities such as antioxidant, antibacterial, antiviral, antihypertensive, anticancer, etc. Hence, seafood by-products are valuable natural resources that show range of functionalities and hence potential materials for biomedical and nutraceutical industries.

Utilization of Seafood Processing By-products

Large amount of underutilized by-products are generated from the seafood processing plants annually. Consequently, researches have been initiated to investigate those discarded materials and have identified a number of bioactive compounds including bioactive peptides, collagen and gelatin, oligosaccharides, fatty acids, enzymes, calcium, water-soluble minerals, and biopolymers. Bioactive peptides derived from fish by-products have shown various biological activities including antihypertensive and antioxidant activities and hence may be a potential material for biomedical and food industries. Collagen and gelatin are currently used in diverse fields including food, cosmetic, and biomedical industries. Other than that, they are promising drug carriers for the treatment of cancer. Many studies have reported that chitin, chitosan, and their derivatives possess biologically active polysaccharides and hence they are potential agents for many applications. Further, those compounds have also showed potential activities such as antioxidant, antibacterial, antiviral, antihypertensive, anticancer, etc. Hence, seafood by-products are valuable natural resources that show range of functionalities and hence potential materials for biomedical and nutraceutical industries.

Development of bioactive peptides from fish proteins and their health promoting ability.

Great amount of marine fish species have been identified with potential nutraceutical and medicinal values. Consequently, a number of bioactive compounds have been identified including fish muscle proteins, peptides, collagen and gelatin, fish oil, fish bone. Bioactive peptides derived from various fish muscle proteins have shown various biological activities including antihypertensive, antibacterial, anticoagulant, anti-inflammatory, and antioxidant activities, and hence they may be a potential material for biomedical and food industries. Further, they are commonly used in medical and pharmaceutical industries as carrier molecules for drugs, proteins, and genes. Hence, fish muscle protein-derived peptides are valuable natural resources that can be potential material for biomedical, nutraceutical, and food industries.

Synthesis of phenolic acid conjugated chitooligosaccharides and evaluation of their antioxidant activity.

In this study, eight kinds of phenolic acid conjugated chitooligosaccharides (PA-c-COSs) with different substitution groups, including p-hydroxyl {hydroxybenzoic acid-c-COS (HBA-c-COS), p-coumaric acid-c-COS (PCA-c-COS)}, 3,4-dihydroxyl {protocatechuic acid-c-COS (PTA-c-COS), caffeic acid-c-COS (CFA-c-COS)}, 3-methoxyl-4-hydroxyl {vanillic acid-c-COS (VNA-c-COS), ferulic acid-c-COS (FRA-c-COS)} and 3,5-dimethoxyl-4-hydroxy {syringic acid-c-COS (SRA-c-COS), sinapinic acid-c-COS (SNA-c-COS)}, were prepared by amide coupling reaction. Their antioxidant properties were evaluated using several in vitro models such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH) and nitric oxide (NO) radicals scavenging and reducing power assays. The structures of the synthesized compounds were confirmed by UV, FT-IR and (1)H NMR data. CFA-c-COS showed 81.6% and 89.8% scavenging against DPPH and NO radical formation, respectively. CFA-c-COS also showed higher reducing power and hydroxyl radical scavenging activity compared to those of other compounds. Hence, CFA-c-COS can be a potential antioxidant compound.

Protective effect of enzymatic hydrolysates from highbush blueberry (Vaccinium corymbosum L.) against hydrogen peroxide-induced oxidative damage in Chinese hamster lung fibroblast cell line

Blueberry was enzymatically hydrolyzed using selected commercial food grade carbohydrases (AMG, Celluclast, Termamyl, Ultraflo and Viscozyme) and proteases (Alcalase, Flavourzyme, Kojizyme, Neutrase and Protamex) to obtain water soluble compounds, and their protective effect was investigated against H2O2-induced damage in Chinese hamster lung fibroblast cell line (V79-4) via various published methods. Both AMG and Alcalase hydrolysates showed higher total phenolic content as well as higher cell viability and ROS scavenging activities, and hence, selected for further antioxidant assays. Both AMG and Alcalase hydrolysates also showed higher protective effects against lipid peroxidation, DNA damage and apoptotic body formation in a dose-dependent fashion. Thus, the results indicated that water soluble compounds obtained by enzymatic hydrolysis of blueberry possess good antioxidant activity against H2O2-induced cell damage in vitro.

Antibacterial effect of citrus press-cakes dried by high speed and far-infrared radiation drying methods

In this study, the antibacterial effect was evaluated to determine the benefits of high speed drying (HSD) and far-infrared radiation drying (FIR) compared to the freeze drying (FD) method. Citrus press-cakes (CPCs) are released as a by-product in the citrus processing industry. Previous studies have shown that the HSD and FIR drying methods are much more economical for drying time and mass drying than those of FD, even though FD is the most qualified drying method. The disk diffusion assay was conducted, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined with methanol extracts of the dried CPCs against 11 fish and five food-related pathogenic bacteria. The disk diffusion results indicated that the CPCs dried by HSD, FIR, and FD prevented growth of all tested bacteria almost identically. The MIC and MBC results showed a range from 0.5-8.0 mg/mL and 1.0-16.0 mg/mL respectively. Scanning electron microscopy indicated that the extracts changed the morphology of the bacteria cell wall, leading to destruction. These results suggest that CPCs dried by HSD and FIR showed strong antibacterial activity against pathogenic bacteria and are more useful drying methods than that of the classic FD method in CPCs utilization.

Membrane Bioreactor Technology for the Development of Functional Materials from Sea-Food Processing Wastes and Their Potential Health Benefits

Sea-food processing wastes and underutilized species of fish are a potential source of functional and bioactive compounds. A large number of bioactive substances can be produced through enzyme-mediated hydrolysis. Suitable enzymes and the appropriate bioreactor system are needed to incubate the waste materials. Membrane separation is a useful technique to extract, concentrate, separate or fractionate the compounds. The use of membrane bioreactors to integrate a reaction vessel with a membrane separation unit is emerging as a beneficial method for producing bioactive materials such as peptides, chitooligosaccharides and polyunsaturated fatty acids from diverse seafood-related wastes. These bioactive compounds from membrane bioreactor technology show diverse biological activities such as antihypertensive, antimicrobial, antitumor, anticoagulant, antioxidant and radical scavenging properties. This review discusses the application of membrane bioreactor technology for the production of value-added functional materials from sea-food processing wastes and their biological activities in relation to health benefits.