Antioxidant Activity of Hydrolysates and Peptide Fractions of Nemipterus japonicus and Exocoetus volitans Muscle

The focus of the study was to investigate the antioxidant activity of hydrolyzed muscle protein of Nemipterus japonicus and Exocoetus volitans. The trypsin protein hydrolysates of both fish showed maximum free radical scavenging potential and lipid peroxidation inhibition. Furthermore, it was purified by chromatographic methods followed by the lipid peroxidation inhibition; free radical scavenging assay was performed before and after purification. The purified peptide fractions of N. japonicus and E. volitans exhibited higher activity against polyunsaturated fatty acids (PUFA) peroxidation which was similar to natural antioxidants like α-tocopherol. Free radical scavenging potencies were measured by electron spin resonance technique (ESR). The purified peptide of E. volitans quenched free radicals (DPPH, hydroxyl, and superoxide) slightly more than N. japonicus. The amino acid composition of both fish protein hydrolysates showed variations in their ratio. The purified peptides were tested for cell cytotoxicity for Vero (kidney epithelial cells of the African Green Monkey) and Hep G₂ (human hepatocellular liver carcinoma) cell lines. It was found that peptides did not show any cytotoxic effect for Vero cell lines and exerted a significant antiproliferative effect on Hep G₂ cell lines.     

Antioxidant Activity of Brown Seaweeds

Antioxidant potential of three brown seaweeds, Anthophycus longifolius, Sargassum plagiophyllum, and Sargassum myriocystum, obtained from the Gulf of Mannar region of India were evaluated utilizing different in vitro systems. Ethyl acetate (EtOAc) fraction of Anthophycus longifolius registered significantly greater hydroxyl radical scavenging ability (IC₅₀ 0.19 mg/mL) and was effective in stabilizing the 2,2′-azino-bis-3-ethylbenzothiozoline-6-sulfonic acid (IC₅₀ 1.23 mg/mL) and 1,1-diphenyl-2-picryl-hydrazil (DPPH) radicals (IC₅₀ 0.48 mg/mL) (p < 0.05). No significant differences in hydrogen peroxide (H₂O₂) scavenging and ferrous ion chelating properties of the EtOAc extracts of the seaweeds were apparent. The utilities of the reverse-phase high-performance liquid chromatography (RP-HPLC) method hyphenated to diode-array detection for analyzing the fingerprints of phenolic constituents in the solvent extracts and fractions of the seaweeds were denoted. High-performance liquid chromatographic analysis indicated the presence of phenolic acids in the solvent extracts of seaweeds. This study demonstrated the potential use of A. longifolius as candidate species to be used as a nutritional food supplement/functional foods to increase the shelf life of food items for human consumption.     

Antioxidant Properties of Protein Hydrolysate Obtained from Oyster Saccostrea cucullata (Born, 1778)

The antioxidant activities of enzymatically hydrolyzed (protease from Bacillus cereus SU12) oyster (Saccostrea cucullata) protein were studied. The hydrolysate exhibited a strong antioxidant potential in 1, 1-diphenyl-2-picrylhydrazyl (DPPH, 85.7 ± 0.37%), followed by hydrogen peroxide radical scavenging activity (81.6 ± 0.3%), hydroxyl radical scavenging activity (79.32 ± 0.6%), and reducing power assay (2.63 ± 0.2 OD at 700 nm) at a concentration of 1 mg/mL. Due to the high antioxidant potential, the hydrolysate was purified in Sephadex G-25 gel filtration chromatography. The active peptide fraction was identified by DPPH and reducing power assay. The amino acid content of the purified active peptide fraction was analyzed by high performance liquid chromatography. The active fraction contained a good quantity of both essential and nonessential amino acids. The present study revealed that oyster (S. cucullata) protein hydrolysate is a potential source for natural antioxidants.     

Antioxidant Properties and the Preservative Effect of Whole Radish Extract on Quality of Deccan Mahseer (Tor khudree) Steaks during Chilled Storage

ABSTRACT

The effect of dip treatment with solvent-free whole radish extract (WRE) on quality characteristics of Deccan mahseer steaks was evaluated during the chilled storage. In-vitro antioxidant activities of the extract were evaluated based on total phenolic and flavonoid contents, DPPH radical scavenging activity, and metal chelating ability prior to the dip treatment. The quality parameters, including total volatile base nitrogen (TVB-N), trimethylamine nitrogen (TMA-N), and free fatty acid (FFA), were significantly (p < .05) reduced in WRE treated steaks compared to the control (CT) steaks. WRE treatment of fish steaks significantly controlled the lipid oxidation parameters of thiobarbituric acid reactive substances (TBARS) and peroxide value (PV). Total plate count (TPC) of CT sample was higher than the treated sample and remained within the limit of 7 log₁₀ cfu/g at the end of storage. As per the sensory analysis, shelf life of Deccan mahseer was determined to be 15 days for WRE treated steaks and 9 days for control steaks during chill storage. Based on the results, it can be concluded that WRE treatment can limit the progress of fish spoilage bacteria in fish steaks and can be used as a substitute for synthetic additives.     

Changes in the Antioxidant Potential of Nori Sheets During in vitro Digestion with Pepsin

Nori, the dried sheets of Porphyra, is a popular edible seaweed and a potential source of high quality protein, vitamins, and minerals. In the present study, the antioxidant potential of Nori has been investigated. For this purpose, an aqueous extract was obtained by soaking powdered Nori in KCl-HCl buffer and hydrolyzing it with pepsin. The antioxidant activity of aqueous extract of crude as well as pepsin hydrolyzate was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, reducing power, total antioxidant capacity and lipid peroxidation by thiobarbituric acid reactive substances (TBARS) and compared with L-ascorbic acid. After hydrolysis, the scavenging ability and inhibition of lipid per oxide was doubled, and a sevenfold increase in reducing power activity was observed. The small molecular weight fractions (F-II) of hydrolyzate obtained after gel filtration showed further increase in the activity. These results demonstrate that hydrolysis produces better antioxidants that could be used as an alternative to synthetic antioxidants.     

Chemical Compositions and Antioxidant Activities of a Specialty Aquatic Vegetable Nymphoides hydrophylla in Taiwan

Nymphoides hydrophylla (NH), a lesser known aquatic vegetable, is a popular dish among the Hakka community in Taiwan. This study aimed to examine the proximate and polyphenolic compositions of NH and evaluate its antioxidant activities using various antioxidant assays. Results showed that the moisture, crude protein, crude fat, carbohydrate (crude fiber), and ash contents of fresh NH were 89.46, 0.46, 0.47, 4.11 (3.65), and 5.50%, respectively. In the antioxidant studies, the NH ethanolic extract (NH-E) exhibited higher antioxidant activities than the aqueous extract (NH-H) in the antilipid peroxidation, reducing power, metal chelation, and 2,2?-azino-bis(3-ethylbenthiazoline-6-sulfonic acid) or ABTS radical scavenging assays, while NH-H possessed more potent activity in the superoxide and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. Compared with NH-H (6.86 mg/g for total flavonoids and 48.83 mg/g for total phenolics), NH-E showed a higher content of total flavonoids (197.21 mg/g) and total phenolics (79.43 mg/g). High-performance liquid chromatography (HPLC) analysis showed that the main difference between NH-H and NH-E polyphenolic contents was derived from the concentrations of kaempferol and quercetin.     

Chemical Characterization,Temperature Stability,and Enzymatic Studies on Edible Marine Algae Kappaphycus alvarezii (Doty)

Antioxidant activity of the marine alga Kappaphycus alvarezii was investigated. Methanol, acetone, petroleum ether, aqueous methanol, ethyl acetate, and chloroform extracts (1 mg/mL) of K. alvarezii were tested for their 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The values were compared with those of Vitamin C and butylated hydroxytoluene (BHT). Extracts showing positive results, when tested for DPPH free radical scavenging, were examined for dose effect, in-vivo hydrogen peroxide (H₂O₂) and hydroxyl radical scavenging assays. All extracts showed dose-dependent DPPH scavenging and significant hydroxyl radical scavenging activities (> 82.6%). The acetone, aqueous methanol, and methanol extracts of K. alvarezii showed the highest scavenging activity. Ethyl acetate extract showed a moderate activity of 62.9%. In the DPPH method, petroleum ether and hexane extracts showed less activity with IC₅₀ values of 118.58 ± 8.94 and 116.25 ± 7.14 μg/mL, respectively. Acetone, methanol, and ethyl acetate extracts exhibited IC₅₀ values of 57.32 ± 1.07, 61.31 ± 0.67, and 79.50 ± 1.59 μg/mL, respectively. K. alvarezii showed higher antioxidant activity in both in vitro and in vivo studies. Proton NMR studies revealed signals in the region 0.5 to 2.0 ppm suggesting the presence of steroidal identity in the extracts.     

二种海胆性腺的脂质组成及其抗氧化活性

为分析马粪海胆和光棘球海胆性腺的脂质组成和抗氧化活性,采用核磁共振和气相色谱—质谱技术对2种海胆性腺油脂的脂质成分和脂肪酸组成进行分析,并通过DPPH自由基清除法、羟基自由基清除法和超氧阴离子自由基清除法对其脂质的抗氧化活性进行研究。结果显示,马粪海胆和光棘球海胆性腺脂质均以甘油三酯和磷脂为主,胆固醇、胆固醇酯和游离脂肪酸含量较低。马粪海胆和光棘球海胆性腺总脂富含C20:4n-6和C20:5n-3,且二者总量分别占脂肪酸含量的35.88%和34.98%;同时2种海胆性腺的中性脂和极性脂的脂肪酸组成存在较大差异,中性脂以C14:0和C16:0等饱和脂肪酸为主,而极性脂以C20:4n-6和C20:5n-3等多不饱和脂肪酸为主。马粪海胆和光棘球海胆性腺脂质对DPPH自由基、羟基自由基和超氧阴离子自由基均具有较好的清除能力,DPPH自由基IC₅₀分别为2.75和1.98 mg/mL,羟基自由基IC₅₀分别为0.33和0.29 mg/mL,超氧阴离子自由基IC₅₀分别为0.33和0.31 mg/mL。研究表明,马粪海胆和光棘球海胆性腺脂质具有较高的营养价值和抗氧化活性,可作为C20:4n-6、C20:5n-3和磷脂等功能性脂质因子的重要膳食来源。     

Antioxidant and ACE Inhibitory Activities of Kawakawa (Euthynnus affinis) Protein Hydrolysate Produced by Skipjack Tuna Pepsin

ABSTRACT

Pepsin enzyme from skipjack tuna was extracted for the production of kawakawa (Euthynnus affinis) fish protein hydrolysate. Using ultra-fractionation, Kawakawa protein hydrolysates were separated into four different fractions, including fractioned protein hydrolysate I (FPH I) (< 1 kDa), FPH-II (1–3 kDa), FPH-III (3–10 kDa), and FPH-IV (> 10 kDa). The antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, inhibition of linoleic acid oxidation, reducing power tests, and chelating activity of metal ions. Results indicated that FPH II fraction peptides had higher antioxidant activity in comparison with the other fractions, followed by FPH I. Further, the fractions were evaluated for angiotensin converting enzyme (ACE) inhibition, and IC₅₀ value ranged from 0.45 to 1.86 mg/ml with higher activity in FPH I (IC₅₀ 0.45). Finally, the amino acid profile of different fractions was analyzed. The fractions exhibited significant amounts of hydrophobic amino acids, which could perform as hydrogen donors, frustrate the free radicals, and inhibit the ACE. The recovered pepsin from the viscera was used to produce hydrolysates with good biological activities. Peptides lower than 3 KDa had antioxidant activity as positive controls and significant ACE activity. These are very important findings that could be used to conduct further research in a preclinical study of these peptides.     

Optimization of Antioxidant Peptides Production from the Mantle of Cuttlefish (Sepia pharaonis) Using RSM and Fractionation

Persian Gulf cuttlefish mantles were hydrolyzed (CPH) using alcalase, and the optimal hydrolysis parameters were obtained for the highest degree of hydrolysis (DH) and strongest antioxidant (based on their ability to quench 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals) activity using response surface methodology (RSM). The predicted optimal parameters of DH and quenching DPPH radicals was: pH of 7.88, 50.2°C, 150 min, and enzyme to substrate ratio of 1.5%. The reducing power (RP) and ability of optimized peptides to quench ABTS radicals in a gastro-intestinal track model system increased during the intestinal stage, while scavenging ability against DPPH radicals dropped (P < 0.05). The oxidation of lipid was retarded in a lecithin-liposome model added with optimized CPH in a concentration dependent response. Ultrafiltration of optimized CPH showed that the 3–10 KDa fraction had the greatest DPPH radical scavenging activity, the 10–30 KDa fraction had the highest reducing power, and the <3 KDa fraction had the greatest ABTS radical scavenging activity.     

大眼金枪鱼头蛋白酶解物1 ku超滤组分的抗氧化活性及其理化性质

研究大眼金枪鱼头蛋白酶解物1 ku超滤组分体外的还原力、自由基清除能力及对衰老小鼠体内抗氧化能力的影响,分析1 ku超滤组分的一般成分、氨基酸组成及分子量分布,为进一步分离纯化金枪鱼头抗氧化肽提供基础。体外结果显示,1 ku超滤组分对羟基自由基、超氧阴离子和DPPH自由基的清除活性随浓度的增加而增强,IC50分别为1.38、0.73与0.93mg/mL,还原力也随浓度的增加而增大,在浓度为12.5 mg/mL时为0.763;体内结果显示,灌胃30 mg/kg的1 ku超滤组分连续42 d,D-半乳糖致衰老小鼠肝组织的超氧化物歧化酶(SOD)活性、肝组织和血清的谷胱甘肽过氧化物酶(GSH-PX)活性显著提高(P<0.05),血清丙二醛(MDA)含量显著降低(P<0.01);理化分析结果显示,1 ku超滤组分(干基计)蛋白质含量为96.40%,脂肪0.11%,灰分4.86%,疏水性氨基酸占氨基酸总量的35.8%,活性组分分子量在1 802~2 519 u和422~922 u。     

Biological Activities of Freshwater Algae,Spirogyra singularis Nordstedt

Spirogyra is commonly found as accessible algae in freshwater areas all over the world. Some medical uses have been reported from this genus. Biological activities of Spirogyra singularis were investigated employing eight in vitro assays. The extract showed different antioxidant activity. IC₅₀ for DPPH radical-scavenging was 4.71 ± 0.11 μg mL^?1. The extract showed very strong nitric oxide-scavenging activity with IC₅₀ = 77.3 ± 2.07 μg mL^?1, but its Fe²⁺ chelating ability was weak. The extract also exhibited high antioxidant activity in hemoglobin-induced linoleic acid peroxidation tests and scavenging of hydrogen peroxide. The extract also showed good antihemolytic activity. The total amount of phenolic content in the extract was determined as gallic acid equivalents, and total flavonoid content was calculated as quercetin equivalents. Biological activities may be attributed, at least in part, to the presence of phenol and flavonoid contents in the extract.     

Biochemical Properties and Stability of Antioxidative Activity of Half-Fin Anchovy (Setipinna taty) Fermented Product

The aim of this work was to investigate the biochemical properties of fermented product of half-fin anchovy (HAFP; Setipinna taty) made by Natto bacillus fermentation—including molecular weight distribution, amino acid composition, solubility, foaming, and emulsifying profiles. Furthermore, the influences of thermal processing, pH alteration, and in vitro simulated gastric and intestinal digestion on the antioxidative stability of HAFP in terms of the scavenging 1,1-diphenyl-2-picrylhydrazayl (DPPH) radical were evaluated. Results showed that HAFP contained small peptides (< 1,500 Da) and free amino acids. The amounts of essential amino acids and flavor amino acids were 155.219 and 178.636 mg/g of dry HAFP, respectively. Moreover, HAFP contained high levels of antioxidative and hydrophobic amino acids. In suitable pH values, HAFP exhibited good solubility, foaming, and emulsifying properties. The antioxidative activity of HAFP on the scavenging DPPH radical increased after thermal processing. Furthermore, the DPPH radical scavenging activity of HAFP was enhanced slightly or dramatically after being treated under pH values from 3 to 6, or in vitro simulated gastric and intestinal digestion. It can be concluded that HAFP could have potential application in foods as a natural antioxidative ingredient.     

Assessment of Bioactive Potential of Aqueous Protein Extracts from Diatoms Nitzschia laevis,Spirulina platensis,and Chlorella vulgaris

The bioactivities of protein extracts from Nitzschia laevis, Spirulina platensis, and Chlorella vulgaris were evaluated in vitro. Free radical scavenging potential, reducing power, oxygen radical absorbance capacity, superoxide anion radical, xanthine oxidase inhibition, and potential to inhibit angiotensin 1-converting enzyme (ACE) and acetylcholinesterase enzyme (AChE) were studied. Nitzschia protein extracts showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities, reducing power, and ACE inhibitory activity. Spirulina’s proteins showed the highest 2,2′-Azino-bis (3 ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging activity, xanthine oxidase, and AChE inhibition activities. Aqueous protein extracts from Nitzschia, Spirulina, and Chlorella showed in vitro antioxidant, anti-ACE, and anti-AChE activities, suggesting possible new sources of bioactive proteins of different phyla with nutraceutical and pharmaceutical potentials.     

Antioxidant Properties of Seven Cultivated and Natural Edible Seaweed Extracts from Taiwan

Seven species of cultivated and edible seaweeds found in Southern Taiwan—including Enteromorpha intestinalis, Monostorma nitidum, Ulva lactuca, Dictyopteris undulata, Sargassum hemiphyllum var. chinense, Laurencia intermedia, and Porphyra dentate—were used to determine their antioxidant activity by different extraction methods. All seaweeds were extracted using water at 90°C, sterilization at 121°C, homogenization, or enzymatic hydrolysis. Extracts were evaluated for their free radical-scavenging capacity using 1,1-diphenyl-2-pricrylhydrazyl (DPPH), their reducing power, and their superoxide anion scavenging activity. The DPPH-scavenging capacity of S. hemiphyllum var. chinense extracts produced by sterilization (98.59%), homogenization (94.72%), and carbohydrate-degrading enzyme treatment was higher than that of protease extracts, except for U. lactuca. The reducing power of S. hemiphyllum var. chinense water extracts and M. nitidum Viscozyme extracts was better than that of a commercial antioxidant. S. hemiphyllum var. chinense exhibited higher superoxide anion scavenging activity than the other species. The results demonstrate that different extracts of some of the seaweeds showed remarkable antioxidant activity in different assays. The results also provide important information for the marine food industry and suggest that seaweed might be a valuable source of natural antioxidants.     

Pomegranate (Punica granatum L.) Peel Extracts Inhibit Microbial Growth and Lipid Oxidation in Minced Shrimps Stored at 4°C

Pomegranate peel is inherited with diverse functional properties that improve storage stability and nutritional quality of edible goods. This research was aimed at evaluating antioxidant and antimicrobial properties of pomegranate peel hydro-alcoholic extracts and to determine in situ efficacy of extracts in controlling microbial growth and lipid oxidation of shrimp meat. The results suggest that pomegranate peel ethanolic extracts (PoPetx) have significantly higher (p < 0.05) phenolic contents, 169 mg GAE/100 g accompanied with 90% free radical scavenging activities. Contrary to the normal control, incorporation of PoPetx @ 2.0% (w/w) in minced shrimp meat increased thiobarbituric acid reactive species generation by 10% during 28 days of storage at 4°C. Supplementing PoPetx @ 0.5–2.0% (w/w) to shrimp meat has shown a comparable microbial inhibitory action against total plate counts and Staphylococcus spp. The study concludes that application of pomegranate peel extracts in minced shrimp is a viable strategy to preserve chemical and microbiological quality of shrimp and products of sea origin.     

Antioxidant Assessment of Schizochytrium Meal Protein Enzymatic Hydrolysate and Its Potential Application

Schizochytrium meal protein (SMP) extracted from Schizochytrium meal was hydrolyzed by flavourzyme. Response surface methodology (RSM) was used to optimize the extraction conditions for the protein extraction yield from Schizochytrium meal. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (DRSA) was used to evaluate the antioxidant activity of hydrolysates. The orthogonal test was used to investigate the effects of three independent variables, namely protease dosage, hydrolysis time, and pH. The optimum conditions obtained were as follows: protease dosage of 7%, hydrolysis time of 1.5 h, pH of 6, under which, DRSA at the concentration of 2 mg/mL was 89.38%. Aspartic and glutamic acid constituted approximately 26.32% of the total amino acids, and glutamic acid was the most abundant amino acid of Schizochytrium meal protein hydrolysate (SMPH) by amino acid composition analysis, which may have contributed to the scavenging activity of SMPH. Moreover, SMPH was made into chewable tablets with suitable formula and high humidity stability. These findings indicate that Schizochytrium meal can be reused as a raw material for preparation of antioxidant peptides.     

Effects on Lipid Oxidation and Bioactive Properties of Rainbow Trout Fillets Fed with Barley

Barley concentrations ranging from 0% to 32% were incorporated into rainbow trout (Oncorhynchus mykiss) diets. The effect of barley concentration on lipid peroxidation and antioxidant activity of fish fillets were analyzed. Results showed that the inclusion of barley in rainbow trout diets had an inhibitory effect on lipid oxidation, probably associated with certain bioactive compounds in barley that could interact with scavenging and reducing metabolites involved in lipid oxidation. Concentrations up to 8% of barley produced fish fillets with high antioxidant activity and higher levels of alpha-tocopherol.     

Evaluation of the Antioxidant Activity In Vitro and in Hippocampal HT-22 Cells System of Protein Hydrolysates of Common Carp (Cyprinus carpio) By-Product

Fish processing by-products may become more than 50% of the starting material. If mismanaged, these large quantities of discarded fish can create serious pollution problems and can also generate cost associated with their disposal. Enzymatic hydrolysis is one of the techniques that is currently being developed in order to recover and add value to these biomolecules. There is an increasing interest in natural antioxidants that are safer for consumers compared with synthetic antioxidants. In this study, common carp by-product was hydrolyzed using the enzymes Alcalase (A) and Protamex (P) to reach degrees of hydrolysis (DH) of 10 and 15%, respectively. Antioxidant capacity against peroxyl radicals (ACAP); 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging; and the measurement of intracellular reactive oxygen species (ROS) concentration after exposure to common carp protein hydrolysates were investigated. The results revealed that the hydrolysate A15 exhibited significantly (p < 0.05) higher antioxidant activity against the DPPH radical. A15 showed the highest in vitro antioxidant competence against peroxyl radicals, whereas P15 showed the lowest activity against peroxyl radicals (p < 0.05). Hydrolysates having the highest and the lowest in vitro antioxidant activity (A15 and P15, respectively) were selected for the determination of antioxidant activity in the HT-22 cells system. Measurement of intracellular ROS concentration revealed that P15 at the concentration of 1.25 mg/mL significantly (p < 0.05) reduced the intracellular ROS concentration. These results showed that common carp by-product protein hydrolysates are a source of antioxidant peptides with a high potential for food and pharmaceutical industries to develop new nutraceuticals and functional foods.     

Proximate Composition and Antioxidant Properties of Orange Mud Crab,Scylla olivacea

The proximate composition and antioxidant properties of the muscle tissues of Scylla olivacea are reported herein. The carbohydrate content was in the range of 1.52% to 3.07%, while protein varied from 13.30% to 17.28%. Meanwhile, the fat content for S. olivacea was found to be ranging from 0.20% to 0.57%. The moisture content in S. olivacea was 60.00%. Generally, no significant differences were observed in both male and female tissues of S. olivacea regarding its total phenolic content, 2,2-Diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) scavenging, and superoxide dismutase activities. However, significant differences were observed for the total flavonoid content and activity of catalase. The present results revealed the nutritional information and enzymatic and nonenzymatic antioxidant status of the tissues of S. olivacea.