Antioxidant Potential and Phenolic Compounds of Brown Seaweeds Turbinaria conoides and Turbinaria ornata (Class: Phaeophyceae)

ABSTRACT

Antioxidant potential, total phenolic content, and high performance liquid chromatography-based solvent extract fingerprints of phenolic constituents of brown seaweeds, Turbinaria conoides and Turbinaria ornata, were evaluated. The ethyl acetate (EtOAc) fraction of the seaweeds registered greater phenolic content and antioxidant activities. Salicylic acid, gallic acid, quercetin, and syringic acid were predominant in the EtOAc fraction of T. conoides, while the main components in EtOAc fraction of T. ornata were quercetin and salicylic acid. This study demonstrated the candidacy of Turbinaria spp. as a potential source of antioxidant phenolics for use as food supplements and nutraceuticals to deter deleterious free radical-induced disorders and diseases.     

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.     

4种海藻膳食纤维清除自由基的比较研究

采用羟基自由基体系、超氧阴离子自由基体系、烷基自由基引发的亚油酸氧化体系和DPPH体系对江蓠(Gracilaria)、麒麟菜(Eucheuma)、马尾藻(Sargassum)、海带(Laminaria)4种膳食纤维清除自由基的活性进行研究。结果表明，在羟基自由基体系中，江蓠、麒麟菜、马尾藻、海带4种膳食纤维的IC50分别为5．2mg／mL、5．5mg／mL、4．4mg／mL和4．1mg/mL；在超氧阴离子自由基体系中，江蓠、麒麟菜膳食纤维的IC50分别为4．8mg/mL和5．3mg/mL，而马尾藻、海带膳食纤维的最高清除率分别为36％和42％；在烷基自由基引发的亚油酸氧化体系中，江蓠、麒麟菜膳食纤维的最高清除率分别为36％和26％，马尾藻、海带膳食纤维的IC50分别为4．1mg/mL和3．5mg/mL；在DlPIH体系中，江蓠、麒麟菜、马尾藻膳食纤维的最高清除率分别为31％、11％和26％，海带膳食纤维的IC50为6．2mg/mL。在各体系中，与相应的专一性阳性参照物对比，证明这4种海藻膳食纤维对自由基有一定的清除作用。     

Functional Properties of the Marine Gastropod Molluscs Chicoreus ramosus and Babylonia spirata Collected from the Southern Coast of India

ABSTRACT

This study characterized the functional properties of ethyl acetate-methanol (EA-MeOH) and chloroform extracts of the muricid gastropod Chicoreus ramosus and buccinid Babylonia spirata. The EA-MeOH extract of B. spirata was a potent quencher of radical cation (IC₉₀ < 1 mg/mL), whereas that of C. ramosus held greater anti–inflammatory potential (IC₉₀ 5-lipoxygenase inhibition 1.74 mg/mL) than the buccinid gastropod. The EA-MeOH extract of C. ramosus displayed potent antidiabetic activities as deduced by its attenuation properties against carbolytic enzymes α-amylase and α-glycosidase (IC₉₀ 1.06 and 2.25 mg/mL, respectively) than those exhibited by B. spirata (IC₉₀ 2.32 and 4.50 mg/mL, respectively). The spectroscopic dereplication studies to determine probable chemical groups in the solvent extracts of the studied gastropods revealed the presence of functionalities, which might augment the electronic properties of the bioactive principles present within the extract, thereby enhancing their activity. Thus, the present study recognized that marine gastropods C. ramosus and B. spirata have potential functional implications against oxidative stress-induced diseases, such as diabetes and inflammation. This research supports further investigation of these previously uncharacterized marine gastropod species to isolate potential bioactive leads for use against various biological targets and to develop functional food formulations.     

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.     

Optimized Extraction,Preliminary Characterization and Evaluation of the in Vitro Anticancer Activity of Phlorotannin-Rich Fraction from the Brown Seaweed,Cystoseira sedoides

Brown seaweeds produce useful bioactive substances with high cosmetic and pharmacological values due to the presence of antioxidant derivatives, mainly phlorotannins (PHT), which are of particular interest. A central composite rotatable design (CCRD) with three variables (extraction time, dry material-to-solvent ratio and ethanol concentration) and two responses was performed to optimize the microwave-assisted extraction (MAE) of phlorotannins from Cystoseira sedoides using response surface methodology (RSM). Results showed that the independent variables significantly affected both phlorotannin content and the scavenging capacity. The optimum operating conditions were extraction time, 101.74 sec; dry material-to-solvent ratio, 1:10 g/mL; and ethanol extraction, 50%. Under these conditions, the predicted values of PHT content and radical scavenging activity-IC50 were close to the observed values and were 383.887 µg PGE/g Dm and 18.353 µg/mL, respectively. Characterization of the phlorotannin-rich fraction was conducted by high-performance liquid chromatography and Fourier transform infrared spectroscopy. The evaluation of the anticancer activity against MCF-7 breast cancer cell line showed a potent activity to trigger apoptotic death in more than a half of the MCF-7 cells, with an estimated IC50 value of 78 μg/mL. In addition, this fraction induced a notable growth regression effect on 3D spheroids model in a concentration-dependent manner, with a growth rate of about 1.17, at 200 µg/mL.

Abbreviations: CCRD: Central composite rotatable design; Dm: Dry material; DMBA: 2,4-dimethoxy benzaldehyde; DMSO: Dimethyl sulfoxide; DPPH: 1,1-diphenyl-2-picrylhydrazyl; EDTA: Ethylene diamine tetraacetic acid; FBS: Fetal bovine serum; FT-IR: Fourier transform infrared; HPLC: High-performance liquid chromatography; IC₅₀: Half-maximal inhibitory concentration; MAE: Microwave-assisted extraction; Min: minutes; PBS: Phosphate buffered saline; PGE: Phloroglucinol equivalent; PHT: Phlorotannins; PHT-SED: phlorotannins derived from Cystoseira sedoides; PI: Propidium iodide; RSA: Radical scavenging activity; RSM: Response surface methodology; Sec: seconds     

胰蛋白酶酶解制备孔鳐软骨蛋白寡肽及其抗氧化活性

以孔鳐软骨为材料,采用盐酸胍抽提、丙酮分级沉淀,制备孔鳐软骨蛋白;以DPPH·和HO·清除活性为导向,采用胰蛋白酶酶解、膜超滤、DEAE-52阴离子交换层析、Sephadex G-15凝胶层析和反相高效液相色谱(RP-HPLC)等技术,制备抗氧化肽,并对其活性进行系统评价。结果显示,孔鳐软骨蛋白经胰蛋白酶酶解和分离纯化得到2个抗氧化肽RCPE-A和RCPE-B,经氨基酸序列分析确定其序列分别为Gly-Glu-Glu-Gly-Pro-Arg-Gly (GEEGPRG)和Gly-Glu-Glu-Gly-Thr-Met-Gly-Leu (GEEGTMGL),质谱(ESI-MS)测定其分子量分别为700.71和792.87 u。体外自由基清除实验结果显示,RCPE-A与RCPE-B对DPPH·(EC₅₀ 2.94和1.16 mg/mL)、HO·(EC₅₀ 0.34和0.54 mg/mL)、ABTS⁺·(EC₅₀ 0.34和0.10 mg/mL)和O₂^-·(EC₅₀ 0.11和0.03 mg/mL)具有良好的清除作用,RCPE-A与RCPE-B亦显示出较强的脂质过氧化抑制作用。研究表明,孔鳐软骨蛋白酶解物及制备多肽可用于抗氧化相关的功能食品开发,也可以用作抗氧化剂延长相关产品的货架期。     

A Comparative Study on Some Functional and Antioxidant Properties of Kilka Meat,Fishmeal, and Stickwater Protein Hydrolysates

This study determined some antioxidative activities and functional properties of hydrolyzed proteins prepared from kilka (Clupeonella sp.) meat (KMH), kilka fishmeal (KFH), and stickwater (SWH). The highest degree of hydrolysis (DH) was 25.02% (p < 0.05) in SWH; however, the difference in DH between KMH and KFH was not significant. KFH had the highest protein content (85.69%) compared with other hydrolysis samples. The Fourier transform infrared spectra of KFH had the highest amide absorption picks (p < 0.05). Solubility at neutral pH was 84.09%, 86.00%, and 93.08% for KMH, KFH, and SWH, respectively. The highest fat absorption capacity was obtained with KFH (204 mg/50 mg). KFH also showed the best foaming properties with 25.66% foaming capacity and proper stability during 60 min (p < 0.05). The highest and lowest whiteness values were obtained in KMH (72.33%) and SWH (36.54%), respectively (p < 0.05). The highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC₅₀ value of 1.99 mg/mL) and 2,2?-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (IC₅₀ value of 2.00 mg/mL) radical scavenging activities were measured at the highest concentrations (40 mg/mL) in KFH (p < 0.05). KFH had the best functional and antioxidant properties, while SWH had a strong ability to inhibit lipid oxidation. Therefore, stickwater from fishmeal production factories is a potential resource for use in developing value-added products instead of being discarded.     

Carotenoid Profile of Edible Japanese Seaweeds: An Improved HPLC Method for Separation of Major Carotenoids

An improved multi-step gradient reverse phase high performance liquid chromatography (HPLC) method to simultaneously separate major carotenoids from natural as well as food samples was developed. Quantitative profiling of carotenoid compounds was carried out on three edible brown seaweeds (Sargassum horneri, Cystoseira hakodatensis, and Undaria pinnatifida) and three red seaweeds (Gracilaria vermiculophylla, Grateloupia asiatica, and Grateloupia livida). Fucoxanthin (Fx) was detected in all the brown seaweeds with quantities (mg g^?1 dry weight [dwt]) ranging from 1.3 ± 0.3 in C. hakodatensis to 2.4 ± 0.1 in S. horneri. U. pinnatifida, commonly known as wakame, had a Fx content of 2.3 ± 0.1 mg g^?1 dwt. In the case of red seaweeds, zeaxanthin (Zx) was the major carotenoid, and G. vermiculophylla had the highest Zx content (80.2 μg g^?1 dwt) among the red seaweeds apart from small amounts of Fx (9.1 μg g^?1 dwt). Similarly, the other two species of red seaweeds, G. asiatica and G. livida, contained (μg g^?1 dwt) lutein (Lut), Fx, and Zx as the major carotenoids (G. asiatica: Lut 10.4, Fx 1.5, Zx 1.1; G. livida: Lut 9.3, Fx 3.5, Zx 1.0). The results suggest the usefulness of edible varieties (barring wakame) of seaweeds as dietary sources of carotenoids.     

Utilization of Shrimp By-Products by Bioconversion with Medical Fungi for Angiotensin I-Converting Enzyme Inhibitor and Antioxidant

ABSTRACT

A liquid fermentation process to bioconvert shrimp by-products was developed with two species of fungi, Boletus edulis and Suillus bovinus. Angiotensin I-converting enzyme (ACE) inhibitory, antioxidant activities of bioconverted products and the deodorization effect of fungal bioconversion were determined. Two species of fungi could grow quickly in shrimp by-products medium and deodorize shrimp by-products. Bioconverted products had higher ACE inhibitory and antioxidant activities than control medium. Water extracts without crude polysaccharides from mycelia of B. edulis had the highest ACE inhibitory activity (IC₅₀ = 0.084 ± 0.011 mg/mL). Crude exopolysaccharides of B. edulis had higher antioxidant activity. Bioconversion with the fungus was proven to be a novel, practicable way to recycle shrimp by-products.     

Functional Properties of Ethyl Acetate-methanol Extract of Commonly Edible Molluscs

ABSTRACT

Marine molluscs are consumed as culinary delicacies and represent a relatively untapped source of natural functional food ingredients. The bioactive potential of ethyl acetate-methanol (C₂H₅OAc/CH₃OH) extract of molluscs Uroteuthis duvaucelii, Amphioctopus marginatus, Crassostrea madrasensis, and Sepiella inermis were demonstrated using different in vitro systems. The C₂H₅OAc/CH₃OH extract of A. marginatus displayed greater 2, 2-diphenyl-1-picryl-hydrazil (IC₉₀ 1.76 mg mL^?1) radical quenching capacity along with potential hydroxymethylglutaryl coenzyme-A reductase (HMGCR)-inhibiting activity (IC₉₀ 1.21 mg mL^?1) and angiotensin converting enzyme-I inhibitory property (ACE-I) (IC₉₀ 0.87 mg mL^?1) compared to those displayed by other molluscs. The organic extract of S. inermis set forth significantly higher pro-inflammatory 5-lipoxygenase inhibitory property (IC₉₀ 1.96 mg mL^?1) along with potential antidiabetic activity as determined by dipeptidyl peptidase-4 (DPP-4) antagonistic activities (IC₉₀ 2.62 mg mL^?1, P < .05). Significant correlations were observed between bioactive properties and electronegative groups of organic extracts of a mollusc. The free radical quenching property of the extracts exhibited a positive correlation towards other bioactivities, implicating the role of antioxidant property of the compounds in the extract to inhibit lifestyle ailments. The present study indicated that S. inermis and A. marginatus could be utilized as functional food ingredients to combat hypertension, hyperlipidemia, and inflammation-related risks.     

Protein Hydrolysates and Ultrafiltration Fractions Obtained from Krill (Euphausia superba): Nutritional,Functional, Antioxidant,and ACE-Inhibitory Characterization

ABSTRACT

Krill (Euphausia superba) was hydrolyzed by proteolytic enzymes in order to produce multifunctional bioactive peptides, and their functional properties were evaluated. Krill protein hydrolysate (KPH) by pepsin with 4-h hydrolysis showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and angiotensin I converting enzyme (ACE) inhibitory activities. The solubility and foaming properties of KPH were higher than those of the unhydrolyzed krill protein at a wide range of pHs. KPH was further fractionated based on molecular weight. The 1- to 3-kDa peptide fraction exhibited the highest DPPH scavenging activity (IC₅₀ value of 0.5 mg/mL), oxygen radical absorbance capacity (497.39 ± 4.31 µM TE/mg fraction), 2,2-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid cation radical scavenging activity (48.41 ± 0.23 µM TE/mg fraction), and reducing power (110.40 ± 2.07 µM TE/mg fraction). However, the < 1-kDa peptide fraction exhibited a higher ACE inhibitory activity than that of other fractions. The 1- to 3- and < 1-kDa peptide fractions are rich in aromatic and hydrophobic amino acids, respectively.     

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。     

Antioxidant Potential of Water Hyacinth (Eichornia crassipes): In Vitro Antioxidant Activity and Phenolic Composition

The aims of the present study were (a) to extract and quantify the main phenolic acids and tocopherols from the petiole, leaves, and flowers of Eichornia crassipes; (b) to evaluate the antioxidant capacity of the extracts in four in vitro systems (1,1-diphenyl-2-pycryl-hydrazyl [DPPH] radical scavenging ability, iron chelating activity, reducing power, and prevention of oxidation in a liposome model system); and (c) its effectiveness in retarding lipid peroxidation in fish oil by accelerated stability test. Significant differences were observed in total and individual phenolic contents and in the antioxidant activities of extracts from the various parts of E. crassipes. Out of the 11 phenolic acids analyzed, ethanolic extracts contained high amounts of gallic, protocatechuic, gentisic, and p-hydroxybenzoic acid, whereas, water extracts contained less amounts of a varied number of phenolic acids. Ethanolic extracts of flower, which contained the highest total phenolic content, were found to have high DPPH radical scavenging activity and reducing power. However, ethanolic extracts of leaf exerted a high Fe²⁺ chelating activity and also inhibited lipid peroxidation process both in liposomes and fish oil. Our results demonstrate that E. crassipes, an underutilized aquatic weed, could be a potential natural antioxidant source for food, feed, and pharmaceutical applications.     

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。     

Preparation of Cookies with Various Native Seaweeds Found on the Korean Coast

ABSTRACT

We investigated the quality characteristics of cookies prepared using different seaweeds native to the Korean coast. Flour made from four different seaweed species (Sargassum fulvellum, Enteromorpha linza, Codium fragile, and Hizikia fusiforme) was used to replace 5% of the regular flour while preparing the cookies. The seaweeds significantly affected solvent retention capacity, thus interfering with gluten network formation. Consequently, the addition of seaweed changed several variables in the cookies, such as moisture content, spread factor, and breaking stress. In sensory evaluation, cookies with Hizikia fusiforme were the most preferred, confirming the possibility of developing cookie products using this seaweed species.     

Optimization of Antioxidant Activity and Phenolic Compound Extraction Conditions from Red Seaweed (Laurencia obtuse)

ABSTRACT

Response surface methodology was used to investigate the effect of ultrasound-assisted extraction conditions including solvent:seaweed ratio (10:1–30:1), extraction temperature (30–50°C), and extraction time (30–60 min) on the total phenolic compounds and antioxidant activity of red seaweed (Laurencia obtuse) extracts. The optimum extraction parameters for maximum phenolic content were as follows: solvent:seaweed ratio, 30:1; extraction temperature, 50°C; and extraction time, 42.8 min. The experiment results showed that the solvent:seaweed ratio was the most significant parameter for the extraction. The optimum extraction conditions for maximum antioxidant activity were as follows: solvent:seaweed ratio, 24.3:1; extraction temperature, 45.3°C; and extraction time, 58 min. Under the above-mentioned conditions, the experimental total phenolic content and antioxidant activity value were 26.23 ± 0.75 mg GAE/g seaweed and 120.89 ± 0.81 TEAC, respectively, of seaweed tested, which are well compatible with the predicted contents.     

Effect of hot water extracts of brown seaweeds Sargassum spp. on growth and resistance to white spot syndrome virus in shrimp Penaeus monodon postlarvae

An experiment was conducted to evaluate the effect of a hot water extract of brown seaweeds Sargassum duplicatum and Sargassum wightii on the growth and white spot syndrome virus (WSSV) resistance in shrimp Penaeus monodon postlarvae (PL). Artemia nauplii (instar II) were enriched with both seaweed extracts at various concentrations (250, 500 and 750 mg L^?1) and fed to the respective P. monodon (PL15–35) group for 20 days. A control group was also maintained without seaweed extract supplementation. The weight gain of the experimental groups was significantly higher (0.274–0.323 g) than the control group (0.261 g). Similarly, the specific growth rate was also significantly higher (16.27–17.06%) in the experimental groups than in the control group (16.03%). After 20 days of the feeding experiment, the shrimp PL were challenged with WSSV for 21 days. During the challenge test, the control shrimp displayed 100% mortality within 8 days. In contrast, the mortality percentage of the highest concentration (750 mg L^?1) of seaweed extract enriched Artemia nauplii fed shrimp was 54–79%. Comparatively, low mortality was observed in S. wightii extract‐enriched Artemia nauplii fed shrimp. The polymerase chain reaction analysis indicated the concentration‐dependent infection of WSSV in P. monodon PL.     

Identification of Polyphenols from Chilean Brown Seaweeds Extracts by LC-DAD-ESI-MS/MS

Polyphenol profiles were characterized in extracts of three Chilean brown seaweeds, Durvillaea antarctica (Chamisso) Hariot, Lessonia spicata (Suhr) Santelices, and Macrocystis integrifolia (Bory) by liquid chromatography with mass spectrometry detection (LC-MS/MS). Phlorotannins with different degrees of polymerization were identified in D. antarctica (trimers to octamers) and L. spicata (trimers to tetramers). No signals related to phlorotannins compounds were detected in M. integrifolia. L. spicata and M. integrifolia showed a great variety of flavonoid compounds in comparison with D. antarctica, mainly identified as glycoside forms in all the extracts. The antioxidant activity of brown seaweed extracts measured by ferric reducing power (FRAP) and oxygen radical absorbance capacity (ORAC) was significantly higher in D. antarctica, followed by M. integrifolia and L. spicata, in line with the total phenolic (TP) content. However, D. antarctica and M. integrifolia showed similar activity for free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) in spite of the differences found in TP content. D. antarctica as well as L. spicata would represent a potential source of phlorotannins, whereas M. integrifolia could be considered as an alternative source of flavonoids. The identification of polyphenols in extracts of Chilean brown seaweeds opens innovative opportunities for their use in the food and pharmaceutical industries.     

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.