Brown Macroalgae Sargassum cristaefolium Extract Inhibits Melanin Production and Cellular Oxygen Stress in B16F10 Melanoma Cells.

The brown macroalgae Sargassum has been reported for its anti-UV and photoprotective potential for industrial applications. This study evaluated the melanin inhibition activity of Sargassum cristaefolium (SCE) ethanol extract. Melanogenesis inhibition by SCE was assessed in vitro with B16-F10 melanoma cell models and in silico against melanin regulatory proteins Tyrosinase (TYR) and Melanocortin 1 Receptor (MC1R). The regulatory properties evaluated were the melanin content, intracellular tyrosinase activity and cellular antioxidant activities. In addition, the bioactive compounds detected in SCE were subjected to molecular docking against TYR and MC1R. Based on the results, 150 µg/mL SCE effectively inhibited the production of melanin content and intracellular tyrosinase activity. Cellular tyrosinase activity was reduced by SCE-treated cells in a concentration-dependent manner. The results were comparable to the standard tyrosinase inhibitor kojic acid. In addition, SCE effectively decreased the intracellular reactive oxygen species (ROS) levels in B16-F10 cells. The antioxidant properties may also contribute to the inhibition of melanogenesis. In addition, LCMS UHPLC-HR-ESI-MS profiling detected 33 major compounds. The results based on in silico study revealed that the bioactive compound putative kaurenoic acid showed a strong binding affinity against TYR (-6.5 kcal/mol) and MC1R (-8.6 kcal/mol). However, further molecular analyses are needed to confirm the mechanism of SCE on melanin inhibition. Nevertheless, SCE is proposed as an anti-melanogenic and antioxidant agent, which could be further developed into cosmetic skin care products.

Photoprotective effects of Sargassum thunbergii on ultraviolet B-induced mouse L929 fibroblasts and zebrafish.

BACKGROUND: Chronic exposure to ultraviolet B (UVB) causes a series of adverse skin reactions, such as erythema, sunburn, photoaging, and cancer, by altering signaling pathways related to inflammation, oxidative stress, and DNA damage. Marine algae have abundant amounts and varieties of bioactive compounds that possess antioxidant and anti-inflammatory properties. Thus, the objective of this study was to investigate the photoprotective effects of an ethanol extract of Sargassum thunbergii. METHODS: Sargassum thunbergii phenolic-rich extract (STPE) was prepared, and its activity against UVB damage was evaluated using L929 fibroblast cells and zebrafish. STPE was extracted and purified by 40% ethanol and macroporous resin XDA-7. Reactive oxygen species (ROS) and antioxidant markers, such as superoxide dismutase (SOD), catalase (CAT) activities, and malondialdehyde (MDA) content were analyzed. The effect of STPE on UVB-induced inflammation was determined by inflammatory cytokine gene and protein expression. The expression of signaling molecules in the Nuclear Factor KappaB (NF-κB) pathway was determined by western blotting. DNA condensation was analyzed and visualized by Hoechst 33342 staining. In vivo evaluation was performed by tail fin area and ROS measurement using the zebrafish model. RESULTS: The total polyphenol content of STPE was 72%. STPE reduced ROS content in L929 cells, improved SOD and CAT activities, and significantly reduced MDA content, thereby effectively alleviating UVB radiation-induced oxidative damage. STPE inhibited the mRNA and protein expression of TNF-α, IL-6, and IL-1α. STPE reversed DNA condensation at concentrations of 20 and 40 µg/mL compared with the UVB control. Moreover, STPE inhibited NF-κB signaling pathway activation and alleviated DNA agglutination in L929 cells after UVB irradiation. Additionally, 1.67 µg/mL STPE significantly increased the tail fin area in zebrafish, and 0.8-1.6 µg/mL STPE effectively eliminated excessive ROS after UVB radiation. CONCLUSIONS: STPE inhibited UVB-induced oxidative stress, inflammatory cytokine expression, and DNA condensation via the downregulation of the NF-κB signaling pathway, suggesting that it prevents UVB-induced photodamage, and has potential for clinical development for skin disease treatment.

Effects of Sargassum virgatum extracts on the testicular measurements, genomic DNA and antioxidant enzymes in irradiated rats.

BACKGROUND: Oxidative stress and reactive oxygen species (ROS) are primarily responsible for the development of male infertility after exposure to γ-irradiation. The present work aimed to assess the ameliorative and therapeutic roles of the aqueous and ethanolic extracts of the edible seaweed Sargassum virgatum (S. virgatum) on spermatogenesis and infertility in γ-irradiated Wistar rats. MATERIALS AND METHODS: Induction of infertility was performed by exposing the rats to 137Cs-gamma rays, using a single dose of 3.5 Gy. γ-irradiated rats were given the S. virgatum ethanolic (S. virgatum-EtOH) and aqueous extracts intraperitoneally on a daily base for two consecutive weeks at doses of 100 and 400 mg/kg body weight (b.wt.) for each seaweed extract. Morphometric data of the testes, semen quality indices, antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx), and deoxyribonucleic acid (DNA) fragmentation were assessed. The results obtained were taken during two-time intervals of 15 and 60 days from the commencement of the algal treatments. In vitro antioxidant assays and polyphenolic compounds of S. virgatum were characterized. RESULTS: Significant negative changes in the semen quality and morphometric data of the testes, as well as remarkable DNA fragmentation, were detected in the irradiated rats compared to the control. The levels of the endogenous antioxidant enzymes (SOD, CAT, GSH, and GPx) were also significantly diminished. Nonetheless, treatments of γ-irradiated rats with the S. virgatum-EtOH and aqueous extracts significantly improved the above-mentioned enzymes, in addition to noteworthy amendments in the dimensions of the testes, the semen quality, as well as the DNA structure. CONCLUSIONS: The ameliorative potency of S. virgatum to cure γ-irradiation-induced male infertility, particularly 400 mg/kg ethanolic extract for 60 days, is the result of the consistent therapeutic interventions of its potent antioxidant and anti-apoptotic polyphenols, particularly protocatechuic, p-hydroxybenzoic, rosmarinic, chlorogenic, cinnamic and gentisic acids, as well as the flavonoids catechin, hesperidin, rutin and quercetin. Besides its high-value nutraceutical importance, S. virgatum could be a natural candidate for developing well-accepted radioprotectant products capable of treating γ-irradiation-induced male infertility.

UVB protective effects of Sargassum horneri through the regulation of Nrf2 mediated antioxidant mechanism.

The present study aimed to evaluate the protective effect of a methanol extract of Sargassum horneri (SHM), which contains 6-hydroxy-4,4,7a-trimethyl-5,6,7,7a-tetrahydrobenzofuran-2(4H)-one (HTT) and apo-9'-fucoxanthinone, against ultraviolet B (UVB)-induced cellular damage in human keratinocytes and its underlying mechanism. SHM significantly improved cell viability of UVB-exposed human keratinocytes by reducing the generation of intracellular reactive oxygen species (ROS). Moreover, SHM inhibited UVB exposure-induced apoptosis by reducing the formation of apoptotic bodies and the populations of the sub-G1 hypodiploid cells and the early apoptotic cells by modulating the expression of the anti- and pro-apoptotic molecules, Bcl-2 and Bax, respectively. Furthermore, SHM inhibited NF-κB p65 activation by inducing the activation of Nrf2/HO-1 signaling. The cytoprotective and antiapoptotic activities of SHM are abolished by the inhibition of HO-1 signaling. In further study, SHM restored the skin dryness and skin barrier disruption in UVB-exposed human keratinocytes. Based to these results, our study suggests that SHM protects the cells against UVB-induced cellular damages through the Nrf2/HO-1/NF-κB p65 signaling pathway and may be potentially useful for the prevention of UVB-induced skin damage.

On the Health Benefits vs. Risks of Seaweeds and Their Constituents: The Curious Case of the Polymer Paradigm.

To exploit the nutraceutical and biomedical potential of selected seaweed-derived polymers in an economically viable way, it is necessary to analyze and understand their quality and yield fluctuations throughout the seasons. In this study, the seasonal polysaccharide yield and respective quality were evaluated in three selected seaweeds, namely the agarophyte Gracilaria gracilis, the carrageenophyte Calliblepharis jubata (both red seaweeds) and the alginophyte Sargassum muticum (brown seaweed). It was found that the agar synthesis of G. gracilis did not significantly differ with the seasons (27.04% seaweed dry weight (DW)). In contrast, the carrageenan content in C. jubata varied seasonally, being synthesized in higher concentrations during the summer (18.73% DW). Meanwhile, the alginate synthesis of S. muticum exhibited a higher concentration (36.88% DW) during the winter. Therefore, there is a need to assess the threshold at which seaweed-derived polymers may have positive effects or negative impacts on human nutrition. Furthermore, this study highlights the three polymers, along with their known thresholds, at which they can have positive and/or negative health impacts. Such knowledge is key to recognizing the paradigm governing their successful deployment and related beneficial applications in humans.

The Use of Invasive Algae Species as a Source of Secondary Metabolites and Biological Activities: Spain as Case-Study.

In the recent decades, algae have proven to be a source of different bioactive compounds with biological activities, which has increased the potential application of these organisms in food, cosmetic, pharmaceutical, animal feed, and other industrial sectors. On the other hand, there is a growing interest in developing effective strategies for control and/or eradication of invasive algae since they have a negative impact on marine ecosystems and in the economy of the affected zones. However, the application of control measures is usually time and resource-consuming and not profitable. Considering this context, the valorization of invasive algae species as a source of bioactive compounds for industrial applications could be a suitable strategy to reduce their population, obtaining both environmental and economic benefits. To carry out this practice, it is necessary to evaluate the chemical and the nutritional composition of the algae as well as the most efficient methods of extracting the compounds of interest. In the case of northwest Spain, five algae species are considered invasive: Asparagopsis armata, Codium fragile, Gracilaria vermiculophylla, Sargassum muticum, and Grateulopia turuturu. This review presents a brief description of their main bioactive compounds, biological activities, and extraction systems employed for their recovery. In addition, evidence of their beneficial properties and the possibility of use them as supplement in diets of aquaculture animals was collected to illustrate one of their possible applications.

The effect of Ulva lactuca and Sargassum hemiphyllum var. chinense on arsenic metabolites and enzymes in broilers.

This study investigated the effect of seaweed supplementation (Ulva lactuca (UL) or Sargassum hemiphyllum var. chinense (SHC)) on the distribution and metabolites of As in broiler breasts. Broilers fed 5% UL or 5% SHC ingested 1.4- or 78- fold greater total As than birds fed the control diet. The majority of As species were arsenate in the SHC feed and dimethylarsinic acid in breasts from chicks fed the SHC-containing diet. Arsenate and arsenobetaine were the dominant metabolites in the UL-containing feed, and arsenobetaine was the major metabolite in breasts from chicks fed the UL-containing diet. Feeding SHC enhanced hepatic S-adenosyl-methionine and arsenic methyltransferase, whereas feeding UL elevated renal arsenic methyltransferase. Taken together, considerable variation in the profiles of As species and As metabolites existed in broilers fed seaweed. The use of SHC-containing feeds in poultry production should be approached cautiously because of the potential accumulation of inorganic As species in chicken breasts.

New challenges for efficient usage of Sargassum fusiforme for ruminant production.

Sargassum fusiforme, which is a type of brown algae, can provide fiber and minerals to ruminant diets. In this study, dried S. fusiforme was tested in vitro at four different doses 1, 3, 5, and 10% of the total ration for its effect on ruminal fermentation characteristics, and gas profiles when incubated for 72 h. At a level of 1 and 10%, S. fusiforme supplementation augmented total volatile fatty acid (VFA) concentrations compared to that with 0% supplementation. In addition, total gas, methane, and carbon dioxide emissions significantly decreased at 3 and 24 h of incubation at this dose. An in situ trial was performed for 72 h with S. fusiforme to evaluate it as a potential feed ingredient by comparing its degradation parameters with timothy hay (Phleum pretense). 1H nuclear magnetic resonance spectroscopy profiling was used to identify and quantify metabolites of S. fusiforme. Mannitol, guanidoacetate and ethylene glycol were largely accumulated in S. fusiforme. Moreover, nutritious minerals for feed ingredients were present in S. fusiforme. Whereas a high concentration of arsenic was found in S. fusiforme, it was within the allowable limit for ruminants. Our results suggest that S. fusiforme could represent an alternative, renewable feed ingredient for ruminant diets, with nutritional, as well as environmental, benefits.

Modulation of drug resistance in Staphylococcus aureus by 132-hydroxy-(132-R/S)-pheophytin isolated from Sargassum polyceratium.

Efflux pumps are integral parts of the bacterial plasma membrane that are responsible for many cases of antibiotic resistance. Modulators of drug resistance are regarded as the most suitable new antibacterial therapies. We evaluated the extracts of Sargassum polyceratium and the isolated compound pheophytin (Sp-1) for antibiotic modifying activity in strains of Staphylococcus aureus with efflux pump. The minimum inhibitory concentrations (MICs) for norfloxacin, tetracycline and erythromycin were determined by the microdilution broth method, in the absence and presence of the extract at a sub-inhibitory concentration (MIC/4). The extracts and isolated compounds showed no significant antimicrobial activity, but they changed the antibiotic activity, decreasing bacterial resistance by 2 to 4x. Using a checkerboard method, it was also possible to observe the synergistic effect (ΣFIC ≤ 0.5) between Sp-1 and the antibiotics erythromycin and norfloxacin. The results indicate that the seaweed Sargassum polyceratium and pheophytin are potential sources of an antibiotic adjuvant that modulates bacterial resistance, acting as a putative efflux pump inhibitor.

Chemical diversity and anti-proliferative activity of marine algae.

The chemical diversity of three macroalgae (Ulva reticulata, Sargassum wightii, Gracilaria sp) were determined using the GC-MS method with principal component analysis (PCA) and their potential efficacy against human pathogens and cervical carcinoma cells evaluated using MTT bioassay method. Our results showed that >30 metabolites were detected in three seaweeds, among these, steroids and fatty acids are the most dominant chemical group that highly contributes to discriminate this species. The PCA of GC-MS mass spectral variables showed a clear discrimination between three different species based on the phytochemical diversity of seaweeds. The extracts of U. reticulata exhibited anti-microbial activity with Pseudomonas aeruginosa (6.00 mm) and showed potential anti-proliferative activity against the HeLa cells (IC50 37 µmol/L) at concentration 1-50 µM treatment. Results of this study concluded that PCA analysis of mass spectral variables could be utilized as a reliable tool for species discrimination and chemotaxonomic classification of seaweeds.

An Insight into Sargassum muticum Cytoprotective Mechanisms against Oxidative Stress on a Human Cell In Vitro Model.

Sargassum muticum is a brown seaweed with strong potential to be used as a functional food ingredient, mainly due to its antioxidant properties. It is widely used in traditional oriental medicine for the treatment of numerous diseases. Nevertheless, few studies have been conducted to add scientific evidence on its effects as well as on the mechanisms of action involved. In this work, the human cell line MCF-7 was used as an in vitro cellular model to evaluate the capability of Sargassum muticum enriched fractions to protect cells on an oxidative stress condition. The concentration of the bioactive compounds was obtained by vacuum liquid chromatography applied on methanol (M) and 1:1 methanol:dichloromethane (MD) crude extracts, resulting in seven enriched fractions from the M extraction (MF2-MF8), and eight fractions from the MD extraction (MDF1-MDF8). All fractions were tested for cytotoxic properties on MCF-7 cells and the nontoxic ones were tested for their capacity to blunt the damaging effects of hydrogen peroxide-induced oxidative stress. The nontoxic effects were also confirmed in 3T3 fibroblast cells as a nontumor cell line. The antioxidant potential of each fraction, as well as changes in the cell's real-time hydrogen peroxide production, in the mitochondrial membrane potential, and in Caspase-9 activity were evaluated. The results suggest that the protective effects evidenced by S. muticum can be related with the inhibition of hydrogen peroxide production and the inhibition of Caspase-9 activity.

Isolation of a novel alginate lyase-producing Bacillus litoralis strain and its potential to ferment Sargassum horneri for biofertilizer.

Algae have long been used to augment plant productivity through their beneficial effects. Alginate oligosaccharide is believed to be one of the important components to enhance growth and crop yield. In this study, we isolated and characterized a Bacillus litoralis strain, named Bacillus M3, from decayed kelps. We further demonstrated that the M3 strain could secrete alginate lyase to degrade alginate. The crude enzyme exhibited the highest activity (33.74 U/mg) at pH 7.0 and 50°C. The M3 strain was also able to ferment the brown alga Sargassum horneri. Fermentation results revealed that a fermentation period of 8-12 hr was the best harvest time with the highest level of alginate oligosaccharides. Plant growth assay showed that the seaweed fermentation extract had an obvious promotion effect on root and seedling growth of Lycopersicon eseulentum L. Our results suggest that fermentation extract of Sargassum horneri by the novel strain of Bacillus litoralis M3 has significant development potential for biofertilizer production and agriculture application.

Comparative Studies on the Characteristic Fatty Acid Profiles of Four Different Chinese Medicinal Sargassum Seaweeds by GC-MS and Chemometrics.

Sargassum seaweeds produce abundant biomass in China and have long been used as herbal medicine and food. Their characteristic fatty acid (FA) profiles and related potential function in promoting cardiovascular health (CVH) have not been systematically investigated. In this study, FA profiles of four medicinal Sargassum were characterized using GC-MS. Principal component analysis was used to discriminate the four medicinal Sargassum, and orthogonal projection to latent structures discriminant analysis was carried out between the two official species HAI ZAO and between the two folk medicine species HAI QIAN. In all of the algae investigated, the major SFA and MUFA were palmitic and stearic acid, respectively, while the major PUFAs were linoleic, arachidonic, and eicosapentaenoic acid. S. fusiforme and S. horneri had higher concentrations of PUFAs. With respect to CVH, all of the studied species, particularly S. fusiforme, exhibited satisfactory levels such as PUFA/SFA ratio and n-6/n-3 ratio. Each species possesses a unique FA profile and is discriminated clearly. Potential key FA markers (between the two Chinese official species, and between the two folk species) are assessed. The study provides characteristic fatty acid profiles of four Chinese medicinal Sargassum and their related potential function in promoting CVH.