Phenolic compounds and antioxidant capacity of Pediastrum boryanum (Chlorococcales) biomass.

Bioactive compounds, synthesized by photosynthetic microorganisms, have drawn the attention of the pharmaceutical field. This study aimed at evaluating synthesis and in vitro antioxidant capacity of phenolic compounds produced by a microalgae species P. boryanum, which was grown in six different culture media (standard BG11, modified BG11/MBG11, standard WC, modified WC, WC*2 and basal). The highest concentrations of biomass (1.75 ± 0.01 g.L-1) and phenolic content (3.18 ± 0.00 mg.g-1) were obtained when P. boryanum was grown in MBG11 and phenolic acids were identified: gallic, protocatechuic, chlorogenic, hydroxybenzoic and vanillic ones. All extracts exhibited scavenger activity in the ABTS assay and inhibited peroxidase. However, phenolic compounds from P. boryanum grown in BG11 and MBG11 had the most potent scavenger activity in the DPPH assay. In sum, P. boryanum can be a new source of free phenolic compounds with potential antioxidant activity when grown in MBG11, since it yields high amounts of biomass and phenolic compounds.

Comparison of Different Methods for Extracting the Astaxanthin from Haematococcus pluvialis: Chemical Composition and Biological Activity.

In this study, the impact of different cell disruption techniques (high-pressure micro fluidization (HPMF), ionic liquids (ILs), multi-enzyme (ME), and hydrochloric acid (HCl)) on the chemical composition and biological activity of astaxanthin (AST) obtained from Haematococcus pluvialis was investigated. Results indicated that all cell disruption techniques had a significant effect on AST composition, which were confirmed by TLC and UPC2 analysis. AST recovery from HCl (HCl-AST) and ILs (ILs-AST) cell disruption techniques was dominant by free and monoesters AST, while AST recovery from HPMF (HPMF-AST) and ME (ME-AST) cell disruption techniques was composed of monoesters, diesters, and free AST. Further biological activity analysis displayed that HCl-AST showed the highest ABTS and DPPH activity, while ILs-AST showed better results against the ORAC assay. Additionally, ILs-AST exhibits a stronger anti-proliferation of HepG2 cells in a dose-dependent manner, which was ascribed to AST-induced ROS in to inhibit the proliferative of cancer cells.

Characterization of Astaxanthin Nanoemulsions Produced by Intense Fluid Shear through a Self-Throttling Nanometer Range Annular Orifice Valve-Based High-Pressure Homogenizer.

Stable, oil-in-water nanoemulsions containing astaxanthin (AsX) were produced by intense fluid shear forces resulting from pumping a coarse reagent emulsion through a self-throttling annular gap valve at 300 MPa. Compared to crude emulsions prepared by conventional homogenization, a size reduction of over two orders of magnitude was observed for AsX-encapsulated oil droplets following just one pass through the annular valve. In krill oil formulations, the mean hydrodynamic diameter of lipid particles was reduced to 60 nm after only two passes through the valve and reached a minimal size of 24 nm after eight passes. Repeated processing of samples through the valve progressively decreased lipid particle size, with an inflection in the rate of particle size reduction generally observed after 2-4 passes. Krill- and argan oil-based nanoemulsions were produced using an Ultra Shear Technology™ (UST™) approach and characterized in terms of their small particle size, low polydispersity, and stability.

Microalgal extract from thermotolerant Coelastrella sp. F50 retards the liver tumor progression by targeting hepatic cancer stem cells.

Microalgae extracts have shown antitumor activities. However, the antitumor mechanism of them is not yet completely clear, especially the effect on cancer stem cells (CSCs). This study aimed to elucidate the antitumor activity and mechanism of microalgal extract from thermotolerant Coelastrella sp. F50 (F50) in hepatocellular carcinoma (HCC). Oncogenic behaviors were analyzed using cell proliferation, colony formation, invasion, sphere formation, and side population cells (SPCs) assays in HCC cells after F50 treatment. The molecular mechanism was further studied by quantitative real-time PCR, immunoblot, and immunofluorescence analyses. The chemopreventive efficacy of F50 was evaluated in rat orthotopic hepatoma, and the hepatic pathologies were investigated by immunohistochemical, immunoblot, and immunofluorescence analyses. F50 specifically suppressed hepatic CSCs (tumor spheres, drug efflux, CD133/ABCG2 CSCs markers) with no cytotoxicity in vitro. In the animal experiments, prophylactic F50 administration significantly attenuated tumor progression and improved liver function in HCC-bearing rats. In the mechanistic analysis, F50 potentially inhibited cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2 ) axis in HCC cells and rat hepatoma, and exogenous PGE2 restored CSCs properties in F50-treated HCC cells. In summary, F50 extract inhibits hepatic CSCs by COX-2/PGE2 downregulation and may facilitate a novel phytotherapy for HCC prevention.

Haematococcus pluvialis Carotenoids Enrich Fractions Ameliorate Liver Fibrosis Induced by Thioacetamide in Rats: Modulation of Metalloproteinase and Its Inhibitor.

Hepatic fibrosis is a consequence of chronic liver diseases. Metalloproteinase and its inhibitor have crucial roles in the resolution of liver fibrosis. The current relevant study is aimed to evaluate the therapeutic effect of Haematococcus pluvialis (H. pluvialis) extract, astaxanthin-rich fraction, astaxanthin ester-rich fraction, and ß-carotene-rich fraction as well as their mechanisms of action in curing hepatic fibrosis induced by thioacetamide (TAA). Liver fibrosis was induced using TAA (intraperitoneal injection, two times a week for 6 weeks), in a rat model and H. pluvialis extract (200 mg/kg), and other fractions (30 mg/kg) were orally administered daily for 4 weeks after the last TAA injection. Based on HPLC analysis, H. pluvialis extract contains ß-carotene (12.95 mg/g, extract) and free astaxanthin (10.85 mg/g, extract), while HPLC/ESI-MS analysis revealed that H. pluvialis extract contains 28 carotenoid compounds including three isomers of free astaxanthin, α or ß-carotene, lutein, 14 astaxanthin mono-esters, 5 astaxanthin di-esters, and other carotenoids. H. pluvialis and its fractions reduced liver enzymes, nitric oxide, collagen 1, alpha-smooth muscle actin, and transforming growth factor-beta as well as elevated catalase antioxidant activity compared to the TAA group. Also, H. pluvialis extract and its fractions exceedingly controlled the balance between metalloproteinase and its inhibitor, activated Kupffer cells proliferation, and suppressed liver apoptosis, necrobiosis, and fibrosis. These findings conclude that H. pluvialis extract and its fractions have an antifibrotic effect against TAA-induced liver fibrosis by regulating the oxidative stress and proinflammatory mediators, suppressing multiple profibrogenic factors, and modulating the metalloproteinase and its inhibitor pathway, recommending H. pluvialis extract and its fractions for the development of new effective medicine for treating hepatic fibrosis disorders.

Cholinesterase inhibitory activity, antioxidant properties, and phytochemical composition of Chlorococcum sp. extracts.

In this study, Chlorococcum sp. was investigated for its cholinesterase inhibitory potentials and antioxidant activity. The algal sample was cultivated, harvested, and extracted sequentially using n-hexane, dichloromethane, and ethanol. The extracts were characterized using Fourier transmission infra-red (FTIR) and Gas Chromatography-Mass Spectrometry. The metal chelating, radical scavenging activities, as well as anticholinesterase potentials of the algal extract, was also investigated. FTIR characterization of the microalgal biomass revealed the presence of phenolic compounds, alkaloids, polysaccharides, and fatty acids. The extracts showed the presence of phytol, neophytadiene, butylated hydroxyl toluene, and 3-tert-butyl-4-hydroxyanisole. The ethanol extract showed the highest DPPH (IC50  = 147.40 µg/ml) and OH (IC50  = 493.90 µg/ml) radical scavenging and metal chelating (IC50  = 83.25 µg/ml) activities. Similarly, the ethanol extract (IC50  = 13.83 µg/ml) exhibited the highest acetylcholinesterase inhibitory activity, while the dichloromethane extract showed the highest butyrylcholinesterase inhibitory activity. All the extracts exhibited antioxidant properties and inhibitory effects against butyrylcholinesterase and acetylcholinesterase; however, ethanol extracts showed better activity. PRACTICAL APPLICATIONS: Biomass obtained from some microalgal species is commonly used as dietary supplements and nutraceuticals due to the presence of high-valued products. However, the antioxidant and anticholinesterase activities of biomass from Chlorococcum sp. have not been explored. Chlorococcum sp. extracts contain some antioxidants such as 3-tert-Butyl-4-hydroxyanisole, butylated hydroxytoluene, phytol, and neophytadiene. Characterization of the extracts also revealed the presence of phenolic compounds, polysaccharides, and fatty acids. These compounds may contribute to the observed antioxidant and anticholinesterase activities of Chlorococcum sp. The result of this study suggests that Chlorococcum sp. may contain some nutraceuticals which could be used as antioxidants and cholinesterase inhibitors.

Effects of dietary supplementation of natural astaxanthin from Haematococcus pluvialis on antioxidant capacity, lipid metabolism, and accumulation in the egg yolk of laying hens.

The present study evaluated the effects of natural astaxanthin (ASTA) from Haematococcus pluvialis on the antioxidant capacity, lipid metabolism, and ASTA accumulation in the egg yolk of laying hens. Hy-Line Brown layers (n = 288, 50 wk old) were randomly assigned to 1 of 4 dietary treatment groups. Each group had 6 replicates of 12 hens each. All birds were given a corn-soybean meal-based diet containing 0, 25, 50, or 100 mg/kg ASTA for 6 wk. The results showed that the total antioxidant capacity, superoxide dismutase level, and glutathione peroxidase level in the plasma, livers, and egg yolks were significantly increased in the ASTA groups compared with those of the control group (P < 0.05), whereas the content of malondialdehyde linearly decreased (P < 0.05). The plasma levels of high-density and very-low-density lipoprotein cholesterol in the ASTA groups were significantly higher than those in the control group (P < 0.05). In addition, ASTA supplementation decreased low-density lipoprotein cholesterol and triglyceride plasma levels (P < 0.05). However, there were no significant differences in the other lipid metabolism parameters among the ASTA-supplemented groups relative to the control group except for an increase in high-density lipoprotein cholesterol in the liver. Compared with the control, dietary ASTA supplementation significantly increased the enrichment of ASTA in egg yolks at the end of week 2, 4, and 6 (P < 0.05). The mRNA expression of scavenger receptor class B type 1 (SCARB1) and very-low-density lipoprotein receptor (VLDLR) in the ASTA groups was markedly higher (P < 0.05) than that in the control group in the liver and ovaries, respectively. In conclusion, these results suggest that dietary ASTA enhances the antioxidant capacity and regulates lipid metabolism in laying hens. ASTA enrichment in egg yolks may be closely related to the upregulation of SCARB1 and VLDLR gene expression.

Effects of supplementing natural astaxanthin from Haematococcus pluvialis to laying hens on egg quality during storage at 4°C and 25°C.

The objective of this study was to evaluate the effects of different levels of dietary natural astaxanthin (ASTA) (from the microalga Haematococcus pluvialis) and storage at 4°C and 25°C on the quality of eggs from laying hens. Nongda No. 3 laying hens (n = 450) were randomly allocated to 1 of 5 dietary treatments. Each treatment had 6 replicates of 15 hens each. All birds were assigned to a corn-soybean meal-based diet containing 0, 20, 40, 80, or 160 mg/kg natural ASTA for 4 wk. A total of 540 eggs were collected at the end of the 4-week feeding trial. Sixty fresh eggs were collected and measured for egg quality within 24 h after collection. The other 480 eggs were used in a factorial arrangement with 5 dietary ASTA levels, 4 storage times, and 2 storage temperatures. During the 8-week storage period at 4°C and 25°C, egg quality measurements were performed every 2 wk on 12 eggs per treatment. No significant effects (P > 0.05) on yolk index, yolk pH, Haugh units, weight loss, or eggshell strength were observed with increasing concentrations of dietary ASTA. Yolk color darkened linearly with increasing dose of ASTA (P < 0.05). During storage of eggs, yolk index and Haugh units decreased significantly (P < 0.05), whereas yolk pH and weight loss increased (P < 0.05). An interaction was observed between dietary ASTA level and storage time on yolk index, yolk color, and Haugh units (P < 0.05). These results demonstrated that dietary ASTA from H. pluvialis delayed the decrease in yolk index and yolk color during storage at 4°C and 25°C. Therefore, we speculate that there may be a combined effect of dietary ASTA level and storage time on egg internal quality; this information may provide additional options by which to extend the storage time of eggs.

A Quantitative Analysis Model Established to Determine the Concentration of Each Source in Mixed Astaxanthin from Different Sources.

Astaxanthin from different sources possesses different biological activities and optical isomers. The ingredients of astaxanthin mixtures from different sources on the market have often been mislabeled. Therefore, it is important to determine the sources of astaxanthin and their respective concentrations in a mixture. To solve this problem, a quantitative analysis model was established and further verified. The results showed that the deviation between the calculated concentration and the actual concentration ranged from 0 to 7 µg/mL, and the recovery rate was between 88.90% and 103.56%. This indicates that the quantitative analysis model of astaxanthin was feasible and reliable. This study not only has important applications in the astaxanthin mixture component determination but may also shed light on the quantitative analysis of other sample mixtures with stereoisomers from different sources.

Mitochondrial Function, Mobility and Lifespan Are Improved in Drosophila melanogaster by Extracts of 9-cis-ß-Carotene from Dunaliella salina.

Carotenoids are implicated in alleviating ageing and age-related diseases in humans. While data from different carotenoids are mixed in their outcomes, those for 9-cis-ß-carotene indicate general positive effects, although basic data on its biological impact are limited. Here, we show that supplementation with 9-cis-ß-carotene in ageing Drosophila melanogaster improved mitochondrial function in terms of ATP production and whole-body respiration and extended mean lifespan. It also resulted in improved mobility. These data provide a potential biological rational for the beneficial effects of dietary supplementation with 9-cis-ß-carotene. These effects may be based on the maintenance of a sound mitochondrial function.

Thermal stability and oral absorbability of astaxanthin esters from Haematococcus pluvialis in Balb/c mice.

BACKGROUND: Astaxanthin is used as a functional nutraceutical and pigment in many food products. It is mostly exists in the form of a fatty acid ester in nature. However, no detailed descriptions are available concerning the stability and oral absorbability of astaxanthin esters. In the present study, the thermal stability and absorbability of astaxanthin esters from Haematococcus pluvialis were evaluated in comparison with free-form astaxanthin. RESULTS: The thermal stability of astaxanthin esters was found to be higher than that of free-form astaxantin. After gavage with astaxanthin esters, only free-form astaxanthin was detected in the digestive tract wall, blood plasma and liver, indicating that astaxanthin esters must be hydrolyzed to free-form astaxanthin in the gut before absorption. Furthermore, there was a considerable selective accumulation of different astaxanthin isomers in Balb/c mice, which selectivity decreased in the order: 13-cis > all-trans > 9-cis. Accumulated astaxanthin was mainly distributed in the heart, liver, spleen, muscle and adipose tissue, although significant differences between tissues were observed. CONCLUSION: From the present study, it can be concluded that astaxanthin esters had a higher thermal stability and higher bioavailability than free-form astaxanthin. These results provide important evidence with respect to using astaxanthin esters as bioactive components to replace free-form astaxanthin in functional food products. © 2019 Society of Chemical Industry.

Multifunctional green supramolecular solvents for cost-effective production of highly stable astaxanthin-rich formulations from Haematococcus pluvialis.

The interest of food industry to merchandise natural astaxanthin is growing up. However, it confronts scientific and technological challenges mainly related to its poor water solubility and chemical instability. Here, we present a new quick and efficient green process to simultaneously extract, encapsulate and stabilize astaxanthin from Haematococcus pluvialis. The process is based on the hitherto unexplored combination of supramolecular solvents (SUPRAS), nanostructured liquids generated from amphiphiles through sequential self-assembly and coacervation, and nanostructured lipid carriers (NLCs). These novel nanosystems were characterized by means of dynamic light scattering, AFM and cryoSEM, revealing spherical particles of ∼100 nm. Their antioxidant activity was measured by ORAC (20.6 ±â€¯3.9 µM TE) and α-TEAC (2.92 ±â€¯0.58 µM α-TE) assays and their in vitro capacity to inhibit ROS by DHE probe. Results showed that the SUPRAS-NLCs proposed yield high extraction and encapsulation efficiencies (71 ±â€¯4%) in combination with a remarkable time stability (180 d, 4 °C).

In situ biological CO2 fixation and wastewater nutrient removal with Neochloris oleoabundans in batch photobioreactor.

Microalgae cultivation in wastewater media in phototrophic condition is a promising approach for integrated CO2 biofixation and wastewater treatment. For this, Neochloris oleoabundans was used to investigate the tertiary treatment of wastewater along with CO2 biofixation. In this investigation, biomass productivity, CO2 biofixation rate and percentage of total nitrogen (TN) and total phosphorus (TP) removal from synthetic wastewater are considered under three different operating conditions: temperature, CO2 feed concentration and nitrogen to phosphorus (NP) ratio in the media. Cultivation of N. oleoabundans was found to be highly temperature sensitive. With the increase of cultivation temperature from 25 to 45 °C, declining trends of biomass concentration, productivity and percentage of TN and TP removal were observed. Cultivation temperature of 25 °C was found to be most favorable in terms of biomass productivity, CO2 biofixation rate, percentage of TN and TP removal of 92 (mg L-1 day-1), 145 (mg L-1 day-1), 100% and 32%, respectively. Arrhenius-type kinetic model was used and the model showed good agreement with the experimental findings. Activation energy for the active stage and decay stage was found to be [Formula: see text] = 88.8 kJ mol-1 and [Formula: see text] = 8.4 kJ mol-1, respectively. With the increase of CO2 feed concentration, biomass productivity increased and the maximum biomass concentration and productivity was achieved at 6%. After that with the increase in CO2, a declining trend was observed. With the increase of NP ratio from 1:1 to 2:1, both the biomass productivity and CO2 biofixation were increased, but later were subsequently decreased with increase of NP ratio from 4:1 to 8:1. It is interesting that TP removal was increased with NP ratio and 100 percent of TP removal was achieved at 4:1 and 8:1 conditions.

Astaxanthin Prevents Human Papillomavirus L1 Protein Binding in Human Sperm Membranes.

Astaxanthin (Asta), red pigment of the carotenoid family, is known for its anti-oxidant, anti-cancer, anti-diabetic, and anti-inflammatory properties. In this study, we evaluated the effects of Asta on isolated human sperm in the presence of human papillomavirus (HPV) 16 capsid protein, L1. Sperm, purified by gradient separation, were treated with HPV16-L1 in both a dose and time-dependent manner in the absence or presence of 30 min-Asta pre-incubation. Effects of HPV16-L1 alone after Asta pre-incubation were evaluated by rafts (CTB) and Lyn dislocation, Tyr-phosphorylation (Tyr-P) of the head, percentages of acrosome-reacted cells (ARC) and endogenous reactive oxygen species (ROS) generation. Sperm membranes were also analyzed for the HPV16-L1 content. Results show that HPV16-L1 drastically reduced membrane rearrangement with percentage of sperm showing head CTB and Lyn displacement decreasing from 72% to 15.8%, and from 63.1% to 13.9%, respectively. Accordingly, both Tyr-P of the head and ARC decreased from 68.4% to 10.2%, and from 65.7% to 14.6%, respectively. Asta pre-incubation prevented this drop and restored values of the percentage of ARC up to 40.8%. No alteration was found in either the ROS generation curve or sperm motility. In conclusion, Asta is able to preserve sperm by reducing the amount of HPV16-L1 bound onto membranes.

CO2 bio-fixation and biofuel production in an airlift photobioreactor by an isolated strain of microalgae Coelastrum sp. SM under high CO2 concentrations.

Microalgae cultivation is a promising approach to remove ambient CO2 via photosynthesis process. This paper investigates the impact of high CO2 concentrations (6, 12, and 16%) on algae growth, CO2 biofixation, lipid and carbohydrate contents, and nutrient removal of newly isolated microalgae, Coelastrum sp. SM. In addition, the ability of microalgae to produce biodiesel at optimal condition was studied. The microalgae were cultivated in wastewater using an airlift photobioreactor. Under 12% CO2, the maximum biomass productivity and CO2 fixation rate were 0.267 g L-1 day-1 and 0.302 g L-1 h-1, respectively. Total Kjeldahl nitrogen (TKN), total phosphorous (TP), nitrate, and sCOD removal efficiency were 84.01, 100, 86.811, and 73.084%, respectively. Under 12% CO2 and at the same condition for cell growth, the highest lipid and carbohydrate contents were 3 7.91 and 58.45%, respectively. The composition of fatty acids methyl ester (FAME) of the microalga lipid was defined. Based on the obtained results and FAME profile, Coelastrum sp. SM was a suitable feedstock for biodiesel production and also, the organism had a great potential for CO2 biofixation, which is also more suitable than any other reported strains in other related studies.

Effects of astaxanthin on biochemical and histopathological parameters related to oxidative stress on testes of rats on high fructose regime.

Astaxanthin (ASX) is a xanthophyll family of hydroxycarotenoids which contains several double bonds. It is produced by Haemococcus pluvialis, a microalgae and possesses antioxidant and anti-inflammatory properties. The aim of this study was to test whether ASX could protect against oxidative damage in the testicular tissues of rats receiving high fructose. The rats (n = 24) were randomly divided into two main groups: control and fructose (30%, via drinking water) and then each main group either not supplemented or supplemented with ASX (1 mg kg-1 day-1 , within 0.2 ml olive oil) via oral gavage. Data were subjected to two-way ANOVA. High fructose consumption tended to increase testis weight and serum testosterone concentration and decreased testicular tissue glutathione-S-transferase (GST) and superoxide dismutase (SOD) levels, but did not affect testicular tissue malondialdehyde (MDA) concentration. Astaxanthin administration increased testosterone, GST and SOD levels and testis weight and decreased MDA concentration. However, ASX administration did not reverse alterations in antioxidant parameters caused by high fructose consumption. Inducible nitric oxide synthase (iNOS) tended to increase in sertoli cell, spermatid and spermatogonia, but not in spermatocytes and leydig cell in response to high fructose consumption. Astaxanthin administration tended to reverse elevation in iNOS in testis cells. In conclusion, ASX could help alleviate oxidative damage caused by high fructose consumption.