Spirulina Maxima Research Articles

Enhancement of the Neuroprotective Effect of Fermented Spirulina maxima Associated with Antioxidant Activities by Ultrasonic Extraction

This study is the first demonstration of the neuroprotective activity of the marine alga, Spirulina maxima, fermented by Lactobacillus plantarum HY-08, which was freshly isolated from fermented vegetables. The combined process of the fermentation with ultrasonic extraction at 40 kHz for 4 hr greatly increased the amounts of β-carotene in the extract up to 1.62 mg/g, along with a high extraction yield of 18.26%, compared to 1.03 mg/g and 12.8% from ultrasonic extraction itself, and even much higher than 0.81 mg/g and 10.6% from conventional water extraction. It was also proved that the neuroprotective activities of the extract were enhanced possibly by higher contents of β-carotene in the extract, compared to those from water extraction or ultrasonic extraction itself. This extract was found to have strong antioxidant properties, with 49.01% 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, which resulted in 90.30% neuroprotective activity. Specifically, the fermented extract markedly enhanced the brain-derived neurotrophic factor (BDNF)/p-CREB signaling pathways, which can effectively prevent memory impairment in mice caused by oxidative stress. β-Carotene also increased the expression of p-CREB and BDNF, and a mechanism of their upregulation by β-carotene is first proposed in this study. It can be concluded that the strong neuroprotective effect of the extract was markedly influenced by the antioxidant activities, due to the synergistic effects of high amounts of β-carotene and other biologically active substances in the extract that can be obtained by lactic acid fermentation, combined with ultrasonic processing.

Statistical Optimization of Spirulina Maxima Loaded Microspheres and Assessment of Antioxidant, Antidiabetic Potential in Glycemic Abnormalities Induced Wistar Rats by Excessive Fructose Administration

Statistical Optimization of Spirulina Maxima Loaded Microspheres and Assessment of Antioxidant, Antidiabetic Potential in Glycemic Abnormalities Induced Wistar Rats by Excessive Fructose Administration

Remediation of methylene blue from aqueous solution by Chlorella pyrenoidosa and Spirulina maxima biosorption: Equilibrium, kinetics, thermodynamics and optimization studies

The present work aimed to investigate the equilibrium, kinetics and thermodynamic viability of methylene blue (MB) biosorption by Chlorella pyrenoidosa (C. pyrenoidosa) and Spirulina maxima (S. maxima). A comprehensive characterization of both dried biomasses used as biosorbent was carried out and the parameters involved were optimized for maximum MB removal efficiency. Thermogravimetric analysis showed that both algae are constituted mainly of proteins and carbohydrates. The infrared spectra suggested a physical biosorption mechanism for both algae that was later proven by the enthalpy change and the Dubinin–Radushkevich isotherm model. Furthermore, the process involving S. maxima was best described by Freundlich (R2 = 0.995, χ2 = 1.246) and Temkin (R2 = 0.999, χ2 = 0.155) isotherm models, indicating the formation of multiple layers and the linear reduction of the heat of biosorption with the coverage degree. Biosorption onto C. pyrenoidosa was best described by Langmuir isotherm model (R2 = 0.993, χ2 = 0.126), indicating the monolayer predominance. C. pyrenoidosa presented a maximum biosorption capacity of 101.75 mg g−1, in contrast to 145.34 mg g−1 for S. maxima. The pseudo second order kinetic model was the best fit for C. pyrenoidosa (R2 = 0.999, χ2 = 0.004) and S. maxima (R2 = 0.999, χ2 = 0.014). The model optimization was achieved in order to maximize the removal efficiency, corresponding to 98.20% for C. pyrenoidosa and 94.19% for S. maxima.

Beneficial effects of phycobiliproteins from Spirulina maxima in a preeclampsia model

AimsConsidering phycobiliproteins of Spirulina maxima has shown a wide margin of security in pregnant and non-pregnant animals as well as antioxidant properties, present study aimed to investigate if the cardiovascular and metabolic effects of an experimental model of preeclampsia can be prevented by the administration of this compound. Main methodsSubrenal aortic coarctation (SRAC) practiced to female Wistar rats of 8 weeks of age. Animals were divided randomly to conform non-pregnant and pregnant groups and pregnant with SRAC showed fetoplacental ischemia and were considered preeclamptic (PE). Groups were treated with saline solution (control group) or phycobiliproteins solution (100 mg/kg/day ig) for the last 7, 14 or 20 days of pregnancy. Key findingsPE animals showed increased systolic blood pressure, weight gain, glucose and GTT as well as vascular contractility. Also, PE animals showed decreased SOD, GPx activities while MDA was increased. Phycobiliproteins oral treatment for 3 weeks significantly decreased systolic blood pressure and reestablished glucose, weight gain and vascular contractility as well as enzyme activities of PE rats to those of normal pregnant animals. SignificanceOur results show that phycobiliproteins can prevent the damage produced by fetoplacental ischemia and provides evidence of free radical species contribution to the physiopathology of the disease. Also, we conclude phycobiliproteins can be an alternative to reduce preeclampsia manifestations, however, more studies are recommended.

Enhancement of Neuroprotective Effects of Spirulina maxima by a Low-temperature Extraction Process with Ultrasonic Pretreatment

17.5 ± 2.41 mg/g and 15.2 ± 2.09 mg/g of total chlorophyll and chlorophyll a, respectively, were obtained from the marine microalga, Spirulina maxima under an optimal extraction condition of 70% ethanol at 65°C for 4 h associated with ultrasonic pretreatment at 40 kHz for 8 h. In comparison, 14.5 ± 1.36 mg/g and 7.1 ± 0.99 mg/g of total chlorophyll and chlorophyll a, respectively, were obtained from a conventional extraction process using 70% ethanol at 80°C for 12 h. The extract from the optimal conditions had the highest ratio of chlorophyll a to total chlorophyll, approximately 3:4, indicating that more intact chlorophyll a was obtained at low temperature. Moreover, the extract obtained using the optimal extraction condition showed substantial neuroprotective effects such as 92.78 ± 0.04% protection against glutamate-induced mouse hippocampal neuronal cells, compared to 81.64 ± 0.07% protection with the extract from the conventional extraction process. Compared to the control, the activities of two key enzymes related to glutathione synthesis, i.e., glutathione reductase and glutathione peroxidase, were also strongly increased, up to 90%, by the extracts from the optimal conditions. Interestingly, the addition of the same concentration of chlorophyll a as in the optimized extract had lower neuroprotective effects than did the extracts. This finding indicates that the extract likely exerted a synergistic effect, showing that the extract had better neuroprotective activity than the single component (chlorophyll a) alone. This work also confirmed the neuroprotective mechanism of the extract mainly due to its high antioxidant activity, allowing it to greatly decrease accumulation of ROS and Ca2+ within HT22 cells. The results of this work will have implications for expanding the use of a nonthermal ultrasonic process to extract heat-sensitive bioactive substances from natural resources.

Spirulina maxima peptides suppress mast cell degranulation via inactivating Akt and MAPKs phosphorylation in RBL-2H3 cells

In this study, the suppressive effects of peptides P1 (LDAVNR) and P2 (MMLDF) from enzymatic hydrolysate of Spirulina maxima on mast cell degranulation was elucidated. It was revealed that P1 and P2 exhibited significant inhibition on cell degranulation via decreasing β-hexosaminidase release at concentration of 200 μM. Moreover, the inhibitory effects of P1 and P2 on expression and production of interleukin (IL)-13 were evidenced. Furthermore, peptide treatment caused a remarkable inhibition on the phosphorylation of Akt and mitogen-activated protein kinases (MAPKs) including ERK, p38, and JNK. Notably, the inhibitory activity of P1 on cell degranulation was found due to blockade of FcεRI receptor. Meanwhile, the inhibitory activity of P2 was involved in alleviation of intracellular reactive oxygen species (ROS) production. Collectively, peptides P1 and P2 from S. maxima were suggested to be promising inhibitors of mast cell degranulation, contributing to the development of bioactive ingredients for amelioration of allergic diseases.

Biomass of Microalgae Spirulina Maxima as a Corrosion Inhibitor for 1020 Carbon Steel in Acidic Solution.

Biomass of Microalgae Spirulina Maxima as a Corrosion Inhibitor for 1020 Carbon Steel in Acidic Solution.

Amelioration of Ethanol-Induced Gastric Ulcers in Rats Pretreated with Phycobiliproteins of Arthrospira (Spirulina) Maxima.

Phycobiliproteins of Arthrospira (Spirulina) maxima have attracted attention because of their potential therapeutic antioxidant properties. The aim of this study was to assess the possible antiulcerogenic activity of these phycobiliproteins (ExPhy) against ethanol-induced gastric ulcers in rats. To explore the possible mechanisms of action, we examined antioxidant defense enzymes (e.g., catalase, superoxide dismutase, and glutathione peroxidase), as well as the level of lipid peroxidation (MDA) and the histopathological changes in the gastric mucosa. Intragastric administration of ExPhy (100, 200, and 400 mg/kg body weight) significantly lowered the ulcer index value compared to the ulcer control group (p < 0.05). The greatest protection was provided by the concentration of 400 mg/kg. The histological study supported the observed gastroprotective activity of ExPhy, showing a reduced inflammatory response. Moreover, the alcohol-induced decrease in stomach antioxidant enzyme activity found in the ulcer control group was prevented by ExPhy pretreatment. Furthermore, ExPhy reversed the ethanol-induced increase in lipid peroxidation. In summary, the antiulcerogenic potential of ExPhy may be due, at least in part, to its anti-oxidant and anti-inflammatory effects.

Spirulina maxima Extract Reduces Obesity through Suppression of Adipogenesis and Activation of Browning in 3T3-L1 Cells and High-Fat Diet-Induced Obese Mice.

Obesity predisposes animals towards the metabolic syndrome and diseases such as type 2 diabetes, atherosclerosis, and cardiovascular disease. Spirulina maxima is a microalga with anti-oxidant, anti-cancer, and neuroprotective activities, but the anti-obesity effect of Spirulina maxima 70% ethanol extract (SM70EE) has not yet been fully established. We investigated the effect of SM70EE on adipogenesis, lipogenesis, and browning using in vitro and in vivo obesity models. SM70EE treatment reduced lipid droplet accumulation by the oil red O staining method and downregulated the adipogenic proteins C/EBPα, PPARγ, and aP2, and the lipogenic proteins SREBP1, ACC, FAS, LPAATβ, Lipin1, and DGAT1 by western blot analysis. In addition, the index components of SM70EE, chlorophyll a, and C-phycocyanin, reduced adipogenesis and lipogenesis protein levels in 3T3-L1 and C3H10T1/2 cells. High-fat diet (HFD)-fed mice administered with SM70EE demonstrated smaller adipose depots and lower blood lipid concentrations than control HFD-fed mice. The lower body mass gain in treated SM70EE-administrated mice was associated with lower protein expression of adipogenesis factors and higher expression of AMPKα-induced adipose browning proteins PRDM16, PGC1α, and UCP1. SM70EE administration ameliorates obesity, likely by reducing adipogenesis and activating the thermogenic program, in 3T3-L1 cells and HFD-induced obese mice.

Eclosión de huevos de artemia (Artemia franciscana Kellogg) a nivel de laboratorio en la Universidad Nacional Agraria, Managua, Nicaragua

En el estudio de eclosión de Artemia franciscana a nivel de laboratorio, tuvo como objetivo determinar el tipo de tratamiento que se adapta a condiciones de laboratorio brindando buenos resultados para la eclosión del crustáceo Artemia (Artemia franciscana Kellogg). La metodología utilizada consistió en la toma de datos en el laboratorio evaluando los siguientes tratamientos: Toma de pH; Toma de temperatura; Salinidad y Medición de Sobrevivencia. Una vez establecido el ensayo se procedió a colocar los huevo de Artemia, dejándolos por un periodo de 48 horas para iniciar el proceso eclosivo del crustáceo. El manejo que se aplicó en el estudio consistió en tomar datos de temperatura y del pH para llevar un control y seguimiento a la eclosión de Artemia; así como el control de la alimentación a base de una dieta de pastilla de alga Spirulina máxima triturada. De acuerdo al análisis estadístico realizado con metodología de DUNCAN, correlación de Pearson y procesado en el programa estadístico INFOSTAT indican que la mejor eclosión se registró en el tratamiento D con un 65.40 % dando pautas de ser el tratamiento que mejor se adaptó a las condiciones de laboratorio. La sobrevivencia de los otros tratamientos es positiva y adaptable a condiciones de laboratorio donde es recomendable utilizar recipientes con mayor capacidad de almacenamiento de agua. Recomendándose para futuros cultivos de Artemia llevar a cabo el manejo ya implementado en el Laboratorio de Ciencias Biológicas de la Universidad Nacional Agraria para un mayor rendimiento en la sobrevivencia del estudio y seguir proporcionando información para la eclosión de dicho crustáceo que representa una opción alimenticia de bajo impacto a productores pesqueros del país.

Pyrolysis of Spirulina maxima: Kinetic modeling and selectivity for aromatic hydrocarbons

Microalgae, such as Spirulina maxima biomass is considered a potential raw material for fast pyrolysis process due to its low-lipid and high-protein contents. Aromatic hydrocarbons, which are widely used in industry, are the main derivatives of protein pyrolysis. In this study, thermogravimetric analyses were performed and activation energy values were identified using three methodologies: Friedman and Flynn-Wall-Ozawa isoconversional methods, Miura-Maki distributed activation energy model and the model of independent parallel reactions. The mean values of activation energy were 132.62, 143.77 and 136.89 kJ/mol, respectively, for the Flynn-Wall-Ozawa, Friedman and Miura-Maki models. The biomass pyrolysis was described by two different reactions using the independent parallel reactions model and the mean values of activation energy were between 48.58 and 51.52 kJ/mol for the mass fraction essentially composed by carbohydrate and between 143.61 and 288.55 kJ/mol for the mass fraction with protein as the main component. The micro-pyrolysis of the pure biomass was analyzed at different reaction temperatures (723, 823 and 923 K). At 923 K the highest yield of aromatic hydrocarbons and a decrease in oxygenated compounds were observed. Catalytic micro-pyrolysis was performed for Spirulina maxima using either zeolite HZSM-5 or niobic acid (HY-340) as catalysts. For HZSM-5, the biomass-to-catalyst ratio of 1:10 increased more than five times the production of hydrocarbons when compared to the pure biomass. The niobium-based catalyst (HY-340) did not present a significant effect on the production of these value-added compounds. Probably, for HY-340, the active sites are not predominantly Brønsted acid sites and/or the number of Brønsted acid sites was not sufficient to promote the production of aromatics. The present work is one of the first studies considering niobic acid as a catalyst for biomass pyrolysis and using the independent parallel reactions model for the determination of kinetic parameters for Spirulina maxima.

Adaptive high gain observer extension and its application to bioprocess monitoring

The adaptive version of the high gain observer for the strictly triangular systems subjected to constant unknown disturbances is proposed here. The adaptive feature is necessary due to the fact that the unknown disturbance enters in a way that cannot be suppressed by the high gain technique. The developed observers are then applied to a culture of microorganism in a bioreactor, namely, to the model of the continuous culture of Spirulina maxima. It is a common practice that just the biomass (or substrate) concentration is directly measured as the output of the process for monitoring and control purposes. This paper thereby shows both by theoretical analysis and numerical simulation that the adaptive high-gain observers offer a realistic option of online software sensors for substrate estimation.

Spirulina maxima extract prevents cell death through BDNF activation against amyloid beta 1-42 (Aβ1-42) induced neurotoxicity in PC12 cells

Spirulina maxima is a blue-green micro alga that contains abundant amounts of proteins (60–70%), vitamins, chlorophyll a, and C-phycocyanin (C-PC). It has been shown to reduce oxidative stress, and prevent diabetes and non-alcoholic fatty liver disease. However, it is unclear whether Spirulina maxima 70% ethanol extract (SM70EE), chlorophyll a, and C-PC prevent Aβ1-42-induced neurotoxicity in PC12 cells. The aim of this study was to investigate whether SM70EE, chlorophyll a, and C-PC prevent Aβ1-42-induced cell death. SM70EE, chlorophyll a, and C-PC suppressed the Aβ1-42-induced increase in poly-ADP ribose polymerase-1 (PARP-1) cleavage and reduced Aβ1-42-induced decreases in glutathione and its associated factors. The level of brain-derived neurotrophic factor (BDNF), which plays a critical role in neuronal survival and neuroprotection, was increased by SM70EE, chlorophyll a, and C-PC in Aβ1-42-treated cells. SM70EE treatment decreased oxidative stress and cell death in response to Aβ1-42 treatment, while simultaneously suppressing PARP cleavage and increasing the levels of glutathione (GSH) and its associated factors. Moreover, SM70EE lowered the levels of APP and BACE1, two major factors involved in APP processing, and increased BDNF expression during Aβ1-42-induced neurotoxicity in PC12 cells. We suggest that SM70EE prevents cell death caused by Aβ1-42 −induced neurotoxicity via the activation of BDNF signaling.

Effect of Fermented Spirulina maxima Extract on Cognitive-Enhancing Activities in Mice with Scopolamine-Induced Dementia.

This work provides the first demonstration that Spirulina maxima extract fermented with the lactic acid bacterium Lactobacillus planetarium HY-08 has the ability to ameliorate scopolamine-induced memory impairment in mice. The fermented extract exhibited good cognitive-enhancing activities, as demonstrated through Morris water maze and passive avoidance experiments: in these tests, the mice administered the fermented extract at a dose of 400 mg/kg exhibited an escape latency time and a latency time of 88.5 and 76.0 sec, respectively, whereas those administered donepezil, which was used as a positive control, showed an escape latency time and a latency time of 81.3 and 83.3 sec, respectively. However, an extract of 200 mg/kg was considered economically feasible for maintaining relatively high memory-improving activities because only a slight difference in activities was found between 200 and 400 mg/kg. The study also provides the first demonstration that β-carotene, one of the major bioactive substances in S. maxima, has memory-enhancing activity. A detailed analysis of the mechanism for the cognitive-enhancing activities of the fermented extract revealed that the fermented extract effectively increased the phosphorylation of both extracellular signal-regulated kinases (p-ERK) and p-cAMP response element-binding protein (p-CREB) and sequentially upregulated the expression of brain-derived neurotrophic factor (BDNF), whose signaling pathway responds to a reduction in oxidative stress in the brain. The results indicate that the improved efficacy of the fermented extract was likely due to the synergistic effects of β-carotene and other bioactive substances. Therefore, it can be concluded that the fermented extract exerts memory-improving effects in the hippocampus of scopolamine-treated mice through an initial increase in ERK signaling and a sequential induction of the expression of p-CREB and BDNF, and these effects are related to the antioxidant activities of β-carotene and other components.

Protective Effect of Water Extracted Spirulina maxima on Glutamate-induced Neuronal Cell Death in Mouse Hippocampal HT22 Cell.

Introduction:Spirulina maxima was used as important nutritional source in the Aztec civilization because it is rich in proteins and vitamins. It contains various antioxidants such as phycocyanin and flavonoids. Based on abundant antioxidants, S. maxima is known to possess anti-inflammatory effect, especially on neuronal cells.Materials and Methods:S. maxima was extracted in water and contain of phycocyanin was identified by high-performance liquid chromatography. Cell viability test was performed with treatment of S. maxima extract. After, oxidative stress-related mechanisms were evaluated by detecting the accumulation of reactive oxygen species (ROS) and Ca2+ influx, and decrease of mitochondrial membrane potential (MMP) level. Then, the glutathione (GSH) related assays were conducted.Results:The water extracted S. maxima exerted the neuroprotective activity by attenuating the ROS and Ca2+ formation, maintaining the MMP level, and protecting the activity of the antioxidant enzymes by increasing reduced GSH against oxidative stress compared to control.Conclusion:The results suggested that water extracted S. maxima showed powerful neuroprotective effect through the mechanism related to antioxidant activity, able to preventing the radical-mediated cell death.SUMMARY Water extracted Spirulina maxima contains C-phycocyaninWater extracted Spirulina maxima exerts neuroprotective effect on HT22 cellTo investigate the protective mechanisms, reactive oxygen species, Ca2+, mitochondrial membrane potential, Glutathione-related assays were performed. Abbreviations used: ROS: Reactive oxygen species; MMP: Mitochondrial membrane potential; GSH: Glutathione; GSSG: Glutathione disulfide, oxidized glutathione; GPx: Glutathione peroxidase; GR: Glutathione reductase; DMEM: Dulbecco's modified Eagle's medium; FBS: Fetal bovine serum; DCF-DA: 2',7'-dichlorofluorescein diacetate; PBS: Phosphate buffered serum; Rho 123: Rhodamine 123; NADPH: Nicotinamide adenine dinucleotide phosphate; DTNB: 5,5'-dithiobis-2-nitrobenzoic acid, Ellman's reagent; GSSG-R: Glutathione disulfide reductase; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; DMSO: Dimethyl sulfoxide; HPLC: High-performance liquid chromatography.

Enhancement of Chlorophyll a Production from Marine Spirulina maxima by an Optimized Ultrasonic Extraction Process

Under the optimal ultrasonification extraction conditions of 20.52 kHz for the frequency, 32.59 °C for the temperature, and 4.91 h for the process time, 17.98 mg/g of chlorophyll a was obtained. It was much higher than 13.81 mg/g from conventional 70% ethanol extraction and even higher than other data from Spirulina. This yield was close to the predicted value of 18.21 mg/g from the second-order polynomial model with a regression coefficient of 0.969. This model showed the greatest significance with the ultrasonic frequency and process time and the least significance with the temperature. The extracts also showed high α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activities as 69.38%, compared to 58.25% for the extracts from the 70% ethanol extraction. It was first shown that the optimal extraction was effective at enhancing the neuroprotective activities possibly due to the synergistic effects of higher amounts of chlorophyll a and other bioactive substances in the extract, revealing a 90% protection of the growth of mouse neuronal cells and a great reduction in Reactive Oxygen Species (ROS) production.

Spirulina Extract Enhanced a Protective Effect in Type 1 Diabetes by Anti-Apoptosis and Anti-ROS Production.

Interest in the nutritional value and pharmacological activities of blue-green algae has gradually increased. Spirulina extracts show protective effects against apoptosis and inflammatory damage in various cell types. Here, we investigated the protective effects of extracts from Spirulina maxima in a cytokine-mediated type 1 diabetes model in vitro and in streptozotocin-induced diabetic Wistar rats in vivo. Interleukin-1β and interferon-gamma induced substantial cytotoxicity to RINm5F rat insulinoma cells, increasing nitric oxide (NO) production, nuclear factor-kappa B (NF-κB) activity, the expression of endoplasmic reticulum (ER) stress genes, and activation of mitogen-activated protein kinases and key genes related apoptosis. However, the cytotoxicity of cytokines was significantly attenuated by Spirulina extract, which effectively prevented NO production by inhibiting the synthesis of cytokine-activated NO synthase (iNOS), and apoptosis was suppressed. These results suggest that Spirulina extract might be effective to preserve the viability and function of pancreatic β-cells against cytotoxic conditions. Moreover, diabetic mice orally administered Spirulina extract showed decreased glucose levels, increased insulin, and improvement in liver enzyme markers. The antioxidant effect of Spirulina extract may be helpful in treating type 1 diabetes by enhancing the survival, and reducing or delaying cytokine-mediated β-cells destruction.

Spirulina maxima Extract Ameliorates Learning and Memory Impairments via Inhibiting GSK-3β Phosphorylation Induced by Intracerebroventricular Injection of Amyloid-β 1-42 in Mice.

Spirulina maxima, a microalga containing high levels of protein and many polyphenols, including chlorophyll a and C-phycocyanin, has antioxidant and anti-inflammatory therapeutic effects. However, the mechanisms where by Spirulina maxima ameliorates cognitive disorders induced by amyloid-β 1–42 (Aβ1–42) are not fully understood. In this study, we investigated whether a 70% ethanol extract of Spirulina maxima (SM70EE) ameliorated cognitive impairments induced by an intracerebroventricular injection of Aβ1–42 in mice. SM70EE increased the step-through latency time in the passive avoidance test and decreased the escape latency time in the Morris water maze test in Aβ1–42-injected mice. SM70EE reduced hippocampal Aβ1–42 levels and inhibited amyloid precursor protein processing-associated factors in Aβ1–42-injected mice. Additionally, acetylcholinesterase activity was suppressed by SM70EE in Aβ1–42-injected mice. Hippocampal glutathione levels were examined to determine the effects of SM70EE on oxidative stress in Aβ1–42-injected mice. SM70EE increased the levels of glutathione and its associated factors that were reduced in Aβ1–42-injected mice. SM70EE also promoted activation of the brain-derived neurotrophic factor/phosphatidylinositol-3 kinase/serine/threonine protein kinase signaling pathway and inhibited glycogen synthase kinase-3β phosphorylation. These findings suggested that SM70EE ameliorated Aβ1–42-induced cognitive impairments by inhibiting the increased phosphorylation of glycogen synthase kinase-3β caused by intracerebroventricular injection of Aβ1–42 in mice.

Enhancement of antioxidant activity of C-phycocyanin of Spirulina powder treated with supercritical fluid carbon dioxide

The functionality and activity of proteins can be modified by supercritical fluid CO2 (SCFCO2). The objectives of this study were to investigate the possibility of enhanced antioxidant activity of C-phycocyanin (C-PC) proteins from light-harvested Spirulina maxima powder using the SCFCO2 pretreatment and to optimize the SCFCO2 pretreatment conditions enhancing the antioxidant activity of C-PC. The Taguchi method was used to determine the optimum conditions for the SCFCO2 pretreatment. The experimental factors were the pretreatment temperature, pressure, pretreatment mode (static, dynamic and conjugated) and duration. The optimal conditions of SCFCO2 pretreatment were: 60 °C, 24.13 MPa and 60 min in static batch mode. Using these pretreatment conditions, the maximum antioxidant activity of C-PC from the treated residual biomass was 410.1 μmole trolox/mg, which was 1.7-fold higher than the untreated biomass (control). The factor that most affected the antioxidant activity of C-PC was temperature (59%). A high pretreatment temperature could damage C-PC, but promoted antioxidant activity. Of note is that this work was the first to explore SCFCO2 treatment enhancing the antioxidant activity of C-PC in Spirulina sp. powder.

Spirulina maxima Extract Prevents Neurotoxicity via Promoting Activation of BDNF/CREB Signaling Pathways in Neuronal Cells and Mice.

Spirulina maxima is a microalgae which contains flavonoids and other polyphenols. Although Spirulina maxima 70% ethanol extract (SM70EE) has diverse beneficial effects, its effects on neurotoxicity have not been fully understood. In this study, we investigated the neuroprotective effects of SM70EE against trimethyltin (TMT)-induced neurotoxicity in HT-22 cells. SM70EE inhibited the cleavage of poly-ADP ribose polymerase (PARP). Besides, ROS production was decreased by down-regulating oxidative stress-associated enzymes. SM70EE increased the factors of brain-derived neurotrophic factor (BDNF)/cyclic AMP-responsive element-binding protein (CREB) signalling pathways. Additionally, acetylcholinesterase (AChE) was suppressed by SM70EE. Furthermore, we investigated whether SM70EE prevents cognitive deficits against scopolamine-induced neurotoxicity in mice by applying behavioral tests. SM70EE increased step-through latency time and decreased the escape latency time. Therefore, our data suggest that SM70EE may prevent TMT neurotoxicity through promoting activation of BDNF/CREB neuroprotective signaling pathways in neuronal cells. In vivo study, SM70EE would prevent cognitive deficits against scopolamine-induced neurotoxicity in mice.