Spirulina maxima Extract Ameliorates Learning and Memory Impairments via Inhibiting GSK-3ß Phosphorylation Induced by Intracerebroventricular Injection of Amyloid-ß 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-ß 1-42 (Aß1-42) 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 Aß1-42 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 Aß1-42-injected mice. SM70EE reduced hippocampal Aß1-42 levels and inhibited amyloid precursor protein processing-associated factors in Aß1-42-injected mice. Additionally, acetylcholinesterase activity was suppressed by SM70EE in Aß1-42-injected mice. Hippocampal glutathione levels were examined to determine the effects of SM70EE on oxidative stress in Aß1-42-injected mice. SM70EE increased the levels of glutathione and its associated factors that were reduced in Aß1-42-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-3ß phosphorylation. These findings suggested that SM70EE ameliorated Aß1-42-induced cognitive impairments by inhibiting the increased phosphorylation of glycogen synthase kinase-3ß caused by intracerebroventricular injection of Aß1-42 in mice.

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 AMPresponsive elementbinding 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.

Spirulina maxima extract prevents cell death through BDNF activation against amyloid beta 1-42 (Aß1-42) 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 Aß1-42-induced neurotoxicity in PC12 cells. The aim of this study was to investigate whether SM70EE, chlorophyll a, and C-PC prevent Aß1-42-induced cell death. SM70EE, chlorophyll a, and C-PC suppressed the Aß1-42-induced increase in poly-ADP ribose polymerase-1 (PARP-1) cleavage and reduced Aß1-42-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 Aß1-42-treated cells. SM70EE treatment decreased oxidative stress and cell death in response to Aß1-42 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 Aß1-42-induced neurotoxicity in PC12 cells. We suggest that SM70EE prevents cell death caused by Aß1-42 -induced neurotoxicity via the activation of BDNF signaling.