Rhamnan Sulfate from the Seaweed <i>Monostroma nitidum</i> May Improve Cognitive Impairment Caused by Hyperglycemia

Rhamnan sulfate (RS), extracted from the seaweed <i>Monostroma nitidum</i>, suppresses vascular endothelial inflammation and arteriosclerosis, decreases blood glucose levels, and improves blood lipid metabolism and the intestinal environment. We examined whether RS improves hyperglycemia...

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Main Authors: Takaichi Miwa, Masaya Sato, Ning Ma, Keiichi Hiramoto, Masahiro Terasawa, Koji Suzuki
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Marine Drugs
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Online Access:https://www.mdpi.com/1660-3397/23/6/250
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author Takaichi Miwa
Masaya Sato
Ning Ma
Keiichi Hiramoto
Masahiro Terasawa
Koji Suzuki
author_facet Takaichi Miwa
Masaya Sato
Ning Ma
Keiichi Hiramoto
Masahiro Terasawa
Koji Suzuki
author_sort Takaichi Miwa
collection DOAJ
description Rhamnan sulfate (RS), extracted from the seaweed <i>Monostroma nitidum</i>, suppresses vascular endothelial inflammation and arteriosclerosis, decreases blood glucose levels, and improves blood lipid metabolism and the intestinal environment. We examined whether RS improves hyperglycemia-induced cognitive decline in a hyperglycemic mouse model pretreated with nicotinamide and streptozotocin and then orally administered a high-fat diet and maltodextrin (MD) for 4 months. RS was administered in an MD solution at doses of 75, 225, and 750 mg/kg of mouse body weight. Administration of RS to hyperglycemic mice significantly reduced blood glucose levels and tended to improve memory function in behavioral pharmacological tests using spontaneous locomotor activity, rotarod test, and eight-way-maze test, although the results were not significant. Brain histopathological analysis showed that RS significantly reduced atrophy of neuronal layers in each region of the hippocampus compared with untreated hyperglycemic controls. RS also significantly suppressed TNF-α expression and microglial activation in the brain. These results suggest that RS intake suppresses inflammation in the brain and alleviates the cognitive impairment associated with hyperglycemic diabetes.
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institution Kabale University
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publisher MDPI AG
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spelling doaj-art-f4bc65a2534544febbec2801ee8fe2852025-08-20T03:27:37ZengMDPI AGMarine Drugs1660-33972025-06-0123625010.3390/md23060250Rhamnan Sulfate from the Seaweed <i>Monostroma nitidum</i> May Improve Cognitive Impairment Caused by HyperglycemiaTakaichi Miwa0Masaya Sato1Ning Ma2Keiichi Hiramoto3Masahiro Terasawa4Koji Suzuki5Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Minamitamagakicho 3500-3, Suzuka 513-8670, Mie, JapanFaculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Minamitamagakicho 3500-3, Suzuka 513-8670, Mie, JapanGraduate School of Health Science, Suzuka University of Medical Science, Kishioka-cho 1275-3, Suzuka 510-0226, Mie, JapanFaculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Minamitamagakicho 3500-3, Suzuka 513-8670, Mie, JapanKonan Chemical Manufacturing Co., Ltd., Kitagomizuka, Kusu-cho, Yokkaichi 510-0103, Mie, JapanFaculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Minamitamagakicho 3500-3, Suzuka 513-8670, Mie, JapanRhamnan sulfate (RS), extracted from the seaweed <i>Monostroma nitidum</i>, suppresses vascular endothelial inflammation and arteriosclerosis, decreases blood glucose levels, and improves blood lipid metabolism and the intestinal environment. We examined whether RS improves hyperglycemia-induced cognitive decline in a hyperglycemic mouse model pretreated with nicotinamide and streptozotocin and then orally administered a high-fat diet and maltodextrin (MD) for 4 months. RS was administered in an MD solution at doses of 75, 225, and 750 mg/kg of mouse body weight. Administration of RS to hyperglycemic mice significantly reduced blood glucose levels and tended to improve memory function in behavioral pharmacological tests using spontaneous locomotor activity, rotarod test, and eight-way-maze test, although the results were not significant. Brain histopathological analysis showed that RS significantly reduced atrophy of neuronal layers in each region of the hippocampus compared with untreated hyperglycemic controls. RS also significantly suppressed TNF-α expression and microglial activation in the brain. These results suggest that RS intake suppresses inflammation in the brain and alleviates the cognitive impairment associated with hyperglycemic diabetes.https://www.mdpi.com/1660-3397/23/6/250diabetic cognitive impairmenthippocampal atrophymicrogliarhamnan sulfate<i>Monostroma nitidum</i>
spellingShingle Takaichi Miwa
Masaya Sato
Ning Ma
Keiichi Hiramoto
Masahiro Terasawa
Koji Suzuki
Rhamnan Sulfate from the Seaweed <i>Monostroma nitidum</i> May Improve Cognitive Impairment Caused by Hyperglycemia
Marine Drugs
diabetic cognitive impairment
hippocampal atrophy
microglia
rhamnan sulfate
<i>Monostroma nitidum</i>
title Rhamnan Sulfate from the Seaweed <i>Monostroma nitidum</i> May Improve Cognitive Impairment Caused by Hyperglycemia
title_full Rhamnan Sulfate from the Seaweed <i>Monostroma nitidum</i> May Improve Cognitive Impairment Caused by Hyperglycemia
title_fullStr Rhamnan Sulfate from the Seaweed <i>Monostroma nitidum</i> May Improve Cognitive Impairment Caused by Hyperglycemia
title_full_unstemmed Rhamnan Sulfate from the Seaweed <i>Monostroma nitidum</i> May Improve Cognitive Impairment Caused by Hyperglycemia
title_short Rhamnan Sulfate from the Seaweed <i>Monostroma nitidum</i> May Improve Cognitive Impairment Caused by Hyperglycemia
title_sort rhamnan sulfate from the seaweed i monostroma nitidum i may improve cognitive impairment caused by hyperglycemia
topic diabetic cognitive impairment
hippocampal atrophy
microglia
rhamnan sulfate
<i>Monostroma nitidum</i>
url https://www.mdpi.com/1660-3397/23/6/250
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