scholarly journals Glucose consumption assay discovered a novel compound from natural product with beneficial effects on diabetic mice via AMPK activation

Author(s):  
Xiuying Yang ◽  
Li-li Shi ◽  
Wei-hua Jia ◽  
Li Zhang ◽  
Chun-yang Xu ◽  
...  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Kai Fang ◽  
Ming Gu

Crocin is a carotenoid compound which possesses multiple biological activities. Our and other laboratory’s previous findings show that crocin alleviates obesity and type 2 diabetes-related complications. We have found that crocin activates AMP-activated protein kinase (AMPK) signaling and inhibition of AMPK suppresses crocin-induced protective effects. However, the causal role of AMPK activation in the biological role of crocin is still not verified. In the present study, we showed that crocin markedly inhibits the changes of glucose metabolic parameters and serum lipid profiles in wild type diabetic mice. In AMPKα KO diabetic mice, those protective effects of crocin against glucose and lipid metabolic dysfunction were abolished. These results demonstrated AMPK activation was responsible for the beneficial effects of crocin on metabolic dysfunction. Moreover, we have shown that the antiobese effect of crocin has been abolished by the deficiency of AMPKα. We also showed that crocin induced a significant decrease of CDK5 protein level in wild type diabetic mice, while this effect was abolished in AMPKα KO diabetic mice. The regulation of downstream targets of CDK5/PPARγ by crocin was abolished by the deficiency of AMPK. In conclusion, our study verified that activation of AMPK is involved in crocin-induced protective effects against glucose and lipid metabolic dysfunction. Activation of AMPK downregulates the protein level of CDK5, followed by the decrease of PPARγ phosphorylation, leading to the inhibition of adipose formation and metabolic dysfunction. Our study provides new insights into the mechanism of protective effects of crocin and interaction of AMPK and CDK5/PPARγ signaling.


2012 ◽  
Vol 90 (3) ◽  
pp. 371-378 ◽  
Author(s):  
Menakshi Bhat Dusane ◽  
Bimba N. Joshi

The present study investigates the antidiabetogenic effects of Murraya koenigii (L.) Spr. and Ocimum tenuflorum  L. on streptozotocin-induced diabetic Swiss mice. Treatment with extracts of M. koenigii (chloroform; MKC) and O. tenuflorum (aqueous; OTA) resulted in proper glucose utilization with an increase in liver glucose-6-phosphate dehydrogenase enzyme activity, and normal glycogenesis in hepatic and muscle tissues. Pancreatic and intestinal glucosidase inhibitory activity observed with MKC and OTA treatment indicated beneficial effects in reducing postprandial hyperglycemia with concomitant improvement in glucose metabolism. The glucosidase inhibition was prolonged, even after discontinuation of MKC and OTA treatment. Normalization of plasma insulin and C-peptide levels was observed in diabetic mice, indicating endogenous insulin secretion after treatment. The histochemical and immunohistochemical analysis of pancreatic islets suggests the role of MKC and OTA in pancreatic β-cell protection and the functional pancreatic islets that produce insulin. The study demonstrates the significance of MKC and OTA in glucosidase inhibition and islet protection in the murine diabetic model. These findings suggest the potential of the extracts in adjuvant therapy for the treatment of diabetes and the possible development of potential neutraceuticals.


2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Jung Hwan Oh ◽  
Fatih Karadeniz ◽  
Jung Im Lee ◽  
Youngwan Seo ◽  
Mi-Soon Jang ◽  
...  

Luteolin is a common phytochemical from the flavonoid family with a flavone structure. Studies reported several bioactivities for luteolin and similar flavones. Attenuating the increased adipogenesis of bone marrow cells (hBM-MSCs) has been regarded as a therapeutic target against osteoporotic bone disorders. In the present study, the potential roles of luteolin and its sulfonic acid derivative luteolin-OSO3Na in regulating adipogenic differentiation of hBM-MSCs were investigated. Adipo-induced cells were treated with or without compounds, and their effect on adipogenesis was evaluated by adipogenic marker levels such as lipid accumulation and PPARγ pathway activation. Luteolin hindered the adipogenic lipid accumulation in adipo-induced hBM-MSCs. Immunoblotting and reverse transcription-polymerase chain reaction analysis results indicated that luteolin downregulated PPARγ and downstream factors of C/EBPα and SREBP1c expression which resulted in inhibition of adipogenesis. Luteolin-OSO3Na showed similar effects; however, it was significantly less effective compared to luteolin. Investigating p38, JNK, and ERK MAPKs and AMPK activation indicated that luteolin suppressed the MAPK phosphorylation while stimulating AMPK phosphorylation. On the other hand, luteolin-OSO3Na was not able to notably affect the MAPK and AMPK activation. In conclusion, this study suggested that luteolin inhibited adipogenic differentiation of hBM-MSCs via upregulating AMPK activation. Replacing its 4′-hydroxyl group with sulfonic acid sodium salt diminished its antiadipogenic effect indicating its role in regulating AMPK activation. The general significance is that luteolin is a common phytochemical with various health-beneficial effects. The current study suggested that luteolin may serve as a lead compound for developing antiosteoporotic substances with antiadipogenic properties.


2018 ◽  
Vol 315 (6) ◽  
pp. E1264-E1273
Author(s):  
Ursula H. Neumann ◽  
Michelle M. Kwon ◽  
Robert K. Baker ◽  
Timothy J. Kieffer

It was long thought that the only hormone capable of reversing the catabolic consequences of diabetes was insulin. However, various studies have demonstrated that the adipocyte-derived hormone leptin can robustly lower blood glucose levels in rodent models of insulin-deficient diabetes. In addition, it has been suggested that some of the metabolic manifestations of insulin-deficient diabetes are due to hypoleptinemia as opposed to hypoinsulinemia. Because insulin therapy increases leptin levels, we sought to investigate the contribution of leptin to the beneficial effects of insulin therapy. To do this, we tested insulin therapy in streptozotocin (STZ) diabetic mice that were either on an ob/ ob background or that were given a leptin antagonist to determine if blocking leptin action would blunt the glucose-lowering effects of insulin therapy. We found that STZ diabetic ob/ ob mice have a diminished blood glucose-lowering effect in response to insulin therapy compared with STZ diabetic controls and exhibited more severe weight loss post-STZ injection. In addition, STZ diabetic mice administered a leptin antagonist through daily injection or plasmid expression respond less robustly to insulin therapy as assessed by both fasting blood glucose levels and blood glucose levels during an oral glucose tolerance test. However, leptin antagonism did not prevent the insulin-induced reduction in β-hydroxybutyrate and triglyceride levels. Therefore, we conclude that elevated leptin levels can contribute to the glucose-lowering effect of insulin therapy in insulin-deficient diabetes.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
A Young Min ◽  
Jae-Myung Yoo ◽  
Dai-Eun Sok ◽  
Mee Ree Kim

Although mulberry fruit has various beneficial effects, its effect on diabetes-related dementia remains unknown. We investigated whether the ethyl acetate fraction of ethanolic extract of mulberry fruit (MFE) could alleviate biochemical and behavioral deficits in alloxan-induced diabetic mice. In the diabetic mice, MFE considerably abolished multiple deficits, e.g., body weight reduction; water and food intake increase; and hyperglycemia, hyperlipidemia, hypoinsulinism, and hypertrophy of the liver, kidneys, spleen, and brain. A 200 mg/kg MFE dose reduced malondialdehyde levels and improved antioxidant enzyme activity in the liver, kidney, and brain tissues. MFE attenuated hyperglycemia-induced memory impairments and acetylcholine deprivation, protected neuronal cells in CA1 and CA3 regions via p-CREB/BDNF pathway activation, and reduced amyloid-β precursor protein and p-Tau expressions in the brain tissue. In conclusion, MFE exerts antidiabetic and neuroprotective effects by upregulating antioxidative activities and p-CREB/BDNF pathway in chronic diabetes. Therefore, MFE may be used as a therapeutic agent for diabetes and diabetic neurodegenerative diseases.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Kexin Wang ◽  
Feng Song ◽  
Hongxing Wang ◽  
Jun-hui Wang ◽  
Yu Sun

Diabetic patients are at increased risk for developing memory and cognitive deficit. Prior studies indicate that neuroinflammation might be one important underlying mechanism responsible for this deficit. Quetiapine (QTP) reportedly exerts a significant neuroprotective effect in animal and human studies. Here, we investigated whether QTP could prevent memory deterioration and cognitive impairment in a streptozotocin- (STZ-) induced diabetic mouse model. In this study, we found that STZ significantly compromised the behavioral performance of mice in a puzzle box test, but administering QTP effectively attenuated this behavioral deficit. Moreover, our results showed that QTP could significantly inhibit the activation of astrocytes and microglia in these diabetic mice and reduce the generation and release of two cytokines, tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1). Meanwhile, QTP also prevented the protein loss of the synaptic protein synaptophysin (SYP) and myelin basic protein (MBP). Here, our results indicate that QTP could inhibit neuroinflammatory response from glial cells and block the injury of released cytokines to neurons and oligodendrocytes in diabetic mice (DM). These beneficial effects could protect diabetic mice from the memory and cognitive deficit. QTP may be a potential treatment compound to handle the memory and cognitive dysfunction in diabetic patients.


Diabetes ◽  
2011 ◽  
Vol 60 (9) ◽  
pp. 2397-2406 ◽  
Author(s):  
T. Himeno ◽  
H. Kamiya ◽  
K. Naruse ◽  
N. Harada ◽  
N. Ozaki ◽  
...  

2009 ◽  
Vol 116 (8) ◽  
pp. 607-620 ◽  
Author(s):  
Aaron K. F. Wong ◽  
Jacqueline Howie ◽  
John R. Petrie ◽  
Chim C. Lang

AMPK (AMP-activated protein kinase) is a heterotrimetric enzyme that is expressed in many tissues, including the heart and vasculature, and plays a central role in the regulation of energy homoeostasis. It is activated in response to stresses that lead to an increase in the cellular AMP/ATP ratio caused either by inhibition of ATP production (i.e. anoxia or ischaemia) or by accelerating ATP consumption (i.e. muscle contraction or fasting). In the heart, AMPK activity increases during ischaemia and functions to sustain ATP, cardiac function and myocardial viability. There is increasing evidence that AMPK is implicated in the pathophysiology of cardiovascular and metabolic diseases. A principle mode of AMPK activation is phosphorylation by upstream kinases [e.g. LKB1 and CaMK (Ca2+/calmodulin-dependent protein kinase], which leads to direct effects on tissues and phosphorylation of various downstream kinases [e.g. eEF2 (eukaryotic elongation factor 2) kinase and p70 S6 kinase]. These upstream and downstream kinases of AMPK have fundamental roles in glucose metabolism, fatty acid oxidation, protein synthesis and tumour suppression; consequently, they have been implicated in cardiac ischaemia, arrhythmias and hypertrophy. Recent mechanistic studies have shown that AMPK has an important role in the mechanism of action of MF (metformin), TDZs (thiazolinediones) and statins. Increased understanding of the beneficial effects of AMPK activation provides the rationale for targeting AMPK in the development of new therapeutic strategies for cardiometabolic disease.


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