Diabetes mellitus (DM) is one of the most modern chronic metabolic diseases in the world. Moreover, DM is one of the major causes of modern neurological diseases. In the present study, the therapeutic actions of Korean red ginseng were evaluated in type 1 and type 2 diabetic mouse models using auditory electrophysiological measurement. The comprehensive results from auditory brainstem response (ABR), auditory middle latency response (AMLR), and transient evoked otoacoustic emission (TEOAE) demonstrate auditory functional damage caused by type 1 or 2 DM. Korean red ginseng improved the hearing threshold shift, delayed latencies and signal intensity decrease in type 2 diabetic mice. Type 1 diabetic mice showed a partial improvement in decreasing amplitude and signal intensity, not significantly. We suggest that the Korean red ginseng has a more potent efficacy in hearing loss in insulin resistance type 2 diabetes than in type 1 diabetes.

Pancreatic islets (PIs) are damaged under diabetic conditions, resulting in decreased PI size. This study examined the regenerative effects of coffee and its components (caffeine, CFI; trigonelline, TRG; chlorogenic acid, CGA) on zebrafish larval PIs and β-cells damaged by administration of alloxan (AX). In addition, the influence of coffee and its active components on KATP channels was investigated using diazoxide (DZ) as a KATP channel activator. PI size and fluorescence intensity were significantly increased in the coffee-treated group relative to the no-treatment group (P < 0.0001). In addition, coffee exerted significant regenerative effects on pancreatic β-cells (p = 0.006). Treatment with TRG and CGA rescued PI damage, and the combination of TRG/CGA had a synergistic effect. In conclusion, the results indicate that coffee has beneficial effects on AX-damaged PIs and may also be useful as a blocker of pancreatic β-cell K(+) channels.

No abstract

The aim of this study was to evaluate the hypolipidemic effect and mechanisms of total phenylpropanoid glycosides extracted from Ligustrum robustum (Roxb.) Blume (LRTPG) in hamsters fed a high-fat diet and to discover bioactive components in HepG2 cell model induced by oleic acid. LRTPG of high (1.2 g/kg), medium (0.6 g/kg), and low (0.3 g/kg) doses was administrated daily for 21 consecutive days in hamsters. We found that in hamsters fed a high-fat diet, LRTPG effectively reduced the concentrations of plasma triglycerides (TG), free fatty acid, total cholesterol, low-density lipoprotein cholesterol, and hepatic TG and total cholesterol. And the compounds acteoside, ligupurpuroside A, ligupurpuroside C, and ligupurpuroside D significantly inhibited lipid accumulation in HepG2 cell at the concentration of 50 μmol/L. Mechanism research demonstrated that LRTPG increased the levels of phospho-AMP-activated protein kinase and phospho-sterol regulatory element binding protein-1c in liver, further to suppress the downstream lipogenic genes as stearoyl-CoA desaturase 1, glycerol-3-phosphate acyltransferase, 1-acylglycerol-3-phosphate O-acyltransferase 2, and diacylglycerol acyltransferase 2. In addition, LRTPG increased the hydrolysis of circulating TG by up-regulating lipoprotein lipase activities. These results indicate that LRTPG prevents hyperlipidemia via activation of hepatic AMP-activated protein kinase-sterol regulatory element binding protein-1c pathway.

Background20(S)-Protopanaxadiol 20-O-D-glucopyranoside, also called compound K (CK), exerts antidiabetic effects that are mediated by insulin secretion through adenosine triphosphate (ATP)-sensitive potassium (KATP) channels in pancreatic β-cells. However, the antidiabetic effects of CK may be limited because of its low bioavailability.MethodsIn this study, we aimed to enhance the antidiabetic activity and lower the toxicity of CK by including it with β-cyclodextrin (CD) (CD-CK), and to determine whether the CD-CK compound enhanced pancreatic islet recovery, compared to CK alone, in an alloxan-induced diabetic zebrafish model. Furthermore, we confirmed the toxicity of CD-CK relative to CK alone by morphological changes, mitochondrial damage, and TdT-UTP nick end labeling (TUNEL) assays, and determined the ratio between the toxic and therapeutic dose for both compounds to verify the relative safety of CK and CD-CK.ResultsThe CD-CK conjugate (EC50 = 2.158μM) enhanced the recovery of pancreatic islets, compared to CK alone (EC50 = 7.221μM), as assessed in alloxan-induced diabetic zebrafish larvae. In addition, CD-CK (LC50 = 20.68μM) was less toxic than CK alone (LC50 = 14.24μM). The therapeutic index of CK and CD-CK was 1.98 and 9.58, respectively.ConclusionThe CD-CK inclusion complex enhanced the recovery of damaged pancreatic islets in diabetic zebrafish. The CD-CK inclusion complex has potential as an effective antidiabetic efficacy with lower toxicity.