Hypoglycemic and hypolipidemic action of Du-zhong (Eucommia ulmoides Oliver) leaves water extract in C57BL/KsJ-db/db mice

Quality Marker Discovery and Quality Evaluation of Eucommia ulmoides Pollen Using UPLC-QTOF-MS Combined with a DPPH-HPLC Antioxidant Activity Screening Method

Pollen, as an important component of Eucommia ulmoides (EUP), is rich in nutrients and is receiving increasing attention. At present, there are no reports on research related to the chemical composition and quality standards of EUP, and there are significant quality differences and counterfeit phenomena in the market. This study used a UPLC-QTOF-MS system to identify 49 chemical components in EUP for the first time. In the second step, 2,2-diphenyl-1-picrylhydrazyl (DPPH)-HPLC antioxidant activity screening technology was used to identify the main active components of EUP, quercetin-3-O-sophoroside (QSH), quercetin-3-O-sambubioside (QSB), and quercetin 3-O-neohesperidoside (QNH), and their purification, preparation, and structure identification were carried out. Third, molecular docking was used to predict the activity of these components. Fourth, the intracellular ROS generation model of RAW264.7 induced by H₂O₂ was used to verify and evaluate the activity of candidate active ingredients to determine their feasibility as Q-markers. Finally, a quality control method for EUP was constructed using the three selected components as Q-markers. The identification of chemical components and the discovery, prediction, and confirmation of characteristic Q-markers in EUP provide important references for better research on EUP and the effective evaluation and control of its quality. This approach provides a new model for the quality control of novel foods or dietary supplements.

Quercetin-3-O-α-L-arabinopyranosyl-(1→2)-β-D-glucopyranoside Isolated from Eucommia ulmoides Leaf Relieves Insulin Resistance in HepG2 Cells via the IRS-1/PI3K/Akt/GSK-3β Pathway

For nearly 2000 years, Eucommia ulmoides Oliver (EUO) has been utilized in traditional Chinese medicine (TCM) throughout China. Flavonoids present in bark and leaves of EUO are responsible for their antioxidant, anti-inflammatory, antitumor, anti-osteoporosis, hypoglycemic, hypolipidemic, antibacterial, and antiviral properties, but the main bioactive compound has not been established yet. In this study, we isolated and identified quercetin glycoside (QAG) from EUO leaves (EUOL) and preliminarily explored its molecular mechanism in improving insulin resistance (IR). The results showed that QAG increased uptake of glucose as well as glycogen production in the palmitic acid (PA)-induced HepG2 cells in a dose-dependent way. Further, we observed that QAG increases glucose transporters 2 and 4 (GLUT2 and GLUT4) expression and suppresses the phosphorylation of insulin receptor substrate (IRS)-1 at serine⁶¹², thus promoting the expression of phosphatidylinositol-3-kinase (PI3K) at tyrosine⁴⁵⁸ and tyrosine¹⁹⁹, as well as protein kinase B (Akt) and glycogen synthase kinase (GSK)-3β at serine⁴⁷³ and serine⁹, respectively. The influence posed by QAG on the improvement of uptake of glucose was significantly inhibited by LY294002, a PI3K inhibitor. In addition, the molecular docking result showed that QAG could bind to insulin receptors. In summary, our data established that QAG improved IR as demonstrated by the increased uptake of glucose and glycogen production through a signaling pathway called IRS-1/PI3K/Akt/GSK-3β.

Eucommia bark/leaf extract improves HFD-induced lipid metabolism disorders via targeting gut microbiota to activate the Fiaf-LPL gut-liver axis and SCFAs-GPR43 gut-fat axis

BACKGROUND

The bark of Eucommia ulmoides (a perennial deciduous tree termed eucommia hereafter) has anti-hyperlipidemia effects due to its bioactive components. However, the slow growth of eucommia bark leads to a deficit in this resource. Studies have shown that eucommia leaf has bioactive components similar to those of eucommia bark and anti-hyperlipidemia effects. At present, the strength of the anti-hyperlipidemia effect of eucommia bark and eucommia leaf has not been reported. Their interaction with the gut microbiota and the mechanism by which the gut microbiota exerts anti-hyperlipidemia effects are unclear.

PURPOSES

Through fecal microbiota transplantation (FMT) experiments, this study aimed to investigate the mechanism by which fecal bacteria suspensions containing chlorogenic acid (CGA), eucommia bark extract (EBE), and eucommia leaves extract (ELE) improve high-fat diet (HFD)-induced lipid metabolism disorders. Difference in anti-hyperlipidemia effects between EBE and ELE and exploring an eucommia bark substitute to improve the sustainable utilization of eucommia were also evaluated.

RESULTS

EBE and ELE contain eight identical bioactive ingredients, and fecal bacteria suspensions containing EBE and ELE significantly improved HFD-induced lipid metabolism disorders and elevated blood glucose levels. The fecal bacteria suspension of healthy mice containing CGA, EBE, and ELE significantly reduced the relative abundance of Erysipelothrichaceae and Ruminococcaceae and promoted short chain fatty acids (SCFAs) production thereby activating the expression of the SCFA. G protein-coupled receptor 43 (GPR43) gene in colon and epididymal fat tissues. In addition, fecal bacteria suspensions of healthy mice containing CGA, EBE, or ELE significantly activated fasting-induced adipose factor (Fiaf) gene expression in colon tissue and inhibited the secretion of lipoprotein lipase (LPL) in liver tissue, thereby inhibiting the synthesis of triglycerides (TG). Changed in the Erysipelotrichaceae and Ruminococcaceae relative abundances were significantly correlated with these target genes. Thus, regulating the abundance of the Erysipelotrichaceae and Ruminococcaceae could serve as a potential target for the role of fecal bacteria suspensions of healthy mice containing CGA, EBE, or ELE in the Fiaf-LPL gut-liver axis and SCFAs-GPR43 gut-fat axis. In addition, regarding HFD-induced lipid metabolism disorders and gut microbiota structural disorders, we found no significant difference between ELE and EBE.

CONCLUSIONS

Our FMT experiments evidenced that EBE and ELE improve lipid metabolism disorders by regulating the gut microbiota, providing a new pathway for treating hyperlipidemia using eucommia dietary therapy. There was no significant difference in the anti-hyperlipidemia effects of ELE and EBE; thus, eucommia leaf could replace eucommia bark in traditional Chinese medicine, so as to achieve a sustainable utilization of eucommia resources.

Feeding Laying Ducks Eucommia ulmoides oliv. Leaves Increases the n-3 Fatty Acids Content and Decreases the n-6: n-3 PUFA Ratio in Egg Yolk without Affecting Laying Performance or Egg Quality

The objective was to determine the effects of supplementing duck diets with Eucommia ulmoides oliv. leaf powder (EUL). Laying ducks (n = 480) were randomly allocated into 4 experimental treatments and fed diets containing 0, 1, 2, or 4% EUL. Dietary inclusion of EUL had no effect (p > 0.05) on laying performance or egg quality, but linearly increased (p < 0.05) total plasma protein, globulin, and HDL-C concentrations with concurrent reductions (p < 0.05) in plasma concentrations of cholesterol and LDL-C. Eggs laid by ducks receiving EUL had yolks with linearly higher phenolic concentrations (p < 0.05) but lower cholesterol concentrations (p < 0.05). EUL supplementation in duck diets significantly reduced n-6: n-3 PUFA ratio by enriching n-3 fatty acids in yolks (p < 0.05) with no changes in n-6 PUFA (p >0.05).

A systematic analysis of anti-diabetic medicinal plants from cells to clinical trials

Background

Diabetes is one of the fastest-growing health emergencies of the 21st century, placing a severe economic burden on many countries. Current management approaches have improved diabetic care, but several limitations still exist, such as decreased efficacy, adverse effects, and the high cost of treatment, particularly for developing nations. There is, therefore, a need for more cost-effective therapies for diabetes management. The evidence-based application of phytochemicals from plants in the management of diseases is gaining traction.

Methodology

Various plants and plant parts have been investigated as antidiabetic agents. This review sought to collate and discuss published data on the cellular and molecular effects of medicinal plants and phytochemicals on insulin signaling pathways to better understand the current trend in using plant products in the management of diabetes. Furthermore, we explored available information on medicinal plants that consistently produced hypoglycemic effects from isolated cells to animal studies and clinical trials.

Results

There is substantial literature describing the effects of a range of plant extracts on insulin action and insulin signaling, revealing a depth in knowledge of molecular detail. Our exploration also reveals effective antidiabetic actions in animal studies, and clear translational potential evidenced by clinical trials.

Conclusion

We suggest that this area of research should be further exploited in the search for novel therapeutics for diabetes.

Determination of multiple pesticides in Eucommia ulmoides followed by gas chromatography mass spectrometry based on a solid-phase extraction method

Eucommia ulmoides, a precious Chinese herbal medicine, lack of studies on the detection of its pesticide residues. A simple sample preparation based on the solid-phase extraction (SPE) procedure was established for the analysis of 16 kinds of pesticides in Eucommia ulmoides by gas chromatography mass spectrometry (GC-MS) with selective ion monitoring mode. Here, the type and volume of extraction solvent and eluent, the kinds of sorbents in SPE Cleanert column, were optimized. Under the optimal conditions, a good linear relationship was obtained in the range of 0.005 to 5.0 mg/L with correlation coefficient (r) higher than 0.9990, and the average recoveries (AR) of 16 pesticides ranged from 79.6 to 109.2% at the spiking levels of 0.01, 0.1, and 0.5 mg/kg. The relative standard deviations (RSD) were 0.78 to 9.56% (n = 6). The results show that the established method can not only fully meet the analytical requirements of various pesticides in Eucommia ulmoides, but also have the potential to be applied in the detection of pesticide residues in others Chinese herbal medicine.

Effect of Ethyl Acetate Fraction from Eucommia ulmoides Leaves on PM2.5-Induced Inflammation and Cognitive Dysfunction

This study aimed to evaluate the protective effect of the ethyl acetate from Eucommia ulmoides leaves (EFEL) on PM2.5-induced cognitive impairment in BALB/c mice. EFEL improved PM2.5-induced cognitive decline by improving spontaneous alternative behavioral and long-term memory ability. EFEL increased ferric reducing activity power (FRAP) in serum. In addition, EFEL increased superoxide dismutase (SOD) and reduced glutathione (GSH) contents and inhibited the production of malondialdehyde (MDA) in lung and brain tissues. EFEL also restored the mitochondrial function by regulating reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP) level, and ATP level in lung and brain tissues. EFEL ameliorated the cholinergic system by regulating the acetylcholine (ACh) content and acetylcholinesterase (AChE) activity in the brain tissue and the expression of AChE and choline acetyltransferase (ChAT) in the whole brain and hippocampal tissues. EFEL reduced PM2.5-induced excessive expression of inflammatory protein related to the lung, whole brain, olfactory bulb, and hippocampus. Physiological compounds of EFEL were identified as 5-O-caffeolyquinic acid, rutin, quercetin, and quercetin glycosides. As a result, EFEL has anti-inflammation and anti-amnesic effect on PM2.5-induced cognitive impairment by regulating the inflammation and inhibiting the lung and brain tissue dysfunction, and its effect is considered to be due to the physiological compounds of EFEL.

Identification of a novel laccase gene EuLAC1 and its potential resistance against Botrytis cinerea

In this study, a novel laccase gene, EuLAC1, was cloned from Eucommia ulmoides Oliver (E. ulmoides). An overexpression vector harboring the EuLAC1 was constructed and introduced into the tobacco (Nicotiana tabacum cv. Xanthi). The laccase activity, resistance to Botrytis cinerea (B. cinerea) and lignin level in wild-type and transgenic plants were thereafter investigated. Interestingly, the transgenic tobacco displayed a significantly higher laccase activity and resistance to gray mold as compared to the wild-type tobacco. Additionally, the lignin contents in the leaves and stems of the transgenic tobacco were significantly higher in comparison to the wild-type tobacco. Scanning electron microscopy was used to observe the cross sections of wild-type and transgenic tobacco stems and it was noted that the cell wall near the xylem catheter of the transgenic tobacco was substantially thicker and the outline clearer than that of the wild-type. Thus, the EuLAC1 gene can significantly increase laccase activity and lignin content in tobacco, leading to an increase in the physical defenses, thereby increasing tobacco resistance to gray mold.

Metabolism of Du Zhong Formula in rats using UPLC-Q-TOF/MS

Du Zhong Formula (DZF), a traditional Chinese medicine formula derived from BeiJiQianJinYaoFang, is used to treat kidney deficiency and lumbago. In this study, ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometer (UPLC-Q-TOF/MS) technique combined with pattern recognition analysis was applied for analysis of metabolic profiles of the bioactive components of the DZF in rat biological samples. In this experiment, a total of 73 compounds, including 53 prototype components and 20 metabolites, were identified tentatively in vivo compared with blank urine, plasma, feces, and cerebrospinal fluid (CSF). The prototype ingredients in DZF include terpenoids, gingerols, phenylpropanoids, alkaloids, phenanthrenes, bibenzyls, organic acids, and other ingredients. The metabolic pathways of DZF involved reduction, demethylation, hydroxylation, desugarization, deoxygenation, glucuronidation, sulfation, and methylation. The proposed method could develop an integrated template approach to analyze screening and identification of the bioactive components in plasma, urine, feces, and CSF after oral administration of herb medicines. Additionally, this investigation might provide helpful chemical information for further pharmacology and activity mechanism of DZF.

Traditionally Used Plants in the Treatment of Diabetes Mellitus: Screening for Uptake Inhibition of Glucose and Fructose in the Caco2-Cell Model

The traditional use of plants and their preparations in the treatment of diseases as a first medication in the past centuries indicates the presence of active components for specific targets in the natural material. Many of the tested plants in this study have been traditionally used in the treatment of Diabetes mellitus type 2 and associated symptoms in different cultural areas. Additionally, hypoglycemic effects, such as a decrease in blood glucose concentration, have been demonstrated in vivo for these plants. In order to determine the mode of action, the plants were prepared as methanolic and aqueous extracts and tested for their effects on intestinal glucose and fructose absorption in Caco2 cells. The results of this screening showed significant and reproducible inhibition of glucose uptake between 40 and 80% by methanolic extracts made from the fruits of Aronia melanocarpa, Cornus officinalis, Crataegus pinnatifida, Lycium chinense, and Vaccinium myrtillus; the leaves of Brassica oleracea, Juglans regia, and Peumus boldus; and the roots of Adenophora triphylla. Furthermore, glucose uptake was inhibited between 50 and 70% by aqueous extracts made from the bark of Eucommia ulmoides and the fruit skin of Malus domestica. The methanolic extracts of Juglans regia and Peumus boldus inhibited the fructose transport between 30 and 40% in Caco2 cells as well. These findings can be considered as fundamental work for further research regarding the treatment of obesity-correlated diseases, such as Diabetes mellitus type 2.

Traditional application and modern pharmacological research of Eucommia ulmoides Oliv

As a Traditional Chinese Medicine, Eucommia ulmoides Oliv. has been used for the treatment of various diseases since ancient times, involving lumbar pain, knee pain, osteoporosis, hepatoprotection, paralysis, intestinal haemorrhoids, vaginal bleeding, abortion, spermatorrhoea, foot fungus, anti-aging etc. With the developing discovery of E. ulmoides extracts and its active components in various pharmacological activities, E. ulmoides has gained more and more attention. Up to now, E. ulmoides has been revealed to show remarkable therapeutic effects on hypertension, hyperglycemia, diabetes, obesity, osteoporosis, Parkinson's disease, Alzheimer's disease, sexual dysfunction. E. ulmoides has also been reported to possess antioxidant, anti-inflammatory, neuroprotective, anti-fatigue, anti-aging, anti-cancer and immunoregulation activities etc. Along these lines, this review summarizes the traditional application and modern pharmacological research of E. ulmoides, providing novel insights of E. ulmoides in the treatment of various diseases.

Isoeucommin A attenuates kidney injury in diabetic nephropathy through the Nrf2/HO-1 pathway

Diabetic nephropathy (DN) is a common complication in patients with diabetes and a leading cause of mortality. The management of DN in the clinic still remains a challenge. Therefore, the identification of novel compounds for DN treatment and their characterization in preclinical DN models are crucial. Isoeucommin A is a lignan compound isolated from Eucommia ulmoides Oliv, which has not been studied in detail. Our aim was to investigate the effect of Isoeucommin A in DN and to elucidate the molecular mechanisms though which Isoeucommin A acts in vitro and in vivo. We first isolated and purified Isoeucommin A by microporous resin column chromatography and studied the mass spectrogram, as well as the structure of Isoeucommin A, by high‐resolution electrospray ionization mass spectroscopy and NMR, respectively. We further established an in vivo rat DN model and measured the changes of blood glucose, body weight, kidney index (KI), blood urea nitrogen, creatinine (CRE), glutathione, malondialdehyde (MDA), SOD, albumin (ALB) and urinary ALB to CRE ratios on treatment with Isoeucommin A. In addition, we measured SOD, MDA, glycogen synthase kinase‐3β (GSK‐3β), phosphorylated (p)‐GSK‐3β, nuclear factor erythroid‐derived 2‐related factor 2 (Nrf2) and heme oxygenase‐1 (HO‐1) levels by quantitative real‐time PCR and western blot, and estimated cell viability by a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazolium bromide assay. After Isoeucommin A treatment, body weight, as well as SOD, glutathione, HO‐1 and Nrf2 expression levels, in DN rats increased in a dose‐dependent manner. In contrast, the levels of blood glucose, KI, blood urea nitrogen, CRE, urinary ALB to CRE ratio, tumor necrosis factor‐α, interleukin‐1β, interleukin‐6 and MDA decreased significantly. In addition, Isoeucommin A protected H₂O₂‐stimulated renal tubular epithelial cells from oxidative stress and activated the Nrf2/HO‐1 signaling pathway in high‐glucose‐stimulated human renal mesangial cells. In conclusion, Isoeucommin A could alleviate inflammation and oxidative stress in in vitro and in vivo DN models and thus attenuate kidney injury by activating the Nrf2/HO‐1 signaling pathway. Isoeucommin A could have the potential to be used as an effective drug for the treatment of DN.

Pinoresinol diglucoside (PDG) attenuates cardiac hypertrophy via AKT/mTOR/NF-κB signaling in pressure overload-induced rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pinoresinol diglucoside (PDG), the active compound extracted from Eucommia ulmoides, Styrax sp. and Forsythia suspensa, plays the roles in regulating hypertension, inflammation and oxidative stress.

AIMS

Considering that hypertension and inflammation has been proved to contribute to cardiac remodeling, we tested the effects of PDG on cardiac hypertrophy (CM).

METHODS

Male Sprague Dawley (SD) rats were used to construct hypertrophic rats by partial abdominal aortic constriction (AAC)-surgery. PDG solution (2 mg/ml) was used to treat AAC-induced rats by intraperitoneal injection at low dose (L-PDG, 2.5 mg/kg per day), medium dose (M-PDG, 5 mg/kg per day), and high dose (H-PDG, 7.5 mg/kg per day) for 3 weeks post AAC-surgery. CM was evaluated by the ratio of left ventricular weight to body weight ratio (LVW/BW), left ventricular wall thickness by H&E staining, and collagen content deposit by Masson's staining. Further, isoproterenol (ISO) and phenylephrine (PE) were used to produce cellular models of CM in neonatal rat ventricular cardiomyocytes (NRVMs). PDG pre-treated NRVMs 2 h at low dose (L-PDG, 2.5 μg/ml), medium dose (M-PDG, 5 μg/ml), and high dose (H-PDG, 7.5 μg/ml) for 24 h with or without PE- and ISO-stimulation. CM was evaluated by the expressions of hypertrophic biomarkers. Next, the hypertrophic biomarkers and pro-inflammatory cytokines were measured using quantitative real-time PCR (qRT-PCR), the expressions of protein kinase B (AKT)/mammalian target of rapamycin (mTOR)/transcription factor nuclear factor-kappa B (NF-kB) signaling pathway were determined by Western blotting.

RESULTS

PDG treatment prevented cardiac histomorphology damages, decreased upregulations of hypertrophic biomarkers, and prevented fibrosis and inflammation after pressure overload resulting from AAC-surgery. Consistently, PDG remarkably inhibited the changes of cardiomyocyte hypertrophic biomarkers and inflammatory responses in cellular models of CM. Interestingly, PDG administration inhibited the activation of AKT/mTOR/NF-kB signaling pathway both in vivo and in vitro.

CONCLUSIONS

PDG prevents AAC-induced CM in vivo, PE- and ISO-induced CM in vitro. The AKT/mTOR/NF-kB signaling pathway could be the potential therapeutic target involved in the protection of PDG. These findings provide novel evidence that PDG might be a promising therapeutic strategy for CM.

Adsorption and desorption characteristics of polyphenols from Eucommia ulmoides Oliv. leaves with macroporous resin and its inhibitory effect on α-amylase and α-glucosidase

Background

Eucommia ulmoides Oliv. (EUO) was a traditional Chinese herb, its leaves were abundant in China, and polyphenol compounds were considered to be an important active ingredient in Eucommia ulmoides Oliv. leaves (EUOL). However, previous research mainly focused on compound identification and extraction process, there were few reported on the efficient enrichment process and biological activity evaluation of polyphenols in EUOL.

Methods

The adsorption and desorption characteristics of twelve different resins (HPD-100, HPD-300, HPD-600, D-3250, X-5, D-140, NKA-9, NKA-II, D-101, AB-8, S-8 and Polyamide) were investigated to develop an efficient method for the enrichment of polyphenol from EUOL, and the static adsorption, kinetics, isotherm and thermodynamics of the polyphenol from EUOL were analyzed. The eluted component was obtained through dynamic elution, and its main polyphenol compounds were detected by high-phase liquid chromatography (HPLC) and the inhibitory effects on the enzyme activity of α-amylase and α-glucosidase was also evaluated for different elution components. Meanwhile, the binding of main polyphenol compounds to enzyme was also evaluated.

Results

The selected resins (HPD-300, HPD-600, D-3250, X-5, D-140, NKA-9, D-101 and AB-8) showed adsorption patterns that fitted well to the pseudo second-order kinetics. The intra-particle diffusion model demonstrated that the diffusion of polyphenol compounds on these resins were divided into three processes. For HPD-300, HPD-600 and NKA-9, the Freundlich model better described the adsorption isotherm behavior than the Langmuir model, and the adsorption of polyphenol was a physical, exothermic, and spontaneous process. Subsequently, dynamic elution was performed yielding a higher polyphenol content in a 60% ethanol-water elution component, and it also exhibited a higher inhibitory effect on α-amylase and α-glucosidase activity. Furthermore, as the main polyphenol compounds, chlorogenic acid, rutin, quercetin and kaempferol were used to simulate the binding to the enzyme protein through molecular docking technology. The results showed that quercetin had a higher docking score for α-amylase, while rutin displayed superior binding to α-glucosidase.

Conclusions

Therefore, polyphenols of EUOL could be enriched through macroporous resins and have the potential to be effective enzyme inhibitor.

Eucommia ulmoides Oliv. Leaf Extract Improves Erectile Dysfunction in Streptozotocin-Induced Diabetic Rats by Protecting Endothelial Function and Ameliorating Hypothalamic-Pituitary-Gonadal Axis Function

Erectile dysfunction (ED) is a major complication of diabetes mellitus. Eucommia ulmoides Oliv. is used as a traditional medicine for male impotence, but no systematic study has examined its effect on diabetes-associated ED. In this study, we investigated the effects of Eucommia ulmoides Oliv. leaf extract (EULE) on restoring erectile function in streptozotocin (STZ)-induced diabetic rats model. After 16 weeks of treatment, EULE administration had significantly increased intracavernosal pressure, nitric oxide (NO) levels, and cyclic guanosine monophosphate (cGMP) concentrations. Serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels were markedly higher and serum malondialdehyde (MDA) levels were lower in the EULE-treated groups than in the diabetic model group. EULE restored NO biosynthesis by significantly increasing protein kinase B (Akt) and endothelial NO synthase (eNOS) activation. Furthermore, EULE is likely to benefit the hypothalamic-pituitary-gonadal (HPG) axis, as it increased gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) concentrations as well as hormone receptors Gnrhr, Fshr, and Lhr expression levels. Hence, EULE attenuates oxidative stress, increases NO production, and activates the Akt-eNOS pathway to restore endothelial function; moreover, EULE enhances the HPG axis to improve erectile function. These results suggest that EULE may represent a new therapeutic avenue for diabetes-associated ED.

Ethnobotany, Phytochemistry and Pharmacological Properties of Eucommia ulmoides: A Review

Eucommia ulmoides Oliver, a single species of Eucommia genus belonging to the Eucommiaceae family, is an endemic in China and has been used in traditional Chinese medicine for nearly two thousand years. Records from different historical periods highlight E. ulmoides and its officinal botanical parts, usefulness in adaptation to disease and its central role in Chinese medicine theory. There are also historical collection documents for minorities in China. Tearing the leaves, bark and fruit produces strands of latex; a description of E. ulmoides’s morphological features is recorded in this paper. This review summarizes 204 natural compounds isolated from this plant, which are divided into seven categories: lignans, iridoids, flavonoids, phenols, steroids, terpenes and others. These components possess wide-ranging pharmacological efficacies, such as antihypertensive, antihyperglycemic, antihyperlipidemia, anti-oxidative, anti-osteoporosis, antitumor, immunomodulatory and neuroprotective activities. This review aims to provide a reference for extensive researches of E. ulmoides crude drugs, especially for quality control, biosynthesis and structure modification of active ingredients and pharmacological mechanism.

R. verniciflua and E. ulmoides Extract (ILF-RE) Protects against Chronic CCl₄-Induced Liver Damage by Enhancing Antioxidation

This study aimed to characterize the protective effects of R. verniciflua extract (ILF-R) and E. ulmoides extract (ILF-E), the combination called ILF-RE, against chronic CCl₄-induced liver oxidative injury in rats, as well as to investigate the mechanism underlying hepatoprotection by ILF-RE against CCl₄-induced hepatic dysfunction. Chronic hepatic stress was induced via intraperitoneal (IP) administration of a mixture of CCl₄ (0.2 mL/100 g body weight) and olive oil [1:1(v/v)] twice a week for 4 weeks to rats. ILF-RE was administered orally at 40, 80, and 120 mg/kg to rats for 4 weeks. Alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transpeptidase (GGT), and lipid peroxidation assays were performed, and total triglyceride, cholesterol, and LDL-cholesterol levels were quantified. Furthermore, ER stress and lipogenesis-related gene expression including sterol regulatory element-binding transcription factor 1 (SREBP-1), fatty acid synthase (FAS), and P-AMPK were assessed. ILF-RE markedly protected against liver damage by inhibiting oxidative stress and increasing antioxidant enzyme activity including glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase. Furthermore, hepatic dyslipidemia was regulated after ILF-RE administration. Moreover, hepatic lipid accumulation and its associated lipogenic genes, including those encoding SREBP-1 and FAS, were regulated after ILF-RE administration. This was accompanied by regulation of ER stress response signaling, suggesting a mechanism underlying ILF-RE-mediated hepatoprotection against lipid accumulation. The present results indicate that ILF-RE exerts hepatoprotective effects against chronic CCl₄-induced dysfunction by suppressing hepatic oxidative stress and lipogenesis, suggesting that ILF-RE is a potential preventive/therapeutic natural product in treating hepatoxicity and associated dysfunction.

Traditional Chinese medicine suppresses left ventricular hypertrophy by targeting extracellular signal-regulated kinases signaling pathway in spontaneously hypertensive rats

Chinese herbal medicine Bu-Shen-Jiang-Ya decoction (BSJYD) is reported to be beneficial for hypertension. Over expression of extracellular signal regulated kinases (ERK) pathway plays an important role in left ventricular hypertrophy (LVH). This study aimed to observe effects of BSJYD on LVH in spontaneously hypertensive rats (SHRs) and explore its possible mechanism on regulation of ERK pathway. Sixty 12-week-old SHRs were randomly allocated into 5 groups: BSJYD high dose group, middle dose group, low dose group, captopril group, and control group. Besides, a control group of Wistar-Kyoto rats was established. All rats were treated for 8 weeks. Systolic blood pressure (SBP), heart rate (HR), pathology, and left ventricular mass index (LVMI) were measured. Western blotting and Real-time PCR were used to assess the expressions of BDNF, Ras, ERK1/2, and c-fox levels. SBP and HR were significantly decreased compared with the control group and LVMI was markedly improved by BSJYD treatment in a dose-dependent manner. BSJYD inhibited the expression of BDNF, Ras, ERK1/2, and c-fox mRNA in LVH. In conclusion, BSJYD suppressed hypertension-induced cardiac hypertrophy by inhibiting the expression of ERK pathway. These changes in gene expression may be a possible mechanism by which BSJYD provides myocardial protection from hypertension.

Pinoresinol Diglucoside Alleviates oxLDL-Induced Dysfunction in Human Umbilical Vein Endothelial Cells

Atherosclerotic cardiovascular diseases are the leading causes of morbidity and mortality worldwide. Deposition of oxidized low-density lipoprotein (oxLDL) is one of the initiators and promoters of atherosclerosis. Eucommia lignans were shown to possess antihypertensive effects. This study aimed to investigate the effects of pinoresinol diglucoside (PD), a Eucommia lignan, on oxLDL-induced endothelial dysfunction. HUVECs were treated with oxLDL and/or PD followed by assessing radical oxygen species (ROS), apoptosis, nitrogen oxide (NO), malondialdehyde (MDA), and superoxide dismutase (SOD) activity with specific assays kits, mRNA levels with quantitative real-time polymerase chain reaction (PCR), and protein levels with western blot. PD abolished oxLDL-induced ROS and MDA production, apoptosis, upregulation of lectin-like oxidized LDL recptor-1 (LOX-1), intercellular Adhesion Molecule 1 (ICAM-1), and nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB), and activation of p38MAPK (mitogen-activated protein kinases)/NF-κB signaling. Meanwhile, PD alleviated oxLDL-caused inhibition of SOD activity, eNOS expression, and NO production. These data demonstrated that PD was effective in protecting endothelial cells from oxLDL-caused injuries, which guarantees further investigation on the clinical benefits of PD on cardiovascular diseases.

Sargassum coreanum extract alleviates hyperglycemia and improves insulin resistance in db/db diabetic mice

BACKGROUND/OBJECTIVES

The goal of this study was to examine the effect of Sargassum coreanum extract (SCE) on blood glucose concentration and insulin resistance in C57BL-KsJ-db/db mice.

MATERIALS/METHODS

For 6 weeks, male C57BL/KsJ-db/db mice were administrated SCE (0.5%, w/w), and rosiglitazone (0.005%, w/w).

RESULTS

A supplement of the SCE for 6 weeks induced a significant reduction in blood glucose and glycosylated hemoglobin concentrations, and it improved hyperinsulinemia compared to the diabetic control db/db mice. The glucokinase activity in the hepatic glucose metabolism increased in the SCE-supplemented db/db mice, while phosphoenolpyruvate carboxykinase and glucose-6-phosphatase activities in the SCE-supplemented db/db mice were significantly lower than those in the diabetic control db/db mice. The homeostatic index of insulin resistance was lower in the SCE-supplemented db/db mice than in the diabetic control db/db mice.

CONCLUSIONS

These results suggest that a supplement of the SCE lowers the blood glucose concentration by altering the hepatic glucose metabolic enzyme activities and improves insulin resistance.

Coniferyl aldehyde attenuates radiation enteropathy by inhibiting cell death and promoting endothelial cell function

Radiation enteropathy is a common complication in cancer patients. The aim of this study was to investigate whether radiation-induced intestinal injury could be alleviated by coniferyl aldehyde (CA), an HSF1-inducing agent that increases cellular HSP70 expression. We systemically administered CA to mice with radiation enteropathy following abdominal irradiation (IR) to demonstrate the protective effects of CA against radiation-induced gastrointestinal injury. CA clearly alleviated acute radiation-induced intestinal damage, as reflected by the histopathological data and it also attenuated sub-acute enteritis. CA prevented intestinal crypt cell death and protected the microvasculature in the lamina propria during the acute and sub-acute phases of damage. CA induced HSF1 and HSP70 expression in both intestinal epithelial cells and endothelial cells in vitro. Additionally, CA protected against not only the apoptotic cell death of both endothelial and epithelial cells but also the loss of endothelial cell function following IR, indicating that CA has beneficial effects on the intestine. Our results provide novel insight into the effects of CA and suggest its role as a therapeutic candidate for radiation-induced enteropathy due to its ability to promote rapid re-proliferation of the intestinal epithelium by the synergic effects of the inhibition of cell death and the promotion of endothelial cell function.

Chlorogenic acid-enriched extract from Eucommia ulmoides leaves inhibits hepatic lipid accumulation through regulation of cholesterol metabolism in HepG2 cells

CONTEXT

Eucommia ulmoides Oliver (Eucommiaceae) leaf exhibits beneficial lipid-lowering and anti-obesity effects. However, the mechanisms remain unknown.

OBJECTIVE

The objective of this study is to investigate the lipid-lowering effects of chlorogenic acid (CGA)-enriched extract from this plant (CAEF) in human hepatoma HepG2 cells, focusing on cholesterol metabolism.

MATERIALS AND METHODS

HepG2 cells were treated with CAEF (10, 20, 25, 40, 60, and 80 mg/L), CGA (0.3, 3, 30, 300, and 600 μmol/L), and simvastatin (0.1, 1, 10, 50, and 100 μmol/L) for 24 or 48 h. The cytotoxicity, Oil red O staining, total cholesterol, and triacylglycerol in supernatants were determined. The mRNA expression of genes involved in cholesterol metabolism was determined with RT-PCR. The protein expression of HMG-CoA reductase (HMGCR) was examined by immunocytochemistry and western-blot.

RESULTS

The IC50 values were 59.2 mg/L for CAEF, 335.9 μmol/L for CGA, and 10.5 μmol/L for simvastatin. By treating cells with CAEF (25 mg/L), CGA (30 μmol/L), or simvastatin (10 μmol/L) for 48 h, the efflux of total cholesterol and triacylglycerol was increased (CAEF, 4.06- and 31.00-folds; CGA, 2.94- and 2.17-folds; and simvastatin, 3.94- and 24.67-folds), and the cellular lipid droplets were reduced in Oil red O staining. CAEF and CGA increased mRNA expression of ABCA1, CYP7A1, and AMPKα2, while CAEF and simvastatin decreased SREBP2. However, their effects on LXRα mRNA expression were variable. Importantly, all drugs significantly inhibited protein expression of HMGCR at mRNA and protein levels.

DISCUSSION AND CONCLUSION

CAEF is a promising dietary supplement to prevent obesity and dyslipidemia and the effects appear to be due, at least in part, to regulating cholesterol metabolism through inhibition of HMGCR in HepG2 cells.

Ancient records and modern research on the mechanisms of chinese herbal medicines in the treatment of diabetes mellitus

Over the past decades, Chinese herbal medicines (CHM) have been extensively and intensively studied through from both clinical and experimental perspectives and CHM have been proved to be effective in the treatment of diabetes mellitus (DM). This study, by searching ancient records and modern research papers, reviewed CHM in terms of their clinical application and principal mechanism in the treatment of DM. We summarized the use of CHM mentioned in 54 famous ancient materia medica monographs and searched papers on the hypoglycemic effect of several representative CHM. Main mechanisms and limitations of CHM and further research direction for DM were discussed. On the basis of the study, we were led to conclude that TCM, as a main form of complementary and alternative medicine (CAM), was well recorded in ancient literatures and has less adverse effects as shown by modern studies. The mechanisms of CHM treatment of DM are complex, multilink, and multitarget, so we should find main hypoglycemic mechanism through doing research on CHM monomer active constituents. Many CHM monomer constituents possess noteworthy hypoglycemic effects. Therefore, developing a novel natural product for DM and its complications is of much significance. It is strongly significant to pay close attention to CHM for treatment of DM and its complications.

Effect of Yeonryeonggobon-dan (YRGBD), an herbal complex, on glycemic control in patients with Type 2 diabetes mellitus: a case series

INTRODUCTION

Diabetes mellitus has significant effects on the human body. Recently, herbal medicines have received attention as complementary anti-diabetic agents on the basis of the results of several experimental studies. We present a series of 38 cases that demonstrate the positive effect of Yeonryeonggobon-dan (YRGBD), an herbal complex, in lowering blood sugar levels in patients with uncontrolled type 2 diabetes mellitus.

METHODS

We reviewed the medical records of 38 patients treated with YRGBD. The types and doses of other hypoglycemic agents administered to the patients remained unchanged during treatment with YRGBD.

RESULTS

After YRGBD therapy, the glycated haemoglobin level decreased from 76.16±19.90mmol/mol (9.11±1.82%) to 51.21±8.82mmol/mol (6.84±0.81%). There was a statistically significant difference between the glycated haemoglobin levels measured before and after treatment (paired t test, p<0.001).

DISCUSSION

In the present study, we show the clinical effects of YRGBD on blood sugar control in patients with type 2 diabetes mellitus. Further clinical studies investigating the effects of YRGBD are needed.

Du-zhong (Eucommia ulmoides) prevents disuse-induced osteoporosis in hind limb suspension rats

Du-Zhong has a long history of being used in traditional Chinese formulas to treat bone related diseases. The objective of the present study is to systematically investigate the effects of Du-Zhong cortex extract (DZCE) on disuse-induced osteoporosis. Rats were randomly divided into four groups, and three groups were treated with hind limb suspension (HLS). Control and HLS group received deionized distilled water, while the other two groups received alendronate (2.0 mg/kg/day) and DZCE (300 mg/kg/day) respectively by intragastric gavage for six weeks (two weeks prior to and during the four weeks of HLS). Dual-energy X-ray absorptiometry, assay of biochemical markers, and three-point bending test were employed to determine the effect of various treatments on bone mass, turnover, and strength. The trabecular bone microarchitecture was assessed by microCT analysis. DZCE could effectively prevent the bone loss induced by HLS, which was indicated by decreased levels of bone turnover markers as well as the changes in urinary calcium and phosphorus. The DZCE treatment also enhanced the biomechanical strength of bone and prevented the deterioration of trabecular bone microarchitecture. DZCE administration was able to prevent disuse-induced osteoporosis by regulating the bone metabolism, suggesting that DZCE could be used as an alternative therapy for the prevention of disuse-induced osteoporosis.

Enzogenol improves diabetes-related metabolic change in C57BL/KsJ-db/db mice, a model of type 2 diabetes mellitus

Objectives

Dietary use of pine bark extract has been associated with reduced risk of inflammation and diabetes. In this study, we investigated the antidiabetic effects of enzogenol, proanthocyanidins-rich bioflavonoid extract derived from the pine bark of New Zealand Pinus radiata trees, using C57BL/KsJ-db/db mice.

Methods

After 1-week acclimation period, the db/db mice were divided into vehicle-treated, Enzogenol-treated (12.5, 25 and 50 mg/kg; EZ) and positive control (tea polyphenol 50 mg/kg; TPP) groups.

Key findings

The administration of EZ improved the glucose tolerance and lowered the glycosylated haemoglobin (HbA1C), insulin and glucagon levels in blood. Interestingly, EZ and TPP treatments resulted in reduced hepatic free fatty acid, cholesterol and triglyceride levels in db/db mice. EZ and TPP treatments significantly elevated hepatic AMPK activity, and the expression of proteins related to glucose homeostasis and lipid metabolism, such as glucokinase, peroxisome proliferator-activated receptor (PPAR)α and long-chain acyl-CoA dehydrogenase protein level with a simultaneous reduction of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase protein expression. In addition, the EZ administration groups had an increased hepatic glycogen synthase expression in db/db mice.

Conclusions

These results suggest that EZ may be beneficial in improving insulin resistance and hyperglycaemia in type 2 diabetic mice by enhancing the glucose and lipids metabolism.

Eucommia ulmoides cortex, geniposide and aucubin regulate lipotoxicity through the inhibition of lysosomal BAX

In this study we examined the inhibition of hepatic dyslipidemia by Eucommia ulmoides extract (EUE). Using a screening assay for BAX inhibition we determined that EUE regulates BAX-induced cell death. Among various cell death stimuli tested EUE regulated palmitate-induced cell death, which involves lysosomal BAX translocation. EUE rescued palmitate-induced inhibition of lysosomal V-ATPase, α-galactosidase, α-mannosidase, and acid phosphatase, and this effect was reversed by bafilomycin, a lysosomal V-ATPase inhibitor. The active components of EUE, aucubin and geniposide, showed similar inhibition of palmitate-induced cell death to that of EUE through enhancement of lysosome activity. Consistent with these in vitro findings, EUE inhibited the dyslipidemic condition in a high-fat diet animal model by regulating the lysosomal localization of BAX. This study demonstrates that EUE regulates lipotoxicity through a novel mechanism of enhanced lysosomal activity leading to the regulation of lysosomal BAX activation and cell death. Our findings further indicate that geniposide and aucubin, active components of EUE, may be therapeutic candidates for non-alcoholic fatty liver disease.

Eucommia ulmoides Oliv.: ethnopharmacology, phytochemistry and pharmacology of an important traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Eucommia ulmoides Oliv. (Family Eucommiaceae), also known as Dù-zhòng (Chinese: ), Tuchong (in Japanese), is the sole species of the genus Eucommia. The leaf, stem, and bark as well as staminate flower of Eucommia ulmoides have been traditionally used to cure many diseases in China, Japan, Korea, among others. The aim of this review is to comprehensively outline the botanical description, ethnopharmacology, phytochemistry, biological activities, and toxicology of Eucommia ulmoides and to discuss possible trends for further study of Eucommia ulmoides.

MATERIALS AND METHODS

Information on Eucommia ulmoides was gathered via the internet (using Pub Med, Elsevier, Baidu Scholar, Google Scholar, Medline Plus, ACS, CNKI, and Web of Science) and from books in local libraries.

RESULTS

One-hundred twelve compounds of Eucommia ulmoides, including the main active constituents, lignans and iridoids, have been isolated and identified. In vitro and in vivo studies indicated that monomer compounds and extracts from Eucommia ulmoides possess wide-ranging pharmacological actions, especially in treating hypertension, hyperlipemia, diabetes, obesity, sexual dysfunction, osteoporosis, Alzheimer's disease, aging, lupus-like syndrome, and immunoregulation.

CONCLUSIONS

Eucommia ulmoides has been used as a source of traditional medicine and as a beneficial health food. Phytochemical and pharmacological studies of Eucommia ulmoides have received much interest, and extracts and active compounds continue to be isolated and proven to exert various effects. Further toxicity and clinical studies are warranted to establish more detailed data on crude extracts and pure compounds, enabling more convenient preparations for patients. Therefore, this review on the ethnopharmacology, phytochemistry, biological activities, and toxicity of Eucommia ulmoides will provide helpful data for further studies as well as the commercial exploitation of this traditional medicine.

Mechanism of the Inhibitory Effects of Eucommia ulmoides Oliv. Cortex Extracts (EUCE) in the CCl 4 -Induced Acute Liver Lipid Accumulation in Rats

Eucommia ulmoides Oliv. (EU) has been used for treatment of liver diseases. The protective effects of Eucommia Ulmoides Oliv. cortex extracts (EUCE) on the carbon tetrachloride- (CCl4-) induced hepatic lipid accumulation were examined in this study. Rats were orally treated with EUCE in different doses prior to an intraperitoneal injection of 1 mg/kg CCl4. Acute injection of CCl4 decreased plasma triglyceride but increased hepatic triglyceride and cholesterol as compared to control rats. On the other hand, the pretreatment with EUCE diminished these effects at a dose-dependent manner. CCl4 treatment decreased glutathione (GSH) and increased malondialdehyde (MDA) accompanied by activated P450 2E1. The pretreatment with EUCE significantly improved these deleterious effects of CCl4. CCl4 treatment increased P450 2E1 activation and ApoB accumulation. Pretreatment with EUCE reversed these effects. ER stress response was significantly increased by CCl4, which was inhibited by EUCE. One of the possible ER stress regulatory mechanisms, lysosomal activity, was examined. CCl4 reduced lysosomal enzymes that were reversed with the EUCE. The results indicate that oral pretreatment with EUCE may protect liver against CCl4-induced hepatic lipid accumulation. ER stress and its related ROS regulation are suggested as a possible mechanism in the antidyslipidemic effect of EUCE.

Du-zhong (Eucommia ulmoidesOliver) Leaf Extract Mediates Hypolipidemic Action in Hamsters Fed a High-Fat Diet

This study examined the effect of a Du-zhong (Eucommia ulmoides Oliver) leaf extract (0.175 g/100 g diet) that was supplemented with a high-fat diet (10% coconut oil, 0.2% cholesterol, wt/wt) on hyperlipidemic hamsters. Hamsters fed with Du-zhong leaf extract for 10 weeks showed a smaller size of epididymal adipocytes compared to the control group. The supplementation of the Du-zhong leaf extract significantly lowered the plasma levels of triglyceride, total cholesterol, LDL-cholesterol, non HDL-cholesterol, and free fatty acid, whereas it elevated the HDL-cholesterol/total cholesterol ratio and apolipoprotein A-I levels. The hepatic cholesterol concentration was lower in the Du-zhong group than in the control group. The plasma total cholesterol concentration was positively correlated with hepatic HMG- CoA reductase activity (r = 0.547, p < 0.05) and hepatic cholesterol concentration (r = 0.769, p < 0.001). The hepatic fatty acid synthase and HMG- CoA reductase activities were significantly lowered by a Du-zhong leaf extract supplement in high fat-fed hamsters. Hepatic fatty acid synthase activity was positively correlated with plasma fatty acid concentration (r = 0.513, p < 0.05) that was lower in the Du-zhong group. These results demonstrate that the Du-zhong leaf extract exhibits antihyperlipidemic properties by suppressing hepatic fatty acid and cholesterol biosynthesis with the simultaneous reduction of plasma and hepatic lipids in high fat-fed hamsters.

Effects of brown alga, Ecklonia cava on glucose and lipid metabolism in C57BL/KsJ-db/db mice, a model of type 2 diabetes mellitus

Recently, there has been a growing interest in alternative therapies of marine algae for diabetes. Therefore, the anti-diabetic effects of brown alga, Ecklonia cava was investigated in type 2 diabetic animal. Male C57BL/KsJ-db/db (db/db) mice were divided into control, dieckol rich extract of E. cava (AG-dieckol), or rosiglitazone (RG) groups. The blood glucose, blood glycosylated hemoglobin levels, and plasma insulin levels were significantly lower in the AG-dieckol and RG groups than in the control db/db mice group, while glucose tolerance was significantly improved in the AG-dieckol group. AG-dieckol markedly lowered plasma and hepatic lipids concentration compared to the control db/db mice group. The antioxidant enzyme activities were significantly higher in the AG-dieckol group than in the control db/db mice group, yet its TBARS level was markedly lower compared to the RG group. With regard to hepatic glucose regulating enzyme activities, glucokinase activity was enhanced in the AG-dieckol group mice, while glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities in the AG-dieckol group mice were significantly lowered than those in the control db/db mice group. These results suggest that AG-dieckol exert an anti-diabetic effect in type 2 diabetic mice by improving the glucose and lipid metabolism and antioxidant enzymes.

Facilitative effects of Eucommia ulmoides on fatty acid oxidation in hypertriglyceridaemic rats

BACKGROUND

Tea made from Eucommia ulmoides leaves is widely consumed as a health food, since recent studies have revealed various pharmacological effects of the tea, e.g. a hypotriglyceridaemic effect. This study was conducted to elucidate the mechanisms underlying the plasma triglyceride-lowering effect of E. ulmoides leaves.

RESULTS

Rats were divided into four groups: a normal group, a group fed a high-fat/high-fructose diet (untreated group) and two groups fed a high-fat/high-fructose diet and E. ulmoides tea (4 or 20 g L(-1) extract, treated groups). Plasma triglyceride concentrations were reduced in treated groups in a dose-dependent manner compared with the untreated group. DNA microarray analysis revealed that genes involved in hepatic α-, β- and ω-oxidation, mainly related to the peroxisome proliferator-activated receptor α and δ signalling pathway, were up-regulated in the treated group. High-performance liquid chromatography analysis showed that E. ulmoides leaves contain three phytochemicals that make up 60 mg g(-1) of the material and are likely to be the active components.

CONCLUSION

This study indicates that the promotion of fatty acid oxidation, probably by the action of phytochemicals, participates in the ameliorative effect of E. ulmoides leaves on hypertriglyceridaemia. These findings provide the scientific evidence for the functionality of E. ulmoides.

HDL cholesterol as a diagnostic tool for clinical differentiation of GCK-MODY from HNF1A-MODY and type 1 diabetes in children and young adults

INTRODUCTION

Confirmation of monogenic diabetes caused by glucokinase mutations (GCK-MODY) allows pharmacogenetic intervention in the form of insulin discontinuation. This is especially important among paediatric and young adult populations where GCK-MODY is most prevalent.

METHODS

The study evaluated the utility of lipid parameters in screening for patients with GCK-MODY. Eighty-nine children with type 1 diabetes and 68 with GCK-MODY were screened for triglyceride (TG), total and HDL cholesterol levels. Standardization against a control group of 171 healthy children was applied to eliminate the effect of development. Clinical applicability and cut-off value were evaluated in all available patients with GCK-MODY (n = 148), hepatocyte nuclear factor 1-alpha-MODY (HNF1A MODY) (n = 37) or type 1 diabetes (n = 221).

RESULTS

Lower lipid parameter values were observed in GCK-MODY than in patients with type 1 diabetes. Standard deviation scores were -0·22 ± 2·24 vs 1·31 ± 2·17 for HDL cholesterol (P < 0·001), -0·16 ± 2·14 vs 0·60 ± 1·77 for total cholesterol (P = 0·03) and -0·57 ± 0·97 vs-0·22 ± 0·97 for TG (P = 0·05). Validation analysis confirmed that HDL cholesterol was the best parameter for GCK-MODY selection [sensitivity 87%, specificity 54%, negative predictive value (NPV) 86%, positive PV 56%]. A threshold HDL concentration of 1·56 mm offered significantly better diagnostic efficiency than total cholesterol (cut-off value 4·51 mm; NPV 80%; PPV 38%; P < 0·001). TG did not offer a meaningful cut-off value.

CONCLUSIONS

HDL cholesterol levels measured in individuals with likely monogenic diabetes may be useful in screening for GCK-MODY and differentiation from T1DM and HNF1A-MODY, regardless of treatment or metabolic control.

Ishige okamurae ameliorates hyperglycemia and insulin resistance in C57BL/KsJ-db/db mice

We investigated the effect of Ishige okamurae extract on blood glucose level and insulin resistance in C57BL/-KsJ-db/db mice. We administered a standard AIN-93G diet with or without IOE to the animals for 6 weeks. After 6 weeks, blood glucose level was improved and blood glycosylated hemoglobin levels were lowered in sample group mice as compared to those in the diabetic control group mice. Hyperinsulinemia was reduced in the I. okamurae extract group mice with type 2 diabetes. With regard to hepatic glucose metabolic enzyme activities, glucokinase activity was enhanced in the IOE group mice, while glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities in the IOE group mice were significantly lowered than those in the diabetic control group mice. In addition, the hepatic glycogen content was elevated in the IOE group as compared to that in the diabetic control group. The homeostatic index of insulin resistance was lower in the I. okamurae extract group mice than in the diabetic control group mice. These results suggest that a dietary supplement of I. okamurae extract lowers the blood glucose level by altering the hepatic glucose metabolic enzyme activities and improves insulin resistance.

Anti-diabetic effects of lemon balm (Melissa officinalis) essential oil on glucose- and lipid-regulating enzymes in type 2 diabetic mice

The antioxidant activity of lemon balm (Melissa officinalis) essential oil (LBEO) on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and its hypoglycaemic effect in db/db mice were investigated. LBEO scavenged 97 % of DPPH radicals at a 270-fold dilution. Mice administered LBEO (0·015 mg/d) for 6 weeks showed significantly reduced blood glucose (65 %; P < 0·05) and TAG concentrations, improved glucose tolerance, as assessed by an oral glucose tolerance test, and significantly higher serum insulin levels, compared with the control group. The hypoglycaemic mechanism of LBEO was further explored via gene and protein expression analyses using RT-PCR and Western blotting, respectively. Among all glucose metabolism-related genes studied, hepatic glucokinase and GLUT4, as well as adipocyte GLUT4, PPAR-γ, PPAR-α and SREBP-1c expression, were significantly up-regulated, whereas glucose-6-phosphatase and phosphoenolpyruvate carboxykinase expression was down-regulated in the livers of the LBEO group. The results further suggest that LBEO administered at low concentrations is an efficient hypoglycaemic agent, probably due to enhanced glucose uptake and metabolism in the liver and adipose tissue and the inhibition of gluconeogenesis in the liver.

Ameliorative effect of Eucommia ulmoides Oliv. leaves extract (ELE) on insulin resistance and abnormal perivascular innervation in fructose-drinking rats

AIM OF THE STUDY

Eucommia ulmoides Oliv. leaf is a traditional Chinese medicine that exhibits an anti-diabetic action. This study was designed to investigate whether long-term administration of Eucommia ulmoides Oliv. leaves extract (ELE) ameliorates pre-diabetic state of insulin resistance and abnormal perivascular innervation in the hyperinsulinemic state.

MATERIALS AND METHODS

ELE at doses of 500 and 1000mg/kg was administered orally once daily for 4 weeks in fructose-drinking rats (FDRs). Plasma levels of insulin, blood glucose levels, and perivascular innervation were assessed using biochemical and immunohistochemical methods.

RESULTS

FDR showed significant increase in plasma levels of insulin, an index for insulin resistance (Homeostasis Model Assessment ratio-HOMA-IR) and systolic blood pressure (SBP), but not blood glucose levels, as compared with control rats. Immunohistochemical study showed significantly greater density of tyrosine hydroxylase (TH)-like immunoreactivity (LI)-containing nerves and significantly lower density of calcitonin gene-related peptide (CGRP)-LI-containing nerves in mesenteric arteries of FDR than those in control. A 4-week treatment with ELE (500 and 1000mg/kg, p.o.) significantly decreased plasma levels of insulin and HOMA-IR without affecting blood glucose levels and significantly lowered SBP in FDR. ELE treatment in FDR resulted in significant increase in CGRP-LI never fiber density and significant decrease in TH-LI never fiber density in mesenteric arteries of FDR.

CONCLUSIONS

These results suggest that long-term ELE treatment effectively prevents insulin resistance development and ameliorates abnormal perivascular innervation in FDR.

Leucas cephalotes regulates carbohydrate and lipid metabolism and improves antioxidant status in IDDM and NIDDM rats

ETHNOPHARMACOLOGICAL RELEVANCE

Leucas cephalotes (Roth.) Spreng. (Laminaceae) is an ayurvedic traditional medicinal plant used in India, Nepal and Pakistan to treat several ailments including diabetes.

AIM OF THE STUDY

The aim of the present study is to investigate the antidiabetic, antihyperlipaemic and antioxidant activities of Leucas cephalotes for its purported use in diabetes.

MATERIALS AND METHODS

The ethanol extract of leaves of Leucas cephalotes was administered (150, 300 and 450 mg kg(-1)bw) to diabetes induced (IDDM and NIDDM) rats and carbohydrate, lipid, antioxidant, urea and creatinine profiles were assessed.

RESULTS

All the three doses of extract decreased plasma glucose and lipid profiles and, improved the antioxidant status of both types of diabetic rats. The extract administration improved hepatic glycogen content and hexokinase activity, decreased glucose-6-phosphatase activity, blood urea, creatinine contents and decreased lipid peroxidation in diabetic rats. Of the three doses used, 450 mg kg(-1)bw dose was found to be more potent in its effects comparable to those of glibenclamide and metformin.

CONCLUSION

Leucas cephalotes regulates both carbohydrate and lipid metabolism and, improves body antioxidant defense systems in both types of diabetes.

Protective effects of Eucommia ulmoides Oliv. bark and leaf on amyloid β-induced cytotoxicity

The objectives of this study were to investigate the protective effects of Eucommia ulmoides Oliv. (EUO) bark and leaf against cytotoxicity induced by amyloid-β peptide (Aβ) and to explore their active components. The PC-12 cells injury mediated by Aβ(25-35) was employed to assess the neuroprotective effects of EUO bark, EUO leaf and various compounds. Intracellular Ca(2+) determination, MTT reduction assay, lactate dehydrogenase leakage evaluation and HO33258/PI staining were used to quantitatively or qualitatively evaluate cell viability and injury. The organic solvents partition and the macroporous resin separation were also applied to tracing the active constituents of EUO bark. Moreover, the effects of 8 compounds (3 iridoid glucoside, 3 phenylpripanoids and 2 flavonoids) were tested to identify the active compounds of EUO leaf. The results demonstrated that the water extracts of EUO barks and leaves, geniposidic acid and chlorogenic acid could efficiently protect PC-12 cells against the cytotoxicity of Aβ(25-35). This research suggests that EUO may represent a potential treatment strategy for Alzheimer's disease. Meanwhile, geniposidic acid and chlorogenic acid are the major active constituents of EUO barks and leaves, respectively.

Potential hypoglycemic effect of an ethanol extract of Gynostemma pentaphyllum in C57BL/KsJ-db/db mice

This study was conducted to evaluate the antihyperglycemic effect of an extract of Gynostemma pentaphyllum Makino, containing standardized concentrations of gypenosides, in C57BL/KSJ-db/db mice. For 5 weeks, animals were provided a standard AIN-76 diet (normal control) with rosiglitazone (0.005%, wt/wt) or two different doses of G. pentaphyllum ethanol extract (GPE) of the plant leaves (0.0025% and 0.01%, wt/wt). After the experimental period, the blood glucose levels of the high-dose GPE- and rosiglitazone-supplemented groups were significantly lower than that of the control group. The plasma insulin concentrations of the GPE-supplemented mice were significantly elevated compared to the control group. The GPE and rosiglitazone treatments profoundly affected the intraperitoneal insulin tolerance test compared to the control group, but not the intraperitoneal glucose tolerance test. In the evaluation of effects on hepatic glucose metabolism, the ratios of glucokinase/glucose-6-phosphatase activities in the high-dose GPE- and rosiglitazone-supplemented groups were prominently higher than that of the control group. The histology of the pancreatic islets revealed that the insulin-positive beta-cell numbers were higher in the high-dose GPE- and rosiglitazone-supplemented groups than in the control group. These results suggest that the supplementation of high-dose GPE (0.01%) in the diet lowers the blood glucose level by altering the hepatic glucose metabolic enzyme activities.

Nonalcoholic steatohepatitis (NASH) in ob/ob mice treated with yo jyo hen shi ko (YHK): effects on peroxisome proliferator-activated receptors (PPARs) and microsomal triglyceride transfer protein (MTP)

YHK has antioxidant properties, has a hypoglycemic effect, and may reduce plasma lipid levels. In this study, we examined the hepatic expression of PPAR-alpha and -gamma and MTP in ob/ob mice receiving or not receiving YHK. Ob/ob mice were assigned to receive oral YHK (20 mg/kg/day) fed solution (methionine/choline-deficient [MCD] diet+YHK group) or vehicle (MCD group) by gavage for 4 weeks. Liver fragments were collected for histologic examination and mRNA isolation. PPAR-alpha and -gamma and MTP gene expression was examined by RT-qPCR. YHK treatment was associated with NASH prevention, weight loss, and reduction of visceral fat and of serum concentrations of aminotransferases in comparison to the MCD group. YHK promoted an increment in PPAR-alpha and MTP and a decrement in PPAR-gamma mRNA contents. These findings suggest that modulation of PPAR-alpha and -gamma and MTP RNA expression may be implicated in the protective effect of YHK in experimental NASH, limiting hepatocyte lipid accumulation.

Eucommia ulmoidesOliver Leaf Extract Increases Endogenous Antioxidant Activity in Type 2 Diabetic Mice

Eucommia ulmoides Oliver (Du-zhong) leaf extract was investigated for its antioxidant effects in type 2 diabetic animals, C57BL/KsJ-db/db mice. Du-zhong extract equivalent to 1% dried whole Du-zhong leaf (0.187 g of extract/100 g of diet) was added to the experimental diets for 6 weeks. The Du-zhong extract supplement significantly lowered blood glucose concentrations and elevated plasma paraoxonase activity compared with the control group. The activities of erythrocyte superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were significantly higher in the Du-zhong group compared with the control group, while glutathione reductase (GR) activity was not different between groups. The activities of SOD, GSH-Px, and GR in liver and kidney were not affected by Du-zhong extract supplementation, whereas the CAT activity was significantly higher in the Du-zhong group than in the control group. Du-zhong extract supplementation resulted in lower levels of hydrogen peroxide and lipid peroxide in erythrocytes, liver, and kidney. These results suggest that the antioxidant activity of Du-zhong extract is potentially beneficial for the prevention and management of complications of type 2 diabetes.