Hypoglycemic oligostilbenes from the stems of Caragana sinica.

Six new oligostilbenes, carastilphenols A-E (1-5) and (-)-hopeachinol B (6), with three reported oligostilbenes were obtained from the stems of Caragana sinica. The structures of compounds 1-6 were determined by comprehensive spectroscopy analysis, and their absolute configurations were determined by electronic circular dichroism calculations. Thus, natural tetrastilbenes were determined as absolute configuration for the first time. Also, we did several pharmacological essays. In the antiviral tests, compounds 2, 4 and 6 showed moderate anti-coxsackie virus B3 type (CVB3) effect on Vero cells activities in vitro with IC50 values of 19.2 âˆ¼ 69.3 µM; and compounds 3 and 4 showed different levels of anti-respiratory syncytial virus (RSV) effect on Hep2 cells activities in vitro with IC50 values of 23.1 and 33.3 µM, respectively. As for hypoglycemic activity, compounds 6-9 (10 µM) showed the inhibition of α-glucosidase in vitro with IC50 values of 0.1 âˆ¼ 0.4 µM; and compound 7 showed significant inhibition (88.8%, 10 µM) of protein tyrosine phosphatase 1B (PTP1B) with IC50 value of 1.1 µM in vitro.

Dianthrone derivatives from Polygonum multiflorum Thunb: Anti-diabetic activity, structure-activity relationships (SARs), and mode of action.

PTP1B plays an important role as a key negative regulator of tyrosine phosphorylation associated with insulin receptor signaling in the therapy for diabetes and obesity. In this study, the anti-diabetic activity of dianthrone derivatives from Polygonum multiflorum Thunb., as well as the structure-activity relationships, mechanism, and molecular docking were explored. Among these analogs, trans-emodin dianthrone (compound 1) enhances insulin sensitivity by upregulating the insulin signaling pathway in HepG2 cells and displays considerable anti-diabetic activity in db/db mice. By using photoaffinity labeling and mass spectrometry-based proteomics, we discovered that trans-emodin dianthrone (compound 1) may bind to PTP1B allosteric pocket at helix α6/α7, which provides fresh insight into the identification of novel anti-diabetic agents.

Bioactive monoterpene phenol dimers from the fruits of Psoralea corylifolia L.

Nine undescribed monoterpene phenol dimers, bisbakuchiols D-L (1-9), were isolated from the fruits of Psoralea corylifolia L. Their structures were elucidated based on extensive spectral analysis. The absolute configurations of 1-9 were specified by experimental and quantum chemical calculations of ECD spectra, and that of 1 was further established by X-ray diffraction analysis using Cu Kα radiation. Bisbakuchiols (1-4) were composed of two bakuchiols, one of which was cyclized via a C-7'/ C-12' single bond to form a six-member ring, and connect to each other by C-4-O-C-13' bonds. Bisbakuchiols (7-9) had a pyran ring by linkage of C-8-O-C-12. In the enzyme assay, compounds 5 and 9 exhibited significant PTP1B inhibitory activities with IC50 values of 0.69 and 0.73 µM, and compounds 1 and 3 showed moderate PTP1B inhibitory activities. Furthermore, a molecular docking simulation of PTP1B and active compounds 5 and 9 showed that these active compounds possess low binding affinities ranging from -6.9 to -7.1 kcal/mol.

Identification of natural products as selective PTP1B inhibitors via virtual screening.

Protein tyrosine phosphatase 1B (PTP1B) is emerging as a promising yet challenging target for drug discovery. To identify natural products as new prototypes for PTP1B inhibitors, we employed a hierarchical protocol combining ligand-based and structure-based approaches for virtual screening against natural product libraries. Twenty-six compounds were prioritized for enzymatic evaluation against PTP1B, and ten of them were recognized as potent PTP1B inhibitors with IC50 values at the micromolar level. Notably, nine compounds demonstrated evident selectivity to PTP1B over four other PTPs, including the most homologous T-cell protein tyrosine phosphatase (TCPTP). The results implicated that the structural uniqueness of the natural products might be a potential solution to the selectivity issue associated with the target PTP1B.

[Design, synthesis and biological evaluation of oxadiazole derivatives as xanthine oxidase inhibitors].

Xanthine oxidase (XO) is an important target for the treatment of hyperuricemia and gout. Based on the two known non-purine xanthine oxidase inhibitors, febuxostat and topiroxostat, 14 oxadiazole derivatives have been designed and synthesized. These compounds have been evaluated against XO and five of them exhibited significant inhibitory activities at the concentrations below 10 µmol·L(-1).

[Investigating the effects of compound WS090152 on non-alcoholic fatty liver in mice].

To investigate the effects and the mechanism of compound WS090152 on non-alcoholic fatty liver (NAFL), the compound was administrated in C57BL/6J mice fed a high fat diet at 50 mg·kg(-1) by lavage. The lipid accumulation in liver was determined by the content of hepatic triglyceride (TG) and the histological pathological analysis. The levels of body weight gain, serum total cholesterol (TC) and TG were measured to evaluate lipid metabolism. Insulin sensitivity was determined by glucose infusion rate (GIR) value in hyperinsulinemic-euglycemic clamp test. The expression of related proteins in liver was measured by Western blot. The effect on the target protein tyrosine phosphatase 1B (PTP1B) was assessed by the activity of recombinate human PTP1B in vitro, and by the expressions of PTP1B in vivo, respectively. The content of hepatic TG (P<0.05) and the pathological changes of the livers (P<0.01) were attenuated, insulin resistance was improved, (P<0.01), and the levels of serum TC (P<0.01) and serum TG (P<0.05) were reduced by WS090152 treatment in the mice. The recombinant h PTP1B activity was significantly inhibited with IC50 value of 0.34 µmol·L(-1); the expression of PTP1B was significantly downregulated, and the phosphorylation of its downstream insulin receptor (IR), and AKT was upregulated by WS090152 administration in the livers of NAFL mice. The expression of hepatic lipogenesis-related proteins-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) was attenuated. These results suggest that compound WS090152 can ameliorate NAFL by increasing insulin sensitivity and decreasing hepatic lipogenesis probably through inhibition of PTP1B.

[Prescription of Jingdan Yimin for treatment of metabolic syndrome].

Based on the theory of traditional Chinese medicine, modern methods for drug investigation such as molecular targets in vitro and effects in vivo were used to study the prescription of Jingdan Yimin(JD), including selection of raw materials, composition, proportion, and effective dose of the compounds for treatment of metabolic syndrome. The IRF mice models, characterized by insulin resistance and hypercholesterolemia, were induced by high fat diet. The insulin sensitivity was estimated with insulin tolerance test(ITT) and glucose tolerance test(GTT); the levels of blood glucose and total cholesterol(TC), and the activities of α-glucosidase, protein tyrosine phosphatase 1B(PTP1B), and fructose phosphate amide transferase(GFAT)were measured with biochemical methods, respectively. The sample H13(h) extracted from Rhodiola crenulata, Y12(y) from Cordyceps militaris, and D(d) from Rheum palmatum were selected according to the inhibition activity on both PTP1B and α-glucosidase in vitro, regulation on hypercholesterolemia in IRF mice, and effects on GFAT activity, respectively; their synergistic effects on the treatment of metabolic syndrome were determined in IRF mice; composition proportion of h∶y∶d was measured in accordance with the results of L8(27) orthogonal experiments targeting on the inhibition of both PTP1B and α-glucosidase; finally, the effective dose was assessed based on the effects on IGT and hypercholesterolemia, respectively, in IRF mice. In conclusion, the prescription JD is composed by R. crenulata, C. militaris, and R. palmatum with the rate of 20∶1∶1, and its effective oral dose is 200 mg•kg⁻¹ for treatment of metabolic syndrome; its main mechanism is to inhibit the targets PTP1B and α-glucosidase. Monarch drug, R. crenulata, can clear away the lung-heat, tonify Qi, resolve stasis and nourish the heart. Adjuvant drug, C. militaris, can tonify the lung Qi and the kidney essence, strengthen waist and knee, accompanied with R. crenulata to enhance the function of invigorating lung and kidney. Assistant drug, rhubarb, can clear heat, detoxify, and remove blood stasis. These three herbs are compatible to show the effects of tonifying Qi, nourishing essence, clearing heat, reducing phlegm and resolving masses for the treatment of metabolic syndrome.

Effect of Hypericum perforatum L. extract on insulin resistance and lipid metabolic disorder in high-fat-diet induced obese mice.

Natural product Hypericum perforatum L. has been used in folk medicine to improve mental performance. However, the effect of H. perforatum L. on metabolism is still unknown. In order to test whether H. perforatum L. extract (EHP) has an effect on metabolic syndrome, we treated diet induced obese (DIO) C57BL/6J mice with the extract. The chemical characters of EHP were investigated with thin-layer chromatography, ultraviolet, high-performance liquid chromatography (HPLC), and HPLC-mass spectrometry fingerprint analysis. Oral glucose tolerance test (OGTT), insulin tolerance test (ITT), and the glucose infusion rate (GIR) in hyperinsulinemic-euglycemic clamp test were performed to evaluate the glucose metabolism and insulin sensitivity. Skeletal muscle was examined for lipid metabolism. The results suggest that EHP can significantly improve the glucose and lipid metabolism in DIO mice. In vitro, EHP inhibited the catalytic activity of recombinant human protein tyrosine phosphatase 1B (PTP1B) and reduced the protein and mRNA levels of PTP1B in the skeletal muscle. Moreover, expressions of genes related to fatty acid uptake and oxidation were changed by EHP in the skeletal muscle. These results suggest that EHP may improve insulin resistance and lipid metabolism in DIO mice.

[The effects of compound CX09040 on the inhibition of PTP1B and protection of pancreatic ß cells].

To investigate the effects of 2-(4-methoxycarbonyl-2-tetradecyloxyphenyl)carbamoylbenzoic acid (CX09040) on protecting pancreatic ß cells, the ß cell dysfunction model mice were induced by injection of alloxan into the caudal vein of ICR mice, and were treated with compound CX09040. Liraglutide was used as the positive control drug. The amount and the size of islets observed in pathological sections were calculated to evaluate the ß cell mass; the glucose stimulated insulin secretion (GSIS) test was applied to estimate the ß cell secretary function; the oral glucose tolerance test (OGTT) was taken to observe the glucose metabolism in mice; the expressions of protein in pancreas were detected by Western blotting. The effects on the target protein tyrosine phosphatase 1B (PTP1B) were assessed by the PTP1B activities of both recombinant protein and the intracellular enzyme, and by the PTP1B expression in the pancreas of mice, separately. As the results, with the treatment of CX09040 in alloxan-induced ß cell dysfunction mice, the islet amount (P<0.05) and size (P<0.05) increased significantly, the changes of serum insulin in GSIS (P<0.01) and the values of acute insulin response (AIR, P<0.01) were enhanced, compared to those in model group; the impaired glucose tolerance was also ameliorated by CX09040 with the decrease of the values of area under curve (AUC, P<0.01). The activation of the signaling pathways related to ß cell proliferation was enhanced by increasing the levels of p-Akt/Akt (P<0.01), p-FoxO1/FoxOl (P<0.001) and PDX-1 (P<0.01). The effects of CX09040 on PTP1B were observed by inhibiting the recombinant hPTP1B activity with IC50 value of 2.78x 10(-7) mol.L-1, reducing the intracellular PTP1B activity of 72.8% (P<0.001), suppressing the PTP1B expression (P<0.001) and up-regulating p-IRß/IRß (P<0.01) in pancreas of the ß cell dysfunction mice, separately. In conclusion, compound CX09040 showed significant protection effects against the dysfunction of ß cell of mice by enlarging the pancreatic ß cell mass and increasing the glucose-induced insulin secretion; its major mechanism may be the inhibition on target PTP1B and the succedent up-regulation of ß cell proliferation.

[SAR of benzoyl sulfathiazole derivatives as PTP1B inhibitors].

Protein tyrosine phosphatase (PTP) 1B is a potential target for the treatment of diabetes and obesity. We have previously identified the benzoyl sulfathiazole derivative II as a non-competitive PTP1B inhibitor with in vivo insulin sensitizing effects. Preliminary SAR study on this compound series has been carried out herein, and thirteen new compounds have been designed and synthesized. Among them, compound 10 exhibited potent inhibition against human recombinant PTP1B with the IC50 value of 3.97 micromol x L(-1), and is comparable to that of compound II.

Chiral separation and bioactivities of six pairs of enantiomeric dilignans from Magnolia officinalis var. biloba.

Six pairs of enantiomeric dilignans, (+)/(-)-magdiligols A-F, have been isolated from an ethanolic extract of the barks of Magnolia officinalis var. biloba. Their chemical structures were elucidated by extensive spectroscopic analyses, NMR calculation with DP4+ analysis, and the electronic circular dichroism spectra calculation. (+)/(-)-1-3 possessed a dihydrobenzopyran ring, while a propyl chain of 1 was linked via ether bond. (+)/(-)-Magdiligols D and E ((+)/(-)-4 and 5) were dilignans possessing a furan ring. (+)-Magdiligol B ((+)/(-)-2), (+)/(-)-magdiligol C ((+)/(-)-3), and racemes 2, 3, and 5 showed potential hepatoprotective effects against APAP-induced HepG2 cell damage, increased the cell viability from 65.4% to 72.7, 78.7.76.6, 73.9, 77.9 and 73.2%, via decreasing the level of the live enzymes ALH and LDH consistently. (+)/(-)-Magdiligols B-D ((+)/(-)-2-4) and (+)/(-)-magdiligol F ((+)/(-)-6) exhibited significant antioxidative activity. (+)/(-)-Magdiligols B-C ((+)/(-)-2 and 3), (-)-magdiligol D ((-)-4), and (+)-magdiligol E ((+)-5) displayed significant PTP1B inhibitory activity with IC50 values 1.41-3.42 µM. (+)/(-)-Magdiligol B ((+)/(-)-2), and its raceme (2) demonstrated α-glucosidase inhibitory activity with the IC50 values 1.47, 2.88 and 1.85 µM, respectively.

Design, synthesis and insulin-sensitising effects of novel PTP1B inhibitors.

Fifteen novel sulfathiazole-related compounds were designed as PTP1B inhibitors based on a previously reported allosteric inhibitor (1) of PTP1B. These compounds were synthesized and evaluated against human recombinant PTP1B. Six compounds (3, 4, 8 and 14-16) exhibited significant inhibitory activity against PTP1B. The most active compound (16) showed IC50 value of 3.2 µM and kinetic analysis indicated that it is a non-competitive inhibitor of PTP1B. Furthermore, compound 16 demonstrated excellent selectivity to PTP1B over other PTPs. It also displayed in vivo insulin sensitizing effect in the insulin resistant mice.

Discovery of novel PTP1B inhibitors via pharmacophore-oriented scaffold hopping from Ertiprotafib.

An integrated molecular design strategy combining pharmacophore recognition and scaffold hopping was exploited to discover novel PTP1B inhibitors based on the known PTP1B inhibitor Ertiprotafib. A composite pharmacophore model was proposed from the interaction mode of Ertiprotafib, and 21 diverse molecules from five distinct structural classes were designed and synthesized accordingly. New compounds with considerable inhibition against PTP1B were identified from each series, and the most active compound 3a showed IC50 value of 1.3 µmol L(-1) against human recombinant PTP1B. Docking study indicated that the new inhibitors assumed binding modes similar to that of Ertiprotafib.

[Investigation of a compound, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum, on metabolic syndrome treatment. V--Mechanisms on improving glucose metabolic disorders].

To investigate the mechanisms of a compound (FF16), compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum, on glucose metabolic disorders, the IRF mice charactered with insulin resistance and glucose metabolic disorders induced by high-fat diet in C57BL/6J mice were randomly divided into 3 groups; IRF, rosiglitazone (Rosi) and FF16. The glucose metabolism was evaluated by fasting blood glucose (FBG) levels and intraperitoneal glucose tolerance test (IPGTT). The insulin sensitivity was estimated by insulin tolerance test (ITT), fasting serum insulin levels and the index of HOMA-IR. The expressions of Akt and its phosphorylation levels, GSK3beta and its phosphorylation levels in liver were detected by Western Blot. The results showed that FF16 significantly improved the glucose metabolic disorders through reducing FBG by 15.1%, decreasing AUC values in glucose tolerance tests by 22.3%. FF16 significantly improved the insulin sensitivity through decreasing AUC values in insulin tolerance tests by 22.1%, reducing the levels of serum insulin by 42.9% and of HOMA-IR by 49.5%, comparing with model control, respectively. After the treatment with FF16, the levels of p-Akt and p-GSK3beta were increased by 116.4% and 24.9%, respectively, in the liver of IRF mice. In conclusion, compound FF16 could improve glucose metabolic disorders in IRF mice through enhancing the glyconeogenesis.

[Investigation of a compound, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rhum palmatum, on metabolic syndrome treatment. IV--Improving liver lipid accumulation].

To investigate the effects of a compound (FF16), compatibility of Rhodiola crenulata, Cordyceps militaris, and Rhum palmatum, on non-alcoholic fatty liver disease in IRF mice induced by high fat diet H&E stain was processed to evaluate the lipid accumulation in liver, and the dynamic microcirculation observation system was applied to determine hepatic microcirculation of IRF mice. Western blot was performed to evaluate IRS-2, HSL and ppar-alpha expression in liver. The results demonstrate that FF16 significantly decreased the liver lipid index and improved liver steatosis in IRF mice. Furthermore, FF16 could ameliorate hepatic microcirculation disturbance in IRF mice through enhancing RBC velocity and shear rates by 62.5% and 49.7%, increasing sinusoids perfusion by 70.0%, inhibiting adhered leukocytes in IRF mice. The abnormal expressions of IRS-2 and HSL were both reversed by the administration of FF16. In conclusion, FF16 could improve non-alcoholic fatty liver disease in IRF mice by improving insulin sensitivity, regulating lipid metabolism and improving microcirculation disturbance.

[Investigation of compound, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rhum palmatum, on metabolic syndrome treatment VI--improving hyperglycemia-mediated renal damage].

This study is to investigate the effects of a Chinese prescription (FF), compatibility of Rhodiola crenulata, Cordyceps militaris and Rheum palmatum, on nephropathy in type 1 diabetic rats induced by streptozocin. According to fasting blood glucose level, diabetic rats were divided into three groups: model group, insulin-treated group and FF-treated group. Parameters for evaluating the glucose & lipid metabolism and the renal function were monitored dynamically. Levels of oxidative stress were detected ten weeks later. The results show that FF could significantly decrease the level of serum glucose and lipid profiles, improve the renal functions by decreasing blood urea nitrogen, urine albumin excretion and urease activity; FF could also affect on oxidative stress. In conclusion, Chinese prescription FF could ameliorate hyperglycemia-mediated renal damage in type 1 diabetic rats. These effects may be related to its regulation on the metabolism of glucose and lipid, the microcirculation disturbance and the oxidative stress.

[Investigation of a compound, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum, on metabolic syndrome treatment II - improving obesity].

To investigate the effect of compound FF16, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum, on obesity, both the insulin resistant obese IRF mouse model induced by high fat diet and the spontaneous type 2 diabetes KKAy obese mouse model were used. The results showed that the body weights and the energy uptake were markedly reduced by compound FF16 in both IRF mice in dose-dependent manner and KKAy mice, respectively. Meanwhile, with the administration of FF16, the hypercholesterolemia and the hypertriglyceridemia were improved significantly in KKAy mice; and the levels of serum cholesterol and fatty index were decreased obviously, and the value of serum HDL-C was increased significantly in IRF mice, respectively. Moreover, the activity of a-glycosidase was inhibited by compound FF16 in vitro. In conclusion, FF16 could improve the obesity by inhibiting alpha-glycosidase activity.

[Investigation of a compound, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum on metabolic syndrome treatment III--controlling blood glucose].

Base on the improvement of compound FF16, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum, on both insulin resistance and obesity, its effects on type 2 diabetes (T2DM ) was investigated here. The results showed that the levels of fasting and no-fasting blood glucose were controlled in the spontaneous type 2 diabetes KKAy mice; the impaired glucose tolerance (IGT)was improved by decreasing significantly the values of the glucose peaks and the area under the blood glucose-time curve (AUC ) after glucose-loading in glucose tolerance test (OGTT) in both high-fat-diet-induced pre-diabetes IRF mice and KKAy mice, respectively. The pancreatic histopathological analysis showed that the increased islet amount, the enlarged islet area, and the lipid accumulation in the pancreas were reversed by FF16 treatment in both IRF mice and KKAy mice. In the palmitate-induced RINm5f cell model, FF16 could effectively reduce the apoptosis and enhance the glucose-stimulated insulin secretion, respectively. In conclusion, FF16 could improve the T2DM by protecting the pancreatic beta-cells.

Unusual N-pyridinium amino acid-type alkaloids from roots and rhizomes of Sophora tonkinensis Gagnep.

Two previously undescribed amino acid-type alkaloids with unusual N-pyridinium cation (1-2) and six known alkaloids (3-8), were isolated from the roots and rhizomes of Sophora tonkinensis Gapnea. Their structures were characterized by UV, IR, NMR, and HRESIMS spectroscopic data. The absolute configurations of compounds 1 and 2 were established through comparison of their experimental ECD spectra to the theoretical spectra of 2 calculated by TDDFT method. The plausible biosynthetic pathway of pyridinium was also proposed. Moreover, compound 4 exhibited weak XOD inhibitory activity with the inhibition rate of 65.8% at concentration of 10 µM.

[Design, synthesis and evaluation of malonic acid-based PTP1B inhibitors].

Protein tyrosine phosphatase (PTP) 1B is a potential target for the treatment of diabetes and obesity. Phosphotyrosine (pTyr) is the substrate for PTP1B dephosphorylation. Malonic acid moiety was used herein as a mimic of the phosphate group in pTyr, and novel malonic acid derivatives 1-7 were designed, synthesized and evaluated as PTP1B inhibitors. Results from enzymatic assays indicated that compounds 3 and 4 exhibited potent inhibition against human recombinant PTP1B with IC50 values of 7.66 and 1.88 micromol x L(-1), respectively.