Synthesis and antihyperglycemic activity of phenolic C-glycosides

Various phenolic C-glycosides were evaluated for their in vitro and in vivo antihyperglycemic activity employing glucose uptake by rat muscle cell lines (L-6) and low dosed-streptozotocin-induced diabetic rats, respectively. Some of phenolic C-glycosides were isolated from Pterocarpus marsupium and Ulmus wallichiana and other were synthesized by unprotected sugar and phloroacetophenone using Sc(OTf)₃ in aqueous ethanol. Eight among tested compounds showed significant lowering of blood glucose level on low dosed-streptozotocin-induced diabetic rats. The compound 24 lowered the blood glucose levels by 34.9% and 33.6% during 0-5 h and 0-24 h, respectively, at the dose of 25 mg/kg body weight which is comparable to standard antidiabetic drug metformin.     

Synthesis and antihyperglycemic activity of chalcone based aryloxypropanolamines

A series of aryloxypropanolamines (5a-r) of different chalcones (3a-e) were synthesized and evaluated for antihyperglycemic activity in sucrose loaded (SLM) and streptozotocin (STZ) induced diabetic animal models. Among them compounds 5a, g, m, o, p and r showed significant reduction in blood glucose levels in both SLM and STZ animal models.     

Synthesis and antihyperglycemic activity of novel N-acyl-2-arylethylamines and N-acyl-3-coumarylamines

A series of novel N-acyl-2-arylethylamines and N-acyl-3-coumarylamines were synthesized and evaluated for their antihyperglycemic activity. Compounds 3g and 6d exhibited lowering of postprandial plasma glucose by 30.7%, 23.3% in SLM and 25.6%, 25.4% in STZ models respectively which is significant compared to metformin and glybenclamide. Other compounds exhibited moderate to good activity ranging from 19.5% to 32.8% in SLM and 3.26% to 25.4% in STZ models.     

Synthesis and antihyperglycemic activity profiles of novel thiazolidinedione derivatives

A number of thiazolidine-2,4-diones derivatives having carboxylic ester appendage at N-3 were synthesized and their antihyperglycemic activity was evaluated. Many of these derivatives as well as their corresponding carboxylic acid showed significant improvement on post-prandial hyperglycemia in normal rats, in contrast to their poor agonist activity at PPARgamma.     

Synthesis and in vivo antihyperglycemic activity of 5-(1H-pyrazol-3-yl)methyl-1H-tetrazoles

A series of 5-[(5-aryl-1H-pyrazol-3-yl)methyl]-1H-tetrazoles 3a-h have been synthesized and evaluated for their in vivo antihyperglycemic activity. Some of the synthesized compounds have shown significant glucose lowering activity in male Sprague-Dawley rats in sucrose loaded model. These compounds were also evaluated for their peroxisome proliferator activated receptor gamma agonistic property, but none of them displayed any significant activity.     

Synthesis and antihyperglycemic activity of suitably functionalized 3H-quinazolin-4-ones

A series of 2-sec-amino-3H-quinazolin-4-ones (4a-p) and 4-sec-amino-2-chloroquinazolines (5a-b) have been synthesized by nucleophilic substitution reaction of 2-chloro-4(3H)-quinazolones (3) and 2,4-dichloroquinazolines (2) with amines, respectively. Most of the synthesized compounds were evaluated for antihyperglycemic activity but only 4a,b,d,j,o displayed significant reduction in blood glucose level in streptozotocin and sucrose loaded rat models.     

Synthesis and biological activity of novel alpha-substituted beta-phenylpropionic acids having pyridin-2-ylphenyl moiety as antihyperglycemic agents

We previously reported the identification of novel oximes having 5-benzyl-2,4-thiazolidinedione with antihyperglycemic activity. We now report the synthesis and biological activity of a novel series of oximes and amides having alpha-substituted-beta-phenylpropionic acids. In this series, we obtained potent PPAR alpha/gamma dual agonist (S)-9d, with which activation of PPAR alpha and PPAR gamma was considerably more potent than that of the reference compounds GW9578 22 and rosiglitazone 3, respectively. This means (S)-9d is of the strongest class of PPAR alpha/gamma dual agonists. In the course of this study, we also obtained 8h, which indicated potent plasma glucose lowering effect in spite of weak PPAR alpha/gamma agonistic activity.     

Design and synthesis of novel imidazoline derivatives with potent antihyperglycemic activity in a rat model of type 2 diabetes

Imidazoline derivatives have been reported to show antihyperglycemic activity in vivo. In the present study, we first showed that there was no correlation between the in vivo antidiabetic activity and the in vitro affinities for the I1/I2 binding sites for several substituted aryl imidazolines. Among these compounds, 2-(alpha-cyclohexyl-benzyl)-4,5-dihydro-1H-imidazole 2 exhibited potent antihyperglycemic properties. It was then chosen as lead compound. Thirty-six new derivatives were synthesized by replacing the cyclohexyl/benzyl group by various cyclic systems or the imidazoline ring by isosteric heterocycles. These compounds were evaluated in vivo for their antihyperglycemic activity using an oral glucose tolerance test (OGTT) in a rat model of type-2 diabetes obtained by giving a single intravenous (iv) injection of a low dose of streptozotocin to rats (STZ rats) and in normal rats. Nine compounds with an imidazoline moiety, possibly substituted by a methyl group, had a potent effect on the glucose tolerance in normal or STZ-diabetic rats, after an oral (po) administration of the test compound at a dose of 30 or 10 mg kg(-1), without any hypoglycemia. Replacement of the imidazoline ring by isosteric heterocycles resulted in a total loss of activity.     

Synthesis and In vivo anti-inflammatory activity of long-chain 2-amino-alcohols

The synthesis of optically pure long-chain 2-amino-alcohols and 1-O-dodecyl-2-deoxy-2-amino-sn-glycerol was carried out starting from L- or D-Boc-Ser(OBn)-ol by oxidation and consecutive Wittig reaction or etherification reaction. 2-Amino-oleyl alcohol was synthesized by reduction of the corresponding 2-amino-oleic acid. All the long chain amino-alcohols presented interesting inhibition of carrageenin-induced paw edema in rats (ED(50) from 0.017 to 0.010 mmol/kg).     

Synthesis and antihyperglycemic evaluation of various protoberberine derivatives

Various berberine derivatives (2-17) were synthesized and their antihyperglycemic activities were evaluated in a model of beta-cell-membrane chromatography and a model of alloxan-induced diabetes mice. The results indicated that compounds 5 and 14 exhibited antihyperglycemic activity. Their structure-activity relationships were discussed.     

2-O-carboxymethylpyrogallol derivatives as PTP1B inhibitors with antihyperglycemic activity

2-O-carboxymethylpyrogallol derivatives (4-17) were synthesized, with their in vitro inhibitory activities against PTP1B and in vivo antihyperglycemic effects examined. Compound 14, the most potent among the series, showed a K(i) value of 1.1 microM against PTP1B, 7-fold lower than that against TC-PTP. When compound 14 was fed to a high-fat diet-induced diabetic mouse model, significant improvements were observed in both the fasting glucose level and glucose tolerance.     

Synthesis,in vitro and computational studies of protein tyrosine phosphatase 1B inhibition of a small library of 2-arylsulfonylaminobenzothiazoles with antihyperglycemic activity

The 2-arylsulfonylaminobenzothiazole derivatives 1–27 were prepared using a one step reaction. The in vitro inhibitory activity of the compounds against protein tyrosine phosphatase 1B (PTP-1B) was evaluated. Compounds 4 and 16 are rapid reversible (mixed-type) inhibitors of PTP-1B with IC₅₀ values in the low micromolar range. The most active compounds (4 and 16) were docked into the crystal structure of PTP-1B. Docking results indicate potential hydrogen bond interactions between the nitro group in both compounds and the catalytic amino acid residues Arg 221 and Ser 216. Both compounds were evaluated for their in vivo antihyperglycemic activity in a type 2 diabetes mellitus rat model, showing significant lowering of plasma glucose concentration, during the 7 h post-intragastric administration.     

Synthesis and antihyperglycemic evaluation of new 2-hydrazolyl-4-thiazolidinone-5-carboxylic acids having pyrazolyl pharmacophores

In the search of new antihyperglycemic agents and following rational approach of drug designing here new 2-hydrazolyl-4-thiazolidinone-5-carboxylic acids (4a–g) with pyrazolyl pharmacophore have been synthesized via thia Michael addition reaction of 1-((3-(4-substituted phenyl)-1-phenyl-1H-pyrazol-4-yl)methylene)thiosemicarbazides (3a–g) with maleic anhydride. The required precursors, (3a–g) were obtained by condensing known 3-(4-substituted phenyl)-1-phenyl-1H-pyrazole-4-carbaldehydes (1a–g) with thiosemicarbazide in ethanol. The newly synthesized compounds (4a–g) have been evaluated for the antihyperglycemic activity in sucrose loaded rat model and among these compounds 4d, 4f and 4g have displayed significant antihyperglycemic activity.     

Synthesis of dammarane-type triterpenoids with anti-inflammatory activity in vivo

The 17-alpha-substituted triterpene 1 [(17alpha)-23-(E)-dammara-20,23-diene-3beta,25-diol] showed promising activity in animal models of immunosuppression and inflammation. Using a mouse model for inflammatory skin diseases (oxazolone-induced allergic contact dermatitis, ACD) as the directing in vivo test system, Structure-activity-relationship studies with the aim to understand the necessary structural requirements for the biological activity of 1 were conducted. Furthermore, we anticipated to identify biologically active compounds with the 17beta configuration, which are thermodynamically more stable and much easier to synthesize. This was achieved by identifying the 17-beta substituted dammarane 5B and its analogues.     

Synthesis and in vitro and in vivo antimycobacterial activity of isonicotinoyl hydrazones

The purpose of this study was to prepare various isoniazid derivatives by introducing the isoniazid pharmacophore into several molecules and screening for antimycobacterial activity. Ortho-hydroxy acetophenone reacts with isoniazid to form acid hydrazones. The C-Mannich bases of the above acid hydrazones were prepared by reacting them with formaldehyde and various secondary amines. The synthesized compounds were screened against M. tuberculosis H(37)R(v) using the alamar blue susceptibility test. The synthesized compounds inhibit Mycobacterium tuberculosis strain H(37)R(v) with minimum inhibitory concentrations ranging from 0.56 to 4.61 microM. Compound N'-{1-[2-hydroxy-3-(piperazin-1-ylmethyl)phenyl]ethylidene}isonicotinohydrazide 8 was found to be the most active compound with an MIC of 0.56 microM, and was more potent than isoniazid (MIC of 2.04 microM). After 10 days of treatment, compound 8 decreased the bacterial load in murine lung tissue by 3.7-log10 as compared to controls, which was equipotent to isoniazid. The results demonstrate the potential and importance of developing new isoniazid derivatives against mycobacterial infections.     

Synthesis and antimalarial activity of urenyl Bis-chalcone in vitro and in vivo

Some novel derivatives of Bis-chalcone were synthesized and characterized by their physical and spectral data. All the synthesized compounds were subsequently screened for in vitro globin hydrolysis, β-hematin formation, and murine Plasmodium berghei, using chloroquine as the reference drug. Most of the synthesized compounds exhibited mild to moderate susceptibilities toward the parasite in comparison with the standard. The most active antimalarial compound was 1,1-Bis-[(3′,4′-N-(urenylphenyl)-3-(3″,4″,5″-trimethoxyphenyl)]-2-propen-1-one 5, with a percentage of inhibition of heme polymerization of 87.05?±?0.77, and this compound increased the survival time after infection, reduce the parasitemia and delay the progression of malaria.     

Synthesis and in vivo diuretic activity of some novel pyrimidine derivatives

A series of 1,6-dihydropyrimidine-2-amine derivatives and 1,6-dihydropyrimidine-2-thiol derivatives were synthesized by the reaction of substituted 1,3-diphenylprop-2-en-1-one (chalcones) with guanidine hydrochloride and thiourea, respectively. All the synthesized compounds were in good agreement with elemental and spectral data. The synthesized compounds were screened in vivo for diuretic activity. The four compounds 2d, 2e, 3d and 3e, which showed moderate to good diuretic activity, were evaluated for their toxicity studies and none of the compounds showed any toxicity of the liver as compared with control. However, compounds 3e and 3d showed diuretic properties more than that of standard (acetazolamide) and were long acting. Overall, compound 3e, 6-(2,6-dichlorophenyl)-4-(pyridin-2-yl)-1,6-dihydropyrimidine-2-thiol, was found to be the most promising candidate of the series.     

Coagulanolide, a withanolide from Withania coagulans fruits and antihyperglycemic activity

One new withanolide, (17S,20S,22R)-14alpha,15alpha,17beta,20beta-tetrahydroxy-1-oxowitha-2,5,24-trienolide) named coagulanolide (4) along with four known withanolides 1-3 and 5 have been isolated from Withania coagulans fruits and their structures were elucidated by spectroscopic techniques. The compounds 1-5 showed significant inhibition on postprandial rise in hyperglycemia post-sucrose load in normoglycemic rats as well as streptozotocin-induced diabetic rats. The compound 5 also showed significant fall on fasting blood glucose profile and improved the glucose tolerance of db/db mice. Further compound 5 showed antidyslipidemic activity in db/db mice. The median effective dose of the compound 5 was determined to be around 25 mg/kg in streptozotocin-induced diabetic rats, which is comparable to the standard antidiabetic drug metformin. Our results provide further support to explain the traditional use of W. coagulans as antihyperglycemic cum antidyslipidemic agent by the traditional medical practitioners.     

Synthesis and structure-activity relationship studies of cinnamic acid-based novel thiazolidinedione antihyperglycemic agents

A number of 2,4-thiazolidinedione derivatives of -phenyl substituted cinnamic acid were synthesized and studied for their PPAR agonist activity. The E-isomer of cinnamic acid, 11, showed moderate PPAR transactivation. The corresponding Z-isomer, 23, and double bond reduced derivative, 15, were found to be much less potent. Although the E-isomer showed a moderate PPAR gamma transactivation, it demonstrated a strong glucose-lowering effect in a genetic rodent model of diabetes. Results of pharmacokinetic, metabolism and permeability studies are consistent with 11 being an active prodrug with an active metabolite, 14, that has similar glucose lowering and PPAR gamma agonist properties.     

Synthesis and evaluation of phenylequine for antimalarial activity in vitro and in vivo

Synthesis of the potent antiplasmodial 4-aminoquinoline, phenylequine (PQ), is reported for the first time. PQ and the two analogues show increased efficacy in moving from the chloroquine sensitive D10 to the chloroquine resistant K1 strain in vitro. The in vivo efficacy of PQ, and salts thereof, have been determined in Plasmodium berghei ANKA and Plasmodium yoelii. Phenylequine hydrochloride has shown an ED₅₀ of 0.81 in P. yoelii (cf chloroquine ED₅₀ = 1.31).