Kuncha Madhusudana

Attenuation of insulin resistance, metabolic syndrome and hepatic oxidative stress by resveratrol in fructose-fed rats

Metabolic syndrome and oxidative stress are common complications of type 2 diabetes mellitus. The present study was designed to determine whether resveratrol, a widely used nutritional supplement, can improve insulin sensitivity, metabolic complication as well as hepatic oxidative stress in fructose-fed rats. Male Sprague Dawley rats (180-200 g) were divided into four groups with 8 animals each. Fructose-fed insulin resistant group (Dia) animals were fed 65% fructose (Research diet, USA) for a period of 8 weeks, whereas control group (Con) animals were fed 65% cornstarch (Research Diet, USA). Resveratrol, 10 mg/kg/day (Dia+Resv) or metformin 300 mg/kg/day (Dia+Met) were administered orally to the 65% fructose-fed rats for 8 weeks. At the end of the feeding schedule, Dia group had insulin resistance along with increased blood glucose, triglyceride, uric acid and nitric oxide (NO) levels. Significant (p<0.05) increase in hepatic TBARS and conjugated dienes, and significant (p<0.05) decrease in hepatic SOD and vitamin C was observed in Dia group compared to Con group. Administration of metformin or resveratrol significantly (p<0.05) normalized all the altered metabolic parameters. However, a marked insulin sensitizing action was only observed in the Dia+Resv group. Similarly, while metformin administration failed to normalize the increased TBARS levels and decreased SOD activity, resveratrol showed a more promising effect of all oxidative stress parameters measured in the present study. Attenuation of hepatic oxidative stress in fructose-fed rat liver after resveratrol administration was associated with significant (p<0.05) increase in nuclear level of NRF2 compared with other groups. The present study demonstrates that resveratrol is more effective than metformin in improving insulin sensitivity, and attenuating metabolic syndrome and hepatic oxidative stress in fructose-fed rats.

α-Glucosidase inhibitory antihyperglycemic activity of substituted chromenone derivatives

Series of 3,4- and 3,6-disubstituted chromenones including new chromenone derivatives were synthesized applying various synthetic strategies including Pechmann condensation, Knoevenagel condensation, Reimer-Tiemann reaction and Suzuki coupling in very good yields. Synthesized compounds (4a-z) were screened for in vitro alpha-glucosidase inhibitory and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activities. Majority of compounds displayed varying degrees of alpha-glucosidase inhibitory and DPPH scavenging activity. Compound 4x emerged as the most potent alpha-glucosidase inhibitor in present series of compounds owing to the presence of 3-acetyl-6-(6-methoxy-3-pyridyl) group on chromenone; however, it could not display DPPH scavenging activity and was found to be mixed non-competitive type inhibitor of rat intestinal alpha-glucosidase. When tested in vivo for antihyperglycemic activity in starch loaded Wistar rats, it displayed significant antihyperglycemic property. This is the first report assigning rat intestinal alpha-glucosidase inhibitory property for this class of new chromenones and presents new family of compounds possessing alpha-glucosidase inhibitory activities and antihyperglycemic property. Compound 4x may serve as an interesting new compound for the development of therapeutics targeted against diet-induced hyperglycemia in diabetes.

New furanoflavanoids, intestinal α-glucosidase inhibitory and free-radical (DPPH) scavenging, activity from antihyperglycemic root extract of Derris indica (Lam.)

A bioassay-guided fractionation and chemical examination of antihyperglycemic root extract of Derris indica resulted in isolation and characterization of two new furanoflavanoids (1, 2) along with thirteen known compounds (3-15). Their structures were determined on the basis of extensive spectroscopic (IR, MS, 1D and 2D NMR) data analysis and by comparison with the literature data. All the compounds were tested in vitro for intestinal alpha-glucosidase inhibitory and DPPH radical activity. New compounds (1, 2) displayed moderate intestinal alpha-glucosidase inhibitory as well as free radical scavenging activity. Other compounds also displayed varying degrees of moderate intestinal alpha-glucosidase inhibitory activity. Pongamol (6) displayed potent intestinal alpha-glucosidase inhibition.

Anti-inflammatory potential of thienopyridines as possible alternative to NSAIDs.

The present study was designed to evaluate the anti-inflammatory and antiarthritic activity of the new synthetic thienopyridine analogs. The anti-inflammatory activity of thienopyridines was assayed by using carrageenan; dextran and arachidonic acid induced paw edema models (acute), cotton pellet granuloma model (Sub acute) and Freunds complete adjuvant induced arthritis (chronic) in experimental rats. The compounds BN-4, BN-14 and BN-16 have shown significant inhibition of edema in carrageenan and arachidonic acid induced paw edema model at a dose of 100mg/kg compared to the dextran induced paw edema model and also showed significant inhibition in granuloma tissue formation and Freunds complete adjuvant induced arthritis in experimental rats. These thienopyridine analogs also inhibited the proinflammatory mediators such as Tumor necrosis factor (TNF)-α, Interleukin (IL)-1β and Nitric Oxide (NO) in Lipopolysaccharide (LPS) challenged murine macrophages. Ulcerogenecity study results revealed less ulcerogenic potential of BN-4, BN-14 and BN-16 compared to nonsteroidal anti-inflammatory drug (NSAID) indomethacin in rats. In conclusion, the new thienopyridine analogs were promising for the potential use as anti-inflammatory agents for both acute and chronic inflammatory disorders with low toxic effects.

Synthesis of antihyperglycemic, α-glucosidase inhibitory, and DPPH free radical scavenging furanochalcones

A series of furanochalcone derivatives have been designed and synthesized. Molecular modeling studies were carried out to probe into the mechanism of binding of chalcone inhibitors and understand the structure–activity relationship to identify the contribution of scaffolds and groups in the synthesized analogs to biological activity. The three-dimensional model of α-glucosidase was constructed based on the crystal structure family 31 α-glycosidase (PDB 1XSI) using Modeller9v5. Docking of the inhibitors on the built homology model revealed interactions in the active site region mostly with Asp 252, Tyr254, Gln523, and Arg571. 2D-QSAR models were generated with CODESSA using Heuristic method. The best predictive model was generated using three descriptors that gave a correlation co-efficient (r2) 0.9886 and cross-validate (r2) 0.9338. The synthesized compounds were screened against the α-glucosidase inhibition and DPPH radical scavenging properties. All the synthetic compounds displayed varying degrees of α-glucosidase inhibitory and DPPH scavenging activities. Compound 8c was found most potent α-glucosidase inhibitor though; it could not display DPPH scavenging activity. When tested in vivo for antihyperglycemic activity in starch-loaded Wistar rats, 8c was equally effective in reducing time-dependent hyperglycemia as to the standard drug, Acarbose. Compound 8c may serve as an interesting compound for the development of therapeutics targeted against diet-induced hyperglycemia in diabetes.

Mitigation of starch and glucose-induced postprandial glycemic excursion in rats by antioxidant-rich green-leafy vegetables' juice.

Objective: Consumption of green-leafy vegetables is being advocated beneficial for type 2 diabetes mellitus individuals possibly because they are cost effective source of potent biological antioxidants. This research analyzed various phytochemicals, free radicals scavenging antioxidant potentials and starch digesting enzymes inhibitory activities in fresh juice of nine green-leafy vegetables. Furthermore, this study also investigated influence of these vegetables juice on starch and glucose induced postprandial glycemic load. Materials and Methods: Phytochemical constituents, in vitro free radicals scavenging antioxidant and enzymes inhibitory activities were evaluated applying various reported methods. Post-prandial glycemic excursion was induced in rats pretreated with vegetables juice by oral administration of starch and glucose. Results: All the leafy vegetables juice displayed potent free radicals scavenging activities. Juice of amaranthus, rumex, palak and raphanus displayed potential anti-oxidative property by reducing H2O2 induced hemolysis in rats red blood cells RBCs. Ajwain and rumex juice showed pancreatic α-amylase inhibitory activity. Alternanthera, ajwain, methi, amaranthus and sowa leaves juice displayed intestinal α-glucosidase inhibitory activity. Juice of raphanus, ajwain and sowa significantly mitigated starch-induced postprandial glycemic load. Amaranthus leaves juice potently mitigated glucose-induced postprandial glycemic load and also reduced hemoglobin glycation induced by glucose in vitro. Conclusions: This investigation finds that juice of leafy vegetables is potent source of biological antioxidants. In addition, juice of raphanus, ajwain and sowa leaves possess capacity to mitigate starch induced postprandial glycemic burden and amaranthus leaves’ juice can reduce glucose induced postprandial glycemic excursion.

Single subcutaneous administration of RGDK-lipopeptide: rhPDGF-B gene complex heals wounds in streptozotocin-induced diabetic rats

Development of effective therapeutics for chronic wounds remains a formidable clinical challenge. Deficiency of growth factors is of paramount importance among the multitude of factors contributing to the pathogenesis of diabetic wounds. Clinical interest has been witnessed in the past for exogenous applications of platelet derived growth factor B (PDGF-B) in chronic nonhealing wounds. However, accomplishing even modest favorable clinical effects in such topical applications requires large and repeated doses of PDGF-B proteins. Chronic wounds are being increasingly circumvented by gene therapy approach and to this end, cationic liposomes are emerging as promising nonviral carriers for delivering various growth factors encoding therapeutic genes to wound beds. However, as in case of topical application of growth factors, all the prior studies on the use of cationic liposomes in nonviral gene therapy of wounds involved repeated injections of cationic liposome:cDNA complexes over several weeks for ensuring complete wound healing. Herein, we show that a single subcutaneous administration of an electrostatic complex of rhPDGF-B plasmid, integrin receptor selective RGDK-lipopeptide 1 and cholesterol (as auxiliary lipid) is capable of healing wounds in streptozotocin-induced diabetic Sprague-Dawley rats (as model of chronic wounds). Western blot analysis revealed significant expression of rhPDGF-B in mouse fibroblast cells transfected with RGDK-lipopeptide 1:rhPDGF-B lipoplex. The transfection efficiencies of the RGDK-lipopeptide 1 in mouse and human fibroblast cells preincubated with various monoclonal anti-integrin receptor antibodies support the notion that the cellular uptake of the RGDK-lipopeptide 1:DNA complexes in fibroblast cells is likely to be selectively mediated by alpha5beta1 integrin receptors. Findings in the histopathological stainings using both hematoxylin and eosin (H & E) as well as Massons Trichrome staining revealed a significantly higher degree of epithelization, keratization, fibrocollagenation and blood vessel formation in rats treated with RGDK-lipopeptide 1:rhPDGF compared to those in rats treated with vehicle alone.

Free radical scavenging, α-glucosidase inhibitory and anti-inflammatory constituents from Indian sedges, Cyperus scariosus R.Br and Cyperus rotundus L.

Background: Cyperus scariosus R. Br and Cyperus rotundus L are widely used in ayurvedic preparation for the treatment of diabetes and other diseases. The early literature ,so far, does not indicate the presence of any bioactive principle isolated from these plants. Objective: To identify free radical scavenging, anti-diabetic and anti- inflammatory principles from these two species. Materials and Methods: The bioassay guided fractionation and isolation of active constituents was done by chromatographic techniques. They also evaluated their anti-oxidant activity by DPPH and ABTS. The anti-diabetic activity was screened by α- glucosidase and α- amylase assays.Also, the further evaluation of in vitro anti-inflammatory activity using THP-1 monocytic cells and in vivo anti- inflammatory activity, was confirmed by carrageenan induced rat paw edema as model. Results: The activity guided isolation led to isolation of twelve compounds Which are: Stigmasterol [1] , β- sitosterol [2] , Lupeol [3] , Gallic acid [4] , Quercetin [5] , β- amyrin [6] , Oleanolic acid [7] , β- amyrin acetate [8] , 4- hydroxyl butyl cinnamate [9] , 4- hydroxyl cinnamic acid [10] , Caffeic acid, [11] and Kaempferol [12] respectively. Among the isolates, the compounds 4 and 5 displayed potent radical scavenging activity with an IC 50 values of 0.43 and 0.067 ΅g/ml. The compounds 4, 5 and 10 showed significant anti-diabetic activities. while lupeol [3] showed potent IL-1 β activity inhibition in THP-1 monocytic cells and also displayed significant (p<0.0025) in vivo anti-inflammatory activity. Conclusion: Inbrief, we isolated twelve compounds from both the species. Collectively, our results suggested that aromatic compounds showed good anti-oxidant and anti-diabetic activities. Abbreviations used: DPPH: 2,2- Diphenyl-1-1-picryl hydrazyl, ABTS: 2,2- Azinobis-3-ethylbenzo thiazoline-6-sulfonic acid, THP-1: Human leukaemia monocytic cell line, IL-1β: Interleukin-1β, IC 50 - Inhibitory concentration 50%.

Combating Established Mouse Glioblastoma through Nicotinylated-Liposomes-Mediated Targeted Chemotherapy in Combination with Dendritic-Cell-Based Genetic Immunization

Accomplishing significantly enhanced overall survivability (OS) remains a formidable challenge in combating glioblastoma. The presence of the blood–brain barrier acts as the major biological barrier in delivering drugs to the brain. Herein, liposomal formulations of two novel nicotinylated amphiphiles are reported for targeting potent anticancer drugs to orthotopic mouse glioblastoma. It is shown that intravenous administration of the potent signal transducer and activator of transcription 3 (STAT3) inhibitor (WP‐1066)‐loaded liposomes of nicotinylated amphiphiles in combination with in vivo dendritic cell (DC)‐targeted subcutaneous genetic immunization (using tyrosinase‐related protein‐2 encoded DNA vaccine) markedly enhances the OS of orthotopic glioblastoma‐bearing mice (by >500% compared to the OS for the control group). Notably, the overall survival benefits in orthotopic‐brain‐tumor‐bearing mice treated with only targeted chemotherapy or with only in vivo DC‐targeted genetic immunization are found to be significantly less. The presently described simple approach avoids the need of isolation of any autologous immune cells. In summary, the preclinical findings described herein open the door for combating glioblastoma in humans through harnessing synergistic effects of targeted chemotherapy and in vivo DC‐targeted genetic immunization.

Synthesis of some novel orsellinates and lecanoric acid related depsides as α-glucosidase inhibitors

Abstract Sixteen novel orsellinic esters (6a-l, 7a-d) along with four lecanoric acid related depsides (3a-c, 4) were synthesized and confirmed their structures by spectroscopic data (1H, 13C & HRMS). The synthesized compounds were evaluated for their in vitro α-glucosidase (Saccharomyces cerevisiae) inhibitory potential. Among the tested compounds, 3c (IC50: 140.9 μM) and 6c (IC50: 203.9 μM) displayed potent α-glucosidase inhibitory activity and found more active than the standard drug acarbose (IC50: 686.6 μM). Both the test compounds were subjected to in vivo antihyperglycemic activity using sucrose loaded model in Wistar rats and found compound 3c exhibited significant reduction in glucose levels.