Vishnu N. Thakare

Silymarin improves the behavioural, biochemical and histoarchitecture alterations in focal ischemic rats: A comparative evaluation with piracetam and protocatachuic acid

Comparative neuroprotective potential of silymarin, piracetam and protocatechuic acid ethyl ester (PCA) was evaluated in focal ischemic rats. Various pharmacological, biochemical (lipid peroxidation, reduced glutathione, catalase, nitrite content, brain water content) and behavioural (memory impairment, motor control, neurological score) including infarct size and histopathological alterations were evaluated. Silymarin (200mg/kg) and PCA treatment significantly improved behavioural, biochemical and histopathological changes, and reduced water content and infarct size. However, piracetam only improved behavioural and histopathological changes, reduced water content and infarct size. The findings indicate that silymarin exhibits neuroprotective activity better than PCA and piracetam in focal ischemia/reperfusion reflected by its better restoration of behavioural and antioxidant profile.

Design, synthesis, characterization and anti-inflammatory evaluation of novel pyrazole amalgamated flavones.

A series of novel pyrazole amalgamated flavones has been designed and synthesized from 1-methyl-5-(2,4,6-trimethoxy-phenyl)-1H-pyrazole 6. The structures of regioisomers 6 and 7 were resolved by 2D (1)H-(1)H COSY, (1)H-(13)C HSQC and (1)H-(13)C HMBC experiments. The newly synthesized compounds were tested for their in vitro COX inhibition and in vivo carrageenan induced hind paw edema in rats and acetic acid induced vascular permeability in mice. Although the compounds have inhibitory profile against both COX-1 and COX-2, some of the compounds are found to be selective against COX-2, supported by inhibition of paw edema and vascular permeability. Docking studies were also carried out to determine the structural features which sway the anti-inflammatory activity of the tested compounds. The keto and phenolic -OH are major factors that are prominently involved in interaction with COX-2 active site.

Therapeutic potential of curcumin in experimentally induced allergic rhinitis in guinea pigs

In the present experiments, the possible role of curcumin in ovalbumin induced allergic rhinitis in guinea pig model was investigated. Various allergic rhinitis symptoms viz sneezing, rubbing frequencies, lacrimation and nasal congestion at various humidity conditions as well as on repeated sensitization were studied. The biochemical changes like serum IgE, IL-4 and nitric oxide (NO) in nasal lavage and eosinophil peroxidase activity in nasal homogenates were determined in allergic rhinitis. Curcumin treatment significantly reduced the symptoms (sneezing, rubbing frequencies, lacrimation and nasal congestion) and improved the histopathological alterations (reduction in inflammatory cells infiltration) of nasal mucosa in allergic rhinitis. Furthermore, curcumin treatment prevented significantly elevation of serum IgE, IL-4, NO in nasal lavage and eosinophil peroxidase in nasal homogenate. In the present experimental findings, we suggest that curcumin is a promising anti-allergic agent that may be useful in the clinical management of allergic rhinitis.

Amelioration of cognitive, motor and endogenous defense functions with silymarin, piracetam and protocatechuic acid in the cerebral global ischemic rat model

AIMSnThe neuroprotective activities of silymarin, piracetam and protocatechuic acid ethyl ester (PCA) on cerebral global ischemic/reperfusion were evaluated in a rat model.nnnMAIN METHODSnA midline ventral incision was made in the throat region. The right and left common carotid arteries were located and a bilateral common carotid artery occlusion (BCCAO) was performed for 30min using atraumatic clamps followed by a 24h period of reperfusion. Neurological/behavioral functions (cognitive and motor), endogenous defense systems (lipid peroxidation, glutathione, catalase, and superoxide dismutase), reduced water content and infarct size and histopathological alterations were then studied.nnnKEY FINDINGSnSilymarin and PCA treatments significantly improved cognitive, motor and endogenous defense functions, histopathological alterations, and, reduced both water content and infarct size compared to the vehicle-treated ischemic control group. Piracetam treatment improved neurological and histopathological alterations, reduced water content and infarct size, but failed to restore/prevent the impaired endogenous defense functions significantly.nnnSIGNIFICANCEnSilymarin showed better neuroprotection than piracetam and PCA in experimentally induced global ischemic/reperfusion and was able to facilitate mnemonic performance.

Potential antidepressant-like activity of silymarin in the acute restraint stress in mice: Modulation of corticosterone and oxidative stress response in cerebral cortex and hippocampus.

BACKGROUNDnSilymarin is a polyphenolic flavanoid of Silybum marianum, elicited neuroprotection and antidepressant like activity in stressed model. It was found to increase 5-hydroxytryptamine (5-HT) levels in the cortex and dopamine (DA) and norepinephrine (NE) in the cerebellum in normal mice. The aim of the present study was to investigate the potential antidepressant-like activity of silymarin in the acute restraint stress (ARS) in mice.nnnMETHODSnThe ARS was induced by immobilizing the mice for a period of 7h using rodent restraint device preventing them for any physical movement. One hour prior to ARS, silymarin was administered at doses of 100mg/kg and 200mg/kg per oral to non stressed and ARS mice. Various behavioral parameters like immobility time in force swim test, locomotor activity in open field test, and biochemical alterations, serum corticosterone, 5-HT, DA, NE level, malondialdehyde (MDA), and antioxidant enzymes (GSH, CAT and SOD) in hippocampus and cerebral cortex in non stressed and ARS subjected mice were investigated.nnnRESULTSnExperimental findings reveals mice subjected to ARS exhibited significant increase immobility time, serum corticosterone, MDA formation and impaired SOD and CAT activities in hippocampus and cerebral cortex as compared to non stressed mice. Silymarin treatment (100mg/kg and 200mg/kg) significantly attenuated immobility time, corticosterone and restored the antioxidant enzymes after ARS.nnnCONCLUSIONnThe present experimental findings indicate that silymarin exhibits antidepressant like activity probably either through alleviating oxidative stress by modulation of corticosterone response, and antioxidant defense system in hippocampus and cerebral cortex in ARS mice.

Silymarin ameliorates experimentally induced depressive like behavior in rats: Involvement of hippocampal BDNF signaling, inflammatory cytokines and oxidative stress response

Silymarin is a polyphenolic flavonoid of Silybum marianum, exhibited neuroprotection and antidepressant like activity in acute restraint stressed mice. The main objective of the present study is to investigate possible antidepressant like activity of silymarin in experimentally induced depressive behavior in rats. The depressive behaviors were induced in rats by olfactory bulbectomized (OBX) technique. Wistar rats were administered with silymarin at a dose of 100mg/kg and 200mg/kg, by per oral in OBX and sham operated rats. Behavioral (ambulatory and rearing activity and immobility time), neurochemical [serotonin (5-HT), dopamine (DA), norepinephrine (NE) and brain derived neurotrophic factor (BDNF) level], biochemical (MDA formation, IL-6, TNF-α and antioxidants) changes in hippocampus and cerebral cortex along with serum corticosterone were investigated. Rats subjected to OBX elicited significant increase in immobility time, ambulatory and rearing behaviors, reduced BDNF level, 5-HT, DA, NE and antioxidant parameters along with increased serum corticosterone, MDA formation, IL-6, and TNF-α in hippocampus and cerebral cortex compared to sham operated rats. Administration of with silymarin significantly attenuated immobility time, ambulatory and rearing behaviors, serum corticosterone and improved BDNF expression, 5-HT, DA, NE and antioxidant paradigms in cerebral cortex as well as hippocampus. In addition, silymarin attenuated IL-6, and TNF-α significantly in hippocampus and cerebral cortex in OBX rats. Thus, silymarin exhibits anti-depressant-like activity in OBX rats due to alterations in several neurotransmitters, endocrine and immunologic systems, including BDNF, 5-HT, DA, NE, MDA formation, IL-6, and TNF-α in hippocampus and cerebral cortex as well as serum corticosterone.

Therapeutic potential of silymarin in chronic unpredictable mild stress induced depressive-like behavior in mice:

Silymarin, a plant-derived polyphenolic flavonoid of Silybum marianum, elicited significant antidepressant-like activity in an acute restraint stress model of depression. It improved monoamines, mainly 5-hydroxytryptamine (5-HT) levels in the cortex, dopamine (DA) and norepinephrine (NE) in the cerebellum in mice. The present study was undertaken to explore the antidepressant potential of silymarin in chronic unpredictable mild stress (CUMS) induced depressive-like behavior in mice, and to find out its probable mechanism(s) of action, mainly neurogenesis, neuroinflammation, and/or oxidative stress. The mice were subjected to CUMS for 28 days (4 weeks) and administered with silymarin (100 mg/kg and 200 mg/kg), or fluoxetine or vehicle from days 8 to 28 (3 weeks simultaneously). Animals were evaluated for behavioral changes, such as anhedonia by sucrose preference test, behavioral despair by forced swim test, and exploratory behaviors by an open field test. In addition, neurobiochemical alterations, mainly monoamines, 5-HT, NE, DA, neurotrophic factor BDNF, and cytokines, IL-6, TNF-α, oxidant-antioxidant parameters by determining the malondialdehyde formation (an index of lipid peroxidation process), superoxide dismutase (SOD) and catalase (CAT) activity in hippocampus and cerebral cortex along with serum corticosterone were investigated. Our findings reveal that mice subjected to CUMS exhibited lower sucrose preference, increase immobility time without affecting general locomotion of the animals, and reduce BDNF, 5-HT, NE, and DA level, increased serum corticosterone, IL-6 and TNF-α along with an oxidant-antioxidant imbalance in the hippocampus and cerebral cortex. Silymarin significantly reversed the CUMS-induced changes in the hippocampus and cerebral cortex in mice. Thus, the possible mechanism involved in the antidepressant-like activity of silymarin is correlated to the alleviation of monoaminergic, neurogenesis (enhancing 5-HT, NE, and BDNF levels), and attenuation of inflammatory cytokines system and oxidative stress by modulation of corticosterone response, restoration of antioxidant defense system in cerebral cortex and hippocampus.

Design, synthesis, characterization and in vitro and in vivo anti-inflammatory evaluation of novel pyrazole-based chalcones

Abstract A series of novel pyrazole-based chalcones have been designed, synthesized from 1-methyl-5-(2,4,6-trimethoxyphenyl)-1H-pyrazole (6). The structures of regioisomers 6 and 7 were determined by 2D 1H–1H COSY, 1H–13C HSQC and 1H–13C HMBC experiments. The newly synthesized compounds were tested for their inhibitory activity against COX-1 and COX-2 using an in vitro cyclooxygenase (COX) inhibition assay. Moreover, they were investigated in vivo for their anti-inflammatory activities using carrageenan-induced rat paw edema model for acute inflammation and cotton pellet-induced granuloma model for chronic inflammation. All the synthesized compounds showed potential to demonstrate anti-inflammatory activities, of particular interest compounds 10i, 10e, 10f, and 10h were found to be potent anti-inflammatory agents.

Potential targets for the development of novel antidepressants: future perspectives.

Depression is an affective disorder characterized by hallucination, delusion and increased social risk and is estimated to affect approximately 20 % of the population at some point during the lifetime. As per World Health Organization (WHO) it is predicted to be the leading cause of burden of disease by 2030. Effects of currently available antidepressants have explained the monoamine hypothesis of depression, which proposes that impaired release of serotonin, noradrenaline and dopamine, are thought to be responsible for the development of depressive symptoms. However, these drugs are not specific for their action, as they also inhibit other enzymes; this explains the side effects/drug interactions associated with these agents. The present review will familiarize the readers with novel targets being identified for depression which will be certainly beneficial for researcher, academician for the development of drugs for the management of depression and related behavior.

Novel ibuprofen prodrugs with improved pharmacokinetics and non-ulcerogenic potential

In the present study, we evaluated the anti-inflammatory activity with pharmacokinetic, ulcerogenic properties of various synthesized prodrugs of ibuprofen in experimental animals. Prodrugs 2, 6, 9, 10, 12, and 14 were found to possess significant anti-inflammatory activity with almost non-ulcerogenic potential than standard drug ibuprofen 1a in both normal and inflammation-induced rats. Metabolic stability of prodrugs 2, 6, 9, 10, 12, and 14 were also studied in rat liver microsomes and oral bioavailability was determined by estimating area under curve (AUC) and plasma concentration of these prodrugs at various time intervals. The experimental findings elicited higher AUC and plasma concentration at 1 and 2xa0h indicating improved oral bioavailability as compared to parent ibuprofen. These prodrugs are found to have least gastric ulceration with retain anti-inflammatory activity observed in experimental animals. Therefore, present experimental findings demonstrated significant improvement of various pharmacokinetic properties with least ulcerogenic potential of ester prodrugs of ibuprofen an anti-inflammatory agent