Gopalan Kutty Nampurath

Petroleum ether extract of Cissus quadrangularis (Linn.) enhances bone marrow mesenchymal stem cell proliferation and facilitates osteoblastogenesis.

OBJECTIVE To evaluate the effects of the petroleum ether extract of Cissus quadrangularis on the proliferation rate of bone marrow mesenchymal stem cells, the differentiation of marrow mesenchymal stem cells into osteoblasts (osteoblastogenesis) and extracellular matrix calcification. This study also aimed to determine the additive effect of osteogenic media and Cissus quadrangularis on proliferation, differentiation and calcification. METHODS MSCs were cultured in media with or without Cissus quadrangularis for 4 weeks and were then stained for alkaline phosphatase. Extracellular matrix calcification was confirmed by Von Kossa staining. marrow mesenchymal stem cells cultures in control media and osteogenic media supplemented with Cissus quadrangularis extract (100, 200, 300 μg/mL) were also subjected to a cell proliferation assay (MTT). RESULTS Treatment with 100, 200 or 300 μg/mL petroleum ether extract of Cissus quadrangularis enhanced the differentiation of marrow mesenchymal stem cells into ALP-positive osteoblasts and increased extracellular matrix calcification. Treatment with 300 μg/mL petroleum ether extract of Cissus quadrangularis also enhanced the proliferation rate of the marrow mesenchymal stem cells. Cells grown in osteogenic media containing Cissus quadrangularis exhibited higher proliferation, differentiation and calcification rates than did control cells. CONCLUSION The results suggest that Cissus quadrangularis stimulates osteoblastogenesis and can be used as preventive/ alternative natural medicine for bone diseases such as osteoporosis.

Evidence-based assessment of antiosteoporotic activity of petroleum-ether extract of Cissus quadrangularis Linn. on ovariectomy-induced osteoporosis

The increasing incidence of postmenopausal osteoporosis and its related fractures have become global health issues in the recent days. Postmenopausal osteoporosis is the most frequent metabolic bone disease; it is characterized by a rapid loss of mineralized bone tissue. Hormone replacement therapy has proven efficacious in preventing bone loss but not desirable to many women due to its side-effects. Therefore we are in need to search the natural compounds for a treatment of postmenopausal symptoms in women with no toxic effects. In the present study, we have evaluated the effect of petroleum-ether extract of Cissus quadrangularis Linn. (CQ), a plant used in folk medicine, on an osteoporotic rat model developed by ovariectomy. In this experiment, healthy female Wistar rats were divided into four groups of six animals each. Group 1 was sham operated. All the remaining groups were ovariectomized. Group 2 was fed with an equivolume of saline and served as ovariectomized control (OVX). Groups 3 and 4 were orally treated with raloxifene (5.4 mg/kg) and petroleum-ether extract of CQ (500 mg/kg), respectively, for 3 months. The findings were assessed on the basis of animal weight, morphology of femur, and histochemical localization of alkaline phosphatase (ALP) (an osteoblastic marker) and tartrate-resistant acid phosphatase (TRAP) (an osteoclastic marker) in upper end of femur. The study revealed for the first time that the petroleum-ether extract of CQ reduced bone loss, as evidenced by the weight gain in femur, and also reduced the osteoclastic activity there by facilitating bone formation when compared to the OVX group. The osteoclastic activity was confirmed by TRAP staining, and the bone formation was assessed by ALP staining in the femur sections. The color intensity of TRAP and ALP enzymes from the images were evaluated by image analysis software developed locally. The effect of CQ was found to be effective on both enzymes, and it might be a potential candidate for prevention and treatment of postmenopausal osteoporosis. The biological activity of CQ on bone may be attributed to the phytogenic steroids present in it.

Vasorelaxant effect in rat aortic rings through calcium channel blockage: a preliminary in vitro assessment of a 1,3,4-oxadiazole derivative.

The study was undertaken on the basis of several reports in the literature that relaxation of vascular smooth muscles is a good treatment strategy in hypertension, angina and other cardiovascular disorders. Oxadiazoles have been reported to have effect on vascular smooth muscles and calcium influx. The goals of our current in vitro study were to investigate the effect of a 1,3,4-oxadiazole derivative on vascular smooth muscles in rat aorta, and to elucidate the associated signaling pathway. NOX-1 induced a relaxation of vascular smooth muscles in both endothelium intact and denuded rat aortic rings precontracted with norepinephrine or phenylephrine or KCl. NOX-1 also significantly antagonized cumulative dose-response effect of norepinephrine, phenylephrine, KCl or calcium with reduction in submaximal contractions. Verapamil, an L-type of calcium channel blocker, effectively attenuated phenylephrine and calcium induced contractions in aortic rings. Incubation with NOX-1 and verapamil did not significantly alter the dose-response curve of phenylephrine or calcium compared to verapamil treatment alone indicating L-type Ca2+ channel blockage leads to loss of NOX-1 activity. Hence it can be concluded NOX-1 exhibited vasorelaxant action by inhibiting calcium influx from extracellular space to intracellular space through L-type of calcium channels.

Antidiabetic effect through islet cell protection in streptozotocin diabetes: a preliminary assessment of two thiazolidin-4-ones in Swiss albino mice.

This study was undertaken on the basis of several reports in the literature that pancreatic beta cells are capable of replication/regeneration and also being afforded protection against damage induced by streptozotocin. Nicotinamide was reported to give protection against streptozotocin-induced damage in rats. In the present study, two thiazolidine-4-ones with nicotinamide substitution were administered to Swiss albino mice with streptozotocin diabetes for 15 days. Concurrently, one group received nicotinic acid. Both the test compounds reversed the hyperglycaemia diabetic mice. Damage to pancreatic islets was also reduced in these groups compared to diabetic control and nicotinic acid treated groups. Since these compounds have been earlier found have antioxidant activity, one of the possible mechanisms of action could be by reducing oxidative stress in pancreas. Further, possibly by releasing nicotinamide in vivo, the molecules could have contributed to the NAD pool in pancreas and afforded protection. It is concluded that the test compounds have potential to be developed for multiple beneficial action in conditions like metabolic syndrome.

Modulatory Role of Simvastatin against Aluminium Chloride-Induced Behavioural and Biochemical Changes in Rats

Objectives. Aluminium, a neurotoxic agent in humans, has been implicated in the pathogenesis of neurodegenerative disorders. In this study, we examined the behavioral and biochemical effects of aluminium in rats with special emphasis on memory centres, namely, hippocampus and frontal cortex. Further, the effect of simvastatin treatment on aluminium intoxication was evaluated. Methods. Rats were exposed to aluminium chloride (AlCl3) for 60 days. Simvastatin (10 mg/kg/p.o.) and rivastigmine (1 mg/kg/p.o.) were administered daily prior to AlCl3. Behavioral parameters were assessed using Morris water maze test and actophotometer followed by biochemical investigations, namely, acetylcholinesterase (AChE) activity, TNF-α level, antioxidant enzymes (GSH, catalase), lipid peroxidation, and nitrite level in hippocampus and frontal cortex. Triglycerides, total cholesterol, LDL, and HDL levels in serum were also determined. Key Findings. Simvastatin treatment improved cognitive function and locomotor activity in rats. Simvastatin reversed hyperlipidemia and significantly rectified the deleterious effect of AlCl3 on AChE activity. Further, in hippocampus and frontal cortex, aluminium-induced elevation in nitrite and TNF-α and reduction in antioxidant enzymes were inhibited by simvastatin. Conclusion. To conclude, the present study suggests that simvastatin per se protects the neurons in hippocampus and frontal cortex from AlCl3, an environmental toxin.

Insulin Blocks Glutamate-Induced Neurotoxicity in Differentiated SH-SY5Y Neuronal Cells

Insulin is a cytokine which promotes cell growth. Recently, a few published reports on insulin in different cell lines support the antiapoptotic effect of insulin. But the reports fail to explain the role of insulin in modulating glutamate-mediated neuronal cell death through excitotoxicity. Thus, we examined the neuroprotective effect of insulin on glutamate-induced toxicity on differentiated SH-SY5Y neuronal cells. Changes in cell viability were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) based assay, while apoptotic damage was detected by acridine orange/ethidium bromide and Hoechst staining. Intracellular reactive oxygen species (ROS) accumulation and morphological alterations were also measured. Treatment with glutamate induced apoptosis, elevated ROS levels and caused damage to neurons. Insulin was able to attenuate the glutamate-induced excitotoxic damage to neuronal cells.

A possible correlation between the correction of endothelial dysfunction and normalization of high blood pressure levels by 1,3,4-oxadiazole derivative, an L-type Ca2+ channel blocker in deoxycorticosterone acetate and NG-nitro-l-arginine hypertensive rats

We have previously demonstrated the vasorelaxant activity of 1,3,4-oxadiazole derivative (NOX-1) through L-type Ca2+ channel blockage. In the present study, we investigated whether the correction of endothelial dysfunction is dependent on the normalization of high blood pressure levels by 1,3,4-oxadiazole derivative (NOX-1) in deoxycorticosterone acetate (DOCA-salt) and N(G)-nitro-l-arginine (L-NNA) hypertensive rats. In DOCA-salt and L-NNA hypertensive rats, the mean systolic blood pressure (MSBB) was 185.3+/-4.7 and 170.2+/-4.1 mmHg, whereas after administration of NOX-1 to hypertensive rats, MSBB was 127.8+/-4.5 and 120.2+/-5.1 mmHg, respectively. To study the endothelial dysfunction, concentration-response curves of norepinephrine (NE) and acetylcholine (Ach) were constructed in rat aortic rings isolated from normotensive, hypertensive (DOCA and L-NNA) and NOX-1 treated rats. NE-induced contractions and Ach-induced relaxations were significantly (p<0.05) decreased and increased, respectively in the aorta of NOX-1 treated rats. Vasorelaxant activity of NOX-1 was not abolished by pretreatment of aortic rings with L-NNA, 1H-[1,2,4] oxadiazolo [4,3-A] quinoxalin-1-one (ODQ), indomethacin or glibenclamide. The results suggest that the endothelial dysfunction can be corrected by the L-type Ca2+ channel blocker with endothelium-independent action and that is dependent on the normalization of high blood pressure levels. The antihypertensive and vasorelaxant effects of NOX-1 are mainly endothelial-independent and it can be used to treat hypertension, a state associated with endothelial dysfunction.

Sesamol, a lipid lowering agent, ameliorates aluminium chloride induced behavioral and biochemical alterations in rats

Background: Sesame oil from the seeds of Sesamum indicum Linn. (Pedaliaceae) has been used traditionally in Indian medical practice of Ayurveda in the treatment of central nervous system disorders and insomnia. A few published reports favor the anti-dementia effect of sesamol (SML), an active constituent of sesame oil. Objective: Thus, the present study was aimed to explore the anti-dementia effect and possible mechanism (s) of SML in aluminium chloride (AlCl3)-induced cognitive dysfunction model in rodents with special emphasis on memory centers viz., hippocampus and frontal cortex. Methods: Male Wistar rats were exposed to AlCl3 (175 mg/kg p.o.) for 60 days. SML (10 and 20 mg/kg) and rivastigmine (1 mg/kg) were administered orally 45 min before administration of AlCl3 for 60 days. Spatial memory was assessed using Morris water maze test. After 60 days of treatment animals were sacrificed, hippocampus and frontal cortex were collected and analyzed for acetylcholinesterase (AChE) activity, tumor necrosis factor (TNF-α) level, antioxidant enzymes (Glutathione, catalase), lipid peroxidation, and nitrite level. The circulating triglycerides, total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) levels were also analyzed. Results: SML significantly prevented behavioral impairments in aluminium-exposed rats. Treatment with SML reversed the increased cholesterol, triglycerides and LDL while raised the HDL levels. SML significantly corrected the effect of AlCl3 on AChE activity. Further, SML reversed the elevated nitric oxide, TNF-α and reduced antioxidant enzymes in hippocampus and frontal cortex. Conclusion: The present study suggests the neuro-protection by SML against cognitive dysfunction induced by environmental toxin (AlCl3) in hippocampus and frontal cortex.

Remedial effects of novel 2,3-disubstituted thiazolidin-4-ones in chemical mediated inflammation.

Three thiazolidin-4-one derivatives were synthesized, purified and characterized by chromatographic and spectroscopic methods. In the in vitro assays, these compounds inhibited reactive oxygen species (ROS), nitrite and cytokine generation in RAW 264.7 murine macrophages and whole blood. These derivatives attenuated carrageenan-induced acute inflammation in rats. The most effective compound 4C possessed identical anti-inflammatory action at two doses (50 and 100 mg/kg). Further, the effect of compound 4C on locally induced inflammatory mediators was investigated in carrageenan-induced air pouch inflammation in rats. In this model, compound 4C inhibited the cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-6 (systemic and local). Additionally, compound 4C was able to reduce locally elevated prostaglandin-E₂ (PGE₂). Inhibition of leukocyte infiltration by compound 4C was correlated with reduced locally released myeloperoxidase (MPO). To conclude, compound 4C corrected the inflammatory condition by negative effect on cytokine (TNF-α, IL-6) network and prostaglandin-E₂ generation.

Novel 2,5-disubstituted-1,3,4-oxadiazoles as anti-inflammatory drugs

Objective: 1,3,4-oxadiazole ring is a versatile moiety with a wide range of pharmacological properties. The present work deals with the synthesis and evaluation of the anti-inflammatory activity of two novel 2,5-disubstituted-1,3,4-oxadiazoles (OSD and OPD). Materials and Methods: Carrageenan-induced rat hind paw edema was employed as an acute model of inflammation. For evaluating sub-acute anti-inflammatory activity, carrageenan-induced inflammation in rat air pouch was employed. Complete Freunds adjuvant-induced arthritis in rats was used as a model of chronic inflammation. To evaluate in vitro anti-inflammatory activity, lipopolysaccharide (LPS)-stimulated RAW264.7 cells were used. Results: OSD (100 mg/kg) reduced carrageen-induced paw edema by 60%, and OPD (100 mg/kg) produced a modest 32.5% reduction. OSD also reduced leukocyte influx and myeloperoxidase in carrageenan-induced rat air pouch model. In complete Freunds adjuvant-induced arthritis model, both OSD and OPD (200 mg/kg for 14 days) reduced paw edema and NO levels. In LPS-stimulated RAW264.7 cells, OSD and OPD inhibited formation of nitric oxide and reactive oxygen species, with OPD showing a better activity in comparison to OSD. Conclusions: OSD was the better of the two compounds in in vivo models of inflammation. The o-phenol substitution at position 2 of oxadiazole ring in OSD may be responsible for its better in vivo anti-inflammatory activity. The ability of the compounds to inhibit LPS-induced pro-inflammatory mediator release suggests an anti-inflammatory mechanism targeting LPS-TLR4-NF-κB signalling pathway, which needs to be explored in detail. The disparate efficacy in vitro and in vivo also requires in-depth evaluation of the pharmacokinetics of these novel oxadiazoles.