Piya Paul

Antidiabetic, antihyperlipidemic and antioxidant effects of the flavonoid rich fraction of Pilea microphylla (L.) in high fat diet/streptozotocin-induced diabetes in mice.

The present study describes the antidiabetic effect of the flavonoid rich fraction of Pilea microphylla (PM1). HPLC characterization of PM1 revealed the presence of polyphenols viz., chlorogenic acid, rutin, luteolin-7-O-glucoside, isorhoifolin, apigenin-7-O-glucoside, and quercetin. PM1 inhibited dipeptidyl peptidase IV (DPP-IV) in vitro with an IC(50) of 520.4±15.4 μg/ml. PM1, at doses of 300, 600 and 900 mg/kg i.p., also produced dose-dependent mean percent reductions of 9.9, 30.6 and 41.0 in glucose excursion (AUC(0-120 min)) respectively in lean mice. However, even the highest dose of PM1 did not alter normoglycemic condition. PM1 at dose of 100 mg/kg/day, i.p. for 28 days produced significant (p<0.05) reduction in body weight, plasma glucose (PG), triglycerides (TG) and total cholesterol (TC) content in high-fat streptozotocin-induced diabetic mice. PM1 also improved oral glucose tolerance significantly (p<0.05) with mean percentage reduction of 48.0% in glucose excursion (AUC(0-120 min)) and significantly (p<0.05) enhanced the endogenous antioxidant status in mice liver compared to diabetic control. PM1 preserved islet architecture and prevented hypertrophy of hepatocytes as evident from the histopathology of pancreas and liver. PM1 did not show any detectable hematological toxicity at therapeutic doses. In conclusion, PM1 exhibits antidiabetic effect possibly by inhibiting DPP-IV and improving antioxidant levels in high fat diet/streptozotocin (HFD/STZ) diabetic mice.

Vasorelaxant and antihypertensive effect of Cocos nucifera Linn. endocarp on isolated rat thoracic aorta and DOCA salt-induced hypertensive rats

ETHNOPHARMACOLOGICAL RELEVANCE The fruits of Cocos nucifera Linn. (Arecaceae) have long been used in traditional medicine for the treatment of cardio-metabolic disorders. AIM OF THE STUDY To evaluate the ethanolic extract of Cocos nucifera Linn. endocarp (CNE) for its vasorelaxant activity on isolated rat aortic rings and antihypertensive effects in deoxycorticosterone acetate (DOCA) salt-induced hypertensive rats. MATERIALS AND METHODS Cocos nucifera Linn. endocarp was extracted with ethanol and characterized by HPLC. CNE was examined for its in vitro vascular relaxant effects in isolated norepinephrine, phenylephrine or potassium chloride pre-contracted aortic rings (both intact endothelium and denuded). In vivo anti-hypertensive studies were conducted in DOCA salt-induced uninephrectomized male Wistar rats. RESULTS Removal of endothelium or pretreatment of aortic rings (intact endothelium) with l-NNA (10μM) or ODQ (10 μM) followed by addition of contractile agonists prior to CNE significantly blocked the CNE-induced relaxation. Indomethacin (10μM) and atropine (1 μM) partially blocked the relaxation, whereas glibenclamide (10 μM) did not alter it. CNE significantly reduced the mean systolic blood pressure in DOCA salt-induced hypertensive rats (from 185.3 ± 4.7 mmHg to 145.6±6.1 mmHg). The activities observed were supported by the polyphenols, viz. chlorogenic acid, vanillic acid and ferulic acid identified in the extract. CONCLUSIONS These findings reveal that the vasorelaxant and antihypertensive effects of CNE, through nitric oxide production in a concentration and endothelium-dependent manner, is due to direct activation of nitric oxide/guanylate cyclase pathway, stimulation of muscarinic receptors and/or via cyclooxygenase pathway.

Normal and delayed wound healing is improved by sesamol, an active constituent of Sesamum indicum (L.) in albino rats

UNLABELLED ETHNO-PHARMACOLOGICAL RELEVANCE: The seeds of Sesamum indicum Linn. (Pedaliaceae) has been used traditionally for the treatment of wounds in Buldhana district of Maharashtra state. Sesamol is the main anti-oxidative constituent contained mainly in the processed sesame seed oil which has not been explored scientifically for its wound healing activity. AIM OF THE STUDY To investigate the influence of sesamol (SM) on wound repair, both in normal and dexamethasone (DM) delayed healing processes in albino rats. MATERIALS AND METHODS Incision, excision and dead space wounds were inflicted on albino rats (180-220 g) of either sex, under ketamine anaesthesia. Group I served as control, group II received SM 50 mg/kg i.p., group III was treated with dexamethasone (DM) i.m. (0.17 mg/kg) and SM+DM was given to group IV. The tensile strength, wound contraction, hydroxyproline, lysyl oxidase and total RNA and DNA levels (in granulation tissue) were measured. RESULTS The tensile strength significantly (p<0.05) increased with SM at 471.40±14.66 g when compared to control at 300.60±9.16 g in normal and DM suppressed healing. No significant change was observed in duration of wound contraction and lysyl oxidase when compared to control at 2.98±0.10 mg. SM treated rats showed a significant (p<0.05) rise in hydroxyproline levels at 6.45±0.45 mg when compared to control at 1.75±0.20 mg. CONCLUSION These results indicate that sesamol could be a promising drug in normal as well as delayed wound healing processes.

Sesamol prevents doxorubicin-induced oxidative damage and toxicity on H9c2 cardiomyoblasts

Exposure to toxicants like doxorubicin (Dox) damages cellular components by generating reactive oxygen species (ROS). This can be attenuated using free radical scavengers and/or antioxidants.

Polyphenolic fraction of Pilea microphylla (L.) protects Chinese hamster lung fibroblasts against γ-radiation-induced cytotoxicity and genotoxicity

Present study was designed to compare cytoprotective and antigenotoxic activity of the polyphenolic fraction of Pilea microphylla (PM1) with that of its active polyphenolic constituents against γ-radiation in V79 cells. PM1 was standardized with respect to the polyphenols present by RP-HPLC. It was evaluated for its free radical scavenging potential using Fenton reaction-induced DNA damage and lipid peroxidation. Further, PM1 was subjected against γ-radiation-induced cytotoxicity and genotoxicity in V79 cells. PM1 significantly reduced free radical-mediated calf thymus DNA damage and lipid peroxidation. Among the concentrations tested (12.5, 25 and 50 μg/ml) for radioprotection, PM1 at 25 μg/ml exhibited maximum protection. Further, when compared with constituent polyphenols viz., rutin, quercetin and chlorogenic acid (concentrations equivalent to that present in PM1-25 μg/ml), a combination of polyphenols was found most effective in preventing γ-radiation-induced cytotoxicity and genotoxicity. To conclude, radioprotection is possibly a synergistic effect of the phytochemicals present in the herbal extract, rather than any single component.

Zero-dimensional modelling of a producer gas-based reciprocating engine

Abstract A zero-dimensional modelling study has been conducted using wrinkled flame theory for flame propagation to understand the in-cylinder pressure behaviour with time in a reciprocating internal combustion engine. These are compared with experiments conducted on the engine operated on biomass derived from producer gas and air mixture. The required inputs on the laminar burning velocity and turbulence parameters are obtained from separate studies. The data related to laminar burning velocity for producer gas and air mixture at thermodynamic conditions typical of unburned mixture in an engine cylinder were obtained from one-dimensional flame calculations. The turbulence parameters were obtained by conducting a three-dimensional computational fluid dynamics study on a bowl-in-piston geometry to simulate motored or non-firing conditions. The above mentioned data were used in the zero-dimensional model to make pressure-time (p-θ) computation over the complete engine cycle, for a range of test cases at varying compression ratio (CR) and ignition timing. The computational results matched reasonably well with experimental p-θ curves at advanced ignition timing at all CRs. The error in computed indicated power (IP) at advanced ignition setting (18°-27° CA) is around 3–4 per cent for CR = 17.0 and 11.5, and between 6 and 9 per cent for CR = 13.5. However, at less advanced ignition setting, the error in computed IP is larger and this is attributed to enhanced fluid dynamic effect due to reverse squish effect. And, whenever major part of the combustion occurred during this period, the deviation in the computed result appeared to be larger. This model has also been used to predict output of a commercially available producer gas engine of 60 kW. The optimum ignition timing on this particular engine was experimentally found to be 22°-24° before top centre. The zero-dimensional model has been used in a predictive mode and results compared with brake power under wide throttle open condition.

Pro-healing effects of morin, a natural antioxidant, on normal and dexamethasone-impaired wounds.

Abstract Background: The aim of the study was to investigate the effects of morin on skin breaking strength, hydroxyproline, lysyl oxidase, DNA and RNA content of experimentally inflicted wounds in rats. Methods: This study was performed on albino rats of either sex at the Central Animal Research Facility (CARF), Manipal University. Results: Morin showed significant wound contraction on day 7 as compared to control with mean closure of 47.44±6.07% in excision wound model. Granulation tissue breaking strength was significantly increased (p<0.05) in the morin treated group with 180.2±7.94 g when compared to control at 151.2±6.99 g. There was a significant increase in hydroxyproline content with the morin treated group when compared to control with 3.41±0.33 μg/mg of granulation tissue. Similarly, the wound parameters were improved with the morin treated group in dexamethasone delayed healing. Conclusions: Our results suggest that morin treatment accelerates the healing process delayed by concurrent use of steroids.