Dissolution Rate Enhancement of Repaglinide Using Dietary Fiber as a Promising Carrier.

In present investigation, an innovative attempt has been made to enhance the solubility and dissolution rate of Repaglinide (RPGD) using hydrothermally treated water insoluble dietary bamboo fibers (HVBF) as potential nutraceutical used in the treatment of diabetes mellitus. RPGD was selected as a model drug due to its low aqueous solubility and dissolution rate. Characterization of HVBF demonstrated the outstanding features like high surface area, maximum drug loading and increase dissolution rate and making HVBF as an excellent drug carrier. RHVBF (Repaglinide loaded HVBF) tablets were prepared using direct compression method. Pre and post-compression parameters for blend and tablets were studied and found within acceptable limits. RHVBF and tablet showed significantly improved dissolution rate, when compared with pure crystalline RPGD, physical mixture, RVBF and commercial marketed tablet. This fact was further supported by FT-IR, DSC, XRPD and FESEM studies followed by in-vitro drug release profile. Stability studies showed no changes after exposing to accelerated conditions for a period of 3 months with respect to physical characteristics and in-vitro drug release studies. In a nut shell, it can be concluded that HVBF is a novel, smart and promising carrier for poorly water soluble drugs, when administered orally.

Role of 5-HT2 receptors in diabetes: Swertiamarin seco-iridoid glycoside might be a possible 5-HT2 receptor modulator.

In the present review, we are focusing on modulators of 5-HT2 receptors, swertiamarin and their role in diabetes. These drugs possess both central and peripheral actions in various animal models of depression, diabetes and obesity. Swertiamarin and 5-HT2 antagonist are reported antidepressant, hypolipidemic and beneficial in peripheral vasculopathy. In contrast to this, 5-HT2C selective agonist decreases hyperglycemia, hyperlipidemia and insulin secretogogue by action. Selective serotonin reuptake inhibitors (SSRIs) are known antidepressant having weight gain as an adverse effect. Swertiamarin has similar pharmacological actions as 5-HT2 antagonist and 5-HT2C selective agonist. This warrants that swertiamarin might modulate 5-HT2 receptors rather than affecting the uptake of serotonin. In the light of present investigation, the mechanism of these drugs can correlate the role of central and peripheral 5-HT2 receptors in diabetes.

Oleanolic Acid Prevents Increase in Blood Pressure and Nephrotoxicity in Nitric Oxide Dependent Type of Hypertension in Rats.

BACKGROUND: Recently, we have reported antihypertensive activity of oleanolic acid (OA) in glucocorticoid-induced hypertension with restoration of nitric oxide (NO) level. However, the involvement of NO-releasing action of OA was unclear. OBJECTIVE: To explore antihypertensive activity of OA in N(ω)-nitro-L-arginine methyl ester (L-NAME) hypertensive rats wherein NO is completely blocked, which would allow exploring the possibility of involvement of NO-releasing action of OA. MATERIALS AND METHODS: Five groups of rats were investigated as normal control, L-NAME (40 mg/kg/day), L-NAME + enalapril (15 mg/kg/day), L-NAME + l-arginine (100 mg/kg/day), and L-NAME + OA (60 mg/kg/day) for 4 weeks. The systolic blood pressure, body weight, and heart rate were measured weekly for 4 weeks. Serum nitrate/nitrite (NOx) level, urine electrolytes concentration, cardiac mass index, and serum creatinine level were determined followed by organ histopathology. RESULTS: OA and enalapril delayed the rise in blood pleasure following L-NAME administration. Decreased serum NOx level was not significantly increased with any of the treatment. OA produced a small, though nonsignificant, increase in the NOx level. L-NAME administration did not affect cardiac mass index. There was an increase in serum creatinine upon L-NAME administration which was prevented by OA. Decreased urine volume, urine sodium and potassium were reversed by OA. CONCLUSION: These results suggest that the antihypertensive effect of OA in L-NAME hypertension is due to diuresis and nephroprotection. However, OA has nonsignificantly affected the NO levels.

Effect of Viscum articulatum Burm. (Loranthaceae) in Nω-nitro-L-arginine methyl ester induced hypertension and renal dysfunction.

ETHNOPHARMACOLOGICAL RELEVANCE: Viscum articulatum Burm. is used traditionally in Chinese medicine for treating hypertension. AIM OF THE STUDY: The present study was designed to evaluate the antihypertensive activity of the methanolic extract of Viscum articulatum (MVA) against N(ω)-nitro-L-arginine methyl ester (L-NAME) induced hypertension in rats. MATERIALS AND METHODS: Six groups of rats were investigated for 4 weeks as normal control, L-NAME (40 mg/kg/day), L-NAME+enalapril (15 mg/kg/day), L-NAME+L-arginine (100 mg/kg/day), L-NAME+MVA (200 mg/kg/day) and L-NAME+MVA (400 mg/kg/day) for four weeks. The systolic blood pressure (SBP) and heart rate (HR) were measured weekly throughout the experimental period. The urine electrolytes concentration, cardiac mass index, serum nitrate/nitrite (NO(x)) level, serum creatinine level and lipid profile were determined. RESULTS: Treatment with MVA (200 and 400 mg/kg) or enalapril delayed the rise in SBP produced by administration of L-NAME. None of the treatments had a significant effect on the depression of the serum NO(x) level caused by L-NAME. The serum creatinine and total cholesterol concentrations were elevated upon administration of L-NAME, and this elevation was prevented by MVA co-administration. The urine volume and urine potassium ion level were depressed by L-NAME administration and this effect being inhibited in MVA and enalapril groups. There was no cardiac hypertrophy and HR change after 28 day of L-NAME administration. CONCLUSION: We conclude that MVA may have an antihypertensive effect in the NO deficient type of hypertension, which may be attributed to its diuretic, nephroprotective and hypolipidemic actions.

Amaranthus spinosus Linn. inhibits mast cell-mediated anaphylactic reactions.

The current study characterizes the mechanism by which the Amaranthus spinosus (Amaranthaceae) decreases mast cell-mediated anaphylactic reactions. Anaphylaxis is a typical hypersensitivity Type I reaction, sharing common mechanisms with asthma in its early and late phases. Mast cells are key as effector cells in hypersensitivity Type I reactions. A. spinosus has been traditionally used in the treatment of allergic bronchitis and asthma, but its role in mast cell-mediated anaphylactic reactions has not fully been investigated. This report investigated the potential effects of the ethyl acetate fraction of A. spinosus leaves (EAFAS) against a compound 48/80 (potent secretagogue)-induced systemic anaphylactic shock paradigm in a mouse model. In addition, rat peritoneal mast cells (RPMC) were used in in vitro studies to investigate the effect of EAFAS on compound 48/80-induced peritoneal mast cell degranulation and histamine release. When administration by the oral route-1 h before compound 48/80 injection-EAFAS (at dose from 0.001-1 g/kg) completely inhibited the induced anaphylactic shock. EAFAS at concentrations ranging 0.25-1 mg/ml dose-dependently attenuated rates of mast cell degranulation and histamine release from RPMC that were evoked by compound 48/80. The results of the present investigation indicated that EAFAS stabilizes the mast cell lipid bilayer membrane, thereby preventing the perturbation of membrane and the release of histamine. As a result of these anti-degranulating and anti-histaminic effects, it can be suggested that EAFAS may have a potential use in the prophylaxis and management of anaphylactic reactions.

Oleanolic acid prevents glucocorticoid-induced hypertension in rats.

The present study was designed to evaluate the antihypertensive activity of oleanolic acid isolated from Viscum articulatum, Burm. (Loranthaceae) in glucocorticoid (dexamethasone)-induced hypertension in rats and to propose a probable mechanism of action for this effect. Male Wistar rats (300-350 g) received dexamethasone (20 µg/kg/day s.c.) or saline (vehicle) for 10 days. In a prevention study, the rats received oleanolic acid (60 mg/kg i.p.) for 5 days, followed by dexamethasone or saline for 10 days. During this period the systolic blood pressure and body weight were evaluated on alternate days. At the end of the experiment, the weight of the thymus gland, plasma nitrate/nitrite (nitric oxide metabolites) concentration and cardiac lipid peroxidation value were determined. Oleanolic acid (60 mg/kg i.p.) significantly prevented a rise in the systolic blood pressure and cardiac lipid peroxidation level after administration of dexamethasone (p < 0.01 and p < 0.05, respectively) without showing any significant effect on the dexamethasone-induced change in body and thymus weights. The decrease in concentration of plasma nitrate/nitrite due to dexamethasone was prevented significantly in the group treated with oleanolic acid (p < 0.05). These findings suggest that oleanolic acid (60 mg/kg i.p.) prevents dexamethasone-induced hypertension in rats, which may be attributed to its antioxidant and nitric oxide releasing action.

Hypolipidemic activity of Moringa oleifera Lam., Moringaceae, on high fat diet induced hyperlipidemia in albino rats / Atividade hipolipidemica de Moringa oleifera Lam., Moringaceae, na hiperlipidemia induzida por dieta rica em gordura em ratos albinos

The leaves of Moringa oleifera Lam., Moringaceae, are used by the Indians in their herbal medicine as a hypolipidemic agent in obese patients. Albino Wistar rats were fed with methanolic extract of M. oleifera (150, 300 and 600 mg/kg, p.o.) and simvastatin (4 mg/kg, p.o.) along with hyperlipidemic diet for 30 days. Moringa oleifera and simvastatin were found to lower the serum cholesterol, triacylglyceride, VLDL, LDL, and atherogenic index, but were found to increase the HDL as compared to the corresponding high fed cholesterol diet group (control). The Moringa oleifera methanolic extract was also investigated for its mechanism of action by estimating HMG CO-A reductase activity. Moringa oleifera was found to increase the excretion of fecal cholesterol. Thus, the study demonstrates that M. oleifera possesses a hypolipidemic effect.

As folhas de Moringa oleifera Lam., Moringaceae, são usados na medicina natural da Índia como um agente hipolipemiante em pacientes obesos. Ratos albinos Wistar foram alimentados com extrato metanólico de M. oleifera (150, 300 e 600 mg/kg, p.o.) e sinvastatina (4 mg/kg, p.o.), juntamente com dieta hiperlipídica por 30 dias. Moringa oleifera e sinvastatina reduziram o colesterol, triacilglicerídeoss, VLDL, LDL e índice aterogênico, mas não aumentaram o HDL em comparação com o grupo controle, com dieta rica em colesterol. O mecanismo de ação do extrato metanólico de Moringa oleifera foi também investigado estimando atividade de HMG CO-A redutase. Moringa oleifera aumentou a excreção fecal de colesterol. Assim, o estudo demonstra que a M. oleifera parece ter efeito hipolipemiante.