Effect of Marantodes pumilum Blume (Kuntze) var.alata on β-cell function and insulin signaling in ovariectomised diabetic rats

BACKGROUND

Oestrogen deficiency leads to metabolic disturbances such as insulin resistance and impairment of adipose tissue or lipid metabolism. Marantodes pumilum (Blume) Kuntze (Primulaceae) is believed to have phytoestrogenic properties and is claimed to have beneficial effects in the treatment of diabetes mellitus (DM), but the mechanism behind its phytoestrogenic effects on estrogen-deficient diabetic condition have not been fully examined.

PURPOSE

The present study investigated the effects of oral treatment with M. pumilum var. alata (MPA) extracts on the estrogen receptor, metabolic characteristics and insulin signaling pathway in pancreas and liver of ovariectomised nicotidamide streptozotocin-induced diabetes in female rats.

MATERIALS AND METHODS

Ovariectomised diabetic (OVXS) Sprague-Dawley rats were orally administered with either aqueous leaf extract and ethanol (50%) stem-root extract of MPA (50 or 100 mg/kg) respectively for 28 days. Metabolic parameters were evaluated by measuring fasting blood glucose, serum insulin, oral glucose and insulin tolerance test. Distribution and expression level of insulin, oxidative stress and inflammatory marker in the pancreatic islets and liver were evaluated by immunohistochemistry and western blot, respectively.

RESULTS

Oral treatment with aqueous leaf and ethanol (50%) stem-root extracts of MPA (100 mg/kg) significantly reversed the elevated fasting blood glucose, impaired glucose and insulin tolerance. The protein expression of insulin, glucose transporter (GLUT-2 and GLUT-4) increased in the pancreatic islets and liver. Furthermore, marked improvement in the tissue morphology following treatment with MPA was observed. Similarly, the western blots analysis denotes improved insulin signaling in the liver and decreased reactive oxygen species producing enzymes, inflammatory and pro-apoptotic molecules with MPA treatment.

CONCLUSIONS

Taken together, this work demonstrate that 100 mg/kg of aqueous leaf extract and ethanol (50%) stem-root extract of MPA improves β-cell function and insulin signaling in postmenopausal diabetes through attenuation of oxidative stress and partially mediated by oestrogen receptor stimulation.

The development of an inhibitive determination method for zinc using a serine protease

A new inhibitive heavy metals determination method using trypsin has been developed. The enzyme was assayed using the casein-Coomassie-dye-binding method. In the absence of inhibitors, casein was hydrolysed to completion and the Coomassie-dye was unable to stain the protein and the solution became brown. In the presence of metals, the hydrolysis of casein was inhibited and the solution remained blue. The bioassay was able to detect zinc and mercury with IC50 (concentration causing 50% inhibition) values of 5.78 and 16.38 mg l(-1) respectively. The limits of detection (LOD), for zinc and mercury were 0.06 mg l(-1) (0.05-0.07, 95% confidence interval) and 1.06 mg l(-1) (1.017-1.102, 95% confidence interval), respectively. The limits of quantitation (LOQ) for zinc and mercury were 0.61 mg l(-1) (0.51-0.74 at a 95% confidence interval) and 1.35 mg l(-1) (1.29-1.40 at a 95% confidence interval), respectively. The IC50 value for zinc was much higher than the IC50 values for papain and Rainbow trout, but was within the range of Daphnia magna and Microtox. The IC50 value for zinc was only lower than those for immobilized urease. Other toxic heavy metals, such as lead, silver arsenic, copper and cadmium, did not inhibit the enzyme at 20 mg l(-1). Using this assay we managed to detect elevated zinc concentrations in several environmental samples. Pesticides, such as carbaryl, flucythrinate, metolachlor glyphosate, diuron, diazinon, endosulfan sulphate, atrazine, coumaphos, imidacloprid, dicamba and paraquat, showed no effect on the activity of trypsin relative to control (One-way ANOVA, F(12,26)= 0.3527, p> 0.05). Of the 17 xenobiotics tested, only (sodium dodecyl sulphate) SDS gave positive interference with 150% activity higher than that of the control at 0.25% (v/v).

Inhibitory effect of compounds from Zingiberaceae species on human platelet aggregation

Twelve compounds isolated from Alpinia mutica Roxb., Kaempferia rotunda Linn., Curcuma xanthorhiza Roxb., Curcuma aromatica Valeton and Zingiber zerumbet Smith (Family: Zingiberaceae) and three synthesized derivatives of xanthorrhizol were evaluated for their ability to inhibit arachidonic acid- (AA), collagen- and ADP-induced platelet aggregation in human whole blood. Antiplatelet activity of the compounds was measured in vitro by the Chrono Log whole blood aggregometer using an electrical impedance method. Among the compounds tested, curcumin from C. aromatica, cardamonin, pinocembrine and 5,6-dehydrokawain from A. mutica and 3-deacetylcrotepoxide from K. rotunda showed strong inhibition on platelet aggregation induced by AA with IC(50) values of less than 84 microM. Curcumin was the most effective antiplatelet compound as it inhibited AA-, collagen- and ADP-induced platelet aggregation with IC(50) values of 37.5, 60.9 and 45.7 microM, respectively.

Removal of acyclovir during continuous veno-venous hemodialysis and hemodiafiltration with high-efficiency membranes

We present a critically ill patient with severe renal failure and anuria who underwent hemodialysis (HD), continuous veno-venous hemodialysis (CVVHD) and continuous veno-venous hemodiafiltration (CVVHDF) at different occasions, with 2 commonly used high-efficiency dialyzers (F-8 and CA-210), while receiving i.v. acyclovir. We estimate that during 24 hours of CVVHD with F-8 dialyzer approximately 18% and during 24 hours of CVVHDF with CA-210 dialyzer approximately 65% of the daily administered acyclovir is removed. This is comparable to the amount removed during 4 6 hours of HD, as reported previously. The percentage acyclovir extraction was 84% and 60% during CVVHD and CVVHDF with F-8 and CA-210 dialyzers, respectively. Acyclovir clearance during CVVHD was 14 ml/min and during CVVHDF was 17 ml/min, with F-8 and CA-210 dialyzers, respectively. Acyclovir half-life was 22.5 and 25.5 hours in 2 occasions off any type of renal replacement therapy, and it was 19.5 hours during CVVHDF with CA-210 dialyzer.

Removal of morphine with the new high-efficiency and high-flux membranes during haemofiltration and haemodialfiltration

We present three critically ill patients with severe renal failure who required haemofiltration or haemodiafiltration, with high-efficiency or high-flux membranes, while receiving an intravenous infusion of morphine. We show that despite the very high ultrafiltrability/diffusability of free morphine, only 1-3% of the total amount of infused morphine is removed in 24 h. This is in marked contrast to haemodialysis where, owing to much higher dialysate flow rate, a significant quantity of free morphine is removed.