Antidiabetic, antihyperlipidemic and antioxidant properties of ethanol extract of Grewia asiatica Linn. bark in alloxan-induced diabetic rats.

BACKGROUND: Inspite of introduction of oral hypoglycemic agents, diabetes and its related complications remains to be a major clinical problem. The aim of this study was to investigate the antidiabetic, antihyperlipidemic and antioxidant activities of Grewia asiatica (Linn) stem bark in alloxan induced diabetic rats. METHODS: Diabetes was induced by a single dose of intraperitoneal injection of alloxan (110 mg/kg) in Norwegian Long Evans rats. Ethanol extract of barks from Grewia asiatica (GAE 200 and 400 mg/kg) and metformin (150 mg/kg) were orally administered once daily for 15 days. Blood glucose levels and body weights of rats were measured on 0, 5, 10 and 15 days of oral treatment. At the end of the experiment the rats were sacrificed and blood sample were collected for the measurement of total cholesterol (TC), triglycerides (TG), very low density lipoproteins (VLDL), low density lipoproteins (LDL), high density lipoproteins (HDL), SGOT and CK-MB. Analysis of liver glycogen content and histopathlogy of pancreas were carried out. In vitro DPPH free radical scavenging activity, total phenolic and total flavonoid content of GAE were also determined. RESULTS: After 15 days of oral administration of GAE at doses of 200 and 400 mg/kg increased survival rate and showed a significant attenuation in blood glucose and lipid profile in diabetic rats. Oral ingestion of GAE significantly reduced the SGOT and CK-MB levels and restored liver glycogen content when compared to diabetic control. The effects of GAE on SGOT, CK-MB and liver glycogen content were dose-dependent. The diabetic rats treated with GAE showed significant improvement in normal cellular population size of islets. Phytochemical screening of GAE revealed the presence of flavonoid, steroid, tannin and phenolic compounds. Total phenolic content was 44.65 ± 3.17 mg of gallic acid equivalent per gm of GAE extract and the total flavonoid content was 39.11 ± 4.65 mg of quercetin equivalent per gm of GAE extract. In DPPH scavenging assay, IC50 values of GAE and ascorbic acid were found 76.45 and 12.50 µg/ml, respectively. CONCLUSION: We demonstrated that ethanol extract of barks from G. asiatica possess glucose, lipid lowering efficacy, restored liver glycogen and protects pancreas from oxidative damage in alloxan-induced diabetic rats. Thus, the results of the present study provide a scientific rationale for the use of G. asiatica in the management of diabetes and its related complications.

Antidiabetic and antioxidant activities of ethanolic extract of Semecarpus anacardium (Linn.) bark.

BACKGROUND: Diabetes mellitus is a global health problem and constantly increasing day by day. The number of diabetic people in world is expected to rise to 366 million in 2030. The available drugs for diabetes, insulin or oral hypoglycemic agents have one or more side effects and search for new antidiabetic drugs with minimal or no side effects from medicinal plants is a challenging for us. The present study was undertaken to investigate the antidiabetic and antioxidant activity of Semecarpus anacardium (Linn.) (abbreviated as SF). METHODS: The antidiabetic activity was determined by using alloxan-induced diabetic rats. After 15 days of treatment, serum biochemical parameters such as TC, TG, LDL, HDL, SGOT and SGPT were estimated. The survival rate, body weight, organ weight, liver glycogen and blood parameters (RBC and Hb) were also measured. The antioxidant activity was measured by DPPH free radical scavenging assay. Phytochemical screening, total phenolic and total flavonoid content were determined by using standard methods. RESULTS: The results showed that the survival rate was 100% in rats of Group SA 400. The effect of extract on blood glucose level in Groups SA 100, SA 200 and SA 400 were dose-dependent throughout the treatment period. No significant changes in organ weight to body weight ratio were observed, liver weights significantly improved in Groups SA 200 and SA 400. The bark extract exhibited significant (p < 0.05) anti-diabetic activity with lowering TC, TG, LDL level dose-dependently and protected liver which may be partially explained by attenuation of SGOT and SGPT levels and increases liver glycogen. The percentage of Hb and RBC counts were negatively correlated with the doses of extracts. In DPPH scavenging assay, IC50 values of SA extract and ascorbic acid were found 72.24 µg/ml and 17.81 µg/ml, respectively. Phytochemical screening showed the presence of steroids, triterpenoids, flavonoids, glycosides, saponins, and tannins that were contribute to biological activity. CONCLUSIONS: These results indicated that stem barks of S. anacardium possess strong anti-diabetic and antioxidant potentials and support traditional medicinal use for the treatment of diabetes mellitus and good source for natural antioxidants.

NMR analyses on the interactions of the yeast Tim50 C-terminal region with the presequence and Tim50 core domain.

The mitochondrial targeting signal in the presequence of mitochondrial precursor proteins is recognized by Tom20 and subsequently by Tim50 in mitochondria. Yeast Tim50 contains two presequence binding sites in the conserved core domain and in the fungi-specific C-terminal presequence binding domain (PBD). We report the NMR analyses on interactions of a shorter variant of PBD (sPBD), a shorter variant of PBD, with presequences. The presequence is recognized by sPBD in a similar manner to Tom20. sPBD can also bind to the core domain of Tim50 through the presequence binding region, which could promote transfer of the presequence from sPBD to the core domain in Tim50.

Antidiabetic and hypolipidemic effects of different fractions of Coccinia cordifolia L. on normal and streptozotocin-induced diabetic rats.

The present study was carried out to observe the antidiabetic and hypolipidemic effects of petroleum-ether, ethyl acetate and chloroform fractions isolated from ethanolic extract of the leaves of Coccinia cordifolia Linn. (150 mg/kg body weight) on normal and streptozotocin (STZ)-induced diabetic rats for one day experiment. Single doses (150 mg/kg, i.p.) of C. cordifolia extracts were given to normal and diabetic rats. The fasting blood glucose (FBG), serum triglyceride (TG) and serum total cholesterol (TC) levels were investigated in normal and STZ-diabetic rats on 0, 1, 2, 3, 6, 10, 16, and 24th hours. In normoglycemic rats the pet-ether and ethyl acetate fractions of C. cordifolia reduced blood glucose level significantly (39.66% and 40.68% at 16th and 24th hour respectively). In the STZ-diabetic rats pet-ether and ethyl acetate fractions also reduced blood glucose level significantly (50.39% and 50% at 10th and 24th hour respectively). Ethyl acetate fraction is most effective which reduced total cholesterol level by 31.04% and 36.69% in normal and STZ-diabetic rats respectively. Ethyl acetate fraction reduced triglyceride level by 43.82% and 42.01% in normal and STZ-diabetic rats respectively. Our results indicate that pet-ether and ethyl acetate fractions of C. cordifolia have potentiality against diabetes.

Oral glucose tolerance test (OGTT) in normal control and glucose induced hyperglycemic rats with Coccinia cordifolia l. and Catharanthus roseus L.

The aim of this study is to investigate the hypoglycemic effects of petroleum ether, chloroform and ethyl acetate fractions isolated from ethanolic extracts of Coccinia cordifolia and Catharanthus roseus on normal control and orally glucose-induced hyperglycemic rats. Single doses (150 mg/kg) of different fractions of C. cordifolia and C. roseus extracts were intraperitonelly administered. The serum blood glucose level was obtained by pricking the tail vein using glucometer at time 0, 30, 60, 90, 150 and 270 minutes. In the orally glucose induced hyperglycemic rats, chloroform-coccinia (CHCl3-CC) fraction showed maximum reduction of blood glucose level by 21.94% on 60 minute of the experiment. On the other hand maximum reduction (p<0.05) of 17.92% was observed for petroleum ether-catharanthus (PET-CR) on 30 minute of the experiment. Metformin HCl was used as standard drug. Our results indicate that the CHCl3-CC fraction is relatively more potent than other fractions of C. cordifolia. Similarly the PET-CR is found to be better than other fractions of catharanthus. Phytochemical screening test results showed that chloroform fraction of C. cordifolia contain saponins and flavonoids compounds, which are known to be hypoglycemic. On the other hand petroleum ether fraction of C. roseus contains tannins, flavonoids and alkaloid compounds produced varying degree of blood sugar reduction. On the pharmacological point of view C. cordifolia and C. roseus appears to be a valuable plant, which can be useful, at least as an adjunct, in the therapy of diabetes.

Effect of starch 1500 as a binder and disintegrant in lamivudine tablets prepared by high shear wet granulation.

High shear wet granulation is a preferred manufacturing method of tablets. It allowed for rapid production of compressible granulations. The resultant granulation characteristics depend on a combination of formulation properties and processing parameters. Fully pregelatinized starches are currently being used as binders in wet granulated formulations. But due to the gelatinization, much of the disintegration properties are lost. Partially pregelatinized starches (starch 1,500) have a mixture of properties of both native and fully gelatinized starches; made them useful as both a binder and a disintegrant in wet granulated formulations. Starch 1,500 performed as an excellent binder producing a granulation that was compressible and produced lamivudine tablets of improved hardness and friability compared with those prepared with povidone. The formulation of lamivudine tablets with starch 1,500 exceeded the disintegration and dissolution performance of the povidone formulation that utilized a super disintegrant. High shear wet granulation is also well suited for the use of partially pregelatinized starches.

Simultaneous high-performance liquid chromatographic determination of atenolol and amlodipine in pharmaceutical-dosage form.

A simple, rapid and precise method is developed for the quantitative simultaneous determination of atenolol and amlodipine in a combined pharmaceutical-dosage form. The method is based on High Performance Liquid Chromatography (HPLC) on a reversed-phase column, shim-pack CLC, ODS (C18), 4.6 mmx25 cm & 0.5 mm, using a mobile phase of ammonium acetate buffer (the pH was adjusted to 4.5+/-0.05 with glacial acetic acid), acetonitrile and methanol (35::30:35 v/v). The buffer used in the mobile phase contains ammonium acetate in double-distilled water. The chromatographic conditions are- flow rate of 1.5 ml/min, column temperature at 40 degrees C and detector wavelength of 237 nm. Both the drugs were well resolved on the stationary phase and the retention times were around 1.5 minute for atenolol and 3.4 minute for amlodipine. The method was validated and shown to be linear for atenolol and amlodipine. The correlation coefficients for atenolol and amlodipine are 0.999963 and 0.999979, respectively. The relative standard deviations for six replicate measurements in two sets of each drug in the tablets is always less than 2% and mean % error of active recovery not more than +/-1.5%. The method was validated for precision and accuracy. The proposed method was successfully applied to the pharmaceutical dosage forms containing the above-mentioned drug combination without any interference by the excipients.