Zinc Supplementation Restores Altered Biochemical Parameters in Stomach Tissue of STZ Diabetic Rats.

The stomach is among the organs grossly affected organ by diabetic complications. The present study was aimed at investigating the protective role of zinc on stomach of streptozotocin (STZ)-induced diabetes mellitus. Female Swiss albino rats were divided in four experimental groups: Group I, control; group II, control + zinc sulfate; group III, STZ-induced diabetic animals; and group IV, STZ-diabetic + zinc sulfate. Diabetes was induced by intraperitoneal injection of STZ, at a dose of 65 mg/kg body weight. Zinc sulfate (100 mg/kg body weight) was given daily by gavage for 60 days to groups II and IV. At the end of the experiment, the rats were sacrificed, and the tissues were taken. In the diabetic group, hexose, hexosamine, fucose, and sialic acid levels, as well as tissue factor, adenosine deaminase, carbonic anhydrase, xanthine oxidase, lactate dehydrogenase, prolidase activities, advanced oxidized protein products, homocysteine, and TNF-α levels were increased in the stomach tissue homogenates. Whereas, catalase, superoxide dismutase, glutathione-S-transferase, glutathione peroxidase, glutathione reductase, paraoxonase, and aryl esterase activities were decreased in the diabetic group. The administration of zinc reversed all the deformities. These findings suggest that zinc has protective role in ameliorating several mechanisms of STZ-induced diabetic stomach injury.

Comparative Study on the Anticancer Drug Potential of a Lectin Purified from Aloe Vera and Aloe-Emodin.

BACKGROUND: The effect of Aloctin, a lectin purified from Aloe vera leaves, and aloe emodin an anthraquinone glycoside purified from the leaves of the same plant, on several cancer cell lines was investigated. METHODS: Aloctin was isolated from A. vera leaf skin by ammonium sulphate precipitation and CNBr-Sepharose 4B-ovalbumin affinity chromatography. Specific new ligands for Aloctin were detected as fetuin and avidin by hemagglutination inhibition tests. The cytotoxic effect of Aloctin and aloe emodin on various human cancer cell lines was tested using MTT assay. Imatinib was tested as standard positive control. The mechanism underlying was tested by the Annexin V-FITC/PI test, with flow cytometry. RESULTS: The most sensitive cells to Aloctin and aloe emodin treatment, were identified as AGS human gastric adenocarcinoma cells. The effect was concentration dependent. It was shown that this effect does not occur by apoptosis or necrosis. In Aloctin-imatinib combinations studies, Aloctin significantly increased the cytotoxic effect of imatinib in a dose-dependent manner. It is expected that the results of this study will reveal important findings for the future use of A. vera lectin as well as aloe emodin in cancer research and contribution to lectin biochemistry.
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Zinc supplementation ameliorates glycoprotein components and oxidative stress changes in the lung of streptozotocin diabetic rats.

Zinc (Zn) is a component of numerous enzymes that function in a wide range of biological process, including growth, development, immunity and intermediary metabolism. Zn may play a role in chronic states such as cardiovascular disease and diabetes mellitus. Zn acts as cofactor and for many enzymes and proteins and has antioxidant, antiinflammatory and antiapoptotic effects. Taking into consideration that lung is a possible target organ for diabetic complications, the aim of this study was to investigate the protective role of zinc on the glycoprotein content and antioxidant enzyme activities of streptozotocin (STZ) induced diabetic rat tissues. Female Swiss albino rats were divided into four groups. Group I, control; Group II, control + zinc sulfate; Group III, STZ-diabetic; Group IV, diabetic + zinc sulfate. Diabetes was induced by intraperitoneal injection of STZ (65 mg/kg body weight). Zinc sulfate was given daily by gavage at a dose of 100 mg/kg body weight every day for 60 days to groups II and IV. At the last day of the experiment, rats were sacrificed, lung tissues were taken. Also, glycoprotein components, tissue factor (TF) activity, protein carbonyl (PC), advanced oxidative protein products (AOPP), hydroxyproline, and enzyme activities in lung tissues were determined. Glycoprotein components, TF activity, lipid peroxidation, non enzymatic glycation, PC, AOPP, hydroxyl proline, lactate dehydrogenase, catalase, superoxide dismutase, myeloperoxidase, xanthine oxidase, adenosine deaminase and prolidase significantly increased in lung tissues of diabetic rats. Also, glutathione levels, paraoxonase, arylesterase, carbonic anhydrase, and Na(+)/K(+)- ATPase activities were decreased. Administration of zinc significantly reversed these effects. Thus, the study indicates that zinc possesses a significantly beneficial effect on the glycoprotein components and oxidant/antioxidant enzyme activities.

Effects of Aloe vera leaf gel extract on rat peritonitis model.

OBJECTIVES: The aim of this study was to investigate the antibacterial, anti-inflammatory, and antioxidant activities and probable toxic effects of Aloe vera (AV) in a rat peritonitis model. MATERIALS AND METHODS: RATS WERE DIVIDED INTO FIVE GROUPS: (1) Control group, (2) AV group, (3) peritonitis group (P), (4) peritonitis + AV group (P + AV), and (5) peritonitis + antibiotherapy group (P + Ab). Ultrafiltration (UF) rates were determined and colony and leukocyte counts were calculated in the dialysate. Glucose, blood urea nitrogen (BUN), creatinine levels, and alanine transaminase (ALT) activities were studied in blood. Glucose, interleukins (IL-1ß, IL-6), and prostaglandin E2 (PGE2) were studied in dialysate and peritoneal tissue for the assessment of the anti-inflammatory effect. Copper/zinc superoxide dismutase (Cu, Zn-SOD), malondialdehyde (MDA), and nitric oxide (NO) were also investigated in peritoneal tissue. RESULTS: Aloe vera increased the UF rate and lowered leukocyte numbers in the peritonitis group. There was no significant difference in blood and dialysate glucose, BUN, creatinine levels and ALT activity among control and AV groups. AV decreased IL-1ß, IL-6 and PGE2 in peritonitis, showing good anti-inflammatory effect. AV showed antioxidant effect on the chosen antioxidant parameters Cu, Zn-SOD, MDA, and NO. CONCLUSION: It was concluded that, AV might be used in peritonitis for its probable UF increasing, anti-inflammatory, and antioxidant effects.

Ameliorative effect of vanadium on oxidative stress in stomach tissue of diabetic rats.

Between their broad spectrum of action, vanadium compounds are shown to have insulin mimetic/enhancing effects. Increasing evidence in experimental and clinical studies suggests that oxidative stress plays a major role in the pathogenesis of diabetes and on the onset of diabetic complications. Thus, preventive therapy can alleviate the possible side effects of the disease. The aim of the present study was to investigate the effect of vanadyl sulfate supplementation on the antioxidant system in the stomach tissue of diabetic rats. Male Swiss albino rats were randomly divided into 4 groups: control; control+vanadyl sulfate; diabetic; diabetic+vanadyl sulfate. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ; 65 mg/kg body weight). Vanadyl sulfate (100 mg/kg body weight) was given daily by gavage for 60 days. At the last day of the experiment, stomach tissues were taken and homogenized to make a 10% (w/v) homogenate. Catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), myeloperoxidase (MPO), carbonic anhydrase (CA), glucose-6-phosphate dehydrogenase (G6PD) and lactate dehydrogenase (LDH) activities were determined in the stomach tissue. CAT, SOD, GR, GPx, GST, CA, G6PD and LDH activities were increased in diabetic rats when compared to normal rats. Vanadium treatment significantly reduced the elevated activities of GR, GPx, GST compared with the diabetic group whereas the decreases in CAT, SOD, CA, G6PD and LDH activities were insignificant. No significant change was seen for MPO activity between the groups. It was concluded that vanadium could be used for its ameliorative effect against oxidative stress in diabetes.

Influence of vanadium supplementation on oxidative stress factors in the muscle of STZ-diabetic rats.

In recent years, the role of free radical damage consequent to oxidative stress is widely discussed in diabetic complications. In this aspect, the protection of cell integrity by trace elements is a topic to be investigated. Vanadium is a trace element believed to be important for normal cell function and development. The aim of the present study was to investigate the effect of vanadyl sulfate supplementation on the antioxidant system in the muscle tissue of diabetic rats. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg body weight) to male Swiss albino rats. The rats were randomly divided into 4 groups: Group I, control; Group II, vanadyl sulfate control; Group III, STZ-diabetic untreated; Group IV, STZ-diabetic treated with vanadyl sulfate. Vanadyl sulfate (100 mg/kg) was given daily by gavage for 60 days. At the last day of the experiment, rats were killed, muscle tissues were taken, homogenized in cold saline to make a 10% (w/v) homogenate. Body weights and blood glucose levels were estimated at 0, 30 and 60th days. Antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), as well as carbonic anhydrase (CA), myeloperoxidase (MPO) activities and protein carbonyl content (PCC) were determined in muscle tissue. Vanadyl sulfate administration improved the loss in body weight due to STZ-induced diabetes and decreased the rise in blood glucose levels. It was shown that vanadium supplementation to diabetic rats significantly decrease serum antioxidant enzyme levels, which were significantly raised by diabetes in muscle tissue showing that this trace element could be used as preventive for diabetic complications.

Implications for degenerative disorders: antioxidative activity, total phenols, flavonoids, ascorbic acid, beta-carotene and beta-tocopherol in Aloe vera.

In order to demonstrate whether the known biological effects of Aloe vera (L.) Burm. fil. could correlate with the antioxidant activity of the plant, the antioxidant activity of the aqueous leaf extract was investigated. The present study demonstrated that the aqueous extract from A. vera leaves contained naturally occuring antioxidant components, including total phenols, flavonoids, ascorbic acid, beta-carotene and alpha-tocopherol. The extract exhibited inhibitory capacity against Fe(3+)/ascorbic acid induced phosphatidylcholine liposome oxidation, scavenged stable DPPH(*), ABTS(*+) and superoxide anion radicals, and acted as reductant. In contrast, the leaf inner gel did not show any antioxidant activity. It was concluded that the known beneficial effects of Aloe vera could be attributed to its antioxidant activity and could be related to the presence of phenolic compounds and antioxidant vitamins.

Tumour preventive effect of Aloe vera leaf pulp lectin (Aloctin I) on Ehrlich ascites tumours in mice.

In this study, the prophylactic effect of the main lectin present in Aloe vera leaf pulp extract (Aloctin I) was assayed against Ehrlich ascites tumours in mice. The lectin administered prophylactically before tumour implantation regressed tumour size, however, this activity was less potent than that of the A. vera leaf pulp extract previously shown in our laboratory. Accordingly, serum sialic acid and tumour necrosis factor alpha (TNFalpha) levels, chosen as tumour markers, were decreased significantly by the prophylactic administration of the lectin. The increase in spleen and thymus weights in the group given only Aloctin I, could be explained by the immunomodulatory and mitogenic effects of lectins. These findings, along with lymphoid hyperplasia observed in spleen and thymus, suggest that the tumour preventive effect of Aloctin I could be due to its immunomodulatory activity.

Effect of Aloe vera leaf pulp extract on Ehrlich ascites tumours in mice.

Among the various known therapeutic effects of Aloe vera (L.) Burm. fil., a few recent studies have shown that preparations of the plant leaves can prevent or regress the growth of certain tumours. In this study, undertaken with A. vera leaf pulp extract against Ehrlich ascites tumours in mice, the animals were separated into five groups: I - healthy control, II - tumour control, III - experiment 1 (extract given before tumour inoculation), IV - experiment 2 (extract given with tumour inoculation) and V - experiment 3 (extract given after tumour inoculation). Ehrlich ascites tumours (0.33 ml) were injected subcutaneously into groups II-V. Aloe extract was injected at 55 mg protein/kg, twice a week for 21 days. Tumour size, thymus and spleen weights were measured, as well as leucocyte count, tumour necrosis factor-alpha and sialic acid as tumour markers. The best inhibitory effect on tumour growth was obtained with the extract given prophylactically before tumour implantation (experiment 1), although Aloe extract also regressed tumour sizes when given simultaneously with (experiment 2), or therapeutically after (experiment 3), tumour implantation. Accordingly, serum sialic acid and tumour necrosis factor-alpha levels, chosen as tumour markers, which were raised in the tumour control group, were significantly decreased by the prophylactic administration of the extract. The increase in leucocyte count seen in experiment 1 and 2 groups, along with lymphoid hyperplasia observed in spleen and thymus necroscopy, lead us to think that the tumour preventive effect of Aloe could be due to its immunomodulatory activity. According to our results, A. vera could be proposed as a prophylactic for cancer prevention.

Effect of Aloe vera (L.) Burm. fil. leaf gel and pulp extracts on kidney in type-II diabetic rat models.

Significant degenerative changes were observed in the kidney tissue of untreated neonatal streptozotocin (n0STZ)-induced type-II diabetic rats. These degenerative changes were diminished in the kidney tissue of diabetic animals given glibenclamide and Aloe leaf gel and pulp extracts. Kidney lipid peroxidation levels were increased in diabetic rats compared to healthy rats; these levels were higher in rats treated with glibenclamide than in those which received Aloe extracts. Serum urea and creatinine levels were higher in diabetic rats in comparison to healthy rats. The administration of Aloe gel extract and glibenclamide decreased serum urea and creatinine levels in comparison to diabetic controls. Only A. vera leaf gel extract showed improvement both in histological and biochemical parameters suggesting a protective effect of A. vera on mild damage caused by type-II diabetes on kidney tissue.

Effect of Aloe vera leaf gel and pulp extracts on the liver in type-II diabetic rat models.

The aim of this work was to investigate the effects of Aloe vera leaf pulp and gel extracts on the liver tissue of neonatal streptozotocin (n0STZ)-induced type-II diabetic rats. The diabetic rats were separated into four groups and each group was given the following samples by gavage, daily for 15 d: phosphate buffered saline (PBS; diabetic control), Aloe leaf pulp extract, Aloe leaf gel extract, glibenclamide. Liver tissues were examined histologically. The markers of oxidative stress: glutathione (GSH), non-enzymatic glycosylation (NEG) and lipid peroxidation (LPO), were determined in liver tissue. Biochemical parameters for liver function: serum alkaline phosphatase (ALP), and alanine transaminase (ALP) activities, were evaluated. All parameters were also determined in healthy (non diabetic) rats for comparison. In the diabetic control group, the degenerative changes in liver tissue were remarkable, while in the diabetic groups given Aloe pulp and gel extracts and glibenclamide, the damage to the liver tissue was decreased. The increase of GSH and the decrease of NEG and LPO in liver tissues with the treatment of Aloe gel extract, is consistent with the beneficial effect of Aloe. Serum ALP and ALT activities were also decreased in the groups given Aloe gel extract. It was concluded that Aloe gel extract has a protective effect comparable to glibenclamide against hepatotoxicity produced by diabetes if used in the treatment of type-II diabetes.