Inhibitory Potential of Six Brown Algae from the Persian Gulf on α-Glucosidase and In Vivo Antidiabetic Effect of Sirophysalis Trinodis.

Background: Brown algae have gained worldwide attention due to their significant biological activities, such as antidiabetic properties. In the present study, the antidiabetic properties of six brown algae from the Persian Gulf were investigated. Methods: An experimental study was conducted from 2017 to 2019 to examine the inhibitory effects of six brown algae against the α-glucosidase activity. Methanol (MeOH) and 80% MeOH extracts of Colpomenia sinuosa, Sargassum acinaciforme, Iyengaria stellata, Sirophysalis trinodis, and two accessions of Polycladia myrica were analyzed. The effect of 80% MeOH extracts of Sirophysalis trinodis on blood glucose levels in streptozotocin-induced diabetic rats was evaluated. Chemical constituents of brown algae were analyzed using thin-layer chromatography and liquid chromatography-mass spectrometry techniques. Data were analyzed using SPSS software, and P<0.05 was considered statistically significant. Results: The 80% MeOH extracts of Iyengaria stellata (IC50=0.33±0.15 µg/mL) and Colpomenia sinuosa (IC50=3.50±0.75 µg/mL) as well as the MeOH extracts of Colpomenia sinuosa (IC50=3.31±0.44 µg/mL) exhibited stronger inhibitory effect on α-glucosidase than the acarbose (IC50=160.15±27.52 µg/mL, P<0.001). The 80% MeOH extracts of Sirophysalis trinodis reduced postprandial blood glucose levels in diabetic rats compared to the control group (P=0.037). Fucoxanthin was characterized as the major antidiabetic agent in most of the algal extracts. Conclusion: Sirophysalis trinodis is recommended as a novel source for isolation and identification of potential antidiabetic compounds due to its high in vivo and in vitro antidiabetic effects.

Quantitative 3D OPT and LSFM datasets of pancreata from mice with streptozotocin-induced diabetes.

Mouse models for streptozotocin (STZ) induced diabetes probably represent the most widely used systems for preclinical diabetes research, owing to the compound's toxic effect on pancreatic ß-cells. However, a comprehensive view of pancreatic ß-cell mass distribution subject to STZ administration is lacking. Previous assessments have largely relied on the extrapolation of stereological sections, which provide limited 3D-spatial and quantitative information. This data descriptor presents multiple ex vivo tomographic optical image datasets of the full ß-cell mass distribution in mice subject to single high and multiple low doses of STZ administration, and in glycaemia recovered mice. The data further include information about structural features, such as individual islet ß-cell volumes, spatial coordinates, and shape as well as signal intensities for both insulin and GLUT2. Together, they provide the most comprehensive anatomical record of the effects of STZ administration on the islet of Langerhans in mice. As such, this data descriptor may serve as reference material to facilitate the planning, use and (re)interpretation of this widely used disease model.

Ameliorating activity of polyphenolic-rich extracts of Basella rubra L. leaves on pancreatic ß-cell dysfunction in streptozotocin-induced diabetic rats.

OBJECTIVES: To assess the ameliorative activity of polyphenolic-rich extracts of Basella rubra leaves on ß-cell dysfunction in type-II diabetes (T2DM). METHODS: Total phenolic and flavonoid contents; α-amylase and α-glucosidase inhibitory actions and qualitative analysis of the bioactive compounds of the polyphenolic-rich extract of B. rubra leaves were investigated using gas chromatography-mass spectroscopy (GC-MS). Diabetes mellitus (DM) was induced by single intraperitoneal injection of streptozotocin (60 mg/kg body weight) and the rats were orally given bound phenolic (BPE) and free phenolic extracts (FPE) of B. rubra (B.R) leaves at 200 and 400 mg/kg b.w once daily for 14 days. Biochemical analyses were executed for evaluation of serum insulin, serum lipid profile concentrations, liver enzymes activities. RESULTS: The extracts demonstrated antioxidant potentials and enzymes inhibitory activities in dose dependent manner; and several bioactive compounds as revealed by GC-MS. BPE and FPE considerably (p<0.05) reduced hyperglycemia, improved serum insulin levels, ameliorated the concentration of serum lipid profiles and improved liver antioxidant activities. Additionally, BPE and FPE expressively decreased alanine aminotransferases (ALT), aspartate aminotransferases (AST), gamma-glutamyl transferase (GGT) activities along with levels of bilirubin and urea when compare to diabetic control rats. CONCLUSIONS: Data acquired exhibited the ability of BPE and FPE to improve pancreatic beta-cell in streptozotocin-induced rats.

Levan from Bacillus subtilis Natto: its effects in normal and in streptozotocin-diabetic rats

Levan is an exopolysaccharide of fructose primarily linked by ƒÀ-(2¨6) glycosidic bonds with some ƒÀ-(2¨1) branched chains. Due to its chemical properties, levan has possible applications in both the food and pharmaceutical industries. Bacillus subtilis is a promising industrial levan producer, as it ferments sucrose and has a high levan-formation capacity. A new strain of B. subtilis was recently isolated from Japanese food natto, and it has produced levan in large quantities. For future pharmaceutical applications, this study aimed to investigate the effects of levan produced by B. subtilis Natto, mainly as potential hypoglycemic agent, (previously optimized with a molecular weight equal to 72.37 and 4,146 kDa) in Wistar male rats with diabetes induced by streptozotocin and non-diabetic rats and to monitor their plasma cholesterol and triacylglycerol levels. After 15 days of experimentation, the animals were sacrificed, and their blood samples were analyzed. The results, compared using analysis of variance, demonstrated that for this type of levan, a hypoglycemic effect was not observed, as there was no improvement of diabetes symptoms during the experiment. However, levan did not affect any studied parameters in normal rats, indicating that the exopolysaccharide can be used for other purposes.

Anomer-equilibrated streptozotocin solution for the induction of experimental diabetes in mice (Mus musculus).

Streptozotocin is widely used to induce diabetes in laboratory animals through multiple low-dose or single high-dose intraperitoneal injections. HPLC analysis has shown that the composition of the solution may change considerably during the first 2 h after dissolution due to equilibration of the 2 anomers (alpha and beta) of streptozotocin. Because of the drug's alleged instability in solution, the typical recommendation is to administer streptozotocin within 10 min after dissolution. We compared the induction of diabetes in NOD/SCID mice by injection of a single high dose of freshly made or anomer-equilibrated streptozotocin solution. Solutions were prepared from dry compound containing 85% of the alpha anomer, which is the more toxic of the 2. Body weight and nonfasting blood glucose levels were measured weekly for 8 wk. Both solutions induced long-term hyperglycemia, but blood glucose levels and mortality were higher and damage to pancreatic islands more pronounced in the mice receiving freshly prepared solution. A small proportion of mice did not respond in both treatment groups. If stored at 4 degrees C in the dark, the anomer-equilibrated solution retains its biologic activity for at least 40 d; under those conditions the streptozotocin content decreases by 0.1% daily, as determined by HPLC. Anomer-equilibrated streptozotocin solution has several practical advantages, and we recommend its use as standard for the induction of experimental diabetes because this practice may improve reproducibility and comparison of results between different laboratories.

Functional and histochemical analysis on pancreatic islets of APA hamsters with SZ-induced hyperglycemia and hyperlipidemia.

To clarify how Syrian hamsters of the APA strain (APA hamsters) keep a diabetic condition for a long period, the functional and histochemical changes in the pancreatic islets of diabetic APA hamsters were examined. By glucose tolerance test, no glucose-induced insulin secretion was seen in the diabetic APA hamsters. By immunohistochemistry, it was revealed that at 24 hr after SZ-injection, the number of islets had decreased and that remnant islets had become markedly smaller. The islets had hardly any insulin-immunoreactive cells and consisted of cells stained by anti-glucagon and somatostatin antibodies. One, three and six months after SZ-injection, a small number of cells with vacuolative changes, which were positive for PAS staining, were observed in most islets and the vacuolated cells were stained mainly by anti-insulin antibody. In addition, a number of PCNA-positive cells were observed, especially in the periphery of the vacuolated cells, while TUNEL-positive cells were not detected. This data suggests that beta-cells proliferating as a result of the replication of the resident beta-cells in islets had fallen into degeneration and necrosis by a stress, such as the glycogen deposition in hyperglycemia and hyperlipidemia. Consequently, secretion of insulin was maintained at low levels, which allowed the hamsters to live without insulin therapy in the diabetic condition for over 6 months.

Análise histomorfométrica da reparaçäo de alvéolos infectados após extraçäo dental em ratos diabéticos controlados e näo controlados / Histomorphometric analusis of infected denta socket repair after tooth extraction in controlled and uncontrolled diabetics rats

O processo de reparo em alvéolos dentais infectados de ratos (Rattus novegicus, albinus, Wistar) diabéticos controlado e näo controlado foi avaliado qualitativa e quantitativamente. Para isso foram utilizados 60 animais. O Grupo I (Controle) foi submetido à inoculaçäo de soluçäo tampäo, os Grupos II e III (Diabéticos) receberam estreptozotocina (45mg/Kg), dissolvida em tampäo citrato 0,01M, sendo administradas 3 unidades/dia de insulina apenas no Grupo III (Diabético controlado). Após a verificaçäo do estado glicêmico dos animais, todos os incisivos superiores direitos foram extraídos e induziu-se a alveolite com soluçäo salina pré-reduzida e epinefrina. Os animais foram sacrificados no 3§, 7§, 14§ e 28§ dias pós-operatórios. Suas maxilas foram separadas, fixadas em formalina, descalcificadas em EDTA e incluídas em parafina. Os cortes com 6µm de espessura foram corados com Hematoxilina e eosina (H.E.) e Tricrômio de Masson. Após a análise qualitativa e quantitativa ao microscópio óptico e histometria óssea com o Software Imagelab, os resultados foram submetidos ao teste de Kruskal-Wallis. Concluiu-se que: qualitativamente o reparo alveolar do grupo diabético näo controlado foi mais retardado em relaçäo ao controle e ao diabético controlado nas últimas fases da reparaçäo sem apresentar diferenças estatisticamente significantes

High-pressure liquid chromatographic separation and determination of anomeric forms of streptozocin in a powder formulation.

A high-pressure liquid chromatographic assay for streptozocin in a sterile powder formulation (1.0 g/vial) is described. The method effectively separates the alpha- and beta-anomeric forms of streptozocin. Quantitative results are presented for the drug based on the use of an internal standard and peak height measurements.