Effect of long-term treatment with a purified micronized flavonoid fraction on pancreatic mononuclear cell infiltration in diabetic BB rats

Diosmin exerts hepatoprotective and antihyperglycemic effects against sodium arsenite-induced toxicity through the modulation of oxidative stress and inflammation in mice

BACKGROUND

Chronic exposure to high concentrations of inorganic arsenic (NaAsO₂) in drinking water is related to an increase in the risk of liver toxicity and diabetes. Diosmin has various pharmacological properties, including antioxidant and anti-inflammatory properties. This study was designed to investigate the protective effects of diosmin on diabetes and hepatotoxicity caused by NaAsO₂.

METHODS

Sixty male 8-week-old NMRI mice, weighing 25 ± 2 g, were randomly selected and put into six groups. The control (Group 1) was treated orally with distilled water, group 2 was treated with diosmin (100 mg/kg, p.o), group 3 received NaAsO₂ (10 mg/kg, p.o), and groups 4, 5, 6 received diosmin (25, 50, 100 mg/kg, p.o), respectively and NaAsO₂ (10 mg/kg, p.o). After 29 days, fasting blood sugar (FBS) measurement and glucose tolerance test were done. The mice were sacrificed on day 31, and blood and tissue (liver and pancreas) samples were taken. Then, serum and tissue samples were studied for biochemical and histological evaluations.

RESULTS

The results demonstrated that diosmin ameliorated glucose intolerance and decreased FBS compared to the NaAsO₂ group. Diosmin (50 and 100 mg/kg) improved the serum factors of liver function (alanine aminotransferase, aspartate transaminase, and alkaline phosphatase) in the groups receiving NaAsO₂. Moreover, increased levels of nitric oxide, tumor necrosis factor-alpha, and thiobarbituric acid reactive substances in liver tissue induced by NaAsO₂ were diminished by diosmin treatment. Administration of diosmin increased total thiol and enzymatic activities of catalase, superoxide dismutase, and glutathione peroxidase in liver tissue. Furthermore, treatment with diosmin reduced the increase in protein amount of Sirtuin 3 and nuclear factor kappa B in the groups receiving NaAsO₂. Also, the liver and pancreas histological lesions induced by NaAsO₂ were attenuated by diosmin treatment.

CONCLUSION

Diosmin has a preventive effect against hepatotoxicity and diabetes induced by NaAsO₂ in mice through its antioxidant and anti-inflammatory properties.

Protective effect of diosmin on LPS-induced apoptosis in PC12 cells and inhibition of TNF-α expression

Several studies have demonstrated a link between increased pro-inflammatory mediators and apoptosis in neurodegenerative diseases. It has been reported that lipopolysaccharide (LPS) induces apoptosis mostly through the production of TNF-α. In this study, we investigated the possible protective and anti-inflammatory mechanisms of diosmin, a natural flavone glycoside, on LPS-induced PC12 cells death through inhibition of TNF-α production. PC12 Cells were pretreated with diosmin for 2h prior to LPS treatment for 48 h to assess PC12 cells viability, TNF-α expression, and cell death mechanisms. Diosmin significantly increased cells survival and suppressed LPS-induced TNF-α in a concentration-dependent manner. Diosmin also significantly reduced the DNA fragmentation of LPS-induced cells, and its anti-apoptotic effect was confirmed by the decrease in the expression of pro-apoptotic protein Bad and the increase in the expression of anti-apoptotic protein Bcl-2 on Western blot analysis. Furthermore, diosmin inhibited LPS-induced caspase-3 activation further confirming its anti-apoptotic effects. This is the first study to report the anti-inflammatory and anti-apoptotic effects of diosmin via inhibition of TNF-α and a caspase-dependent pathway in neuronal PC12 cells. These results support the potential for diosmin to be investigated as a potential agent for the treatment of neurodegenerative diseases.