Lichen Parmelia sulcata mediated synthesis of gold nanoparticles: an eco-friendly tool against Anopheles stephensi and Aedes aegypti.

The gold nanoparticles (AuNPs) were synthesized using the lichen Parmelia sulcata extract (PSE) and characterized. The peaks of ultraviolet spectrophotometer and Fourier transmission infrared confirmed the formation of nanoparticles and the bioactive compounds of the lichen being responsible for reducing and capping of the particles. The face-centered cubic particles were determined by XRD peaks at 111, 200, 220, and 311. The elemental composition and spherical shape of AuNPs were confirmed by energy-dispersive spectroscopy and transmission electron microscopy. The average particle size is 54 nm, and the zeta potential - 18 was ascertained by dynamic light scattering. The potential effect of synthesized nanoparticles and lichen extracts was evaluated for antioxidant bioassays like DPPH and H2O2 and tested for mosquitocidal activity against Anopheles stephensi. Results showed that the lichen extract and AuNPs have the capability to scavenge the free radicals with the IC50 values of DPPH being 1020 and 815 µg/ml and the IC50 values of H2O2 being 694 and 510 µg/ml, respectively. The mosquitocidal experimental results in this study showed the inhibition of A. stephensi and A. aegypti against the larvae (I-IV instar), pupae, adult, and egg hatching. On comparison, A. stephensi showed effective inhibition than A. aegypti even at low concentration. Based on the obtained results, gold nanoparticles synthesized using PSE showed an excellent mosquitocidal effect against Anopheles stephensi.

Quercitrin a bioflavonoid improves the antioxidant status in streptozotocin: induced diabetic rat tissues.

Quercitrin, a bio flavonoid, was investigated for its antioxidant potential in streptozotocin (STZ)-induced diabetic rats. Rats were induced diabetic by a single intraperitoneal injection of streptozotocin (50 mg/kg). The levels of fasting plasma glucose and insulin were estimated. Lipid peroxidative products and antioxidants were estimated in pancreas, liver, and kidney. Histopathological studies were carried out in these tissues. A significant (P < 0.05) increase in the levels of fasting plasma glucose and lipid peroxidative products (thiobarbituric acid reactive substances and lipid hydroperoxides) and a significant (P < 0.05) decrease in plasma insulin, enzymic antioxidants (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase), and nonenzymic antioxidants (reduced glutathione, vitamin C, and E) in diabetic pancreas, liver, and kidney were observed. Oral administration of quercitrin (30 mg/kg) for a period of 30 days significantly (P < 0.05) decreased fasting plasma glucose, increased insulin levels, and improved the antioxidant status of diabetic rats by decreasing lipid peroxidative products and increasing enzymic and nonenzymic antioxidants. Normal rats treated with quercitrin (30 mg/kg) showed no significant (P < 0.05) effect on any of the parameters studied. Histopathological studies of the pancreas, liver, and kidney showed the protective role of quercitrin. Thus, our study clearly shows that quercitrin has antioxidant effect in STZ-induced experimental diabetes.

Quercitrin, a bioflavonoid improves glucose homeostasis in streptozotocin-induced diabetic tissues by altering glycolytic and gluconeogenic enzymes.

The present study is an investigation into the role of quercitrin on carbohydrate metabolism in normal and streptozotocin (STZ)-induced diabetic rats. Administration of STZ leads to a significant increase (P < 0.05) in fasting plasma glucose and a decrease in insulin levels. The content of glycogen is significantly decreased (P < 0.05) in liver and muscle, but increased in the kidney. The activity of hexokinase decreased whereas the activities of glucose 6-phosphatase and fructose 1,6-bisphosphatase significantly increased (P < 0.05) in the tissues. Oral administration of quercitrin (30 mg/kg) to diabetic rats for a period of 30 days resulted in significant (P < 0.05) alterations in the parameters studied but not in normal rats. A decrease of plasma glucose and increase in insulin levels were observed along with the restoration of glycogen content and the activities of carbohydrate metabolic enzymes in quercitrin-treated diabetic rats. The histopathological study of the pancreas revealed the protective role of quercitrin. There was an expansion of the islets and decreased fatty infiltrate of the islets in quercitrin treated diabetic rats. In normal rats treated with quercitrin, we could not observe any significant change in all the parameters studied. Combined, these results show that quercitrin plays a positive role in carbohydrate metabolism and antioxidant status in diabetic rats.