Amelioration of Diabetes-Induced Diabetic Nephropathy by Aloe vera: Implication of Oxidative Stress and Hyperlipidemia.

This study investigated the effect of Aloe vera in diabetes-induced nephropathy in rats. As diabetes-associated hyperlipidemia and oxidative stress have been implicated in the pathogenesis of diabetic nephropathy, we evaluated the protective effect of whole leaf extract of Aloe vera on the basis of its hypolipidemic and antioxidative property. Aloe vera (300 mg/kg orally) has been noted to possess renoprotective effect in experimental diabetic nephropathy. However, its mechanism is not fully understood. Rats were administered streptozotocin (STZ) (55 mg/kg intraperitoneally once) to induce experimental diabetes mellitus. The development of diabetic nephropathy was assessed biochemically and histologically. In addition, the diabetes-induced lipid profile and renal oxidative stress were assessed. The single administration of STZ produced diabetes, which induced renal oxidative stress, altered the lipid profile, and subsequently produced nephropathy in eight weeks by increasing serum creatinine, blood urea nitrogen, proteinuria, and glomerular damage. Treatment with Aloe vera (300 mg/kg/day orally) was noted to be more effective against the diabetes-induced nephropathy and renal oxidative stress as compared to lisinopril (1 mg/kg/day orally), a reference agent. It may be concluded that diabetes-induced oxidative stress and lipid alterations may be accountable for the induction of nephropathy in diabetic rats. The treatment with Aloe vera (300 mg/kg/day orally) may have prevented the development of diabetes-induced nephropathy by reducing lipid alteration, decreasing renal oxidative stress, and providing direct renoprotective action.

Biochemical and spectroscopic characterization of a novel metalloprotease, cotinifolin from an antiviral plant shrub: Euphorbia cotinifolia.

A high molecular mass novel metalloprotease, cotinifolin is purified from the latex of Euphorbia cotinifolia by a combination of anion exchange and hydrophobic interaction chromatography. The nonglycosylated enzyme has a molecular mass of 79.76 kDa (ESI-MS) and the isoelectric point of the enzyme is pH 7.7. Cotinifolin hydrolyzes denatured natural substrates such as casein, azoalbumin, and hemoglobin with high specific activity. The K(m) value of the enzyme was found to be 20 µM with azocasein. The enzyme is not prone to autolysis even at very low concentrations. Polyclonal antibodies specific to enzyme was raised and immunodiffusion reveals that the enzyme has unique antigenic determinants. Maximum caseinolytic activity of cotinifolin is observed in the range of pH 7.0-8.0 and temperature of 50 °C. Using 0.2 mL of 1 mM solution of each metal ion, the purified protease was inhibited slightly by Ba²âº and Mn²âº, moderately by Mg²âº, Ca²âº and Cs²âº and significantly by Zn²âº, Cu²âº and Co²âº. On the other hand, substantial activation in caseinolytic activity was achieved by Ni²âº. The enzyme activity was also inhibited by EDTA and o-phenanthroline but not by any other protease inhibitors. Perturbation studies by temperature, pH, and chaotrophs of the enzyme also reveal its high stability as seen by CD, fluorescence and proteolytic activity. Spectroscopic studies reveal that cotinifolin has secondary structural features with α/ß type with approximately 9% of α-helicity. Easy availability and simple purification procedure makes the enzyme a good system for biophysical study, biotechnological and industrial applications.