Improvement of 2,2'-Azobis(2-Methylpropionamidine) Dihydrochloride-Induced Hepatic Redox Imbalance in Swiss Mice and HepG2 Cells by Rutin

Redox imbalance can lead to irreversible damages to biological functions. In this context, rutin stands out for its antioxidant potential. The objective of this study was to evaluate the acute and chronic effect of rutin on the hepatic redox imbalance. The study was performed according to three different protocols. First, healthy male Swiss mice were divided into two groups: control and rutin, the second of which received chronic oral supplementation of rutin (10 mg/kg). The second involved evaluation of the generation of reactive oxygen species (ROS) by HepG2 cells, incubated or not with rutin (20 and 40 μg/mL) for 3 h. The final protocol involved assessment of the acute effect of rutin (10 mg/kg) in mice with oxidative stress induced by 2,2'-azobis(2-methylpropionamidine) dihydrochloride (ABAP). After the in vivo treatments, the livers were collected to analyze the oxidative damage by thiol, and the antioxidant defense by catalase, superoxide dismutase, and glutathione peroxidase. In the HepG2 cells, the following probes were employed to assess the ROS production: dichlorofluorescein, MitoSOX, dihydroethidium, and Amplex Red. Rutin administered chronically improved the antioxidant defense in healthy animals, and when administered acutely both inhibited the increased production of ROS in HepG2 cells and improved the redox imbalance parameters in mice with induced oxidative stress. This study suggests rutin as a protective agent for restoration of hepatic redox homeostasis in redox injury induced by ABAP in Swiss mice and HelpG2 cells.

Phytomodulatory proteins isolated from Calotropis procera latex promote glycemic control by improving hepatic mitochondrial function in HepG2 cells

The medicinal uses of Calotropis procera are diverse, yet some of them are based on effects that still lack scientific support. Control of diabetes is one of them. Recently, latex proteins from C. procera latex (LP) have been shown to promote in vivo glycemic control by the inhibition of hepatic glucose production via AMP-activated protein kinase (AMPK). Glycemic control has been attributed to an isolated fraction of LP (CpPII), which is composed of cysteine peptidases (95%) and osmotin (5%) isoforms. Those proteins are extensively characterized in terms of chemistry, biochemistry and structural aspects. Furthermore, we evaluated some aspects of the mitochondrial function and cellular mechanisms involved in CpPII activity. The effect of CpPII on glycemic control was evaluated in fasting mice by glycemic curve and glucose and pyruvate tolerance tests. HepG2 cells was treated with CpPII, and cell viability, oxygen consumption, PPAR activity, production of lactate and reactive oxygen species, mitochondrial density and protein and gene expression were analyzed. CpPII reduced fasting glycemia, improved glucose tolerance and inhibited hepatic glucose production in control animals. Additionally, CpPII increased the consumption of ATP-linked oxygen and mitochondrial uncoupling, reduced lactate concentration, increased protein expression of mitochondrial complexes I, III and V, and activity of peroxisome-proliferator-responsive elements (PPRE), reduced the presence of reactive oxygen species (ROS) and increased mitochondrial density in HepG2 cells by activation of AMPK/PPAR. Our findings strongly support the medicinal use of the plant and suggest that CpPII is a potential therapy for prevention and/or treatment of type-2 diabetes. A common epitope sequence shared among the proteases and osmotin is possibly the responsible for the beneficial effects of CpPII.