concanavalin-a and andrographolide

This study was designed to investigate the hepatic protective effect and the molecular mechanisms of andrographolide in concanavalin A-induced liver injury model. Results showed that andrographolide (Ag) attenuated concanavalin A (Con-A)-induced liver injury and inhibited hepatocyte apoptosis. Further results showed that oxidative stress response genes were significantly elevated during the pathogenesis induced by Con-A. Meanwhile, gadolinium chloride and N-acetyl-L-cysteine (NAC) treatment, which inactivates Kupffer cells or reduces reactive oxygen species, respectively, prevented the liver injury. So the messenger RNA levels of the oxidative response genes mentioned above were detected, and the following results showed that Ag treatment reduced their expression. Besides, serum lactate dehydrogenase and myeloperoxidase activity was significantly reduced by Ag. Finally, Ag treatment did not further reduce serum tumor necrosis factor-α production compared with NAC treatment alone. Thus, our results indicate that Ag prevents Con-A-induced liver injury and reduced the hepatic oxidative stress response. The hepatic protective effect of Ag indicates that Ag supplementation may be beneficial in the treatment of immune-mediated liver injury.

Topics: Animals; Apoptosis; Chemical and Drug Induced Liver Injury; Concanavalin A; Cyclooxygenase 2; Diterpenes; DNA Fragmentation; Glucose Transporter Type 1; Heme Oxygenase-1; Hepatocytes; Hypoxia-Inducible Factor 1, alpha Subunit; L-Lactate Dehydrogenase; Male; Mice; Mice, Inbred C57BL; Nitric Oxide Synthase Type II; Oxidative Stress; Peroxidase; Protective Agents; RNA, Messenger; Superoxide Dismutase; Superoxide Dismutase-1; Tumor Necrosis Factor-alpha

Andrographolide is the main labdane diterpene present in Andrographis paniculata. Two lines of evidence report immunostimulant and anti-inflammatory properties for andrographolide in different models. Using murine T-cells in vitro we demonstrated that andrographolide and to a lesser extent, 14-deoxyandrographolide (14-DAP), reduced significantly, in a dose-dependent manner, the IFN-gamma production induced by concanavaline A (CON-A), with an IC50 of 1.7 +/- 0.07 microM and 35.8 +/- 0.50 microM, respectively. Andrographolide, but not 14-DAP, inhibited partially the IL-2 production induced by CON-A. Andrographolide at doses of 5 and 10 microM reduced the extracellular-signal-regulated protein kinase (ERK1/2) phosphorylation induced by CON-A, whereas 14-DAP only reduced ERK1 and partially the ERK2 phosphorylation. The inhibition of ERK1/2 phosphorylation was associated to a decrease in the IFN-gamma production, due that UO126, a specific ERK1/2 inhibitor, also reduced the IFN-gamma production in murine T-cells induced by CON-A. Additionally, andrographolide and to a lesser extent 14-DAP, at doses of 50 microM and 100 microM, respectively, reduced the apoptosis induced by hydrocortisone and PMA in thymocytes, which was associated to a decrease in caspase-3 like activity. We conclude that both diterpenic labdanes isolated from A. paniculata can exert potent immunosuppressant effects without affecting the viability of the cells.

Topics: Andrographis; Animals; Apoptosis; Concanavalin A; Diterpenes; Dose-Response Relationship, Drug; Immunosuppressive Agents; Inhibitory Concentration 50; Interferon-gamma; Interleukin-2; Mice; Phytotherapy; Plant Extracts; T-Lymphocytes