D-galactosamine hepatotoxocity. V. Role of free fatty acids in the pathogenesis of fatty liver

Hepatoprotective effects of mushrooms

The particular characteristics of growth and development of mushrooms in nature result in the accumulation of a variety of secondary metabolites such as phenolic compounds, terpenes and steroids and essential cell wall components such as polysaccharides, β-glucans and proteins, several of them with biological activities. The present article outlines and discusses the available information about the protective effects of mushroom extracts against liver damage induced by exogenous compounds. Among mushrooms, Ganoderma lucidum is indubitably the most widely studied species. In this review, however, emphasis was given to studies using other mushrooms, especially those presenting efforts of attributing hepatoprotective activities to specific chemical components usually present in the mushroom extracts.

Mechanisms of Hepatoprotection ofTerminalia catappaL. Extract on D-Galactosamine-Induced Liver Damage

The hepatoprotective effects of the extract of Terminalia catappa L. leaves (TCE) against D-Galactosamine (D-GalN)-induced liver injury and the mechanisms underlying its protection were studied. In acute hepatic injury test, it was found that serum ALT activity was remarkably increased (3.35-fold) after injection of D-GalN in mice. But with oral pretreatment of TCE (20, 50 and 100 mg/kg/d) for 7 days, change in serum ALT was notably reversed. In primary cultured hepatocytes from fetal mice, it was found that cell viability was decreased by 45.0% after addition of D-GalN, while incubation with TCE (0.1, 0.5 and 1.0 mg/ml) for 36 hours could prevent the decrease in a dose-dependent manner. Meanwhile, D-GalN-induced both the increase of AST level (1.9-fold) and the decrease of SOD activity (48.0%) in supernatant of primary cultured hepatocytes could also be inhibited by pretreatment with TCE. In order to study the possible mechanisms underlying its hepatoprotective effects, one effective component separated from TCE, 2α, 3β,23-trihydroxyursane-12-en-28-oic acid (DHUA), was used to determine anti-mitochondrial swelling activity and superoxide radicals scavenging activity in vitro. It was found that at the concentration range of 50–500 μmol/L DHUA, Ca2+-induced mitochondrial swelling was dose-dependently inhibited, and superoxide radicals scavenging activity was also shown in a dose-dependent manner. It was concluded that TCE has hepatoprotective activity and the mechanisms underlying its protective effects may be related to the direct mitochondrion protection and strong scavenging activity on reactive oxygen species (ROS).

The anti-inflammatory and hepatoprotective effects of fractions from Cudrania cochinchinensis var. gerontogea

Various fractions of the ethanol extract from the root wood of Cudrania cochinchinensis var. gerontogea (Moraceae) were evaluated for their anti-inflammatory effects on carrageenan-induced edema and hepatoprotective activities on carbon tetrachloride (CCl4)-induced and D-galactosamine-(D-GalN) induced acute hepatotoxicity in rats. The fractions (n-hexane, CHCl3, EtOAc, n-BuOH, and H2O) displayed significant inhibitory activity against carrageenan-induced edema, and the active anti-inflammatory components were further localized in the n-BuOH fraction, which exhibited the greatest anti-inflammatory effect, an effect 5% greater than indomethacin (which was used as a standard reference substance). Each fraction exerted a significant hepatoprotective effect by reducing enzymatic alteration (sGOT and sGPT) and by improving hepatic lesions, including liver centrilobular inflammation, cell necrosis, fatty change, ballooning degeneration in CCl4-induced acute hepatitis; and necrosis of the portal area in D-GalN-induced acute liver injury. The n-BuOH and EtOAc fractions had the greatest hepatoprotective effects on CCl4-induced liver injury; in contrast, the CHCl3 fraction was most potent against D-GalN intoxication, which is comparable to silymarin, as a recognized hepatoprotective drug.

Modification of galactosamine-induced liver injury in rats by reticuloendothelial system stimulation or depression

The reticuloendothelial system has been implicated in galactosamine-induced liver injury because of a correlation between phagocytic alterations induced by colloidal carbon or endotoxin, and development of liver necrosis. To evaluate this concept, the influence of galactosamine on liver function and histology was determined in rats in which the reticuloendothelial system was normal, stimulated, or depressed. Methyl palmitate was used as a reticuloendothelial system suppressant, and glucan was used as a reticuloendothelial system activating agent. Administration of galactosamine to control rats resulted in hypoglycemia and increased serum bilirubin concentration, elevated serum glutamic oxalacetic transaminase, lactic dehydrogenase and glutamic pyruvic transaminase activities, and retention of sodium sulfobromophthalein. Histological studies revealed hepatic necrosis, and a polymorphonuclear and lymphocytic cellular infiltrate in galactosamine-treated rats. Pretreatment of rats with methyl palmitate inhibited galactosamine-induced alterations in serum glucose concentration, glutamic oxalacetic transaminase and lactic dehydrogenase activities, and sodium sulfobromophthalein retention. Liver necrosis and inflammatory reactions were also reduced in methyl palmitate-treated galactosamine-injected animals. In contrast, activation of the reticuloendothelial system by glucan increased galactosamine-induced alterations in serum bilirubin, glucose and cholesterol concentrations, glutamic oxalacetic transaminase, glutamic pyruvic transaminase and lactic dehydrogenase activities, and sodium sulfobromophthalein retention. Liver necrosis and inflammation were also increased. These findings suggest that the degree of galactosamine-induced liver injury is directly correlated with macrophage function when specific macrophage-modifying agents are used.