Protective effects of luteolin against acetaminophen-induced acute liver failure in mouse

Acetaminophen (APAP) is widely used as a safety analgesic and antipyretic agent. Although considered safe at therapeutic doses, overdose of APAP can cause acute liver injury that is sometimes fatal, requiring efficient pharmacological intervention. Luteolin is a naturally occurring flavonoid which is abundant in plants. The objective of this study was to investigate corresponding anti-oxidative and anti-inflammatory activities of luteolin, using acetaminophen-treated mice as a model system. Male C57BL/C mice were randomly divided into three groups (n=6 each). The control group was given phosphate buffered saline (PBS) orally. The APAP group was given APAP by intraperitoneal injection (i.p) at 300 mg/kg suspended in PBS. The luteolin-treated group was given APAP and luteolin (0-100 mg/kg/day, 1 or 3 days before APAP administration) suspended in PBS orally. 16 h after APAP administration, the liver and serum were collected to determine the liver injury. Luteolin administration significantly decreased acetaminophen-induced serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), malondialdehyde (MDA) levels, as well as glutathione (GSH) depletion and decrease of superoxide dismutase (SOD). Luteolin restored SOD, GSH and GSH-px activities and depressed the expression of pro-inflammatory factors, such as inducible nitric oxide synthase (i-NOS), TNF-α, nuclear factor kappa B (NF-κB), and IL-6, respectively. Moreover, luteolin down-regulated acetaminophen-induced nitrotyrosine (NT) formation and endoplasmic reticulum (ER) stress. These results suggest the presence of anti-oxidative, anti-inflammatory and anti-ER stress properties of luteolin in response to acetaminophen-induced liver injury in mice.