Cajanus cajan ameliorated CCl4-induced oxidative stress in Wistar rats via the combined mechanisms of anti-inflammation and mitochondrial-membrane transition pore inhibition

Liver diseases is a public health issue in sub-saharan Africa and has been reported to be the major cause of many hospital admissions. Oxidative stress, mitochondrial dysfunction and inflammation play important roles in several diseases including liver injury. Cajanus cajan is an indigenous medicinal plant useful in the traditional treatment of jaundice, inflammation and liver injury.This study assessed the effects of methanol extract Cajanus cajan (MECC) on mitochondrial permeability transition (mPT) pore opening, biomarkers of oxidative stress and inflammation in CCl4-induced liver injury in rats.Wistar albino rats (200-210g) were completely randomized into five (5) groups of six animals each. Group I (control) was given distilled water orally once daily. Animals in group II were administered CCl4 in parafin (1:1) at a dose of 0.5 mL/kg i.p on the seventh day. Animals in groups III, IV and V were administered methanol extract of Cajanus cajan (MECC) at doses of 100, 200 mg/kg and silymarin (100 mg/kg) respectively for 7 days prior to a single intraperitoneal dose of CCl4. After 24 h of CCl4 treatment, serum and liver tissues were collected. Mitochondrial permeability transition (mPT) pore opening, mitochondrial ATPase activities and biomarkers of oxidative stress were determined spectrophotometrically. Tumor necrosis factor (TNFα), NF-κB and COX-2 were determined by immunohistochemistry and the phytochemicals present in the extract were determined by GC-MS.Liver enzyme (AST, ALP, ALT and γGT) activities and MDA levels were significantly decreased in rats pretreated with MECC at the dose of 100, 200 and silymarin (100 mg/kg) when compared to the rats administered CCl4 alone (p < 0.05). GSH, GST, CAT and SOD increased and the expressions of TNFα, NF-κB and COX- 2 were also reduced when compared to the CCl4- treated animals. In addition, the liver histopathological analyses revealed that MECC markedly alleviated inflammatory cell infiltration, hepatic fibrosis, hepatocyte ballooning, necrosis and severe apoptosis of hepatocytes induced by CCl4. GC-MS analysis yielded 23 compounds including flavonoids, terpenoids and fatty acids.Cajanus cajan leaf extract elicited hepatoprotective action on CCl4-induced liver injury via inhibition of mPT pore opening, prevention of CCl4-induced hepatic oxidative stress and suppression of inflammatory response thus it may become useful for chemoprevention of liver injury. This supports its traditional use.