Patchouli oil isolated from the leaves of Pogostemon cablin ameliorates ethanol-induced acute liver injury in rats via inhibition of oxidative stress and lipid accumulation

Abstract

Excessive alcohol consumption can cause serious hepatic injury which is associated with oxidative stress and fatty metabolic disturbance. Patchouli oil (PO) is a sort of food supplement with high medicinal value in hepatoprotection, but its ability against ethanol-induced liver failure has not been demonstrated. Thus, this study aimed to investigate the potential hepatoprotection of PO through an ethanol-induced hepatotoxicity rat model. Our results showed that PO pretreatment could dramatically decrease the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in serum, paralleled by an improvement of histopathology alterations. Additionally, PO could markedly suppress the content of reactive oxygen species (ROS), tumor necrosis factor alpha (TNF-α), free fatty acid (FFA), and triglyceride (TG), while enhancing the activities of glutathione (GSH), glutathione reductase (GR), and superoxide dismutase (SOD) as well as the ratio of glutathione to oxidized glutathione (GSH/GSSG) in liver. The protective effect of PO against oxidative stress was interrelated with restraining the mRNA and protein expression of hepatic microsomal enzyme cytochrome P450 2E1 (CYP2E1). What's more, PO pretreatment could also accelerate lipometabolism via up-regulating expressions of adenosine monophosphate-activated protein kinase (AMPK), peroxisome proliferator-activated receptor α (PPAR-α), and carnitine palmitoyltransferase 1 (CPT-1) and down-regulating expressions of nuclear factor-kappaB (NF-κB) p65, sterol regulatory element-binding protein 1 (SREBP-1c), fatty acid synthase (FAS), and stearoyl-CoA desaturase 1 (SCD-1). To conclude, PO showed potent effect against ethanol-induced hepatotoxicity by relieving oxidative stress and preventing lipid accumulation.

Fig. 1. GC-MS analysis of patchouli oil. Numbers indicated on peaks corresponded to those in Table 1.

Fig. 2. Effects of PO on levels of ALT, AST, ALP and LDH in liver. (A) ALT; (B) AST; (C) ALP; (D) LDH. Values were presented as the mean ± SD (n = 12). ^##p < 0.01 vs. NC group; *p < 0.05, **p < 0.01 vs. Model group.

Fig. 3. Effects of PO on histological evaluation in ethanol-induced liver damage (H&E staining, magnification 200×). (A) NC group: visible central veins and thin sinusoids; (B) alcohol Model group: severe liver damage, inflammatory infiltration and necrosis; (C) alcohol + silymarin group; (D) alcohol + PO 100 mg kg⁻¹; (E) alcohol + PO 200 mg kg⁻¹; (F) alcohol + PO 400 mg kg⁻¹: well-formed hepatocytes and minor histopathology change. Arrows indicated both apparent focal necrosis and inflammatory infiltration.

Fig. 4. Effects of PO on antioxidant ability and hepatic lipidosis levels of GSH, GSH/GSSG, GR, SOD and TG in liver. (A) GSH; (B) GSH/GSSG; (C) GR; (D) SOD; (E) TG. Values were presented as the mean ± SD (n = 12). ^##p < 0.01 vs. NC group; **p < 0.01 vs. Model group.

Fig. 5. Effects of PO on levels of ROS, TNF-α and FFA in liver. (A) ROS; (B) TNF-α; (C) FFA. Values were presented as the mean ± SD (n = 12). ^##p < 0.01 vs. NC group; *p < 0.05, **p < 0.01 vs. Model group.

Fig. 6. Effects of PO on the transcriptional levels of (A) AMPK, (B) PPAR-α and (C) CPT-1 in liver. Values were presented as the mean ± SD (n = 12). ^##p < 0.01 vs. NC group; *p < 0.05, **p < 0.01 vs. Model group.

Fig. 7. Effects of PO on the transcriptional levels of (A) CYP2E1, (B) NF-κB p65, (C) SREBP-1c, (D) SCD-1 and (E) FAS in liver. Values were presented as the mean ± SD (n = 12). ^##p < 0.01 vs. NC group; *p < 0.05, **p < 0.01 vs. Model group.

Fig. 8. Effect of PO on protein expression of (A) AMPK, (B) PPAR-α and (C) CPT-1. Values were presented as the mean ± SD. ^#p < 0.05, ^##p < 0.01 vs. NC group; *p < 0.05, **p < 0.01 vs. Model group.

Fig. 9. Effect of PO on protein expression of (A) CYP2E1, (B) NF-κB p65, (C) SREBP-1c, (D) SCD-1 and (E) FAS. Values were presented as the mean ± SD. ^##p < 0.01 vs. NC group; *p < 0.05, **p < 0.01 vs. Model group.