4-hydroxy-2(3H)-benzoxazolone alleviates acetaminophen-induced hepatic injury by inhibiting NF-κB and activating Nrf2/HO-1 signaling pathways.

The purpose of this study is to evaluate the protective effect of 4-hydroxy-2(3H)-benzoxazolone from Acanthus ilicifolius (HBAI) on acute liver injury induced by acetaminophen in mice and its mechanism. Mice were continuously treated with HBAI (200, 100, 50 mg/kg) once a day for 10 days. After that, the mice were fasted for 8 hours, followed by intraperitoneal injection of acetaminophen (300 mg/kg). The results showed that HBAI pretreatment significantly reduced acetaminophen-induced liver tissue congestion, hepatocyte apoptosis and necrosis, and inflammatory cell infiltration. HBAI could effectively reduce the levels of serum alanine aminotransferase, aspartate aminotransferase, total bilirubin, reactive oxygen species and malondialdehyde. Interestingly, the activities of liver catalase, superoxide dismutase, glutathione and glutathione reductase were enhanced by HBAI pretreatment. Moreover, HBAI pretreatment alleviated acetaminophen-induced hepatocyte apoptosis by regulating the expression of Bcl-2 family proteins and the mitochondrial function. Further study showed that HBAI pretreatment effectively promoted the expression of Nrf2 and its signal downstream HO-1, NQO1, GCLC, GCLM, and MGST-1, suggesting the activation of the Nrf2/HO-1 signaling pathway. Meanwhile, HBAI attenuated the phosphorylation of NF-κBp65, IKKα/ß, and IκBα, as well as the expression of NF-κBp50, which indicated that HBAI blocked the signal transduction of NF-κB pathway. In conclusion, HBAI protects against acetaminophen-induced acute liver injury by inhibiting the NF-κB and activating Nrf2/HO-1 signaling pathways.

4-hydroxybenzo[d]oxazol-2(3H)-one ameliorates LPS/D-GalN-induced acute liver injury by inhibiting TLR4/NF-κB and MAPK signaling pathways in mice.

The purpose of this study was to synthesize 4-hydroxybenzo[d]oxazol-2(3H)-one (HBO) and to investigate its protective effects on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury. HBO (C7H5O3N) was synthesized based on 2-nitro-resorcinol and identified by physicochemical analysis. In the animal experiment, mice were pretreated with HBO (50, 100, 200 mg/kg) for 10 days. At the end of pretreatment, the animals were injected with LPS (10 µg/kg)/D-GalN (700 mg/kg). The results showed that HBO significantly alleviated liver injury induced by LPS/D-GalN in mice. It remarkably decreased inflammatory response by reducing the levels of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). Moreover, HBO notably attenuated hepatocyte apoptosis by inhibiting the release of Cytochrome C (Cyt C) from mitochondria into the cytoplasm and regulating the expression of B-cell lymphoma-2 (Bcl-2) family. Furthermore, the result showed that HBO inhibited the expressions of nuclear factor kappa-B p50 (NF-κBp50), toll-like receptor 4 (TLR4), and myeloid differentiation factor 88 (MyD88), as well as the phosphorylation of inhibitor of nuclear factor kappa-B (IκB), inhibitor of nuclear factor kappa-B kinase-α/ß (IKK-α/ß), nuclear factor kappa-B p65 (NF-κBp65), suggesting that HBO had a certain influence on the TLR4/NF-κB pathway. In addition, the mitogen-activated protein kinase (MAPK) signaling pathway was also affected by HBO, as evidenced by the decrease in the phosphorylation levels of extracellular regulated protein kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38). In conclusion, our study suggested that HBO could protect against LPS/D-GalN-induced liver injury, moreover, treatment with HBO appeared to be capable of further regulating the TLR4/NF-κB and MAPK signaling pathways.

HBOA ameliorates CCl4-incuded liver fibrosis through inhibiting TGF-ß1/Smads, NF-κB and ERK signaling pathways.

An ingredient was isolated from Acanthus ilicifolius and identified as 4-hydroxy-2(3H)-benzoxazolone (HBOA). Its protective effects and underlying mechanism on liver fibrosis were investigated. Briefly, rats were intragastrically administrated with 50% CCl4 twice a week for 12 weeks to induce liver fibrosis. Meanwhile, the animals were treated with various medicines from weeks 8 to 12. Then the histological change, serum biochemical index, inflammatory factors and hepatocyte apoptosis were detected. Moreover, the TGF-ß1/Smads, NF-κB and ERK signaling pathways were also detected to illustrate the underlying mechanism. The results showed that HBOA significantly ameliorated CCl4-induced liver injury and collagen accumulation in rats, as evidenced by the histopathologic improvement. Moreover, HBOA markedly decreased hepatocyte apoptosis by regulating the expression levels of caspase-3, -9 and -12, as well as the Bcl-2 family. The mechanism study showed that HBOA significantly decreased the expressions of α-smooth muscle actin (α-SMA) and collagen and inhibited the generation of excessive extracellular matrix (ECM) components by restoring the balance between matrix metalloproteinases (MMPs) and its inhibitor (TIMPs). HBOA markedly alleviated oxidative stress and inflammatory cytokines through inhibiting the NF-κB pathway. In addition, HBOA significantly down-regulated the levels of TGF-ß1, Smad2/3, Smad4 and up-regulated the level of Smad7, inhibiting the TGF-ß1/Smads signaling pathway. Moreover, HBOA significantly blocked the ERK signaling pathway, leading to the inactivation of hepatic stellate cells. This study suggests that HBOA exerts a protective effect against liver fibrosis via modulating the TGF-ß1/Smads, NF-κB and ERK signaling pathways, which will be developed as a potential agent for the treatment of liver fibrosis.