Taraxasterol from Taraxacum prevents concanavalin A-induced acute hepatic injury in mice via modulating TLRs/NF-κB and Bax/Bc1-2 signalling pathways

Abstract

Immune hepatic injury is a liver disease closely related to an immune imbalance of T cells and macrophages. Our previous series of studies have demonstrated that taraxasterol isolated from Taraxacum possesses great anti-inflammatory and immunomodulatory effects in vivo and in vitro. In this study, we explored the preventive effects of taraxasterol and its underlying mechanisms on concanavalin A (Con A)-induced acute hepatic injury in mice. It was found that treatment with taraxasterol significantly decreased the Con A-induced increase of liver index, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and hepatic malondialdehyde (MDA) levels, and increased the Con A-induced decrease of hepatic glutathione (GSH) and superoxide dismutase (SOD) production. Taraxasterol also significantly inhibited the release of pro-inflammatory cytokines tumour necrosis factor-a (TNF-a), interleukin-6 (IL-6), IL-1b, interferon-c (IFN-c) and IL-4. In addition, treatment with taraxasterol alleviated the hepatic histopathological injury and apoptosis induced by Con A. Furthermore, taraxasterol dramatically down-regulated the expressions of T toll-like receptor (TLR2), TLR4 and nuclear factor-jappaB (NF-jB) p65, and decreased the expression ratio of Bax/Bc1-2 in hepatic tissues. These findings suggest that taraxasterol prevents Con A-induced acute hepatic injury in mice by inhibiting TLRs/NF-jB inflammatory signalling pathway and promoting Bax/Bc1-2 anti-apoptotic signalling pathway.

In vitro inhibition effects of hepatitis B virus by dandelion and taraxasterol

“…Maybe there are other antiviral mechanisms. New evidences show that dandelion extracts improve immune responses [44,45].Taraxasterol possesses immunomodulatory effects to prevent acute hepatic injury [46]. The dysfunction of innate immune cells and adaptive immune cells is a critical factor, which leads to virus clearance failure [47].…”

Summary of Natural Products Ameliorate Concanavalin A-Induced Liver Injury: Structures, Sources, Pharmacological Effects, and Mechanisms of Action

“…Taraxasterol, resulted in a major downregulation in TLR2, TLR4, and NF-κB p65 expression and decreased the Bax/Bc1-2 expression ratio in hepatic tissues. Accordingly, taraxasterol prevented Con A-related liver damage by inhibition of the TLRs/NF-κB signaling pathway and promoting Bax/Bc1-2 anti-apoptotic signaling pathway [48].…”

A comprehensive review of the benefits of Taraxacum officinale on human health

“…Previous studies found that Taraxacum officinale extract improves immunity, increasing nitric oxide (NO) and cytokines production in mice (Kim et al 1998;Lee et al 2012). Another study showed that taraxasterol can activate the Bax/Bc1-2 anti-apoptotic signalling pathway, which is downregulated in autoimmune disorders (Sang et al 2019). A study by Tan et al (2017) found that Taraxacum officinale extracts ameliorate the immune response in vivo (Table 1).…”