Maslinic acid protects against lipopolysaccharide/d-galactosamine-induced acute liver injury in mice

Maslinic Acid: A New Compound for the Treatment of Multiple Organ Diseases

Maslinic acid (MA) is a pentacyclic triterpene acid, which exists in many plants, including olive, and is highly safe for human beings. In recent years, it has been reported that MA has anti-inflammatory, antioxidant, anti-tumor, hypoglycemic, neuroprotective and other biological activities. More and more experimental data has shown that MA has a good therapeutic effect on multiple organ diseases, indicating that it has great clinical application potential. In this paper, the extraction, purification, identification and analysis, biological activity, pharmacokinetics in vivo and molecular mechanism of MA in treating various organ diseases are reviewed. It is hoped to provide a new idea for MA to treat various organ diseases.

Recent Advances Regarding the Molecular Mechanisms of Triterpenic Acids: A Review (Part II)

Triterpenic acids are a widespread class of phytocompounds which have been found to possess valuable therapeutic properties such as anticancer, anti-inflammatory, hepatoprotective, cardioprotective, antidiabetic, neuroprotective, lipolytic, antiviral, and antiparasitic effects. They are a subclass of triterpenes bearing a characteristic lipophilic structure that imprints unfavorable in vivo properties which subsequently limit their applications. The early investigation of the mechanism of action (MOA) of a drug candidate can provide valuable information regarding the possible side effects and drug interactions that may occur after administration. The current paper aimed to summarize the most recent (last 5 years) studies regarding the MOA of betulinic acid, boswellic acid, glycyrrhetinic acid, madecassic acid, moronic acid, and pomolic acid in order to provide scientists with updated and accessible material on the topic that could contribute to the development of future studies; the paper stands as the sequel of our previously published paper regarding the MOA of triterpenic acids with therapeutic value. The recent literature published on the topic has highlighted the role of triterpenic acids in several signaling pathways including PI3/AKT/mTOR, TNF-alpha/NF-kappa B, JNK-p38, HIF-α/AMPK, and Grb2/Sos/Ras/MAPK, which trigger their various biological activities.

Chinese medicine in the treatment of autoimmune hepatitis: Progress and future opportunities

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease occurring in individuals of all ages with a higher incidence in females and characterized by hypergammaglobulinemia, elevated serum autoantibodies and histological features of interface hepatitis. AIH pathogenesis remains obscure and still needs in‐depth study, which is likely associated with genetic susceptibility and the loss of immune homeostasis. Steroids alone and in combination with other immunosuppressant agents are the primary choices of AIH treatment in the clinic, whereas, in some cases, severe adverse effects and disease relapse may occur. Chinese medicine used for the treatment of AIH has proven its merits over many years and is well tolerated. To better understand the pathogenesis of AIH and to evaluate the efficacy of novel therapies, several animal models have been generated to recapitulate the immune microenvironment of patients with AIH. In the current review, we summarize recent advances in the study of animal models for AIH and their application in pharmacological research of Chinese medicine‐based therapies and also discuss current limitations. This review aims to provide novel insights into the discovery of Chinese medicine‐originated therapies for AIH using cutting‐edge animal models.

Genome-Wide Identification of OSC Gene Family and Potential Function in the Synthesis of Ursane- and Oleanane-Type Triterpene in Momordica charantia

The triterpenes in bitter gourd (Momordica charantia) show a variety of medicinal activities. Oxidosqualene cyclase (OSC) plays an indispensable role in the formation of triterpene skeletons during triterpene biosynthesis. In this study, we identified nine genes encoding OSCs from bitter gourd (McOSC1-9). Analyses of their expression patterns in different tissues suggested that characteristic triterpenoids may be biosynthesized in different tissues and then transported. We constructed a hairy root system in which McOSC7 overexpression led to an increased accumulation of camaldulenic acid, enoxolone, and quinovic acid. Thus, the overexpression of McOSC7 increased the active components content in bitter gourd. Our data provide an important foundation for understanding the roles of McOSCs in triterpenoid synthesis.

Maslinic Acid Inhibits Cervical Intraepithelial Neoplasia by Suppressing Interleukin-6 and Enhancing Apoptosis in a Mouse Model

BACKGROUND

Cervical intraepithelial neoplasia (CIN) directly precedes cervical cancer, and elevated proinflammatory cytokine interleukins (IL)-6 is implicated in CIN.

OBJECTIVE

As maslinic acid exhibits anti-IL-6 property, the present study sought to determine the effect of maslinic acid on CIN in vitro and in vivo using cell cultures and mouse CIN models, respectively.

METHODS

The dose-effect of maslinic acid on HeLa cells, a human cervical cancer cell line, was first evaluated, including cytotoxicity, IL-6 secretion, IL-6 receptor (IL-6R) expression, proliferation potential and apoptosis status. A mouse model of CIN was also established, which was then subjected to increasing doses of maslinic acid treatment, followed by assessment of serum IL-6 level, cervical expression of IL-6R, and the proliferation potential and apoptosis of cervical tissues.

RESULTS

Maslinic acid dose-dependently inhibited cell growth and proliferation potential, reduced IL-6 secretion, cervical expression of IL-6R and induced apoptosis of HeLa cells in vitro. In the CIN mouse model, serum IL-6 level and cervical expression of IL-6R were elevated, which could be repressed by maslinic acid administration dose-dependently. Additionally, maslinic acid treatment in the CIN mice could also restore the otherwise increased proliferation potential and reduced apoptosis in the cervical tissues.

CONCLUSION

Maslinic acid exhibits potent anti-IL-6 property in the CIN mouse model, and alleviates the disease-related abnormality in proliferation potential and apoptosis state of the cervical tissue cells, demonstrating its usefulness as a promising agent in treating CIN.

Puerarin Prevents Acute Liver Injury via Inhibiting Inflammatory Responses and ZEB2 Expression

Puerarin, an isoflavone component extracted from herb radix puerariae, is widely used in China in the treatment of immune diseases and inflammation. Previous studies have demonstrated that puerarin prevented acute lung injury by regulating inflammatory responses. However, the effect of puerarin on acute liver injury (ALI) was unclear. The purpose of this study was to explore the beneficial effects of puerarin when applied to ALI. We found that puerarin inhibited liver injury and inflammatory cell infiltration in lipopolysaccharide (LPS)/D-galactose (D-Gal)-induced acute liver failure and the liver pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) in liver tissues with ALI and LPS-induced L-02 cells but upregulated the expression level of zinc finger E-box-binding homeobox 2 (ZEB2). Significantly, the results of this study showed that the inhibition of liver pro-inflammatory cytokine (IL-1β, IL-6, and TNF-α) production in LPS-induced L-02 cells was caused by ZEB2 overexpression. However, knocking down ZEB2 promoted LPS-mediated secretion of liver pro-inflammatory cytokines in L-02 cells. Additional experiments showed that puerarin inhibited the activation of the NF-κB signaling pathway by elevating ZEB2 expression in L-02 cells. In summary, puerarin most likely prevented activation of the pro-inflammatory factors and reduced LPS/D-Gal-induced liver injury by enhancing the ZEB2 expression level and, consequently, blocking activation of the NF-κB signaling pathway in the liver.

IL-6/STAT3 signaling activation exacerbates high fructose-induced podocyte hypertrophy by ketohexokinase-A-mediated tristetraprolin down-regulation

Glomerular hypertrophy is a crucial factor of severe podocyte damage and proteinuria. Our previous study showed that high fructose induced podocyte injury. The current study aimed to explore a novel molecular mechanism underlying podocyte hypertrophy induced by high fructose. Here we demonstrated for the first time that high fructose significantly initiated the hypertrophy in rat glomeruli and differentiated human podocytes (HPCs). Consistently, it induced inflammatory response with the down-regulation of anti-inflammatory factor zinc-finger protein tristetraprolin (TTP) and the activation of interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) signaling in these animal and cell models. Subsequently, high-expression of microRNA-92a-3p (miR-92a-3p) and its target protein cyclin-dependent kinase inhibitor p57 (P57) down-regulation, representing abnormal proliferation and apoptosis, were observed in vivo and in vitro. Moreover, high fructose increased ketohexokinase-A (KHK-A) expression in rat glomeruli and differentiated HPCs. Exogenous IL-6 stimulation up-regulated IL-6/STAT3 signaling and miR-92a-3p, reduced P57 expression and promoted podocyte proliferation, apoptosis and hypertrophy in vitro. The data from anti-inflammatory agent maslinic acid treatment or TTP siRNA transfection showed that high fructose may decrease TTP to activate IL-6/STAT3 signaling in podocyte overproliferation and apoptosis, causing podocyte hypertrophy. Whereas, KHK-A siRNA transfection remarkably restored high fructose-induced TTP down-regulation, IL-6/STAT3 signaling activation, podocyte overproliferation, apoptosis and hypertrophy in differentiated HPCs. Taken together, these results suggested that high fructose possibly increased KHK-A expression to down-regulate TTP, subsequently activated IL-6/STAT3 signaling to interfere with podocyte proliferation and apoptosis by up-regulating miR-92a-3p to suppress P57 expression, causing podocyte hypertrophy. Therefore, the inactivation of IL-6/STAT3 to relieve podocyte hypertrophy mediated by inhibiting KHK-A to increase TTP may be a novel strategy for high fructose diet-associated podocyte injury and proteinuria.

Advances in Research on the Preparation and Biological Activity of Maslinic Acid

Maslinic acid, a pentacyclic triterpene acid, is mainly isolated from olives. Maslinic acid and its derivatives exhibit a broad range of biological properties, such as anti-inflammatory, anticancer, anti-diabetic, antimicrobial, neuroprotective and hepatoprotective activities. In this minireview, the progress of research on maslinic acid with regard to its bioactivities, extraction, semisynthetic preparation and patents is reported. The relationships between the structure and the activity of maslinic acid and its derivatives are also discussed.

Sinapic acid ameliorates D-galactosamine/lipopolysaccharide-induced fulminant hepatitis in rats: Role of nuclear factor erythroid-related factor 2/heme oxygenase-1 pathways

BACKGROUND

Sinapic acid (SA) has been shown to have various pharmacological properties such as antioxidant, antifibrotic, anti-inflammatory, and anticancer activities. Its mechanism of action is dependent upon its ability to curb free radical production and protect against oxidative stress-induced tissue injuries.

AIM

To study the hepatoprotective effects of SA against lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver failure (ALF) in rats.

METHODS

Experimental ALF was induced with an intraperitoneal (i.p.) administration of 8 μg LPS and 800 mg/kg D-GalN in normal saline. SA was administered orally once daily starting 7 d before LPS/D-GalN treatment.

RESULTS

Data showed that SA ameliorates acute liver dysfunction, decreases serum levels of alanine transaminase (ALT), and aspartate aminotransferase (AST), as well as malondialdehyde (MDA) and NO levels in ALF model rats. However, pretreatment with SA (20 mg/kg and 40 mg/kg) reduced nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and levels of inflammatory cytokines (tumor necrosis factor-α and interleukin 6). Also, SA increased the activity of the nuclear factor erythroid-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathway.

CONCLUSION

In conclusion, SA offers significant protection against LPS/D-GalN-induced ALF in rats by upregulating Nrf2/HO-1 and downregulating NF-κB.

Paeonol derivative-6 attenuates inflammation by activating ZEB2 in acute liver injury

Paeonol is a natural phenolic compound and isolated as an active ingredient from Moutan Cortex. Paeonol derivative-6 (DPF-6) is a derivative of paeonol improved in water solubility and bioavailability. Previous studies have reported that paeonol possesses a variety of pharmacological activities, such as antioxidant and anti-inflammatory properties. Moreover, we have previously verified that DPF-6 has anti-inflammatory effects. However, the role and fundamental mechanism of DPF-6 in acute liver injury (ALI) was still unclear. In this study, we indicated that DPF-6 inhibited inflammation and the expression of TNF-α, IL-6 and IL-1β in liver tissues and LPS-mediated L-02 cells, concomitant with the upregulated expression of ZEB2. More importantly, it was demonstrated that overexpression of ZEB2 inhibited the expression level of TNF-α, IL-6 and IL-1β in LPS-mediated L-02 cells. In contrast, knockdown of ZEB2 increased the expression level of TNF-α, IL-6 and IL-1β in LPS-mediated L-02 cells. Further studies showed that ZEB2 inhibited the inflammation cytokine secretion via JNK signaling pathway in L-02 cells. Taken together, all the above results indicate that DPF-6 increased the expression of ZEB2, consequently inhibited inflammation cytokine secretion through JNK signaling pathway, which may be utilized as a potential anti-inflammation monomeric compound in the treatment of ALI.

Baicalein attenuates acute liver injury by blocking NLRP3 inflammasome

Infection and/or drug-mediated acute liver injury, the leading cause of lethal liver failure, is a critical health problem worldwide and lacks effective treatment. Here, we used Lipopolysaccharides (LPS)/D-galactosamine (D-gal)-treated primary hepatocytes to screen a natural library that contains 1130 chemicals. Baicalein in the library showed highest inhibitory effects against LPS/D-Gal-induced liver injury. In-vivo study similarly validated the protection of baicalein against dampened liver function and increased lethality after a challenge of LPS/D-Gal. Using a cytometric bead array, we found that IL-1α and IL-1β, the downstream of NLRP3, had highest reduction among the plasma inflammatory cytokines in LPS/D-Gal-challenged mice after a treatment of baicalein. To determine the target of baicalein and the underlying mechanism, Nlrp3^-/-, Gsdmd^-/- or WT mice were treated with or without baicalein, IL-1R antibody or recombinant mouse IL-1β (rmIL-1β) prior to a challenge of LPS/D-Gal. Deficiency of Nlrp3 or Gsdmd significantly restored LPS/D-Gal-induced acute liver injury and lethality, and further administration of baicalein did not have additive effects. In addition, the inhibition of the downstream by IL-1R antibody phenocopied the knockout of Nlrp3 or Gsdmd. Moreover, a challenge of rmIL-1β reversed the improvement in Nlrp3^-/- mice or the mice treated with baicalein. Taken together, NLRP3 functions as a pivotal promoter in acute liver injury and baicalein attenuates acute liver injury by inhibiting NLRP3 inflammasome.

Hepatoprotective effects of Camellia nitidissima aqueous ethanol extract against CCl4-induced acute liver injury in SD rats related to Nrf2 and NF-κB signalling

Context: Camellia nitidissima Chi (Theaceae) is an evergreen shrub, the leaves of which are used in many medicinal applications.Objective: To characterize the chemical composition of a 10% aqueous ethanol extract of C. nitidissima leaves (CNE), and to explore the protective effect of the extract against acute liver injury (ALI) in rats.Materials and methods: Male Sprague-Dawley rats were divided into six groups (n = 10): control and negative (0.5% CMC-Na, 5 mL/kg/d), thiopronin (20 mg/kg/d) and CNE (40, 80 and 160 mg/kg/d). All groups were treated for seven consecutive days, and then, except for the control, carbon tetrachloride was administered intraperitoneally. The biochemical parameters, mRNAs, and proteins were analyzed using enzyme-linked immunoassays kits, quantitative polymerase chain reaction and western blot. Chemical components were identified using mass spectroscopy, and the phenol and flavonoid content determined by ultraviolet spectrophotometry.Results: Pre-treatment with CNE (160 mg/kg) attenuated the pathological changes in liver tissues and decreased alanine transaminase (62 and 60%), aspartate transaminase (49 and 53%) and malondialdehyde (35 and 42%) levels in serum and liver tissues. Moreover, CNE reduced the concentrations of reactive oxygen species (55%), tumour necrosis factor-α (26%), interleukin-1β (19%) and IL-6 (19%) and blocked the nuclear translocation of p65. Pre-treatment with CNE increased anti-heme oxygenase-1 (40%), superoxide dismutase (108%) and glutathione (97%) levels through upregulating nuclear factor erythroid-2-related factor 2. Twelve compounds were detected; the content of phenols and flavonoids was determined as 34.474 ± 1.026 and 15.228 ± 0.422 mg/g crude drug in CNE, respectively.Discussion and conclusions: These results suggested that CNE is a promising agent for functional food and hepatoprotective drug against ALI.

S-allyl cysteine, an active ingredient of garlic, attenuates acute liver dysfunction induced by lipopolysaccharide/ d-galactosamine in mouse: Underlying mechanisms

In the present study, beneficial effect of S-allyl cysteine (SAC) was evaluated in the lipopolysaccharide/d-galactosamine (LPS/d-Gal) model of acute liver injury (ALI). To mimic ALI, LPS and d-Gal (50 μg/kg and 400 mg/kg, respectively) were intraperitoneally administered and animals received SAC per os (25 or 100 mg/kg/d) for 3 days till 1 hour before LPS/d-Gal injection. Pretreatment of LPS/d-Gal group with SAC-lowered activities of alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase and partially reversed inappropriate alterations of hepatic oxidative stress- and inflammation-related biomarkers including liver reactive oxygen species, malondialdehyde, and hepatic activity of the defensive enzyme superoxide dismutase, ferric reducing antioxidant power (FRAP), toll-like receptor-4 (TLR4), cyclooxygenase 2, NLR family pyrin domain containing 3 (NLRP3), caspase 1, nuclear factor κB (NF-κB), interleukin 1β (IL-1β), IL-6, tumor necrosis factor-α, and myeloperoxidase activity. Additionally, SAC was capable to ameliorate apoptotic biomarkers including caspase 3 and DNA fragmentation. In summary, SAC can protect liver against LPS/d-Gal by attenuation of neutrophil infiltration, oxidative stress, inflammation, apoptosis, and pyroptosis which is partly linked to its suppression of TLR4/NF-κB/NLRP3 signaling.

Ameliorative effect of urolithin A ond-gal-induced liver and kidney damage in aging miceviaits antioxidative, anti-inflammatory and antiapoptotic properties

Urolithin A, a metabolite produced by human colon microflora from ellagic acid and related compounds, has been reported to have antioxidant, anti-inflammatory and antiapoptotic properties. The present study investigates the protective effects of urolithin A (Uro A) on d-galactose (d-gal)-induced liver and kidney injury and the possible mechanisms in mice. In this study, we first investigated the antioxidant ability of Uro A in vitro. Then mice were treated with d-gal subcutaneously (150 mg kg⁻¹ d⁻¹), followed by Uro A at different dosages (50, 100, 150 mg kg⁻¹ d⁻¹, administered orally) for 8 weeks. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN) and creatinine (Cr) in the serum were tested. Histopathological features were assessed by hematoxylin and eosin (HE) staining followed by an assessment of the antioxidant and anti-inflammatory activities. Furthermore, we also evaluated the expression levels of the genes Bax, Bcl-2 and cleaved caspase-3 in the liver and kidney. The results showed that Uro A treatment obviously attenuated d-gal-induced liver and kidney damage. The beneficial effects of Uro A were accompanied by a decline in malondialdehyde (MDA) levels and a rise in the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and total antioxidant capacity (T-AOC) activity in the liver and kidney and downregulation of the levels of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6), in serum. Moreover, Uro A could modulate the expression of Bax, Bcl-2 and cleaved caspase-3 in the livers and kidneys of aging mice. These findings suggested that Uro A ameliorated d-gal-induced liver and kidney injury through attenuating oxidative stress, inflammatory responses and apoptosis.

Urolithin A, a metabolite produced by human colon microflora from ellagic acid and related compounds, has been reported to have antioxidant, anti-inflammatory and antiapoptotic properties.

Saikosaponin a ameliorates lipopolysaccharide and d‑galactosamine-induced liver injury via activating LXRα

Saikosaponin a (SSa), one of the major active components of Bupleurum falcatum, has antioxidant and anti-inflammatory pharmacological properties. However, the effects of SSa on liver injury have not been reported. In the present study, we evaluated the protective effects and mechanisms of SSa on lipopolysaccharide (LPS)/d‑galactosamine (D-GalN)-induced liver injury. The mice were pretreated with SSa 1 h before LPS/D-GalN treatment. The liver MPO, MDA, and the serum AST and ALT levels were tested by specific determination kits. The pro-inflammatory cytokines TNF-α and IL-1β were tested by ELISA kits. The expression of NF-κB signaling pathway and LXRα were tested by western blot analysis. The results showed that SSa significantly reduced the levels of liver MPO, MDA, and serum AST, ALT levels induced by LPS/D-GalN. SSa also dose-dependently inhibited LPS/D-GalN-induced pro-inflammatory cytokines TNF-α and IL-1β production. Furthermore, we found that SSa inhibited NF-κB signaling pathway activation induced by LPS/D-GalN. In addition, SSa dose-dependently increased the expression of LXRα. In conclusion, the results demonstrated that SSa had protective effect on liver injury and the anti-inflammatory mechanisms of SSa on LPS/D-GalN-induced liver injury may be due to its ability to increase LXRα expression. SSa might be a potential treatment for liver injury.

Amygdalin attenuates acute liver injury induced by D-galactosamine and lipopolysaccharide by regulating the NLRP3, NF-κB and Nrf2/NQO1 signalling pathways

Acute liver injury (ALI) is a life-threatening syndrome accompanied by overwhelming inflammation. Amygdalin (AGD) has been reported to possess various biological activities, particularly anti-inflammatory activity. The current study was designed to assess the protective effects and underlying mechanisms of AGD against ALI induced by d-galactosamine (GalN) and lipopolysaccharide (LPS) in mice. The results indicated that AGD treatment effectively reduced the lethality, ameliorated the histopathological liver changes, reduced the malondialdehyde (MDA) and myeloperoxidase (MPO) levels, and decreased the alanine transaminase (ALT) and aspartate aminotransferase (AST) levels resulting from LPS/GalN challenge. Moreover, AGD significantly inhibited LPS/GalN-induced inflammatory responses in mice with ALI by reducing not only the secretion of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 but also the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Additionally, our results demonstrated that the inhibitory effect of AGD was due to the suppressed activation of nuclear factor-kappa B (NF-κB) and nucleotide-binding domain (NOD-)like receptor protein 3 (NLRP3) inflammasome activity. Furthermore, AGD treatment substantially increased nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation and enhanced NAD (P) H: quinoneoxidoreductase 1 protein expression, which was reversed by a Nrf2 inhibitor, in HepG2 cells. In summary, our investigations suggested that the ability of AGD to ameliorate LPS/GalN-induced ALI may involve the inhibition of the NLRP3 inflammasome and NF-κB signalling pathways and the upregulation of the Nrf2/NQO1 signalling pathway.