Ursolic acid reduces oxidative stress injury to ameliorate experimental autoimmune myocarditis by activating Nrf2/HO-1 signaling pathway

Health position paper and redox perspectives - Bench to bedside transition for pharmacological regulation of NRF2 in noncommunicable diseases

Nuclear factor erythroid 2-related factor 2 (NRF2) is a redox-activated transcription factor regulating cellular defense against oxidative stress, thereby playing a pivotal role in maintaining cellular homeostasis. Its dysregulation is implicated in the progression of a wide array of human diseases, making NRF2 a compelling target for therapeutic interventions. However, challenges persist in drug discovery and safe targeting of NRF2, as unresolved questions remain especially regarding its context-specific role in diseases and off-target effects. This comprehensive review discusses the dualistic role of NRF2 in disease pathophysiology, covering its protective and/or destructive roles in autoimmune, respiratory, cardiovascular, and metabolic diseases, as well as diseases of the digestive system and cancer. Additionally, we also review the development of drugs that either activate or inhibit NRF2, discuss main barriers in translating NRF2-based therapies from bench to bedside, and consider the ways to monitor NRF2 activation in vivo.

Synthesis and potential anti-inflammatory response of indole and amide derivatives of ursolic acid in LPS-induced RAW 264.7 cells and systemic inflammation mice model: Insights into iNOS, COX2 and NF-κB

Ursolic acid (3-hydroxy-urs-12-ene-28-oic acid, UA) is a pentacyclic triterpene present in numerous plants, fruits and herbs and exhibits various pharmacological effects. However, UA has limited clinical applicability since it is classified as BCS class IV molecule, characterized by low solubility, low oral bioavailability and low permeability. In the present study, UA was isolated from the biomass marc of Lavandula angustifolia and was structurally modified by an induction of indole ring at the C-3 position and amide group at the C-17 position with the aim to enhance its pharmacological potential. This modification resulted in the synthesis of a series of compounds which were investigated for their anti-inflammatory potential both in-vitro and in animal models in comparison to UA. In RAW 264.7 cells, UA and its derivatives were non-cytotoxic up to 10 µM. The derivative UA-1 exhibited a significantly lower IC50 (2.2 ± 0.4 µM) for NO inhibition compared to UA (17.5 ± 2.0 µM). Molecular docking showed strong interactions of UA-1 with TNF-α and NF-κB. UA-1 significantly reduced LPS-induced pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) in RAW 264.7 macrophages with the inhibition levels of 74.2 ± 2.1 % for TNF-α, 55.9 ± 3.7 % for IL-6 and 59.7 ± 4.2 % for IL-1β at 5.0 µM, respectively and reactive oxygen species while upregulating anti-inflammatory cytokine, IL-10. It also downregulated iNOS, COX-2, p-NF-κB p65, and p-IκBα at both mRNA and protein levels. In LPS-induced systemic inflammation mice model, UA-1 significantly lowered NO, TNF-α, IL-6, IL-1β and serum biochemical parameters, reduced tissue damage, and exhibited improved aqueous solubility and moderate lipophilicity. Overall, UA-1 demonstrated superior anti-inflammatory potential, improved solubility, and better therapeutic potential compared to UA.

Effects of ursolic acid on growth performance, serum biochemistry, antioxidant capacity, and intestinal health of broilers

Previous studies have shown that adding 450 mg/kg of ursolic acid (UA) can improve the growth performance of broilers. However, the specific mechanism is still unclear. Therefore, the purpose of this study was to further explore whether UA promotes the growth of broilers by affecting the intestinal environment of broilers. We randomly divided 120 broilers with similar BW (46.53 ± 0.05 g) into two groups. Each group had six replicates, with 10 broilers per replicate. The broilers were fed either the corn-soybean meal-basal diet (CON group) or the corn-soybean meal-basal diet supplemented with 450 mg/kg UA (UA group). This study lasted 42 days. Adding UA increased the daily weight gain and feed conversion ratio of broilers (P < 0.05). The UA group exhibited reduced aspartate aminotransferase, total cholesterol, interleukin 6 and interleukin 1, and triacylglycerol levels, with increased interleukin 10 and high-density lipoprotein cholesterol in serum (P < 0.05). The UA supplementation improved total antioxidant capacity, total superoxide dismutase, and glutathione peroxidase activity in serum (P < 0.05), and increased these levels in the jejunum (P < 0.05). It reduced malondialdehyde concentration in the jejunum and ileum (P < 0.05), improved jejunal morphology by increasing villus height and villus-to-crypt ratio, and decreased crypt depth (P < 0.05). Gene expression of zona occludens 1 and Claudin-1 was higher, while interleukin 6 was lower in the UA group (P < 0.05). Additionally, interleukin 10 gene expression in jejunal mucosa was higher (P < 0.05). Significant differences were observed in the abundance of Bacteroides, proteobacteria, and desulfurisation bacteria (P < 0.05), with higher Barnesiella and Clostridia_UCG-014, and lower Romboutsia in the UA group (P < 0.05). Barnesiella negatively correlated with interleukin 6, interleukin 1, and triacylglycerol, but positively correlated with interleukin 10 (P < 0.05). In conclusion, adding 450 mg/kg UA to broiler feed can improve serum and jejunal antioxidant capacity, reduce jejunal and ileal inflammation, improve jejunal morphology, and regulate caecal microbiota structure composition, promoting broiler growth.

Mechanistic Insights on Cardioprotective Properties of Ursolic Acid: Regulation of Mitochondrial and Non-mitochondrial Pathways

Ursolic acid, a natural pentacyclic triterpenoid compound, has been shown to have significant cardioprotective effects in various preclinical studies. This article reviews the various mechanisms by which ursolic acid achieves its cardioprotective effects, highlighting its potent anti-oxidant, anti-inflammatory, and anti- apoptotic properties. Ursolic acid upregulates anti-oxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx), effectively reducing oxidative stress, thereby decreasing reactive oxygen species (ROS) and improving lipid peroxidation levels. Furthermore, ursolic acid downregulates pro-inflammatory cytokines and inhibits key inflammatory pathways, such as nuclear factor kappa B (NF-κB), which results in its anti-inflammatory effects. These actions help in protecting cardiac tissues from acute and chronic inflammation. Ursolic acid also promotes mitochondrial function and energy metabolism by enhancing mitochondrial biogenesis and reducing dysfunction, which is critical during ischemia-reperfusion (I/R) injury. Additionally, ursolic acid influences multiple molecular pathways, including B-cell leukemia/lymphoma 2 protein (Bcl- 2)/Bcl-2 associated x-protein (Bax), miR-21/extracellular signal-regulated kinase (ERK), and phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), to reduce cardiomyocyte apoptosis. Collectively, these properties make ursolic acid a promising therapeutic agent for cardiovascular diseases (CVDs), warranting further research and clinical trials to harness its potential fully.

Assessment of ursolic acid effect on in vitro model of cardiac fibrosis

This study aimed to evaluate the effects of ursolic acid (UA) on Angiotensin II (Ang II)-treated neonatal rat cardiac fibroblasts (rCFs) as an in vitro model of cardiac fibrosis. The rCFs were isolated from two-day-old neonatal rats. An in vitro model of cardiac fibrosis was established using 500 nm Ang II treatment for 48 h. The cells were then treated with 5 and 10 μM of UA for 24 and 48 h. Masson's trichrome staining, hydroxyproline content assay, scratch assay, apoptosis assay, measurements of superoxide dismutase (SOD) and malondialdehyde (MDA) levels, real-time PCR, immunocytology and western blotting, were employed to assess the impact of UA. Ang II induced fibrosis in rCFs, as evidenced by the examination of various fibrotic markers. Upon treatment with 5 and 10 μM of UA, the amount of fibrosis in Ang II-treated rCFs was significantly decreased, so that the hydroxyproline concentration was reduced to 0.3 and 0.7 times, respectively. The RNA expression of the Col1a1, Col3a1, Tgfb1, Acta2 and Mmp2 genes had a decrease as well as Nrf2 and HO-1 had an increase after UA treatment. UA could lessen the harmful effects of cardiac fibrosis in a dose- and time-dependent manner, due to its antiapoptotic, antioxidant and cardioprotective properties. This suggests the potential of UA for treatment of cardiac fibrosis.

Ursolic Acid Regulates Immune Balance, Modulates Gut Microbial Metabolism, and Improves Liver Health in Mice

Ursolic acid (UA) has demonstrated significant immunomodulatory and hepatoprotective effects; however, the underlying mechanisms remain unclear. This study aims to analyze the impact of UA on the gut microbiome, metabolome, and liver transcriptome, investigate UA's role in maintaining gut immune homeostasis and liver health, and evaluate the potential contributions of gut microbes and their metabolites to these beneficial effects. Our findings indicate that UA enhances immune balance in the jejunum, fortifies intestinal barrier function, and promotes overall gut health. UA modulates the intestinal microbiota and its metabolic processes, notably increasing the abundance of beneficial bacteria such as Odoribacter and Parabacteroides, along with their metabolites, including ornithine and lactucin. Additionally, UA inhibits the expression of interleukin-1 receptor 1 (IL1R1) and calcium (Ca2+) voltage-gated channel auxiliary subunit beta 2 (CACNB2) while enhancing the synthesis pathways of retinol and ascorbic acid, thereby exerting a protective influence on liver function. In summary, UA enhances intestinal immune homeostasis and promotes liver health, with these advantageous effects potentially mediated by beneficial bacteria (Odoribacter and Parabacteroides) and their metabolites (ornithine and lactucin).

Antioxidant Carbon Dots and Ursolic Acid Co-Encapsulated Liposomes Composite Hydrogel for Alleviating Adhesion Formation and Enhancing Tendon Healing in Tendon Injury

Background

The formation of adhesion after tendon injury represents a major obstacle to tendon repair, and currently there is no effective anti-adhesion method in clinical practice. Oxidative stress, inflammation, and fibrosis can occur in tendon injury and these factors can lead to tendon adhesion. Antioxidant carbon dots and ursolic acid (UA) both possess antioxidant and anti-inflammatory properties. In this experiment, we have for the first time created RCDs/UA@Lipo-HAMA using red fluorescent carbon dots and UA co-encapsulated liposomes composite hyaluronic acid methacryloyl hydrogel. We found that RCDs/UA@Lipo-HAMA could better attenuate adhesion formation and enhance tendon healing in tendon injury.

Materials and Methods

RCDs/UA@Lipo-HAMA were prepared and characterized. In vitro experiments on cellular oxidative stress and fibrosis were performed. Reactive oxygen species (ROS), and immunofluorescent staining of collagens type I (COL I), collagens type III (COL III), and α-smooth muscle actin (α-SMA) were used to evaluate anti-oxidative and anti-fibrotic abilities. In vivo models of Achilles tendon injury repair (ATI) and flexor digitorum profundus tendon injury repair (FDPI) were established. The major organs and blood biochemical indicators of rats were tested to determine the toxicity of RCDs/UA@Lipo-HAMA. Biomechanical testing, motor function analysis, immunofluorescence, and immunohistochemical staining were performed to assess the tendon adhesion and repair after tendon injury.

Results

In vitro, the RCDs/UA@Lipo group scavenged excessive ROS, stabilized the mitochondrial membrane potential (ΔΨm), and reduced the expression of COL I, COL III, and α-SMA. In vivo, assessment results showed that the RCDs/UA@Lipo-HAMA group improved collagen arrangement and biomechanical properties, reduced tendon adhesion, and promoted motor function after tendon injury. Additionally, the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) in the RCDs/UA@Lipo-HAMA group increased; the levels of cluster of differentiation 68 (CD68), inducible Nitric Oxide Synthase (iNOS), COL III, α-SMA, Vimentin, and matrix metallopeptidase 2 (MMP2) decreased.

Conclusion

In this study, the RCDs/UA@Lipo-HAMA alleviated tendon adhesion formation and enhanced tendon healing by attenuating oxidative stress, inflammation, and fibrosis. This study provided a novel therapeutic approach for the clinical treatment of tendon injury.

Protective effects of METRNL overexpression against pathological cardiac remodeling

At present, meteorin-like protein (METRNL) has been proven to be widely expressed in the myocardium and participates in the pathogenic process of various cardiovascular diseases. However, the effects of METRNL on pathological cardiac hypertrophy is still unknown. In the present study, we used a mouse model of transverse aortic constriction (TAC) surgery to mimic pathological cardiac hypertrophy and gene delivery system to overexpress METRNL in vivo. The results showed that METRNL overexpression improved TAC-induced pathological cardiac hypertrophy in mice and neonatal cardiomyocytes. In addition, METRNL overexpression diminished TAC-induced cardiac oxidative damage, inflammation and cardiomyocyte apoptosis. Moreover, the cardioprotective effect of METRNL overexpression was directly related to the activation of AMP-activated protein kinase (AMPK) and sirtuin1 (SIRT1). In summary, our data identified that METRNL may be a promising therapeutic target to mitigate pathological cardiac hypertrophy in the future.

Omaveloxolone ameliorates isoproterenol-induced pathological cardiac hypertrophy in mice

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important transcriptional regulator that plays a protective role against various cardiovascular diseases. Omaveloxolone is a newly discovered potent activator of Nrf2 that has a variety of cytoprotective functions. However, the potential role of omaveloxolone in the process of pathological cardiac hypertrophy and heart failure are still unknown. In this study, an isoproterenol (ISO)-induced pathological cardiac hypertrophy model was established to investigate the protective effect of omaveloxolone in vivo and in vitro. Our study first confirmed that omaveloxolone administration improved ISO-induced pathological cardiac hypertrophy in mice and neonatal cardiomyocytes. Omaveloxolone administration also diminished ISO-induced cardiac oxidative stress, inflammation and cardiomyocyte apoptosis. In addition, omaveloxolone administration activated the Nrf2 signaling pathway, and Nrf2 knockdown almost completely abolished the cardioprotective effect of omaveloxolone, indicated that the cardioprotective effect of omaveloxolone was directly related to the activation of the Nrf2 signaling. In summary, our study identified that omaveloxolone may be a promising therapeutic agent to mitigate pathological cardiac hypertrophy.

Phytochemistry and Pharmacology of Eleutherococcus sessiliflorus (Rupr. & Maxim.) S.Y.Hu: A Review

Eleutherococcus sessiliflorus (Rupr. & Maxim.) S.Y.Hu (E. sessiliflorus), a member of the Araliaceae family, is a valuable plant widely used for medicinal and dietary purposes. The tender shoots of E. sessiliflorus are commonly consumed as a staple wild vegetable. The fruits of E. sessiliflorus, known for their rich flavor, play a crucial role in the production of beverages and fruit wines. The root barks of E. sessiliflorus are renowned for their therapeutic effects, including dispelling wind and dampness, strengthening tendons and bones, promoting blood circulation, and removing stasis. To compile a comprehensive collection of information on E. sessiliflorus, extensive searches were conducted in databases such as Web of Science, PubMed, ProQuest, and CNKI. This review aims to provide a detailed exposition of E. sessiliflorus from various perspectives, including phytochemistry and pharmacological effects, to lay a solid foundation for further investigations into its potential uses. Moreover, this review aims to introduce innovative ideas for the rational utilization of E. sessiliflorus resources and the efficient development of related products. To date, a total of 314 compounds have been isolated and identified from E. sessiliflorus, encompassing terpenoids, phenylpropanoids, flavonoids, volatile oils, organic acids and their esters, nitrogenous compounds, quinones, phenolics, and carbohydrates. Among these, triterpenoids and phenylpropanoids are the primary bioactive components, with E. sessiliflorus containing unique 3,4-seco-lupane triterpenoids. These compounds have demonstrated promising properties such as anti-oxidative stress, anti-aging, antiplatelet aggregation, and antitumor effects. Additionally, they show potential in improving glucose metabolism, cardiovascular systems, and immune systems. Despite some existing basic research on E. sessiliflorus, further investigations are required to enhance our understanding of its mechanisms of action, quality assessment, and formulation studies. A more comprehensive investigation into E. sessiliflorus is warranted to delve deeper into its mechanisms of action and potentially expand its pharmaceutical resources, thus facilitating its development and utilization.