Kirenol exerts a potent anti-arthritic effect in collagen-induced arthritis by modifying the T cells balance

Research progress in arthritis treatment with the active components of Herba siegesbeckiae

Arthritis is a group of diseases characterized by joint pain, swelling, stiffness, and limited movement. Osteoarthritis, rheumatoid arthritis, and gouty arthritis are the most common types of arthritis. Arthritis severely affects the quality of life of patients and imposes a heavy financial and medical burden on their families and society at large. As a widely used traditional Chinese medicine, Herba siegesbeckiae has many pharmacological effects such as anti-inflammatory and analgesic, anti-ischemic injury, cardiovascular protection, and hypoglycemic. In addition, it has significant therapeutic effects on arthritis. The rich chemical compositions of H. siegesbeckiae primarily include diterpenoids, sesquiterpenoids, and flavonoids. As one of the main active components of H. siegesbeckiae, kirenol and quercetin play a vital role in reducing arthritis symptoms. In the present study, the research progress in arthritis treatment with the active components of H. siegesbeckiae is reviewed.

Therapeutic effects of Siegesbeckia orientalis L. and its active compound luteolin in rheumatoid arthritis: network pharmacology, molecular docking and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis (RA) is a common difficult disease with a high disability rate. Siegesbeckia orientalis L. (SO), a Chinese medicinal herb that is commonly used for treating RA in clinical practice. While, the anti-RA effect and the mechanisms of action of SO, as well as its active compound(s) have not been elucidated clearly.

AIM OF THE STUDY

We aim to explore the molecular mechanism of SO against RA by using network pharmacology analysis, as well as the in vitro and in vivo experimental validations, and to explore the potential bioactive compound(s) in SO.

METHODS

Network pharmacology is an advanced technology that provides us an efficient way to study the therapeutic actions of herbs with the underlying mechanisms of action delineated. Here, we used this approach to explore the anti-RA effects of SO, and then the molecular biological approaches were used to verify the prediction. We first established a drug-ingredient-target-disease network and a protein-protein interaction (PPI) network of SO-related RA targets, followed by the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Further, we used lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and vascular endothelial growth factor-A (VEGFA)-induced human umbilical vein endothelial cell (HUVEC) models, as well as adjuvant-induced arthritis (AIA) rat model to validate the anti-RA effects of SO. The chemical profile of SO was also determined by using the UHPLC-TOF-MS/MS analysis.

RESULTS

Network pharmacology analysis highlighted inflammatory- and angiogenesis-related signaling pathways as promising pathways that mediate the anti-RA effects of SO. Further, in both in vivo and in vitro models, we found that the anti-RA effect of SO is at least partially due to the inhibition of toll like receptor 4 (TLR4) signaling. Molecular docking analysis revealed that luteolin, an active compound in SO, shows the highest degree of connections in compound-target network; moreover, it has a direct binding to the TLR4/MD-2 complex, which is confirmed in cell models. Besides, more than forty compounds including luteolin, darutoside and kaempferol corresponding to their individual peaks were identified tentatively via matching with the empirical molecular formulae and their mass fragments.

CONCLUSION

We found that SO and its active compound luteolin exhibit anti-RA activities and potently inhibit TLR4 signaling both in vitro and in vivo. These findings not only indicate the advantage of network pharmacology in the discovery of herb-based therapeutics for treating diseases, but also suggest that SO and its active compound(s) could be developed as potential anti-RA therapeutic drugs.

Ent-16β,17-dihydroxy-kauran-19-oic acid (DKA), a kaurane diterpenoid from Sigesbeckia pubescens(Makino) Makino, inhibits the migration of MDA-MB-231 breast cancer

Ent-kaurane diterpenoids were studied as a biologically active ingredient group of Sigesbeckia pubescens (Makino) Makino. Here, five known ent-kaurane diterpenoids were isolated and identified, named ent-16β,17-dihydroxy-kauran-19-oic acid (1), ent-16β,17-dihydroxy-kauran-19-oate (2), ent-18-acetoxy-17-hydroxykauran-19-oic acid (3), ent-16β,17,18-trihydroxy-kauran-19 -oic acid (4), and ent-17-hydroxy-kauran-16βH-19-oic acid (5). Their inhibitory effects of these compounds on MDA-MB-231 breast cancer migration were firstly tested in a chemotaxis invasion assay. Among them, compound 1 (DKA) showed superior inhibitory activities with IC50 value of 1.96 µM. Then, a wound healing assay and BALB/c nude mice were used for further studying the inhibitory activity of DKA on MDA-MB-231 breast cancer migration in vitro and in vivo, respectively. The wound healing assay showed that DKA (1, 5, and 25 μM) can significantly inhibit cell migration and the mouse model of lung metastasis showed that DKA (2.5, 5, and 10 mg/kg) could strongly suppress the lung metastasis of MDA-MB-231 breast cancer cells.

C-Terminal Region of Caveolin-3 Contains a Stretch of Amino Acid Residues Capable of Diminishing Symptoms of Experimental Autoimmune Encephalomyelitis but Not Rheumatoid Arthritis Modeled in Rats

A short synthetic peptide from the C-terminal part of the caveolin-3 structure was tested for experimental autoimmune encephalomyelitis (EAE) treatment in rats. The structure-function similarity established between the novel synthetic peptide of pCav3 and the well-known immunomodulator immunocortin determined pCav3's ability to reduce EAE symptoms in Dark Agouti (DA) rats injected with pCav3 (500 µg/kg). pCav3 was found to interfere with the proliferation of lymphocytes extracted from the LNs of DA rats primed with homogenate injection, with IC50 = 0.42 μM (2.35 mcg/mL). pCav3 affected EAE in a very similar manner as immunocortin. The high degree of homology between the amino acid sequences of pCav3 and immunocortin corresponded well with the therapeutic activities of both peptides, as demonstrated on EAE. The latter peptide, possessing a homologous structure to pCav3, was also tested on EAE to explore whether there were structural restrictions between these peptides implied by the MHC-involved cell machinery. Consequently, immunocortin was further examined with a different autoimmune disease model, collagen-induced arthritis (CIA), established in Sprague-Dawley rats. CIA was established using an intentionally different genetic platform than EAE. Based on the results, it was concluded that the effectiveness of pCav3 and immunocortin peptides in EAE rat model was almost identical, but differed in the rat model of rheumatoid arthritis; thus, efficacy may be sensitive to the MHC type of animals used to establish the autoimmune disease model.

Leocarpinolide B Attenuates Collagen Type II-Induced Arthritis by Inhibiting DNA Binding Activity of NF-κB

Rheumatoid arthritis (RA) is a chronic autoimmune disease triggered by a cascading inflammatory response. Sigesbeckia Herba (SH) has long been utilized as a traditional remedy to alleviate symptoms associated with rheumatism. Our previous study found that leocarpinolide B (LB), a sesquiterpene lactone isolated from the whole plant of SH, possesses potent a anti-inflammatory effect on macrophages. This study was designed to evaluate the therapeutic effects of LB on RA, and further investigate the underlying mechanisms. In collagen type II-induced arthritic mice, LB was demonstrated to decrease the production of autoimmune antibodies in serum and inflammatory cytokines in the joint muscles and recover the decreased regulatory T lymphocytes in spleen. Moreover, LB significantly suppressed the inflammatory infiltration, formation of pannus and bone erosion in the paw joints. In vitro testing showed that LB inhibited the proliferation, migration, invasion, and secretion of inflammatory cytokines in IL-1β-induced human synovial SW982 cells. Network pharmacology and molecular docking suggested NF-κB p65 could be the potential target of LB on RA treatment, subsequent experimental investigation confirmed that LB directly interacted with NF-κB p65 and reduced the DNA binding activity of NF-κB in synovial cells. In conclusion, LB significantly attenuated the collagen type II-induced arthritis, which was at least involved in the inhibition of DNA binding activity of NF-κB through a direct binding to NF-κB p65. These findings suggest that LB could be a valuable lead compound for developing anti-RA drugs.

Kirenol: A Potential Natural Lead Molecule for a New Drug Design, Development, and Therapy for Inflammation

Kirenol, a potential natural diterpenoid molecule, is mainly found in Sigesbeckia species. Kirenol has received a lot of interest in recent years due to its wide range of pharmacological actions. In particular, it has a significant ability to interact with a wide range of molecular targets associated with inflammation. In this review, we summarise the efficacy and safety of kirenol in reducing inflammation, as well as its potential mechanisms of action and opportunities in future drug development. Based on the preclinical studies reported earlier, kirenol has a good therapeutic potential against inflammation involved in multiple sclerosis, inflammatory bowel disorders, diabetic wounds, arthritis, cardiovascular disease, bone damage, and joint disorders. We also address the physicochemical and drug-like features of kirenol, as well as the structurally modified kirenol-derived molecules. The inhibition of pro-inflammatory cytokines, reduction in the nuclear factor kappa-B (NF-κB), attenuation of antioxidant enzymes, stimulation of heme-oxygenase-1 (HO-1) expression, and nuclear factor erythroid 2-related factor 2 (Nrf2) phosphorylation are among the molecular mechanisms contributing to kirenol's anti-inflammatory actions. Furthermore, this review also highlights the challenges and opportunities to improve the drug delivery of kirenol for treating inflammation. According to the findings of this review, kirenol is an active molecule against inflammation in numerous preclinical models, indicating a path to using it for new drug discovery and development in the treatment of a wide range of inflammations.

Evolving Roles of Natural Terpenoids From Traditional Chinese Medicine in the Treatment of Osteoporosis

Osteoporosis (OP) is a systemic metabolic skeletal disease which can lead to reduction in bone mass and increased risk of bone fracture due to the microstructural degradation. Traditional Chinese medicine (TCM) has been applied in the prevention and treatment of osteoporosis for a long time. Terpenoids, a class of natural products that are rich in TCM, have been widely studied for their therapeutic efficacy on bone resorption, osteogenesis, and concomitant inflammation. Terpenoids can be classified in four categories by structures, monoterpenoids, sesquiterpenoids, diterpenoids, and triterpenoids. In this review, we comprehensively summarize all the currently known TCM-derived terpenoids in the treatment of OP. In addition, we discuss the possible mechanistic-of-actions of all four category terpenoids in anti-OP and assess their therapeutic potential for OP treatment.

Kirenol: A promising bioactive metabolite from siegesbeckia species: A detailed review

ETHNOPHARMACOLOGICAL RELEVANCE

Kirenol (Kr) is an ent-pimarane type diterpenoid that has been reported from Siegesbeckiaorientalis, S. pubescens, and S. glabrescens (family Asteraceae). These plants have been used traditionally for treating various ailments such as hypertension, neurasthenia, rheumatoid arthritis, asthma, snakebites, allergic disorders, paralysis, soreness, cutaneous disorders, rubella, menstrual disorders, numbness of limbs, dizziness, headache, and malaria. Importantly, in recent years, Kr has received great attention due to its diversified pharmacological activities.

AIM OF THE STUDY

The current work aims to give an overview on the reported pharmacological activities of Kr. Furthermore, the findings regarding its methods for extraction, quantitative analysis, purification, pharmacokinetics, pharmaceutical and food preparations, biosynthesis, identification, semisynthetic analogues, and toxicity are highlighted to provide a reference and perspective for its further investigation.

METHODS

Electronic databases including ScienceDirect, Web of Knowledge, SCOPUS, Wiley Online Library, Taylor & Francis, PubMed, Springer, JACS, and Google Scholar were searched up to the beginning of 2021 to identify the reported studies.

RESULTS

A total of 93 articles have been reviewed. The reported data suggested that Kr possessed various bioactivities including cytotoxic, apoptotic, anticancer, anti-inflammatory, cardio-protective, anti-photo-aging, anti-adipogenic, antimicrobial, muscle function improvement, fracture and wound healing, and anti-arthritic. In addition, studies revealed that the antioxidative and anti-inflammatory activities of Kr may mediate many of its therapeutic potentials as confirmed by several in-vitro and in-vivo studies.

CONCLUSION

This review provides an updated summary of the recent studies on Kr, including methods for extraction, quantitative analysis, purification, pharmacokinetics, pharmaceutical and food preparations, biosynthesis, and identification, as well as semisynthetic analogues, pharmacological activities, and toxicity. Thus, this work can provide useful considerations for planning and design future research on Kr.

Herba Siegesbeckiae: A review on its traditional uses, chemical constituents, pharmacological activities and clinical studies

ETHNOPHARMACOLOGICAL RELEVANCE

Herba Siegesbeckiae, mainly includes Sigesbeckia orientalis L, Sigesbeckiae pubescens Makino and Sigesbeckiae glabrescens Makino. Herba Siegesbeckiae, also known as 'Xi-Xian Cao' (Chinese: ), has been regarded as an important traditional Chinese medicine since Tang dynasty. The dried aerial parts of Herba Siegesbeckiae are also being used as a herbal medicine in many countries such as Japan, Korea and Vietnam. In China, Herba Siegesbeckiae has been used for the treatment of rheumatic arthralgia with aching and weakness of loins and knees, as well as numbness of limbs.

AIM OF THIS REVIEW

The aim of this review was to provide critical analysis on the scientific evidence to support the traditional uses of Herba Siegesbeckiae. The information available on its in botanical characteristics, traditional uses, chemical constituents, pharmacological activities, clinical studies, toxicity and quality control was summarized to understand the current research and provided the leas for future study.

MATERIALS AND METHODS

The search terms "Herba Siegesbeckiae", "Sigesbeckia orientalis", "Sigesbeckia pubscens" and "Sigesbeckia glabrescens" were used to obtain the information from electronic databases such as Web of Science, China National Knowledge Infrastructure, PubMed, Google Scholar and SciFinder Scholar and other web search instruments (Springer, Yahoo search). The information provided in this review was based on peer-reviewed papers in English and Chinese. Besides, information was also collected from ancient documents.

RESULT

The studies showed that Herba Siegesbeckiae contains sesquiterpenoids, diterpenoids, flavonoids and organic acids, etc. Due to these constituents, it displayed numerous pharmacological activities, such as anti-inflammatory, antitumor, antiallergic, antioxidant, antithrombotic and antibacterial activities. In addition, it showed effects in protecting myocardial and cerebral ischemia injury.

CONCLUSIONS

According to its traditional uses, chemical constituents, pharmacological activities and clinic studies, Herba Siegesbeckiae is regarded as a promising medical plant with various chemical compounds and numerous pharmacological activities. However, fewer experimental studies were focused on toxicity and quantitative study of 3 species. It suggested that further in-depth study of toxicity and quality control were critical for future evaluation of drug efficacy and safety.

Kirenol Inhibits B[a]P-Induced Oxidative Stress and Apoptosis in Endothelial Cells via Modulation of the Nrf2 Signaling Pathway

Atherosclerosis is a persistent inflammatory disorder specified by the dysfunction of the arteries, the world's leading cause of cardiovascular diseases. We sought to determine the effectiveness of KRL in B[a]P-induced oxidative stress and programmed cell death in endothelial cells. Western blotting, real-time PCR, DCFH2-DA, and TUNEL staining were performed to detect pPI3K, pAKT, Nrf2, HO-1, NQO-1, Bcl2, Bax, and caspase-3 on the HUVECs. Through the pretreatment of KRL, a drastic enhancement was observed in the cell viability of HUVECs, whereas DNA damage and generation of reactive oxygen species induced by B[a]P was suppressed. KRL's potential use as an antioxidant was observed to have a direct correlation with an antioxidant gene's augmented expression and the nuclear translocation activation of Nrf2, even during the event when B[a]P was found to be absent. In addition, this study proved that the signaling cascades of PI3K/AKT mediated Nrf2 translocation. Activation of suppressed nuclear Nrf2 and reduced antioxidant genes across cells interacting with an LY294002 confirmed this phenomenon. In addition, knockdown of Nrf2 by Nrf2-siRNA transfection abolished the protective effects of KRL on HUVECs cells against oxidative damage. Finally, the expression of apoptotic proteins also supported the hypothesis that KRL may inhibit endothelial dysfunction. This study showed that KRL potentially prevents B[a]P-induced redox imbalance in the vascular endothelium by inducing the Nrf2 signaling via the PI3K/AKT pathway.

Hepatoprotective potential of kirenol on ethanol-induced liver toxicity in albino rats and acetaminophen-induced oxidative stress-mediated apoptosis in hepatic HepG2 cells

Liver diseases are a major health issue in both men and women and cause significant mortality worldwide. The hepatoprotective effects of kirenol were evaluated in acetaminophen (APAP)-induced toxicity in HepG2 cells and ethanol (EtOH)- induced hepatotoxicity in rats. The cytotoxicity of kirenol (IC₅₀ , 25 µM/ml) and APAP (20 µg/ml) with sylimarin (IC₅₀ , 15 µg/ml) was observed in HepG2 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Furthermore, reactive oxygen species formation, mitochondrial membrane potential, and oxidative stress markers such as thiobarbituric acid-reactive substance, suproxide dismutase, and catalase were assayed. Rats were administered a different dose (10, 20, and 30 mg/kg/day) for a period of 4 weeks before a single dose of EtOH (40% vol/vol) 3 g/kg/day. EtOH administered rats appeared to have lower body weight gain, severe hepatic and kidney damage as proved by elevated aspartate transaminase, alanine transaminase, alkaline phosphatase, uric acid, increased malondialdehyde (MDA), and inflammatory markers, and reduced glutathione (GSH) levels. Results showed that the kirenol treatment enhanced the GSH and reduced MDA in the liver and renal tissues and restored TNF-α and IL-6. Histoanalysis proved the protective effects of kirenol. In conclusion, it was proved that the kirenol demonstrated a hepato-protective effect in APAP- and EtOH-induced liver toxicity in HepG2 cells and rats, respectively.

Kirenol, darutoside and hesperidin contribute to the anti-inflammatory and analgesic activities of Siegesbeckia pubescens makino by inhibiting COX-2 expression and inflammatory cell infiltration

ETHNOPHARMACOLOGICAL RELEVANCE

The Chinese traditional medicine of Siegesbeckia pubescens Makino (SM), which has the effect of healing rheumatism and promoting joint health, is often used to treat rheumatoid arthritis and ischemic stroke.

AIM OF THE STUDY

To clarify the mechanisms underlying the anti-inflammatory and analgesic influence of active components in the ethanol extract of Siegesbeckia pubescens Makino (ESM).

MATERIALS AND METHODS

The active ingredients in the ESM were identified practicing high-performance liquid chromatography-diode array detection (HPLC-DAD). Four models including xylene-induced ear oedema, complete Freund's adjuvant (CFA)-induced hind paw oedema, acetic acid-induced pain writhing and lipopolysaccharide (LPS)-induced RAW264.7 cell migration, were used to clarify the anti-inflammatory and analgesic mechanisms of the active ingredients in the ESM.

RESULTS

(1) Three active ingredients of kirenol, darutoside and hesperidin were identified in the ESM, with relative proportion of 0.6%, 0.2% and 0.01%, respectively; hesperidin was reported for the first time in the ESM. (2) Both the ESM and its active ingredients could effectively alleviate the degree of swelling of the auricle and toes, increase the threshold of heat pain, decrease the overexpression of inflammatory protein cyclooxygenase-2 (COX-2) in the skin tissue of the tested parts of the toes, and reduce the number of writhes induced by acetic acid in mice. (3) ESM and its active ingredients also dose-dependently inhibited the migration of RAW264.7 cells.

CONCLUSIONS

ESM and its active ingredients can effectively attenuate the expression of inflammatory factors induced by chemical inflammation, prevent the infiltration of inflammatory cells, and exert good anti-inflammatory and antinociceptive activities.

Cardiac Protective Effect of Kirenol against Doxorubicin-Induced Cardiac Hypertrophy in H9c2 Cells through Nrf2 Signaling via PI3K/AKT Pathways

Kirenol (KRL) is a biologically active substance extracted from Herba Siegesbeckiae. This natural type of diterpenoid has been widely adopted for its important anti-inflammatory and anti-rheumatic properties. Despite several studies claiming the benefits of KRL, its cardiac effects have not yet been clarified. Cardiotoxicity remains a key concern associated with the long-term administration of doxorubicin (DOX). The generation of reactive oxygen species (ROS) causes oxidative stress, significantly contributing to DOX-induced cardiac damage. The purpose of the current study is to investigate the cardio-protective effects of KRL against apoptosis in H9c2 cells induced by DOX. The analysis of cellular apoptosis was performed using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining assay and measuring the modulation in the expression levels of proteins involved in apoptosis and Nrf2 signaling, the oxidative stress markers. Furthermore, Western blotting was used to determine cell survival. KRL treatment, with Nrf2 upregulation and activation, accompanied by activation of PI3K/AKT, could prevent the administration of DOX to induce cardiac oxidative stress, remodeling, and other effects. Additionally, the diterpenoid enhanced the activation of Bcl2 and Bcl-xL, while suppressing apoptosis marker proteins. As a result, KRL is considered a potential agent against hypertrophy resulting from cardiac deterioration. The study results show that KRL not only activates the IGF-IR-dependent p-PI3K/p-AKT and Nrf2 signaling pathway, but also suppresses caspase-dependent apoptosis.

Protective Effects of Kirenol against Lipopolysaccharide-Induced Acute Lung Injury through the Modulation of the Proinflammatory NFκB Pathway and the AMPK2-/Nrf2-Mediated HO-1/AOE Pathway

Acute lung injury (ALI) is an acute and life-threatening inflammatory disease of the lung parenchyma that is associated with high mortality worldwide. No therapeutic strategies have been developed for the mitigation of the proinflammatory response that characterizes ALI. Kirenol has anti-inflammatory, antiarthritic, and immunoregulatory effects. In the present study, we investigated the protective effects of kirenol against lipopolysaccharides (LPS)-induced ALI in mice. Kirenol reduced the LPS-induced histopathology changes involving edema and thickening of the interstitial or alveolar walls, infiltration of leukocytes, formation of hyaline membrane. Pretreatment with kirenol reduced leukocytes infiltration in bronchoalveolar lavage fluid (BALF), the alveolar-capillary barrier disruption and lipid peroxidation in lung tissues induced by LPS. Kirenol significantly inhibited the secretion of cytokines, IL-1β, IL6, and TNFα, into the BALF of the mice with LPS-induced ALI through NFκB activation. Moreover, kirenol attenuated the downregulation of the antioxidant enzymes, superoxide dismutase, glutathione peroxidase, and catalase that was induced by LPS. HO-1 expression and the phosphorylation of Nrf2 and AMPK2 were also induced by kirenol. The results indicate that kirenol can be developed as a treatment strategy for ALI, and its effects are induced through the inhibition of the NF-κB proinflammatory pathway and promotion of AMPK2/Nrf2-mediated HO-1 and antioxidant enzymes (AOE) activation.

Kirenol inhibits RANKL-induced osteoclastogenesis and prevents ovariectomized-induced osteoporosis via suppressing the Ca2+-NFATc1 and Cav-1 signaling pathways

BACKGROUND

Osteoporosis is a threat to aged people who have excessive osteoclast activation and bone resorption, subsequently causing fracture and even disability. Inhibiting osteoclast differentiation and absorptive functions has become an efficient approach to treat osteoporosis, but osteoclast-targeting inhibitors available clinically remain rare. Kirenol (Kir), a bioactive diterpenoid derived from an antirheumatic Chinese herbal medicine Herba Siegesbeckiae, can treat collagen-induced arthritis in vivo and promote osteoblast differentiation in vitro, while the effects of Kir on osteoclasts are still unclear.

PURPOSE

We explore the role of Kir on RANKL-induced osteoclastogenesis in vitro and bone loss in vivo.

METHODS

The in vitro effects of Kir on osteoclast differentiation, bone resorption and the underlying mechanisms were evaluated with bone marrow-derived macrophages (BMMs). In vivo experiments were performed using an ovariectomy (OVX)-induced osteoporosis model.

RESULTS

We found that Kir remarkably inhibited osteoclast generation and bone resorption in vitro. Mechanistically, Kir significantly inhibited F-actinring formation and repressed RANKL-induced NF-κB p65 activation and p-p38, p-ERK and c-Fos expression. Moreover, Kir inhibited both the expression and nuclear translocation of NFATc1. Ca2+ oscillation and caveolin-1 (Cav-1) were also reduced by Kir during osteoclastogenesis in vitro. Consistent with these findings, 2-10 mg/kg Kir attenuated OVX-induced osteoporosis in vivo as evidenced by decreased osteoclast numbers and downregulated Cav-1 and NFATc1 expression.

CONCLUSIONS

Kir suppresses osteoclastogenesis and the Cav-1/NFATc1 signaling pathway both in vitro and in vivo and protects against OVX-induced osteoporosis. Our findings reveal Kir as a potential safe oral treatment for osteoporosis.

A New Diterpene and Anti-inflammatory Sesquiterpene Lactones from Sigesbeckia orientalis

Sigesbeckia orientalis, more commonly referred to as Herba Sigesbeckiae or Xi Xian Cao in traditional Chinese medicine and hy thiêm in traditional Vietnamese medicine, is used in China and Vietnam to treat inflammatory diseases such as arthritis, rheumatism, and joint pain. In initial investigations, the dichloromethane extract from the aerial parts of S. orientalis showed distinct inhibitory effects on the release of interleukin-8 in human neutrophils. Therefore, the purpose of the present study was the phytochemical investigation of the bioactive dichloromethane extract and the in vitro analysis of the effects of the isolated compounds on interleukin-8, interleukin-1β, tumor necrosis factor-α, and monocyte chemoattractant protein 1 release, and surface expression of adhesion molecules (CD11a, CD11b, and CD62L) in lipopolysaccharide-stimulated human neutrophils to identify the active principle(s). The separation of the bioactive dichloromethane extract using various chromatographic techniques led to the isolation of nine compounds. Their chemical structures were elucidated from nuclear magnetic resonance and mass spectrometry data. One diterpene, 17(13 → 14)-abeo-ent-3S*,13S*,16-trihydroxystrob-8(15)-ene, was identified as a new natural product. Three germacranolide sesquiterpene lactones inhibited interleukin-8 production with IC₅₀ values between 1.6 and 6.3 µM, respectively, and tumor necrosis factor-α production with IC₅₀ values between 0.9 and 3.3 µM, respectively. Furthermore, they significantly inhibited interleukin-1β and monocyte chemoattractant protein 1 production and diminished the effects of lipopolysaccharide on the surface expression of the adhesion molecules CD11a, CD11b, and CD62L. These findings support the traditional use of S. orientalis in the treatment of inflammatory diseases.

Sigesbeckia glabrescens Makino extract attenuated the collagen-induced arthritis through inhibiting the synovial hyperplasia and inflammation

Background

Sigesbeckia glabrescens Makino (SG) has been traditionally used for rheumatism and joint protection. However, the anti-arthritic effects and underling mechanisms of SG have not been demonstrated. In this study, we investigated the anti-arthritic effects and mechanisms of SG extract (SGE) on collagen-induced arthritic rats and interleukin (IL)-1β-stimulated human synovial SW982 cells.

Methods

Rats were induced to arthritis by collagen for 15 days and then received SGE treatment for 35 days. The body weight and arthritis severity score of the rats were monitored weekly. At the end of the experiment, the radiographic and histological changes of rats’ hind paw were obtained; the serum C-reactive protein was detected by enzyme-linked immunosorbent assay (ELISA); the expression levels of interleukin (IL)- 1β, IL6 and IL-10 in the joint muscles were determined by ELISA and immunohistochemical staining; and the level of regulatory T cells (Tregs) in the spleen was detected using flow cytometry. In addition, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and scratch wound healing assay were used to evaluate the proliferation of SW982 synovial cells. ELISA, western blot and immunofluorescence staining were used to investigate the anti-inflammatory mechanisms of SGE on IL-1β-induced SW982 cells and joint muscles of CIA rats.

Results

SGE attenuated the collagen-induced hind paw swelling, cartilage damage and bone erosion. SGE inhibited the synovial hyperplasia to the articular cavity in the toe joint and ankle. Moreover, SGE decreased the production of C-reactive protein in serum and the expression of IL-6, IL-1β, cyclooxygenase-2 (COX-2) and phosphorylation of NF-κB p65 in the joint muscles. SGE also recovered the decreased Tregs. Results from the in vitro experiments showed that SGE not only inhibited the proliferation and migration of human synovial cell but also inhibited the IL-1β-induced expression of IL-6 and IL-8. Similarly, SGE inhibited the activation of NF-κB and the expression of COX-2.

Conclusions

SGE attenuated the collagen-induced arthritis through inhibiting the synovial hyperplasia and inflammation.

Effect of kirenol on the interaction between the WNT/β-Catenin and RUNX2/TCF/LEF1 pathways in fracture healing in vivo

OBJECTIVE

This study aimed to determine the effects of a natural diterpenoid, kirenol, on fracture healing in vivo in an experimental rat model of femur fracture and investigate its potential mechanism of action via the Wnt/β-catenin pathway.

METHODS

In this study, 64 male Wistar albino rats aged 5-7 weeks and weighing 261-348 g were randomly divided into 8 groups from A to L, with eight rats in each group. Standardized fractures were created in the right femurs of the rats and then fixed with an intramedullary Kirschner wire. Four experimental groups were administered 2 mg/kg/day kirenol (Groups C and G) and 4 mg/kg/day (Groups D and H) kirenol by oral gavage.Thereafter, the animals were sacrificed at two time points as follows: on the 10th day (Groups B, C and D) and on the 21st day (Groups F, G and H) after the surgery; fracture healing in each group was assessed radiologically and histopathologically. The Radiographic Union scale of tibia fracture scoring system was used in the radiological examination; callus volume and density were measured using computed tomography. In the histopathologic examination, the scoring system described by Huo et al. was used. Additionally, the mechanism of action was evaluated based on the analyses of protein expression of Wnt3a, LRP5, TCF-LEF1, β-catenin, and Runx-2 proteins using western blot analysis.

RESULTS

Among the animals sacrificed on the 10th day after the surgery, the highest histopathological and radiological scores were observed in Group D (p<0.05). Furthermore, the callus density (p<0.05) was highest in Group D. Among the animals sacrificed on the 21st day, the highest histopathological and radiological scores were found in Group H, although the differences among the groups were not significant (p>0.05). The callus volume and density were the highest in Groups G and H, respectively, although the differences among groups were not significant.

CONCLUSION

Kirenol may improve fracture healing in a dose-dependent manner with the early activation of the Wnt/β-catenin pathway and the activation of the Runx-2 pathway.

[Kirenol relieves dextran sulfate sodium-induced ulcerative colitis in mice by inhibiting inflammatory cytokines and inducing CD4+ T lymphocyte apoptosis]

OBJECTIVE

To investigate whether kirenol, the major pharmacologically active compound of the Chinese medicinal herb Herba Siegesbeckiae, can protect mice from dextran sulfate sodium (DSS)-induced ulcerative colitis (UC).

METHODS

C57BL/6 mice with or without kirenol pretreatment were treated with DSS in drinking water for 7 days to induce UC. The symptoms of UC including weight loss, diarrhea and bloody stool were observed daily and graded using the disease activity index (DAI). Colon injury of the mice was assessed by measuring the length of the colon and HE staining of the colon tissue. The levels of inflammatory cytokines produced by the mesenteric lymph nodes (MLNs) lymphocytes were measured using enzyme-linked immunosorbent assay; the apoptosis of the lymphocytes and CD4⁺ T cells was analyzed using flow cytometry.

RESULTS

The mice receiving pretreatment with kirenol showed obviously ameliorated symptoms of UC and milder pathological changes in the colon as compared with the control mice. Kirenol treatment significantly down-regulated the secretion of IFN-γ, IL-17A, IL-6 and TNF-α by the MLNs lymphocytes and increased the apoptosis of lymphocytes, especially CD4⁺ T cells in the DSS-treated mice.

CONCLUSIONS

Kirenol can protect against T cell-mediated colon injury in DSS-treated mice possibly by suppressing the secretion of inflammatory mediators and inducing apoptosis of the inflammatory lymphocytes.

Synthesis and preliminary anti-inflammatory activity exploration of novel derivatives of kirenol

It has been shown in many studies that kirenol is a diterpene with significant biological activity.

Leocarpinolide B attenuates LPS-induced inflammation on RAW264.7 macrophages by mediating NF-κB and Nrf2 pathways

Macrophages-mediated inflammation is involved in the regulation of rheumatoid arthritis (RA). Sigesbeckiae Herba (SH) has been traditionally used for rheumatism. However, the bioactive ingredients of SH are still unclear. Recently, we isolated a compound (Leocarpinolide B, LB) from SH and identified its potent anti-inflammatory and antioxidant effects on RAW264.7 macrophages for the first time. LB effectively inhibited excessive production of nitric oxide (NO), prostaglandin E2 (PGE₂), cytokines (IL-6, TNF-α and MCP-1), and the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthases (iNOS) in lipopolysaccharide (LPS)-induced RAW264.7 cells. LB blocked the degradation of inhibitor of kappa B (IκBα) and translocation of nuclear factor kappa B (NF-κB) p65. Additionally, LB reduced the intracellular reactive oxygen species, and increased the expression of heme oxygenase-1 (HO-1) and the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) in the presence or absence of LPS. The results suggested that LB might be one of the bioactive components of SH, and be potential for the treatment of RA and valuable to be further investigated.

Anti-Inflammatory Properties of Plant Derived Natural Products - A Systematic Review

Traditionally, natural medicines have been administered as plant extracts, which are composed of a mixture of molecules. The individual molecular species in this mixture may or may not contribute to the overall medicinal effects and some may even oppose the beneficial activity of others. To better control therapeutic effects, studies that characterized specific molecules and describe their individual activity that have been performed over the past decades. These studies appear to underline that natural products are particularly effective as antioxidants and anti-inflammatory agents. In this systematic review we aimed to identify potent anti-inflammatory natural products and relate their efficacy to their chemical structure and physicochemical properties. To identify these compounds, we performed a comprehensive literature search to find those studies, in which a dose-response description and a positive control reference compound was used to benchmark the observed activity. Of the analyzed papers, 7% of initially selected studies met these requirements and were subjected to further analysis. This analysis revealed that most selected natural products indeed appeared to possess anti-inflammatory activities, in particular anti-oxidative properties. In addition, 14% of the natural products outperformed the remaining natural products in all tested assays and are attractive candidates as new anti-inflammatory agents.

Attenuation of diabetic cardiomyopathy by relying on kirenol to suppress inflammation in a diabetic rat model

Diabetic cardiomyopathy is characterized by diabetes‐induced myocardial abnormalities, accompanied by inflammatory response and alterations in inflammation‐related signalling pathways. Kirenol, isolated from Herba Siegesbeckiae, has potent anti‐inflammatory properties. In this study, we aimed to investigate the cardioprotective effect of kirenol against DCM and underlying the potential mechanisms in a type 2 diabetes mellitus model. Kirenol treatment significantly decreased high glucose‐induced cardiofibroblasts proliferation and increased the cardiomyocytes viability, prevented the loss of mitochondrial membrane potential and further attenuated cardiomyocytes apoptosis, accompanied by a reduction in apoptosis‐related protein expression. Kirenol gavage could affect the expression of pro‐inflammatory cytokines in a dose‐dependent manner but not lower lipid profiles, and only decrease fasting plasma glucose, fasting plasma insulin and mean HbA1c levels in high‐dose kirenol‐treated group at some time‐points. Left ventricular dysfunction, hypertrophy, fibrosis and cell apoptosis, as structural and functional abnormalities, were ameliorated by kirenol administration. Moreover, in diabetic hearts, oral kirenol significantly attenuated activation of mitogen‐activated protein kinase subfamily and nuclear translocation of NF‐κB and Smad2/3 and decreased phosphorylation of IκBα and both fibrosis‐related and apoptosis‐related proteins. In an Electrophoretic mobility shift assay, the binding activities of NF‐κB, Smad3/4, SP1 and AP‐1 in the nucleus of diabetic myocardium were significantly down‐regulated by kirenol treatment. Additionally, high dose significantly enhanced myocardial Akt phosphorylation without intraperitoneal injection of insulin. Kirenol may have potent cardioprotective effects on treating for the established diabetic cardiomyopathy, which involves the inhibition of inflammation and fibrosis‐related signalling pathways and is independent of lowering hyperglycaemia, hyperinsulinemia and lipid profiles.

Anti-inflammatory activities of Sigesbeckia glabrescens Makino: combined in vitro and in silico investigations

BACKGROUND

Sigesbeckia glabrescens Makino (SG) is one of the important plant origins of Sigesbeckiae herba and has been widely used for the treatment of chronic inflammatory diseases in China. However, the underlying anti-inflammatory mechanism of SG is rarely investigated and reported. There are more than 40 kinds of chemical constituents in SG, but the action of the bioactive compounds of SG is still unclear. Therefore, we aimed to systemically investigate the mechanisms behind the anti-inflammatory properties of SG by combining in vitro and in silico investigations.

METHODS

Cytotoxicity was measured using the 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Nitric oxide (NO) release was detected using the Griess assay. The secretion of pro-inflammatory cytokines and the expression of relevant proteins were assessed using ELISA kits and Western blots, respectively. Molecular docking was performed and scored using AutoDock via a comparison with the molecular docking of N-acetyl-d-glucosamine (NAG).

RESULTS

In lipopolysaccharides (LPS)-stimulated macrophages, SG significantly inhibited NO, MCP-1, and IL-6 secretion; iNOS expression; and NF-κB activation but did not significantly affect MAPK signalling (p38, ERK, and JNK). Moreover, the results from the molecular docking prediction suggested that over 10 compounds in SG could likely target TLR4, p105, and p65.

CONCLUSIONS

These findings suggest that the anti-inflammatory effects of SG are highly related to the inactivation of NF-κB. Moreover, this study provides a novel approach to investigate the effects of herbal medicine using combined in vitro and in silico investigations.

Herbal compounds for rheumatoid arthritis: Literatures review and cheminformatics prediction

Rheumatoid arthritis (RA) is a systemic disease characterized by autoimmunity, joint inflammation, and cartilage destruction, which affects 0.5-1% of the population. Many compounds from herbal medicines show the potentials to treat RA. On this basis, the compounds with good pharmacokinetic behaviors and drug-likeness properties will be further studied and developed. Therefore, the herbal compounds with anti-RA activities were reviewed in this paper, and the cheminformatics tools were used to predict their drug-likeness properties and pharmacokinetic parameters. A total of 90 herbal compounds were analyzed, which were reported to be effective on RA models through anti-inflammation, chondroprotection, immunoregulation, antiangiogenesis, and antioxidation. Most of the herbal compounds have good drug-likeness properties. Most of the compounds can be an alternative and valuable source for anti-RA drug discovery.

Isolation and characterization of ent-pimarane diterpenoids from Sigesbeckia pubescens

Five new ent-pimarane diterpenoids ent-16-nor-2-oxopimar-8(14)-ene-15,19-dial (1), ent-16-nor-2α,19-dihydroxypimar-8-en-15-al (2), 3-O-acetyldarutigenol (3), 19-O-acetylkirenol (4), ent-16-nor-3β,15-dihydroxypimar-8(14)-ene (5) were isolated and characterized from the ethanol extract of Sigesbeckia pubescens. Their structures were elucidated on the basis of spectroscopic analysis. The absolute configuration of C-15 in compounds 3 and 4 was assigned using Snatzke's method. All these compounds were assessed for their anti-inflammatory potential by measuring the inhibitory effects on NO production in LPS-induced RAW 264.7 macrophage cells and compound 4 showed significantly inhibitory activity with IC₅₀ value of 5.9 μM.

Recipient natural killer cells alter the course of rejection of allogeneic heart grafts in rats

Rejection of solid organ grafts is regarded to be dependent on T cell responses. Nonetheless, numerous studies have focused on the contribution of NK cells in this process, resulting in contradictory theories. While some conclude that there is no participation of NK cells, others found an inflammatory or regulative role of NK cells. However, the experimental settings are rarely comparable with regard to challenged species, strain combinations or the nature of the graft. Thus, clear definition of NK cell contribution might be impeded by these circumstances. In this study we performed heterotopic heart transplantation (HTx) in rats, choosing one donor-recipient-combination leading to a fast and a second leading to a prolonged course of graft rejection. We intervened in the rejection process, by depletion of recipient NK cells on the one hand and by injection of activated NK cells syngeneic to the recipients on the other. The fast course of rejection could not be influenced by any of the NK cell manipulative treatments. However, the more prolonged course of rejection was highly susceptible to depletion of NK cells, resulting in significant acceleration of rejection, while injection of NK cells induced acceptance of the grafts. We suggest that, depending on the specific setting, NK cells can attenuate the first trigger of immune response, which allows establishing the regulatory activity leading to tolerance of the graft.

Daurinol Attenuates Autoimmune Arthritis via Stabilization of Nrp1-PTEN-Foxp3 Signaling in Regulatory T Cells

Optimizing Treg function and improving Treg stability are attractive treatment strategies for treating autoimmune rheumatoid arthritis (RA). However, the limited number of circulating Tregs and questions about the functional stability of in vitro-expanded Tregs are potential limitations of Treg-based cell therapy. The aim of this study was to analyze the regulatory effect of daurinol, a catalytic inhibitor of topoisomerase IIα, on Th cell differentiation and to evaluate their therapeutic potential in a preclinical experimental model of RA. We investigated the effect of daurinol on T cell differentiation by flow cytometry. Foxp3 stability and methylation were analyzed by suppression assays and bisulfite pyrosequencing. Daurinol was treated in the collagen-induced arthritis (CIA) model, and the effects in vivo were determined. We found that daurinol can promote Treg differentiation and reciprocally inhibit Th17 differentiation. This Treg-inducing property of daurinol was associated with decreased activity of Akt-mTOR and reciprocally increased activity of neuropilin-1 (Nrp1)-PTEN. Daurinol treatment inhibited aerobic glycolysis in Th17 conditions, indicating the metabolic changes by daurinol. We found that the daurinol increase the Treg stability was achieved by Foxp3 hypomethylation. In vivo daurinol treatment in CIA mice reduced the clinical arthritis severity and histological inflammation. The Treg population frequency increased and the Th17 cells decreased in the spleens of arthritis mice treated with daurinol. These results showed the anti-arthritic and immunoregulating properties of daurinol is achieved by increased differentiation and stabilization of Tregs. Our study provides first evidence for daurinol as a treatment for RA.

Kirenol Inhibits the Function and Inflammation of Fibroblast-like Synoviocytes in Rheumatoid Arthritis in vitro and in vivo

Kirenol is a diterpenoid extracted from the Chinese herbal medicine Siegesbeckiae. Siegesbeckiae has been used to treat Rheumatoid arthritis (RA) in China for several centuries. RA is characterized by the proliferation of synoviocytes in inflamed synovia, as well as by their expression of inflammatory cytokines. In the present study, we found that Kirenol inhibited the migration, invasion, and proinflammatory of IL-6 secretion of RA-associated synovial fibroblasts (FLS) at a concentration of 100–200 μg/ml in vitro. Proinflammatory cytokines production and synovium hyperplasia and cartilage erosion were also inhibited in a collagen-induced arthritis (CIA) mouse model upon Kirenol treatment. Together, our results thus confirm that Kirenol has potent therapeutic efficacy in RA owing to its ability to suppress negative FLS activities.

Terpenes as possible drugs for the mitigation of arthritic symptoms - A systematic review

BACKGROUND

Arthritis is a syndrome associated with exacerbated inflammation, joint destruction and chronic pain and disability. Chronic treatment of arthritis is associated with several side effects and high abandonment. Therefore, there has been an ongoing search for alternative treatments to overcome these problems.

PURPOSE

Natural products, which are already widely used for their biological, cosmetic and pharmacotechnic properties, are a possible source for new drugs. Terpenes, a large class of organic compounds produced mainly by plants and trees, are a promising natural product and have already been shown to be effective in treating chronic pain, particularly of an inflammatory origin.

STUDY DESIGN AND METHODS

This review identifies the main terpenes with anti-arthritic activity reported in the last 10 years. A survey was conducted between December 2017 and June 2018 in the PUBMED, SCOPUS and Science Direct databases using combinations of the descriptors terpenes, arthritis and inflammation.

RESULTS

The results showed that terpenes have promising biological effects in relation to the treatment of arthritis, with the 24 terpenes identified in our survey being effective in the modulation of inflammatory mediators important to the physiopathology of arthritis, such as IL-6, IL-17, TNF-α, NFκB, and COX-2, among others. It is important to note that most of the studies used animal models, which limits, at least in part, the direct translation to humans of the experimental evidence produced by the studies.

CONCLUSION

Together, our finds suggest that terpenes can modulate the immuno-regulatory and destructive tissue events that underlie the clinical presentation and the progression of arthritis and are worthy of further clinical investigation.

Semisynthesis of ent-norstrobane diterpenoids as potential inhibitor for factor Xa

A semisynthesis of two ent-strobane diterpenoids strobols C (7) and D (14) was accomplished via a Wagnar-Meerwein rearrangement. Compounds 7, 14, and the intermediate products were evaluated for their inhibition on factor Xa (FXa). Among all the compounds screened for FXa inhibitory activity, three compounds 6, 7, and 9 showed significant inhibitory activities with IC₅₀ values of 1067 ± 164, 81 ± 11, 1023 ± 89 nM, respectively. The inhibitory activity on FXa described in this study highlight the importance of structural modification based on natural products in the development of FXa inhibitors.

Siegesbeckia Orientalis L. Extract Attenuates Postoperative Cognitive Dysfunction, Systemic Inflammation, and Neuroinflammation

A proportion of patients experience acute or even prolonged cognitive impairment after surgery, a condition known as postoperative cognitive dysfunction (POCD). It is characterized by impairment in different cognitive domains and neuroinflammation has been implicated as one of the inciting factors as strategies targeting inflammation tend to improve cognitive performance. Siegesbeckia Orientails L. (S. Orientails) is a common Chinese medicinal herb used for managing chronic inflammatory diseases. We investigated if pretreatment with S. Orientails before surgery confers any neuroprotective effects in postoperative animals in terms of reducing inflammation and mitigating cognitive impairment. Three-month-old male C57BL/6N mice were fed different doses of S. Orientails extract for 14 days before they underwent a laparotomy. After cognitive testing they were sacrificed on postoperative day (POD) 3. Our results showed that animals with extract pretreatment demonstrated memory improvement in a dose-dependent manner compared with control. Further, evidence for the attenuation of systemic and neuroinflammation was found in the pretreated animals, along with the inhibition of inflammatory pathways and significantly reduced tau phosphorylation in the hippocampus. Taken together, these results demonstrated a neuroprotective effect of S. Orientails in postoperative animals, indicating a therapeutic potential of S. Orientails in minimizing POCD and the possibility of utilizing this traditional Chinese medicine perioperatively.

Simultaneous Determination of Kirenol, Rosmarinic Acid and Caffeic Acid in Rat Plasma and Pharmacokinetic Study After Oral Administration of the Extract of Manxingshizhen Preparation by UPLC-MS/MS

Introduction:

A rapid, sensitive and convenient ultra-performance liquid chromatography with tandem mass spectrometric detection (UPLC-MS/MS) method has been validated and applied to the simultaneous determination of kirenol, rosmarinic acid and caffeic acid after oral administration of the extract of Manxingshizhen preparation in rat plasma.

Materials and Methods:

Puerarin was selected as the internal standard (IS). The plasma sample preparation was pretreated by liquid-liquid extraction of the mixture with ethyl acetate. All analytes were simultaneously detected in multiple reaction monitoring (MRM) mode via both the positive electrospray ionization (ESI+) and negative electrospray ionization (ESI). In the experiment, all calibration curves revealed good linearity (r > 0.999). The LLOQ were between 0.80-2.00 ng/mL, respectively.

Besides, the intra-day and inter-day precision ranged from 6.4 to 13.8%, respectively. Moreover, the accuracy was within - 11.4% and 12.8% for all the QC levels of all analytes. The extraction recoveries of the analytes and IS in plasma at three concentration levels ranged from 88.5 to 103.2%, moreover, the matrix effects of all the analytes and the IS were found to be satisfied with the acceptable range of 89.8%-101.7%. Meanwhile, the RSD values of stability met the requirement of not more than 15%. Furthermore, the pharmacokinetic parameters of three compounds were analyzed using concentrationtime profiles.

Conclusion and Results:

Plasma concentrations of the three compounds were determined up to 24 h after oral administration, and their pharmacokinetic parameters were in agreement with previous studies. The validated method was successfully applied in a pharmacokinetic study in rat plasma after oral administration of Manxingshizhen preparation.

Therapeutic effects of polysaccharides from Anoectochilus roxburghii on type II collagen-induced arthritis in rats

Anoectochilus roxburghii, a famous Chinese herbal medicine, has been commonly used for the treatment of liver disease, diabetes, and rheumatoid arthritis. Our study aimed to investigate the anti-rheumatoid arthritis effects of A. roxburghii polysaccharides (ARP), using the rat's model of type II collagen-induced arthritis (CIA). ARP was prepared by alcohol sedimentation and structurally characterized based on combined chemical, chromatographic and spectroscopic methods. High Performance Size Exclusion Chromatography-Multiangle Laser Light Scattering-Refrative Index (HPSEC-MALLS-RI) analysis revealed that ARP includes two peaks, and the weight-average molecular weight (Mw) of the principal one was estimated as 5.90 kDa with a relative content of 98.2%. Pharmacological results exhibited that ARP significantly decreased the arthritis index and ameliorated the inflammatory cell infiltration and the synovial tissue destruction in CIA rats. Additionally, ARP possessed significant NO production inhibitory effects and antioxidant activity. Further anti-inflammatory mechanism investigations indicated that ARP significantly inhibited the activation of nuclear factor κB (NF-κB) pathway by suppressing the phosphorylation of IκB and p65, which subsequently down-regulated the mRNA expressions of IL-1β and IL-6 in LPS-stimulated RAW 264.7 cells. These findings suggested that ARP has great potential in the development of functional foods and dietary supplements for the treatment of rheumatoid arthritis.

Siegesbeckia pubescens Makino inhibits Pam3CSK4-induced inflammation in RAW 264.7 macrophages through suppressing TLR1/TLR2-mediated NF-κB activation

Background

Siegesbeckia pubescens Makino (SP) is one of the important plant origins for the anti-inflammatory Chinese herbal medicine of Siegesbeckiae Herba. The current investigations indicated that the anti-inflammatory effects of SP were associated with the toll-like receptors (TLRs)-mediated nuclear factor-κB (NF-κB) and the mitogen-activated protein kinase (MAPK) signaling pathways.

Methods

Raw 264.7 macrophages were pretreated with the 50% ethanol extract of SP (SPE, 50–200 µg/mL) and then co-treated with Pam₃CSK₄ (200 ng/mL) for another 12 h. The inhibitory effect of SPE on Pam₃CSK₄-stimulated NO release and post-inflammatory cytokines secretions were determined using Griess reagent and Elisa kits, respectively. The influence of SPE on NF-κB and MAPKs signaling relevant proteins was measured by Western blotting analysis, while the intracellular nitric oxide (NO) generation and NF-κB/p65 nuclear translocation were determined using Leica TCS SP8 laser scanning confocal microscope. Moreover, the effect of SPE on luciferase reporter gene in NF-κB-luc DNA transfected raw 264.7 cells was determined using the Dual-Glo luciferase assay system kit.

Results

SPE dose-dependently (50–200 µg/mL) attenuated Pam₃CSK₄-induced NO release, post-inflammatory cytokines (IL-6, TNF-α and MCP-1) secretions and intracellular NO generation in raw 264.7 cells. Biologically, SPE suppressed Pam₃CSK₄-induced expressions of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), phosphorylation of NF-κB/p65 and IκBα, but did not significantly show effect on the proteins involved in MAPKs signaling (p38, ERK and JNK). The results were further confirmed by NF-κB-luc reporter gene assay and p65 nuclear translocation assay.

Conclusions

In conclusion, SPE ameliorated Pam₃CSK₄-induced inflammation in raw 264.7 cells through suppressing TLR 1/2-mediated NF-κB activation.

Electronic supplementary material

The online version of this article (10.1186/s13020-018-0193-x) contains supplementary material, which is available to authorized users.

In-vivo quantitative assessment of the therapeutic response in a mouse model of collagen-induced arthritis using 18 F-fluorodeoxyglucose positron emission tomography

Mouse collagen-induced arthritis (CIA) is the most commonly used animal model to investigate underlying pathogenesis of autoimmune arthritis and to demonstrate the therapeutic efficacy of novel drugs in autoimmune arthritis. The conventional read-outs of CIA are clinical score and histopathology, which have several limitations, including (i) subjected to observer bias; and (ii) longitudinal therapeutic efficacy of a new drug cannot be determined. Thus, a robust, non-invasive, in-vivo drug screening tool is currently an unmet need. Here we have assessed the utility of 18 F-fluorodeoxyglucose positron emission tomography (18 F-FDG) as an in-vivo screening tool for anti-inflammatory drugs using the mouse CIA model. The radiotracer 18 F-FDG and a PET scanner were employed to monitor CIA disease activity before and after murine anti-tumour necrosis factor (TNF)-α antibody (CNTO5048) therapy in the mouse CIA model. Radiotracer concentration was derived from PET images for individual limb joints and on a per-limb basis, and Spearman's correlation coefficient (ρ) was determined with clinical score and histology of the affected limbs. CNTO5048 improved arthritis efficiently, as evidenced by clinical score and histopathology. PET showed an increased uptake of 18 F-FDG with the progression of the disease and a significant decrease in the post-treatment group. 18 F-FDG uptake patterns showed a strong correlation with clinical score (ρ = 0·71, P < 0·05) and histopathology (ρ = 0·76, P < 0·05). This study demonstrates the potential of 18 F-FDG PET as a tool for in-vivo drug screening for inflammatory arthritis and to monitor the therapeutic effects in a longitudinal setting.

ent-Strobane and ent-Pimarane Diterpenoids from Siegesbeckia pubescens

Two strobane diterpenoids, strobols A (1) and B (2), 15 new pimarane diterpenoids (3-6 and 8-18), and the known compounds kirenol (19), darutigenol (20), and ent-2β,15,16,19-tetrahydroxypimar-8(14)-ene (7) were isolated from the aerial parts of Siegesbeckia pubescens Makino. The structures of the new compounds were established based on the interpretation of HRESIMS and NMR analysis. The configurations of 1, 6, and 17 were confirmed by X-ray crystallographic data. Compounds 3, 5, and 11 inhibited the migration of MB-MDA-231 breast cancer cells induced by the chemokine epithelial growth factor, with IC₅₀ values of 4.26, 3.45, and 9.70 μM, respectively.

Xitong Wan attenuates inflammation development through inhibiting the activation of nuclear factor-κB in rats with adjuvant-induced arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Xitong Wan (XTW), a traditional Chinese herbs formula, has been used to treat "Bi Zheng" in the clinical practice of traditional Chinese medicine (TCM) for hundreds of years. However, no scientific validation is available on the anti-rheumatic effect of XTW.

AIM OF STUDY

This study was carried out to investigate the effects of XTW on joints swelling, joints destruction, production of inflammatory mediators and nuclear factor-κB (NF-κB) activation in rats with adjuvant-induced arthritis (AIA).

MATERIALS AND METHODS

AIA was induced by intradermal injection of Complete Freund's adjuvant in the footpad of Wistar rats. Paw volume was measured every 7 days during XTW treatment. Histological score was calculated by hematoxylin and eosin staining. Osteoclast number in articular tissues was counted by tartrate-resistant acid phosphatase staining. Levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in serum were detected by enzyme-linked immunosorbent assay. Levels of NF-κBp65 and inhibitor of NF-κB (IκB)α in synovium were analyzed by Western blot assay.

RESULTS

Compared with AIA group rats, XTW significantly decreased the paw volume of AIA rats. Meanwhile, XTW significantly reduced the histological score and osteoclast number in articular tissues of AIA rats. In addition, XTW markedly abated the levels of TNF-α, IL-1β and IL-6 in serum, as well as enhanced the level of IκBα in synovium of AIA rats. However, XTW did not show significant effect on the level of p65 in synovium of AIA rats.

CONCLUSIONS

These results suggest that XTW attenuates the inflammation development through inhibiting the NF-κB-mediated proinflammatory cytokines production in AIA rats. Our study provides the scientific evidence of XTW on treatment of rheumatoid arthritis in the clinical practice of TCM.

Therapeutic effects of Caragana pruinosa Kom. roots extract on type II collagen-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Caragana pruinosa Kom. is a deciduous shrub belonging to the genus of Caragana (Leguminosae), and Caragana plants exhibit a wide range of interesting pharmacological properties including anti-inflammatory, analgesic, and anti-arthritis activity, etc.

AIM OF THE STUDY

This study was aimed to investigate the anti-arthritic effect of 80% EtOH extract from the roots of C. pruinosa (ERCP) on arthritis and explore the potential pharmacological mechanism.

MATERIALS AND METHODS

After collagen induced arthritis (CIA) were established in rats, the animals were orally administered with ERCP (130, 260 and 520mg/kg) for 30 days. During the treatment, the rats' body weights, arthritis indices and paw volumes were measured every 5 days. Subsequently, rats' blood samples were collected to determine TNF-α, IL-1β, IL-6, IL-10, and C-reactive protein (CRP) contents in serum. Then, rats were sacrificed and the hind paws and knee joints were collected for histopathological examination.

RESULTS

Our results indicated that ERCP significantly suppressed the inflammatory reactions and destructions in joints and synovial tissues. ERCP inhibited the paw swelling and arthritis index in CIA rats. Additionally, it decreased the levels of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) and CRP, whereas increased that of IL-10.

CONCLUSION

Our results suggested ERCP has significant anti-arthritic effect on CIA rats, and the pharmacological mechanisms are related to the down-regulation of TNF-α, IL-1β, IL-6 and CRP and the up-regulation of IL-10.

Matrine Exerts a Strong Anti-Arthritic Effect on Type II Collagen-Induced Arthritis in Rats by Inhibiting Inflammatory Responses

To investigate anti-arthritic effects of matrine isolated from the roots of S. flavescens on type II collagen-induced arthritis (CIA) in rats and to explore its related potential mechanisms, CIA rats were established and administered with matrine (20, 40 or 80 mg/kg/days, for 30 days). Subsequently, blood was collected to determine serum levels of TNF-α, IL-1β, IL-6, IL-8, IL-17A, IL-10, MMP-2, MMP-3 and MMP-9, and hind paws and knee joints were collected for histopathological examination. Furthermore, indices of the thymus and spleen were determined, and synovial tissues were collected to determine the protein expressions of p-IκB, IκB, Cox-2 and iNOS. Our results indicated that matrine significantly suppressed inflammatory reactions and synovial tissue destruction. Matrine inhibited paw swelling, arthritis indices and weight loss in CIA rats. Additionally, matrine decreased the levels of TNF-α, IL-1β, IL-6, IL-8, IL-17A, MMP-2, MMP-3 and MMP-9. Matrine also down-regulated expressions of p-IκB, Cox-2, and iNOS but up-regulated IκB in synovial tissues in CIA rats. The results suggested matrine possesses an anti-arthritic effect in CIA rats via inhibiting the release of pro-inflammatory cytokines and proteins that promote the NF-κB pathway.

The treatment of rheumatoid arthritis using Chinese medicinal plants: From pharmacology to potential molecular mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis (RA) is a common worldwide public health problem. Traditional Chinese Medicine (TCM) achieved some results to some extent in the treatment of rheumatoid arthritis (RA). Especially in China, TCM formulas are used in the clinic because of their advantages. Some of these TCM formulas have been used for thousands of years in ancient China, they pays much attention to strengthening healthy qi, cleaning heat, and wet, activating blood, etc. So TCM in anti-RA drug is considered as a simple and effective method. In addition, TCM are also traditionally used as extracts and many Chinese herbs which are considered to be effective for RA. With the advancement of technologies and research methods, researchers have devoted themselves to exploring new therapeutic materials from troves of TCM. The components of TCM are identified and purified, which include alkaloids, coumarins, flavonoids, saponins and so on. However, little or no review works are found in the research literature on the anti-RA drugs from TCM. The present review aims to provide systematically reorganized information on the ethnopharmacology, phytochemistry and pharmacology of TCM used traditionally against RA. The information recorded in this review will provide new directions for researchers in the future.

MATERIALS AND METHODS

Relevant scientific literatures were collected from Chinese traditional books and Chinese Pharmacopoeia. Several important pharmacology data, clinical observations, animal experiments on effects of anti-RA drugs from TCM and their mechanisms were extracted from a library and electric search (Pubmed, PubChem Compound, Science Direct, Spring Link, Elsevier, Web of Science, CNKI, Wan Fang, Bai du, The Plant List, etc.). We collected information published between 2002 and 2015 on Chinese medicine in the treatment of RA. Information was also acquired from local classic herbal literature, conference papers, government reports, and PhD and MSc dissertations.

RESULTS

This review mainly introduces the current research on anti-RA TCM formulas, extracts and compounds from TCM, pharmacological data and potential mechanisms (inhibit osteoclast proliferation, suppress fibroblast-like synoviocytes (FLSs) growth, decrease the expression of inflammatory cytokines, blocking signal pathways, etc.).

CONCLUSIONS

TCM, as a multi-component and multi-target approach, which is a perfect match with the holistic concept of systems biology, is applicable in the treatment of RA. The synergistic connections of Chinese herbs and mechanisms of related active compounds on RA increase the trust for TCM. TCM as alternative remedies for RA not only has an important position in the world market, but also has an irreplaceable role in the treatment of RA in future.

Crude triterpenoid saponins from Anemone flaccida (Di Wu) exert anti-arthritic effects on type II collagen-induced arthritis in rats

Background

Anemone flaccida Fr . Schmidt (Ranunculaceae) (Di Wu in Chinese) is used to treat punch injury and rheumatoid arthritis (RA). However, the active compounds and underlying mechanism of action mediating the anti-arthritic effects of A. flaccida remain unclear. This study aims to evaluate the underlying action mechanism of A. flaccida crude triterpenoid saponins (AFS) on RA using a type II collagen (CII)-induced arthritis (CIA) rat model, and to assess the anti-inflammatory effects of the main active compounds of AFS, namely flaccidoside II, anhuienoside E, glycoside St-I4a, hemsgiganoside B, hederasaponin B, and 3-O-α-l-rhamnopyranosyl (1 → 2)-β-d-glucopyranosyl oleanolic acid 28-O-β-d-glucopyranosyl (1 → 6)-β-d-glucopyranosyl ester.

Methods

Male Wistar rats (n = 50) were randomly separated into five groups (n = 10) and immunized by CII injection. AFS (200 or 400 mg/kg) and dexamethasone were orally administered for 30 days after establishing the model. The arthritis severity was assessed by paw volume using a plethysmometer. After 30 days of treatment, the right hind paws of the rats were obtained. Paw histology was analyzed by hematoxylin and eosin staining, and radiologic imaging was performed by micro-computed tomography. MTT assays were used to evaluate the cytotoxicity of AFS and its main compounds in RAW264.7 cells. Enzyme-linked immunosorbent assay kits were used to measure interleukin (IL)-6 and tumor necrosis factor (TNF)-α in serum and supernatants from AFS- and main AFS compound-treated RAW264.7 cells stimulated by lipopolysaccharide (LPS).

Results

Anemone flaccida crude triterpenoid saponins inhibited redness and swelling of the right hind paw in the CIA model. Radiological and histological examinations indicated that inflammatory responses were reduced by AFS treatment. Moreover, comparing with untreated rats, serum TNF-α (P = 0.0035 and P < 0.001) and IL-6 (P = 0.0058 and P = 0.0087) were lower in AFS-treated CIA rats at the dose of 200 and 400 mg/kg/day. AFS and its main compounds, including hederasaponin B, flaccidoside II, and hemsgiganoside B, significantly inhibited TNF-α (P = 0.0022, P = 0.013, P = 0.0015, and P = 0.016) and IL-6 (P = 0.0175, P < 0.001, P < 0.001, and P < 0.001) production in LPS-treated RAW264.7 cells, respectively.

Conclusions

Anemone flaccida crude triterpenoid saponins and its main bioactive components, including hederasaponin B, flaccidoside II, and hemsgiganoside B, decreased pro-inflammatory cytokine levels in a CIA rat model and LPS-induced RAW264.7 cells.