Elsevier

Journal of Ethnopharmacology

Volume 237, 12 June 2019, Pages 20-27
Journal of Ethnopharmacology

Glycine tabacina ethanol extract ameliorates collagen-induced arthritis in rats via inhibiting pro-inflammatory cytokines and oxidation

https://doi.org/10.1016/j.jep.2019.03.035Get rights and content

Abstract

Ethnopharmacological relevance

The whole plant of Glycine tabacina (Labill.) Benth has been used as a traditional herbal medicine to treat rheumatism, ostealgia and nephritis in China. It is also one of the sources of the renowned native herbal medicine ‘I-Tiao-Gung’ in Taiwan.

Aim of the study

This study aimed to investigate the anti-arthritic effect of ethanol extract of G. tabacina (GTE) in a collagen-induced arthritis (CIA) rat model.

Materials and methods

The chemical profile of GTE was analyzed by HPLC-UV. The CIA was induced in male Wistar rats by intradermal injection of bovine type II collagen at tail root, back and ankle joints. The rats were orally administrated daily with GTE (1.11, 2.22 and 4.44 g dry weight of herb powder per kg body weight) from day 0 and continued for 30 days. Swelling volume and thickness of paw, arthritis index, X-radiographs and histopathological changes were examined to assess the severity of arthritis. Furthermore, the levels of pro-inflammatory cytokines, such as interleukin1β (IL-1β), IL-6 and tumor necrosis factor α (TNF-α), total superoxide dismutase (T-SOD) activity and malonaldehyde (MDA) level were measured to preliminarily explore the possible mechanisms.

Results

Oral administration of GTE significantly ameliorated the arthritic symptoms in CIA rat model, as indicated by the effects on paws swelling and arthritis index. X-radiographic analysis and histopathological examinations demonstrated that GTE effectively protected the bone and cartilage of joints from erosion, lesion and deformation. The efficacy of GTE treatment on CIA was comparable to that of indomethacin (positive drug). Besides, the overproduction of IL-1β, IL-6 and TNF-α was remarkably inhibited in the serum of all GTE treatment groups. The restoration of serum T-SOD activity and MDA level proved that GTE administration alleviated the oxidative stress in CIA rats.

Conclusions

GTE exhibited strong anti-CIA activity through inhibiting pro-inflammatory cytokines and oxidation in rats, suggesting its potential preventive and therapeutic effects on rheumatoid arthritis (RA).

Introduction

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases, which is characterized by synovial chronic inflammation and hyperplasia, autoantibody production, cartilage and bone destruction, and systemic features, including cardiovascular, psychological, pulmonary, and skeletal disorders (McInnes and Schett, 2011). It is estimated to affect around 0.5%–1% of the global population, being approximately three times more common in females than males (Smolen et al., 2016; Sardar et al., 2019). The prevalence rate in China is reported to be between 0.2% and 0.37% (Wang et al., 2016a). RA has been ranked as a central contributor to progressive disability worldwide and even leads to early death, bringing a heavy burden to both individuals and society (Cross et al., 2014).

The etiology and pathogenesis of RA are still not fully understood. Evidences suggest that RA involves a complex interplay between genotypes and environmental triggers including smoking and dust (McInnes and Schett, 2011). It is generally believed that autoantibodies production and resulting chronic inflammation and articular destruction are the pathological basis of RA (McInnes and Schett, 2011; Firestein and McInnes, 2017). Pro-inflammatory cytokines, which arises from various synovial cell populations, such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β and IL-6, have been shown to play remarkable roles in synovitis and subsequent joint damage (Rosillo et al., 2016; Chen et al., 2019). Additionally, RA pathogenesis has been reported to be closely associated with oxidative stress, as the overproduction of reactive oxygen species (ROS) is responsible for the tissue injury, elevated pro-inflammatory milieu and eventually sustained disease progression (Shah et al., 2011; Glennon-Alty et al., 2018).

The current therapeutic management of RA is designed to alleviate symptoms by suppressing immune response, inflammation, bone erosion and joint damage. Nonsteroidal anti-inflammatory drugs (NSAIDs), disease modifying anti-rheumatic drugs (DMARDs), glucocorticoids, and biological agents are commonly applied in RA clinical treatment (Scott et al., 2010; Cecchi et al., 2018). Unfortunately, administration of these agents is accompanied by severe side effects such as gastrointestinal disorders, cardiovascular risk and reproductive toxicities (Zampeli et al., 2015). The limited effectiveness, side effects and high costs of current therapies highlight the urgent demand for the development of novel, safe and effective anti-RA agents.

A variety of Chinese herbs have been used in RA treatment for thousands of years. Increasing attention has been attracted to develop anti-RA drugs from Chinese herbs owing to their multiple chemical components, multiple molecular targets and low side effects (Moudgil and Berman, 2014; Lu et al., 2015). Glycine tabacina (Labill.) Benth (family: Leguminosae), named Yan Dou in Chinese, which is a perennial herb, is mainly distributed in the coastal areas of around 25 oN, e.g. southern China, Taiwan, the Ryukyu Islands, and some South Pacific Islands (Huang et al., 2016). G. tabacina has been used for the treatment of rheumatism, ostealgia and nephritis in folk medicine (Li, 2006; Huang et al., 2016). It is one of the sources of the renowned native herbal medicine ‘I-Tiao-Gung’ in Taiwan. Lin et al. (2005) revealed the abundance of four isoflavonoids (daidzin, genistin, daidzein, and genistein) and cinnamaldehyde in this species. Moreover, its aqueous extract has been shown to exert antioxidant, anti-inflammatory, and antidiabetic activities in vitro (Huang et al., 2016). However, there are no further phytochemical and pharmacological studies on this species. In the current study, we found, for the first time, that the ethanol extract of G. tabacina (GTE) exhibited strong anti-collagen-induced arthritis (CIA) in rats, as evidenced by significantly reduced paw volume and thickness, and reduced arthritis-induced bone degeneration and bone erosion in GTE treatment groups. In addition, GTE profoundly decreased the serum levels of IL-1β, IL-6, TNF-α, malonaldehyde (MDA), while increased total superoxide dismutase (T-SOD) in arthritic rats, suggesting that the anti-arthritic activity of GTE is via inhibiting the release of pro-inflammatory cytokines and alleviating oxidative stress.

Section snippets

Plant material and chemicals

The whole plant of G. tabacina was purchased from a local herb farmer (Fuqing, Fujian, China) in September 2015 and identified by Dr. Jianping Han at Chinese Academy of Medical Sciences & Peking Union Medical College (Beijing, China) using a DNA barcoding method (Han et al., 2013). A voucher specimen (ICMS-2015-GT0012) was deposited at the State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macao SAR, China.

Bovine type

HPLC-UV analysis of GTE

The HPLC-UV analysis of GTE (Fig. 2) showed that five common flavonoids were identified by comparing retention times of individual peak with those of the authentic references. The contents of these flavonoids were genistin (1.31%), daidzein (0.27%), genistein (14.50%), pratensein (0.10%) and coumestrol (1.96%).

Effects of GTE on body weight, paw swelling, and arthritis index in CIA rats

To evaluate the therapeutic effect of GTE on collagen-induced arthritis, the weight loss, paw swelling and arthritis index of rats in all groups were determined (Fig. 3). After booster

Discussion

RA is characterized as chronic synovial inflammation caused by autoimmune response, which leads to progressive cartilage and bone destruction, disability and increased risk for systemic complications (Sardar et al., 2019). Since CIA model is easy, reproducible and closely similar to pathological characteristics of human RA, it is widely used for anti-RA drug screening and RA pathogenesis studies (Brand et al., 2007). Therefore, in the present study, a CIA rat model was selected and established

Conclusion

In summary, the present investigation demonstrated that the oral administration of GTE significantly ameliorated the arthritic symptoms in CIA rat model, e.g. markedly alleviated paw swelling, arthritis index, bone erosion and deformation of joint. The anti-arthritic effect of GTE might be attributed to its ability to suppress the release of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and alleviate the oxidative stress. Our findings provide important information for the development of

Abbreviations

RA, rheumatoid arthritis; IL-1β, interleukin 1β; IL-6, interleukin 6; TNF-α, tumor necrosis factor α; ROS, reactive oxygen species; NSAIDs, Nonsteroidal anti-inflammatory drugs; DMARDs, disease modifying anti-rheumatic drugs; GTE, ethanol extract of G. tabacina; CIA, collagen-induced arthritis; MDA, malonaldehyde; T-SOD, total superoxide dismutase; CII, bovine type II collagen; CFA, Complete Freund's Adjuvant; HE, hematoxylin-eosin; ELISA, enzyme-linked immunosorbent assay.

Authors' contributions

YT, KW and CH conceived and designed the study; KW, YL, YT, XJ and LW performed the experiments; KW, YT, JH, JW and CH analyzed the data; YT and CH drafted the manuscript. All the authors have read and approved the final manuscript prior to submission.

Conflicts of interest

The authors declare that there are no conflicts of interest.

Acknowledgements

This work was supported by the Macao Science and Technology Development Fund (FDCT/070/2017/A2 and FDCT/041/2016/A) and the Research Fund of the University of Macau (MYRG2018-00176-ICMS).

References (40)

  • S. Ahmad et al.

    Anti-arthritogenic and cardioprotective action of hesperidin and daidzein in collagen-induced rheumatoid arthritis

    Mol. Cell. Biochem.

    (2016)
  • O. Altindag et al.

    Increased DNA damage and oxidative stress in patients with rheumatoid arthritis

    Clin. Biochem.

    (2007)
  • G. Bhattarai et al.

    Anti-inflammatory, anti-osteoclastic, and antioxidant activities of genistein protect against alveolar bone loss and periodontal tissue degradation in a mouse model of periodontitis

    J. Biomed. Mater. Res. A

    (2017)
  • D.D. Brand et al.

    Collagen-induced arthritis

    Nat. Protoc.

    (2007)
  • F.M. Brennan et al.

    Evidence that cytokines play a role in rheumatoid arthritis

    J. Clin. Investig.

    (2008)
  • I. Cecchi et al.

    Neutrophils: novel key players in Rheumatoid Arthritis. Current and future therapeutic targets

    Autoimmun. Rev.

    (2018)
  • Z. Chen et al.

    Anti-inflammatory and immune-regulatory cytokines in rheumatoid arthritis

    Nat. Rev. Rheumatol.

    (2019)
  • M. Cross et al.

    The global burden of rheumatoid arthritis: estimates from the Global Burden of Disease 2010 study

    Ann. Rheum. Dis.

    (2014)
  • G.S. Firestein et al.

    Immunopathogenesis of rheumatoid arthritis

    Immunity

    (2017)
  • L. Glennon-Alty et al.

    Neutrophils and redox stress in the pathogenesis of autoimmune disease

    Free Radic. Biol. Med.

    (2018)
  • J. Han et al.

    The short ITS2 sequence serves as an efficient taxonomic sequence tag in comparison with the full-length ITS

    BioMed Res. Int.

    (2013)
  • G. Huang et al.

    Curcumin protects against collagen-induced arthritis via suppression of BAFF production

    J. Clin. Immunol.

    (2013)
  • S.S. Huang et al.

    Antioxidants, anti-inflammatory, and antidiabetic effects of the aqueous extracts from Glycine species and its bioactive compounds

    Bot. Stud.

    (2016)
  • Y. Hu et al.

    Study in treatment of collagen-induced arthritis in DBA/1 mice model by genistein

    Curr. Pharmaceut. Des.

    (2016)
  • S. Karieb et al.

    Phytoestrogens directly inhibit TNF-α-induced bone resorption in RAW264. 7 cells by suppressing c-fos-induced NFATc1 expression

    J. Cell. Biochem.

    (2011)
  • S.S. Laev et al.

    Anti-arthritic agents: progress and potential

    Bioorg. Med. Chem.

    (2015)
  • H. Li et al.

    Isotrifoliol inhibits pro-inflammatory mediators by suppression of TLR/NF-κB and TLR/MAPK signaling in LPS-induced RAW264. 7 cells

    Int. Immunopharmacol.

    (2017)
  • T.S.C. Li

    Taiwanese Native Medicinal Plants: Phytopharmacology and Therapeutic Values

    (2006)
  • S.J. Lin et al.

    Contents of certain isoflavones in Glycine dolichocarpa, G. tabacina and G. tomentella collected in Taiwan

    J. Food Drug Anal.

    (2005)
  • S.W. Lu et al.

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

    J. Ethnopharmacol.

    (2015)
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