Elsevier

Archives of Oral Biology

Volume 132, December 2021, 105280
Archives of Oral Biology

Moringa oleifera Lam. leaf extract safely inhibits periodontitis by regulating the expression of p38α/MAPK14-OPG/RANKL

https://doi.org/10.1016/j.archoralbio.2021.105280Get rights and content

Highlights

  • This is the first report of the anti-PD efficiency of MOL by regulating p38α-OPG/RANKL pathway.

  • Eighty-eight phenolic compounds were identified in MOL using UPLC-ESI-MS/MS analysis.

  • MOL regulated inflammation cytokines expression and alveolar bone resorption in vivo and vitro.

  • Network pharmacology coupled with experimental validation is an effective way to find new drugs.

Abstract

Periodontitis is a chronic disease clinically defined by loss of alveolar bone and connective tissue degeneration. Although Moringa oleifera Lam. (MO), a tree belonging to the Moringacea family, is widely used as an anti-inflammatory agent, its effect on periodontitis is still unclear. In this work, the phenol compounds in MO leaf extract (MOL) were identified by UPLC-ESI-MS/MS, and the anti-periodontitis effects and mechanism of MOL were predicted using network pharmacology and molecular docking. Moreover, the cytotoxic, antioxidant, and anti-periodontitis properties of MOL were confirmed in vivo and in vitro. In total, 88 phenolic compounds and 234 potential MOL periodontitis targets were screened, involving 2916 biological processes (BP). The p38α MAPK (MAPK14) pathway and OPG/RANKL complex were predicted to be involved in the process of molecular docking. Furthermore, experimental validation suggested that MOL significantly ameliorated inflammation and reduced alveolar bone resorption. The OPG/RANKL ratio was regulated through the inhibition of MAPK14, and the anti-periodontitis effect was realized by the antioxidant properties of MOL. Hematoxylin and eosin (H&E) staining of rat vital organs and the survival rate of RAW 264.7 cells confirmed the safety of MOL. The present study provides valuable insights into how MOL reduces inflammation and alveolar bone resorption associated with periodontitis. In conclusion, MOL safely inhibits chronic periodontitis highly likely by regulating the expression of p38α/MAPK14-OPG/RANKL. Network pharmacology coupled with experimental validation is an effective way to find new drugs in the future.

Data availability statement

The original data presented in the study are included in the article. Further inquiries can be directed to the corresponding authors.

Introduction

Periodontitis is a chronic inflammatory disease related to some other chronic diseases, such as cancer (Michaud et al., 2018). It greatly affects human health, especially in children and young adults. In later stages, the disease leads to the destruction of supporting tissues and the loss of teeth through alveolar bone resorption (Carvalho-Filho et al., 2016). Porphyromonas gingivalis (P. gingivalis) is a pathogen causing periodontitis, the lipopolysaccharide (LPS) of P. gingivalis promotes the production of proinflammatory factors that upregulate RANKL—an osteoclast differentiating factor that causes bone loss—and that OPG is a decoy receptor of RANKL, the OPG/RANKL ratio has extensively been used as an index of bone formation and resorption (Pinto et al., 2020). Furthermore, previous studies have reported that p38α MAPK signaling is associated with osteogenesis and the expression of inflammatory cytokines in periodontitis (Sabbieti et al., 2010, Schwab et al., 2018). In this study, the roles and interaction between p38α MAPK signaling and OPG/RANKL in periodontitis were investigated.

At present, the use of natural compounds for periodontitis treatment is favored due to their harmless nature and antimicrobial activities (Chu, Ma, Sun, Xu, & Zhang, 2020). Moringa oleifera Lam. (MO), a fast-growing tree of the Moringacea family, is widely distributed in many countries. This tree is rich in proteins, vitamins, antioxidants, and phenolic acids (Kou, Li, Olayanju, Drake, & Chen, 2018), and its leaf extract exhibits inhibitory effects against some chronic diseases, especially inflammatory diseases, including ulcerative colitis (Kim et al., 2017) and arthritis (Saleem, Saleem, Akhtar, & Shahzad, 2020). Despite the established medicinal effects of MO leaf extract (MOL), its activity against periodontitis remains unknown.

Network pharmacology is a multidisciplinary methodology that relies on “syndrome differentiation” in evaluating multitarget herbal medicines that tend to be more effective than the commonly known single-target drugs. Herein, network pharmacology analysis and molecular docking (Saenkham et al., 2020) were used to explore the potential effect of MOL against periodontitis and to elucidate the underlying mechanism. Furthermore, these results were verified by in vivo and in vitro experiments.

Section snippets

Preparation of fractions

MO PKM1 leaves (CATAS-056) were identified and provided by the Chinese Academy of Tropical Agricultural Sciences (Zhanjiang, Guangdong, China) in November 2017. A voucher specimen of these leaves had been deposited in the Academy herbarium. Dried MO leaf powder (1000 g, water content <8%) was extracted in water (liquid/solid ratio of 20:1 v/m, mL/g) at 60 °C for 1 h. Subsequently, the supernatant was collected, and the residue was re-extracted twice. The combined supernatant was concentrated

Characterization of the chemical constituents in MOL

UPLC-ESI-MS/MS (Solarbio Biotechnology Co. Ltd., Shanghai, China) was used to identify the phenol compounds in MOL based on retention time and response values. Considering that the response values of the test compounds were higher in the negative ion mode than in the positive ion mode, only the former was used for the identification of these compounds. In total, 88 phenolics were detected, and they were all eluted at a retention time between 3 and 32 min (Fig. 1). These data confirmed that

Conclusion

We reported data in support of the hypothesis that MOL provides anti-periodontitis activity highly likely by regulating the p38α/MAPK14-OPG/RANKL pathway. Our findings showed that MOL not only altered the expression of inflammatory cytokines but also significantly reduced alveolar bone resorption in vivo and in vitro. As such, MOL can be used to clinically treat periodontitis, a chronic inflammatory disease that is associated with some other chronic diseases. It is worth noting that network

Funding

This study was financially supported by the Natural Science Foundation of China (Grant No. 81960200) and Distinguished Young Scholars of Jiangxi Province (Grant No. 20171BCB23090).

CRediT authorship contributions statement

The statement is accurate and agreed by all authors. Sang Long: Conceptualization, Methodology, Software, Jie Zhang: Methodology, Supervision, Funding acquisition, Fang Wang: Visualization, Writing – original draft, Writing - review & editing.

Author contributions

MOL was extracted by FW. The applications of MOL in vivo and in vitro were investigated by SL. The manuscript was written and reviewed by FW. All of the experiments were supervised by JZ. All of the authors contributed to the article and approved the submitted version.

Acknowledgments

We gratefully acknowledge the identification and provision of MO by the Chinese Academy of Tropical Agricultural Sciences (Zhanjiang, Guangdong, China).

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