Treatment with onion bulb extract both prevents and reverses allergic inflammation in a murine model of asthma

Abstract

Context

Asthma presents a global health challenge. The main pharmacotherapy is synthetic chemicals and biological-based drugs that are costly, and have significant side effects. In contrast, use of natural products, such as onion (Allium cepa L., Amaryllidaceae) in the treatment of airway diseases has increased world-wide because of their perceived efficacy and little safety concerns. However, their pharmacological actions remain largely uncharacterized.

Objective

We investigated whether onion bulb extract (OBE) can (1) reverse established asthma phenotype (therapeutic treatment) and/or (2) prevent the development of the asthma phenotype, if given before the immunization process (preventative treatment).

Materials and methods

Six groups of male Balb/c mice were established for the therapeutic (21 days) and five groups for the preventative (19 days) treatment protocols; including PBS and house dust mite (HDM)-challenged mice treated with vehicle or OBE (30, 60, and 100 mg/kg/i.p.). Airways inflammation was determined using cytology, histology, immunofluorescence, Western blot, and serum IgE.

Results

Therapeutic (60 mg/kg/i.p.) and preventative (100 mg/kg/i.p.) OBE treatment resulted in down-regulation of HDM-induced airway cellular influx, histopathological changes and the increase in expression of pro-inflammatory signaling pathway EGFR, ERK1/2, AKT, pro-inflammatory cytokines and serum IgE.

Discussion and Conclusion

Our data show that OBE is an effective anti-inflammatory agent with both therapeutic and preventative anti-asthma effects. These findings imply that onion/OBE may be used as an adjunct therapeutic agent in established asthma and/or to prevent development of allergic asthma. However, further studies to identify the active constituents, and demonstrate proof-of-concept in humans are needed.

Keywords:

• House dust mite
• signaling pathways
• EGFR
• AKT
• erk1/2
• a
• nd IgE

Acknowledgements

The authors are thankful to the support of Mr. Sunny Ojoko and Mr. Hecktor Velasco from the Animal Resources Center of Health Sciences Center. We are also grateful for Ms Seena Mathews for technical and scientific contribution in this study and we are also grateful to Al-Shaimaa A. Al-Kandery for proof-reading the manuscript.

Authors’ Contributions

Ahmed Z. El-Hashim: Project administration, Funding acquisition, Supervision, Writing – original draft, Writing – review & editing, Formal Analysis. Maitham A. Khajah; Conceptualization, Supervision, Formal Analysis, Writing – review & editing, Khaled Y. Orabi; Conceptualization, Supervision, Formal Analysis, Writing – review & editing, Sowmya Balakrishnan; Methodology, Formal Analysis, Hanan G. Sary; Methodology, Formal Analysis, Ahmad M. Barakat; Methodology, Formal Analysis.

Disclosure statement

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the [Kuwait Foundation for the Advancement of Sciences] under grant [number P11613PT01]; and parts of this work was supported by the [Research Unit for Genomics, Proteomics and Cellomics Studies (OMICS), Kuwait University] under grant [number SRUL02/13].