Effect of hot water extracts of Arthrospira maxima (spirulina) against respiratory syncytial virus

Wei Chen; Yi-Hsiang Chen; Ya-Chun Liao; Xin-Wen Huang; Ting-Jang Lu; Shin-Ru Shih

doi:10.1016/j.phymed.2022.154611

Effect of hot water extracts of Arthrospira maxima (spirulina) against respiratory syncytial virus

Phytomedicine. 2023 Feb:110:154611. doi: 10.1016/j.phymed.2022.154611. Epub 2022 Dec 17.

Authors

Wei Chen¹, Yi-Hsiang Chen², Ya-Chun Liao², Xin-Wen Huang³, Ting-Jang Lu⁴, Shin-Ru Shih⁵

Affiliations

¹ Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
² Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
³ Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan.
⁴ Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan. Electronic address: tjlu@ntu.edu.tw.
⁵ Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Research Center for Chinese Herbal Medicine, Research Center for Food and Cosmetic Safety, and Graduate Institute of Health Industry Technology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan. Electronic address: srshih@mail.cgu.edu.tw.

PMID: 36580819
DOI: 10.1016/j.phymed.2022.154611

Abstract

Background: Spirulina (Arthrospira maxima) hot water extracts such as calcium spirulan (Ca-SP) have demonstrated antiviral effects against herpes simplex virus (HSV), human immunodeficiency virus-1 (HIV-1), and influenza virus infections. There is no prior evidence suggesting the anti-viral activity of the spirulina hot water extract against respiratory syncytial virus (RSV).

Purpose: There are currently no effective antivirals available to treat RSV infection. Therefore, the development of safe and novel anti-RSV drugs is urgent and necessary. The aim of this work was to demonstrate the anti-RSV activity of spirulina hot water extracts and determine the potential mechanism of action.

Methods: Cytotoxicity and anti-RSV activity of spirulina hot water extracts were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and neutralization assays, respectively. Potential mechanisms and components were assessed using time of addition, attachment, internalization, pull-down assays, and composition analysis.

Results: The polysaccharide-enriched high-molecular weight fraction (>100 kDa, SHD1) had a high total sugar content, with rhamnose accounting for approximately 60 mol% of total monosaccharides. The main glycosyl linkages included 3-, 4-, and 2,3-rhamnopyranosyl linkages. All spirulina hot water extracts showed no toxicity toward human epithelial type 2 (HEp-2) cells but demonstrated anti-RSV activity. The SHD1 had a half maximal effective concentration (EC₅₀) of 0.0915 mg/ml and a selective index (SI) of >261.5 against RSV. SHD1 significantly reduced viral yield in a dose-dependent manner during the RSV attachment stage. SHD1 disrupted RSV internalization and inhibited RSV attachment (G) protein binding to heparan sulfate receptors on the host cell surface, thus preventing RSV attachment and entry.

Conclusion: SHD1 serves as an effective candidate for novel drug development against RSV infection.

Keywords: Antiviral activity; Arthrospira maxima; Respiratory syncytial virus; Water extract.

MeSH terms

Antiviral Agents / pharmacology
Antiviral Agents / therapeutic use
Humans
Respiratory Syncytial Virus Infections* / drug therapy
Respiratory Syncytial Virus Infections* / metabolism
Respiratory Syncytial Viruses
Spirulina*

Substances

Antiviral Agents