In Vitro Antiviral Activity of Rooibos Tea (Aspalathus linearis) Leaves Aqueous Extract against Influenza Virus

Mona T. Idriss1, Abdelgadir A. Abdelgadir2*, Abdurahman H. Nour3

1Department of Pharmaceutics, Imperial University College, Elriyad, Khartoum, Sudan
2Department of Pharmacognosy, Faculty of Pharmacy, University of Gezira, Wad Medani, Sudan. 
3Faculty of Chemical and Natural Resources Engineering University, Pahang, Malaysia.

Corresponding Author:; Tel: +249912554791
Recieved Date: 15 February 2021; Accepted Date: 06 April 2021; Published Date: 03 May
Citation: Idriss MT, Abdelgadir AA, Nour AH. In Vitro Antiviral Activity of Rooibos Tea (Aspalathus linearis) Leaves Aqueous Extract against Influenza Virus. Trop J Nat Prod Res. 2021; 5(4): 686-691.
© 2021 Gassab et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Influenza virus infection is a major public health problem and its control continues to be a challenge. The emergence of highly resistant-influenza virus strains necessitates the need to search for novel medications, especially from natural sources. The aim of this study was to identify the anti-influenza virus activity of Rooibos tea (Aspalathus linearis) aqueous extract and possible mechanisms of action on different virus strains. Anti-influenza activity was performed using standard in vitro assays including cell-based neutralization by inhibition of virus-induced cytopathic effect (CPE), inhibition of viral plaques and hemagglutination assay. The CPE was determined visually and by dye uptake. The time-of-addition assay was performed to determine the effect on the virus life cycle. The results reveal that the extract showed a significant broad spectrum of anti-influenza activity against both influenza A and B with 50% inhibitory concentration (IC50) of 1.3 mg/mL, while the 50% cytotoxic concentration (CC50) was 40 mg/mL. The inhibitory effect of extract was identified against influenza A/PR/8/34 (H1N1), A/WSN/33 and A/HK/8/68 (H3N2) and influenza B virus strains. The virus-induced cytopathic effects were significantly reduced. Plaque assays indicated that the extract markedly reduced virus infectivity in a dose-dependent manner. Results of this study indicated that the extract directly affected virus particles and disrupts the function of virus adsorption to host cells. Rooibos tea extract strongly inhibits influenza virus replication with a dual mode of action and may contribute to the development of a new anti-influenza virus agent.

Keywords: Cytotoxicity, Influenza A virus, Plaque assay, Rooibos tea, Time of addition assay.
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ISSN: 2616-0684 (Print)
ISSN: 2616-0692 (Online)
DOI: 10.26538/tjnpr
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