bims-antpol 2024-08-25 papers

Issue of 2024–08–25
three papers selected by
Rick Sheridan, EMSKE Phytochem

Front Microbiol. 2024 ;15 1443183

Hyperforin, the major metabolite of St. John's wort, exhibits pan-coronavirus antiviral activity.

Imelda Raczkiewicz, Céline Rivière, Peggy Bouquet, Lowiese Desmarets, Audrey Tarricone, Charline Camuzet, Nathan François, Gabriel Lefèvre, Fabiola Silva Angulo, Cyril Robil, François Trottein, Sevser Sahpaz, Jean Dubuisson, Sandrine Belouzard, Anne Goffard, Karin Séron.

Introduction: The COVID-19 pandemic caused by the SARS-CoV-2 virus has underscored the urgent necessity for the development of antiviral compounds that can effectively target coronaviruses. In this study, we present the first evidence of the antiviral efficacy of hyperforin, a major metabolite of St. John's wort, for which safety and bioavailability in humans have already been established.
Methods: Antiviral assays were conducted in cell culture with four human coronaviruses: three of high virulence, SARS-CoV-2, SARS-CoV, and MERS-CoV, and one causing mild symptoms, HCoV-229E. The antiviral activity was also evaluated in human primary airway epithelial cells. To ascertain the viral step inhibited by hyperforin, time-of-addition assays were conducted. Subsequently, a combination assay of hyperforin with remdesivir was performed.
Results: The results demonstrated that hyperforin exhibited notable antiviral activity against the four tested human coronaviruses, with IC50 values spanning from 0.24 to 2.55 µM. Kinetic studies indicated that the observed activity occur at a post-entry step, potentially during replication. The antiviral efficacy of hyperforin was additionally corroborated in human primary airway epithelial cells. The results demonstrated a reduction in both intracellular and extracellular SARS-CoV-2 viral RNA, confirming that hyperforin targeted the replication step. Finally, an additive antiviral effect on SARS-CoV-2 was observed when hyperforin was combined with remdesivir.
Discussion: In conclusion, hyperforin has been identified as a novel pan-coronavirus inhibitor with activity in human primary airway epithelial cells, a preclinical model for coronaviruses. These findings collectively suggest that hyperforin has potential as a candidate antiviral agent against current and future human coronaviruses.

Keywords: antiviral; broad-spectrum; coronaviruses; natural compound; replication

DOI: https://doi.org/10.3389/fmicb.2024.1443183

Heliyon. 2024 Aug 15. 10(15): e35630

Exploring the potency of polyphenol-rich blend from Lonicera caerulea var. Kamtschatica sevast., Aronia melanocarpa, and Echinacea purpurea: Promising anti-inflammatory, antioxidant, and antiviral properties.

Katarzyna Zima, Barbara Khaidakov, Marta Sochocka, Michał Ochnik, Krzysztof Lemke, Paulina Kowalczyk.

Previous studies have highlighted the beneficial properties of plants rich in polyphenols, such as Lonicera caerulea var. Kamtschatica Sevast. (LCK), Aronia melanocarpa (AM), and Echinacea purpurea (EP). These plants have demonstrated antioxidant, immunomodulatory, and potential antiviral effects. Thus, the objective of this study was to investigate the impact of the ELA blend, a polyphenol-rich blend containing EP, LCK, and AM, on the cellular mechanisms involved in viral infection. To assess the effects of the ELA blend, various experiments were conducted using A549 cells and a mucociliary tissue 3D model called EpiAirway™. Inflammation and oxidative stress induced by LPS were evaluated through measurements of SOD activity, ELISA, and qPCR analysis. Additionally, antiviral assays were performed in a cell-present environment to examine the blend's effectiveness against HCoV-OC43. The results showed that the ELA blend-treated group exhibited reduced expression of IL1B, CXCL8, ICAM1, MCP1, and RELA in both A549 cells and EpiAirway™. Moreover, the blend enhanced the expression of CAT, HMOX1, SOD1, and SOD2 in A549 cells. The antiviral activity of the ELA blend was also investigated, i.e. its influence on viral replication cycle, to determine the potential as an antiviral preparation. At the highest non-cytotoxic concentration, the ELA blend demonstrated a 87.5 % reduction in viral titer when administered simultaneously with HCoV-OC43. It emphasize potential ability of the preparation to block viral entry to the host cells. At the same time, ELA blend did not express virucidal activity, i.e. inactivation of free viral particles, against HCoV-OC43. In conclusion, ELA blend displayed antiviral activity and exhibited immunomodulatory and antioxidant effects. Based on these findings, it can be concluded that ELA blend has potential for the prevention and treatment of viral infections.

Keywords: Antioxidant; Antiviral activity; Immunomodulation; Plant extracts; Polyphenol

DOI: https://doi.org/10.1016/j.heliyon.2024.e35630

J Appl Microbiol. 2024 Aug 22. pii: lxae221. [Epub ahead of print]

Evaluation of inhibitory activity of essential oils and natural extracts on foodborne viruses.

Mariem Amri, Éric Jubinville, Valérie Goulet-Beaulieu, Ismail Fliss, Julie Jean.

AIMS: Enteric viruses are recognized as a major concern in health care and in the food sector in Canada. Novel clean-label strategies for controlling enteric viruses are sought in the food industry. In this study, we examined the antiviral potential of plant extracts and essential oils on murine norovirus 1 (MNV-1), hepatitis A virus (HAV) and herpes simplex 1 (HSV-1).
METHODS AND RESULTS: Inactivation of the viruses by grape seed, blueberry, green tea, and cranberry extracts and by rosemary and thyme essential oils was measured using plaque formation assay. Concentrations ranging from 50 to 200,000 ppm with a contact time of 90 min were tested. Grape seed extract at 10,000 ppm was the most effective (p < 0.05) at reducing MNV-1 and HAV infectious titers, respectively by 2.85 ± 0.44 log10 and 1.94 ± 0.17 log10. HSV-1 titer was reduced by 3.81 ± 0.40 log10 at 1000 ppm grape seed extract.
CONCLUSIONS: Among the plant products tested, grape seed extract was found the most effective at reducing the infectious titers of MNV-1, HAV and HSV.

Keywords: Viral inactivation; antiviral; essential oil; foodborne viruses; plant extract

DOI: https://doi.org/10.1093/jambio/lxae221