Antiviral Activity of the Rhamnolipids Mixture from the Antarctic Bacterium Pseudomonas gessardii M15 against Herpes Simplex Viruses and Coronaviruses.

Rosa Giugliano,Gianluigi Franci,Donatella De Pascale,Carmine Buonocore,Pietro Tedesco,Fortunato Palma Esposito,Anna De Filippis,Annalisa Chianese,Massimiliano Galdiero,Carla Zannella

doi:10.3390/pharmaceutics13122121

Abstract

Emerging and re-emerging viruses represent a serious threat to human health at a global level. In particular, enveloped viruses are one of the main causes of viral outbreaks, as recently demonstrated by SARS-CoV-2. An effective strategy to counteract these viruses could be to target the envelope by using surface-active compounds. Rhamnolipids (RLs) are microbial biosurfactants displaying a wide range of bioactivities, such as antibacterial, antifungal and antibiofilm, among others. Being of microbial origin, they are environmentally-friendly, biodegradable, and less toxic than synthetic surfactants. In this work, we explored the antiviral activity of the rhamnolipids mixture (M15RL) produced by the Antarctic bacteria Pseudomonas gessardii M15 against viruses belonging to Coronaviridae and Herpesviridae families. In addition, we investigated the rhamnolipids’ mode of action and the possibility of inactivating viruses on treated surfaces. Our results show complete inactivation of HSV-1 and HSV-2 by M15RLs at 6 µg/mL, and of HCoV-229E and SARS-CoV-2 at 25 and 50 µg/mL, respectively. Concerning activity against HCoV-OC43, 80% inhibition of cytopathic effect was recorded, while no activity against naked Poliovirus Type 1 (PV-1) was detectable, suggesting that the antiviral action is mainly directed towards the envelope. In conclusion, we report a significant activity of M15RL against enveloped viruses and demonstrated for the first time the antiviral effect of rhamnolipids against SARS-CoV-2.

Highlights

IntroductionViruses can be structurally divided in two groups according to the presence or not of lipids as integral components of their superficial structure [1]
The antiviral activity of the M15RL mixture produced by P. gessardii M15 was first
The antiviral activity of the M15RL mixture produced by P. gessardii M15 was first investigated against Herpes simplex virus type 1 (HSV-1) and Human coronaviruses (HCoV)-229E in both co-treatment and virus pre-treatment investigated against HSV-1 and HCoV-229E in both co-treatment and virus pre-treatment experiments through the quantification of plaques reduction

Summary

Introduction

Viruses can be structurally divided in two groups according to the presence or not of lipids as integral components of their superficial structure [1] Viruses acquire these lipids during viral assembly and exit from the infected cell, generally through a buddings mechanism, which leads to the formation of a membrane that envelops the capsid containing the viral genome [2]. This lipidic layer, called the viral envelope, is shared by many different families of viruses, such as retrovirus, herpesvirus, coronavirus, orthomyxovirus, rhabdovirus, filovirus, and paramyxovirus, despite the great diversity in their structure, replication strategy, pathogenesis, host-range, and diseases that they cause [3].

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