Viruses are microscopic pathogens capable of causing
disease and
are responsible for a range of human mortalities and morbidities worldwide.
They can be rendered harmless or destroyed with a range of antiviral
chemical compounds. Cucurbit[
n
]urils (CB[
n
]s) are a family of macrocycle chemical compounds existing
as a range of homologues; due to their structure, they can bind to
biological materials, acting as supramolecular “hosts”
to “guests”, such as amino acids. Due to the increasing
need for a nontoxic antiviral compound, we investigated whether cucurbit[
n
]urils could act in an antiviral manner. We have found
that certain cucurbit[
n
]uril homologues do indeed
have an antiviral effect against a range of viruses, including herpes
simplex virus 2 (HSV-2), respiratory syncytial virus (RSV) and SARS-CoV-2.
In particular, we demonstrate that CB[7] is the active homologue of
CB[
n
], having an antiviral effect against enveloped
and nonenveloped species. High levels of efficacy were observed with
5 min contact times across different viruses. We also demonstrate
that CB[7] acts with an extracellular virucidal mode of action via
host–guest supramolecular interactions between viral surface
proteins and the CB[
n
] cavity, rather than via cell
internalization or a virustatic mechanism. This finding demonstrates
that CB[7] acts as a supramolecular virucidal antiviral (a mechanism
distinct from other current extracellular antivirals), demonstrating
the potential of supramolecular interactions for future antiviral
disinfectants.