Ocean & seas: Novel biomedical resources for anti-SARS-CoV-2
As an enveloped RNA virus, coronavirus is a major cause of human
respiratory diseases. The spike glycoprotein (SGP) is known as the main
target of antibodies having neutralizing potency and is also considered
as an attractive target for therapeutic or vaccine development. MNPs as
key and novel biomedical resources for the discovery of drugs to combat
the COVID-19 pandemic, will be more and more valuable.
Among MNPs library, 17 potential SARS-CoV-2 main protease
(Mpr) inhibitors have been identified by
structure-based techniques, and one of these compounds could be
bioactive [25]. Marine bacteria and fungi-derived bioactive 15
compounds showed promising potential roles against SARS-CoV-2 RNA
dependent RNA polymerase (RdRp) and methyltransferase (nsp16) [26].
Some new MNPs compounds (bioactive peptides) isolated from marine
organisms (such as vertebrates, invertebrates, seaweeds, or sea
microorganisms) have a role of prevention on SARS2-Cov infection due to
potential ACE inhibition and anti-hypertensive activities [27].
For example, some bioactive agents from marine polysaccharides and
polysaccharide-based vaccine adjuvants were developed for the fight
against SARS-CoV-2 and were used as therapeutic agents and vaccines of
COVID-19 [28]. A naturally existing sulfated polysaccharide,
lmbda-carrageenan (λ-CGN), purified from marine red algae, could be a
promising antiviral agent for preventing infection with several
respiratory viruses since this polyanionic compound exerts antiviral
activity by targeting viral attachment to cell surface receptors and
preventing virus entry [29]. Novel marine sulfated polysaccharides
can be developed further for prophylactic as well as therapeutic
purposes due to potent anti-SARS-CoV-2 activity and affinity to the SGP
[30].
Carbohydrate-binding agents (CBAs) from MNPs like lectins from marine
algae have shown antiviral activities against SARS-CoV-2 due to
targeting of N-linked glycans of the SGP envelope of CoV, and could also
serve as an attractive therapeutic approach for developing novel
antivirals [31]. As SARS-CoV-2 Mpro inhibitors,
five MNPs (a benzo[f]pyrano[4,3-b]chromene, notoamide I,
emindole SB beta-mannoside, and two bromoindole derivatives) were the
most promising marine drug-like leads [32].
Up-to-date, FDA-approved marine drugs have the potential to inhibit the
biological activity of SARS-CoV-2 main protease since they can bind at
its active site and displace water molecules at this site [33]. The
nontoxic and non-immunogenic polyphosphate (polyP), a physiological,
metabolic energy (ATP)-providing polymer, could possibly also exert a
protective effect against SARS-CoV-2-cell attachment [34].
Thus, these marine drugs which are already in clinical use for cancer
treatment can also be used as a potential alternative to prevent and
treat infected individuals with SARS-CoV-2. Hence, the MNPs and their
derivatives could be a promising source of structurally diverse new
anti-RNA virus therapeutics [35].