3 | MNPs: NOVEL BIOMEDICAL RESOURCES FOR ANTI-INFECTION
OF 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 (Table 1), 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 [28]. Marine bacteria and fungi-derived bioactive 15
compounds showed promising potential roles against SARS-CoV-2 RNA
dependent RNA polymerase and methyltransferase [29]. Some new MNPs
compounds (bioactive peptides) isolated from marine organisms (such as
vertebrates, invertebrates, seaweeds, or other sea microorganisms) have
a role of prevention on SARS-CoV-2 infection due to potential
angiotensin converting enzyme (ACE) inhibition and anti-hypertensive
activities [30]. The most potent marine-derived metabolite from
Red-Sea invertebrates, erylosides B [31], showed a great inhibitor
activity against the SARS-CoV-2 Mpro.
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 [32]. A naturally existing sulfated polysaccharide,
lmbda-carrageenan, 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 [33]. 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 [34]. As
potential candidates of antiviral drug, marine sulfated polysaccharides
can be used to prevent SARS-CoV-2 infection [35].
Carbohydrate-binding agents 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
[36]. Marine-derived natural metabolites from the soft coral
[Nephthea sp.] can also be developed potential SARS-CoV-2
protease inhibitors [37]. 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 [38].
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 [39]. The
nontoxic and non-immunogenic polyphosphate, a physiological, metabolic
energy (ATP)-providing polymer, could possibly also exert a protective
effect against SARS-CoV-2-cell attachment [40]. 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 and its major variants (Delta and Omicron). Hence, the
MNPs and their derivatives could be a promising source of structurally
diverse new anti-RNA virus therapeutics [41].