2 | MNPs: HUGE BIOMEDICAL RESOURCES FOR ANTI-INFECTION
As biomedical scientists, we know that marine products are beneficial to
human health. The scientists are developing chemicals and novel
therapeutic drugs from MNPs with anti-tuberculosis activity and H.
pylori infection [6, 7], and defensive effects against viral
infection, including the SARS-CoV-2 and HIV-1 [8, 9]. We expect that
these compounds could be employed to treat and prevent infectious
diseases (Table 1), including COVID-19 and
acquired immunodeficiency syndrome (AIDS), if truly having significant
antiviral activities. However, there are still huge challenges in the
discovery and development of marine drugs.
The crude extracts from marine organisms contain compounds capable of
inhibiting inflammation and potential bioactive molecules [10].
Echinochrome pigment extracted from sea urchin has an insightful
antiulcer healing effect [11]. Bis (3-bromo-4,5-dihydroxybenzyl)
ether
(C14H12Br2O5),
a novel bromophenol isolated from the red alga Polysiphonia morrowii
[12], is useful for treating inflammatory diseases due to the
inhibition of LPS-induced inflammation in macrophage cells by inhibiting
the ROS-mediated ERK signaling pathway and reducing inflammatory
mediators.
As we known, MNPs are important biomedical resources for anti-infection.
There are more than 1600 new steroidal structures isolated from marine
organisms. Some steroids can regulate the farnesoid X receptor and the
pregnane X receptor. Their novel agonists and antagonists can target
human diseases, e.g., intestinal inflammation [13]. Marine
invertebrate glycans (Sea squirts or ascidians and sea cucumbers) could
be used as starting material for new therapeutics due to anticoagulant
activity and anti-inflammation [14].
Sea cucumbers are widely consumed in traditional medicine and food.
Holothuria grisea agglutinin has demonstrated the ability to modulate
the inflammatory response in models of inflammation in vivo. Moreover,
it is the first marine invertebrate lectin that showed an
anti-inflammatory effect [15]. Fucosylated chondroitin sulfate
extracted from the sea cucumber Holothuria forskali, as an inhibitor of
selectin interactions, plays vital roles in inflammation and metastasis
progression [16]. Sea cucumbers-derived sterol sulfate effectively
attenuated inflammation by increasing serum adiponectin and reducing
pro-inflammatory cytokine release [17].
A novel cathelicidin from the sea snake Hydrophis cyanocinctus, has
potent both antimicrobial and anti-inflammatory activity by inhibiting
the lipopolysaccharide (LPS)-induced production of nitric oxide (NO) and
pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α),
Interleukin (IL)-1beta, and IL-6, is a potent candidate for the
development of peptide antibiotics [18]. A small-molecule compound
isolated from marine-derived fungus, bis-N-norgliovictin, significantly
inhibits LPS (ligand of TLR4)-induced TNF-α production, and exhibits
potent anti-inflammatory effect both in vitro and in vivo [19].
Hence, it can be a useful therapeutic candidate for the treatment of
sepsis and other inflammatory diseases.
One of MNPs, marine cyanobacterium Lyngbya majuscule has a strong
concentration-dependent anti-inflammatory activity by selectively
inhibition the MyD88-dependent pathway [20]. As a novel marine
metabolite isolated from the sponge Fasciospongia cavernosa,
Cacospongionolide B showed topical anti-inflammatory activity and
reduced the inflammatory response of adjuvant arthritis [21], could
be used as new anti-inflammatory agents. Four drug candidates from novel
bioactive sponge [22] can be used for treatment of not only
inflammation but also cancer. Avarol is a marine sesquiterpenoid
hydroquinone from the sponge with anti-inflammatory and antipsoriatic
properties [23], it inhibits several key biomarkers up-regulated in
the inflammatory response of psoriatic skin.
As bioactive molecules with the anti-inflammatory activity,
microalgae-derived Oxylipins have the therapeutic potential in
inflammatory diseases [24], could act as agonist of peroxisome
proliferator-activated receptor gamma (PPAR-γ) and consequently inhibit
nuclear factor-kappaB (NFκB) signaling pathway activation, thus lowering
the production of inflammatory markers. The marine compound didemnin B
decreases the activity of the cell types implicated in liver
inflammation and fibrosis in vitro [25]. Other MNPs with
anti-inflammatory effects include the extract of the marine sponge A.
caissara [26], the sulfated galactan of the red marine alga Gelidium
crinale [27], and the first marine invertebrate lectin, that is,
holothuria grisea agglutinin [15]. But whether they have also
antiviral effects, particularly anti-infection of SARS-CoV-2, it needs
both experiments and trials to confirm their potentials.