Lauric acid vs. SARS-CoV-2
In this milieu, it is imperative to assess the suitability of coconut
oil-derived lauric acid in treating COVID 19 caused by SARS-CoV-2. The
potential positives for this proposition are SARS-CoV-2 is an enveloped
virus with characteristic lipid membrane having S-glycoproteins (spike
proteins) over its surface. The membrane disrupting role of lauric acid
or its derivatives in the presence of SARS-CoV-2 is yet to be
investigated. Considering the significance of early viral infection
phase, wherein the virus encoded S-proteins effectively binds the human
receptor protein angiotensin converter enzyme 2(hACE2), any disruption
of viral membrane lipids could be detrimental to the viral infection
process and thus could prevent the entry of virus into human cells. In
this context, development of coconut oil based nasal spray either alone
or in combination with other plant-derived essential oils, wherein the
spray composition with anti-microbial, anti-inflammatory and
decongestant attributes shows the great potential (Carolyn et al. 2012;
Willimann 2018). Fatty acid molecules, preferably lauric acid and capric
acid (both of which accounts for >60% of total fatty acids
composition in coconut oil) have been developed into pharmaceutical
formulations as mouth and throat rinse, nose and throat spray or nasal
drops suitable for the treatment of respiratory syncytial virus (RSV).
The efficacy of these virucidal formulations in decreasing the nasal
viral load was demonstrated in mouse models without any off-target
effects (Wyde et al., 2003). Thus, these instances highlight that
development of lauric acid-based novel prophylactic or therapeutic
measures would be of value to block the respiratory infections such as
COVID-19 (Fig.1 ).
[Insert Fig. 1 here ]
Lauric acid as a food supplement was demonstrated to show no signs of
toxicity on biochemical, histopathological profiles of animal models
even at the dosage of 2,000 mg/kg body weight (Khan et al., 2020).
Hence, considering the safety profile of lauric acid and coconut oil
they can be recommended for satisfactory antiviral therapeutic purposes.
It is further corroborated by the development of a proprietary antiviral
formulation based on a short chain fatty acid (SCFA) (caprylic acid),
ViraSAL. It’s efficacy in treating the enveloped viruses such as
Epstein-Barr, measles, herpes simplex, Zika and orf parapoxvirus,
together with Ebola, Lassa, vesicular stomatitis and SARS-CoV-1
pseudoviruses were proven in vitro and in vivo studies
(Fletcher et al., 2020). These investigations further underscore the
importance of SCFAs and MCFAs in the treatment of enveloped viruses due
to its surfactant activity on the virus envelopes. Although monolaurin
is widely available and generally recognized as safe (GRAS) by US-FDA,
the chemical synthesis of coconut lauric acid-based monosaccharide
esters and their anti-microbial characteristics are encouraging. These
monosaccharide lauric acid esters are biodegradable, non-toxic and have
wide medical applications yet antiviral properties are not proven
(Mutmainah et al., 2019). Sodium lauryl sulfate (SLS) – a tensoactive
agent which has detergent properties, is made from lauric acid. The
broad spectrum surfactant activity of SLS has been instrumental in
inactivating the human and animal infecting viruses such as human
immunodeficiency virus (HIV), human papillomavirus (HPV) and herpes
simplex virus (HSV) (Piret et al., 2002) and in demonstrating
microbiocidal activities against the viruses infecting small ruminants
(de Souza 2019). A functional monoglyceride (MAG) has been developed by
esterifying lauric acid and its anti-microbial activity was demonstrated
while using it as a food preservative (Luna et al., 2020).
Furthermore, investigations have shown that monolaurin has
anti-inflammatory effects in rhesus monkey models in response to HIV-1
and SIV infections (Li et al., 2007). Monolaurin suppresses inflammatory
immune responses including the repression of IL-6 (Interleukin -6)
production. Zhang et al (2017) has attributed this effect to the
disrupted lipid dynamics in the T-lymphocytes. The effect of monolaurin
in lowering the levels of IL-6 in COVID-19 patients opens a new avenue
for the designing of novel therapeutics to block SARS-CoV-2 since it has
been demonstrated that production of pro-inflammatory cytokines such as
IL-6 leads to extreme inflammation of bodily parts resulting in acute
respiratory distress syndrome (ARDS) associated with the disease (Liu et
al., 2019). Inhalation of virgin coconut oil (VCO) reduces the
inflammatory responses and relieves asthma related symptoms in rabbit
models of allergic asthma (Kamalaldin et al., 2017) further
substantiating the therapeutic potential of coconut oil. Nevertheless,
prophylactic application of VCO did not evince any relief for allergic
asthma (Kamalaldin et al., 2017).