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Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
5
International Journal of Current Research in
Medical Sciences
ISSN: 2454-5716
(A Peer Reviewed, Indexed and Open Access Journal)
www.ijcrims.com
Review Article Volume 10, Issue 6 -2024
Garlic: a potential traditional herbal medicine to combat
COVID-19
Ankita Pal, Fatema Calcuttawala*
Department of Microbiology, Sister Nivedita University, Kolkata 700156, India
*Corresponding author:
Email: fatema.c@snuniv.ac.in
Phone number: +91-9748518675
Abstract
From ancient times, medicinal plants and their products have been used as a remedy, to eradicate and reduce the
effects and risks of various diseases. Garlic (Allium sativum) is a herbaceous plant that is used as a traditional
medicine to ameliorate a lot of diseases. Garlic is a reservoir of organo-sulfur compounds such as alliin, allicin,
ajoenes, vinyldithiins, and flavonoids such as quercetin. It has been reported to exhibit various biological properties
which include anticarcinogenic, antioxidant, anticoagulant, antidiabetic, anti-atherosclerotic, antibacterial, antifungal,
antiviral, and antihypertensive activities. From studies, it has been found that garlic also possesses immune-
modulatory effects which increase T-lymphocytes, Natural Killer cells, and macrophages. So, it is used as an
immunity booster. Garlic shows some side effects when it is not taken in the correct dose. Therefore, it should be used
properly for treatment of any disease. Recent studies have shown that garlic is beneficial in the treatment of COVID-
19. This review examines the composition, biological properties, and inhibitory effect on COVID-19 directly via
interaction with the viral proteins and indirectly through interaction with the host immune system, adverse effects,
and therapeutic dose of garlic.
Keywords: Antioxidant, antiviral, COVID-19, garlic, immune system
1. Introduction
The pandemic of coronavirus disease 19
(COVID-19) caused by the severe acute
respiratory syndrome coronavirus 2 (SARS-CoV-
2) has resulted in scientists all over the world
carrying out research for the mitigation and
eradication of the disease. They are actively
engaged in the discovery of vaccines, medicines,
and other ways of treatment to reduce the lethal
effects of this virus, as it is causing immense
damage to humanity as well as animals.
COVID-19 is a zoonotic disease which mainly
affects the lungs. The Angiotensin Converting
Enzyme (ACE2 receptor) present in the lungs
serves as the binding site for the entry of
coronavirus into the body. SARS-CoV-2 is an
RNA virus that belongs to the Coronaviridae
family (Chen D et al., 2020). This virus has an
DOI: http://dx.doi.org/10.22192/ijcrms.2024.10.06.002
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
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envelope with some spike on its surface. These
spikes are composed of glycoproteins. The spikes
proteins are responsible for viral attachment and
transmission of the viral genome into our body.
These spike proteins mutate at a very fast rate. In
comparison to the other RNA viruses, coronavirus
has a larger genome (Fauquet C and Fargette D,
2005).Upon infection with SARS-CoV-2,
COVID-19 patients show some symptoms, the
most common ones being dry cough, respiratory
problems, and loss of appetite (Chen D et al.,
2020; Wang Y et al., 2020). Sometimes the
patients are asymptomatic too. Studies have
shown that SARS-CoV-2 is more infectious than
SARS-CoV-1 and MERS (Wang Y et al., 2020).
In order to combat COVID-19, garlic, a
traditional medicine could be used as it boosts our
immune system and is not so harmful.
Garlic (Allium sativum) is a species of the onion
genus, allium. It has historical importance as it is
used as a curative therapy for numerous diseases
and diet conditions (Bayan L et al., 2014). It is
found to harbor antioxidant, anticarcinogenic,
antibacterial, antifungal, and many other
antimicrobial properties. Apart from being used as
a medicine, it has other uses such as preservatives
for foods and as a flavoring agent (El-Saber
Batiha et al., 2020). It assists in boosting the
immune system as well as decreases the chances
of getting diabetes and cardiovascular diseases
(Rahman K, 2001). Aged garlic extract (AGE)
(kyolic) was reported to decrease cholesterol
levels and thus lower the risk of atherosclerosis
(El-Saber Batiha et al., 2020). It was also found to
decrease the oxidation of lipids and was reported
to lower the blood pressure. Garlic exhibits
antiviral activity against Coxsackie Virus species,
Herpes Simplex Virus types 1 and 2, Influenza B
virus, Vesicular Stomatitis Virus, Human
Immunodeficiency Virus type 1, and human
rhinovirus type 2 (Rahman K, 2001). Some
studies found that it helps in reducing the ACE2
receptors, which are the main receptors for
binding to the COVID-19 virus. Hence, garlic
could be used to treat various diseases, from
whooping cough to cardiovascular diseases. Even
it is used in treating Alzheimer's patients. Garlic
contains organosulphur-rich compounds, which
are biologically important. Allicin is the most
important compound that gives garlic a
characteristic smell and taste and is primarily
responsible for its antibacterial activity
(Chakraborty D and Majumdar A, 2020).
Quercetin, a flavonoids compound that is also
present is used for medications in combination
with vitamins, especially vitamin C. From
previous studies it has been found that quercetin
is an antiviral agent that performs many functions
such as inhibition of virus entry, interfering with
DNA and RNA polymerases, and inhibition of
proteases and other enzymes (Colunga Biancatelli
RML et al., 2020). There are other compounds
that are equally important and effective against
various diseases. Garlic is used against COVID-
19 effectively because it suppresses the Main
protease (Mpro) enzyme which is responsible for
the activation of the virus. The virus is viable,
when it enters the body, due to the presence of the
M protease enzyme which plays an important role
in viral replication and the production of some
functional proteins. Studies have shown that
allicin, other organosulphur compounds, and
flavonoids have a high potential against viral
activity. It was found that quercetin blocks the
protease at the initial attachment stage of the virus
to inhibit viral action. The main reason behind
the inhibition of the virus is the formation of
hydrogen bonds between the enzyme protease and
garlic compounds (Liu X and Wang XJ, 2020).
Entry of virus into the cell affects the immune
system, so the virus is inhibited not only by the
interaction of garlic compounds with viral
enzymes but garlic compounds also boost the
immune system.
Bioactive compounds present in garlic exhibit
immunomodulatory, antioxidant, antimicrobial,
and anti-inflammatory activities which increase
the activity of lymphocytes, natural killer cells,
and macrophages thereby modulating the immune
system.
The immune system under COVID-19 stress
involves a decreased number of T cells, Natural
killer cells, and macrophages. However, the
production of leptin and some anti-inflammatory
cytokines such as tumor necrosis factor-alpha
(TNF-α), interleukin-1 (IL-1), interleukin-2 (IL-
2), and interleukin-6 (IL-6) increases (Qin C et
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
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al., 2020). T cells are vital for the immune system.
There are two types of T cells which are Helper T
cells and Cytotoxic T cells. Both the cells protect
the body from foreign particles and diseases.
Helper T cells help other cells of the immune
system whereas cytotoxic T cells destroy the
infected cells and tumors. Natural killer cells have
the same activity as the suppressor T cells, but the
only difference lies in their way of killing (Donma
MM and Donma O, 2020).
The loss of appetite is due to the increase in
leptin, which is a hormone (Donma MM and
Donma O, 2020). In this article, we will discuss
the various aspects of garlic including the
composition of garlic, the different activities of
particular compounds present in garlic, the
interaction between the M protease enzyme and
bioactive compounds, how garlic is important for
our body, the effect of garlic on the immune
system during the COVID-19 pandemic and
supplementation dosage of garlic.
2. Composition of garlic
Garlic contains a lot of chemical compounds
mostly which are sulfur-compounds such as
Alliin, Allicin, E-Ajoene, Z-Ajoene, 2-Vinyl-4H-
1,3-dithiin, Diallyl sulfide (DAS), Diallyl
disulfide (DADS), Diallyl trisulfide (DATS),
Allyl methyl sulfide (AMS) (Bayan L et al., 2014;
El-Saber Batiha et al., 2020; Chakraborty D and
Majumdar A, 2020). Constituents of garlic have
the ability to boost immunity and hence can
ameliorate numerous diseases (El-Saber Batiha et
al., 2020). The presence of allinase enzyme in
garlic leads to the conversion of an alliin
compoundto allicin (El-Saber Batiha et al., 2020;
Kaye AD et al., 2000). Allicin is a yellow oily
liquid, which is unstable, hence it could be
decomposed to ajoenes under specific
temperatures. It is degraded to ajoenes ((E)-and
(Z)- 4,5,9-trithiadodeca-1,6,11-triene-9-oxides)
and vinyldithiins (Khubber S et al., 2020).
Table 1. Compounds present in garlic with their structures and functions
Compounds
MolecularFormula
Structure
Functions
Alliin
C6H11NO3S
Anti-oxidant,
Anti-microbial,
Cardioprotective,
Neuroprotective
Allicin
C6H10OS2
Anti-oxidant,
Anti-carcinogenic,
E-Ajoene
C9H14OS3
Antioxidant,
Antithrombotic
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
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Z-Ajoene
C9H14OS3
Antioxidant,
Antithrombotic
2-Vinyl-4H-
1,3dithiin
C6H8S2
Anti-obesity
Diallyl sulfide
C6H10S
Antioxidant,
Anticarcinogenic
Diallyl disulfide
C6H10S2
Anti-neoplastic,
Antifungal
Diallyl trisulfide
C6H10S3
Anti-oxidant,
Anti-fungal,
Antitumor
Allyl methyl
sulfide
C4H8S
Antioxidant,
Anti-inflammatory
Each compound has a particular activity such as
immunomodulatory, anti-inflammatory,
anticancer, antitumor, antidiabetic, anti-
atherosclerotic, and cardioprotective activity
respectively (Khubber S et al., 2020) (Table1).
Allyl mercaptan is the compound responsible for
the odour of garlic and it is formed from the
combination of allicin and cysteine via a complex
compound (El-Saber Batiha et al., 2020; Kaye AD
et al., 2000; Rahman S, 2007). There are many
derived compounds of allicin such as N-acetyl
cysteine (NAC), S- allyl cysteine (SAC), and S-
ally-mercapto cysteine (SAMC) (El-Saber Batiha
et al., 2020) (Fig.1). It was found that SAC
harbors some activities like anti-oxidant, anti-
inflammation, redox regulation, pro energetic
(energizes the cells), antiapoptotic and cell
signaling, whereas SAMC displays anticancer
property, which helps in inhibition of cancer cell
growth (El-Saber Batiha et al., 2020; Zeng Y et
al., 2017). Studies have shown that allicin shows
specific inhibition activity to acetyl CoA
synthetases, hence affecting numerous
biochemical pathways such as lipid biosynthesis,
and RNA synthesis, which inevitably occur in
mammals as well as microorganisms (Rahman
MS, 2007). Experimentally, the antiviral activity
of garlic constituents was found against influenza
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
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viruses. It was found to produce antibodies in the
presence of ajoene, allicin, and allyl methyl
thiosulfate (El-Saber Batiha et al., 2020). Diallyl
trisulfide (DATS) shows antiviral activity by
stimulating Natural killer (NK) cells that kill the
virus-infected cells. Ajoenes exhibit antiviral
activity by fusion of leukocytes and prevention of
adhesive interaction of viral particles to cells (El-
Saber Batiha et al., 2020). Ajoenes have been
reported to stimulate apoptosis in leukemic cells
and also promote peroxide production. Ajoenes
can exhibit anti-obesity function also, it decreases
body weight.
Fig 1. Compounds derived from allicin
Even,1,2-vinyldithiiin shows anti-obesity activity.
Aged garlic extract (AGE)/Aged black garlic
(ABG) is another widely studied compound,
which has many beneficial effects. It is produced
by storing garlic in 15-20% ethanol for a specified
time. In the production of AGE, degradation of
allicin occurs and activities of some newer
compounds increase such as S-allyl cysteine, S-
allyl mercapto cysteine, allixin, N-0- (Ideoxy-D-
fructose-1-yl), L-arginine and selenium which are
more stable than allicin and importantly they
exhibit antioxidant and anti-inflammatory
properties (Bayan L et al., 2014; El-Saber Batiha
et al., 2020). ABG is dark brown colored garlic
with a sweet and sour flavor and has a jelly-like
appearance. It has higher concentrations of
components with free sugar and minerals
compared to fresh raw garlic (FRG). ABG shows
strong antioxidant effects but in comparison to
FRG, it shows lower anti-inflammatory, anti-
coagulation, anti-allergic, and immunomodulatory
functions (Ryu JH and Kang D, 2017). Quercetin
is another effective compound that is also present
in garlic. It is a flavonoid that is found in many
vegetables, leaves, and grains in the form of
glycosides (Khubber S et al., 2020; Wu W et al.,
2015) (Fig.2). It mainly exhibits antiviral,
antioxidant, and anti-inflammatory activities.
During viral infections, this compound helps by
inhibiting polymerases, proteases, reverse
transcriptases, and DNA gyrases and binding to
the viral capsid proteins (Wu W et al., 2015).
c) S-allymercapto
cysteine
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Fig 2. Structure of Quercetin
Other compounds such as Diallyl disulfide
(DADS), and Diallyl trisulfide (DATS) exhibit
similar properties such as anti-carcinogenic
activity, lowering blood pressure (Rahman K,
2001), decrease in serum cholesterol levels (Zeng
Y et al., 2017), reduction in body fat, increase in
appetite (Donma MM and Donma O, 2020) and it
has several other beneficial effects. Garlic extract
(GE) has a lot of potential health advantages.
Gamma-glutamylcysteine is a bioactive
compound that shows anti-hypertensive activity
byinhibiting ACE2. These could protect liver cells
from toxic agents by antioxidant defense
mechanisms. Hepatotoxicity is generally caused
by acetaminophen. GE is also beneficial in
diabetic patients, as it helps in lowering insulin
resistance (Chakraborty D and Majumdar A,
2020). Platelets are thrombocytes and fibrin are
the soluble proteins, which are essential for blood
clotting. Higher amounts of fibrin can lead to a
heart attack. Garlic constituents can decrease the
fibrin formation and also decrease the amount of
fibrin present in blood (Chakraborty D and
Majumdar A, 2020).
3. Effect of Garlic on the immune system
There have been several studies on the effect of
the infection of a virus on the immune system
cells. Those cells that decrease in number include,
regulatory T cells, cytotoxic and helper T cells,
Natural killer (NK) cells, interferon-gamma
(IFN-γ), macrophages, and monocytes, whereas,
pro-inflammatory cytokines such as tumor
necrosis alpha factor (TNF-α), interleukin-1 (IL-
1), interleukin-2 (IL-2), interleukin-6 (IL-6) and
another compound leptin were found to be in the
active state (Qin C et al., 2020; Donma MM and
Donma O, 2020; Wang F et al., 2020) (Fig.3).
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
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Fig 3. Fate of the immune system during COVID-19 infection
Consumption of garlic leads to the stimulation of
Helper T cells and Cytotoxic T cells as well as
Natural Killer cells (Donma MM and Donma O,
2020; Arreola R et al., 2015). On the other hand,
leptin, leptin receptor, peroxisome proliferator-
activated receptor gamma (PPAR-γ), and IL-6
were downregulated (Donma MM and Donma O,
2020) (Fig.4). Hence Garlic counteracts the
effects caused by the virus.
Fig 4. Effects of garlic on the immune system
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
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Leptin is an anorexigenic hormone that signals the
brain “not to eat”, therefore it causes appetite loss.
An experiment was done on some participants
who were allowed to eat salads and garlic bread.
From this, it was found that the participants felt
less hungry after consumption of salads compared
to the garlic bread. So, it can be concluded that
garlic increases the appetite (Donma MM and
Donma O, 2020; Buckland NJ et al., 2013).
Metabolism of leptin is assisted by alpha-
melanocyte-stimulating hormone. Leptin
decreases the appetite (Paudel KR et al.,2022), by
stimulating the proopiomelanocortin (POMC),
and cocaine amphetamine-regulated expression
(CART) and simultaneously decreasing the
agouti-related peptide (AgRP) and neuropeptide
Y expression (NPY) (Buckland NJ et al., 2013)
(Fig.5). The four neurons NPY, POMC, AgRP
and CART are directly connected to the leptin.
NPY and AgRP are considered as an orexigenic
hormone, which increases appetite, whereas
POMC and CART are anorexigenic and decrease
appetite. The downregulation of some immune
cells is brought about by constituents of garlic
such as the decrease in expression of
proinflammatory cytokines is influenced by alliin
(Arreola R et al., 2015). Similarly, other
constituents induce some functions that reduce the
effects of coronavirus on the immune system. The
production of proinflammatory cytokines is also
decreased by aged garlic extract (AGE). An
experiment was done, where AGE was applied to
the hypothalamus which showed a decrease in
leptin (Amor S et al., 2019). The same experiment
when done in the subcutaneous adipose tissue,
causes a decrease in adipose weight and
suppresses the gene expression of peroxisome
proliferator-activated receptor gamma (PPAR-γ)
and Leptin receptor (LepR). Adenosine
monophosphate-activated protein kinase (AMPK)
is stimulated by ABG, which in turn inhibits the
transcriptional activity of PPAR-γ in liver cells
(Sozio MS et al., 2011). The phosphorylation of
acetyl CoA carboxylase is induced by AMPK.
Due to this process, the enzyme gets inactivated
which is needed in the conversion of acetyl CoA
to malonyl CoA. Therefore, the inhibition of this
process inhibits the production of fatty acids.
AGE treatment is also a remedy for
atherosclerosis and type 2 diabetes (Amor S et al.,
2019; Sozio MS et al., 2011). This treatment
could be helpful in treating co-morbid diseases.
So, AGE treatment can be directly or indirectly
beneficial for COVID-19.
Fig 5. Effects of leptin on the immune system and regulation of appetite
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
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4. Interaction of virus and constituents
of garlic
The main reason behind the activation of the virus
is the viral enzymes and proteins, which are
responsible for the nourishment and growth of the
virus. In recent research, the structure of Mpro,
(also called as 3CL protease) a protease enzyme
was observed. This enzyme is the main reason
behind viral replication (Ashraf H et al., 2023)
and the production of functional proteins. This is
the key enzyme, which is responsible for the
translation of the polypeptide (Khubber S et al.,
2020). Mpro is a cysteine protease in which
cysteine and histidine are present in its active
center. This cysteine and histidine present in a
combined form are known as catalytic dyad.
Some catalytic dyad with a third residue, which is
a buried water molecule, also occupies the same
active site (Ullrich S and Nitsche C, 2020). From
studies, it was found that this main protease is
available in both, SARS-CoV-1 as well as SARS-
CoV-2 but with a slight difference in the
structural sequence. Both the viral sequences
show 96% of similarity (Liu X and Wang XJ,
2020; Khubber S et al., 2020; Ullrich S and
Nitsche C, 2020).
In another research, it was found that the
conserved part of the polypeptide is responsible
for the formation of binding pockets (binding
sites) for some drugs such as lopinavir/ritonavir.
The conserved amino acids include Thr24, Asn28,
and Asn119, which happen to be in active regions
of the binding pocket (Liu X and Wang XJ, 2020;
Zhang L et al., 2020). The conserved amino acids
are not interrupted by any non-conserved amino
acids in the binding pocket region rather they are
very far from the conserved regions. Through
computational mode, the position of amino
acids was easily located. When molecular
docking was done using lopinavir/ritonavir to
SARS-CoV2, it was observed that Mpro showed
high binding affinity to the binding pocket site,
similar to the previous report found for SARS-
CoV Mpro.
A prediction was made based on studies, that the
amino acids Thr24, Thr26, and Asn119 are the
main residues that form hydrogen bonds with the
lopinavir and ritonavir drugs. The residues form
three hydrogen bonds with ritonavir and two
hydrogen bonds with lopinavir, respectively (Liu
X and Wang XJ, 2020; Khubber S et al., 2020).
Based on studies, it can be concluded that the
formation of hydrogen bonds between the drug
and the Mpro would prevent/hinder the function
of SARS-CoV2. If the predicted drugs showed
more hydrogen bonds with SARS-CoV-2 Mpro
than lopinavir/ritonavir, the higher would be their
mutation tolerance than lopinavir/ritonavir (Liu X
and Wang XJ, 2020).
Synthetic drugs are usually effective against the
pathogens, but there are some natural drugs that
contain some phytochemicals that have inhibitory
effects against pathogens. There are many plant
products but garlic is one of them, whose
constituents showed inhibition against
Coronavirus. In a silico experiment, it was
observed that seven organosulfur compounds of
alliin were taken into account to inhibit the
functions of Mpro of SARS-CoV2. The seven
derived compounds of alliin that take part in this
experiment are S-(allyl/ methyl/ethyl/propyl)-
cysteine, S-propyl L-cysteine, and S-
allymercapto. Cysteine forms hydrogen bonds
with protease enzymes to prevent it from
functioning. Computational analysis has
considered these compounds have antiviral
potential to prevent COVID-19. Earlier, it was
seen that Quercetin had prevented protease in
SARS-CoV-1 during multiplication in host cells
by blocking the viral attachment stage (Khubber
S et al., 2020). A natural compound and a
different form of Quercetin, Quercetin-3-β-
galactoside was observed as a new class inhibitor
against SARS- CoV 3CLpro through molecular
docking as well as many assays such as
Fluorescence resonance energy transfer (FRET)
assay (Chen L et al., 2006). We learned about so
many constituents present in garlic which are
effective against COVID-19 as well as other
diseases. But, this herbal drug or the constituents
of garlic are only beneficial and will act
effectively, when it is given at the correct
amount. Otherwise, garlic could be toxic.
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
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5. Side effects and Toxicity
Generally, the dosage comprises of 4g (one or two
cloves) of raw garlic per day, one 300-mg dried
garlic powder tablet two to three times per day, or
7.2 g of AGE per day for elderly persons
(Tattelman E, 2005). In an experiment, female
and male rats were supplemented with garlic at
300 and 600 mg for 21 days, and was reported
that garlic caused delays in growth and affected
the biological and histological parameters
(Mikaili P et al., 2013). A study on garlic showed
that its application results in mild inflammation,
but it can cause skin reactions and deep chemical
burns if applied under pressure bandage or poor
wound or near secondary infection (Mikaili P et
al., 2013). Garlic can be used in synergistic
therapy to invade toxicity, and there is an
elevation of antioxidant enzymes as well as
antihypertensive and cardioprotective activities
(El-Saber Batiha et al., 2020). Many trials were
performed, experiments were done and some side
effects such as insomnia, vomiting, dizziness,
headache, nausea, heartburn, diarrhea, bloating,
sweating, offensive body odor, and mild
orthostatic hypotension were observed (El-Saber
Batiha et al., 2020).
Garlic does not seem to affect drug metabolism,
but recent reports on trials done on healthy
participants showed inconsistent results. Garlic
has an effect on the pharmacokinetics of protease
inhibitors, as well as anticoagulants due to its
antithrombotic properties (Rahman K and Lowe
GM, 2006). The consumption of garlic has an ill
effect, causing a decrease in coagulation of
bleeding so it is normally advised that a patient
undergoing surgery should not consume garlic at
high doses 7 to 10 days earlier (Mikaili P et al.,
2013). According to studies, it was reported that
low consumption of garlic is innocuous, whereas
the medicinal doses can cause mild
gastrointestinal disorders, and high doses cause
liver damage (Ried K and Fakler P, 2014;
Almogren A et al., 2013).
6. Discussion
This review mainly focuses on the constituents of
garlic and their functions in treating diseases,
especially COVID-19. From ancient times it has
been popularly recognized as a traditional
medicine for its therapeutic functions. This herbal
spice has gained renewed interest due to its
therapeutic effects in the prevention and treatment
of various diseases. Recent studies and
experiments on this herbal spice have unveiled a
wide range of applications. Garlic contains sulfur-
rich compounds including alliin, allicin, ajoenes,
vinyldithiins, and sulfides which are considered as
main constituents (He Z et al., 2023). These
extracted compounds harbor many
pharmacological activities such as antiviral, anti-
inflammatory, anticarcinogenic, antioxidant,
antidiabetic, renoprotective, anti-atherosclerotic,
antibacterial, antifungal, antiprotozoal, and
antihypertensive activities (Diantini A et al.,
2023). Because of these effects, it helps in the
prevention and treatment of various respiratory
diseases (Giang T et al., 2023). Every compound
present in garlic contributes to its anti-
inflammatory effects (Diantini A et al., 2023).
Each component of garlic possesses antioxidant
properties.
So far, we have seen that the effective way to
fight against COVID-19 is to boost our immune
system. Studies emphasizing on
immunomodulatory effects of garlic have reported
anincrease in the activity and number of cytokine
suppressors, lymphocytes, natural killer cells, and
macrophages and a decrease in leptin could boost
the immune system. Therefore, it could be used as
an alternative and effective way to fight against
COVID-19. In COVID-19, mainly appetite
decreases, to counteract that garlic could be used
as it decreases the leptin hormone content (Paudel
KR et al.,2022). This review also provides
valuable information on Mpro and how the
bioactive compounds of garlic bind to Mpro and
inhibit its activity (Khubber S et al., 2020; Ashraf
H et al., 2023). Mpro is the main protease
enzyme, which is responsible for viral replication,
viral protein production, and attachment to the
host. This herbal spice could be used as an
effective remedy, both synergistically as well as
individually. Garlic has some side effects also if
administered in high doses. Therefore, it is
advised to use it properly for any medication or
treatment of disease. Hence garlic has the
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
15
potential to ameliorate many diseases including
COVID-19.
Financial support & sponsorship: None
Conflicts of Interest: None
References
Almogren A, Shakoor Z, Adam MH. Garlic and
onion sensitization among Saudi patients
screened for food allergy: a hospital based
study. 2013. Afr Health Sci. 13(3):689-
693.
Amor, S., González-Hedström, D., Martín-Carro,
B., Inarejos-García, A. M., Almodóvar, P.,
Prodanov, M., García-Villalón, A. L., and
Granado, M. 2019.Beneficial Effects of an
Aged Black Garlic Extract in the
Metabolic and Vascular Alterations
Induced by a High Fat/Sucrose Diet in
Male Rats. Nutrients. 11(1):153
Arreola, R., Quintero-Fabián, S., López-Roa, R.
I., Flores-Gutiérrez, E. O., Reyes-Grajeda,
J. P., Carrera-Quintanar, L., and Ortuño-
Sahagún, D. 2015.Immunomodulation and
anti-inflammatory effects of garlic
compounds. J Immunol Res. 2015:401630.
Ashraf H, Dilshad E, Afsar T, Almajwal A,
Shafique H, and Razak S. 2023. Molecular
Screening of Bioactive Compounds of
Garlic for Therapeutic Effects against
COVID-19. Biomedicines. 11(2):643.
Bayan, L., Koulivand, P. H., and Gorji, A. 2014.
Garlic: a review of potential therapeutic
effects. Avicenna J Phytomed. 4(1):1-14.
Buckland, N. J., Finlayson, G., and Hetherington,
M. M. 2013.Slimming starters. Intake of a
diet-congruent food reduces meal intake in
active dieters. Appetite. 71:430-437.
Chakraborty, D., and Majumder, A. 2020.Garlic
(Lahsun) –An Immunity Booster Against
SARS-CoV-2. BioResToday.2(8):755-
757.
Chen, G., Wu, D., Guo, W., Cao, Y., Huang, D.,
Wang, H., Wang, T., Zhang, X., Chen, H.,
Yu, H., Zhang, X., Zhang, M., Wu, S.,
Song, J., Chen, T., Han, M., Li, S., Luo,
X., Zhao, J., and Ning, Q. 2020.Clinical
and immunological features of severe and
moderate coronavirus disease 2019. J Clin
Invest. 130(5):2620-2629
Chen, L., Li, J., Luo, C., Liu, H., Xu, W., Chen,
G., Liew, O. W., Zhu, W., Puah, C. M.,
Shen, X., and Jiang, H. 2006. Binding
interaction of quercetin-3-beta-galactoside
and its synthetic derivatives with SARS-
CoV 3CL (pro): structure-activity
relationship studies reveal salient
pharmacophore features. Bioorg Med
Chem. 14(24):8295-8306.
Colunga Biancatelli, R. M. L., Berrill, M.,
Catravas, J. D., and Marik, P. E.
2020.Quercetin and Vitamin C: An
Experimental, Synergistic Therapy for the
Prevention and Treatment of SARS-CoV-
2 Related Disease (COVID-19). Front
Immunol. 11:1451
Diantini, A., Febriyanti, R. M., and Levita, J.
2023. Efficacy and Safety of Add-On
Plant-Based Drugs for COVID-19
Patients: A Review of the Randomized
Control Trials. Infect Drug Resist.
16:3879-3891
Donma, M. M., and Donma, O. 2020. The effects
of allium sativum on immunity within the
scope of COVID-19 infection. Med
Hypotheses. 144:109934.
El-Saber Batiha, G., Magdy Beshbishy, A., G
Wasef, L., Elewa, Y. H. A., A Al-Sagan,
A., Abd El-Hack, M. E., Taha, A. E., M
Abd-Elhakim, Y., and Prasad Devkota, H.
2020. Chemical Constituents and
Pharmacological Activities of Garlic
(Allium sativum L.): A Review. Nutrients.
12(3):872.
Fauquet, C. M., and Fargette, D. 2005.
International Committee on Taxonomy of
Viruses and the 3,142 unassigned
species. Virol J. 2:64
Giang, T. V., Hoa, L. N. M., Hien, T. T., Cuong,
Q. D., Cap, N. T., Lam Vuong, N., and
Thach, P. N. 2023. Traditional Vietnamese
Medicine Containing Garlic Extract for
Patients With Non-severe COVID-19: A
Phase-II, Double-Blind, Randomized
Controlled Trial. Cureus. 15(7):e42484
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
16
He, Z., Yuan, J., Zhang, Y., Li, R., Mo, M.,
Wang, Y., and Ti, H. 2023.Recent
advances towards natural plants as
potential inhibitors of SARS-Cov-2
targets. Pharm Biol. 61(1):1186-1210.
Kaye, A. D., De Witt, B. J., Anwar, M., Smith, D.
E., Feng, C. J., Kadowitz, P. J., and
Nossaman, B. D. 2000. Analysis of
responses of garlic derivatives in the
pulmonary vascular bed of the rat. J Appl
Physiol 89(1):353-358.
Khubber, S., Hashemifesharaki, R., Mohammadi,
M., and Gharibzahedi, S. M. T. 2020.
Garlic (Allium sativum L.): a potential
unique therapeutic food rich in
organosulfur and flavonoid compounds to
fight with COVID-19. Nutr J. 19(1):124.
Liu, X., and Wang, X. J. 2020. Potential inhibitors
against 2019-nCoV coronavirus M
protease from clinically approved
medicines. J Genet Genomics. 47(2):119-
121
Mikaili, P., Maadirad, S., Moloudizargari, M.,
Aghajanshakeri, S., and Sarahroodi, S.
2013. Therapeutic uses and
pharmacological properties of garlic,
shallot, and their biologically active
compounds. Iran J Basic Med Sci.
16(10):1031-1048.
Paudel, K. R., Patel, V., Vishwas, S., Gupta, S.,
Sharma, S., Chan, Y., Jha, N. K., Shrestha,
J., Imran, M., Panth, N., Shukla, S. D.,
Jha, S. K., Devkota, H. P., Warkiani, M.
E., Singh, S. K., Ali, M. K., Gupta, G.,
Chellappan, D. K., Hansbro, P. M., and
Dua, K. 2022.Nutraceuticals and COVID-
19: A mechanistic approach toward
attenuating the disease complications. J
Food Biochem. 46(12):e14445.
Qin, C., Zhou, L., Hu, Z., Zhang, S., Yang, S.,
Tao, Y., Xie, C., Ma, K., Shang, K.,
Wang, W., and Tian, D. S. 2020.
Dysregulation of Immune Response in
PatientsWith Coronavirus 2019 (COVID-
19) in Wuhan, China. Clin Infect Dis.
71(15):762-768.
Rahman, K., and Lowe, G. M. 2006.Garlic and
cardiovascular disease: a critical review. J
Nutr. 136(3 Suppl):736S-740S.
Rahman K. 2001.Historical perspective on garlic
and cardiovascular disease. J Nutr.
131(3s):977S-9S.
Rahman, M. S. 2007. Allicin and Other
Functional Active Components in Garlic:
Health Benefits and Bioavailability.
International J. Food Properties 10 (2):
245–68.
Ried, K., and Fakler, P. 2014.Potential of garlic
(Allium sativum) in lowering high blood
pressure: mechanisms of action and
clinical relevance. Integr Blood Press
Control. 7:71-82.
Ryu, J. H., and Kang, D. 2017.Physicochemical
Properties, Biological Activity, Health
Benefits, and General Limitations of Aged
Black Garlic: A Review. Molecules.
22(6):919.
Sozio, M. S., Lu, C., Zeng, Y., Liangpunsakul, S.,
and Crabb, D. W. 2011.Activated AMPK
inhibits PPAR-{alpha} and PPAR-
{gamma} transcriptional activity in
hepatoma cells. Am J Physiol Gastrointest
Liver Physiol. 301(4):G739-G747.
Tattelman E. 2005. Health effects of garlic. Am
Fam Physician. 72(1):103-106.
Ullrich, S., and Nitsche, C. 2020. The SARS-
CoV-2 main protease as drug
target. Bioorg Med Chem Lett.
30(17):127377
Wang, Y., Wang, Y., Chen, Y., and Qin, Q.
2020.Unique epidemiological and clinical
features of the emerging 2019 novel
coronavirus pneumonia (COVID-19)
implicate special control measures. J Med
Virol. 92(6):568-576.
Wang, F., Nie, J., Wang, H., Zhao, Q., Xiong, Y.,
Deng, L., Song, S., Ma, Z., Mo, P., and
Zhang, Y. 2020.Characteristics of
Peripheral Lymphocyte Subset Alteration
in COVID-19 Pneumonia. J Infect Dis.
221(11):1762-1769.
Wu, W., Li, R., Li, X., He, J., Jiang, S., Liu, S.,
and Yang, J. 2015.Quercetin as an
Antiviral Agent Inhibits Influenza A Virus
(IAV) Entry. Viruses. 8(1):6.
Zeng, Y., Li, Y., Yang, J., Pu, X., Du, J., Yang,
X., Yang, T., and Yang, S.
2017.Therapeutic Role of Functional
Components in Alliums for Preventive
Int. J. Curr. Res. Med. Sci. (2024). 10(6): 5-17
17
Chronic Disease in Human Being. Evid
Based Complement Alternat Med.
2017:9402849.
Zhang, L., Lin, D., Sun, X., Curth, U., Drosten,
C., Sauerhering, L., Becker, S., Rox, K.,
and Hilgenfeld, R. 2020. Crystal structure
of SARS-CoV-2 main protease provides a
basis for design of improved α-ketoamide
inhibitors. Science. 368(6489):409-412
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DOI: 10.22192/ijcrms.2024.10.06.002
How to cite this article:
Ankita Pal, Fatema Calcuttawala. (2024). Garlic: a potential traditional herbal medicine to combat
COVID-19. Int. J. Curr. Res. Med. Sci. 10(6): 5-17.
DOI: http://dx.doi.org/10.22192/ijcrms.2024.10.06.002