Clove (Syzygium aromaticum): A precious spice

Abstract

Clove (Syzygium aromaticum) is one of the most valuable spices that has been used for centuries as food preservative and for many medicinal purposes. Clove is native of Indonesia but nowadays is cultured in several parts of the world including Brazil in the state of Bahia. This plant represents one of the richest source of phenolic compounds such as eugenol, eugenol acetate and gallic acid and posses great potential for pharmaceutical, cosmetic, food and agricultural applications. This review includes the main studies reporting the biological activities of clove and eugenol. The antioxidant and antimicrobial activity of clove is higher than many fruits, vegetables and other spices and should deserve special attention. A new application of clove as larvicidal agent is an interesting strategy to combat dengue which is a serious health problem in Brazil and other tropical countries. Pharmacokinetics and toxicological studies were also mentioned. The different studies reviewed in this work confirm the traditional use of clove as food preservative and medicinal plant standing out the importance of this plant for different applications.

Full text

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Document heading doi:10.1016/S2221-1691(14)60215-X 襃 2014 by the Asian Pacific Journal of Tropical Biomedicine. All rights reserved.
Clove (Syzygium aromaticum): a precious spice
Diego Francisco Cortés-Rojas*, Claudia Regina Fernandes de Souza, Wanderley Pereira Oliveira
Laboratory of R&D on Pharmaceutical Processes–LAPROFAR-Faculdade de Ciências Farmacêuticas de Ribeirão Preto/USP, Av. do Café s/n, Bloco Q,
14040-903, Ribeirão Preto, SP, Brazil
Asian Pac J Trop Biomed 2014; 4(2): 90-96
Asian Pacific Journal of Tropical Biomedicine
journal homepage: www.elsevier.com/locate/apjtb
*Corresponding author: Diego Francisco Cortés Rojas, M.Sc., Laboratory of R&D
on Pharmaceutical Processes-LAPROFAR-Faculdade de Ciências Farmacêuticas de
Ribeirão Preto/USP, Av. do Café s/n, Bloco Q, 14040-903, Ribeirão Preto, SP, Brazil.
E-mail: wpoliv@fcfrp.usp.br
Foundation Project: Supported by the São Paulo Research Foundation-FAPESP-
Brazil (Grant No. 2012/09890-6).
1. Introduction
Spices as clove, oregano, mint, thyme and cinnamon,
have been employed for centuries as food preservatives
and as medicinal plants mainly due to its antioxidant and
antimicrobial activities. Nowadays, many reports confirm
the antibacterial, antifungal, antiviral and anticarcinogenic
properties of spice plants. Clove in particular has attracted
the attention due to the potent antioxidant and antimicrobial
activities standing out among the other spices[1].
Syzygium aromaticum (S. aromaticum) (synonym: Eugenia
cariophylata) commonly known as clove, is an median size
tree (8-12 m) from the Mirtaceae family native from the
Maluku islands in east Indonesia. For centuries the trade of
clove and the search of this valuable spice stimulated the
economic development of this Asiatic region[2].
The clove tree is frequently cultivated in coastal areas
at maximum altitudes of 200 m above the sea level. The
production of flower buds, which is the commercialized part
of this tree, starts after 4 years of plantation. Flower buds
are collected in the maturation phase before flowering. The
collection could be done manually or chemically-mediated
PEE R REVIEW ABS TR ACT
KEYWORDS
Spice, Clove, Aromatic plant, Volatile, Antioxidant, Dengue fever, Larvicidal
Clove (Syzygium aromaticum) is one of the most valuable spices that has been used for centuries
as food preservative and for many medicinal purposes. Clove is native of Indonesia but nowadays
is cultured in several parts of the world including Brazil in the state of Bahia. This plant
represents one of the richest source of phenolic compounds such as eugenol, eugenol acetate
and gallic acid and posses great potential for pharmaceutical, cosmetic, food and agricultural
applications. This review includes the main studies reporting the biological activities of clove and
eugenol. The antioxidant and antimicrobial activity of clove is higher than many fruits, vegetables
and other spices and should deserve special attention. A new application of clove as larvicidal
agent is an interesting strategy to combat dengue which is a serious health problem in Brazil and
other tropical countries. Pharmacokinetics and toxicological studies were also mentioned. The
different studies reviewed in this work confirm the traditional use of clove as food preservative
and medicinal plant standing out the importance of this plant for different applications.
Contents lists available at ScienceDirect
Peer reviewer
Dr. Marcos José Salvador, Associated
Professor, Pharmacy Cource,
Department of Plant Biology, Institute
of Biology, State University of
Campinas (UNICAMP).
Tel: 055-19-35216167
E-mail: marcosjs@unicamp.br
Comments
In the review, the authors demonstrated
the main studies reporting the biological
activities of clove (S. aromaticum) and
eugenol. Based on the information
presented, it could be concluded that
clove represents a very interesting
plant with an enormous potential as
food preservative and as a rich source
of antioxidant compounds.
Details on Page 94
Article history:
Received 26 Oct 2013
Received in revised form 4 Nov, 2nd revised form 14 Nov, 3rd revised form 23 Nov 2013
Accepted 22 Dec 2013
Available online 28 Feb 2014

Diego Francisco Cortés-Rojas et al./Asian Pac J Trop Biomed 2014; 4(2): 90-96 91
using a natural phytohormone which liberates ethylene in
the vegetal tissue, producing precocious maturation[3].
Nowadays, the larger producer countries of clove are
Indonesia, India, Malaysia, Sri Lanka, Madagascar and
Tanzania specially the Zanzibar island[2]. In Brazil, clove
is cultured in the northeast region, in the state of Bahia in
the regions of Valença, Ituberá, Taperoá, Camamu and Nilo
Peçanha, where approximately 8 000 hectares are cultivated,
producing near 2 500 tons per year[4-5].
2. Chemical compounds isolated from clove
Clove represents one of the major vegetal sources of
phenolic compounds as flavonoids, hidroxibenzoic acids,
hidroxicinamic acids and hidroxiphenyl propens. Eugenol
is the main bioactive compound of clove, which is found in
concentrations ranging from 9 381.70 to 14 650.00 mg per 100 g
of fresh plant material[6].
With regard to the phenolic acids, gallic acid is the
compound found in higher concentration (783.50 mg/100
g fresh weight). However, other gallic acid derivates as
hidrolizable tannins are present in higher concentrations
(2 375.8 mg/100 g)[1]. Other phenolic acids found in clove are
the caffeic, ferulic, elagic and salicylic acids. Flavonoids
as kaempferol, quercetin and its derivates (glycosilated) are
also found in clove in lower concentrations.
Concentrations up to 18% of essential oil can be found
in the clove flower buds. Roughly, 89% of the clove
essential oil is eugenol and 5% to 15% is eugenol acetate
and β-cariofileno[7]. Another important compound found
in the essential oil of clove in concentrations up to 2.1%
is α-humulen. Other volatile compounds present in lower
concentrations in clove essential oil are β-pinene, limonene,
farnesol, benzaldehyde, 2-heptanone and ethyl hexanoate.
3. Biological activities
Clove is an important medicinal plant due to the wide
range of pharmacological effects consolidated from
traditional use for centuries and reported in literature. A
review of several scientific reports of the most important
biological activities of clove and eugenol is presented in the
following paragraphs.
3.1. Antioxidant activity
Recently, the United States Department of Agriculture in
collaboration with Universities and private companies create
a database with the polyphenol content and antioxidant
activity of different kind of foods. Based on this database,
Pérez-Jiménez et al. classified the 100 richest dietary sources
of polyphenols[8]. Results indicate that the spice plants are
the kind of food with higher polyphenol content followed by
fruits, seeds and vegetables. Among spices, clove showed the
higher content of polyphenols and antioxidant compounds.
In another work published by Shan et al.[1], the main
phenolic compounds in 26 spices were identified and
quantified by high performance liquid chromatography,
followed by the in vitro antioxidant activity analysis by the
ABTS method. Results showed the high correlation between
the polyphenols content and the antioxidant activity. Clove
(buds) was the spice presenting higher antioxidant activity
and polyphenol content, (168.660依0.024) tetraethylammonium
chloride (mmol of Trolox/100g dried weight) and (14.380依
0.006) g of gallic acid (equivalents/100g of dried weight)
respectively. The major types of phenolic compounds
found were phenolic acids (gallic acid), flavonol glucosides,
phenolic volatile oils (eugenol, acetyl eugenol) and tannins.
It was highlighted the huge potential of clove as radical
scavenger and as a commercial source of polyphenols.
The antioxidant activity of clove and caraway were
screened using various in vitro models, such as b-carotene-
linoleate, ferric thiocyanate, 1,1-diphenyl-2-picryl hydroxyl
(DPPH) radical, hydroxyl radical and reducing power model
systems concluding that the antioxidant activity of clove
and caraway is comparable with butylated hydroxytoluene
(BHT), a synthetic compound commonly employed as food
preservative Bamdad et al[9]. According to Gülçin et al.[10],
the antioxidant activity of clove oil compared with synthetic
antioxidants measured as the scavenging of the DPPH radical
decreased in the following order: clove oil>BHT>alfa-
tocopherol>butylated hydroxyanisole>Trolox.
The antioxidant activity of aqueous extracts of clove
has been tested by different in vitro methods as 2,2-
diphenyl-1-picrylhydrazyl (DPP H ); 2,2’-azino-bis
(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), oxigen
radical absorbance capacity, ferric reducing antioxidant
power, xanthine oxidase and 2-deoxiguanosine. Clove and
plants as pine, cinnamon, and mate proved its enormous
potential as food preservative among the other 30 plants
analyzed[11].
Ethanol and aqueous extracts of clove and lavender at
concentrations of 20, 40 and 60 µg/mL showed inhibitions up
to 95% when tested as metal quelants, superoxide radical
capture and scavenging of the DPPH radical. The powerful
antioxidant activity of both extracts may be attributed to the
strong hydrogen donating ability, metal chelating ability
and scavanging of free radicals, hydrogen peroxide and
superoxide[12].
Gülcin studied the antioxidant activity of eugenol by
several in vitro methods and discusses the structure-activity
relationship[13]. Compared to butylated hydroxyanisole,
BHT, Trolox and α-tocopherol, eugenol presented higher
antioxidant activity in most of the methods tested, DPPH,
AB T S , N,N-dimethyl-p-phenylenediamine, CUPR A C
and ferric reducing assay. It was remarked that plant
polyphenols are multifunctional in the sense that they can
act as reducing agents, hydrogen atom donators, and singlet

Diego Francisco Cortés-Rojas et al./Asian Pac J Trop Biomed 2014; 4(2): 90-96
92
oxygen scavengers. Eugenol allows the donation of an
hydrogen atom and subsequent stabilization of the phenoxil
radical generated forming stable compounds that do not start
or propagate oxidation. The eugenol molecule possesses an
interesting conjugation of the carbon chain with the aromatic
ring which could participate in the stabilization of the
phenoxyl radical by resonance. This chromophoric system
is also present in molecule of resveratrol which is another
important antioxidant. It has been proposed the hypothesis
that eugenol reduces two or more DPPH radicals, despite the
availability of only one hydrogen from a hydroxyl group.
The formation of dimers of eugenol (dehydrodieugenol)
with two phenolic hidroxyl groups originated from eugenyl
intermediate radicals has also been proposed as mechanism
between eugenol and DPPH radicals .
In the same way, S. aromaticum oil and Nigella sativa oil
significant protect male rats exposed to aflatoxins which
caused hepato and nephrotoxicity and oxidative stress.
Regarding to the biochemical parameters, such as alanine
aminotransferase, aspartate aminotransferase, alkaline
phospatase, total billirubin, urea, total protein, cholesterol,
the activity of both oils were comparable with the controls[14].
Antioxidants are important compounds for treatment of
memory deficits caused by oxidative stress[15]. Pretreatment
with clove essential oil decreases the oxidative stress
assessed by malondialdehyde and reduced glutathione levels
in mice’s brain. This study concluded that clove oil could
revert memory and learning deficits caused by scopolamine
in short and long term as a result of the reduction in the
oxidative stress[16]. Memory and learning improvements
of clove oil were observed in scopolamine-treated mice
at doses of 0.025, 0.05, and 0.1 mL/kg when compared with
saline solution control group in an elevated plus maze test.
These works prove the benefits of the employment of clove
as a rich source of antioxidants for the treatment of memory
deficits caused by oxidative stress.
Extracts from clove buds could also be used as food
antioxidants. The shelf-life and frying stability of
encapsulated and un-encapsulated eugenol-rich clove
extracts were tested in soybean oil[17]. Controlled release
of antioxidants could be achieved by encapsulated clove
powder obtained by spray drying using maltodextrin and
arabic gum as wall materials.
3.2. Antimicrobial activity
The antimicrobial activities of clove have been proved
against several bacteria and fungal strains. Sofia et al. tested
the antimicrobial activity of different Indian spice plants
as mint, cinnamon, mustard, ginger, garlic and clove[18].
The only sampled that showed complete bactericidal effect
against all the food-borne pathogens tested Escherichia coli
(E. coli), Staphylococcus aureus and Bacillus cereus was the
aqueous extract of clove at 3%. At the concentration of 1%
clove extract also showed good inhibitory action.
In another work published by Dorman and Deans[19], the
antibacterial activity of black pepper, geranium, nutmeg,
oregano, thyme and clove was tested against 25 strains of
Gram positive and Gram negative bacteria. The oils with the
widest spectrum of activity were thyme, oregano and clove
respectively.
The antibacterial activity of clove, oregano (Origanum
vulgare), bay (Pimenta racemosa) and thyme (Thymus
vulgaris) essential oil was tested against E. coli O157:H7
showing the different grades of inhibition of these essential
oils[20]. Likewise formulations containing eugenol and
carvacrol encapsulated in a non ionic surfactant were tested
against four strains of two important foodborne pathogens, E.
coli O157:H7 and Listeria monocitogenes, results reinforces
the employment of eugenol to inhibit the growth of these
microorganisms in surfaces in contact with food[21].
Rana et al. determined the antifungic activity of clove oil
in different strains and reported this scale of sensibility
Mucor sp.>Microsporum gypseum>Fusarium monoliforme
NCIM 1100>Trichophytum rubrum>Aspergillus sp.>Fusarium
oxysporum MTCC 284[22]. The chromatographic analyses
showed that eugenol was the main compound responsible
for the antifungic activity due to lysis of the spores and
micelles. A similar mechanism of action of membrane
disruption and deformation of macromolecules produced by
eugenol was reported by Devi et al[23].
The activities of clove oil against different dermatophytes
as Microsporum canis (KCTC 6591), Trichophyton
mentagrophytes (KCTC 6077), Trichophyton rubrum (KCCM
60443), Epidermophyton floccosum (KCCM 11667) and
Microsporum gypseum were tested and results indicate a
maximum activity at concentration of 0.2 mg/mL with an
effectiveness of up to 60%[24].
Pure clove oil or mixes with rosemary (Rosmarinus
officinalis spp.) oil were tested against Staphylococcus
epidermidis, Staphylococcus aureus, Bacillus subtilis, E.
coli, Proteus vulgaris, Pseudomonas aeruginosa and results
showed minimum inhibitory concentrations between 0.062%
and 0.500% (v/v) which is promising as antiinfenccious agents
or as food preservative[25].
The anticandidal activity of eugenol and carvacrol was
tested in a vaginal candidiasis model, microbial and
histological techniques were employed to compare the
samples with the controls. The results suggest that eugenol
and carvacrol could be a promising antifungal agent for
treatment and prophylaxis of vaginal candidiasis[26].
In addition to the wide spectrum of activity of eugenol
against bacteria, a study showed that eugenol and
cinnamaldehyde at 2 µg/mL inhibited the growth of 31 strains
of Helicobacter pylori, after 9 h and 12 h of incubation,
respectively, being more potent that amoxicillin and
without developing resistance. The activity and stability
of those compounds was checked at low pH values since
Helicobacter pylori resides in the stomach[27].
Solid lipid nanoparticles containing eugenol were

Diego Francisco Cortés-Rojas et al./Asian Pac J Trop Biomed 2014; 4(2): 90-96 93
prepared employing stearic acid, caprylic triglyceride and
Poloxamer 188 in different concentrations by a modified hot
homogenization ultrasonication method. The particles formed
were characterized by the particle size, polydispersitivity
index, morphology, zeta potential, crystalline state and
encapsulation efficiency. The antifungal activity of solid
lipid nanoparticles was tested in vivo by using a model of
oral candidiasis (Candida albicans) in immunosupressed
rats. The results showed the increase in the therapeutic
effectiveness of eugenol and the modification of the release
when administrated as solid lipid nanoparticles[28].
Beta-cyclodextrin inclusion complexes containing
eugenol and clove bud extracts were tested against two
common foodborne pathogens, Salmonella enterica serovar
Typhimurium LT2 and Listeria innocua[29]. Clove products
have a great potential as food additives since they are very
effective and for being natural products are preferred for
consumers. Moreover, the solubility and the delivery are
improved with the encapsulation process.
3.3. Antinociceptive
The employment of clove as analgesic have been
reported since the 13th century, for toothache, join pain
and antispasmodic, being the eugenol the main compound
responsable for this activity. The mechanism evolved has
been attributed to the activation of calcium and chloride
channels in ganglionar cells[30]. The voltage dependant
effects of eugenol in sodium and calcium channels and
in receptors expressed in the trigeminal ganglio also
contributed to the analgesic effect of clove[31]. Other results
show that the analgesic effect of clove is due to the action as
capsaicin agonist[32]. The peripheral antinociceptive activity
of eugenol was reported by Daniel et al. showing significant
activity at doses of 50, 75 and 100 mg/kg[33].
3.4. Antiviral
The antiviral activity of eugeniin, a compound isolated
from S. aromaticum and from Geum japonicum, was tested
against herpes virus strains being effective at 5 µg/mL, and
it was deducted that one of the major targets of eugeniin is
the viral DNA synthesis by the inhibition of the viral DNA
polymerase [34].
In another study, aqueous extracts of S. aromaticum (L.)
Merr. et Perry and other plants as Geum japonicum Thunb.,
Rhus javanica L., and Terminalia chebula Retzus among
others showed strong antiherpes simplex virus type 1 (HSV-1)
activity when combined with acyclovir. This synergic activity
was stronger in the brain that in the skin and it was also
proved that those combinations were not toxic to mice[35].
3.5. Citotoxicity of eugenol
After several years of intensive research, various
molecular targets for the prevention and treatment of cancer
have been identified. Eugenol was selected as a potential
molecule that can interfere with several cell-signaling
pathways, specifically the nuclear factor kappa B (NF-
KB). This factor is activated by free radicals and results in
the expression of gens that suppress apoptosis and induce
cellular transformation, proliferation, invasion, metastasis
among others[36].
The anti-oxidative, citotoxic and genotoxic effects of
eugenol and borneol were tested as the ability to modulate
resistance against the damaging effects of H2O2 on DNA of
different strains of human cells: malignan HepG2 hepatome
cells, malignan Caco-2 colon cells and non malignan human
VH10 fibroblast. Results showed that eugenol presented a
notable anti-oxidative potential at all the concentrations
tested. It was also evidenced that the citotoxic effects of
eugenol were stronger than those of borneol. With regard to
toxicity, eugenol presented strong genotoxic effects (DNA-
damaging) on human VH10 fibroblast, medium genotoxic
effects on Caco-2 colon cells and non DNA-damaging
effects on HepG2 hepatome cells[37]. Nevertheless the
National Toxicology Program based on several long term
carcinogenicity studies concluded that eugenol was not
carcinogenic to rats[38].
In another study, the eugenol suppressed the growth of the
malign melanoma WM1205Lu of both anchorage-dependent
and anchorage-independent growth, decreases size of
tumors and inhibits melanoma invasion and metastasis
by the inhibition of the two transition factors of the E2F
family[38].
Although there are many reports of the antioxidant
activity of eugenol, at high concentration eugenol could
be prooxidant. The cytotoxicity, reactive oxygen species
(ROS) production, and intracellular glutathione levels in a
human submandibular cell line (HSG cells) of eugenol and
isoeugenol was studied by Atsumi et al[39]. It was found
that in the absence of oxidative stress eugenol acts as an
antioxidant at low concentrations but acts as a prooxidant
at high concentrations. In the presence of oxidative stress
eugenol increased ROS levels at low concentrations (5-10 µmol/
L), but decreased them at high concentrations (500 µmol/L).
Therefore, it can be concluded that the cytotoxicity of eugenol
occurs in a ROS-independent manner in the presence of
oxidative stress. In another work, it was reported that eugenol
inhibits the enzyme MMP-9 which is related to metastasis
in human fibrosarcoma cells suggesting its application for
prevention of metastasis related to oxidative stress[40].
4. Toxicity and pharmacokinetics
The clove essential oil is generally recognized as safe
substance when consumed in concentrations lower
than 1 500 mg/kg. On the other hand, the World Health
Organization (WHO) established that the daily quantity
acceptable of clove per day is of 2.5 mg/kg of weight in
humans[10]. The toxicity of clove oil was tested in two

Diego Francisco Cortés-Rojas et al./Asian Pac J Trop Biomed 2014; 4(2): 90-96
94
aquarium fish species, Danio rerio and Poecilia reticulata
the medium lethal concentrations (LD50) at 96 h were (18.2依
5.52) mg/mL in Danio rerio and (21.7依0.8) mg/mL in Poecilia
reticulata[41].
Eugenol is easily absorbed when administrated by oral
route reaching rapidly plasma and blood with mean half-
lives of 14.0 h and 18.3 h, respectively. A cumulative
effect has been hypothesized and associated to relieve of
neuropathic pain after repeated daily administrations[42].
5. Agricultural and larvicidal uses
The clove essencial oil may also be employed as
insecticide. Park and Shin reported the possibility of
employment of clove essential oil to control the japonesse
terminte Reticulitermes speratus Kolbe[43]. In the same
way, Eamsobhana et al. found that clove essencial oil at
5% posses 100% of repellent activity against the chigger
Leptotrombidium imphalu which could be a safer and
cheaper alternative to synthetic repelents commonly
associated to harmful side effects[44].
A formulation containing 10% of clove essential oil was
effective against the bit of Aedes aegypti (L.) and Anopheles
dirus Peyton and Harrion with a protection time of (80.33
依10.56) and (60.00依10.00) respectively, soy bean oil was
employed as control[45]. In a recent work, the structure-
activity relationship of the main clove oil constituents
and synthetic derivatives of eugenol against Aedes aegypti
(Diptera: Culicidae) larvae were studied. The larvicidal
methods are one of the most effective strategies to combat
dengue, since there is not drug for treatment or a vaccine.
Eugenol exhibited interesting results and could be a
promising alternative to common insecticide[46].
Eugenol, eugenol acetate and beta-caryophyllene were
effective in repellency of red imported fire ants Solenopsis
invicta (Hymenoptera: Formicidae), being eugenol the
fastest acting compound[47]. Clove oil was also effective
spatial repellent for pestiferous social wasps Vespula
pensylvanica (Saussure) and paper wasps mainly Polistes
dominulus (Christ)[48].
Clove oil can also serve as an anesthesia for a variety
of fish. However, lengthy exposures can cause mortality
and sub-acute morbidity[49]. The most appropriate dose to
anesthetize the angelfish was determined by Hekimoglu
and Ergun[50]. This study will help in the transportation
and handing of this fish which is one of the most stressful
aquarium species.
Clove oil could be employed as suppressor of potato
tuber germination by affecting the lipid peroxidation
and the enzymes activities of catalase, glutathione-S-
transferase, peroxidase, polyphenol oxidase and superoxide
dismutase[51].
6. Conclusion
Based on the information presented, it could be
concluded that clove represents a very interesting plant
with an enormous potential as food preservative and
as a rich source of antioxidant compounds. It’s proved
biological activities suggest the development of medicinal
products for human and animals uses and confirm why this
plant has been employed for centuries.
Conflict of interest statement
We declare that we have no conflict of interest.
Acknowledgements
The authors acknowledge the São Paulo Rese arch
Foundation-FAPESP-Brazil for the financial support (Grant
No. 2012/09890-6).
Comments
Background
Clove (S. aromaticum) is one of the most valuable spices
that have been used for centuries as food preservative and
for many medicinal purposes. Clove is native of Indonesia
but nowadays is cultured in several parts of the world
including Brazil in the state of Bahia. This plant represents
one of the richest source of phenolic compounds such
as eugenol, eugenol acetate and gallic acid and posses
great potential for pharmaceutical, cosmetic, food and
agricultural applications.
Research frontiers
This review includes the main studies reporting the
biological activities of clove (S. aromaticum) and eugenol.
The antioxidant and antimicrobial activity of clove is
higher than many fruits, vegetables and other spices
and should deserve special attention. A new application
of clove as larvicidal agent is an interesting strategy to
combat dengue which is a serious health problem in
Brazil and other tropical countries. Pharmacokinetics and
toxicological studies were also mentioned. The different
studies reviewed in this work confirm the traditional use
of clove as food preservative and medicinal plant standing
out the importance of this plant for different applications.
Related reports
This work is a review documenting the main studies
reporting the biological activities of clove (S. aromaticum)

Diego Francisco Cortés-Rojas et al./Asian Pac J Trop Biomed 2014; 4(2): 90-96 95
and eugenol.
Innovations and breakthroughs
This review includes the main studies reporting the
biological activities of clove and eugenol. Based on the
information presented, it could be concluded that clove
represents a very interesting plant with an enormous
potential as food preservative and as a rich source of
antioxidant compounds. It’s proved biological activities
suggest the development of medicinal products for human
and animals uses and confirm why this plant has been
employed for centuries.
Applications
S. aromaticum (Myrtaceae) commonly known as clove,
is an median size tree (8-12 m) native from the Maluku
islands in east Indonesia. The clove tree is frequently
cultivated in coastal areas at maximum altitudes of 200 m
above the sea level. The production of flower buds, which
is the commercialized part of this tree, starts after four
years of plantation. The collection could be done manually
or chemically-mediated using a natural phytohormone
which liberates ethylene in the vegetal tissue, producing
precocious maturation.
Peer review
In the review, the authors demonstrated the main studies
reporting the biological activities of clove (S. aromaticum)
and eugenol. Based on the information presented, it could
be concluded that clove represents a very interesting plant
with an enormous potential as food preservative and as a
rich source of antioxidant compounds. It’s proved biological
activities suggest the development of medicinal products for
human and animals uses.
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