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Background: The threat posed by drug-resistant pathogens has resulted in the increasing momentum in research and development for effective alternative medications. The antioxidant and antibacterial properties of phytochemical extracts makes them attractive alternative complementary medicines. Therefore, this study evaluated the phytochemical constituents of Melaleuca cajuputi flower and leaf (GF and GL, respectively) extracts and their antioxidant and antibacterial activities. Methods: Radical scavenging capacity of the extracts was estimated using 2,2-diphenyl-2-picrylhydrazyl and Fe(2+)-chelating activity. Total antioxidant activity was determined using ferric reducing antioxidant power assay. Well diffusion, minimum inhibitory concentration, and minimum bactericidal concentration assays were used to determine antibacterial activity against eight pathogens, namely Staphylococcus aureus, Escherichia coli, Bacillus cereus, Staphylococcus epidermidis, Salmonella typhimurium, Klebsiella pneumonia, Streptococcus pneumoniae, and Pasteurella multocida. We identified and quantified the phytochemical constituents in methanol extracts using liquid chromatography/mass spectrometry (LC/MS) and gas chromatography (GC)/MS. Results: This study reports the antioxidant and radical scavenging activity of M. cajuputi methanolic extracts. The GF extract showed better efficacy than that of the GL extract. The total phenolic contents were higher in the flower extract than they were in the leaf extract (0.55 ± 0.05 and 0.37 ± 0.05 gallic acid equivalent per mg extract dry weight, respectively). As expected, the percentage radical inhibition by GF was higher than that by the GL extract (81 and 75 %, respectively). A similar trend was observed in Fe(2+)-chelating activity and β-carotene bleaching tests. The antibacterial assay of the extracts revealed no inhibition zones with the Gram-negative bacteria tested. However, the extracts demonstrated activity against B. cereus, S. aureus, and S. epidermidis. Conclusions: In this study, we found that M. cajuputi extracts possess antioxidant and antibacterial activities. The results revealed that both extracts had significant antioxidant and free radical-scavenging activity. Both extracts had antibacterial activity against S. aureus, S. epidermidis, and B. cereus. The antioxidant and antimicrobial activities could be attributed to high flavonoid and phenolic contents identified using GC/MS and LC/MS. Therefore, M. cajuputi could be an excellent source for natural antioxidant and antibacterial agents for medical and nutraceutical applications.
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R E S E A R C H A R T I C L E Open Access
Antioxidant, antibacterial activity, and
phytochemical characterization of
Melaleuca cajuputi extract
Nazeh M. Al-Abd
1*
, Zurainee Mohamed Nor
1
, Marzida Mansor
2
, Fadzly Azhar
3
, M. S. Hasan
2
and Mustafa Kassim
2
Abstract
Background: The threat posed by drug-resistant pathogens has resulted in the increasing momentum in research
and development for effective alternative medications. The antioxidant and antibacterial properties of phytochemical
extracts makes them attractive alternative complementary medicines. Therefore, this study evaluated the phytochemical
constituents of Melaleuca cajuputi flower and leaf (GF and GL, respectively) extracts and their antioxidant and antibacterial
activities.
Methods: Radical scavenging capacity of the extracts was estimated using 2,2-diphenyl-2-picrylhydrazyl and
Fe
2+
-chelating activity. Total antioxidant activity was determined using ferric reducing antioxidant power assay.
Well diffusion, minimum inhibitory concentration, and minimum bactericidal concentration assays were used to
determine antibacterial activity against eight pathogens, namely Staphylococcus aureus, Escherichia coli, Bacillus
cereus, Staphylococcus epidermidis, Salmonella typhimurium, Klebsiella pneumonia, Streptococcus pneumoniae, and
Pasteurella multocida. We identified and quantified the phytochemical constituents in methanol extracts using
liquid chromatography/mass spectrometry (LC/MS) and gas chromatography (GC)/MS.
Results: This study reports the antioxidant and radical scavenging activity of M. cajuputi methanolic extracts.
The GF extract showed better efficacy than that of the GL extract. The total phenolic contents were higher in
the flower extract than they were in the leaf extract (0.55 ± 0.05 and 0.37 ± 0.05 gallic acid equivalent per mg
extract dry weight, respectively). As expected, the percentage radical inhibition by GF was higher than that by
the GL extract (81 and 75 %, respectively). A similar trend was observed in Fe
2+
-chelating activity and β-carotene
bleaching tests. The antibacterial assay of the extracts revealed no inhibition zones with the Gram-negative bacteria
tested. However, the extracts demonstrated activity against B. cereus, S. aureus,andS. epidermidis.
Conclusions: In this study, we found that M. cajuputi extracts possess antioxidant and antibacterial activities. The
results revealed that both extracts had significant antioxidant and free radical-scavenging activity. Both extracts
had antibacterial activity against S. aureus,S. epidermidis,andB. cereus. The antioxidant and antimicrobial activities
could be attributed to high flavonoid and phenolic contents identified using GC/MS and LC/MS. Therefore, M.
cajuputi could be an excellent source for natural antioxidant and antibacterial agents for medical and nutraceutical
applications.
Keywords: Melaleuca cajuputi, Antioxidant capacity, Total phenol content, Gas chromatography/mass spectrometry
(GC/MS), Liquid chromatography/mass spectrometry (LC/MS)
* Correspondence: Nazehali78@yahoo.com
1
Department of Parasitology, Faculty of Medicine, University of Malaya, 50603
Kuala Lumpur, Malaysia
Full list of author information is available at the end of the article
© 2015 Al-Abd et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Al-Abd et al. BMC Complementary and Alternative Medicine (2015) 15:385
DOI 10.1186/s12906-015-0914-y
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Background
The cells of living organisms generate free-radicals as a
result of pathophysiological and biochemical processes
in response to factors such as environmental pollutants,
radiation, chemicals, and toxins. This creates an imbal-
ance in the formation and neutralization of prooxidants
that subsequently seek stability through electron pairing
with biological macromolecules such as proteins, lipids,
and DNA, leading to oxidative stress in the physiological
system [1]. Furthermore, these effects lead to lipid per-
oxidation as well as protein or DNA damage or both in
human cells. Moreover, the cellular damage consequently
lead to aging and several chronic diseases such as cancer,
diabetes, and atherosclerosis as well as cardiovascular, in-
flammatory, and other degenerative diseases in humans
[1]. The ability of certain phytochemical extracts to inhibit
or delay the oxidation of other molecules by suppressing
the initiation or propagation of oxidizing chain reactions
have made them active alternatives in complementary
medicine. These naturally occurring antioxidant chemicals
have been reported to be composed of phenolic (such as
flavonoids, phenolic acids, and tocopherols) and nitrogen
compounds (alkaloids, chlorophyll derivatives, amines,
and amino acids) as well as carotenoids and ascorbic acid
[2]. In fact, phytochemical extracts containing constituents
such as plant-derived vitamins, flavonoids, alkaloids carot-
enoids, terpenoids, polyphenols, and phenolic compounds
such as caffeic, vanillic, ferulic, and ellagic acids have been
reported to exhibit antioxidant and anticancer activities [3].
Although chemically synthesized antioxidant compounds
such as butylated hydroxytoluene and hydroxyanisole have
been used for several decades, the safety of their continued
use is currently being questioned due to reports of their
carcinogenicity [4]. Therefore, alternative effective anti-
oxidants that have benign or minimal side effects are
highly needed.
Infectious diseases caused by microorganism are a major
cause of mortality and morbidity in humans. Although
several antibiotics have been developed to manage these
diseases with optimum efficacy, their mismanagement and
maladministration, as well as microbial mutation have led
to the emergence of drug-resistant strains. As a result,
over the past decades, antibiotics that are known to cure
specific diseases have lost their effectiveness. Therefore,
the search for new antimicrobial drugs from natural
sources is warranted.
Traditional medicine practices in ancient human civi-
lizations worldwide have demonstrated that plants are
one of the most promising sources of effective medi-
cinal agents. Therefore, scientific studies have been car-
ried out on the antimicrobial activities of plant extracts
against different types of microorganisms, which have
resulted in the development of alternative plant-based
antimicrobial drugs.
Numerous phytochemical extracts have been evaluated
in the process of searching for plant-based antimicrobial
agents and some recently reported studies include those
on Syzygium gratum, Justicia gangetica, and Limnocharis
flava [5], Buglossoides purpurocaerulea [6], Nymphaea
nouchali [7], and Polygonum hydropiper [8]. Melaleuca
cajuputi is commonly known as the Gelam tree and is
used to cure cholera as well as muscle and joint pain in
folk medicine. It is a member of the Myrtaceae family
with reported anti-inflammatory [9], anticancer [10],
hepatoprotective [11], and anthelmintic activities [12].
Studies have revealed the antibacterial activity of es-
sential oils of M. caguputi against Gram-positive and
Gram-negative bacterial strains in the disc diffusion
and minimum inhibitory concentration (MIC) assays.
The extracted oil inhibited the growth of Enterococcus
faecalis, Escherichia coli,Klebsiella pneumoniae,Pseudo-
monas aeruginosa,Salmonella enterica,Staphylococ-
cus aureus, and Streptococcus pyogenes [13, 14].
In this study, we evaluated the in vitro antioxidant and
antibacterial activities of methanolic extracts of the leaves
and flowers of M. cajuputi. In addition, we analyzed the
phytochemical constituents of the extracts using liquid
chromatography (LC)/mass spectrometry (MS) and gas
chromatography (GC)/MS.
Methods
Chemical and reagents
Methanol, sodium hydroxide (NaOH), iron (II) sulfate
(FeSO
4
), iron (II) chloride (FeCl
2
), sodium nitrite, iron (II)
chloride (FeCl
3
), chloroform, hydrochloric acid (HCL), β-
carotene, quercetin, chloragenic acid, tripyridyl-s-triazine
(TPTZ), butylated hydroxytoluene (BHT), propyl gallate,
2,2-diphenyl 1- picrylhydrazyl (DPPH), linoleic acid,
Tween 20, Folin-ciocalteu reagent, acetate buffer, ferro-
zine, ethylenediaminetetraacetic acid (EDTA), ascorbic
acid, and all other reagents and solvents used in this
study were of analytical grade purchased from Merck
(Merck, Darmstadt, Germany).
Plant materials
The plant material used in this study was collected from
Kedah State, Malaysia, in September 2013, and Identity
was confirmed at the Herbarium of Rimba Ilmu, Institute
of Biological Sciences, University of Malaya, Kuala Lumpur
with voucher number KLU048231.
Preparation of methanolic extracts
The leaves and flowers of the Gelam tree (M. cajuputi)
were washed separately with distilled water, ground to a
powder, and then dried in the shade for seven days. The
methanolic extracts were prepared by adding 100 g of
either the Gelam leaves (GL) or Gelam flower (GF) powder
to 1 L of absolute methanol in a conical flask and leaving it
Al-Abd et al. BMC Complementary and Alternative Medicine (2015) 15:385 Page 2 of 13
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
for 72 h at 25 °C. The mixtures were then filtered using
Whatman filter paper (No: 1) to obtain the extract and this
procedure was repeated thrice, followed by in vacuo con-
centration at 40 °C using a rotary evaporator to obtain the
GF and GL extracts.
GC/MS analysis
The GC/MS analysis of the methanol extract was carried
out by sonicating a 10-mg sample for 15 min in 2.5 mL
of dichloromethane at 40 °C in a sealed vial. Then, 1 mL of
the treated extract sample was filtered through a 0.20-μm
nylonfilterintoastandardGC2-mLvialforanalysis.The
GC/MS analyses were performed at an ionization energy of
70 eV while separation of the hydrocarbons and other vola-
tile compounds were determined using a GCMS-QP2010
series GC system (Shimadzu, Japan) equipped with a
DB-5MS Agilent nonpolar column (30 mm × 0.25 mm,
0.25 mm) (Agilent Technologies Inc., Tokyo, Japan). The
oven was initially programmed to run at a temperature of
60 °C for 2 min, followed by an increase of 7 °C/min to
150 °C, with a final hold at 310 °C for 15 min. The injector
and detector temperatures were kept at 300 (split) and
310 °C, respectively. The analysis was performed with He
as the carrier gas at a linear flow rate of 40 cm/s, and the
MS detector was operated at 200 °C while the scan range
was from 501000 m/z at a rate of 0.50 scan/s. To check
the purity of each GC peak, the MS was recorded at vari-
ous parts of each peak. All compounds were putatively
identified using a mass spectral database search (National
Institute of Standards and Technology/ Environmental
Protection Agency/National Institutes of Health, NIST/
EPA/NIH) followed by a comparison with the acquired
MS data to determine the degree of matching. The
compounds that showed mass spectra with match fac-
tors 90 % were included on the positive listof tentatively
identified metabolites.
LC/MS analysis
The LC/MS experiments were conducted to chemically
profilethemethanolicextracts.Thesystemusedtoanalyze
the samples was comprised of an Agilent 1290 Infinity
LC system coupled to an Agilent 6520 Accurate-Mass
quadrupole time-of-flight mass spectrometer with dual
electrospray ionization (ESI) source. The LC separations
were performed using a 2.1 mm (i.d) Narrow-BoreSB-C18
(length 150 mm, particle size 3.5 mM) analytical column.
The LC parameters used were: autosampler temperature,
25 °C; injection volume, 0.5 μL; column temperature, 25 °C;
and flow rate, 0.4 mL/min. A gradient system consisting of
solvents A (0.1 % formic acid in water) and B (0.1 % formic
acid in acetonitrile) was employed. The mass spectra data
were acquired using an ESI capillary voltage of (+) 4000 V
and () 4000 V in the positive and negative ion modes,
respectively with the fragmentor at 125 V. For the
other conditions, the liquid nebulizer was set to 45 psi,
the nitrogen drying gas was set at a flow rate of 10 L/
min with the drying gas and vaporizer temperatures
maintained at 300 °C, and the ionization interface was
operated in both positive and negative modes. The data
were acquired at a rate of 1.03 spectra/s with a stored
mass range of 1003200 and 1153200 m/z for the
positive and negative modes, respectively. The data were
collected using the Agilent Mass Hunter Workstation
Data acquisition software. LC/MS data files were proc-
essed using the Agilent Mass Hunter Qualitative Analysis
B.05.00 software. Feature finding was achieved by using
the molecular feature extraction and correlation algo-
rithms, which located the groups of covariant ions in each
chromatogram. In the positive-ion mode, this included ad-
ducts H
+
,Na
+
,K
+
,andNH
4
+
and in the negative-ion mode,
adducts H
and Cl
.
Total flavonoid assay
The total flavonoid content of the methanolic extracts was
determined photometrically using the aluminum chloride
(AlCl
3
) assay [15]. Briefly, a 1-mL aliquot of each extract
(1 mg/mL) or standard solution of quercetin (31.5, 62.5,
125, 250, 500, and 1 mg/L) was added to a volumetric flask
(10-mL) and diluted with 4 mL double distilled water at
time 0. Then, 0.3 mL of 5 % (w/v) sodium nitrite (NaNO
2
)
was added and after 5 min, 0.6 mL AlCl
3
(10 %) was
added. At 6 min, 2 mL of sodium hydroxide (NaOH, 1 M)
was added to the mixture, and the final total volume was
made up to 10 mL with double-distilled water. The solu-
tion was mixed completely, and the absorbance was mea-
sured against a prepared reagent blank in triplicate at
430 nm. The total flavonoid content was expressed as
quercetin equivalents in mg/100 g of dry extract weight.
Total phenolic content (TPC)
The TPC of the methanolic extracts was determined
using the Folin-Ciocalteu reagent (Sigma-Aldrich Chem-
ical Co., St. Louis, MO, USA) as previously described by
Kim et al. [16], with slight modifications. Briefly, 100 μLof
each extract or standard solution of gallic acid (16
1000 μg/mL in 80 % methanol) was mixed with 200 μLof
Folin-Ciocalteu reagent, followed by 2 mL of deionized
water and 1 mL of 15 % sodium bicarbonate (Na
2
CO
3
).
Then, the mixture was incubated for 120 min at room
temperature, and the absorbance was measured at 765 nm
in triplicate using an ultraviolet (UV)-Visible (Vis) spec-
trophotometer (GBC, Cintra 40). The total phenolics were
quantified using a calibration curve constructed from
measurements of the standard gallic acid concentrations
and expressed as mg gallic acid equivalent (GAE) per mg
of extract weight.
Al-Abd et al. BMC Complementary and Alternative Medicine (2015) 15:385 Page 3 of 13
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Determination of antioxidant activity using DPPH radical
scavenging
The antioxidant activity of the extracts was measured by
determining the hydrogen donating or radical scaven-
ging ability, using the stable radical, DPPH as reported
previously [17]. An aliquot (120 μL) of 0.25 mM DPPH
solution in methanol and 30 μL of each extract at in-
creasing concentrations (31.3, 62.5, 125, 250, 500, and
1000 μg/mL) were mixed vigorously together and left at
room temperature in the dark. The absorbance was mea-
sured at 518 nm after 30 min against different concen-
trations of the extracts in methanol as blanks and DPPH
in methanol without extract as the control. The standard
synthetic antioxidant, butylhydroxytoluene was used as
the positive control. The percentage antiradical activity
(AA%) of the extracts was calculated using the following
formula [15],
AA%¼100
AbssampleAbsblank
Abscontrol

100

Where, Abs
sample
, Abs
blank
, and Abs
control
are the absorb-
ance values of the extract, blank, and control samples,
respectively.
β-Carotene bleaching test
The β-carotene bleaching test was used to evaluate the
antioxidant activities based on the β-carotene lenolate
system model [18], with slight modifications. Briefly,
1mLofβ-carotene solution (0.2 mg/mL in chloroform)
was added to 0.02 mL of linoleic acid and 0.2 mL of
100 % Tween 20. Then, 5 mL samples of this emulsion
were transferred into test tubes containing 0.2 mL of test
samples in 80 % methanol at increasing concentrations
(62.5, 125, 250, 500, and 1000 μg/mL). These mixtures
were then incubated in a water bath at 40 °C for
120 min. All determinations were performed in duplicate
and the mean values calculated. The absorbance was
measured at 470 nm using a PerkinElmer Lambda 40
UV/Vis spectrophotometer against a blank consisting of
the emulsion without β-carotene. The measurements were
carried out at initial and final times (t = 0 and 120 min,
respectively) with propyl gallate as the positive control.
The AA% was measured and expressed as the percentage
of inhibition of β-carotene oxidation using the following
equation:
AA%¼AS0AS120
AC0AC120

100
Where AS
0
and AS
120
are absorbance values of the samples
and AC
0
,andAC
120
are the controls at 0 and 120 min,
respectively.
Fe
2+
-chelating activity assay
The Fe
2+
-chelating activity of GL and GF extracts was
measured as follows: The extract was treated with ferro-
zine (5 mM), which reacted with the divalent iron to
form a stable and highly water-soluble magenta complex
species. After 10 min at room temperature, the absorbance
of the Fe
2+
ferrozine complex was measured at 562 nm.
The Fe
2+
-chelating activity of the extract was calculated
using the following equation:
%Chelating rate ¼A0A1
A0 100
Where, A
0
and A
1
are the absorbance values of the con-
trol (blank without extract) and in the presence of the
extract, respectively.
Ferric reducing antioxidant power (FRAP) assay
The ferric reducing power of the extracts was assayed
based on the blue coloration that developed due to the
reduction of ferric iron to the ferrous form as described
previously [18]. Extract solutions were prepared by dis-
solving about 0.1 μg/mL of extracts in ethanol. An ali-
quot (0.2 mL) of each extract solution was added to a
test tube containing 1.8 mL of freshly prepared FRAP re-
agent that consisted of 2.5 mL of 10 mM TPTZ solution
in 40 mM of HCl and 2.5 mL of 20 mM FeCl
3
.6H
2
Oin
25 mL of 0.3 M acetate buffer (pH 3.6). The mixture
was incubated at 37 °C for 5 min. The spectrometric ab-
sorbance was recorded at 593 nm. The reducing power
was ascertained by comparing the spectrophotometric
absorbance of each sample against a standard curve ob-
tained from Fe
2
SO
4
.
Antimicrobial activity
Test organisms
The in vitro antibacterial activities of the M. cajuputi
extracts were evaluated against eight strains that were
supplied by the Microbiology Laboratory of the Univer-
sity of Malaya Medical Centre. They comprised of four
Gram-positive (Staphylococcus epidermidis,MTCC3615;
Staphylococcus aureus, RF 122; Bacillus cereus,ATCC
11778;and Streptococcus pneumoniae, ATCC 10015)
and four Gram-negative (Escherichia coli,UT181;Sal-
monella typhimurium, ATCC 14028; Klebsiella pneumo-
nia, ATCC13883; and Pasteurella multocida, a clinically
isolated strain) bacterial strains. All the strains were stored
in the appropriate medium before use.
Inocula preparation
The colony suspension method was used to prepare the
inocula of the test organisms. The bacterial strains were
grown on nutrient agar (NA) at 37 °C for 18 h, and then
adjusted to a turbidity of 0.5 McFarland standards (10
6
Al-Abd et al. BMC Complementary and Alternative Medicine (2015) 15:385 Page 4 of 13
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
colony forming units, CFU/mL) based on the optical
density (OD) measurement at 620 nm. After being cul-
tured for 24 h on NA, the colonies were collected, and
cultured in nutrient broth medium for 24 h at 37 °C.
The susceptibility tests were subsequently performed using
the NA-well diffusion method.
Bacterial cultures and disc diffusion assay
The disc diffusion method is a widely acclaimed method
used in screening crude extracts for antibacterial activities.
In this study, the antibacterial activity was determined
based on the method previously described [19] with
modifications. Briefly, the crude extract at a concentration
of 0.1 g/mL was dissolved in 100 % dimethyl sulfoxide
(DMSO, Merck, Germany) and sterilized by filtration
using a 0.20-mm Millipore disposable filter (Minisart,
Sartorius Biotech, Germany). Autoclave-sterilized (121 °C
for 20 min) Mueller Hinton Agar (MHA) medium (BioLab)
was used in the disc diffusion assay. A 50-μLsampleofthe
filtration-sterilized plant extract was loaded onto a sterile
paper disc (6 mm in diameter), which was then placed on
the surface of the agar plate (NA) previously inoculated
with the bacteria. A disc prepared under the same con-
ditions with only 50 μL of DMSO was used as a negative
control. In addition, a similar disc was loaded with the
reference antibiotic (streptomycin) at a concentration
of 20 mg of drug per disc and used as described above.
Both samples were allowed to diffuse into the agar
plates for 1 h and were then inverted and incubated at
37 °C for 18 h. Antibacterial activity was determined by
measuring the diameter of the growth inhibition zones
(IZs, mm) surrounding each disc. Each assay was per-
formed in triplicate with two repetitions and the results
were expressed as average values.
MIC and minimal bactericidal concentration (MBC) assays
The MIC values, which represent the lowest plant ex-
tract concentration that completely inhibits the growth
of microorganisms, were determined using a micro-well
dilution method as described previously [20]. In addition,
the MBC values refer to the lowest concentration of an
antibacterial agent required to prevent the growth of a
particular bacterium after subculture in an antibiotic-free
medium. Briefly, the extracts were dissolved in DMSO at
100 mg/mL, and then twofold serial dilutions were pre-
pared in a 96-well dilution microplate. The antibiotic
streptomycin was included as reference agent in each
assay while the extract-free solution was used as a blank
control. Each well of the microplates contained 40 μLof
growth medium, 10 μL of inoculum (10
6
CFU/ml), and
50 μL of diluted sample extracts. Then, the microplates
were incubated overnight at 37 °C. As an indicator of
microorganism growth, 40 μL of p-iodo nitro tetrazolium
violet (INT) dissolved in water was added to the wells, and
the plates were incubated at 37 °C for 30 min. The color-
less tetrazolium salt acts as an electron acceptor and is re-
duced to a red-colored formazan product by biologically
active organisms [20]. A Tecan microplate reader (Infinite
M200PRO) was used to quantify the OD of the reactants
in each well. Where microbial growth was inhibited, the
solution in the well remained clear after incubation with
INT. The determination of MIC values was performed in
triplicate. The MBC of the extracts was determined by
subculturing samples from the MIC assay tubes onto NA
plates from wells that showed growth inhibition, and then
subsequently determining the dilution at which growth
was arrested, which was considered the MBC.
Statistical analysis
The data were expressed as mean ± standard deviation
(SD) of triplicate determinations. The half-maximal inhibi-
tory concentrations (IC
50
) values were estimated from the
AA% versus concentration plots using a non-linear regres-
sion algorithm.
Results and discussion
In this study, we evaluated the chemical constituents of
GL and GF using preliminary GC/MS and LC/MS ana-
lysis. Furthermore, we determined their antioxidant and
antibacterial activities using various in vitro methods.
GC/MS and LC/MS analysis of GF and GL from M. cajuputi
The phytochemical analyses of plant extracts are normally
performed using diverse quantitative and qualitative
analytical techniques spanning from chromatography
to spectroscopy [21]. Previously, K-L Li and S-J Sheu
[22] used a micellar electrokinetic capillary chromato-
graphic method to analyze the phytochemical constituents
of scute-coptis, a dual herbal combination. Using this
method, the researchers identified six scute flavonoids
namely baicalin, wogonin 7-O-glucuronide, oroxylin A
7-O-glucuronide, baicalein, wogonin, and oroxylin A as
well as four coptis alkaloids comprising of berberine,
palmatine, coptisine, and epiberberine.
In another study, GC/MS was used to characterize the
chemical content of Melaleuca essential oils [2325].
Similarly, silica gel chromatography was used to isolate a
new chromone from M. cajuputi leaf extracts [26]. Using
a combination of spectroscopic techniques, the study
characterized the newly isolated chromonone as mela-
chromone [26].
Similarly, in this study, preliminary compound identifica-
tion and quantitation was performed using GC/MS and
LC/MS. As expected, flavonoids and alkaloids were consist-
ently present in all samples. Furthermore, the occurrence of
terpenoids, saponins, glycosides, and steroids depended on
the type of plant part extract analyzed. The occurrence of
the identified compounds mentioned in Tables 1, 2 and 3
Al-Abd et al. BMC Complementary and Alternative Medicine (2015) 15:385 Page 5 of 13
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
in this study has been previously reported in Melaleuca
extracts [27, 28].
As it can be seen in Table 1, the GC/MS analysis of
the GF revealed that the major compounds are essential
oils, characterized by the presence of fatty acids includ-
ing octadecanoic (0.68 %), hexadecanoic (0.60 %), and
9,12-octadecadienoic acids (1.90 %). Additionally, there
were phenolic compounds such as alpha-tocopherol
(vitamin E, 0.47 %), ethanone (4.34 %), 1,4-naphthalene-
dione (1.07 %), and terpenoid compounds such as Urs-
12-en-28-al (6.40 %). Furthermore, aromatic compounds
such as naphthalene (7.92 %) and alpha-tetralone (6.24 %)
were detected. Previous studies have demonstrated that
some of the identified compounds in the GF extract
such as alpha-tocopherol [29] and hexadecanoic acid
[30] possess antioxidant activities.
GC/MS analysis of the GL extract revealed the presence
of 31 phytochemical compounds. As shown in Table 2, the
methanol extract predominantly contained aromatic com-
pounds such as alpha-tetralone (7 %) and 1,4-naphthale-
nedione (4.53 %); phenolic compounds such as ethanone
(11.6 %); terpenoids such as caryophyllene bicyclo [7.2.0]
undec-4ene (3.64 %), naphthalene (3.79 %), and sitosterol
(2.37 %); and flavonoids such as 4H-1-benzopyran-4-one
(6.09 %). In addition, squalene (2.05 %) and octadecanoic
acid (1.31 %) were also present. Furthermore, numerous
Table 1 List of major compounds identified from M. cajuputi Laef extract
ID Posibble Compound Name Class of compound Mol. formula Mol mass Rt time (min) %
1 3-Cyclohexen-1-ol Terpenoids C18H18O 154 6.152 1.08
2 Cyclohexane, 1-ethenyl-1-methyl-2,4bis(1-methylethenyl) Terpenoids C15H24O4 204 8.109 1.83
3 Caryophyllene Bicyclo[7.2.0]undec-4ene Terpenoids C15H24 204 8.589 3.64
4 Caryophyllene 1,4,8-Cycloundecatriene Terpenoids C15H24 204 9.061 2.32
5 Naphthalene Terpenoids C15H24 204 9.537 2.13
6 Naphthalene Terpenoids C15H24 204 9.619 1.66
7 1H-Cycloprop[e]azulen-7-ol Terpenoids C15H24O 220 10.914 2.27
8 Caryophyllene oxide 5-Oxatricyclo[8.2.0.0(4,6)-]dodecane Terpenoids C15H24O 220 11.046 2.0
9 Alpha.-Tetralone Aromatic C12H13FO3 224 11.308 7.0
10 2-Naphthalenemethano Sesquiterpene C15H24O 222 12.325 2.38
11 Spathulenol 1H-Cycloprop[e]azulen-7ol Sesquiterpene C15H24O 222 13.636 1.31
12 Ethanone Phenolic C10H10O5 210 15.181 2.83
13 3,7,11,15-Tetramethyl-2-hexadecen-1ol $$ (2E)-3 Fatty acid C20H40O 296 15.708 2.50
14 3-Eicosyne 3-Icosyne Straight chain C20H38 278 16.634 0.87
15 4H-1-Benzopyran-4-one Flavone C11H10O4 206 16.791 1.38
16 1,4-Naphthalenedione Aromatic C11H8O5 220 18.750 4.53
17 4H-1-Benzopyran-4-one Flavonoids C11H8O5 220 19.298 6.09
18 Ethanone phenolic C16H14O4 234 19.713 8.81
19 Methyl lathodoratin Flavonoids C12H12O4 220 20.921 0.57
20 Phytol 2-Hexadecen-1- Fatty acids C20H40O 296 21.666 0.57
21 Octadecanoic acid Fatty acid C22H44O2 340 27.517 1.31
22 1-Heptacosanol Straight chain C27H56O 396 33.437 0.27
23 Squalene Straight chain alkene C30H50 410 35.458 2.05
24 1-Heptacosanol Straight chain C27H56O 396 33.437 0.27
25 2H,6H-Pyrano[3,2-b]xanthen-6-one Flavonoids C18H14O6 326 39.607 0.41
26 Alpha Tocopherol (vit E) Phenolic C29H50O2 430 43.406 2.37
27 Sitosterol, Stigmast-5-en-3-ol Terpenoids C29H50O 414 43.406 2.37
28 Urs-12-en-28-al Terpenoids C30H48O 424 44.485 0.95
29 Dammarane-3,12,25-triol Terpenoids 562 47.086 0.55
30 Betulin Lup-20(29)-ene-3,28-diol Terpenoids C30H50O2 482 47.947 1.15
31 Urs-12-en-28-al Terpenoids C30H48O 424 50.881 0.96
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previous studies have reported the antioxidant activities of
some of these compounds [31, 32].
The results of the LC/MS analyses are presented in
Table 3. Most of the observed compounds were typical
hydroxycinnamic acid and phenolic acid derivatives
(Fig. 1). The LC/MS analysis of the GF extract indicated
the presence of caffeic acid phenyl ester, gingerol, aspi-
din, methyl orsellinic acid ester, ethyl ester, trans-2,3, 4-
trimethoxycinnamate, and metyrosine. In addition, the
GL extract contained epigallocatechin 3-O-(4-hydroxy-
benzoate), 5,6,3'-trimethoxyflavone, metyrosine, gingerol,
polygonolide, and trans-2, 3, 4-trimethoxycinnamate.
Total phenolic, total flavonoids contents, and antioxidant
activity
Numerous phenolic metabolites containing an aromatic
arene (phenyl) ring with one or more acidic hydroxyl
residues attached to it are known to be produced by
plants. A previous study showed that compounds such
as flavonoid and tannins were among the major phenolic
constituents present in plant extracts [33]. The phenolic
radicals were reported to be less reactive and with a
lower electron reducing potential than the oxygen radi-
cals had [33, 34]. Because of these properties, phenolic
compounds are considered excellent radical scavengers.
Table 2 List of major compounds identified from Gelam flower extract
ID Posibble Compound Name Class of compound Mol. formula Mol mass Rt time (min) %
1 3-Cyclohexen-1-ol Terpenoid C18H18O 154 6.151 1.07
2 Cyclohexane, 1-ethenyl-1-methyl-2-(1methylethenyl)-4-(1-methylethylidene)- Terpenoid C15H24 204 7.482 0.68
3 Copaene Terpenoid C15H24 204 7.997 1.66
4 Cyclohexane, 1-ethenyl-1-methyl-2,4bis(1-methylethenyl) Terpenoid C15H24O4 204 8.107 2.60
5 Caryophyllene Bicyclo[7.2.0]undec-4ene Terpenoid C15H24 204 8.588 6.14
6 1,6-Cyclodecadiene, 1-methyl-5methylene-8-(1-methylethyl)-, Terpenoid C15H24 204 8.690 1.49
7 Caryophyllene 1,4,8-Cycloundecatriene Terpenoid C15H24 204 9.059 3.16
8 Naphthalene Aromatics C15H24 204 9.536 3.26
9 Naphthalene Aromatics C15H24 204 9.616 2.66
10 Naphthalene Aromatics C15H24 204 9.851 1.97
11 1H-Cycloprop[e]azulen-7-ol Terpenoid C15H24O 220 10.906 1.29
12 Caryophyllene oxide 5-Oxatricyclo[8.2.0.0(4,6)-]dodecane Terpenoid C15H24O 220 11.176 1.73
13 Alpha.-Tetralone Aromatics C12H13FO3 224 11.279 6.24
14 2-Naphthalenemethanol Aromatics C15H26O 222 12.318 2.84
15 2-Naphthalenemethanol Aromatics C15H26O 222 15.545 0.98
16 Hexadecanoic acid Fatty acid C17H34O2 270 17.648 0.60
17 1,4-Naphthalenedione Phenolic C11H8O5 220 18.672 1.07
18 4H-1-Benzopyran-4-one Flavonoids C16H20O4 276 19.168 2.12
19 Ethanone Phenolic C16H14O4 234 19.563 4.34
20 9,12-Octadecadienoic acid (Z,Z)-, Fatty acids C19H34O2 294 21.327 1.90
21 Octadecanoic acid Fatty acid C19H38O2 298 22.779 0.68
22 1-Heptacosanol Straight chain C27H56O 396 40.363 0.85
23 Alpha Tocopherol (vit E) Phenolic C29H50O2 430 40.600 0.47
24 Sitosterol, Stigmast-5-en-3-ol Terpenoids C29H50O 414 42.438 0.57
25 Sitosterol, Stigmast-5-en-3-ol Terpenoids C29H50O 414 43.399 3.88
26 Urs-12-en-28-al Terpenoids C30H48O 424 44.480 1.47
27 Urs-12-en-28-al Terpenoids C30H48O 424 45.816 4.93
28 Urs-12-en-28-al, 3-(acetyloxy)-, Terpenoids C32H50O3 482 47.628 1.49
29 Betulin $$ Lup-20(29)-ene-3,28-diol, Terpenoids C30H50O2 442 47.949 3.68
30 Urs-12-en-28-al Terpenoids C30H48O 424 48.690 3.00
31 3.beta.-Myristoylolean-12-en-28-ol Terpenoids C44H76O3 652 50.431 1.67
32 Urs-12-en-28-al Terpenoids C30H48O 424 50.867 2.41
Al-Abd et al. BMC Complementary and Alternative Medicine (2015) 15:385 Page 7 of 13
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Furthermore, phenolic compounds are able to scavenge
reactive oxygen intermediates without invoking further
oxidative reactions. Therefore, one of the current stan-
dards of phytochemical research is the evaluation of the
TPC as a measure of determining the antioxidant activ-
ity of extracts. Therefore, the current study evaluated
the TPC of the extracts and found that the GF extract
showed a higher value than the GL extract did (55 ± 0.05
and 37 ± 0.05 GAE/mg extract dry weight, respectively).
A similar trend was also observed with the flavonoids
content of both extracts (Table 4, GF > GL extracts).
However, it is not surprising that the higher TPC value
of the GF confers a stronger antioxidant ability than that
of the GL. Therefore, the higher the TPC content of an
extract, the higher its antioxidant activity will be. This is
because the substituted 5,7,3,4-hydroxy flavonoids are
believed to possess a very efficient radical scavenging
power [35]. This observation was in agreement with the
report of a direct relationship between the flavonoid and
phenolic contents and the biological activities of plant
extracts [3638].
DPPH radical scavenging activity
The direct and rapid reaction between DPPH radicals
and antioxidants has been utilized as a measure of anti-
oxidant activity [39] and a high percentage DPPH radical
scavenging of a compound indicates excellent activity. In
this present study, the free-radical scavenging activity of
the GL and GF methanolic extracts, which was evaluated
using DPPH, was found to agree with TPC observation.
Therefore, the extract with the higher TPC value also
showed a higher percentage DPPH radical scavenging
activity (Fig. 2). Furthermore, in agreement with the
TPC and flavonoid observations, the percentage radical
inhibition by GF extract was also higher than that of
the GL extract was (81 and 75 %, respectively). This ob-
servation confirmed that both the GF and GL extracts
exhi bit ed DPPH radical-scavenging activity concentration-
dependently, although only the GL extract showed a scaven-
ging power that was greater than the values obtained
with the BHT positive control. For both samples, how-
ever, increasing the concentration beyond 250 μg/mL
resulted in a negligible increase in the radical scavenging
activity (Fig. 2). Based on the calculated IC
50
values, only
the GL extract revealed a higher scavenging effect than
the GF extract by demonstrating a lower IC
50
value
(10 μg/mL) than the positive control BHT (13 μg/mL); the
GF extract showed an IC
50
value of 25 μg/mL. Several re-
ports have indicated that free radical scavenging activity is
greatly influenced by the phenolic contents of the sample,
flavonoid, and the presence of hydroxycinnamic acids such
as caffeic acid phenyl ester [4042]. Similarly, high anti-
oxidant activity was previously reported in Melaleuca [43].
Fe
2+
-chelating activity
In cellular lipid peroxidation determination, the Fenton
reaction is used in metal chelating activity assays to reduce
the concentration of the catalyzing transition metal. This
kind of chelating reaction is considered significant in
reducing the oxidative stress generated by reactive oxygen
species. The chelating effect of the methanolic extracts
was around 50 % at an extract concentration of around
0.4 mg/mL, and the chelating activity was concentration-
dependent (Fig. 3). As expected, the activity of the GF
extract was higher than that of the GL extract was, with
maximum chelating activities of ~75 and 59 %, respectively
(Fig. 3). The presence of a significant amount of caffeic acid
phenyl ester in the GF may have contributed to this activity
Table 3 Chemical composition comparison of methanol extract from flower, and leaves extract of M. cajuputi based on LCMS
Phytochemical extract GF extract GL extract RT m/z
presence % Abundance presence % Abundance
Metyrosine + 0.6 + 0.39 13.072 194.08203
Methylorsellinic Acid, Ethyl Ester + 0.74 + 8.02 11.18 209.0822
Hydroxyibuprofen + 1.2 + 0.74 10.759 221.1184
Trans-2, 3, 4-Trimethoxycinnamate + 0.7 + 11.61 10.386 237.07724
Gingerol + 0.45 + 0.28 11.768 293.17629
Catharanthine + 2.1 + 1.0 20.202 371.15374
calicoferol D + 1.1 + 0.65 21.489 409.31181
Caffeic acid Phenethyl ester (CAPE) + 18.69 - - 18.451 283.30206
Aspidin + 0.65 + 0.59 12.819 459.20282
Cucurbitacin F + 1.2 + 1.2 20.886 517.31874
Kurilensoside G + 2.2 + 3.1 20.89 633.33896
1α,22,25-trihydroxy-26,27-dimethyl-23,23,24,24-tetradehydro-24a,24b,
24c-trihomovitami
+ 9.68 + 9.48 20.869 497.36525
Rt Retention time (as min), m/z mass
Al-Abd et al. BMC Complementary and Alternative Medicine (2015) 15:385 Page 8 of 13
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Fig. 1 Chemical structure of the observed phytochemical compounds in M. cajuputi flower and leaves extracts
Table 4 A comparison of total phenolic and flavonoids contents
Methanolic Extract Total phenolic content (GAE/mg dw) Total flavonoid content (QE/mg dw)
M. cajuputi flower extract 55 ± 0.03 19.6 ± 0.4
M. cajuputi leaves extract 37 ± 0.02 10.2 ± 0.2
GAE Garlic Acid Equivalent
QE Qurcetin Equivalent
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as these substances have been reported to exhibit strong
chelating activity [44].
All the samples tested exhibited a logarithmic increase
in chelating power with increasing concentrations up to
0.25 mg/mL and, thereafter, the percentage chelating
activity appeared to increase gradually.
β-Carotene bleaching test
Carotenoids are among the most common natural pig-
ments and are responsible for most of the red, orange, and
yellow coloration of plant leaves, fruits, and flowers [45].
Currently, more than 600 different carotenoid compounds
were reported to have been characterized [45]. In animals,
carotenoids act as antioxidants. Furthermore, carotenoids
have attracted much attention because numerous studies
have revealed that their consumption is correlated with a
diminished risk for several degenerative disorders includ-
ing various types of cancer and cardiovascular or ophthal-
mological diseases [45]. This effect is attributed to their
antioxidant activity, which protects cells and tissues from
oxidative damage [45]. In this study, all the analyzed
samples inhibited the discoloration of β-carotene in a
concentration-dependent manner (Fig. 4). Generally, an
increase in the percentage inhibition was observed with
Fig. 2 Antioxidant activity of M. cajuputi flower and leaves extracts following DPPH radical scavenging assay
Fig. 3 Metal chelating activity of M. cajuputi flower and leaf extracts
Al-Abd et al. BMC Complementary and Alternative Medicine (2015) 15:385 Page 10 of 13
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
all the samples tested. As expected, the GF extract was
more effective than the GL extract was with inhibition
rates of 71 and 47 %, respectively.
FRAP assay
The FRAP assay is primarily based on the principle of
reduction of ferric ions to their ferrous form at a lower
pH, which results in the formation of a chromatic ferrous-
tripyridyltriazine complex [46]. This assay is considered to
be an accurate method for testing the antioxidant power
of therapeutic compounds [47]. In this research study, the
FRAP antioxidant ability of the M. cajuputi extracts in re-
ducing the Fe
3+
TPTZ reagent was evaluated and both
extracts (GL and GF) demonstrated some reducing power
with FRAP values of 0.12 and 0.14 μM Fe(II)/g, respect-
ively. The presence of a significant amount of caffeic acid
phenyl ester in the GF extract likely contributed to its
higher FRAP value than that of GL extract since this
compound is known to possess strong FRAP antioxidant
activity [44]. Zunjar and colleagues [36] reported that
the reducing capacity of a compound may serve as a re-
markable indicator of its antioxidant activity and ability
to ameliorate oxidative stress by reacting with certain
precursors.
Antibacterial activity
The antibacterial activity of the M. cajuputi extracts
was evaluated against four Gram-positive (B. cereus,S.
epidermidis,S. aureus,andS. pneumoniae)andfour
Gram-negative (E. coli,P. multocida,K. pneumoniae, and
S. typhimurium) bacteria. The antibacterial activity of the
extracts was assessed by determining their IZ, MIC, and
MBC values (Tables 5 and 6).
The results revealed that both the GL and GF extracts
potently inhibited S. epidermidis,S. aureus, and B. cereus
(Table 5). The GF extract was more effective than GL
against S. epidermidis and B. cereus, while both extracts
showed comparable activity against S. aureus. However,
both extracts had no effect against the tested Gram-
negative organisms and P. multocida. The most susceptible
Fig. 4 Antioxidant activity of M. cajuput flower and leaf extracts determined by β-carotene bleaching test
Table 5 Antibacterial activity of crude extracts
Inhibition diameter (mm ± SD)
Sample Staphylococcus
epidermidis
(Gram + ve)
Staphylococcus
aureus
(Gram + ve)
Bacillus
cereus
(Gram + ve)
Pasteurllamultocida
(Gram + ve)
Klebsiella
pneumonia
(Gram + ve)
Streptotococcus
pneumonia
(Gram + ve)
Esherichia
coli
(Gram -ve)
Salmonella
typhimurium
(Gram -ve)
M.cajuputi
Leaves
13.66 ± 0.43 12.33 ± 0.57 6.33 ± 0.33 - - - - -
M.cajuputi
flower
17.33 ± 0.36 12.33 ± 0.31 12.33 ± 0.48 - - - - -
Streptomycin
sulfate
a
20.33 ± 0.38 18.0 ± 0.2 21.0 ± 0.25 21.0 ± 0.05 20.0 ± 0.1 22.0 ± 0.08 15.0 ± 0.1 10.0 ± 0.2
a
Doses of Streptomycin was 1 mg/ml
-No Activity observed
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Content courtesy of Springer Nature, terms of use apply. Rights reserved.
bacteria to the GF extract were S. aureus,S. epidermidis,
and B. cereus with MIC values of 12.5, 12.5, and 25 g/mL,
respectively. Furthermore, the results showed there were
no observed MIC and MBC values against B. cereus ex-
posed to the GL extract (Table 6). However, the exposure
of S. aureus to both extracts resulted in identical MIC, and
MBC values 12.5, and 25 mg/mL, respectively.
The MBC for the GF extract against S. epidermidis
was 25 mg/mL, which was more effective than the GL
extract was at 50 mg/ml. These findings are of great
significance, especially in the case of S. aureus and B.
cereus that are well-known for being resistant to nu-
merous antibiotics. In addition, these organisms are
capable of producing several types of enterotoxins that
can cause septicaemia and several forms of enteritis. In
general, the GF extract was found to be active against
some species of Staphylococci and Bacilli while the GL
extract was inactive against the tested Bacilli.There-
fore, the antibacterial activity of the extracts could be
correlated with their phenolic and flavonoids contents.
KA Hammer, C Carson and T Riley [13] reported a
similar observation for the antimicrobial activity of M.
cajuputi extract against S. aureus.Incontrast,itwasre-
ported that the hexane, dichloromethane, and acetone
extracts of M. cajuputi leaves showed no activity against S.
aureus,methicillin-resistantS. aureus,E. coli,andP. aeru-
ginosa [26].
Conclusions
We attempted to explore the diverse phytochemical ef-
ficacy of M. cajuputi against several diseases and oxidative
stress, by evaluating the antioxidant and antibacterial ac-
tivities of its GF and GL methanolic extracts. Furthermore,
to the best of our knowledge, this is the first comprehen-
sive study of the antioxidant and antibacterial potential of
the GF and GL extracts. Generally, the GF extract showed
a higher efficacy than the GL extract did. In addition, the
TPCs were higher in the GF extract than they were in the
GL extract, and these results were in agreement with the
percentage radical inhibition results, which were higher
for the GF extract than they were for the GL extract.
The same trend was also observed in the Fe
2+
-chelating
activity, flavonoid contents, and β-carotene bleaching
test. Both extracts showed promising evidence of anti-
bacterial activity against S. aureus,S. epidermidis,and
B. cereus. Finally, the observed antioxidant and antibac-
terial activities of these extracts could be attributed to
the high content of phenolics and flavonoids identified
using LC/MS and GC/MS.
Competing interests
The authors declare that they have no competing interests.
Authorscontributions
NMA participated in all face of the study, collection plant, conceived of the
study, design and wrote the manuscript, ZMN design the study and rewrote
the final one. MM, MSH supervised part of the study and reviewed the
manuscript. MK participated in the design and coordination. FA participated
in the chemistry part. All authors read and approved the final manuscript.
Acknowledgement
The authors are grateful to University of Malaya for research grant PG085-
2012B. The authors acknowledge the contribution of Abdulwali and azdren
for the technical assistance in antioxidant and antibacterial activity.
Author details
1
Department of Parasitology, Faculty of Medicine, University of Malaya, 50603
Kuala Lumpur, Malaysia.
2
Department of Anesthesiology, Faculty of Medicine,
University of Malaya, 50603 Kuala Lumpur, Malaysia.
3
Department of
Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur,
Malaysia.
Received: 22 February 2015 Accepted: 13 October 2015
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... Plants are the sources of medicinal compounds that have been used by humans for a long time [1]. Plants are used in this way because they have various components, such as essential oils (EOs), which can have significant potencies as medicinal ingredients [1,2]. ...
... Plants are the sources of medicinal compounds that have been used by humans for a long time [1]. Plants are used in this way because they have various components, such as essential oils (EOs), which can have significant potencies as medicinal ingredients [1,2]. EOs can be defined as plant secondary metabolites that are volatile and provide either tastes or smells [3]. ...
... Even though the oil has been widely used, there are a few research reports on antibacterial activity of cajuput oil. Studies of cajuput oil have been limited to the measurement of its bacterial inhibition zone at one concentration [1,3,13,14]. Therefore, this research aims to determine the effect of varying cajuput oil concentration on its inhibition activity against three bacteria, i.e. ...
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The kinetics of antibacterial activity of cajuput oil (Melaleuca cajuputi) to E. coli, B. cereus, and S. aureus were investigated. The aim of this study was to determine the reaction orders of cajuput oil as an antibacterial agent. The extraction of cajuput oil was conducted by water-steam distillation. The yield was 0.88%. GC-MS analysis showed that the cajuput oil contained β-ocimene (19.35%), 1.8-cineole (17.67%), limonene (12.09%), β-caryophyllene (9.51%), γ-terpinene (8.93%), 2-β-pinene (8.85%), α-terpinolene (4.96%), α-humulene (4.10%), α-terpineol (2.83%), and p-cymene (2.33%). The extract showed antibacterial activity to E. coli, B. cereus, and S. aureus, with the reaction orders of 0.4460, 0.8235 and 0.6928, respectively.
... A number of different compounds were detected in the GC-MS analysis. Table 3 [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] shows the name of the compounds detected, their peak areas, type of metabolite and whether that type of metabolite had any previous record of antimicrobial activity. Fig. 3 shows the total chromatogram of the GC-MS. ...
... We tested the extract on a wide range of Gram-positive and Gram-negative isolates that causes various types of diseases. S. aureus is known to cause serious diseases such as pneumonia and Phenolic Report present as antimicrobial [28] KPC-producing bacteria is a new group of highly drug-resistant Gramnegative bacilli whose incidence is rapidly increasing throughout the globe. Infections caused by KPCenzyme (responsible for carbapenem resistance) producing K. pneumoniae have been associated with frequent treatment failures and death. ...
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In this study, antimicrobial property of Suaeda maritima, a mangrove associate species collected from lower Gangetic delta complex was evaluated. The antibacterial activity of the extract against a wide spectrum of Gram-negative and Gram-positive isolates and multiple antibiotic resistant strains suggested that it may be a potential antibacterial agent to control antibiotic resistant infections. Among the different solvent fractions examined, n-hexane extract of the shoot of S. maritima L (Dumort) was found to possess highest antibacterial activity against four Gram-positive (Bacillus subtilis, Staphylococcus haemolyticus, S. aureus, Enterococcus faecalis) and six Gram-negative (Escherichia coli, Citrobacter sp., Klebsiella pneumoniae, KPC producing K. Pneumonia, Pseudomonas sp. and Stenotrophomonas maltophila) bacteria. Fungicidal activity was noted against Saccharomyces cerevisiae. Minimum inhibitory concentration and minimum bactericidal concentration values were determined in disc diffusion and macrodilution assays. The inhibition zones ranged between 13-20 mm. Gas chromatography-mass spectrometry analysis of the n-hexane fraction showed the presence of various fatty acid esters and essential oils. In addition, scytalone known for its antioxidant property, campesterol and ethanone were detected. Antioxidant activity was found having an IC50 value of 52.53 mg/ml.
... Z, z-6,28-heptatriactontadien-2-one possesses vasodilatory properties (Mallikadevi et al., 2012). 1-heptacosanol is a long chain alcohol possessing antimicrobial and anti-oxidant properties (Al-Abd et al., 2015) which was found to be present in both n-hexane and chloroform extracts. However, the three crude extracts did not contain a common major compound in them. ...
... Z, z-6,28-heptatriactontadien-2-one possesses vasodilatory properties (Mallikadevi et al., 2012). 1-heptacosanol is a long chain alcohol possessing antimicrobial and anti-oxidant properties (Al-Abd et al., 2015) which was found to be present in both n-hexane and chloroform extracts. However, the three crude extracts did not contain a common major compound in them. ...
... Interestingly, our results were similar to that reported by Al-Abd et al., wherein M. cajuputi flower and leaf extracts were found to have a wide range of antimicrobial potential against Gram positive bacteria. 25 However, they did not observe inhibition zones against the Gram negative bacteria tested. The differences in these findings are probably due to the distinctive solvent types that were used to extract phytocomponents from plant materials. ...
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Melaleuca cajuputi Powell is a tree species belonging to the family Myrtaceae and is widely used in traditional medicine. This study was conducted to investigate the antibacterial activities of essential oils of M. cajuputi Powell. Antibacterial activity was tested against Gram positive and Gram negative bacteria using the agar disc diffusion method. The essential oils of M. cajuputi were found to exert antibacterial activity against all of the tested bacteria, including Staphylococcus aureus, Streptococcus pyogenes, methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae, and Escherichia coli. The zones of inhibition for S. aureus, S. pyogenes, MRSA, E. coli, and K. pneumoniae were 12.7 mm, 10.7 mm, 10.0 mm, 8.7 mm and 9.3 mm respectively, against 0.714% (w/w) of the essential oils. These results highlighted that Gram negative bacteria are less susceptible to the essential oils of M. cajuputi. A large zone of inhibition might be a sign of a leaching antimicrobial agent. These findings suggest that M. cajuputi is a potential natural antibacterial agent.
... In cell suspension extracts of Scrophularia kakudensis Franch, greater concentrations of MeJa substantially regulated the activities of antioxidant enzymes and increased the scavenging potentials of free radicals [42]. Furthermore, phenolic compounds can scavenge reactive oxygen intermediates without triggering further oxidative processes [43]. A previous study has revealed that TPC takes on different levels based on the Thymus species [38]. ...
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Thyme species are a good source of thymol and carvacrol, which plays a key role in controlling diseases. For the first time, the expression patterns of γ -terpinene synthase (TPS2), CYP71D178, and CYP71D180 genes and phenolics compounds amount were evaluated in T. migricus and T. daenensis after different methyl jasmonate (MeJA) treatments. The highest thymol and carvacrol contents were observed in T. migricus (86.27%) and T. daenensis (17.87%) at MeJA 100µM, which was consistent with the expression patterns of the three investigated genes. All species treated showed high total phenolic and flavonoid content compared to control plants for which the highest amounts were observed in T. vulgaris treated with 100 µM and 10 µM MeJA. Further-more, in the 100 µM MeJA treatment, the relative expression of TPS2 and CYP71D178 in T. mi-gricus increased 7.47 and 9.86-fold compared with the control, respectively. The highest level of CYP71D180 transcripts (5.15-fold) was also observed for T. daenensis treated. This finding highlights the notion that thymol was known as the dominant component of the essential oil rather than carvacrol in diffident thyme species. This implies that MeJA at different concentrations in-fluenced metabolic pathways, induced expression changes, resulting in a rise in essential oil lev-els.
... 1-Heptacosanol is a longchain primary fatty alcohol. As this compound has already been reported to have nematocidal, anticancer, antioxidant, and antimicrobial activities (30)(31)(32), some of the antimicrobial properties of M. sylvestris extract may be depend on the presence of 1-heptacosanol. Another most detected compound, 17-pentatriacontene, which has also been identified from the leaves extract of Eichhornia crassipes, indicated anti-inflammatory, anticancer, antibacterial, and antiarthritic properties (33). ...
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Background: Considering the increased rate of microbial resistance to antibiotics and chemical side effects of antibiotics, there is a need for an alternative antimicrobial agent with fewer complications. Medicinal plants are rich resources of phytochemical compounds with antibacterial activity that could fight off this problem. Objectives: The aim of this research was to investigate the chemical composition, antimicrobial, and antibiofilm properties of Malva sylvestris on some pathogenic bacteria. Methods: Antibacterial effect of the extract was assessed by the well diffusion and broth microdilution methods against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli. The anti-biofilm property of the extract was also examined using the crystal violet assay. Finally, the chemical constituents and total phenols of the extract were determined by gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC), respectively. Results: The methanolic extract of M. sylvestris showed antimicrobial activity against all tested Gram-negative and Gram-positive strains by the agar well diffusion method. The minimum inhibitory concentration (MIC) of the extract ranged from 21.9 ± 0.1 to 51.9 ± 0.5 mg/mL against the tested microorganisms. In addition, the minimum bactericidal concentration (MBC) spanned from 43.7 ± 0.1 to 85.8 ± 0.3 mg/mL. The biofilm inhibitory concentration (BIC50) of the extract was found to be 40 - 87 mg/mL against the tested bacteria. Analysis of the extract by GC-MS indicated that the most abundant compounds were 1-heptacosanol (38.41%), 17-Pentatriacontene (19.78%), and 6,9,12,15-docosatetraenoic acid, methyl ester (8.08%). High-performance liquid chromatography confirmed the presence of apigenin (6.84 ppm) and salicylic acid (1.5 ppm) as phenolic compounds in M. sylvestris methanolic extract. Conclusions: The results of this study represent the high potency of M. sylvestris extract as a source of biologically-active compounds for the development of future phytotherapeutic products with antibacterial and antibiofilm activity.
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Shrimp consumption has increased steadily around the world, as has the emergence of bacterial pathogens, which cause massive economic losses. The incorporation of plant extracts in aquatic animal feeds has been suggested to improve growth performance and resistance against bacterial pathogens. Therefore, the aim of this study was to evaluate the effects of Cajeput Melaleuca cajuputi leaf extract (MCLE) on the growth performance, physiological responses and resistance of Giant freshwater prawn Macrobrachium rosenbergii against Aeromonas hydrophila. The phytochemical composition of the MCLE was analysed using gas chromatography–mass spectrometry (GC‐MS). Thereafter, the MCLE was included in diets (0.0, 5.0, 10.0 and 15.0 g/kg) fed to the M. rosenbergii. The growth was observed after 45 days of the feeding trial, whereas physiological responses and clearance efficiency (%) against A. hydrophila were observed on the 60th day. 2‐Isopropyl‐10‐methylphenanthrene, phenanthrene, 1‐methyl‐7‐(1‐methyl ethyl) and 4H‐1‐Benzopyran‐4‐one, 3‐acetyl‐5, 7‐dihydroxy‐2‐methyl‐ compounds were detected as the major compounds in the MCLE. A significant improvement (p < 0.05) of growth and survival of M. rosenbergii fed with MCLE supplementation at 15.0 g/kg was observed. The total haemocyte count, hyaline cells and granular cells were also increased (p < 0.05) in the M. rosenbergii fed with diets included with MCLE. Upon challenging the primed M. rosenbergii with sub‐lethal doses of A. hydrophila, the highest clearance efficiency (73%) was achieved in the prawn‐fed 15.0 g/kg MCLE based diet (p < 0.05) after 96 h post injection. These findings indicate the potential of MCLE supplementation to improve growth, immune responses of M. rosenbergii and their resistance against A. hydrophila.
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An aqueous extract of Lemna minor (LE – 0.5%, dry weight/volume), a wild spontaneous aquatic species, was used as an active agent in poly (vinyl alcohol) (PVA) films at the concentrations of 1, 5, 10, 20 wt%, realized through the solvent casting process. This species was selected after determining a high total phenol content (TPC – 6.7 mg g⁻¹ DW) and antioxidant of its aqueous extract. Transparency, color and morphological studies were considered to define the effect of the LE component on the optical properties of the matrix obtained. In addition, antioxidant, antifungal and antibacterial studies were performed to shed light on the LE effect on the active functional properties of the realized films for multifunctional packaging. The optical characterization of the obtained films revealed that the extract of Lemna minor in PVA films induced some alterations, although its presence determined positive radical scavenging and antimicrobial activity. These results demonstrate the possibility of using these polymeric systems in the food packaging sector.
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Woodfordia fruticosa (L.) Kurz is a widely used plant in traditional medicine systems. The tribal communities of Amarkantak, Madhya Pradesh (India) are using this plant for the treatment of general weakness, blood related complications like blood deficiency, blood purification and for the treatment of symptoms related to sickle cell disease (SCD). SCD is a genetic disease with life threatening complications. In the absence of any drugs without any side effects, the alternative plant based therapies that may either reduce/ reverse the sickling of the red blood cells can be safe and effective therapeutic agents. We evaluated W. fruticosa extracts for phytoconstituents, anti-oxidant and anti-inflammatory properties. Anti-sickling properties of the extracts were evaluated by estimation of reverse sickling, polymerization inhibition and osmotic fragility assays. Chemical profiling of the methanol extract was done using LC-MS analysis. Phytochemicals such as alkaloids, steroids, tannin, and saponins were present in all the extracts. Methanol extract displayed maximum reversal (66±1%) of sickled Red blood Cells (RBC) and significantly inhibited Hb polymerization. The hexane and methanol extracts led to minimum hemolysis of sickled RBC in the osmotic fragility assays. Total tannin (365±2.4 TAE) content was highest in acetone extract, while the total flavonoid and phenolic content (156.9±2.0 QE) and (113.7±0.7 GAE) were highest in methanol extract. The methanol extract displayed minimum IC50 (8.1±1.5) in 2, 2-diphenylpicrylhydrazyl (DPPH) while the acetone extract had minimum IC50 (215.8±5.7) in 2,2'-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay. The hexane extract displayed maximum Ferric reducing anti-oxidant power (FRAP) value (1.5±0.5 mM Fe(II)/mg dry weight) that were higher than methanol and aqueous extracts (1.45±0.1, 1.45±0.05 mM Fe(II)/mg dry weight). The methanol extract provided maximum RBC protection from hemolysis (73.8±0.8%). Maximum Lipoxygenase (LOX) inhibition was observed by the acetone and methanol extracts at 400 μg/mL while the hexane extract displayed maximum Xanthine oxidase (XO) inhibition (57.0±0.5%). LC-MS profiling of the methanol extract identified several secondary metabolites that might be responsible for the observed activities. The results validate the traditional use of W. fruticosa and present us with potential compounds for further development of novel anti sickling agents.
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This article deals with the comparison of the antioxidant activity of aqueous extracts of various parts of Carica papaya L. The evaluation of total phenolic content and total flavonoid content revealed high antioxidant potential of the seeds and fruits. The free radical-scavenging potential of the aqueous extracts indicated the seeds to have better DPPH-scavenging activity than fruits. The results were augmented by the FRAP activity as well. The phenolics present in the extracts were separated and identified as 5-hydroxy feruloyl quinic acid, acetyl p-coumaryl quinic acid, quercetin-3-O-rhamnoside, syringic acid hexoside, 5-hydroxy caffeic quinic acid, peonidin-3-O-glucoside, sinapic acid-O-hexoside, cyaniding-3-O-glucose and methyl feruloyl glycoside by LCMS-MS technique.
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Background In the Indian ayurvedic system of medicine, Nymphaea nouchali is used for the treatment of diabetes, cutaneous diseases, inflammation, liver disorders, urinary disorders, menorrhagia, blenorrhagia, menstruation problem, as an aphrodisiac, and as a bitter tonic. However, despite its traditional usage as an antimicrobial agent, there is no information regarding its effectiveness in infections caused by pathogenic microbes. Hence, we evaluated 70% ethanol extract of the seeds of N. nouchali for its antimicrobial activity. Methods The antimicrobial activity of the extract at five different concentrations was tested against few common human pathogenic microorganisms by agar disc diffusion assay. The Minimum Inhibitory Concentration of the extract was determined by the modified resazurin method. Streptomycin (10 μg/ml) and amphotericin B (10 μg/ml) were used as standards for antibacterial and antifungal study respectively. Few phenolic compounds were identified and quantified by standard HPTLC technique. Results The zone of inhibition was extremely great for P. aeruginosa (25 mm), S. aureus (20 mm) and C. albicans (19 mm). MIC value was the least at 0.03 mg/ml for bacteria: K. pneumoniae, S. dysenteriae and E. coli and 0.31 mg/ml for fungi: C. albicans and T. mentagrophytes. Moreover, through HPTLC analysis few phenolic compounds were quantified, among which catechin content was found to be the highest (3.06%), followed by gallic acid (0.27%) and quercetin (0.04%). Conclusions The results therefore clearly indicates that the crude extract from N. nouchali seeds could be used as a potential source of natural antimicrobial agent owing to the presence of the phytoconstituent catechin in abundance along with other active compounds and supports the traditional use of the plant in the treatment of infections.
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Bamboo has the peculiarity of flowering and seeding only once after a long vegetative phase. Bamboo seeds of species Bambusa bambos are put into a variety of traditional medicinal uses and also an important source of food for indigenous people of Western Ghats of south India. Bamboo seeds lack evidence of scientific study and an attempt was made to identify the phytoconstituents present in it. Oil was isolated from aqueous ethanolic extract of bamboo seed for the first time. GC-MS characterization, in vitro antioxidant (DPPH, ABTS, Nitric oxide and alkaline DMSO methods) and antimicrobial screening were determined. In GC-MS analysis bamboo seeds oil showed the presence of 28 phytoconstituents includes long chain aliphatic carboxylic acids (saturated and unsaturated) and their derivatives including, aldehyde, esters and alcohols, as well as aromatic compounds, and a steroidal compound. Bamboo seed oil showed good antioxidant and antimicrobial activities.
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Squalene and tocopherols are the most important bioactive constituents in lipophilic amaranth fraction. Therefore, developments of processes of isolation of amaranth extracts enriched with these compounds are of interest. In this study the lipophilic fraction of amaranth seeds was extracted by supercritical fluid extraction with carbon dioxide (SCE-CO2) under different pressure conditions and by adding 2 and 5% of cosolvent ethanol. The yield of extract varied from 1.37 (15 MPa without cosolvent) to 5.12% (55 MPa and 5% of cosolvent). The highest content of unsaponifiables (21.1%) in the extract was at 55 MPa and 5% of cosolvent; at these conditions the yields of tocopherols and squalene from amaranth seeds were 317.3 mg/kg and 0.289 g/100 g, respectively. Tocopherol isomers in amaranth oil were distributed at the approximate ratio of 1(α-T):27(β-T):6.5(γ-T):5(δ-T). The extract was fractionated in the two separators by gradual decrease of the pressure and it was found that the fraction obtained at ambient conditions contained the highest concentration of tocopherols (up to 7.6 mg/g) and squalene (up to 17.9 g/100 g oil). The highest antioxidant activity measured by the L-ORAC assay possessed the fractions with the highest concentrations of squalene and tocopherols and obtained at 15 MPa with pure CO2 (235.1 μmol TE/g) and 2% of cosolvent (257.6 μmol TE/g).
Article
Hydrodistillation of cajuput (Melaleuca cajuputi) leaves collected from 6 sites in Narathiwat gave different yields of cajuput oils. The maximum oil yield (0.97%) was obtained from leaves from Ban Koke Kuwae, Thambon Kosit, and Amphur Tak Bai. The oil yields from leaf samples of other sites were 0.84% from Ban Pha Ye and Thambon Sungai Padi in Amphur Sungai Padi; 0.76% from Ban Lubosama, and Thambon Pasemat, in Amphur Sungai Kolok; 0.70% from Ban Tha Se, and Thambon Kosit, in Amphur Tak Bai; 0.66% from Ban Mai, and Thambon Sungai Padi, in Amphur Sungai Padi; and 0.56% from Ban Toh Daeng, and Thambon Phuyoh, in Amphur Sungai Kolok. Cajuput oil densities from the 2 sites of Amphur Sungai Kolok and from Ban Mai, Thambon Sungai Padi, Amphur Sungai Padi were almost the same, but higher than others. Although major components were not different, the minor components varied in terms of both structure and proportion. The major compositions of both cajuput oils from Ban Toh Daeng, Thambon Phuyoh, and Amphur Sungai Kolok consisted of 49.22% monoterpenes and 46.45% sesquiterpenes, and the rest were hydrocarbons and a diterpene. Other cajuput oils obtained composed mainly of monoterpenes (more than 62%), sesquiterpenes, hydrocarbons and some unknown compounds respectively. There was no diterpene present in these oils. Since cajuput oil was locally used as insecticide, termicidal activities of all oils were also investigated.