Comparative Evaluation of Antimicrobial Properties of Red and Yellow Rambutan Fruit Peel Extracts

Abstract

Background and Aims: Rambutan fruits are native to the humid tropical regions of the Peninsular Malaysia in Southeast Asia. Its antimicrobial properties are well known. There are two varieties of rambutan fruits available in Malaysian market ie red and yellow rambutan.
Methodology: In the present study, a qualitative phytochemical analysis along with antibacterial properties of methanolic extract of both the varieties of rambutan peels were carried out by disc diffusion method against Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa.
Results: The methanolic extract of yellow rambutan peels showed more potency than red rambutan peels against Streptococcus pyogenes and Staphylococcus aureus ranged from 7-10mm and 5-12mm, respectively in different concentrations. At the same time both the extracts do not showed zone of inhibition against Escherichia coli and Pseudomonas aeruginosa.
Conclusion: These results showed that methanolic extract of yellow rambutan peels are good candidate for further investigation against gram positive bacteria.

Full text

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*Corresponding author: Email: mahendransekar@rcmp.unikl.edu.my;
Annual Research & Review in Biology
4(24): 3869-3874, 2014
SCIENCEDOMAIN international
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Comparative Evaluation of Antimicrobial
Properties of Red and Yellow Rambutan Fruit
Peel Extracts
Mahendran Sekar1*, Fatin Nabila Aziz Jaffar1, Nur Hasyimah Zahari1,
NurIzzati Mokhtar1, Nurul Ain Zulkifli1,
Ramizatun Annisa Kamaruzaman1and Syafiq Abdullah1
1Faculty of Pharmacy and Health Sciences, Universiti Kuala Lumpur, Royal College of
Medicine Perak, Ipoh – 30450, Malaysia.
Authors’ contributions
This work was carried out in collaboration between all authors. Author MS designed the
study, wrote the protocol, and wrote the first draft of the manuscript. Authors FNAJ, NHZ,
NM, NAZ, RAK and SA managed the analyses of the data. All authors read and approved
the final manuscript.
Received 9th May 2014
Accepted 26th June 2014
Published 12th July 2014
ABSTRACT
Background and Aims: Rambutan fruits are native to the humid tropical regions of the
Peninsular Malaysia in Southeast Asia. Its antimicrobial properties are well known. There
are two varieties of rambutan fruits available in Malaysian market i.e. red and yellow
rambutan.
Methodology: In the present study, a qualitative phytochemical analysis along with
antibacterial properties of methanolic extract of both the varieties of rambutan peels were
carried out by disc diffusion method against Streptococcus pyogenes, Staphylococcus
aureus, Escherichia coli and Pseudomonas aeruginosa.
Results: The methanolic extract of yellow rambutan peels showed more potency than red
rambutan peels against Streptococcus pyogenes and Staphylococcus aureus ranged from
7-10mm and 5-12mm, respectively in different concentrations. At the same time both the
extracts do not showed zone of inhibition against Escherichia coli and Pseudomonas
aeruginosa.
Conclusion: These results showed that methanolic extract of yellow rambutan peels are
good candidate for further investigation against gram positive bacteria.
Short Research Article

Annual Research & Review in Biology, 4(24): 3869-3874, 2014
3870
Keywords: Nephelium lappaceum; red and yellow rambutan; antimicrobial.
1. INTRODUCTION
Nephelium lappaceum Linn., commonly known as rambutan which belongs to the family of
Sapindaceae, is an attractive tropical fruit widely distributed in South -East Asia, especially in
Malaysia and Indonesia [1]. It is a potential fruit to be commercialized since it is widely
planted all over Malaysia. Rambutan has been used as traditional medicine for centuries
especially as a remedy for diabetes and high blood pressure [2,3].
Rambutan contains a large variety of substances possessing antioxidant activity, such as
vitamin C, vitamin E, carotenes, xanthophylls, tannins and phenolics [4]. They also exhibit a
wide range of biological activities including antimicrobial, anticarcinogenic as well as
antiproliferative, and many other biological activities have been attributed to their antioxidant
properties [5].
Medicinal plants represent a rich source of antimicrobial agents. There is also an urgent
need to search for new antimicrobial compounds with novel mechanisms of action because
there has been an alarming increase in the incidence of new and re-emerging infectious
diseases [6]. A numeral commercial variety of rambutan (Nephelium lappaceum Linn.)
exists. In Malaysia, red and yellow rambutan fruits are available in the market. The fruits are
ovoid, with a red or yellow pericarp covered with soft spines that vary in colouring from
yellow and red. They are different in taste. However, so far there is no comparative study
have been reported in rambutan varieties, though various extracts of Nephelium lappaceum
have been reported for antibacterial activity [5,7]. Hence, in the present study, we aimed to
carry out a comparative investigation of antimicrobial properties of different varieties of
rambutan fruits using standard methods.
2. MATERIALS AND METHODS
2.1 Chemicals and Reagents
All the chemicals and reagents used were analytical grade.
2.2 Collection and Authentication of Plant Materials
The fruits of red and yellow rambutan (Fig.1, Nephelium lappaceum Linn.) were collected
from local market, Ipoh District, Perak, Malaysia and authenticated by botanist.
2.3 Extraction of Red and Yellow Rambutan Peels
The peels of red and yellow rambutan were removed from the fruit and washed thoroughly in
distilled water to remove contaminants; it was chopped into small pieces and dried under
shade, coarsely powdered and separately subjected to extraction by maceration in double
distilled methanol at room temperature with occasional shaking for seven days [8]. The
macerate extracts were filtered and the filtrate was dried at low temperature (40-50ºC) under
vacuum. The extracts were stored in air-tight containers in a refrigerator at 4ºC until further
use.

Annual Research & Review in Biology, 4(24): 3869-3874, 2014
3871
Fig. 1. Red and yellow rambutan fruits (Nephelium lappaceum Linn)
2.4 Qualitative Phytochemical Analysis
Qualitative phytochemical analysis of all the extracts were carried out by using various
chemical tests [9] to identify the phytoconstituents present in it
Tests for carbohydrates: Molisch’s test, Fehling’s test, Benedict’s test.
Tests for alkaloids: Mayer’s test, Dragendorff’s test, Wagner’s test.
Tests for steroids and sterols: Liebermann Burchard’s and Salkowski test.
Tests for glycosides: Baljet’s test, Borntrager’s test and Keller-Kiliani test.
Tests for saponins: Foam test and hemolysis test.
Test for flavonoids: Shinoda test.
Tests for tannins: Lead acetate test and gelatin test.
Test for triterpenoids: Tin and thionyl chloride test.
Tests for proteins and amino acids: Biuret test and Ninhydrin.
2.5 Antimicrobial Screening
2.5.1 Test microorganisms
A panel of four common pathogenic microorganisms were used in the study, which includes
gram-positive bacteria (Streptococcus pyogenes and Staphylococcus aureus), gram-
negative bacteria (Escherichia coli and Pseudomonas aeruginosa).
2.5.2 Disc-diffusion method
A suspension of the tested microorganisms was uniformly swabbed on agar. Sterile blank
discs were individually impregnated with different concentration of extracts (1000, 500,
250µg/ml) and placed onto the inoculated agar plates [6]. The plates were inverted and
incubated at 37ºC for 24h. The antimicrobial activity was measured by measuring diameter
of the resulting zone of inhibition against the tested organisms. The test for positive control
(Bacitracin, penicillin, cefriaxone and ciprofloxcin) and negative control (Methanol) were
performed in duplicate.

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3. RESULTS AND DISCUSSION
3.1 Nature and Yield of the Extracts
The nature of two varieties of rambutan peels extracts and yields are mentioned in Table 1.
The percentage yield of red rambutan peels extract (6.18%) was more than yellow rambutan
extract (4.72%).
Table 1. Yields and nature of methanolic extract of red and yellow rambutan peels
Plant source
Quantity used for methanol
extraction
Nature of the
extracts
Yield
(%)
Powder (g)
Solvent (ml)
Red Rambutan
50
300
Brownish semisolid
6.18
Yellow Rambutan
50
300
Yellowish semisolid
4.72
3.2 Qualitative Phytochemical Analysis
Phytochemical analysis (Table 2) of crude methanolic extracts of red and yellow rambutan
peels showed the presence of carbohydrates, proteins, aminoacids, steroids, flavonoids,
tannins, triterpenoids and fixed oils. Both the extracts showed the presence of same
constituents qualitatively and this may be different from quantitatively.
3.3 Antimicrobial Activity
In the present study we have been used methanol for extraction of rambutan peels which
may contain higher amount of polar and phenolic compounds. The antibacterial activity of
crude methanolic extract of red and yellow rambutan peels against Streptococcus pyogenes,
Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were presented in
Table 3. The zone of inhibition produced by the crude methanolic extract of red rambutan
peels against Streptococcus pyogenes and Staphylococcus aureus were 7mm and 5-10mm,
respectively in different concentrations.
The methanolic extract of yellow rambutan peels showed more potency than red rambutan
peels against Streptococcus pyogenes and Staphylococcus aureus ranged from 7-10mm
and 5-12mm, respectively in different concentrations. At the same time both the extracts do
not showed zone of inhibition against Escherichia coli and Pseudomonas aeruginosa.
However, the standards showed better activity with lower concentration when compared to
both the extracts against the tested organisms.
The results indicate that the methonolic extract of red and yellow rambutan peels showed
antibacterial activity toward only in gram positive ( Streptococcus pyogenes and
Streptococcus aureus) not in gram negative bacteria (Escherichia coli and Pseudomonas
aeruginosa). The methanolic extracts of yellow rambutan peels showed more effective result
than red rambutan peels extract against gram positive bacterial strains. The highest anti
bacterial activity was recorded in both the extracts against Staphylococcus aureus.

Annual Research & Review in Biology, 4(24): 3869-3874, 2014
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Table 2. Qualitative phytochemical analysis of methanolic extract of red and yellow
rambutan peels
Phytoconstituents
Methanolic extract of red
rambutan peels
Methanolic extract of yellow
rambutan peels
Alkaloids
-
-
Carbohydrates
+
+
Proteins
+
+
Aminoacids
+
+
Steroids and sterols
+
+
Glycosides
-
-
Flavonoids
+
+
Tannins
+
+
Triterpenoids
+
+
Fixed oils
+
+
+ Present, - Absent
Table 3. Antimicrobial activity of methanolic extract of red and yellow rambutan peels
S. No.
Organism used
Concentration in µg/ml
Control
Standard
Methanolic extract
of Red rambutan
peels
Methanolic extract
of Yellow rambutan
peels
1000
500
250
1000
500
250
Gram positive bacteria
1
Streptococcus
pyogenes
7
mm
-
-
10
mm
7
mm
-
-
Bacitracin
(4µg/ml, 25
mm)
2
Staphylococcus
aureus
10
mm
8
mm
5
mm
12
mm
10
mm
5
mm
-
Penicillin
(10µg/ml,
28 mm)
Gram negative bacteria
3
Escherichia coli
-
-
-
-
-
-
-
Cefriaxone
(30µg/ml,
26 mm)
4
Pseudomonas
aeruginosa
-
-
-
-
-
-
-
Ciprofloxcin
(5µg/ml, 21
mm)
-No inhibition
These findings are supported by the reported results of earlier study [3,5]. The results of this
study reflect that potent phytochemicals are present in the methanolic extract of yellow
rambutan peels than red rambutan peels quantitativey and not in qualitatively. The crude
methanolic extract of yellow rambutan peels was biologically active when compared to red
rambutan peels.
4. CONCLUSION
In conclusion, the above results showed that methanolic extract of yellow rambutan peels
are good candidate for further investigation against gram positive bacteria. Furthermore, the
isolation of active constituents which are responsible for the activity is necessary for broad
investigation.

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3874
COMPETING INTERESTS
Authors have declared that no competing interests exist.
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