Der Pharma Chemica, 2014, 6(3):256-260
Chemical constituents of Syzygium samarangense
Consolacion Y. Ragasa
, Francisco C. Franco Jr.
, Dennis D. Raga
and Chien-Chang Shen
Keywords: Syzygium samarangense,
cycloartenyl stearate, lupenyl stearate, β -sitosteryl stearate, 24-
Syzygium samarangense (syn. Eugenia javanica Linn.) commonly known as ‘makopa’ is grown throughout the
Philippines for its fruits. The tree is used as an antipyretic and a diuretic 
. Four flavonoids isolated from the
hexane extract of S. samarangense showed dose-dependent spasmolytic activity . Another study reported that
from S. samarangense exhibited significant differential
cytotoxicity against the MCF-7 cell line and significant selective cytotoxicity against RAD 52 yeast mutant strain
. Compounds isolated from the hexane extract of the leaves of S.
-carotene, lupeol, betulin,
extract of makopa leaves exhibited high antidiabetic activity , while a recent study reported that
-desmethoxy matteucinol from S. samarangense significantly
diabetic mice . Recently, we reported the potent analgesic and anti-inflammatory activities and the negligible
toxicity on zebrafish embryonic tissues of a mixture of
cycloartenyl stearate (8a), lupenyl stearate (8b), sitosteryl
stearate (8c), and 24-
stearate (8d) from the dichloromethane extract of the air-dried leaves of
S. samarangense .
We report herein the isolation and identification of 2
betulin (5), lupeol (6), sitosterol (7), and a mixture of cycloartenyl stearate (8a), lupenyl stearate (8b), β-sitosteryl
stearate (8d) (Fig.1) from the air-dried leaves of S. samarangense. To
the best of our knowledge this is the first report on the isolation of 8a-8d from the tree. Results of the hypoglycemic
and antimicrobial tests on a mixture of 8a-8d are likewise reported.
8 b R = C H
2 R = O H , R ' = C H
3 R = O C H
, R ' = H
O C H
8 c R = C H
8 a R = C H
8 d R = C H
(3), squalene (4), betulin (5), lupeol (6), sitosterol (7), cycloartenyl
stearate (8a), lupenyl stearate (8b), β-sitosteryl stearate (8c), and 24-
MATERIALS AND METHODS
General Experimental Procedures
NMR spectra were recorded on a Varian VNMRS spectrometer in CDCl
at 600 MHz for
H NMR and 150 MHz
C NMR spectra. 2D NMR (COSY, HSQC, HMBC) spectra were recorded on a Varian VNMRS spectrometer.
gel 60 (70-230 mesh); TLC was performed with plastic backed plates coated with silica gel F
; plates were
Fresh leaves of Syzygium samarangense (5 kg) were collected from Antipolo City in December 2008. Specimens of
the sample were authenticated at the Institute of Biology, University of the Philippines, Diliman, Quezon City. A
voucher specimen # 140 was deposited at the Chemistry Department, De La Salle University-Manila.
The air-dried leaves of Syzygium samarangense (1 kg) were ground in an osterizer, soaked in CH
for three days
and then filtered. The filtrate was concentrated under vacuum to afford a crude extract (45.86 g) which was
chromatographed in increasing volumes of acetone in CH
and 10 % acetone in
fractions were combined and rechromatographed in petroleum ether. The less polar fractions afforded 4 (55
mg). The more polar fractions were rechromatographed in increasing percentage of EtOAc in petroleum ether
(0.5%, 1%, 2.5% and 5% by volume) to afford sample 8 which is a mixture of 8a-8d (1g). The 20% and 30%
acetone in CH
fractions were combined and rechromatographed (5 ×) in CH
mg). The 40% and 50% acetone in CH
rechromatographed (6 ×) in CH
The microorganisms used were obtained from the University of the Philippines Culture Collection (UPCC). These
are Pseudomonas aeruginosa (UPCC 1244), Bacillus subtilis (UPCC 1149), Escherichia coli (UPCC 1195),
and Aspergillus niger (UPCC 3701). Sample 8 was tested for antimicrobial activity against these microorganisms
using the procedure reported in the literature .
A total of 50 male albino mice (Mus musculus L.) of an inbred ICR strain (7 weeks old) weighing 19.0 ±2.0 g were
acclimatized for 7 days prior to conducting the bioassay. The animals (n = 9) were procured from the Food and
Drugs Authority, Muntinlupa City, Philippines and housed at the animal containment unit of DLSU-Manila with
12h daylight and 12h darkness with free access to food pellets and water. A 16h fasting period was carried out prior
to each treatment procedure . All animal handling procedures were in accordance with the existing policies and
guidelines of the Philippine Association of Laboratory Animal Science (PALAS) for care and use of laboratory
animals and with Administrative Order 40 of the Bureau of Animal Industry relative to the Rep. Act. No.8485.
The anti-diabetes assay was performed modified from the procedure . Oral Glucose Tolerance Test (5 g/kg BW)
was performed on normoglycemic mice, followed by measurement of blood glucose level (mg/dL) using OneTouch
Horizon Glucometer (Lifescan, Johnson & Johnson, USA). Polysorbate 80 (25 mg/kg BW, Tween-80, AJAX,
Finechem Pty. Ltd., Australia) as the negative control for sample 8 (8a-8d). Solosa (16.7
g/kg BW, Glimepiride
O was orally administered as the positive control, while sample 8
Blood glucose was measured within a 3h period at 30 minutes intervals. Blood glucose reduction was computed as
percent reduction ([initial blood glucose – final blood glucose] / initial x 100) and was used in the statistical
Silica gel chromatography of the dichloromethane extract of the air-dried leaves of S. samarangense afforded 2
cycloartenyl stearate (8a), lupenyl stearate (8b), β-sitosteryl stearate (8c), and 24-
The structures of 1, 2, 3, 5 and 7 were elucidated by extensive 1D and 2D NMR analyses and confirmed by
comparison of their
C NMR data with those of 2
-methylchalcone , 2
H NMR data
NMR data with those of
The structures of 8a-8d were elucidated by extensive 1D and 2D NMR spectroscopy. The resonances attributed to
Confirmatory evidences are the
NMR data of
cycloartenyl acetate  for the triterpene part and the fatty acid ester of 16-
hydroxycycloartenyl palmitate  for the fatty acid part, which match in all essential respects. The fatty acid chain
length was determined by the mass spectrum of sample 8 which gave a molecular ion at m/z = 694.2 corresponding
to the molecular formula of C
] of m/z 409 which resulted from the loss of stearic acid
from the molecular ion peak. The resonances assigned to 8b indicated that it is lupenyl stearate , while
sitosteryl stearate .
On the other hand, 8d is
methylenecycloratenyl stearate as confirmed by similar
NMR data with
hydroxycycloartenyl palmitate  for the fatty acid part.
As part of our continuing search for antimicrobial compounds from Philippine medicinal plants, sample 8 was tested
is moderately active against the fungus, C. albicans with an activity index (AI = 0.3), slightly active against the
fungus, T. mentagrophytes (AI = 0.3), slightly active against the bacteria: E. coli (AI = 0.1), P. aeruginosa (0.3) and
S. aureus (AI = 0.1). It was inactive against B. subtilis and A. niger.
Table 1. Antimicrobial Test Results on Sample 8
Activity Index (AI)
An earlier study reported that the methanol extract of the leaves of makopa exhibited high antidiabetes activity .
activity where 2 significantly lowered the blood glucose levels of alloxan diabetic mice 
. Since 8a-8d were
obtained for the first time from S. samarangense and the leaves are known to have antidiabetes property, sample 8
was tested for hypoglycemic potential.
Solosa® or P80 as experimental, positive and negative controls, respectively. Blood glucose was measured 30
minutes after oral gavage and after every 30 minutes for 3h. Percent blood glucose reduction was found highest in
mice administered with 50 mg/kg BW sample 8 at 0.5h (Table 2). This observed reduction however is statistically
similar with the negative control and 100 mg/kg BW. This implies that there was minimal blood glucose reduction
as affected by the treatment. The effect however was very minimal that it is not possible to statistically identify it
from the effects of the negative control. Glimipiride Solosa on the other hand was found to have its effects at 1.0h
similar to our previous reports . Although the observed blood glucose reduction at 0.5
dosages of the treatment groups but rather to the net effects of insulin. The results however revealed no
hypoglycemic potential of sample 8.
25 mg/Kg BW
50 mg/Kg BW
100 mg/Kg BW
The results were analyzed using SPSS ver. 10.5 for windows. One way Analysis of Variance was performed to
determine the significant effects on anti-diabetic potentials of sample 8. Significant differences within group
variables were determined by post hoc analysis at 95% DMRT. Results were considered significant at
The data was presented as Mean±SD.
The antimicrobial tests were conducted at the University of the Philippines-Natural Sciences Research Institute (UP-
NSRI). A research grant from the De La Salle University Science Foundation through the University Research
Coordination Office is gratefully acknowledged.
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