Antibacterial Compounds from Propolis of Tetragonula laeviceps and Tetrigona melanoleuca (Hymenoptera: Apidae) from Thailand
Antibacterial Compounds from Propolis of Tetragonula laeviceps and Tetrigona melanoleuca (Hymenoptera: Apidae) from Thailand
Sirikarn Sanpa 0 1
Milena Popova 0 1
Vassya Bankova 0 1
Tawee Tunkasiri 0 1
Sukum Eitssayeam 0 1
Panuwan Chantawannakul 0 1
0 1 The Graduate School, Chiang Mai University , Chiang Mai , Thailand , 2 Department of Biology, Faculty of Science, Chiang Mai University , Chiang Mai , Thailand , 3 Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences , Sofia , Bulgaria , 4 Department of Physics, Faculty of Science, Chiang Mai University , Chiang Mai , Thailand
1 Academic Editor: Horacio Bach, University of British Columbia , CANADA
This study investigated the chemical composition and antimicrobial activity of propolis collected from two stingless bee species Tetragonula laeviceps and Tetrigona melanoleuca (Hymenoptera: Apidae). Six xanthones, one triterpene and one lignane were isolated from Tetragonula laeviceps propolis. Triterpenes were the main constituents in T. melanoleuca propolis. The ethanol extract and isolated compounds from T. laeviceps propolis showed a higher antibacterial activity than those of T. melanoleuca propolis as the constituent -mangostin exhibited the strongest activity. Xanthones were found in propolis for the first time; Garcinia mangostana (Mangosteen) was the most probable plant source. In addition, this is the first report on the chemical composition and bioactivity of propolis from T. melanoleuca.
Competing Interests: The authors have declared
that no competing interests exist.
Propolis is a resinous material collected by bees from various plant exudates. Bees use propolis
to narrow the nest entrances, seal cracks and embalm dead organisms inside the hive. The
antibiotic properties of propolis provide a healthy hive environment for the honeybee colony.
Propolis is an apicultural product that has been used for its biological properties, as an
alternative medicine and for disease prevention, in different parts of the world. The chemical
composition of propolis depends on the collection site, available plant sources and bee species , .
Several species of bees produce propolis, including Apis mellifera and stingless bees
(Meliponini) , .
Stingless bees are widespread over tropical and some subtropical regions of the world ,
. They are the major visitors of many flowering plants in the tropics. Propolis from stingless
bees is well known for its therapeutic properties, including antimicrobial, antitumor and
antioxidant activities , . In Thailand, Tetragonula laeviceps is widely distributed and
important because it is kept by local population and produces a large amount of propolis .
Research on the composition and biological activities of native Thai stingless bee propolis is
scarce, although information on its chemical composition and bioactive compounds would be
highly beneficial. This study investigated the chemical composition and antimicrobial activity
of propolis of two native Thai stingless bee species, Tetragonula laeviceps and Tetrigona
melanoleuca. Here we report, for the first time, information about T. melanoleuca propolis.
Materials and Methods
No specific permits were required for the described field studies. All field work was conducted
on private land and with owner permission. The field studies did not involve endangered or
Three Tetragonula laeviceps propolis samples were collected from Trat Province in eastern
Thailand (12 210 N, 102 250 E) in December 2009. The Tetrigona melanoleuca propolis
sample was collected from Chiang Mai Province in northern Thailand (18 480 N, 98 570 E) in
February 2012. The propolis samples were collected from honeypots and scraping from the nests.
Propolis samples (three of Tetragonula laeviceps and one of Tetrigona melanoleuca) were
extracted with 70% ethanol (1:10, w/v) at room temperature for 24 h (3 times). (see supplement
S1 Fig). The propolis extracts were evaporated to dryness and silylated using
N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA). Five milligrams of dry ethanol extract were mixed
with 50 l of dry pyridine and 75 l of BSTFA, heated at 80C for 20 min and analyzed by GC/
MS. The GC/MS analysis was performed with a Hewlett Packard Gas Chromatograph 5890
Series II Plus linked to a Hewlett Packard 5972 mass spectrometer system equipped with a 23 m
long, 0.25 mm id and 0.5 m film thickness HP5-MS capillary column. The temperature was
programmed from 100 to 310C at a rate of 5C/min. Helium was used as the carrier gas with a
flow rate 0.7 ml/min, split ratio of 1:80, injector temperature of 280C and ionization voltage of
Extraction and isolation
NMR spectra: 1H NMR (600 MHz) and 13C NMR (150 MHz), Bruker AV 600. The NMR
solvents are indicated in the Supplementary files together with the corresponding MNR spectra.
Tetragonula laeviceps propolis. Tetragonula laeviceps propolis (200 g) was extracted with
70% ethanol (1:10, w/v) at room temperature for 24 h (3 times) (see supplement S1 Fig). The
ethanol extract was concentrated under vacuum until has a volume of 3 L (approximately) and
extracted successively with petroleum ether (3 times) and ethyl acetate (3 times). The extracts
obtained were evaporated to give 5 g PE and 6.6 g EtOAc dry residue. A part of PE extract (4.5
g) was subjected to column chromatography with silica gel using a PEEtOAc gradient system
to give 22 fractions (A-V). Fraction L (25% PEEtOAc elute, 40 mg) was subjected to
preparative TLC (mobile phase PEEtOAc 7:4) to obtain -mangostin 1 (2 mg) . Fractions F and
G were combined (186 mg) and subjected to Lobar LiChroprep Si 60 Merck column (40
63 m) with a PEEtOAc gradient system to give 26 fractions (F01-F26). Fractions F09, F11
and F14 gave mangostanin 2 (4.9 mg) , 8-deoxygartanin 3 (4.6 mg)  and gartanin 4
(2.8 mg) , respectively. Fraction F21 (10% EtOAc elute, 20 mg) was subjected to
preparative TLC (mobile phase PEEtOAc 9:1, three-fold development) to obtain dipterocarpol 5
(4.7 mg) . Fraction U (10% EtOAc elute, 38 mg) was subjected to preparative TLC (mobile
phase CHCl3MeOH 15:1) to obtain -mangostin 6 (1.4 mg) . A part of ethyl acetate
extract (4.9 g) was extracted with CHCl3 (3 times) and evaporated to give 2.5 g dry residue. The
CHCl3 extract was subjected to silica gel column chromatography with a CHCl3EtOAc
gradient system to give 21 fractions (0121). Fractions 05, 07 and 08 were combined (210 mg) and
subjected to Lobar LiChroprep Si 60 Merck column (4063 m) with a CHCl3EtOAc
gradient system to give 14 fractions (05010514). Fraction 0501 gave garcinone B 7 (2.3 mg) .
Fraction 0512 (10% EtOAc elute, 13.5 mg) was subjected to preparative TLC (mobile phase
CHCl3EtOAc 7:3) to obtain methylpinoresinol 8 (4.7 mg) .
Tetrigona melanoleuca propolis. Tetrigona melanoleuca propolis (370 g) was extracted
with 70% ethanol (1:10, w/v) at room temperature for 24 h (3 times) (see supplement S1 Fig).
The ethanol extract was concentrated under vacuum until has a volume of 3 L
(approximately) and extracted successively with petroleum ether (2 times). The petroleum ether extract was
evaporated to give 32 g dry residue. A part of PE extract (20 g) was subjected to column
chromatography on silica gel with a PECH2Cl2 gradient system to give 21 fractions (A-U).
Fraction J, K and L (30% CH2Cl2 elute, 1.3 g) was re-chromatographed on silica gel with a PE
EtOAc gradient system to give 22 fractions (J1J22). Fraction J12 (11% EtOAc elute, 20 mg)
was subjected to preparative TLC (mobile phase PEEtOAc 8:2) to obtain a mixture of
ursolic and oleanolic aldehydes, 9 and 10 (14.3 mg) , . Fraction J13 (190 mg) was subjected
to Lobar LiChroprep Si 60 Merck column (4063 m) with a PEEtOAc gradient system to
give 11 fractions (J1301-J1311). Fraction J1308 (4% EtOAc elute, 20 mg) was subjected to
preparative TLC (mobile phase PEEtOAc 8:2) to obtain dipterocarpol 5 (12.5 mg) .
Fraction T from the PE extract (100% EtOAc elute, 2.2 g) was re-chromatographed on silica gel
with a PEEtOAc gradient system to give 12 fractions (T01-T12). Fraction T05 (194 mg) was
subjected to Lobar LiChroprep Si 60 Merck column (4063 m) with a PEEtOAc gradient
system to give 22 fractions (T0501-T0522) and fraction T0504 gave 3-O-acetyl ursolic acid 11
(5.6 mg) . Fraction T0513 (4% EtOAc elute, 20 mg) was subjected to preparative TLC
(mobile phase PEEtOAc 8:2) to obtain ocotillone I 12 (5.5 mg) . Fraction T0515 (4%
EtOAc elute, 20 mg) was subjected to preparative TLC (mobile phase PEEtOAc 8:2) to
obtain ocotillone II 13 (4.8 mg) . Fraction T10 was purified on silica gel column with a
CHCl3EtOAc gradient system to give a mixture of cabralealactone and isocabralealactone,
14 and 15 (2.9 mg) , .
All structures were elucidated using NMR (1D and 2D) spectral data (S2S14 Figs) and
compared with the literature.
The antibacterial activity of propolis ethanolic extracts and isolated compounds were
investigated. The antibacterial assay was determined by dilution method, measuring the minimal
inhibitory concentration (MIC) value in a 96-well microtiter plate . Eleven test
microorganisms; Listeria monocytogenes DMST 17303, Micrococcus luteus DMST 15503, Pseudomonas
aeruginosa ATCC 9027, Staphylococcus epidermidis DMST 15505, Streptococcus pyogenes
DMST 17020, methicillin-resistant Staphylococcus aureus (MRSA) DMST 20625, Serratia
marcescens DMST 21632, Salmonella typhimurium DMST 562, Bacillus cereus TISTR 687,
Escherichia coli ATCC 25922 and S. aureus TISTR 517 were used to test antimicrobial activity. All
isolated compounds were dissolved by Dimethyl Sulfoxide (DMSO) for the antimicrobial test.
Tested bacteria were cultured in Mueller Hinton broth (MHB) and incubated at 37C for 24
hours. Bacteria were suspended in MHB by adjusting to 0.5 McFarland, yielding a final density
of 108 cfu/ml. The ethanol extracts of propolis were prepared in concentrations ranging from
0.25 mg/ml to 128 mg/ml. In addition, pure compounds were prepared in concentrations
ranging from 0.39 g/ml to 25 g/ml for this assay. The two fold serial dilutions of propolis extract
or isolated compounds (180 l) and test strain solution (20 l) were added into each well of the
microtiter plate (Cell Culture Plates, metric volume 0.36 ml). Positive (broth and inoculum)
and negative (sterile broth) growth controls were used to compare. The MICs were determined
as the lowest concentrations of compounds preventing visible bacteria growth. The minimum
bactericidal concentrations were determined by subculturing 10 l of inoculum from the MIC
wells onto Mueller Hinton agar plates. The MBCs were determined as the lowest concentration
that prevented visible growth of bacteria subcultures on the agar plate. Each sample was tested
in triplicate. Gentamicin was used as positive control. The MICs and MBCs of gentamicin
ranged from 0.020.78 mg/ml and 0.021.56 mg/ml, respectively.
Statistical significance was evaluated using one way analysis of variance (ANOVA) by SPSS
version 16 (SPSS Inc.).
Results and Discussion
The chemical profiles of propolis ethanol extracts were studied by GC-MS (after silylation). All
three samples of T. laeviceps propolis displayed identical profiles, while T. melanoleuca propolis
was different from them (Total Ion Chromatograms: S15 Fig). Moreover, the GC-MS profiles
for propolis of both species did not coincide with any known propolis type and demonstrated
the lack of plant secondary metabolites previously found in propolis. For this reason, it was
necessary to isolate and identify individual compounds in order to reveal the specific chemistry
and, if possible, the plant origin of the studied stingless bee propolis.
The petrol ether fraction of the ethanol extract of T. laeviceps propolis was subjected to
repeated chromatographic separation and six individual compounds were isolated and
characterized (Fig 1), among which the prenylated xanthones: -mangostin 1, mangostanin 2,
8-deoxygartanin 3, gartanin 4, -mangostin 6 and the dammarane triterpene dipterocarpol 5. From the
ethyl acetate fraction of the ethanol extract, a further xanthone garcinone B 7 and the furofurane
lignane methylpinoresinol 8 were also isolated and identified. It is important to note that the
xanthones are new propolis constituents and the first xanthones to be isolated from the propolis.
Prenylated xanthones have been recognized as major secondary metabolites of Garcinia
mangostana (Mangosteen), and all the xanthones (14, 6, 7) have been previously isolated from the
pericarp and young fruit of mangosteen , , . As it is well known that bees collect
resinous material from the surfaces of young leaves, fruits and buds, G. mangostana is the most
probable plant source of T. laeviceps propolis. The mangosteen trees are widespread across
India, Myanmar, Malaysia, the Philippines, Sri Lanka and Thailand. The pericarp has been used
in Thai indigenous medicine for the treatment of trauma, diarrhea and skin infections for a long
time , . Previous studies have demonstrated antibacterial activity of xanthones and
extracts obtained from Mangosteen .
From petrol ether fraction of the ethanol extract of T. melanoleuca propolis, the triterpenes
3-O-acetyl ursolic acid 11, dipterocarpol 5, ocotillone I 12, ocotillone II 13, and two mixtures:
of ursolic and oleanolic aldehydes 910, and of cabralealactones 1415, were isolated after
repeated chromatographic procedures. Their structures were confirmed by comparison of their
NMR spectra with literature data. (S10S14 Figs) All of these triterpenes are new propolis
Fig 1. Compounds isolated from of Tetragonula laeviceps propolis. -mangostin 1, mangostanin 2,
8-deoxygartanin 3, gartanin 4, -mangostin 6 and garcinone B 7. The dammarane triterpene dipterocarpol 5
and the furofurane lignane methylpinoresinol 8 were isolated from T. laeviceps propolis.
constituents (Fig 2). Their presence in this propolis provides valuable chemotaxonomic
information about the plants from which the stingless bees T. melanoleuca collected resin. The
simultaneous occurrence of dammarane (5, 1215), ursane and oleanane derivatives (9, 10) has
been described as an indicator of the presence of dammar in the mixture . Dammar is a
triterpenic resin produced by trees belonging to the family Dipterocarpaceae. Dammar was
reported to possess antiviral activities and to be protective against in vitro low density lipoprotein
(LDL) oxidation .
A further confirmation of origin of T. melanoleuca propolis from dammar resin was the
identification in its GC-MS profile of other known dammar components:
2,3-dihydroxyolean12-en-28-oic (maslinic) acid and 2,3-dihydroxyurs-12-en-28-oic (corosolic) acid were
identified by comparison of the spectra of their silylated derivatives (S16 Fig) with literature data
. Two other acids were tentatively identified as 2,3-dihydroxyoleanadien-28-oic acid and
2,3-dihydroxyursadien-28-oic acid, based on comparison of the mass spectra of their TMS
derivatives (S17 Fig) with the mass spectra of underivatized 2,3-dihydroxyoleanadien-28-oic acid
and 2,3-dihydroxyursadien-28-oic acid , mass spectra of 2,3-diacetyloxyoleanadien-28-oic
acid and 2,3-diacetyloxyursadien-28-oic acid  and mass spectra of silylated maslinic and
corosolic acids . The major peak in the TIC chromatogram (23% of TIC) belonged to
2,3-dihydroxyursadien-28-oic acid and this is characteristic for the specific chemical profile of
Dipterocarpaceae resins, which has been previously demonstrated by Burger et al. .
Actually, different stingless bee species are known to collect resin from dipterocarp trees ;
stingless bees are even called dammar bees in some parts of India . Nonetheless, the reported
triterpenes (5, 915) have not previously been found in stingless bee propolis.
Fig 2. Compounds isolated from of Tetrigona melanoleuca propolis. 3-O-acetyl ursolic acid 11,
dipterocarpol 5, ocotillone I 12, ocotillone II 13, and mixtures of ursolic and oleanolic aldehydes 910, and
cabralealactones 1415 were isolated from T. melanoleuca propolis.
Antimicrobial activity of extracts and isolated compounds
The antimicrobial activity of ethanol extract of T. laeviceps propolis and T. melanoleuca
propolis samples was investigated. Eleven bacteria strains were used to test the minimal inhibitory
concentration (MIC) and the minimum bactericidal concentration (MBC). The ethanol extract
of T. laeviceps propolis displayed mild antimicrobial activity against S. epidermidis (MIC = 0.13
mg/ml; MBC = 32 mg/ml). The MICs and MBCs of T. laeviceps propolis ranged from 0.1316
mg/ml and 1128 mg/ml, respectively. The results for the total extract of T. laeviceps propolis
against S. aureus (MIC = 1 mg/ml; MBC = 16 mg/ml) are of the same order of magnitude as
the published by Kaewmuangmoon et al. (2012) . The ethanol extract of T. melanoleuca
propolis suppressed the development of S. aureus, methicillin-resistant Staphylococcus aureus
and E. coli. The MICs and MBCs ranged from 216 mg/ml and 16128 mg/ml, respectively. In
general, the MIC of the total extracts were close to or above the value of 1 mg/ml, accepted as
the highest relevant value in studies of the antibacterial activity of natural product extracts 
The results demonstrated that, of all tested organisms, S. epidermidis was the most sensitive
and S. marcescens the least sensitive (MIC = 16 mg/ml; MBC = 128 mg/ml). As can be seen,
propolis displayed both bacteriostatic and bactericidal actions depending on the concentration,
type of propolis, type of bacteria tested and methodologies to determine antimicrobial activity
. The ethanol extract of propolis from T. melanoleuca showed less activity against tested
microorganism compared with T. laeviceps.
Minimal Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of purified compounds from Tetragonula laeviceps against
pathogenic bacteria. B.c.; Bacillus cereus, L.m.; Listeria monocytogenes, M.l.; Micrococcus luteus, S.a.; Staphylococcus aureus, S.e.; Staphylococcus
epidermidis, S.p.; Streptococcus pyogenes, MRSA; methicillin-resistant Staphylococcus aureus, E.c.; Escherichia coli, P.a.; Pseudomonas aeruginosa, S.
t.; Salmonella typhimurium, S.m.; Serratia marcescens.
a,b,c,d,e Means with different letters are significant differences for purified compounds.
Furthermore, in search of the active principles, isolated pure compounds from both propolis
types were tested for their antibacterial activity against several bacteria. The constituents of T.
laeviceps propolis showed good activity (Table 1), especially against S. pyogenes (MIC = 0.78
25 g/ml; MBC = 1.3025 g/ml), followed by L. monocytogenes (MIC = 0.7825 g/ml; MBC
= >25 g/ml). Concerning statistical analysis results, -mangostin 1 was the most important
antibacterial compound among the eight active compounds identified in the T. laeviceps
propolis samples (p < 0.05). It is well known that the mangostins 1 and 6 are the major bioactive
compounds in the mangosteen . The antibacterial activities of T. laeviceps propolis extract
could be attributed to the xanthones, especially 1 and 6.
The triterpenes isolated from T. melanoleuca propolis exhibited MIC 25 g/mL against both
Gram-positive and Gramm-negative bacteria. The only exception was the mixture of oleanolic
and ursolic aldehides (9 and 10) with MIC 6.35 g/mL against S. aureus. Previous studies have
reported the antibacterial activity of these two compounds , . The MBC were over
25 g/mL in all cases, only 25 g/mL for ocotillone I, ocotillone II and the mixture of
cabralealactones against S. aureus.
The results of our study have revealed new data about the chemical composition and plant
origin of stingless bee propolis from Thailand. They indicate for the first time the plant source,
based on taxonomic markers, of the T. laeviceps propolis in Trat Province: the mangosteen
Garcinia mangostana. They also indicated for the first time, based on our chemical study of T.
melanoleuca propolis, that these stingless bees collect resin from dipterocarp trees. The
antibacterial tests demonstrated some potential of the propolis extract from T. laeviceps against S.
epidermidis, confirming its use in traditional medicine. The antibacterial activity of individual
constituents of the studied propolis has also been proved.
S2 Fig. 1H, 13C, DEPT, HSQC and HMBC NMR spectra of -mangostin 1 in acetone-d6.
S9 Fig. 1H, 13C, DEPT, HSQC and HMBC NMR spectra of methylpinoresinol 8 in CDCL3.
S17 Fig. Mass spectra of silylated 2,3-dihydroxyoleanadien-28-oic and
2,3-dihydroxyursadien-28-oic acids (from GC-MS of sample T. melanoleuca).
The authors wish to thank Dr. Hans Banzinger and Prof. Dr. Michael Burgett for identifying
the stingless bee. We also thank Dr. Antonova for running the GC/MS.
Conceived and designed the experiments: PC VB. Performed the experiments: SS. Analyzed
the data: SS MP VB PC. Contributed reagents/materials/analysis tools: PC VB. Wrote the
paper: SS PC VB MP. Co-advisor to Sirikarn Sanpa: TT SE.
1. Bankova V , Castro S de , Marcucci M. Propolis : recent advances in chemistry and plant origin . Apidologie 2000 ; 31 : 3 - 15 . doi: 10.1051/apido:2000102
2. Liberio SA , Pereira ALA , Dutra RP , Reis AS , Arajo MJAM , Mattar NS , et al. Antimicrobial activity against oral pathogens and immunomodulatory effects and toxicity of geopropolis produced by the stingless bee Melipona fasciculata Smith . BMC Complement Altern Med . 2011 ; 11 ( 108 ): 1 - 10 . doi: 10. 1186/ 1472 - 6882 - 11 -108 PMID: 22053900
3. Miorin PL , Levy Junior NC , Custodio AR , Bretz WA , Marcucci MC . Antibacterial activity of honey and propolis from Apis mellifera and Tetragonisca angustula against Staphylococcus aureus . J Appl Microbiol . 2003 ; 95 ( 5 ): 913 - 20 . doi: 10.1046/j.1365- 2672 . 2003 . 02050 .x PMID : 14633019
4. Sawaya ACHF , Cunha IBS , Marcucci MC , de Oliveira Rodrigues RF , Eberlin MN . Brazilian Propolis of Tetragonisca angustula and Apis mellifera . Apidologie . 2006 ; 37 ( 3 ): 398 - 407 . doi: 10.1051/apido
5. Michener CD , Grimaldi DA . The oldest fossil bee: Apoid history, evolutionary stasis, and antiquity of social behavior . Proc Natl Acad Sci U S A . 1988 ; 85 : 6424 - 6 . doi: 10.1073/pnas. 85.17.6424 PMID: 16593976
6. Velthuis HHW . The biology of stingless bees . Utrecht, The Netherlands: Utrecht University Press ; 1997 . 33 p.
7. Choudhari MK , Punekar SA , Ranade RV , Paknikar KM . Antimicrobial activity of stingless bee (Trigona sp.) propolis used in the folk medicine of Western Maharashtra, India . J Ethnopharmacol . 2012 ; 141 ( 1 ): 363 - 7 . doi: 10.1016/j.jep. 2012 . 02.047 PMID: 22425711
8. Sawaya ACHF , Calado JCP , dos Santos LC , Marcucci MC , Akatsu IP , Soares AEE , et al. Composition and antioxidant activity of propolis from three species of Scaptotrigona stingless bees . Journal of ApiProduct and ApiMedical Science . 2009 ; 1 ( 2 ): 37 - 42 . doi: 10.3896/IBRA.4.01.2. 03
9. Chanchao C. Bioactivity of Honey and Propolis of Tetragonula laeviceps in Thailand . In: Vit P, Pedro SRM , Roubik DW, editors. Pot-Honey . Berlin: Springer 2013 . p. 495 - 505 .
10. Ahmat N , Azmin NFN , Ghani NA , Aris SR , S., Sidek NJ , Abdullah S , et al. Bioactive Xanthones from the Pericarp of Garcinia mangostana. Middle-East J Sci Res . 2010 ; 6 ( 2 ): 123 - 7 .
11. Nguyen L-HD , Vo HT , Pham HD , Connolly JD , Harrison LJ . Xanthones from the bark of Garcinia merguensis . Phytochemistry . 2003 ; 63 ( 4 ): 467 - 70 . doi: 10.1016/ S0031-9422(02)00433-8 PMID: 12770600
12. Ragasa CY , Crisostomo CJJ , Garcia KDC , Shen C-C. Antimicrobial xanthones from Garcinia mangostana L . Philipp Scient . 2010 ; 47 : 63 - 75 .
13. Kim G-S , Jeong T-S , Kim Y , Baek N-I , Cha S , Lee J-W , et al. Human Acyl-CoA:Cholesterol Acyltransferase-inhibiting Dammarane Triterpenes from Rhus chinensis . Journal of the Korean Society for Applied Biological Chemistry . 2010 ; 53 ( 4 ): 417 - 21 . doi: 10.3839/jksabc.2010.064
14. Chen LG , Yang LL , Wang CC . Anti-inflammatory activity of mangostins from Garcinia mangostana . Food Chem Toxicol . 2008 ; 46 ( 2 ): 688 - 93 . doi: 10.1016/j.fct. 2007 . 09.096 PMID: 18029076
15. Sen AK , Sarkar KK , Mazumder PC , Banerji N , Uusvuori R , Hase TA . The structures of garcinones a, b and c: Three new xanthones from Garcinia mangostana . Phytochemistry . 1982 ; 21 ( 7 ): 1747 - 50 . doi: 10.1016/S0031-9422(82)85052- 8
16. Miyaochi T , Shuji O. Formation of (+)-eudesmin in Magnolia kobus DC. Var. borealis sarg . Phytochemistry . 1998 ; 47 ( 4 ): 665 - 70 . doi: 10.1016/S0031-9422(97)00458- 5
17. Hota RK , Bapuji M. Triterpenoids from the resin of Shorea robusta . Phytochemistry . 1993 ; 32 ( 2 ): 466 - 8 . doi: 10.1016/S0031-9422(00)95019- 2
18. Zhang Y , Jayaprakasam B , Seeram NP , Olson LK , Dewitt D. Insulin Secretion and Cyclooxygenase Enzyme Inhibition by Cabernet Sauvignon Grape Skin Compounds . J Agric Food Chem . 2004 ; 52 : 228 - 33 . doi: 10.1021/jf034616u PMID: 14733500
19. Santos GG , Alves JCN , Rodilla JML , Duarte AP , Lithgow AM , Urones JG . Terpenoids and other constituents of Eucalyptus globulus . Phytochemistry . 1997 ; 44 ( 7 ): 1309 - 12 . doi: 10.1016/S0031-9422(96) 00680- 2
20. Arriaga AC , de Mesquita AC , Pouliquen YB , de Lima RA , Cavalcante SH , de Carvalho MG , et al. Chemical constituents of Simarouba versicolor. An Acad Bras Cienc . 2002 ; 74 ( 3 ): 415 - 24 . doi: 10. 1590/ S0001-37652002000300004 PMID: 12378309
21. Seger C , Pointinger S , Greger H , Hofer O. Isoeichlerianic acid from Aglaia silvestris and revision of the stereochemistry of foveolin B . Tetrahedron Lett . 2008 ; 49 ( 27 ): 4313 - 5 . doi: 10.1016/j.tetlet. 2008 . 04.109 PMID: 19122764
22. Phongmaykin J , Kumamoto T , Ishikawa T , Suttisri R , Saifah E. A new sesquiterpene and other terpenoid constituents of Chisocheton penduliflorus . Arch Pharm Res . 2008 ; 31 ( 1 ): 21 - 7 . doi: 10.1007/ s12272- 008 - 1115 - 8 PMID: 18277603
23. Joycharat N , Plodpai P , Panthong K , Yingyongnarongkul B- e, Voravuthikunchai SP. Terpenoid constituents and antifungal activity of Aglaia forbesii seed against phytopathogens . Can J Chem . 2010 ; 88 ( 9 ): 937 - 44 . doi: 10.1139/V10- 085
24. Suntiparapop K , Prapaipong P , Chantawannakul P. Chemical and biological properties of honey from Thai stingless bee (Tetragonula leaviceps) . J Apicult Res . 2012 ; 51 ( 1 ): 45 - 52 . doi: 10.3896/IBRA.1.51. 1. 06
25. Suksamrarn S , Komutiban O , Ratananukul P , Chimnoi N , Lartpornmatulee N , Suksamrarn A. Cytotoxic prenylated xanthones from the young fruit of Garcinia mangostana . Chem Pharm Bull . 2006 ; 54 ( 3 ): 301 . doi: 10.1002/chin.200634209 PMID: 16508181
26. Jung HA , Su BN , Keller WJ , Mehta RG , Kinghorn AD . Antioxidant Xanthones from the Pericarp of Garcinia mangostana (Mangosteen) . J Agric Food Chem . 2006 ; 54 : 2077 - 82 . doi: 10.1021/jf052649z PMID: 16536578
27. Martin FW . Durian and mangosteen . In: Nagy S, Shaw PE, editors. Tropical and Subtropical Fruits: Composition, Properties and Uses AVI Pub . Co.,; 1980 . p. 407 - 14 .
28. Nakatania K , Nakahatab N , Arakawac T , Yasudac H , Ohizumia Y. Inhibition of cyclooxygenase and prostaglandin E2 synthesis by gamma-mangostin, a xanthone derivative in mangosteen, in C6 rat glioma cells . Biochem Pharmacol . 2002 ; 63 : 73 - 9 . doi: 10.1016/ S0006-2952(01)00810-3 PMID: 11754876
29. Pedraza-Chaverri J , Cardenas-Rodriguez N , Orozco-Ibarra M , Perez-Rojas JM . Medicinal properties of mangosteen (Garcinia mangostana) . Food Chem Toxicol . 2008 ; 46 ( 10 ): 3227 - 39 . doi: 10.1016/j.fct. 2008 . 07.024 PMID: 18725264
30. Burger P , Charrie-Duhaut A , Connan J , Flecker M , Albrecht P. Archaeological resinous samples from Asian wrecks: Taxonomic characterization by GC-MS . Anal Chim Acta . 2009 ; 648 ( 1 ): 85 - 97 . doi: 10. 1016/j.aca. 2009 . 06.022 PMID: 19616693
31. Xie XL , Wei M , Kakehashi A , Yamano S , Okabe K , Tajiri M , et al. Dammar resin, a non-mutagen, induces [corrected] oxidative stress and metabolic enzymes in the liver of gpt delta transgenic mouse which is different from a mutagen, 2-amino-3-methylimidazo[4,5-f]quinoline . Mutat Res . 2012 ; 748 ( 1- 2 ): 29 - 35 . doi: 10.1016/j.mrgentox. 2012 . 06.005 PMID: 22796562
32. Caligiani A , Malavasi G , Palla G , Marseglia A , Tognolini M , Bruni R. A simple GC-MS method for the screening of betulinic, corosolic, maslinic, oleanolic and ursolic acid contents in commercial botanicals used as food supplement ingredients . Food Chem . 2013 ; 136 ( 2 ): 735 - 41 . doi: 10.1016/j.foodchem. 2012 . 08.011 PMID: 23122121
33. Burger P. Caractrisation molculaire de rsines vgtales archologiques et actuelles: tude de rsines de Dipterocarpaceae . These prsente pour obtenir le grade de Docteur De l'Universite Louis Pasteur de Strasbourg . 2008 . Available: http://scd-theses.u-strasbg. fr/1583/
34. Leonhardt SD , Schmitt T , Bluthgen N. Tree resin composition, collection behavior and selective filters shape chemical profiles of tropical bees (Apidae: Meliponini) . PLoS One . 2011 ; 6 ( 8 ) :e23445 . doi: 10. 1371/journal. pone.0023445 PMID: 21858119
35. Jalil AH . Beescape for Meliponines: Conservation of Indo-Malayan Stingless Bees . Singapore: Partridge Publishing 2014 . 214 p.
36. Kaewmuangmoon J , Nonthapa P , Rattanawannee A , Winayanuwattikun P , Chanchao C. Preliminary Screening for Various Bioactivities in Honey and Propolis Extracts from Thai Bees . European J Med Plants . 2012 ; 2 ( 2 ): 74 - 92 . doi: 10.9734/EJMP/2012/941
37. Gibbons S. Anti-staphylococcal plant natural products . Nat Prod Rep . 2004 ; 21 ( 2 ): 263 - 77 . doi: 10. 1039/B212695H PMID: 15042149
38. Garedew A , Schmolz E , Lamprecht I. Microbiological and calorimetric investigations on the antimicrobial actions of different propolis extracts: an in vitro approach . Thermochimica Acta . 2004 ; 422 ( 1-2 ): 115 - 24 . doi: 10.1016/j.tca. 2004 .05.037
39. Li L , Han AR , Kinghorn AD , Frye RF , Derendorf H , Butterweck V. Pharmacokinetic properties of pure xanthones in comparison to a mangosteen fruit extract in rats . Planta Med . 2013 ; 79 ( 8 ): 646 - 53 . doi: 10. 1055/s-0032-1328543 PMID: 23673465
40. Fontanay S , Grare M , Mayer J , Finance C , Duval RE . Ursolic, oleanolic and betulinic acids: antibacterial spectra and selectivity indexes . J Ethnopharmacol . 2008 ; 120 ( 2 ): 272 - 6 . doi: 10.1016/j.jep. 2008 . 09. 001 PMID: 18835348
41. Penduka D , Mosa R , Simelane M , Basson A , Okoh A , Opoku A. Evaluation of the anti-Listeria potentials of some plant-derived triterpenes . Ann Clin Microbiol Antimicrob . 2014 ; 13 :37. doi: 10.1186/s12941- 014 - 0037 - 1 PMID: 25056181