Three xanthones have been  isolated  from  the dichloromethane extract of  the  twigs of  the Vietnamese  Calophyllum  ceriferum  Gagnep.  Ex  Stevens  collected  at  Ninh  Thuan  province. Their  structures  were  elucidated  as  1,7-dihydroxy-2,3,8-trimethoxyxanthone,  1,7-dihydroxyxanthone and 1,6-dihydroxy-5,7-dimethoxyxanthone by spectroscopic analyses

Quyet Chien, Nguyen

Thi Minh Hang, Nguyen

Van Hung, Nguyen

Vietnam Academy of Science and Technology: Journals Online

 
 
Tạp chí Khoa học và Công nghệ 50 (6) (2012) 615-619 
 
XANTHONES FROM THE TWIGS OF THE VIETNAMESE  
CALOPHYLLUM CERIFERUM GAGNEP. EX STEVENS 
Nguyen Thi Minh Hang
1, *
, Nguyen Van Hung
1
, Nguyen Quyet Chien
2 
1
Institute of Marine Biochemistry, VAST, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam 
2
Institute of Chemistry, VAST, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam 
*
E-mail: minhhang@imbc.vast.vn or hanghoahctn@yahoo.com 
Received:  11 March 2012; Accepted for publication: 21 December 2012 
ABSTRACT 
Three xanthones have been isolated from the dichloromethane extract of the twigs of the 
Vietnamese Calophyllum ceriferum Gagnep. Ex Stevens collected at Ninh Thuan province. 
Their structures were elucidated as 1,7-dihydroxy-2,3,8-trimethoxyxanthone, 1,7-
dihydroxyxanthone and 1,6-dihydroxy-5,7-dimethoxyxanthone by spectroscopic analyses. 
Keywords: Calophyllum ceriferum, 1,7-dihydroxy-2,3,8-trimethoxyxanthone, 1,7-dihydroxyxanthone, 
1,6-dihydroxy-5,7-dimethoxyxanthone. 
1. INTRODUCTION 
Calophyllum genus belongs to Clusiaceae family. According to the literature [1], in 
Vietnam the Calophyllum genus is reported to consist of 15 different species, most of which are 
wild growing. Our previous phytochemical investigations of the Vietnamese Calophyllum 
species reported the chemical constituents of two species C. inophyllum (cây Mù u) and C. 
balansae (cây Rù ri) including coumarins, triterpenes, flavones and xanthones [2, 3, 4]. C. 
ceriferum is wild growing at Ninh Thuan province, which was collected  by the botanists of 
Institute of Ecology and Biological Resources. In this context, we report on the isolation and 
characterization of three xanthones 1,5-dihydroxy-2,3,8-trimethoxyxanthone (1), 1,7-
dihydroxyxanthone (2) and 1,6-dihydroxy-5,7-dimethoxyxanthone (3) from the dichloromethane 
extract of the twigs of Calophyllum ceriferum.  
2. EXPERIMENTAL SECTION 
General Experimental Procedures: Melting points were measured with a Büchi B-545 
apparatus. EIMS were measured with a HP 5989B mass spectrometer.  NMR spectra were 
recorded by a Bruker Avance 500 MHz instrument using TMS as internal standard. 
Plant material: The twigs of Calophyllum ceriferum were collected at Ninh Thuan province and 
identified by Dr. Nguyen Tien Hiep, Institute of Ecology and Biological Resources, where a 
 
 
Nguyen Thi Minh Hang, Nguyen Van Hung, Nguyen Quyet Chien 
 
 616 
voucher specimen is deposited. 
Extraction and Isolation: The dried and powdered material (210 g) was extracted with MeOH 
at room temperature (3 times, 2 days/time). After a part of MeOH was evaporated in vacuo, the 
MeOH-solution was extracted successively by n-hexane and dichloromethane to obtain n-hexane 
extract (F1, 4 g) and dichloromethane extract (F2, 2 g). F2 was subjected to column 
chromatography on silica gel, eluted with gradient n-hexane-dichloromethane and 
dichloromethane-methanol to obtain 4 fractions  F3-F6.  Then F4 continue to be seperated by 
column chromatography on silica gel, eluted with  n-hexane-dichloromethane 50 % to obtain 5 
fractions F7-F11. Further separation of F8 by gel filtration on Sephadex LH-20 with MeOH-
CH2Cl2 8:2 yielded  a main fraction, which was crystallized in acetone to obtain compound 3 
(2mg). F9 and F10 were filtrated on Sephadex LH-20 with MeOH-CH2Cl2 8 - 2 to yield 2 
fractions F12-F13. Crystallization of F12 in acetone yielded xanthone 1 (2 mg). F13 was 
crystallized in acetone to obtain xanthone 2 (5 mg). 
1,7-dihydroxy-2,3,8-trimethoxyxanthone (1): yellow needles (n-hexane-acetone), mp. 204 
0
C. 
TLC: Rf 0.3 (n-hexane/acetone 7/3). EIMS m/z (%): 318 ([M]
+
, 100), 303 ([M-CH3]
+
, 58), 275 
(59), 260 (75), 245 (45), 153 (24), 93 (26), 69 (19). 
1
H and 
13
C NMR see table 1. 
1,7-dihydroxyxanthone (2): yellow crystal (n-hexane-acetone), mp. 235-236 
0
C. TLC: Rf 0.46 (n-
hexane/acetone 7/3). EIMS m/z (%): 228 ([M]
+
, 100), 200 (15), 171 (5), 144(8), 115 (16), 57 
(21). 
1
H and 
13
C NMR see table 1. 
1,6-dihydroxy-5,7-dimethoxyxanthone (3): yellow crystal (n-hexane-acetone), mp. 215-216. 
TLC: Rf 0.4 (n-hexane/acetone 7/3). 
1
H and 
13
C NMR see table 1. 
3. RESULTS AND DISCUSSION 
From the dichloromethane extract of the twigs of C. ceriferum, 3 xanthones have been 
isolated on the basis of chromatographic methods. 
 
Xanthone 1 was obtained as yellow needles, mp 204 
0
C, which gave a HREIMS (High 
Resolution Electron Impact Mass Spectroscopy) parent ion at m/z 318.0789 Da indicating a 
molecular formula of C16H14O7. 
13
C NMN spectrum showed the resonance of 16 carbons 
corresponding to 3 methyl, 3 methine groups and 10 aromatic quaternary carbons including a 
conjugated carbonyl (δC 180.90). The typical signals at δC 180.90 (C-9), 152.96 (C-4a), 150.76 
(C-4b), 114.51 (C-8a) and 104.45 (C-9a) revealed a xanthone skeleton for this compound. The 
1
H NMR spectrum showed the presence of  a chelated hydroxyl group (δH 13.02), a phenolic 
hydroxyl group (δH 6.00) and three aromatic protons appearing as two doublets at δH 7.38 and 
7.16 (2H, d, J=9.0 Hz, H-8, H-7) and a singlet at δH 6.42, which belonged  to two distinct 
benzene rings. These data indicated a pentasubstituted xanthone skeleton for this compound. The 
long- range couplings in the HMBC spectrum between chelated hydroxyl proton with C-2, C-9a 
and  C-1 allowed to prove that this hydroxyl group was located at C-1. Correlations between the 
protons of 3 methoxyl groups with C-2, C-3 and C-8 indicated the position C-2, C-3 and C-8 of 
these groups, respectively. Correlations between the remaining phenolic hydroxyl proton with  
 
 
Xanthones from the twigs of the Vietnamese Calophyllum ceriferum Gagnep. Ex Stevens 
 
 617 
C-8, C-7 and C-6 clearly proved the position C-7 of this group. Full analyses of 1D and 2D 
NMR spectra allowed to establish the structure of this compound as 1,7-dihydroxy-2,3,8-
trimethoxyxanthone.  
The 
13
C NMR of 2 exhibited 13 carbon signals assigned by DEPT experiment to 6 methine 
groups, 4 oxygenated quaternary carbons, one carbonyl group and 2 other quaternary carbons. 
This together with the molecular peak at m/z 228 in the EIMS spectrum corresponding to a 
molecular formula of C13H8O4. The 
13
C NMR data also suggested a xanthone skeleton for this 
compound. The 
1
H NMR spectrum showed resonance signals of a chelated hydroxyl proton (δH 
13.02), a phenolic hydroxyl proton (δH 6.00) and 6 aromatic protons  appearing as one ABX and 
one AB2 spin coupling systems. The first system AB2 composed of three protons appearing at  
δH 6.71, 6.87 (2H, dd, J = 8.5, 0.5 Hz, H-2, H-4) and  7.52 (t, J=  8.5, H-3), which indicated the 
presence of a 1,2,3-trisubstitued  benzene ring (ring A).  The presence of a 1,2,4-trisubstituted 
benzene ring (ring C) was deduced from the second coupling system ABX of three protons at  δH 
7.33 (d, J = 9.0 Hz, H-5), 7.25 (dd, J = 9.0, 3.0, H-6) and 7.47 (d, J = 2.5 Hz, H-8). These 
spectra evidences revealed a disubstituted xanthone skeleton for this compound. The position of 
two hydroxyl groups were established by the correlations in the HMBC spectrum at C-1 and            
C-7. By combined analysis of the spectra data, compound 2 was identified as 1,7-
dihydroxyxanthone. This compound have been first isolated from Hypericum mysorense [5] and 
Mesua thwaitesii [6].  
Xanthone 3 was isolated as yellow crytals, mp 215 - 216 
0
C. Molecular formula of 3 was 
deduced to be C15H12O6 by the 
13
C NMR spectra data. The 
13
C NMR had resonance signals of 15 
carbons corresponding to 2 methyl, 4 methine and one carbonyl groups, 6 oxygenated quaternary 
carbons and 2 other quaternary carbons. The 
1
H NMR spectrum showed the presence of 4 
aromatic protons as a singlet at δH 7.44 and a AB2 coupling system of three protons at  δH 6.80, 
7.00 (2 dd, J = 8.5, 0.5 Hz, H-2, H-4) and 7.00 (t, J = 8.5 Hz, H-3). The remaining signals 
belonged to one chelated hydroxyl proton (δH 12.75) and six protons (δH 4.03, 4.11) 
corresponding to two methoxyl group. The NMR spectra data indicated the tetrasubstituted 
skeleton for this compound. Correlations between the chelated hydroxyl proton with C-1, C-2 
and C-9a confirmed the position C-1 of this proton. The position of other substituted groups 
were also deduced from the correlations in the HMBC spectrum. By full analyses of 1D and 2D 
NMR spectra, the structure of 3 was identified as 1,6-dihydroxy-5,7-dimethoxyxanthone.  This 
compound have been first isolated from Hypericum ascyron and Caraipa densiflora [7]. 
Table 1. 
1
H NMR (CDCl3, 500 MHz) and 
13
C NMR (CDCl3, 125 MHz) data of 1, 2, 3. 
 1 2 3 
δC  
(ppm) 
δH  (m, Hz) δC  (ppm) δH  (m, Hz) δC  (ppm) δH  (m, Hz) 
1 154.46 - 161.26 - 161.76 - 
2 131.75 - 109.63 6.71 (dd, 8.5, 0.5) 110.47 6.80 (dd, 8.5, 
0.5) 
3 159.90 - 136.56 7.52 (t, 8.5) 136.10 7.57 (t, 8.5) 
4 89.89 6,42 (s) 107.09 6.87 (dd, 8.5, 0.5) 110.47 7.0 (dd, 8.5, 0.5) 
4a 152.96 - 156.40 - 156.11 - 
 
 
Nguyen Thi Minh Hang, Nguyen Van Hung, Nguyen Quyet Chien 
 
 618 
4b 150.76 - 150.24 - 146.34 - 
5 113.87 7,16 (d, 9.0) 119.07 7.33 (d, 9.0) 145.01 - 
6 122.63 7.38 (d, 9.0) 125.37 7.25 (dd, 9.0, 3.0) 145.77 - 
7 145.57  153.65 - 134.65 - 
8 144.25  108.20 7.47 (d, 2.5) 99.79 7.44 (s) 
8a 114.51 - 120.77 - 113.20 - 
9 180.90 - 182.41 - 181.19 - 
9a 104.45 - 108.46 - 108.53 - 
2-OCH3 60.91 3.91 (s) - - - - 
3-OCH3 56.31 3.96 (s) - - - - 
8-OCH3 62.84 4.03 (s) - - - - 
1-OH  13.02 (s) - 12.60 (s) - 12.75 
5-OH  6.00 (s) - - -  
7-OH    3.83 (s) - - 
5-OCH3     56.59 4.03 (s) 
7-OCH3     61.73 4.11 (s) 
4. CONCLUSION 
 In continuation of our investigation on the phytochemistry of the Vietnamese Calophyllum 
species. Three xanthones were isolated from the dichloromethane extract of Calophyllum 
ceriferum Gagnep. Ex Stevens collected at Ninh Thuan province. Their structure were identified 
as 1,7-dihydroxy-2,3,8-trimethoxyxanthone, 1,7-dihydroxyxanthone and 1,6-dihydroxy-5,7-
dimethoxyxanthone by means of spectroscopic methods. These compounds are being evaluated 
for the antioxidant and antibacterial  activities, and cytotoxicity on some human cancer cell 
lines.  
REFERENCES 
1. Pham Hoang Ho - Flora of Vietnam, Youth Publishing House, Ho Chi Minh City, vol. I, 
1999. 
2. Nguyen Thi Minh Hang, Nguyen Quyet Chien, Nguyen Van Hung - Coumarins of the 
leaves of Calophyllum inophyllum, Vietnamese Journal of Chemistry 43 (6) (2005) 683-
687. 
3. Nguyen Thi Minh Hang, Nguyen Quyet Chien, Nguyen Van Hung - Two coumarins and 
two xanthones from the leaves and twigs of Calophyllum balansae, Advances in Natural 
Sciences 6 (3) (2005) 239-244. 
4. Nguyen Thi Minh Hang, Nguyen Quyet Chien, Nguyen Van Hung - Chemical 
constituents of the Vietnamese Calophyllum inophyllum seed oil, Advances in Natural 
Sciences 6 (3) (2005) 245-249. 
 
 
Xanthones from the twigs of the Vietnamese Calophyllum ceriferum Gagnep. Ex Stevens 
 
 619 
5. A. A. Leslie Gunatilaka, A. M. Y. Jasmin De Silva and Subramaniam Sotheeswaran - 
Minor xanthones of Hypericum mysorence, Phytochemistry, 21 (7) (1982) 1751-1753. 
6. Wickramasinghe M. Bandaranayake, Sathiaderan S. Selliah and M. Uvais S. -  
Sultanbawa, Xanthones and 4-phenylcoumarins of Mesua thwaitesii, Phytochemistry 14 
(1) (1975), 265-269. 
7. Dictionary of Natural Products on CD-ROM, Chapman & Hall_CRC 1982-2007. 
TÓM TẮT 
CÁC HỢP CHẤT XANTON TỪ CÀNH NHỎ CÂY CÒNG SÁP (CALOPHYLLUM 
CERIFERUM GAGNEP. EX STEVEN) Ở VIỆT NAM 
Nguyễn Thị Minh Hằng1, Nguyễn Văn Hùng1, Nguyễn Quyết Chiến2 
1Viện Hóa sinh Biển, Viện KHCNVN, 18 Hoàng Quốc Việt, Cầu Giấy, Hà Nội 
2Viện Hóa học, Viện KHCNVN, 18 Hoàng Quốc Việt, Cầu Giấy, Hà Nội 
*
E-mail: minhhang@imbc.vast.vn or hanghoahctn@yahoo.com 
Chi Còng (Calophyllum) là một trong số các chi thuộc họ Măng cụt (Clusiaceae). Ở Việt 
nam, chi này có 15 loài nhưng còn ít được nghiên cứu về thành phần hóa học cũng như hoạt tính 
sinh học. Các nghiên cứu trước đây của chúng tôi về 2 loài Mù u (C. inophyllum) và Rù ri                
(C. balansae) của Việt Nam cho thấy chúng là nguồn giàu có các hợp chất coumarin, tecpenoit 
và xanton. Tiếp tục hướng nghiên cứu này, chúng tôi đã phân lập và xác định được cấu trúc của 
3 hợp chất xanton là 1,7-dihydroxy-2,3,8-trimethoxyxanthone (1), 1,7-dihydroxyxanthone (2) 
and 1,6-dihydroxy-5,7-dimethoxyxanthone (3) từ dịch chiết diclometan của lá cây Còng sáp             
(C. ceriferum) mọc ở tỉnh Ninh Thuận. Các hợp chất này đang tiếp tục được đánh giá về một số 
hoạt tính sinh học như kháng vi sinh vật kiểm định, chống ôxi hóa và khả năng gây độc tế bào 
trên một số dòng tế bào ung thư người. 
 
Từ khóa: còng sáp, xanton, 1,7-dihydroxy-2,3,8-trimethoxyxanthone, 1,7-dihydroxyxanthone, 
1,6-dihydroxy-5,7-dimethoxyxanthone, Ninh Thuận. 
 


XANTHONES FROM THE TWIGS OF THE VIETNAMESE   CALOPHYLLUM CERIFERUM GAGNEP. EX STEVENS

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XANTHONES FROM THE TWIGS OF THE VIETNAMESE CALOPHYLLUM CERIFERUM GAGNEP. EX STEVENS

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