Thelephantins I-N: p-terphenyl derivatives from the inedible mushroom Hydnellum caeruleum

Article abstract of DOI:10.1016/j.phytochem.2004.02.018

Phytochemical investigation of the methanolic extract of the fruiting bodies of the inedible mushroom Hydnellum caeruleum resulted in the isolation of six p-terphenyl derivatives named thelephantins I-N (1-6), together with a known compound, dihydroaurantiacin dibenzoate (7). These structures were determined by high-resolution MS, 2D NMR, IR and UV spectroscopic analysis, and by the chemical reactions.

Full text of DOI:10.1016/j.phytochem.2004.02.018

Phytochemistry 65 (2004) 1179–1184
www.elsevier.com/locate/phytochem
Thelephantins I–N:
p-terphenyl derivatives from the inedible mushroom
Hydnellum caeruleum
Dang Ngoc Quanga,c, Toshihiro Hashimotoa, Yuki Hitakaa, Masami Tanakaa,
Makiko Nukadab, Isao Yamamotob, Yoshinori Asakawaa,*
aFaculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan
bFaculty of Food Culture, Kurashiki Sakuyo University, Kurashiki 710-0290 Japan
cFaculty of Chemistry, Hanoi University of Education, 136 Xuan Thuy Road, Cau Giay, Hanoi, Viet Nam
Received 23 October 2003; received in revised form 6 January 2004
Abstract
Phytochemical investigation of the methanolic extract of the fruiting bodies of the inedible mushroom Hydnellum caeruleum
resulted in the isolation of six p-terphenyl derivatives named thelephantins I–N (1–6), together with a known compound,
dihydroaurantiacin dibenzoate (7). These structures were determined by high-resolution MS, 2D NMR, IR and UV spectroscopic
analysis, and by the chemical reactions.
# 2004 Elsevier Ltd. All rights reserved.
Keywords: Hydnellum caeruleum; Thelephoraceae; Fungi; Thelephantins; 3-Pyridinecarboxylate
1. Introduction
wish to report here on their isolation and structural
elucidation.
The mushrooms belonging to the Thelephoraceae
family have been shown to be a rich source of p-terphe-
nyl compounds. Sullivan et al. (1967) reported the iso-
lation of atromentin, aurantiacin, dihydroaurantiacin
dibenzoate, polyporic acid and thelephoric acid from
Hydnellum genus. Recently, ganbajunins A–G from
Thelephora ganbajun (Hu et al., 2001a,b) and thele-
phorin A from Thelephora vialis (Tsukamoto et al.,
2002) were reported. We also reported the isolation of
curtisians E–Q from the Badisiomycete fungi, Paxillus
curtisii (Quang et al., 2003a,b,c) and thelephantins A–H
(Quang et al., 2003d,e) from Thelephora aurantiotincta.
In the course of our investigation of the biologically
active substances from the inedible mushrooms, we
investigated the chemical constituents of Hydnellum
caeruleum and isolated six new p-terphenyl derivatives
named thelephantins I–N (1–6) together with a known
p-terphenyl, dihydroaurantiacin dibenzoate (7). We
2. Results and discussion
The methanolic extract of the fruit bodies of H.
caeruleum was subjected to Sephadex LH-20 and SiO2
column chromatography, and then prep. HPLC to
afford thelephantins I–N (1–6), together with a known
compound dihydroaurantiacin dibenzoate (7) (Sullivan
et al., 1967).
The molecular formula of thelephantin I (1) was
determined to be C26H18O7 by HR-FABMS. The FT-
IR, UV and 13C NMR spectra of compound 1 indicated
the presence of a hydroxyl (3376 cmꢀ1) group and a
para-quinone (1661 cmꢀ1, lmax 397 nm, ꢀC 182.2 and
1
184.3). The H NMR spectrum of 1 (Table 1) indicated
the presence of a methoxyl group and a benzoyl group
and its spectrum was very similar to that of 20-O-
methylatromentin (8) (Hu et al., 2001a), except for the
signals of a benzoyl group suggesting that compound 1 is
a p-terphenyl derivative. The positions of the benzoyl and
methoxyl groups were located at 20 and 50, respectively,
* Corresponding author. Tel.: +88-622-9611; fax: +88-655-3051.
E-mail address: asakawa@ph.bunri-u.ac.jp (Y. Asakawa).
0031-9422/$ - see front matter # 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.phytochem.2004.02.018

1180
D.N. Quang et al. / Phytochemistry 65 (2004) 1179–1184
Table 1
1H-NMR spectral data for compounds 1–6 (600 MHz, CD3OD)
H
1
2
3
4
5
6
2, 6
30,0 5
200
500
600
3a, 7a
4a, 6a
5a
7.27 d 8.8
6.79 d 8.8
7.21 d 8.8
6.83 d 8.8
6.83 d 8.8
7.21 d 8.8
8.01 d 8.2
7.49 dd 7.4, 8.2
7.65 t 7.4
7.27 d 8.8
6.75 d 8.8
7.27 d 8.8
6.75 d 8.8
6.75 d 8.8
7.27 d 8.8
7.74 dd 1.4, 8.5
7.26 t 8.5
7.43 t 8.5
7.26 d 8.8
6.74 d 8.8
7.30 d 8.8
6.77 d 8.8
6.62 d 8.8
7.21 d 8.8
7.76 d 8.5
7.28 (overlap)
7.44 t 7.7
8.01 d 8.5
7.47 t 8.2
7.59 m
7.22 d 8.8
6.75 d 8.8
7.24 d 8.8
6.65 d 8.8
6.65 d 8.8
7.24 d 8.8
7.79 d 8.2
7.28 t 8.2
7.47 t 8.2
7.79 d 8.2
7.28 t 8.2
7.47 t 8.2
7.79 d 8.2
7.26 d 8.8
6.75 d 8.8
7.26 d 8.8
6.75 d 8.8
7.26 d 8.8
6.75 d 8.8
6.75 d 8.8
7.26 d 8.8
7.77 dd 1.1, 8.6
7.29 t 7.7
7.46 t 7.7
3
7.09 s
7.02 s
7.81 d 8.5
7.32 dd 7.7, 8.5
7.49 t 7.7
3b
4b, 6b
5b
7b
7.97 d 8.5
1c
3c
4c
5c
6c
7c
2d
3.81 s
7.74 d 8.5
7.26 t 8.5
7.43 t 8.5
7.26 t 8.5
7.74 d 8.5
7.76 d 8.5
7.28 (overlap)
7.44 t 7.7
7.28 (overlap)
7.76 d 8.5
7.97 d 8.5
7.49 t 8.5
7.64 t 8.5
7.49 t 8.5
7.97 d 8.5
1.84 s
8.13 dd 1.4, 8.2
7.47 dd 7.7, 8.2
7.62 t 7.7
7.47 dd 7.7, 8.2
8.13 dd 1.4, 8.2
8.11 d 8.0
7.36 dd 4.7, 8.0
8.58 brd 4.7
8.84 brs
by the NOE correlations between (1) H-3a/H-2 and
H-3; (2) CH3O-(H-1c)/H-500 and H-600 in its NOESY
spectrum. In addition, the 13C NMR and UV spectral
data of 1 were in good agreement with those of 20-O-
methylatromentin (Hu et al., 2001a). Thus, thelephantin
I (1) was determined to be 4,400-dihydroxy-20-benzoy-
loxy-50-methoxy [1,10:40,100-terphenyl]-30,60-dione as shown.
A molecular formula of C32H22O8 was determined for
thelephantin J (2) from the molecular ion peakat m/z
534.1341 [M]+ (calc. for C32H22O8 534.1315) obtained
Table 2
13C-NMR spectral data for compound 1–6 (150 MHz, CD3OD)
C
1
2
3
4
5
6
1
120.8
132.9
115.9
159.9
129.4
148.3
184.3
129.2
156.3
182.2
122.0
133.3
115.7
159.2
115.7
133.3
165.7
134.8
131.3
129.9
135.4
124.9
132.6
116.0
158.0
124.1
132.6
142.7
124.1
132.6
142.7
124.9
132.6
116.0
158.0
116.0
132.6
166.4
130.1
130.7
129.4
134.6
124.9
132.6
116.0
158.0
124.1
135.0
134.8
124.1
135.0
142.7
124.9
132.7
116.1
158.3
115.9
132.0
166.4
130.8
130.7
129.5
134.6
166.3
129.8
130.5
129.5
134.2
131.1
166.4
130.8
130.7
129.5
134.6
129.5
130.7
123.2
131.9
116.1
158.8
131.8
140.9
140.9
131.8
140.9
140.9
123.2
131.9
116.1
158.8
116.1
131.9
165.4
129.4
130.9
129.6
135.0
165.4
129.4
130.9
129.6
135.0
130.9
165.3
129.4
131.0
129.9
135.3
129.9
131.0
169.6
20.0
125.1
132.9
115.9
157.9
122.4
137.5
144.5
119.7
139.2
142.7
115.0
152.6
99.4
124.8
132.6
116.0
158.2
124.1
134.9
142.9
124.1
134.6
142.9
124.8
132.6
116.0
158.1
116.0
132.6
166.3
129.9
130.7
129.6
134.8
2.6
3.5
4
10
20
30
40
1
by HR-FABMS. The H NMR spectrum (Table 1) of
500
compound 2 showed the signals of eight aromatic pro-
tons and two benzoyl groups. The 13C NMR spectrum
(Table 2) of 2 displayed the resonances of phenolic car-
bons (ꢀC 142.7, 158.0) and carbonyl ester (ꢀC 166.4). The
1H and 13C NMR spectral data of 2 were very similar to
those of thelephorin A (Tsukamoto et al., 2002) and
thelephantins A–H (Quang et al., 2003d,e) suggesting
that compound 2 is a 20,50-dibenzoyl-p-terphenyl deri-
600
100
200
3
400
148.3
143.8
107.4
166.3
129.8
130.8
129.6
134.7
165.9
130.0
131.2
130.0
135.2
131.2
500
600
1a
2a
3a, 7a
4a, 6a
5a
1b
2b
3b
4b, 6b
5b
7b
1c
1
vative. In addition, the signals observed in the H and
13C NMR spectrum of 2 (Tables 1 and 2) showed exact
overlapping along the terphenyl bond axis, suggesting
that this compound has symmetrical structure (Yun et
al., 2000; Quang et al., 2003a). Further, the location of
two benzoyl groups was deduced by oxidative treat-
ment. Compound 2 was oxidized by di-ammonium cer-
ium (IV) nitrate to give quinone derivative 9 (UV lmax
495 nm and IR 1671 cmꢀ1) (Chart 1) indicating that 2
had a hydroquinone moiety. The presence of quinone
group was also confirmed by observation of the mole-
cular ion peakat m/z 555.1039 (C32H20O8Na) in HR-
FABMS, indicating the loss of two molecular weights
from the original compound (2). The 13C NMR spectral
data of 9 resembled those of 2 except for the presence of
61.8
166.4
130.1
130.7
129.4
134.6
129.4
130.7
164.5
126.7
139.0
125.2
154.4
2c
3c
4c
5c
6c
7c
151.1
1d
2d

D.N. Quang et al. / Phytochemistry 65 (2004) 1179–1184
1181
signal at 176.9 ppm in place of the phenolic carbon at
142.7 ppm and absorption maximum at 495 nm in its
UV spectrum suggesting the presence of a para-benzo-
quinone moiety in 9 (Quang et al., 2003b). In addition,
no bathochromic shift of absorption maximum at 495
nm in its UV spectrum was observed when one and then
ten drops of a H3BO3 solution (1% in water) was added,
indicating that compound 9 was not an ortho-benzo-
quinone. Consequently, thelephantin J (2) was found to
be 30,4,400,60-tetrahydroxy-20,50-dibenzoyloxy [1,10:40,100-
terphenyl] as depicted in Chart 1.
Thelephantin K (3) was shown to have a molecular
formula of C39H26O9 by HR-FABMS. Inspection of its
1H NMR spectral data suggested the presence of three
benzoyl groups in 3. Compound 3 also displayed 39
carbon signals in its 13C NMR including three phenolic
carbons, three carbonyl esters. By comparing its NMR
spectral data with those of thelephantin J (2) indicated
that compound (3) possessed three benzoyl groups at
the central aromatic ring. Thus, thelephantin K (3) was
deduced to be 4,400,60-trihydroxy-20,30,50-tribenzoyloxy
[1,10:40,100-terphenyl] as shown.
Chart 1. The structures of compounds 1–9.

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D.N. Quang et al. / Phytochemistry 65 (2004) 1179–1184
was determined to be 3-pyridinecarboxyl. It was further
confirmed by comparison of the 13C NMR spectral data
of 6 with those of the commercially available phenyl 3-
pyridinecarboxylate (Chart 2). The 13C NMR signals of
3-pyridinecarboxyl partial structure of 6 were almost
identical with those of phenyl 3-pyridinecarboxylate.
Two substitutions groups at the central aromatic ring
were determined to be at C-30 and C-50 by comparing its
13C NMR spectral data to those of thelephantin J (2)
and thelephantins A–H (Quang et al., 2003d,e). Thus,
the structure of thelephantin N (6) was determined to be
30,4,400,60-tetrahydroxy-20-benzoyloxy-50-(3-pyridinecarb-
oxyl) [1,10:40,100-terphenyl] as shown. This is the second
report of a terphenyl compound possessing a nitrogen
atom. Previously, sarcodonin, a p-terphenyl derivative
with an N-oxide and a hydroxylamine, was reported
from fruiting bodies of Sarcodon leucopus belonging to
the same family Thelephoraceae (Corrada et al., 2000).
Chart 2. The important 13C NMR data of phenyl 3-pyridinecarboxylate
(CD3OD).
HR-FABMS of thelephantin L (4) indicated the
molecular formula C41H28O10. The IR spectrum indi-
cated the presence of a hydroxyl (3452 cmꢀ1), carbonyl
ester (1748 cmꢀ1) and a benzene (1611, 1525 cmꢀ1
)
groups. The H and 13C NMR spectra of compound 4
were very similar to those of thelephantin K (3) except
for the presence of one acetyl group [ꢀH 1.84 (s) and ꢀC
169.6, 20.0]. Thus, the structure of thelephantin L (4)
was deduced to be 4,400-dihydroxy-20,30,50-tribenzoyl-
oxy-60-acetyloxy [1,10:40,100-terphenyl] as shown.
1
3. Experimental
The molecular formula of thelephantin M (5) was
1
3.1. General
found to be C32H20O9 by HR-FABMS. The H NMR
spectrum (Table 1) of 5 showed the presence of fourteen
aromatic and two singlet aromatic protons. The spectral
data of compound 5 resembled those of thelephantin H
(Quang et al., 2003e) suggesting that it was also a p-ter-
phenyl derivative possessing a dibenzofuran unit due to
the 0l0ong-range correlations between (i) H-300 and C-100,
C-2 , C-400 and C-500; (ii) H-600 and C-40, C-200, C-400 and
C-500, except for the notable difference in the NMR
spectral data of two substitution groups at the central
aromatic ring. Two substitution groups were deter-
mined to be benzoyl groups by its 2D NMR spectro-
scopy and located at C-20 and C-50 by the NOE
correlations between (i) H-3a and H-6; (ii) H-3c and H-
600 in its NOESY spectrum. Based on the above discus-
sion, thelephantin M (5) was found to be di[benzoic
acid] 2,7,8-trihydroxy-3(-4-hydroxyphenyl)dibenzofuran-
1,4-diyl ester as shown.
NMR spectra were recorded on Varian Unity 600
1
(600 MHz for H NMR and 150 MHz for 13C NMR)
using CD3OD unless otherwise stated. Chemical shifts
are given with TMS (ꢀ 0.00) used as internal standard
(1H-NMR) and ꢀ 49.00 (ppm) from CD3OD as a stan-
dard (13C-NMR). IR spectra were measured on JASCO
FT/IR-5300 spectrophotometer. UV spectra were
obtained on a Shimadzu UV-1650PC in MeOH solu-
tion. Mass spectra including high-resolution FAB mass
spectra were recorded on a JEOL JMS AX-500 spec-
trometer. Column chromatography was carried out on
silica gel 60 (0.2–0.5 mm, and 0.04–0.063 mm, Merck)
and Sephadex LH-20 (Amersham Pharmacia Biotech,
CHCl3–MeOH, 1:1). Preparative medium-pressure
liquid chromatography (MPLC) was performed with a
Work-21 pump (Lab-Quatec Co., Ltd) and carried out
by Lobar column chromatography (Merck). HPLC was
performed on a Shimadzu liquid chromatograph LC-
10AS with RID-6A and SPD-10A detectors using a
Waters 5C18-AR-II column. The spots on TLC were
detected under UV 254 nm and by spraying with Godin
Thelephantin N (6) was obtained as grayish solid; its
molecular formula was determined to be C31H21O8N by
HR-FABMS indicated the presence of a nitrogen atom.
The NMR spectral data (Tables 1 and 2) of 6 were very
similar to those of thelephantin J (2) indicating that it
was a p-terphenyl derivative with two substitution groups,
ꢁ
reagent (Godin, 1954), followed by heating at 120 C.
1
one of which was a benzoyl group. The H NMR spec-
tral data of the other substitution group showed the
presence of four aromatic proton signals, in which H-4c
3.2. Material
Fruit bodies of Hydnellum caeruleum was collected in
Yatugatake mountain, Shinshou, Nagano Prefecture,
Japan in August 1998 and identified by M. Nukada
at Kurashiki Sakuyo University, Kurashiki, Japan. The
voucher specimen (K1998-1) has been deposited in
Faculty of Food Culture, Kurashiki Sakuyo University,
Kurashiki 710-0290 Japan.
1
correlated to H-3c and H-5c in its H–1H COSY spec-
trum, and the signal of H-7c was shifted to the down
field at ꢀH 8.84 (br s). In addition, the 13C NMR spectrum
(Table 2) of this substitution group showed the presence
of one carbonyl ester and five aromatic carbons. Thus,
the second substitution group at the central aromatic ring

D.N. Quang et al. / Phytochemistry 65 (2004) 1179–1184
1183
3.3. Extraction and isolation
1735, 1610, 1523 cmꢀ1
and 2).
.
1H and 13C NMR (Tables 1
The dried fruit bodies of H. caeruleum (20 g) was
extracted with MeOH followed by concentration in
vacuo to give a residue (4.4 g) which was subjected to
Sephadex LH-20 and then SiO2 column chromato-
graphy using CHCl3–MeOH (1:1) as eluent to give 6
fractions. Fraction 1 (23.8 mg) was further purified by
preparative HPLC with a reversed phase RP-18 column,
solvent system CH3CN–H2O (1:1) yielded compounds 1
(15.2 mg), 4 (2.2 mg). Fraction 2 (307.4 mg) was treated
in the same manner as fraction 1 to give compounds 1
(21.2 mg), 4 (7.7 mg) and 7 (4.4 mg). Fraction 3 (92.8
mg) was treated in the same procedure to give sub-frac-
tions 1 and 2, then purified by prep. HPLC with a
DIOL column using EtOAc as solvent to afford com-
pounds 1 (3.0 mg), 2 (5.9 mg) and 3 (25.7 mg). Fraction
4 (257.8 mg) gave compound 2 in pure state. Fraction 5
(56.1 mg) and 6 (49.0 mg) were treated in the same
manner as fraction 1 to yield compounds 2 (7.7 mg), 5
(9.8 mg), and 6 (4.1 mg) from Fr. 5 and 2 (3.4 mg) and 5
(5.6 mg) from Fr. 6, respectively.
3.3.6. Thelephantin N (6)
Grayish solid; Positive FAB-MS: 536 [M+H]+; HR-
FABMS m/z 536.1373 (C31H22O8N, requires m/z
536.1345). UV lmax nm (log ꢁ): 226.6 (4.2), 264.0 (4.2).
IR (KBr): 3354, 1743, 1610, 1525 cmꢀ1. H and 13C
1
NMR (Tables 1 and 2).
3.3.7. Oxidation of thelephantin J (9)
Thelephantin J (2) (20.0 mg) was oxidized by
di-ammonium cerium (IV) nitrate (25 mg) in MeCN (2
ml) at 0–5 ꢁC for 25 min. The reaction mixture was
treated in the same manner as curtisian I (Quang et al.,
2003b) to afford 9 (10.8 mg). UV (MeOH): lmax (log ꢁ)
237 (4.4), 495 (3.1); IR (KBr): 3349, 1737, 1671, 1610,
1515, 1452, 1239, 1176, 1108, 1024 cmꢀ1 13C NMR
.
(DMSO-d6): d 176.9 (C-30, C-60), 167.3 (C-1a, C-1c),
157.9 (C-4, C-400), 149.0 (C-20, C-50), 132.9 (C-5a, C-5c),
131.1 (C-2, C-6, C-200, C600), 129.1 (C10, C-40), 129.3 (C-
3a, C-7a, C-3c, C-7c), 128.6 (C-4a, C-6a, C-4c, C-6c),
120.0 (C1, C100), 115.0 (C-3, C-5, C-300, C-500); FABMS
m/z 555 [M+Na]+; HR-FABMS m/z 555.1039
(C32H20O8Na, 555.1056).
3.3.1. Thelephantin I (1)
Reddish orange solid; Positive FAB-MS: 443
[M+H]+; HR-FABMS m/z 443.1086 (C26H19O7,
requires m/z 443.1131). UV lmax nm (log ꢁ): 241.5 (4.4),
248.5 (4.4), 397.0 (3.6). IR (KBr): 3376, 1740, 1661,
1606, 1513 cmꢀ1. 1H and 13C NMR (Tables 1 and 2).
Acknowledgements
The authors thankMiss. Y. Okamoto (TBU) for the
recording mass spectra.
3.3.2. Thelephantin J (2)
Grayish solid; Positive FAB-MS: 534 [M]+; HR-
FABMS m/z 534.1341 (C32H22O8, requires m/z
534.1315). UV lmax nm (log ꢁ): 231.0 (4.5), 262.0 (4.2).
References
IR (KBr): 3258, 1720, 1610, 1526 cmꢀ1
NMR (Tables 1 and 2).
.
1H and 13C
Corrada, G., Placido, N., Cinzia, P., Concetta, R., Corrado, T., 2000.
An unusual nitrogenous terphenyl derivative from fruiting bodies of
the Basidiomycete Sarcodon leucopus. Journal of Natural Products
63, 347–351.
3.3.3. Thelephantin K (3)
Grayish solid; Positive FAB-MS: 639 [M+H]+; HR-
FABMS m/z 639.1656 (C39H27O9, requires m/z
639.1655). UV lmax nm (log ꢁ): 231.4 (4.5), 260.8 (4.1).
Godin, P., 1954. A new spray reagent for paper chromatography of
polyols and cetoses. Nature (London) 174, 134.
Hu, L., Gao, M.J., Liu, J.K., 2001a. Unusual poly (phenylacetoxy)-
substituted 1,10:40,100-terphenyl derivatives from fruiting bodies of
the Basidiomycete Thelephora ganbajun. Helvetica Chimia Acta 84,
3342–3349.
IR (KBr): 3447, 1745, 1611, 1526 cmꢀ1
NMR (Tables 1 and 2).
.
1H and 13C
Hu, L., Liu, J.K., 2001b. Two novel phenylacetoxylated p-terphenyls
from Thelephora ganbajun Zang. Zeitschrift fur Naturforschung C
56, 983–987.
3.3.4. Thelephantin L (4)
¨
Grayish solid; Positive FAB-MS: 703 [M+Na]+;
HR-FABMS m/z 703.1555 (C41H28O10Na, requires m/z
703.1580). UV lmax nm (log ꢁ): 232.0 (4.7), 267.2 (4.3).
Quang, D.N., Hashimoto, T., Nukada, M., Yamamoto, I., Tanaka,
M., Asakawa, Y., 2003a. Curtisians E–H: four p-terphenyl deriva-
tives from the inedible mushroom Paxillus curtisii. Phytochemistry
64, 649–654.
IR (KBr): 3452, 1748, 1611, 1525 cmꢀ1
NMR (Tables 1 and 2).
.
1H and 13C
Quang, D.N., Hashimoto, T., Nukada, M., Yamamoto, I., Tanaka,
M., Asakawa, Y., 2003b. Antioxidant activity of curtisians I–L from
the inedible mushroom Paxillus curtisii. Planta Medica 69, 1063–
1066.
3.3.5. Thelephantin M (5)
Yellow brown solid; Positive FAB-MS: 548 [M]+;
HR-FABMS m/z 548.1108 (C32H20O9, requires m/z
548.1107). UV lmax nm (log ꢁ): 229.8 (4.6), 265.8 (4.2),
299.2 (4.0), 321.8 (4.1), 329.4 (4.1). IR (KBr): 3221,
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