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H. KENMOKU et al.
weight: 360.2301). Its spectral data were as follows.
EIMS m=z (%): 360[Mþ, 55], 345(37), 317(19),
300(24), 285(51), 282(36), 272(42), 257(68), 231(48),
203(100), 189(97), 175(70); IR ꢄmax (film) cmꢀ1: 1743,
1672; the 1H- and 13C-NMR data are shown in Table 1.
Its 1H-NMR spectrum showed similar signals to those of
3, except for the absence of the hydroxymethine signal
of H-14. The 13C-NMR signal (ꢂ 209.7 in Table 1) and
IR band (ꢄC=O: 1672 cmꢀ1) revealed 2 to have a
conjugated carbonyl group in the molecule. These
observations suggested that 2 was the 14-oxo-derivative
of 3. This was sufficiently supported by comparing the
13C-NMR data between 2 and O,O-diacetylcyathin A3,
the latter has been chemically derived from 11,15-O,O-
diacetylcyathatriol and cyathin A3.6,8–10) The 13C-NMR
signals of 2 were in good agreement with those of O,O-
diacetylcyathin A3, except for the acetylation-shifted
carbons at 12, 13 and 14 (ꢀ4.1, 1.5 and 1.0 ppm,
respectively). The structure of 2 was thus identified as
11-O-acetylcyathin A3. Its 1H- and 13C-NMR signals
(Table 1) were fully assigned by H–H and C–H COSY,
and HMBC methods.
Cyatha-3,12-dien-14ꢀ-ol (1) and 11-O-acetylcyathin
A3 (2) are new fungal metabolites from erinacine Q-
producing H. erinaseum YB4-6237. In particular, 1 is
not only a novel monohydroxy cyatha-3,12-diene, but
also a putative intermediate in the biosynthesis of the
erinacine Q aglycon. This suggests that the 14ꢀ-
hydroxyl was introduced first in three hydroxyls of the
erinacine Q aglycon. 11-O-Acetylcyathatriol (3) as the
erinacine Q aglycon was newly isolated from the
mycelial extract of the basidiomycete and spectroscopi-
cally identified. Possible biosynthetic relationships of
these metabolites to erinacine Q on the basis of the
observations described here are shown in Fig. 1. 1 and 2
as important metabolites in the erinacine Q-biosynthetic
pathway between (ꢀ)-cyatha-3,12-diene and parental
erinacine Q in erinacines were revealed in this study. 2
being an oxidation metabolite of 3 of the erinacine Q
aglycon. 4 as the positional isomer of the acetyl group in
3 is considered to have been an artifact derived from 3.
We are now investigating the biosynthetic pathway of
erinacine Q in the basidiomycete on the basis of
incorporation experiments on labeled 1 and 2 to
erinacine Q and its aglycon, and the isolation and
structural determination of other hydroxycyathadiene
metabolites.
Fig. 2. Stereostructure and Conformation of Erinacol (1).
chloride in a mixture of 1:1 ethyl ether/pyridine. EIMS
m=z (%): 392[Mþ, 0.4], 377(2), 270(99), 105(100); UV
ꢃmax (EtOH) nm ("): 232 (16,800); ꢂH (400 MHz,
CDCl3): 4.91 (1H, d, 7.6; H-14), 7.46 (2H, d, H-20)
7.57 (1H, dd, 7.8, 7.8, H-30), and 8.12 (2H, d, 7.8, H-10).
The benzoate showed a positive Cotton effect ðꢀ" þ
3:2Þ at 234 nm, indicating the configuration at the C-14
position to be S.7) The absolute stereostructure of 1 was
thus determined to be cyatha-3,12-dien-14ꢀ-ol (Fig. 2);
its configuration at C-14 was the same as that of the
aglycon of erinacine Q.
25
3, ½ꢁꢂD ꢀ37ꢁ (c 0.26, CHCl3), had the molecular ion
peak at m=z 362.2457 in the HR-EIMS data, indicating
the molecular formula of C22H34O4 (Calcd. molecular
weight: 362.2457). Its 1H-NMR spectrum showed many
signals closely resembling those of the aglycon moiety
of erinacine Q.4) Furthermore, the 13C-NMR signals
(Table 1) of 3 were in good agreement with those of the
erinacine Q aglycon, 11-O-acetylcyathatriol, which has
been isolated from basidiomycetous Cyathus earlei by
Ayer et al.6) Although its ½ꢁꢂD value has not been
reported in the literature, 3 and erinacine Q showed
almost same CD spectra, having a negative Cotton effect
at 207 nm. The structure of 3 was thus identified as 11-
O-acetylcyathatriol. The 1H and 13C-NMR signals
(Table 1) of 4 were basically similar to those of 3.
17
These data, together with the ½ꢁꢂD value of 4 {½ꢁꢂD ꢀ9ꢁ
(c 0.11, CHCl3)} were in good agreement with those of
15-O-acetylcyathatriol, which has also been isolated
from C. earlei6) and was the positional isomer of the
acetyl group of 3. 3 in a methanolic Na2CO3 solution
(4 mM) at room temperature gave 4 together with a small
amount of cyathatriol, suggesting that 4 was an artifact
formed during the preparation of the basic and neutral
substances from the mycelial extract of H. erinaceum
YB4-6237.
Acknowledgments
The authors thank Messrs. Eiichi Kimura and Takashi
Shigihara at Edible Fungi Institute of Kinox Co., Ltd.,
for providing H. erinaceum YB4-6237. This work was
partially supported by the Ministry of Education,
Culture, Sports, Science and Technoloby of Japan
though grant-aid for scientific research (no. 13306009).
16
2, ½ꢁꢂD ꢀ56ꢁ (c 0.12, EtOH), had the molecular ion
peak at m=z 360.2297 in the HR-EIMS data, indicating
the molecular formula of C22H32O4 (Calcd. molecular
Kenmoku, Hiromichi
