866
Communications to the Editor
Chem. Pharm. Bull. 53(7) 866—867 (2005)
Vol. 53, No. 7
from the young stems of the tea plant, Camellia sinensis (L.)
O. K. (Theaceae), cultivated in the Puncak area, West Java,
Indonesia, through the same procedure as described in our
previous paper.4)
Biooxidation of (ꢀ)-Catechin and (ꢁ)-
Epicatechin into 3,4-Dihydroxyflavan
Derivatives by the Endophytic Fungus
Diaporthe sp. Isolated from a Tea Plant
The Diaporthe sp. microbe was cultivated in glucose–
yeast extract–peptone medium (peptone 5.0 g, yeast extract
1.0 g, glucose 20 g, K2HPO4 0.5 g, MgSO4 0.5 g,
FeSO4·7H2O 0.01 g, CaCO3 1.0 g and tap water 1 l, pH 6.44)
at 27 °C for 5 d, and then a MeOH solution of (ꢀ)-catechin
(1) was added to the culture medium. After further cultiva-
tion for 1 d, the whole mixture was extracted with EtOAc,
which was purified by SiO2 column chromatography (eluted
Hirotaka SHIBUYA, ,a Andria AGUSTA,a
*
Kazuyoshi OHASHI,a Shoji MAEHARA,a and
b
Partomuan SIMANJUNTAK
a Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama
University; Sanzo, 1 Gakuen-cho, Fukuyama, Hiroshima 729–0292,
Japan: and b Research Centre for Biotechnology, Indonesian with CHCl3 : MeOH : H2Oꢂ65 : 35 : 10, lower phase) and
Institute of Sciences; Jalan Raya Bogor Km 46, Cibinong, Bogor
16911, Indonesia.
Received March 22, 2005; accepted April 28, 2005
subsequent reverse-phase HPLC with H2O to afford one bio-
transformed product (3, 45%) in addition to the recovered
(ꢀ)-catechin (1, 8.5%).
The IR and UV spectra of the product (3), C15H14O7, [a]D
ꢀ5.5° (EtOH), appeared to be the chemical derivative
of 1. Furthermore, the 1H-NMR spectrum (J2,3ꢂ9.5 Hz,
J3,4ꢂ3.7 Hz) suggested that 3 was (ꢀ)-2,3-trans-3,4-cis-
3,4,5,7,3ꢃ,4ꢃ-hexahydroxyflavan, which is a known com-
pound reported by Kristiansen.5,6) The tetramethyl derivative
of 1 was identical to the 2,3-trans-3,4-cis-type compound (5,
J2,3ꢂ10.1 Hz, J3,4ꢂ4.0 Hz), but not identical to the 2,3-trans-
3,4-trans-type compound (6, J2,3ꢂ10.3 Hz, J3,4ꢂ7.5 Hz and
the observed NOE between 2-H, 4-H), which were prepared
from (ꢀ)-(2R,3R)-3,5,7,3ꢃ,4ꢃ-pentahydroxyflavanone (4) by
the known procedure (CH2N2 and subsequent NaHB4 treat-
The microbial transformation of (ꢀ)-catechin (1) and (ꢁ)-
epicatechin (2) by endophytic fungi isolated from a tea plant
was investigated. It was found that the endophytic filamentous
fungus Diaporthe sp. transformed them (1, 2) into the 3,4-cis-di-
hydroxyflavan derivatives, (ꢀ)-(2R,3S,4S)-3,4,5,7,3ꢂ,4ꢂ-hexahy-
droxyflavan (3) and (ꢁ)-(2R,3R,4R)-3,4,5,7,3ꢂ,4ꢂ-hexahydroxy-
flavan (7), respectively, whereas (ꢁ)-catechin (ent-1) and (ꢀ)-
epicatechin (ent-2) with a 2S-phenyl group resisted the biooxi-
dation.
Key words microbial transformation; (ꢀ)-catechin; (ꢁ)-epicatechin;
endophyte; Diaporthe sp.; tea plant
Flavan-3-ols [(ꢀ)-catechin (1), (ꢁ)-epicatechin (2), (ꢁ)- ment)7) (Fig. 1).
epigallocatechin 3-O-gallate, etc.], which are typical chemi-
Through the same procedure as in the case of (ꢀ)-catechin
cal constituents of tea plants, are well known free-radical (1), the Diaporthe microbe transformed (ꢁ)-epicatechin (2)
scavengers.1,2) We predicted that endophytic microbes living into a product (7) in 39% conversion yield together with 2
inside tea plants might transform flavans into their chemical (2.4%). The IR and UV spectra of the product (7), C15H14O7,
derivatives. In this paper, we report the microbial transforma- [a]D ꢁ8.4° (EtOH), showed similar absorption bands to
1
tion of (ꢀ)-catechin (1) and (ꢁ)-epicatechin (2) by the endo- those of 3 transformed from (ꢀ)-catechin (1). The H-NMR
phytic filamentous fungus Diaporthe sp.3) which was isolated spectrum also showed a signal pattern like that of 3, except
Fig. 1
Fig. 2
∗ To whom correspondence should be addressed. e-mail: shibuya@fupharm.fukuyama-u.ac.jp
© 2005 Pharmaceutical Society of Japan