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Antimicrobial Agents and Chemotherapy, June 2005, p. 2501-2503, Vol. 49, No. 6
0066-4804/05/$08.00+0 doi:10.1128/AAC.49.6.2501-2503.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
Biosynthesized Tea Polyphenols Inactivate Chlamydia trachomatis In Vitro
Tsutomu Yamazaki,1,2*
Toshio Kishimoto,1
Sadashi Shiga,1
Kozue Sato,1
Toshikatsu Hagiwara,1
Miyuki Inoue,2
Nozomu Sasaki,2
Kazunobu Ouchi,3 and
Yukihiko Hara4
Department of Virology 1, National Institute of Infectious Diseases, Tokyo,1
Department of Pediatrics, Saitama Medical School, Saitama,2
Department of Pediatrics 2, Kawasaki Medical School, Kurashiki,3
Food Research Laboratories, Mitsui Norin Co., Shizuoka, Japan4
Received 2 September 2004/
Returned for modification 23 November 2004/
Accepted 4 February 2005

ABSTRACT
Biosynthesized tea polyphenols showed antichlamydial activity
against
Chlamydia trachomatis D/UW-3/Cx and L
2/434/Bu using
cell culture. The most active compounds were ()-epigallocatechin
gallate and ()-epicatechin gallate, followed by ()-epicatechin
(EC). (+)-Epicatechin and ()-epigallocatechin were intermediate.
EC was the least toxic. These results warrant evaluation of
tea polyphenols as topical antichlamydial agents.

TEXT
Chlamydia trachomatis is one of the most common causes of sexually
transmitted diseases (
5). Results obtained with topical antichlamydial
agents such as nonoxynol-9 (
3,
8,
10), monocaprin (
4), C31G
(
14), cecropin peptides (
1), and protegrins (
17) have been reported.
Disinfectants containing products such as chlorhexidine gluconate
gel (
9) and the spermicide benzalkonium chloride (
2) have also
been shown to inactivate
C. trachomatis. We have previously
reported that tea extracts have antichlamydial activity in vitro
and that the active compounds are polyphenols (
16).
Five tea polyphenols (Fig. 1), (+)-catechin (Catech), ()-epicatechin (EC), ()-epigallocatechin (EGC), ()-epicatechin gallate (ECg), and ()-epigallocatechin gallate (EGCg), were tested in this study. These chemicals were biosynthesized naturally and supplied by Mitsui Norin Co., Ltd. (Tokyo, Japan).
The chlamydial strains tested were
C. trachomatis D/UW-3/Cx
and L
2/434/Bu. HeLa 229 cells were used for growing
C. trachomatis.
A preinoculation minimal cidal concentration method, previously
described by Lampe et al. (
9), was used to test the in vitro
susceptibility of
C. trachomatis to tea polyphenols. A total
of 1 ml of culture medium containing 2
x 10
5 HeLa 229 cells
per ml was dispensed into each well of a plastic 24-well culture
plate and incubated in 5% CO
2 at 37°C for 24 h to form a
confluent monolayer. Then, 1.0
x 10
4 inclusion-forming units
of
C. trachomatis were incubated with serial dilutions of tea
polyphenols at 35°C for 90 min. Controls were incubated
with sucrose phosphate glutamate (SPG) buffer containing no
test compounds. Pretreated inocula were centrifuged onto the
cells at 1,500 rpm for 60 min. After centrifugation, the inocula
were removed. Culture medium containing no tea polyphenols was
added and incubated for 72 h. Eagle's minimum essential medium
containing 10% fetal calf serum and 0.6 µg/ml cycloheximide
was used as the culture medium. The cells were fixed with methanol
and stained with fluorescein isothiocyanate-conjugated antichlamydial
monoclonal antibody (Denka Seiken Co., Ltd., Tokyo, Japan).
Inclusions were counted by a fluorescent microscope. At least
three wells per dilution were tested, and each experiment was
repeated at least three times.
The toxic effects of EC, ECg, and EGCg on HeLa 229 cells were examined by using a CK01 cell counting kit (Dojindo Laboratory Co., Ltd., Kumamoto, Japan), a colorimetric assay for cell proliferation and viability. Cell activity was determined according to the manufacturer's instructions. Briefly, serial dilutions of tea polyphenols in SPG buffer were dispensed into 96-well microtiter plates containing a monolayer of HeLa 229 cells and incubated for 60 min at 35°C. After removal of tea polyphenols, cell activity was determined. After being fixed with methanol and stained using Giemsa stain, the condition of the cells was assessed using a microscope. The integrity of the cell monolayer and morphological changes in the cells, such as a round shape, were evaluated.
All tea polyphenols tested had an inhibitory effect on chlamydial proliferation (Table 1). ECg and EGCg completely inhibited the proliferation of C. trachomatis serovar D at concentrations of 1.6 and 0.8 mg/ml, respectively. Complete inactivation was also noted for C. trachomatis serovar L2 after incubation with EC, ECg, and EGCg at concentrations of 0.4, 0.4, and 0.8 mg/ml, respectively.
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TABLE 1. Inhibitory effect of tea polyphenols on serovars D/UW-3/Cx and L2/434/Bu of C. trachomatis in the preinoculation minimal cidal concentration method
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The activity of HeLa 229 cells incubated with EC, ECg, and EGCg
is shown in Fig.
2. After 60 min of incubation with 0.4 mg/ml
EC, cell activity did not decrease and no differences in the
condition of the cells were observed after Giemsa staining.
By contrast, after 60 min of incubation with increasing concentrations
of ECg and EGCg, the activity of HeLa 229 cells decreased and
at high concentrations of ECg and EGCg the cells had a round
shape.
Tea polyphenols have been shown to have in vitro antimicrobial
effects (
6,
11-
13,
15). We previously reported that Polyphenon
70S, a mixed compound of tea polyphenols, had an in vitro inhibitory
effect on
C. trachomatis (
16). Polyphenon 70S is composed of
EGCg, EGC, ECg, EC, and ()-gallocatechin gallate. Each
individual constituent had an inhibitory effect at a lower concentration
than that in Polyphenon 70S: the endpoint for
C. trachomatis serovar D was 1.6 mg/ml when incubated with Polyphenon 70S and
0.8 mg/ml when incubated with EGCg. These data suggest that
the individual constituents of tea polyphenols, such as EC,
are potential candidates for antichlamydial drugs.
The concentration of tea polyphenols required for complete inhibition of chlamydial proliferation is relatively high compared with the MIC of antibiotics such as tetracyclines, macrolides, and fluoroquinolones (16). Therefore, oral administration of tea polyphenols is not suitable for treating systemic infection. Each tea polyphenol constituent might be used topically. The development of more-effective drugs for systemic use by modifying the structures of EC, ECg, and EGCg is expected in the future.
Nonoxynol-9 is an active spermicidal ingredient used in a wide variety of vaginal contraceptive preparations. Products containing nonoxynol-9 also inhibit the growth of C. trachomatis. Lampe et al. indicated that a chlorhexidine gluconate gel could remain in the vagina for hours after topical application and provided protection against C. trachomatis infection for that time period (9). Addition of tea polyphenols to contraceptive jelly could have potential clinical use in the prevention of cervical infection caused by C. trachomatis. Of note, EC was the least toxic among the tea polyphenols that inactivated chlamydial strains. Further studies are required to clarify the safety of tea polyphenols for clinical usage.
Ikigai et al. indicated that EGCg damaged bacterial membranes (7). The inhibitory mechanisms of tea polyphenols against C. trachomatis are unknown and should be investigated further.

FOOTNOTES
* Corresponding author. Mailing address: Department of Virology 1, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku, Tokyo, Japan 162-8640. Phone: 81-3-5285-1111. Fax: 81-3-5285-1208. E-mail:
tochaben{at}gray.plala.or.jp.


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Antimicrobial Agents and Chemotherapy, June 2005, p. 2501-2503, Vol. 49, No. 6
0066-4804/05/$08.00+0 doi:10.1128/AAC.49.6.2501-2503.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.