Research: SHIIZAKI and colleagues,

Listed in Issue 65


SHIIZAKI and colleagues, Kampo and Pharmacognosy Laboratories, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan. have established a highly sensitive bioassay system aimed at measuring oestrogen activity in Chinese herbal medicines.


Plants contain substances with oestrogen activity referred to as phytoestrogens, comparable to those in animals where oestrogens are steroid hormones. Phytoestrogens may be responsible in part for the effects of Chinese herbal prescriptions for postmenopausal disorders. Oestrogen activity in herbal medicine is considered extremely important for patients in whom oestrogen administration is contraindicated.


The most important action of oestrogen is the transcriptional regulation of specific genes via oestrogen receptors (ER). The investigators therefore established a highly sensitive bioassay system by placing oestrogen-responsive elements (ERE) upstream to the reporter gene, and used this assay to determine the oestrogen activity in herbal medicines.


Phytoestrogens were found in many Chinese herbal prescriptions for postmenopausal disorder.


Some prescriptions were considered to effectively administer hormone replacement therapy (HRT). However, since oestrogen activities in most Chinese herbal preparations were thought to be weak, it was considered that these prescriptions improved postmenopausal disorder via a mechanism different to that of oestrogen replacement therapy.


Shiizaki K et al. Bioassay of phytoestrogen in herbal medicine used for postmenopausal disorder using transformed MCF-7 cells. Phytotherapy Research 13 (6): 498-503. Sep 1999.


See also Kate Neil’s article Phytoestrogens Re-examined in this issue, page 28. Chinese herbs have played an important role in the management of menopausal symptoms. This type of research is valuable in that it dissects out the mechanisms of active of these herbs.

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