Phytoestrogenic activity of Sophora flavescens extract and its constituents

Sophora flavescens Ait. is monographed in the Chinese Pharmacopoeia as Radix Sophorae flavescentis (Kushen) [1]. The crude drug is traditionally used for the treatment of diarrhoea, gastro-intestinal haemorrhage and eczema. S.flavescens roots contain quinolizidin alkaloids, non-glycosidic flavones, and triterpene glycosides. Although some of the flavones found in this medicinal plant hint to potential estrogenic properties, surprisingly, still up to now, very few reports on the estrogenic activity of extracts from this drug have been published [2]. Due to the presence of the alkaloids, S. flavescens roots have some toxic potential. Thus, we have engaged in the development of a special extract from this drug which is characterized by the absence of alkaloids [3]. This extract was tested for estrogenic activity in a panel of suitable test models. Besides a significant competitive binding to estrogen receptors alpha (ER alpha) and ER beta, induction of alkaline phosphatase in Ishikawa endometrial adenocarcinoma cell was observed. Unfortunately, the extract did not display any estrogen receptor selectivity and promoted uterine growth in ovariectomized rats. Hence, it was considered inappropriate for the treatment of climacteric complaints and precluded from further product development.

Keywords: Sophora flavescens, antiestrogenic activity

References: 1. Kuang L, Zhang K (2005) Pharmacopoeia of the Peoples Republic of China, Vol.I, People's Medical Publishing House, Beijing.

2. Hillerns PI, Wink M (2005) Planta Med 71: 1065.

3. Dr. Willmar Schwabe GmbH & Co., European Patent EP 1294388 B1 (granted 2004)