Objective: To identify the suitable extraction method and polarity for estrogenic active substance in Selaginella tamariscina (Beauv.)Spring

through the estrogenic active screening of different extracts of Selaginella tamariscina from different extraction methods. Methods: Selaginella tamariscina was extracted by 70% ethanol to obtain the total fraction

the total fraction was separated by polyamide column to obtain the water fraction、50% ethanol and 80% ethanol fractions; Selaginella tamariscina was refluxed by 95% ethanol to obtain the 95% ethanol extract

and the residue was decocted by water to obtain the residue water extract; the residue water extract was removed polysaccharides to obtain non-polysaccharides part of water-soluble components. Then adopt the uterine weight method in mice to detect the estrogenic activity of all these different extracts. The 95% ethanol extract and the residue water extract were analysised by high-performance liquid chromatography (HPLC) fingerprint. Results: Compared with the control group

the total fraction、high dose of the residue water extract and non-polysaccharides part of water-soluble components group significantly increased uterus coefficient (p<0.01)

while the other groups of Selaginella tamariscina showed no significantly effects (p>0.05); HPLC fingerprint demonstrated that amentoflavone was the main component of the 95% ethanol extract

but no amentoflavone was observed in the residue water extract. Conclusion: The extraction method of 95% ethanol refluxing and the residue water decocting was more suitable for extracting the estrogenic active substance of Selaginella tamariscina; the non-polysaccharides part of water-soluble components play an important role in estrogen activity in Selaginella tamariscina; HPLC fingerprint result suggested that amentoflavone was not the estrogenic active component of Selaginella tamariscina.