Objective: To identify the suitable extraction method and polarity for estrogenic active substance in Selaginella tamariscina

through the estrogenic active screening of different extracts of S. tamariscina from different extraction methods. Method: 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; S.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 the uterine weight method in mice was adopted to detect the estrogenic activity of all these different extracts. The 95% ethanol extract and the residue of water extract were analyzed by high-performance liquid chromatography (HPLC) fingerprint. Result: Compared with the control group

the total fraction

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

while the other groups of S. 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 S. tamariscina; the non-polysaccharides part of water-soluble components played an important role in estrogen activity in S. tamariscina; HPLC fingerprint suggested that amentoflavone was not the estrogenic active component of S. tamariscina.