Abstract: Residue of Eucommia ulmoides leaves, after being processed for pharmaceutical ingredients, was used to extract Eucommia gum. Both of solvent extraction of Eucommia gum, with pretreatment of E. ulmoides leaf residue by alkali hydrolysis and enzymatic hydrolysis separately, and direct extraction were studied. The optimum process condition was that: E. ulmoides leaf residue was mixed with n-hexane by a material to solvent ratio of 1:20 (g:mL), reflux extraction was applied at a high temperature for 2 h. Filtrate was put in freezer for 1 h at -20 ℃ for cooling crystallization, and then vacuum filtered and naturally dried to obtain the product of light green Eucommia gum. The yield was 4.42%. White Eucommia gum was obtained after multiple times of refining by acetone. The infrared spectrum of white Eucommia gum was measured, It was identified as trans-1, 4-polyisoprene (TPI).

Key words: Eucommia ulmoides leaf, Eucommia gum, extraction