Objective: To study the chemical constituents of fructus Melia toosendan. Method: Normal phase silica gel

RP-18 Silica gel and Sephadex LH-20 column chromatographies combined with recrystallization were used to isolate and purify the constituents. Their structures were identifided by spectroscopic methods

including 1H-NMR

13C-NMR

ESI-MS and EI-MS. Result: Twelve compounds were isolated. Their structures were decided as 1-O-tigloyl-1-O-debenzoylohchinal (1)

ohchinal (2)

1-cinnamoyltrichilinin (3)

3

7-diacetyl-14

15-deoxyhavanensin (4)

7-O-acetyl-14

15-deoxyhavanensin (5)

6α-O-acetyl-7-deacetylnimocinol (6)

6α-hydroxyazadirone (7)

24-nor-5ξ-13α

17α-chola-14

20

22-triene-3β

7α-diol-21

23-epoxy-4

4

8-trimethyl-3-acetate (8)

hedyotol-A (9)

2

6-bis(3-methoxy-4-hydroxyphenyl)-3

7-dioxabicyclo[3

3

0]octan-8-one (10)

exo-endo-2

6-bis(4'-hydroxy-3'-methoxy-phenyl)-3

7-dioxabicyclo[3

3

0]octane (11) and betulafolienediolone (12). Conclusion: Compounds 2-12 were obtained from fructus M. toosendan for the first time.