Objective: To study the active components for antimicrobial activity in stems and leaves of Scutellaria baicalensis. Method: The components were extracted by using 60%ethanol cold immersion method

isolated and purified by silica gel chromatography

polyamide chromatography

Sephadex LH-20 column and HPLC

recrystallization and other methods. Their chemical structures were identified on the basis of physicochemical properties and spectral analysis (1H-NMR

13C-NMR

UV and MS). Result: Eight monomeric compounds were isolated from 60%ethanol extracts for stems and leaves of S. baicalensis

and their structures were identified as carthamidin-7-O-β-D-gluclronide (1)

5

4'-dihydroxy-7-methoxyflavanone (2)

genkwanin (3)

oroxylin-A-7-O-β-D-gluclronide(4)

7-methoxychrysin (5)

chrysin (6)

3'

4'

5

5'

7-pentamethoxyflavone (7)

and carthamidin-7-O-β-D-gluclronide (8). Conclusion: Compound 3 was isolated from stems and leaves of the plant for the first time. Compounds 2

5

7 were isolated from this plant for the first time.