Objective: To deeply study the major chemical compounds and their bioactivities of the underground part of Isodon flavida. Method: The samples were isolated and purified by using silica gel

Sephadex LH-20

and MCI chromatographic techniques. The structures of the monomer compositions were determined based on modern spectrum technology and physicochemical properties. In addition

the antioxidant and antimalarial activities of the samples were tested by using 1

1-diphenyl-2-picrylhydrazyl radical 2

2-diphenyl-1-(2

4

6-trinitrophenyl)hydrazyl(DPPH) method and β-hematin formation inhibition method. Result: Nine compounds were obtained from n-butanol fraction of 70% acetone extract of the underground part of I. flavida

and identified as 2

6-dimethoxybenzoquinone (1)

methyl rosmarinate (2)

2α-hydroxyoleanolic acid (3)

1-methoxy-α-D-glucose (4)

1-methoxy-β-D-glucose (5)

sucrose (6)

adenanthoside C (7)

5α

6β-dihydroxydaucosterol (8)

and (2'R)-1-O-glyceryl-6-O-α-D-galactopyran-osyl-β-D-galactopyranoside (9). Bioactive studies indicated that compound 2 showed certain clearing effect on DPPH and inhibitory effect on β-hematin formation

with IC50 values of (124.2±2.7)

(163.9±7.5) mg · L-1

respectively. Conclusion: All of the 9 compounds were isolated from the plant for the first time. Compound 2 showed certain antioxidation and antimalaria effects

which deserved further investigation. This study provided certain experimental basis for the development and utilization of Isodon plants.