Abstract: In order to study the chemical composition and biological activity of the active substances from the seed of Ormosia hosiei Hemsl.Et Wils.,the gas chromatography-mass spectrometry (GC-MS) was used to analyze the chemical composition of methanol extraction.And we firstly extracted the biological active substances from the seed of O.hosiei Hemsl.Et Wils.by different polar solvents.Meanwhile,the antioxidant activity of the biological active substances was determined by free radical scavenging assays against 1,1-diphenyl-2-picrylhydrazine (DPPH) and 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) ( ABTS).And the antimicrobial activity was also examined by inhibition zone.Our results showed that twelve compounds representing 89.03% of the total constituents were identified from the extraction.The major compounds of the seed extraction were 5-Hydroxymethylfurfural (52.98%),aldehydo-D-allose (7.24%),2,3-Dimethoxy-10,11-dihydro-dibenzo(b,f)oxepin-10-ol (6.51%),O-methyleugenol (4.53%),4H-pyran-4-one,2,3-dihydro-3,5-dihydroxy-6-methyl-(4.45%),safrole (3.75%),(S)-(-)-α-terpineol (3.31%) and 2,6-Dimethoxyphenol (2.01%).All these eight components accounted for 84.78% of the total.The extraction of n-butanol,ethyl acetate,and petroleum ether from the seed of O.hosiei Hemsl.Et Wils.showed significant antioxidant activities against DPPH free radicals and ABTS free radicals,and the antioxidant activity was linearly correlated with the concentration.When the concentration of n-butanol,ethyl acetate,and petroleum ether extracts was 10.0 mg/mL,the n-butanol extracts had the best inhibitory effect on Escherichia coli,Pseudomonas aeruginosa,and Salmonella typhimurium.The ethyl acetate extract had the best bacteriostatic effect on Bacillus subtilis.Petroleum ether extract had the best antibacterial effect on Staphylococcus aureus and Bacillus thuringiensis.All these results provide data support for the development and comprehensive utilization of the seed resources of O.hosiei Hemsl.Et Wils..

Key words: seed of Ormosia hosiei Hemsl.Et Wils., volatile oil, chemical constituents, antioxidant activity, antibacterial activity