Objective To isolate and extract the antilipopolysaccharide (LPS) active compounds from Scutellaria baicalensis Georgi.  Methods A series of fractions was prepared by macroporous adsorptive resins and HPLC from the aqueous extract of the herb. Their binding activity to lipid A and the neutralization to LPS were detected by the biosensor technology and kinetic turbidimetric limulus test. The active compounds against LPS were screened. RT-PCR and ELISA was used respectively to detect the expression of TLR4 mRNA and measure the release of TNF-α in RAW264.7 cells exposure to LPS (100 μg/L) with or without the screened compound pretreatment.  Results Five HPLC products were isolated from the herb and named from S3K1 to 5. Among them

S3K1 had the highest bind activity to lipid A and significantly inhibited the coagulation reaction induced by LPS (0.2 μg/L) at the dose of 2.0 mg/L. The expression of TLR4 mRNA was increased after the cells exposure to LPS

however

this effect was attenuated by the pretreatment with S3K1 in doses of 40

80

160 mg/L. The supernatant TNF-α level was significant decreased in a negatively dose-dependent manner when S3K1 was used to treat the cells before LPS stimulation.  Conclusion An active anti-LPS compound

S3K1 is attained from Scutellaria baicalensis Georgi

which neutralizes LPS

inhibits the expression of TLR4 mRNA and suppresses the activity of RAW264.7 cells after exposure to LPS.