Abstract: The chemical constituents of the essential oil from Ligusticum chuanxiong were separated and purified by various chromatographic techniques including silica gel and Sephadex LH-20 column chromatography,normal phase(NP) semi-preparative HPLC and reversed phase (RP) semi-preparative HPLC.Their structures were identified by physicochemical properties,spectroscopic analysis,as well as comparison with the literature data.PC12 cells injured by CoCl₂ were used as the cell model of hypoxia.The viability and lactate dehydrogenase(LDH) release of PC12 cells were separately detected by MTT assays and LDH detecting kits,and the apoptotic cells were stained by Hoechst 33258.Six compounds were isolated from the essential oil of L.chuanxiong  and identified asriligustilide (1),endo-Z,Z′-(3a.7a′,7a.3a′)-diligustilide(2),spathulenol (3),(E)-3-butylidenephthalide(4),3-butylidene-7-hydroxyphthalide(5),and senkyunolide I(6).It was proved that the oil and compound 1 (riligustilide) protected the injury and inhibit the apoptosis induced by CoCl₂ in PC12 cells,and reduced the level of LDH in cells.These results demonstrated that the essential oil of L.chuanxiong and compound 1 (riligustilide) had protective effect for injured neurons in appropriate concentration range,and provided scientific reference for pharmacodynamic material basis of L.chuanxiong.  

Key words: Ligusticum chuanxiong, essential oil, chemical constituents, protective effect on PC12 cells