独山瓜馥木促进休眠型结核杆菌复苏的成分和作用机制初探

摘要

Compound 1,with resuscitating activity on dormant Mycobacterium tuberculosis,was isolated from Fissistigmacavaleriei root by bioassay-guided method.It was identified asβ-sitosterol-9,12-hexadecadienoate by physical and spectroscopic methods.Compound 1 showed activity to resuscitate dormant Mycobacterium tuberculosis into active state in a dose-dependent manner with minimum effective concentration of 16 μg/mL.Dormant M.tuberculosis was insensitive to isoniazid,ethambutol,rifamicin and pyrazinamide in single drug.At the concentration of 32 μg/mL,Compound 1 canhelp isoniazid to kill dormant M.tuberculosisafter 14 and 21 days of exposure,and increase the killing activity of rifamicin against dormant M.tuberculosis.However,among two-drug combinations,compound 1-ethambutol andcompound 1-pyrazinamide,exhibited antagonistic action on dormant M.tuberculosis.Compound 1 can activate the KatG activity of dormant M.tuberculosis,which caused the content of O2 in dormant M.tuberculosis cells at a high level to trigger the resuscitation of dormant M.tuberculosis.%采用活性跟踪分离方法,从独山瓜馥木分离得到能促进休眠型结核杆菌复苏的化合物1,鉴定为β-谷甾醇-9,12-十六碳二烯酸酯.化合物1在浓度为16 μg/mL时开始显示促复苏活性,呈明显的量效关系.异烟肼、乙胺丁醇、利福平和吡嗪酰胺单独用药时,不能杀死休眠型结核杆菌,化合物1(32 μg/mL)与异烟肼联合用药,培养14、21 d后检测,休眠型结核杆菌被杀死,化合物1可增强利福平对休眠菌的杀灭作用,但分别与乙胺丁醇和吡嗪酰胺联合时,均表现为拮抗作用.化合物1能激活休眠型结核杆菌的KatG酶,使细胞内O2含量升高,导致休眠型结核杆菌复苏.