The invention discloses application of a
caragana crude extract and an n-
butanol layer extract in antituberculous activity and preparation methods of the
caragana crude extract and the n-
butanol layer extract, and the preparation method of the
caragana crude extract comprises the following steps: weighing dried and crushed caragana roots, adding 90% absolute ethyl
alcohol with the same volume as the caragana roots, extracting by adopting a heating
reflux extraction method, and concentrating under reduced pressure to obtain the caragana crude extract. Sequentially extracting with
petroleum ether,
dichloromethane and n-butyl
alcohol to obtain caragana
petroleum ether layer extract,
dichloromethane layer extract and n-butyl
alcohol layer extract; tests prove that the caragana crude extract and the caragana n-butyl alcohol layer extract have remarkable bacteriostatic activity on
mycobacterium smegmatis, have a strong bacteriostatic effect on a
mycobacterium tuberculosis standard strain H37Rv (ATCC27294) and have certain bacteriostatic activity on a multidrug-resistant
tubercle bacillus strain Mtb706, and by means of activity-oriented extraction
process optimization, the content of the caragana n-butyl alcohol layer extract is greatly improved. The screening range of the antituberculous active ingredients in the caragana roots is effectively narrowed, and a key foundation is laid for the subsequent separation and purification of the active ingredients and the research on the action mechanism.