Antimycobacterial triterpenoids from Lantana hispida (Verbenaceae).

As the Mycobacterium tuberculosis strains resistant to multiple drugs are increasing at an alarming rate, there is an urgent need for alternative anti-tuberculosis drugs. In a bioassay-guided search for antimycobacterial compounds obtained from higher plants, the study of the hexane extract from the aerial parts of Lantana hispida was performed and the biological activity of the plant products were tested against Mycobacterium tuberculosis H37Rv strain by microdilution alamar blue assay. Activity of the primary fractions led to the isolation of three pentacyclic triterpenoids with oleanane nucleous, together with beta-sitosterol. The molecular structures of the compounds were characterized as 3-acetoxy-22-(2'-methyl-2Z-butenyloxy)-12-oleanen-28-oic acid (1), 3-hydroxy-22 beta-(2'-methyl-2Z-butenoyloxy)-12-oleanen-28-oic acid (reduced lantadene A) (2) and oleanolic acid (3). MIC values for compounds 1 and 2 were 50 microg/ml, and for compound 3 the MIC=25 microg/ml.