Antimycobacterial quinoline alkaloid from the root wood of teclea amaniensis engl.

Thephytochemical analysis on the root wood of Tecleaamaniensis afforded a quinoline alkaloid veprisine. Its chemical structurewas deduced using Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) analyses.Veprisine was screened for antimycobacterial activity against two mycobacterialstrains namely; Mycobacterium madagascariense (MM) DSM 44641 and Mycobacterium indicus pranii (MIP) DSM 45239. It exhibited moderate tohigher antimycobacterial activity against test organisms with the MIC values of657.9 µM and 2.63 x 103 µM against MM and MIP respectively.In the same assay isoniazid (INH), a first line anti-TB drug lacked efficacy,even at higher concentration. Consequently, veprisine was further screened todetermine its ability to potentiate the activity of isoniazid against the tworesistant mycobacteria strains. The assay was done by screening the combinationof 1/2 to 1/16 MIC values of veprisine and isoniazid (adopted MIC values of INHagainst M. tuberculosis Mtb H37Rvstrain). Veprisine potentiated the activity of INH against MM and MIP withfractional minimum inhibitory concentration (FMIC) values of 328 µM and 164 µMrespectively. The FMIC values are equivalent to 1/2 and 1/16 MIC values ofveprisine against MM and MIP respectively. When INH and veprisinewere tested alone within this range, they lacked efficacy against the testorganisms. These results show that veprisine is bioactive against Mycobacterium species and it has theability to potentiate the activity of isoniazid against resistant strains.