Author/Authors :
Erasto، P. نويسنده National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania. , , Omolo، J. نويسنده National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania. , , Hamilton، C. نويسنده School of Pharmacy, University of East Anglia, Norwich NR47TJ, United Kingdom. , , Koning، C.d. نويسنده Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits 2050, Johannesburg, South Africa. ,
Abstract :
The phytochemical analysis on the root wood of Teclea amaniensis afforded a quinoline alkaloid veprisine. Its chemical structure was deduced using Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) analyses. Veprisine was screened for antimycobacterial activity against two mycobacterial strains namely; Mycobacterium madagascariense (MM) DSM 44641 and Mycobacterium indicus pranii (MIP) DSM 45239. It exhibited moderate to higher antimycobacterial activity against test organisms with the MIC values of 657.9 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 to determine its ability to potentiate the activity of isoniazid against the two resistant mycobacteria strains. The assay was done by screening the combination of 1/2 to 1/16 MIC values of veprisine and isoniazid (adopted MIC values of INH against M. tuberculosis Mtb H37Rv strain). Veprisine potentiated the activity of INH against MM and MIP with fractional minimum inhibitory concentration (FMIC) values of 328 µM and 164 µM respectively. The FMIC values are equivalent to 1/2 and 1/16 MIC values of veprisine against MM and MIP respectively. When INH and veprisine were tested alone within this range, they lacked efficacy against the test organisms. These results show that veprisine is bioactive against Mycobacterium species and it has the ability to potentiate the activity of isoniazid against resistant strains.
