E.O. Igumbor

In vitro activity of three selected South African medicinal plants against human immunodeficiency virus type 1 reverse transcriptase

Crude extracts of three ethnobotanically selected medicinal plants were screened for activity against two functions of human immunodeficiency type 1 reverse transcriptase. Inhibition of the RNA-dependent DNA polymerase activity was evaluated by measuring the degree of incorporation of methyl-3H thymidine triphosphate using polyadenylic acid.oligodeoxythymidylic acid as a template primer. Ribonuclease H activity was evaluated by measuring the extent of degradation of a radiolabelled RNA in an RNA/DNA hybrid by reverse transcriptase in the presence of test substance. The methanol extract of the leaves of Terminalia sericea (Combretaceae) was found to strongly inhibit the polymerase (IC 50 = 7.2 µg/ml) and the ribonuclease H (IC 50 = 8.1 µg/ml) activities. Isolation and characterization of a possible active molecule is warranted. Key Words: HIV-1 reverse transcriptase; inhibition; crude extracts; medicinal plants; Terminalia sericea ; South Africa. African Journal of Biotechnology Vol.3(10) 2004: 555-559

Prevalence and temporal distribution of Schistosoma haematobium infections in the Vhembe district, Limpopo Province, South Africa.

Although the delayed-type hypersensitivity (DTH) skin reaction to tuberculin is used worldwide for tuberculosis (TB) detection, it has poor diagnostic specificity due to the presence of common antigens in tuberculin shared by many mycobacterial species. The problem is noticed, especially in countries where the Bacillus Calmette-Gue´rin (BCG) vaccination is widely practiced. Thus, a new skin test antigen specific for the diagnosis of Mycobacterium tuberculosis (MTB) infection is urgently needed. CFP-10, a mycobacterial secretary protein that is absent in Mycobacterium bovis BCG and most other mycobacterial species including Mycobacterium avium, Mycobacterium intracellulare, has been shown to elicit cellular immune responses in MTB infected individuals and can be a good candidate for MTB specific diagnosis. We prepared recombinant MTB CFP-10, rCFP-10, and its utility as specific antigen for TB diagnosis was evaluated by skin testing in guinea pigs sensitized with M . tuberculosis, M. bovis, and M. bovis BCG. Our results show that the purified MTB rCFP-10 antigen elicits a positive skin response only in the guinea pigs sensitized with M. tuberculosis and M. bovis , and not in the animals sensitized with M. bovis BCG vaccine. The data presented in this study supports further testing of the use rCFP-10 as the specific antigen in the skin test for the diagnosis of MTB infection in humans. Key words : Recombinant CFP-10 protein, skin test, delayed-type hypersensitivity, tuberculosis infection, Mycobacterium tuberculosis, Mycobacterium bovis, Bacillus Calmette-Gue´rin.