title: Determination and quantification of the in vitro activity of Aloe marlothii (A. Berger) subsp. marlothii and Elephantorrhiza elephantina (Burch.) skeels acetone extracts against Ehrlichia ruminantium.
abstract: An Ehrlichia ruminantium culture system was utilized for the anti-rickettsial evaluation of two ethnoveterinary plants, Elephantorrhiza elephantina and Aloe marlothii. Well-established E. ruminantium cultures were incubated with the plant leaf acetone extracts and compared to oxytetracycline and untreated controls. Effectivity was established by comparing the percentage parasitised cells and the calculation of both EC50 and extrapolated EC90 in microg/ml. The plant extracts were also screened for antibacterial activity using bioautography. Elephantorrhiza elephantina and A. marlothii demonstrated anti-ehrlichial activity with an EC50 of 111.4 and 64.5 microg/ml and EC90 of 228.9 and 129.9 microg/ml, respectively. The corresponding EC50 and EC90 for oxytetracycline was 0.29 and 0.08 microg/ml. Both plants appeared to produce their inhibitory activity by a similar mechanism, unrelated to that of the tetracyclines. Both the plant acetone extracts demonstrated antibacterial activity against Escherichia coli and Staphylococcus aureus (ATCC strains).
authors.affiliation: Section of Pharmacology and Toxicology, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
authors.forename: V
authors.initials: V
authors.lastname: Naidoo
authors.forename: E
authors.initials: E
authors.lastname: Zweygarth
authors.forename: G E
authors.initials: GE
authors.lastname: Swan
mesh_terms: D000096:Acetone; D000504:Aloe / Q000737:chemistry*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D016995:Ehrlichia ruminantium / Q000187:drug effects*; D006357:Heartwater Disease / Q000188:drug therapy* / Q000517:prevention & control; D066298:In Vitro Techniques; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D031298:Mimosa / Q000737:chemistry*; D010118:Oxytetracycline / Q000494:pharmacology; D008517:Phytotherapy / Q000379:methods / Q000662:veterinary*; D010936:Plant Extracts / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D000096:Acetone; D010118:Oxytetracycline