EVALUATION OF THE ACTIVITY OF LEAF EXTRACTS OF TREES THAT HAVE BEEN USED TO TREAT DIARRHOEA IN HUMANS AND ANIMALS

Abstract

The use of medicinal plants has been increasing exponentially over the last few years. The rural population of developing countries has always depended greatly on traditional herbal medicine, but also in the first world countries, alternative healing methods have been gaining more and more importance, especially in Europe after the restriction of antibiotic food additives for stock animals by the European Union. In this study 53 tree species were evaluated for their antibacterial activity and their tannin content in order to study the mechanisms of their uses as remedies against diarrhoea in humans and animals. The antibacterial activity was tested against one Gram-positive (Staphylococcus aureus) and one Gram-negative (Escherichia coli) bacterial strain using the microdilution assay. The assays were done in triplicate and were repeated three times. Furthermore bioautographic assays were done. The compounds were visualised using Thin Layer Chromatography. For the evaluation of the tannin content, the radial diffusion assay was used. Five selected tree species were collected and tested every month for their antibacterial activities and tannin content in the same manner in order to show possible seasonal variations.Those five plants were Acacia karoo, Acacia sieberiana, Peltophorum africanum, Trichilia emetica and Ziziphus mucronata. Samples of various different trees of the species Combretum molle were collected at different locations and analyzed in the same manner to show possible interspecies variation and possible variation due to the localization of the plant. The results of this study will help to understand which mechanism each plant employs to be used as an effective remedy against diarrhoea.