Abstract
Few in vitro screening assays for biological activities of plant extracts consider the potential effect of the gastrointestinal system on orally
consumed plant extracts. Crude water and methanol extracts of Tarchonanthus camphoratus (wild camphor) and Agathosma betulina (‘buchu’)
were prepared and exposed to simulated gastric fluid and simulated intestinal fluid during dissolution studies to address this aspect. The crude
extracts and resulting simulated gastric fluid and simulated intestinal fluid products were screened for antimicrobial activity against Staphylococcus
aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922) and Proteus vulgaris (ATCC 33420). The
T. camphoratus crude extract exhibited antimicrobial activity which was reduced after exposure to simulated gastric fluid. After exposure to
simulated intestinal fluid no antimicrobial activity was detected, which suggests chemical alteration or degradation of the active compounds. For
A. betulina, the crude water extract and simulated gastric fluid product exhibited no antimicrobial activity, while the simulated intestinal fluid
product exhibited antimicrobial activity. This suggests activation of antimicrobial constituents during exposure to simulated intestinal fluid. The
chemical composition profiles of the crude extracts and products were determined by means of liquid chromatography coupled to an ultraviolet
detector (LC-UV) and a mass spectrometer (LC-MS) to qualitatively assess the effect of exposure to simulated gastrointestinal conditions on the
chemical composition of the extracts. In many cases, the peak area of compounds decreased after exposure to simulated gastric fluid and simulated
intestinal fluid, while the peak area of other compounds increased. Thus, it can be deduced that the antimicrobial activity and chemical
composition was altered after exposure to intestinal conditions during dissolution studies.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:tut/oai:encore.tut.ac.za:d1001732 |
| Date | 07 1900 |
| Creators | Vermaak, I, Viljoen, AM, Hamman, JH, Van Vuuren, SF |
| Publisher | Elsevier |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | |
| Rights | © 2009 SAAB |
| Relation | South African Journal of Botany |
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