A bstract
Few in vitro screening studies on the biological activities of plant extracts that are intended for oral
administration consider the effect of the gastrointestinal system. This study investigated this aspect on
extracts of Camellia sinensis (green tea) and Salvia officinalis (sage) using antimicrobial activity as amodel
for demonstration. Both the crude extracts and their products after exposure to simulated gastric fluid
(SGF) as well as simulated intestinal fluid (SIF) were screened for antimicrobial activity. The
chromatographic profiles of the crude plant extracts and their SGF as well as SIF products were recorded
and compared qualitatively by means of high performance liquid chromatography coupled to mass
spectrometry. The effect of epithelial transport on the crude plant extracts was determined by applying
them to an in vitro intestinal epithelial model (Caco-2). The crude extracts for both plants exhibited
reduced antimicrobial activity after exposure to SGF, while no antimicrobial activity was detected after
exposure to SIF. These results suggested chemical modification or degradation of the antimicrobial
compounds when exposed to gastrointestinal conditions. This was confirmed by a reduction of the peak
areas on the LC–UV–MS chromatograms. From the chromatographic profiles obtained during the
transport study, it is evident that some compounds in the crude plant extracts were either not
transported across the cell monolayer or they were metabolised during passage through the cells. It can
be deduced that the gastrointestinal environment and epithelial transport process can dramatically
affect the chromatographic profiles and biological activity of orally ingested natural products.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:tut/oai:encore.tut.ac.za:d1001730 |
| Date | 20 April 2009 |
| 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 | c 2009 Phytochemical Society of Europe |
| Relation | South African Journal of Botany |
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