Phela is a herbal traditional medicine product prepared using well defined parts of four
African medicinal plants. The aim of the study was to determine the mechanism of
action by which phela boosted the immune system of a rat model.
Unfortunately, subsequent literature research revealed that very little is known about
phela. As such chromatographic methods were developed by which to identify phela
and for quality control purposes. Of note, the developed methods complemented each
other; they were compiled into a comprehensive method for phela fingerprinting. It
involved sample extraction of the phela by either acidic extraction or a simple âsaltingoutâ
method, followed by Thin Layer Chromatography (TLC), and/or preparative Column
Chromatography (CC) that were supported by High Performance Liquid
Chromatography with UV-detector (HPLC_UV), HPLC with fluorescence detector
(HPLC_FL), HPLC with photo diode array detector (HPLC_PDA) and Gas
Chromatography-Mass selective detector (GC_MSD) spectrometry. The method was
successfully used to differentiate phela from another herbal product made from
Hypericum perforatum (St Johnâs wort) illustrating its high potential for application to
other herbal medicines in development.
Thereafter a HPLC_UV method for monitoring phela in plasma was developed and
validated. However, due to its pitfalls, a HPLC_FL method was developed as well. The
HPLC_UV method had a linear regression equation of y = 0.02x â 0.59, correlation
coefficient of r2 = 0.9983 and accuracy within 15 %. For HPLC_FL three marker peaks
were selected and standardized by the retention time. The developed HPLC_UV and
HPLC_FL methods were tested by analysing blood collected from rats treated with
phela after 1, 2, 4, 6 and 8 hours respectively. Unfortunately, analysis by HPLC_UV method had no peaks whereas, during HPLC_FL method analysis, a new peak was
observed at 9.2 minutes.
The peak was depicted as a metabolite for phela and was then utilized as the plasma
marker. Since the metabolite is unknown and therefore no standard exists by which to
express its plasma concentration in conventional units, the changes in peak area per
unit volume (L) of plasma (peak-area/L) were used to derive the appropriate
pharmacokinetic parameters hence peak-kinetics. The predictive parameters show that
concentration of the metabolite at steady state would be 48 peak-area/ml, hence no
accumulation of the drug.
The final part of the study was undertaken to understand the mechanism of action of
phela using a rat model by observing for changes in the levels of TH1 and TH2
cytokines. Rats were divided into six groups. The first group was not treated with
anything. The four groups were treated daily with either normal-saline, orally (control);
cyclosporine in olive oil, subcutaneously (negative control); Phela, orally (test-group 1)
and phela+cyclosporine (test-group 2). The last group was inoculated once with
influenza vaccine. The treatment period was 14 days and in each group rats were
sacrificed after 7 and 14 days. Haematology tests, biochemistry tests, and cyclosporine
level analysis were done. Serum cytokine analysis for TH1 (IL-2, IFN-γ and TNF-α) and
TH2 (IL-4 and IL-10) cytokines was measured by ELISA.
On days 7 and 14, the concentrations of TH1 cytokines in the Phela-only treated group
were similar to the control. However, the TH1 cytokines were higher in the
Phela+cyclosporine-A treated group than in the cyclosporine-A group, and cyclosporine-
A concentrations were similar in both groups. These results show that Phela did not
affect TH1 cytokines of a normal immune system but stimulated them when the immune
system was suppressed by cyclosporine-A. This implies that Phela is a cyclosporine-A
antagonist that may stimulate a compromised immune system. In conclusion, Phela is
an immune stimulant.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-12152010-114446 |
| Date | 15 December 2010 |
| Creators | Lekhooa, Makhotso Rose |
| Contributors | Dr MG Matsabisa, Dr JB du Plessis, Prof A Walubo |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-12152010-114446/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.338 seconds