Submitted in complete fulfilment for the Degree of Doctorate of Technology (Biotechnology)--Durban University of Technology, 2013. / South Africa has the largest number of people infected with HIV/AIDS. It also has more than
30 000 species of plants and many of these have a long tradition of medicinal use. It is highly
likely that the treatment for HIV will come from this traditional knowledge. The need for
effective preventative and therapeutic agents for HIV remains an urgent global priority. The
aim of this study was to screen selected South African medicinal plants for anti-HIV activity
and to identify and characterise an active compound from a plant that can be used for HIV
treatment. The aqueous and methanolic extracts of the roots, leaves, flowers and stems of
thirty eight plant species (108 extracts) were screened for anti-HIV activity. The plants which
had anti-HIV activity were further screened for anti-reverse transcriptase activity. Thirty-two
extracts exhibited varying degrees of anti-HIV activity. Cleome monophylla, Dichrostachys
cinerea and Leonotis leonurus aqueous leaf extracts had anti-HIV-1 reverse transcriptase
activity.
The aqueous extracts of D. cinerea showed the best anti-HIV activity with a Selectivity Index
of 43.5 and significant anti-HIV-1 reverse transcriptase activity. Crude phytochemical
screening of D. cinerea showed that it had tannins, saponins, flavonoids and alkaloids but did
not contain any phlobatannins, terpenoids, steroids or phenols. D. cinerea displayed a high
degree of free radical scavenging activity with an IC50 of 25 μg/ml, therefore the anti-HIV
activity could be attributed to the flavonoids present in the plant.
Bio-guided fractionation was used to isolate and purify the active compound from the D.
cinerea extract. Compounds were isolated by thin layer chromatography and were tested for
anti-HIV-1 and anti-reverse transcriptase activity. From these results the active compound
was identified, and purified using preparative TLC. The active compound was characterised
by High Performance Liquid Chromatography, Ultraviolet-visible spectrophotometry, and
Ultra Performance liquid chromatography coupled to MS/MS. Structural elucidation was
performed using Nuclear Magnetic Resonance. From these results, it was deduced that the
compound isolated from D. cinerea was a catechin.
In this study we show that the catechins present in D. cinerea are responsible for the anti-
HIV-I activity and inhibits the reverse transcriptase activity which is a key factor in the
progression of HIV. Potentially, these results can be used to develop a new drug for the
treatment of HIV or as a cost effective therapeutic agent in treating HIV-infected individuals
with oxidative stress. / National Research Foundation
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:dut/oai:localhost:10321/916 |
| Date | 17 September 2013 |
| Creators | Hurinanthan, Vashka |
| Contributors | Odhav, Bharti, Parboosing, Raveen |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 160 p |
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