Spelling suggestions: "subject:"dentífrica, southern."" "subject:"dentífrica, nouthern.""
1 |
A biosystematic study of the genus Sutherlandia Br. R. (Fabaceae, Galegeae)Moshe, Dineo 16 August 2012 (has links)
M.Sc. / A biosystematic study of the genus Sutherlandia (L.) R. Br., a poorly studied genus with confusing geographical variants, is presented. The species of Sutherlandia are all endemic to southern Africa. The species are very closely related and problems regarding their taxonomy are discussed. A few morphological characters that are useful in distinguishing amongst species are illustrated and discussed in detail. Morphological data are used to investigate infrageneric relationships in a phenetic analysis of 51 geographically separated populations. Sutherlandia has traditional medicinal uses, mainly as an anti-cancer treatment for internal cancers and as a general tonic. A survey of chemical compounds was done and the results are illustrated and presented in tables. The nature of this study did not allow detailed medical investigations, but the medicinal value of Sutherlandia and the compounds detected are highlighted. It is suggested that the anti-cancer activity can mainly be ascribed to the high levels of canavanine, a non-protein amino acid, in the leaves of the plant. Canavanine, an arginine analogue, is known for its antitumourigenic properties. The value of the plant as a bitter tonic is probably related to the presence of several triterpenoids, some of which may well also have other beneficial effects. Enzyme electrophoresis was done to explore genetic relationships amongst the numerous regional forms of Sutherlandia. A study of 19 populations showed that they are all closely related and that a more conservative treatment of the taxa is called for. As a result the number of taxa is reduced. A complete taxonomic revision of the genus is presented. The number of species is reduced from six to two, namely S. frutescens and S. tomentosa. The former is divided into three subspecies, namely subsp. frutescens, subsp. microphylla and subsp. speciosa. Some regional forms are described and illustrated, but these are not formally recognised as taxa. A key to the species, subspecies and regional forms is provided, and the. nomenclature, typification, description and geographical distribution for each of the taxa are given. The multidisciplinary approach of this study provided a better understanding of the morphological, chemical and genetic variation in this relatively poorly known but potentially valuable ornamental and medicinal plant.
|
2 |
Extractives of three southern African medicinal plants.Page, Bronwen Ann. January 1998 (has links)
In this investigation the chemistry of three southern African plants used for medicinal purposes was
investigated. The plants were Dioscorea dregeana, Avonia rhodesica and Equisetum ramossisimum.
Extracts of all three of these plants have been found to be active on the central nervous system. The
structures of the compounds isolated were determined by using 1H and 13C n.m.r., i.f., UV-VIS,
- mass spectroscopy and chemical methods.
D. dregeana yielded two alkaloids and three aromatic compounds. A. rhodesica contained a large
amount of wax which was analysed by GC-MS and its distribution and physical nature on the
surface of the leaves was determined by SEM (scanning electron microscopy). This plant also
contained two sterols. Equisetum ramossisimum extracts contained a carotenoid and several
porphyrins, as well as large amounts of silica. A DTSA X-ray microanalysis system (which was a
component of the scanning electron microscope) was used to determine the distribution of silica in
the stem. / Thesis (M.Sc.)-University of Natal, Durban, 1998.
|
3 |
Southern African plants used to treat central nervous system related disorders.Stafford, Gary Ivan. January 2009 (has links)
The majority of the population in South Africa use traditional health care to treat various mental conditions. This thesis has two main objectives; to bring together a comprehensive and detailed record of psychotropic plants used in southern Africa by indigenous peoples for medicinal or cultural purposes. Secondly, this research attempts to investigate the validity and rationale of the use of these plants by screening them in various biological assays for psychotropic activity. Plants were selected, based on their traditional use and availability, and were screened in four assays, which detect biological activity of a useful nature. A number of in vitro enzymatic and neuronal signal transduction assays were employed in this thesis, the inhibition of the serotonin reuptake transporter protein (SERT); inhibition of catabolic enzymes (e.g. acetylcholinesterase, monoamine oxidase); GABAA- benzodiazepine receptor binding. The influence of legislation, past and present, on the state of traditional medicine is highlighted. Aspects of the philosophies and practises of the various practitioners of South African traditional medicine will be discussed. An annotated list compiled from available ethnobotanical literature of plants traditionally used for central nervous system-related purposes is provided. It contains more than 330 species, from 94 families, which are currently used or have been used for cultural, medicinal and recreational purposes related to the central nervous system (CNS). Where available, information pertaining to plant part used, preparation method, dosage, route of administration, known and potentially active constituents are included. Seventy five extracts from 34 indigenous plant species used in South African traditional medicine or taxonomically related to these were investigated for their affinity to the serotonin reuptake transport protein, making use of an in vitro [3H]-citalopram serotonin reuptake transport protein binding assay. Aqueous and 70% ethanolic extracts of various plant parts were screened and 45 extracts derived from 15 plant species showed affinity. The affinity of 12 extracts from four plants was characterized as high (more than 50% inhibition at 5, 1, and 0.5 mg/ml). Plant species with high affinity to the serotonin reuptake transport protein included Agapanthus campanulatus, Boophone disticha, Datura ferox and Xysmalobium undulatum. Agapanthus campanulatus yielded high activity in aqueous extracts from leaves and flowers. B. disticha showed high activity both in aqueous and ethanolic extracts of leaves and bulbs. D. ferox showed high activity in aqueous extracts from the seeds and X. undulatum showed high activity in the ethanolic extract of the whole plant. Two compounds, buphanadrine and buphanamine, were isolated by bioassay-guided fractionation on vacuum-liquid-chromatography (VLC) and preparative thin-layer-chromatography (TLC) from B. disticha. The structures of the compounds were determined by 1H and 13C NMR. Fractions were tested for affinity to the serotonin transporter in a binding assay using [3H]-citalopram as a ligand. The IC50 values of buphanidrine and buphanamine were 274 ìM (Ki = 132 ìM) and 1799 ìM (Ki = 868 ìM), respectively. The two alkaloids were also tested for affinity to the 5HT1A receptor, but only showed slight affinity. Aqueous and ethanol extracts of 43 plants that are traditionally used to treat against epilepsy and convulsions were initially tested in the GABAA-benzodiazepine receptor binding assay, where the binding of 3H-Ro 15-1788 (flumazenil) to the benzodiazepine site is measured. The GABAA-benzodiazepine receptor complex is involved in epilepsy and convulsions. Out of the 118 extracts tested, one aqueous and 18 ethanol extracts showed activity. The most active extracts were the ethanolic leaf extracts of Searsia tridentata, Searsia rehmanniana and Hoslundia opposita and the ethanolic corm extract of Hypoxis colchicifolia, which all showed good dose-dependent activity. A further forty-six ethanol extracts from another 35 species, both indigenous and exotic that are traditionally used predominantly as sedatives or to treat various CNS-related ailments were tested in the GABAA-benzodiazepine receptor-binding assay. Out of the 46 extracts tested, seven showed good activity and 10 showed moderate activity. The most active extracts were the ethanolic leaf extracts of Arctopus echinatus, Artemisa afra, four Helichrysum species and Mentha aquatica which all showed good dose-dependent activity. Two biflavonoids with activity in the 3H-Ro 15-1788 (flumazenil) binding assay were isolated by high pressure liquid chromatography (HPLC) fractionation of the ethanol extract of the leaves from Searsia pyroides. The structures of the two biflavonoids were elucidated by nuclear magnetic resonance spectroscopy (NMR) to be agathisflavone and amentoflavone. Agathisflavone and amentoflavone competitively inhibited the binding of 3H-Ro 15-1788 with a Ki of 28 and 37 nM, respectively. Extracts of Searsia dentata and Searsia pentheri were not as active as the extract from Searsia pyroides; both were found to contain apigenin and agathisflavone. The monomer apigenin, agathisflavone and amentoflavone were fitted into a pharmacophore model for ligands binding to the GABAA receptor benzodiazepine site. This reflected the affinities of the compounds in the [3H]-flumazenil binding assay. Mentha aquatica, a mint that is found in Europe and Africa, is used in Zulu traditional medicine for spiritual purposes. The ethanolic leaf extract showed a strong affinity to the GABA-benzodiazepine receptor. Viridiflorol from the essential oil and (S)-naringenin from an ethanolic extract was isolated by bioassay-guided fractionation using binding to the GABA-benzodiazepine site. Viridiflorol had an IC50 of 0.19 M and (S)-naringenin of 0.0026 M. Twenty plants used in Zulu traditional medicine for several CNS-related ailments were screened for MAO inhibition and specific MAO-B inhibition activity. MAO-B inhibitors are currently employed in the treatment of neurodegenerative related illnesses such as Parkinson's and Alzheimer's diseases. A photometric peroxidase linked assay was used to determine the inhibition of the oxidative deamination of tyramine by MAO isolated from rat liver. Ruta graveolens exhibited the best MAO inhibitory activity (ethyl acetate leaf extract = IC50 5 ± 1 ìg/ml, petroleum ether extract = 3 ± 1 ìg/ml) and specific MAO-B inhibition (ethyl acetate leaf extract = IC50 7 ± 6 ìg/ml petroleum ether extract = 3 ± 1 ìg/ml). Schotia brachypetala, Mentha aquatica and Gasteria croucheri also exhibited good MAO-B inhibition activity. Six extracts of varying polarity of Mentha aquatica were tested in a photometric peroxidase linked MAO bioassay. The 70% ethanol extract had highest inhibitory activity. (S)-Naringenin was isolated from the extract by bioassay guided fractionation on VLC and preparative TLC. The structure of the compound was determined by 1H, 13C and 13C-DEPT NMR and optical rotation. The IC50 values for MAO inhibition by naringenin were 342 ± 33 ìM for the rat liver mitochondrial fraction, 955 ± 129 ìM for MAO-A and 288 ± 18 ìM for MAO-B respectively. South African traditional medicine clearly utilizes many botanical species with CNS-related activity. Only a small number of the more than 330 southern African plant species reported to treat or alter the CNS have been scientifically evaluated. To date very few of the active compounds have been isolated and identified. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
|
4 |
Character variation and a cladistic analysis of the genus Lachenalia Jacq.f. ex Murray (Hyacinthaceae:Massonieae)Duncan, Graham D. January 2005 (has links)
Morphological variation and a cladistic analysis of the large, endemic Southern African genus
Lachenalia Jacq.f. ex Murray (Hyacinthaceae: Massonieae) is presented. Its close taxonomic
relationship with the small endemic sympatric genus Polyxena Kunth (which has been included in the morphological and cladistic study) is discussed. The inclusion of Polyxena
within Lachenalia is supported. One hundred and twenty species (139 taxa), comprising 115
Lachenalia and five Polyxena species are recognised. A wide range of morphological characters were analysed, including macromorphology,
micromorphology, anatomy and palynology. A discussion and comparison of karyological data is also presented.
A brief historical background, species diversity maps, figures, tables, appendices and illustrations of anatomical, micromorphological and macromorphological characters, and
cladistic data, are presented, as well as discussions of pollination biology and phytogeography.
This work is based on species studied in their natural habitats as well as under cultivation,
and from representative herbarium specimens examined from BOL, NBG, PRE and SAM. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
|
5 |
Climate and woody plant species richness : analyses based upon southern Africa's native flora with extrapolations to subsaharan AfricaO'Brien, Eileen M. January 1990 (has links)
No description available.
|
6 |
Isolation of bioactive metabolites with activity against HIV-1 target proteins from extracts of Sutherlandia frutescens and Lobostemon trigonusDambuza, Ntokozo Shirley January 2007 (has links)
Acquired Immunodeficiency Syndrome (AIDS) is a human disease caused by the human immunodeficiency virus type 1 (HIV-1) and it is one of the biggest social, economic and health challenges in the world. The Joint United Nations Programme on HIV/AIDS (UNAIDS) and World Health Organization (WHO) estimated that between 33.4 to 46.0 million people around the world were living with HIV/AIDS in December 2005 and the highest estimates are in the Sub-Saharan Africa (around 25 million). In more developed countries a combined antiretroviral therapy called highly active antiretroviral therapy (HAART) is used, which results in reduced progression to AIDS in most patients. Despite the beneficial effects of HAART, significant side effects are experienced by treated patients. In addition, most infected people live in countries where the treatment is very expensive or, in many cases, not available at all. These people therefore rely on medicinal plants for health care. In this study, aqueous extracts from Sutherlandia frutescens and Lobostemon trigonus were screened for potential anti-HIV activities in a series of in vitro enzymatic assays, including reverse transcriptase, HIV-1 protease and glycohydrolases. Two extracts of Sutherlandia leaves (SFL-1 and SFL-2) were prepared that inhibited HIV reverse transcriptase and a Lobostemon leaf extract (LTL) was shown to also inhibit this enzyme. All extracts were assayed at 1.25mg/ml. Tannin content was determined for all active extracts using a tannic acid assay. SFL-1 and SFL-2 were found to contain about 6 percent and 7 percent tannins, respectively, and LTL contained 31% tannins by weight. Tannins were removed using polyamide columns and three fractions were collected for each. The extracts were also fractionated with Sephadex G-25, Amberlite IR 120 and Dowex 1-X8 as size exclusion, cation exchange and anion exchange, respectively. Extracts were also fractionated by preparative thin layer chromatography where two compounds were separated from S. frutescens extract with high activity against reverse transcriptase while showing insignificant inhibition towards other enzymes tested. SFL-BFW-10 and SFL-WEF-7 inhibited reverse transcriptase by almost 100 percent and the IC50 values calculated for these compounds were 0.34 and 0.23mg/ml, respectively. Cytotoxicity of these compounds was evaluated on Chang liver cells and peripheral blood mononuclear cells (PBMCs). None of these compounds showed any significant inhibition of cell proliferation. The purity of these compounds could not be confirmed because there was insufficient material to use in the techniques required to show purity and identification. Therefore, TLC was used to determine the nature of these compounds. SFL-BFW-10 was identified as an organic acid and SFL-WEF-7 was identified as flavonoid.
|
7 |
Systematic significance of bulb morphology of the Southern African members of Oxalis L. (Oxalidaceae)Gebregziabher, Awot Kiflu 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: The systematics of the southern African members of the genus Oxalis L. (Oxalidaceae) is in a
state of flux. The bulbs of these species contain potential taxonomically important characters
and therefore require detailed study (Salter, 1944). A pilot study assessed the homology of
bulbs among southern African Oxalis species (Gebregziabher, 2001), and found that they are
all homologous structures. This pilot study also emphasized the range of potentially
informative characters from different bulb parts.
The aim of the present study was to assess the taxonomic significance of bulb morphology in
selected southern African Oxalis species. As far as possible, efforts were made to represent
both the taxonomic (Salter, 1944) and palynological diversity (Dreyer, 1996) present in the
genus.
Detailed bulb morphological studies of 30 species of southern African Oxalis species revealed
41 potentially informative characters. Different bulb-types were identified based on these
characters. Bulb-type affinities of taxa included in this study, as well as bulb descriptions
from the pilot study (Gebregziabher, 2001), were discussed. Comparison with the current
taxonomic classification (Salter, 1944), palynological classification (Dreyer, 1996) and a
preliminary phylogeny based on the non-coding plastid trnL-trnF DNA region (Oberlander,
2003), were also made. Bulb morphology conflicted with the current taxonomic classification
(Salter, 1944), but showed greater congruence with both the palynological groupings and the
trnL-trnF based phylogeny.
Based on this study, bulb morphology is found to be taxonomically significant. Further
studies on the bulb morphology and anatomy of southern African Oxalis species are merited.
Key words: bulb morphology, Oxalis, informative characters, basal plates, fleshy leaves,
tunics / AFRIKAANSE OPSOMMING: Die sistematiek van die suider Afrikaanse lede van Oxalis L. (Oxalidaceae) is labiel. Die bolle
van hierdie spesies sluit potensieel taksonomies belangrike kenmerke in, en behoort daarom in
detail bestudeer te word (Salter, 1944). In Loodsstudie het die homologie van die bolle van die
suider Afrikaanse Oxalis spesies ge-evalueer (Gebregziabher, 2001), en gevind dat hulle
homoloë strukture is. Resultate van hierdie loodsstudie het ook die reeks van potensieel
informatiewe kenmerke van verskillende boldele beklemtoon.
Die doel van hierdie studie was om die taksonomiese belang van boImorfologie in
geselekteerde suider Afrikaanse Oxalis spesies te ondersoek. Pogings is aangewend om, sover
moontlik, beide die taksonomiese (Salter, 1944) en die palinologiese (Dreyer, 1996)
diversiteit van die genus in die studie in te sluit.
Gedetailleerde bol-morfologiese studies van 30 suider Afrikaanse Oxalis spesies het 41
potensieel informatiewe kenmerke uitgewys. Gebaseer op hierdie kenmerke, is verskillende
bol-tipes geïdentifiseer. Verwantskappe tussen die bol-tipes van die spesies ingesluit in
hierdie studie, sowel as beskrywings van bolle volgens die loodsstudie (Gebregziabher, 2001),
word bespreek. Vergelykings met die huidige taksonomiese klassifikasie (Salter, 1944),
palinologiese klassifikasie (Dreyer, 1996) en In voorlopige filogenie gebaseer op die niekoderende
plastied trnL-F DNA-streek (Oberlander, 2003) is ook getref. BoImorfologie
weerspreek die huidige taksonomiese klassifikasie (Salter, 1944), maar toon groter
ooreenstemming met beide die palinologiese groeperings en die trnL-F gebaseerde filogenie.
Hierdie studie het bevind dat bolmorfologie van taksonomiese waarde is. Verdere studies op
die bolmorfologie en -anatomie van die suider Afrikaanse Oxalis spesies word aanbeveel.
|
8 |
Bioprospecting the flora of southern Africa : optimising plant selections.Douwes, Errol. January 2005 (has links)
Focused procedures which streamline and optimise plant prioritisation and selection in
bioprospecting have the potential to save both time and resources. A variety of semiquantitative
techniques were assessed for their ability to prioritise ethnomedicinal taxa in
the Flora of Southern Africa (FSA) region. These techniques were subsequently
expanded upon for application in plant selection for the Novel Drug Development
Platform bioprospecting programme.
Least squares regression analyses were used to test the hypothesis that ethnomedicinal
plant use in southern Africa is strictly random, i.e. no order or family contains
significantly more medicinal plants, than any other order or family. This hypothesis was
falsified revealing several 'hot' plant orders. The distribution of southern African
ethnomedicinal taxa was investigated, and revealed low ethnomedicinal plant usage in
the Western Cape and Northern Cape. The historical settlement of Bantu tribes in the
eastern regions of southern Africa was one explanation for this discrepancy. Growth
forms of ethnomedicinal taxa in 'hot' orders (identified in the regression analysis) were
analysed. The results indicated no clear preferences across orders, but rather a
preference for particular growth forms in certain orders. With respect to distribution,
endemism and Red Data List status of ethnomedicinal taxa, the Western Cape had the
greatest proportion of endemics and Namibia had the highest proportion of Red Data
Listed ethnomedicinal taxa. With respect to chemotaxonomy, the Asteraceae contained
the highest proportion of terpenoids, the Rubiaceae the highest proportion of alkaloids
and the Fabaceae the highest proportion of flavonoids.
The predictive value of regression analyses was tested against an existing analysis of
anti-malarials and the subsequent in vitro bioassays on Plasmodium falciparum. In
particular, the ability of these analyses to identify plants with anti plasmodial IC50 values
of [less than or equal to] 10 [micro]g/ml was assessed. Most species in 'hot' genera showed comparatively good
antiplasmodial activities (IC50 [less than or equal to] 10 [micro]g/ml).
Plant candidates were prioritised for screening anti-tuberculosis, anti-diabetes and
immune-modulatory compounds, using a weighting system based on;
their ethnomedicinal application, chemotaxonomic potential, frequency in ethnomedicinal
trade, association with the relative disease, toxicity, Red Data status, indigenous or
endemic status, and family selection in ethnomedicine (identified through regression
analyses). Other taxa were short-listed due to their presence in biodiversity hotspots
where few ethnomedicinal plant use records are documented, and still others were
incorporated due to their taxonomic association with efficacious exotic allies. Statistical
analyses of the weighting processes employed were not possible in the absence of
screening results which are due only in December 2006.
The legislation governing bioprospecting in South Africa is discussed and several
recommendations are presented to minimise negative impacts on the industry. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
|
9 |
Antimicrobial activity of Melianthus villosusLentsoane, Robert 23 May 2005 (has links)
Many South Africans continue to use traditional medicine in their daily lives as an alternative form of health care, also as part of their cultural heritage. Medicinal plants are proving to be an important source of novel drugs, and the knowledge provided by traditional healers is a useful tool in the search for antimicrobials. The antimicrobial activity of <M. villosus was investigated against ten bacteria and six fungi. The antibacterial assay showed that the root extract had the highest inhibition against the Gram-positive bacteria at the minimum inhibition concentration of o.1 mg/ml, as well as against the Gram-negative, E. coli, at the MIC of 1.0 mg/ml. Antifungal activity was witnessed against Cladosporium cladosporoide, C. cucumerinum&C sphaerosperum all at the minimum inhibitory concentration of 1.0 mg/ml. An attempt was made to isolate and identify the active antimicrobial compounds. A flavonol, quercetin was isolated and identified by means of UV spectral graphs, and TLC comparison of the plant extract and standard. However, a second isolated antibacterial compound could not be identified fully but it can be said that it is a triterpenoid. / Dissertation (MSc (Botany))--University of Pretoria, 2006. / Plant Science / unrestricted
|
10 |
Indigenous knowledges: a genealogy of representations and applications in developing contexts of environmental education and development in southern AfricaShava, Soul January 2009 (has links)
This study was developed around concerns about how indigenous knowledges have been represented and applied in environment and development education. The first phase of the study is a genealogical analysis after Michel Foucault. This probes representations and applications of plant-based indigenous knowledge in selected anthropological, botanical and environmental education texts in southern Africa. The emerging insights were deepened using a Social (Critical) Realism vantage point after Margaret Archer to shed light on agential issues in environmental education and development contexts. Here her morphogenetic/morphostatic analysis of social transformation or reproduction is used to trace changes in indigenous knowledge representations and applications over time (from the pre-colonial into the post-colonial era). The second phase uses the same perspectives and tools to extend the analysis of power/knowledge relationships into the interface of indigenous communities and modern institutions in two case study settings in the Eastern Cape of South Africa. This study reveals colonially-derived hegemonic processes of modern/Western scientific institutional representations/interpretations of the knowledges of indigenous communities. It also tracks a continuing trajectory of their dominating and prescriptive mediating control over local knowledges from the pre-colonial context through into the post-colonial period in southern Africa. The analysis reveals how this hegemony is sustained through the deployment of institutional strategies of representation that transform local knowledges into the disciplinary knowledge discourses of modern scientific institutions. These representational strategies therefore generate/reproduce and validate disciplinary discourses about the other, constructing disciplinary 'regimes of truth'. In this way modern institutions appropriate and displace indigenous/local knowledges, silence the voices of local communities and regulate individual and community agency within a continuing subjugation of indigenous knowledges. This study reveals how working within modern institutions and disciplinary knowledges in participative education and development interactions can serve to implicate indigenous researchers in these institutional hegemonic processes. The study also notes evidence of a continued resistance to hegemonic Western knowledge discourses as indigenous communities have sustained many knowledge practices alongside Western knowledge discourses. There is also evidence of a recent emergence of counter-hegemonic indigenous knowledge discourses in environmental education and development practices in southern Africa. It is noted that these have been contingent upon the changing political terrain in southern Africa as this has opened the way for alternative discourses to the dominant conventional Western knowledges in formal education and development contexts. The counterhegemonic discourses invert power/knowledge relations, decentre hegemonic discourses and reposition indigenous knowledges in formal education and development contexts. This study suggests the need to foreground indigenous knowledges as a process of knowledge decolonisation that gives contextual and epistemic relevance to environmental education and development processes. This calls for a need for new strategies to transform existing institutions by creating enabling spaces for the representational inclusion of indigenous knowledges in formal/conventional knowledge discourses and their application in social contexts. This opens up possibilities for plural knowledge representations and for their integrative and reciprocal co-engagement in situated contexts of environmental education and development in southern Africa.
|
Page generated in 0.0831 seconds