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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
351

Pharmacological investigation of some trees used in South African traditional medicine.

Eldeen, Ibrahim Mohamed Suliman. January 2005 (has links)
South Africa is home to a wide diversity of cultural groups, all of which utilize the flora for a variety of purposes. This is true with regard to traditional medicine systems which are similar to those of the rest of Africa south of the Sahara, with diviners (sangomas) and herbalists (inyangas) as the key health providers. In addition, the Country is rich in plant diversity with some 30 000 species of flowering plants - almost one tenth of the worlds recorded higher plants. This incorporates a large diversity of plants including trees, shrubs, herbs, bulbs and corms. The adverse effects of traditional medicinal plants and natural products are not well documented in the literature. Recently, many plants used as food or in traditional medicine have been shown to be potentially mutagenic using in vitro assays. Thus, the scientific evaluation of traditional medicine and medicinal plants is very important to validate claims made on safety and efficiency of such usages. After a survey of the available ethnobotanical literature, ten trees used in South African traditional medicine were selected. These species were: Acacia niolotica subspecies kraussiana, Acacia sieberiana, Albizia adianthifolia, Combretum kraussii, Faidherbia albida, Ficus sur, Prunus africana, Salix mucronata, Terminalia sericea and Trichilia dregeana. Plant parts including leaf, root and bark were collected from each of the selected trees (exceptions were Albizia adianthifolia, Faidherbia albida, Terminalia sericea and Prunus africana) and extracted using ethyl acetate, ethanol and water individually to ensure the extraction of compounds over a wide range of polarities. The extracts (in total, 78) were screened for antibacterial, anti-inflammatory (COX-1 and COX-2) and antiacetylcholinesterase activities and investigated for their potential mutagenic effects using the Ames test. Antibacterial activity was detected using the disc-diffusion and microdilution assays. The extracts were tested against Gram-positive bacteria: Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus and Gram-negative bacteria: Escherichia coli and Klebsiella pneumoniae. Of the 78 different plant extracts 111 tested (final amount of plant material was 1 mg per disc), 84% showed activity against Gram-positive bacteria. From this percentage, 20% also showed activity against Gram-negative bacteria. The best inhibition was observed with ethyl acetate and ethanol root extracts of Terminalia sericea against both Gram-positive and Gram-negative bacteria. In the micro-dilution assay, 55% of the plant extracts showed minimum inhibitory concentration (MIC) values ~ 1.56 mg/ml against Gram-positive and/or Gram-negative bacteria. The ethyl acetate bark extract of Acacia sieberiana and the root and bark ethyl acetate extracts of Acacia nilotica inhibited bacterial growth of both Gram-positive and Gram-negative bacteria at concentrations ~ 0.8 mg/ml. The aqueous leaf extracts of Acacia sieberiana had a low MIC value (0.3 mg/ml) against Gram-negative Kleibsiella pneumoniae and the ethyl acetate extracts of the root inhibited growth of Escherichia coli with an MIC value of 0.1 mg/ml. However, these two extracts showed no activity in the disc-diffusion assay. The MIC values of the neomycin (control) were 0.8 I-Ig/ml and 3.1 I-Ig/ml against Kleibsiella pneumoniae and Escherichia coli respectively. In the anti-inflammatory test, 70% of the plant extracts from different plant parts (leaf, root, bark) of the tree investigated showed strong inhibition in both the CQX-1 and CQX-2 bioassays. The CQX-2 inhibitory effects of aqueous extracts were generally lower when compared to the organic solvent extracts. However, water extracts of Acacia nilotica was an exception (~ 90%). In the acetylcholinesterase inhibitory test, 21% of the plant extracts were active at concentrations ~ 1 mg/ml using the micro-plate assay. The lowest IC50 value was 0.04 mg/ml obtained with an ethanol bark extract of Combretum kraussii. The IC50 value of the galanthamine (positive control) was 2 I-IM. None of the investigated plants showed any potential mutagenic effects with Salmonella typhymurium strain TA 98 using the Ames test. Using bioassay-guided fractionation, anolignan B was isolated from the ethyl acetate root extract of Terminalia sericea. Antibacterial activity of anolignan B was determined using the microdilution assay. The compound possessed activity against both Gram-positive and Gram-negative bacteria. The lowest MIC value (3.8 IJg/ml) was observed with Staphylococcus aureus. MIC value of the neomycin was 1.5 IJg/ml. Anti-inflammatory activity of anolignan B was detected using the CQX-1 and CQX-2 bioasays. The compound showed strong inhibitory activity against CQX-1 and weaker activity against CQX-2. The ICso values were 1.5 mM and 7.5 mM with CQX-1 and CQX-2 respectively. The ICso values of indomethacin were 0.003 mM and 0.186 mM against CQX-1 and CQX-2 respectively. There were no potential mutagenic effects showen by anolignan B against Salmonella typhimurium strain TA 98 in the Ames test. Isolation of anolignan B from Terminalia species and the antibacterial and anti-inflammatory activities observed in this work have not been reported previously and could therefore be recorded as novel biological activities for this compound. These results also support the idea that the use of ethnobotanical data can provide a valuable short cut by indicating plants with specific uses which might likely be sources of biologically active chemicals. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
352

Micropropagation and medicinal properties of Barleria greenii and Huernia hystrix.

January 2009 (has links)
The crisis of newly emerging diseases and the resistance of many pathogens to currently used drugs, coupled with the adverse side-effects of many of these drugs have necessitated the continuous search for new drugs that are potent and efficacious with minimal or no adverse side-effects. The plant kingdom is known to contain many novel biologically active compounds, many of which could potentially have a higher medicinal value when compared to some of the current medications. Indeed, the use of plants in traditional medicine, especially in African communities, is gaining more importance due to their affordability and accessibility as well as their effectiveness. Exponential population growth rates in many developing countries has resulted in heavy exploitation of our plant resources for their medicinal values. In addition, plant habitat destruction arising from human developmental activities has contributed to the fragmentation or loss of many plant populations. Owing to these factors, many plant species with horticultural and/or medicinal potential have become either extinct or are threatened with extinction. These threatened species cut across different taxonomic categories including shrubs, trees and succulents. Without the application of effective conservation strategies, the medicinal and/or horticultural potential of such threatened species may be totally lost with time. The extinction of such species could lead to the loss of potential therapeutic compounds and/or genes capable of being exploited in the biosynthesis of new potent pharmaceutical compounds. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
353

Biological activity of traditional medicinal plants used against venereal diseases in South Africa.

Buwa, Lisa Valencia. January 2006 (has links)
Throughout the history of mankind, many infectious diseases have been treated with plant extracts. Venereal infections are one such group and are regarded as conditions that are highly responsive to traditional treatment. Aqueous, ethanol and ethyl acetate extracts of 13 plants used in South Africa for the treatment of venereal diseases were screened for in vitro antibacterial, antifungal, mutagenic and antimutagenic activities. Antibacterial activity was evaluated using the disc-diffusion and microdilution assays to determine the minimal inhibitory concentration (MIC) values of the extracts. The extracts were tested against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus, and the Gram-negative bacteria Escherichia coli and Klebsiella pneumoniae. Among the plants tested, Gunnera perpensa, Harpephyllum caffrum, Hypoxis latifolia and Ledebouria ovatifolia showed the best antibacterial activity. The aqueous rhizome extract of Gunnera perpensa displayed good activity against Gram-negative bacteria with an MIC value of 0.78 mg/ml, and against S. aureus (0.78 mg/ml). Aqueous and ethanol extracts of H. caffrum bark were active against both Gram-positive and Gram-negative bacteria. Hypoxis latifolia aqueous corm extracts exhibited very good MIC values against K. pneumoniae (0.78 mg/ml), E. coli and S. aureus (1.56 mg/ml). Ethanol and ethyl acetate bulb extracts of Ledebouria ovatifolia displayed good activity against Bacillus subtilis bacteria with MIC values of 0.78 mg/ml and 0.39 mg/ml respectively. Antifungal activity was evaluated using the microdilution bioassay. Good activity was shown by the ethanolic bark extracts of Bersama lucens and Harpephyllum caffrum against Candida albicans. Only in the case of Harpephyllum caffrum did aqueous extracts have activity against Candida albicans. In the Ames test, all plant extracts showed a negative genotoxic response except for ethanol and ethyl acetate bulb extracts of Cyrtanthus obliquus which induced mutations in TA98. Moderate antimutagenic activity was observed with the ethyl acetate extract of G. perpensa and the ethanolic extract of H. latifolia. High antibacterial and antifungal activity detected with Harpephyllum caffrum bark extracts resulted in an investigation on seasonal and geographical variation of this inhibitory activity. Seasonal variation in antibacterial and antifungal activities was investigated in order to determine the best collection time to ensure potential high medicinal activity in plant preparations. The highest inhibitory activity was detected with plant material collected in June and December 2003, with a decline in activity when collections were made in September 2004. The chemical profiles of TLC chromatograms were compared and little variation was found, particularly in the case of plant material obtained from the Botanic Garden of the University of KwaZulu-Natal and a 'Muthi' Shop in Pietermaritzburg. Identification of active compounds from G. perpensa and H. caffrum was not successful due to insufficient amounts of isolated fractions. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2006.
354

A pharmacological study of some Nigerian medicinal plants.

Chukwujekwu, Jude Chinedu. 10 December 2013 (has links)
Petroleum ether, dichloromethane, and 80% ethanol extracts of 15 plant species collected in Nigeria were screened for in vitro antibacterial, anti-inflammatory and antimalarial activities. Antibacterial activity was tested using the agar diffusion method, while the minimum inhibitory concentrations (MIC) of the active extracts were determined using the microtitre serial dilution method. Most antibacterial activity detected was against Gram-positive bacteria with Staphylococcus aureus being the most susceptible. The highest activity was found in petroleum ether and dichloromethane leaf extracts of Mallotus oppositifolius; petroleum ether, dichloromethane and ethanolic root extracts of Newbouldia laevis; and ethanolic root extracts of Morinda lucida and Canthium subcordatum. Against the Gram-negative bacterium Escherichia coli, the highest activity was found in dichloromethane leaf extracts of Newbouldia laevis, ethanolic root extracts of Phyllanthus amarus, Mallotus oppositifolius, and Canthium subcordatum. A total of 60 plant extracts were screened for antiplasmodial activity. A chloroquine sensitive strain of Plasmodium falciparum (D10) was used. In the assay, the parasite lactate dehydrogenase (pLDH) activity was used to measure parasite viability. About 11 extracts showed promising activity with an IC₅₀ ranging from 2.5 to 13.4 µg/ml. The petroleum ether leaf extract of Hyptis suaveolens had the highest activity (IC₅₀ = 2.5 µg/ml). The cyclooxygenase (COX-1 and COX-2) assays were used to test for anti-inflammatory activity. All the plant species, with the exception of Hedranthera barteri and Picralima nitida showed anti-inflammatory activity. Apart for a few ethanolic extracts, all the activities were recorded with petroleum ether and dichloromethane extracts. Employing bioassay-guided activity fractionation, an antibacterial anthraquinone identified as emodin was isolated from ethanolic root extract of Senna occidentalis. Although this compound had been isolated from other sources, this was the first report of isolation from Senna occidentalis. Using a similar approach a novel antimalarial diterpenoid was isolated from the petroleum ether leaves extract of Hyptis suaveolens. It had IC₅₀ of 0.1 µg/ml. This new compound is worthy of further investigation and may act as an important lead compound for future antimalarial drugs. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2005.
355

Pharmacology and phytochemistry of South African traditional medicinal plants used as antimicrobials.

Fawole, Olaniyi Amos. January 2009 (has links)
Among all the major infectious human diseases, gastro-intestinal infections caused by microbial pathogens are a major cause of morbidity and infant death in developing countries, largely due to inadequate sewage disposal and contaminated water. Traditional health practitioners in South Africa play a crucial role in providing health care to the majority of the population. Many plants are locally used by South African traditional healers to treat microbial infections related to gastro-intestinal tracts. Ethnopharmacological and ethnobotanical studies using traditional knowledge as a selection strategy has given priority to certain plants for isolation and identification of plant novel bioactive compounds. Pharmacological and phytochemical studies of the investigated twelve medicinal plant species (from 10 families) extensively used as antimicrobials against gastro-intestinal infections was necessary to validate the use of the plants. Furthermore, to provide sufficient preliminary information for the isolation and identification of active compounds that are present in the investigated plants. Plant parts were sequentially extracted using petroleum ether (PE), dichloromethane (DCM) and 70% ethanol (EtOH). Cold water and boiled (decoction) extracts of the plant materials were prepared non- sequentially. Among the extracts, EtOH yielded the highest amount of plant substances. A total number of 85 extracts were evaluated for antibacterial activity, 80 for antifungal activity, 64 for anti-inflammatory activity, and 27 biologically active extracts were tested for genotoxicity. The microdilution method was used to determine the minimum inhibitory concentration values in the antibacterial assay against two Gram-negative bacteria (Escherichia coli ATCC 11775 and Klebsiella pneumoniae ATCC 13883) and two Gram-positive bacteria (Bacillus subtilis ATCC 6051 and Staphylococcus aureus ATCC 12600). A modified microdilution method was used to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values in the antifungal assay against Candida albicans. Cyclooxygenase assay was used to evaluate the anti-inflammatory activity of the extracts against cyclooxygenase-1 and -2 (COX-1 and COX-2) enzymes. The plant extracts were screened first at a concentration of 250 ƒÊg/ml per test sample, and then further screened at concentrations of 125 and 62.5 ƒÊg/ml for extracts that inhibited the COX-2 enzyme. The Ames test was used to test for genotoxicity in extracts that showed interesting pharmacological activities using Salmonella typhimurium strain TA98. Among the screened extracts, 25 extracts showed good antibacterial activity with MIC values . 1.0 mg/ml. Dichloromethane extracts exhibited the greatest antibacterial activity, and Gram-positive bacteria were most susceptible. The best antibacterial activity was exhibited by Becium obovatum leaf EtOH extracts with an MIC value of 0.074 mg/ml. A broad spectrum antibacterial activity was observed by leaf extracts of Cucumis hirsutus (PE), Haworthia limifolia (PE), Protea simplex (PE and DCM) and Dissotis princeps (EtOH) against both Gram-negative and Gram-positive bacteria. No interesting antibacterial activity was exhibited by water extracts with the exception of Dissotis princeps water extract with a good antibacterial activity against Gram-positive and Gram-negative bacteria. In the antifungal assay, 6 extracts showed interesting antifungal activity. Protea simplex leaf PE extract showed the best fungicidal activity with an MFC value of 0.014 mg/ml. The best overall antifungal activity was observed in plant EtOH extracts. Some extracts from Agapanthus campanulatus (leaves and roots), Dissotis princeps (leaves), Gladiolus dalenii (corms) and Protea simplex (leaves) showed good activity against Candida albicans. Twenty one extracts inhibited the COX-1 enzyme, while fifteen extracts inhibited the COX-2 enzyme at the lowest screening concentration of 62.5 ƒÊg/ml. The highest COX-1 inhibition at a concentration of 62.5 ƒÊg/ml was exhibited by Diospyros lycioides leaf PE extract (89.1%) while Agapanthus campanulatus root DCM extract showed the highest COX-2 inhibitory activity (83.7%) at the same concentration. In the Ames test, no genotoxicity was observed in any of the extracts, however more tests need to be done to confirm these results. Thin layer chromatograms of the organic solvent plant extracts were developed. The fingerprints of the plant extracts showed colours of bands at different Rf values when viewed under UV254 and UV366 suggesting that the investigated plant species contained different compounds in the extracts. In the quest to understand the source of the plants pharmacological activities, total phenolic compounds including condensed tannins, gallotannins and flavonoids were quantitatively investigated in terms of their amounts in the aqueous methanol extracts of the plants materials using spectrophotometric methods. Alkaloids and saponins were qualitatively determined. The amounts of total phenolics were determined by the Folin Ciocalteu assay, condensed tannins were determined by the butanol-HCl assay, while rhodanine and vanillin assays were used to determine the amounts of gallotannins and flavonoids respectively. Dragendorff reagent was used to detect alkaloids in the plant extracts on thin layer chromatographic plates, while the froth test was employed to detect saponins. Secondary metabolites varied with plant parts and species with Cyperus textilis (leaf) having the highest amounts of total phenolics, condensed tannins and flavonoids. The highest amount of gallotannins was detected in Protea simplex leaf extracts. All the investigated plant materials with the exception of Haworthia limifolia leaf, Protea simplex leaf, Antidesma venosum leaf and Dissotis princeps leaf tested positively to saponins. Alkaloids were detected in Haworthia limifolia leaf (PE and EtOH), Cucumis hirsutus leaf (EtOH), Becium obovatum root (DCM), Protea simplex root and bark (EtOH), Agapanthus campanulatus root (DCM) and leaf (EtOH), Cyperus textilis root (DCM), Vernonia natalensis leaf (PE), Antidesma venosum leaf (PE), Diospyros lycioides leaf (PE) and Dissotis princeps leaf (DCM) extracts. The results obtained from the investigation of the pharmacology and phytochemistry of the plant species used to treat microbial infections related to gastro-intestinal tracts, provide sufficient preliminary information to validate the use of some of the plants in traditional medicine. The information provided might be considered sufficient for further studies aimed at isolating and identifying the active compounds in the plant species, and evaluating possible synergism amongst the isolated compounds. / Thesis (M.Sc)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
356

Understanding Tsonga tradicional [i.e. traditional] medicine in the light of Jesus' healings..

Titoce, Isaias Paulo. January 2002 (has links)
Religion and culture always go together. From the very first day a new person is brought out into this world, s/he starts learning how to live with her or his people, and starts learning their beliefs and values. The person grows up with this knowledge, and it forms a part of his/her life. These beliefs and values are unquestionable from the perspective of that person. They are accepted as natural and normative. If s/he, for example, is brought up in a culture in which kneeling is a form of showing respect, s/he will internalise this, and will always kneel when the act of showing respect is required. For another person who is brought lip in a different culture where standing lip, for example, is regarded as the way of showing respect, kneeling or sitting before a respected individual or occasion can be regarded by a such person as an impoliteness. As we can see, cultural values are subjective, and they are appropriate for the people of a specific culture in which they were fashioned and accepted as normative. What often happens is that when two different cultures meet there is a collision between them, and what often happens is that the one which is supported by power smashes the other and imposes its normative rules on it. When Christianity came to Africa, it was full charged by European way of viewing the world, and in its worldview, anything which was not within the European cultural nornlative frame, was something to get rid of Consciously or unconsciously, Christianity was used as a powerful tool for the West's cultural domination over Africans. The Church demonised African culture, and regarded it as a prototype of anti-Christianity. To become Christians, Africans were required to forsake their life style and assimilate the Western style of living. Things such as drums, xylophones, which were part of African culture, were associated with the demons and thus banned from the lives of the "faithful" African Christians. The memorial ceremonies, which were held for our ancestors, were understood as being a form of idolatry, whereas the church's memory of the saints was regarded as something very Christian. And, if the African culture and practices were abominable for the Western Christian missionaries, its traditional health care system was seen as the ultimate manifestation of the evil. [t is with the desire of reclaiming the legitimacy of African traditional health care system for Africans that 1 set out to examine healing from a cross-cultural perspective, and above all healing in the Bible, and specially Jesus' healings in order to see what is abominable with African traditional medicine. / Thesis (M.Th.)-University of Natal, Pietermaritzburg, 2002.
357

Seed germination and medicinal properties of Alepidea species.

Mulaudzi, Rofhiwa Bridget. January 2009 (has links)
The rhizomes of Alepidea amatymbica and Alepidea natalensis are used for medicinal purposes. Because of the increase in demand for these plants the species is becoming scarce. As the seed biology of neither species is well defined, conditions as well as treatments required for optimum germination and vigour were studied. Seeds were exposed to various physical factors such as varying light and temperature conditions and cold stratification, sowing depth and seed storage. The effects of smoke-water, butenolide (3-methyl-2H-furo [2, 3-c] pyran-2-one) a novel smoke compound and chemical substances (gibberellins, kinetin and KNO3) were also tested in order to improve seed germination. Alepidea amatymbica and A. natalensis achieved the highest seed germination (72.5% and 80%, respectively) at 25 °C under a 16 h photoperiod with a mean germination time (MGT) of 18 and 12 days, respectively. Phytochrome studies showed that A. natalensis requires light for germination. Cold stratification (5 °C) for 14-28 days significantly improved the percentage germination of both species (> 90%) compared to non-stratified seeds (control) at 25 °C under a 16 h photoperiod. Sowing A. amatymbica and A. natalensis seeds at a depth of 0.5 cm resulted in higher percentage germination compared to 2.5 cm. The highest emergence rate for A. amatymbica was 40% at a sowing depth of 0.5 cm and the lowest emergence rate was 3% at 2.5 cm. Six months storage of A. natalensis seeds at room temperature (25 ± 2 °C) showed maximum germination (99%) with a MGT of 9 days. Smoke-water treatment of A. amatymbica seeds significantly enhanced germination from 72% to 91%. Smoke and butenolide at 10 °C and 25 °C promoted germination of A. natalensis seeds in a 16 h photoperiod. Smokewater application significantly improved both germination and seedling vigour of A. natalensis. GA3 (10-8 M) was the best treatment for achieving maximum percentage germination of A. natalensis seeds. Antibacterial (two Gram-positive bacteria: Bacillus subtilis, Staphylococcus aureus and two Gram-negative bacteria: Escherichia coli, Klebsiella pneumoniae), antifungal (Candida albicans), anti-inflammatory (COX-1 and -2) and genotoxicity tests (Ames test) were carried out on petroleum ether (PE), dichloromethane (DCM), 80% ethanol (EtOH) and water extracts of the two Alepidea species. Water extracts of A. natalensis rhizomes exhibited high activity (MIC values of 0.78 mg/ml) against the four bacterial strains. High activity was also observed in the PE and DCM leaf extracts of the same plant against the Gram-positive bacteria. The PE and DCM extracts of A. amatymbica rhizomes exhibited the best activity (MIC values of 0.39 mg/ml) against Bacillus subtilis. The rest of the extracts showed low activity (MIC values >1 mg/ml). All the extracts showed activity against Candida albicans, with A. natalensis leaf extracts exhibiting the highest antifungal activity with MIC values of 0.88, 0.20 and 0.78 mg/ml for PE, DCM and EtOH, respectively. EtOH extracts had inhibition less than 40% for both A. natalensis and A. amatymbica. All the PE extracts showed higher inhibitory activity for COX-2 than for COX-1. PE and DCM extracts had percentage inhibitions above 70% in both COX-1 and COX-2 assays. The Ames test for genotoxicity revealed that none of the plant extracts were genotoxic to the Salmonella TA98 tester strain. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
358

Pharmacology and phytochemistry of South African plants used as anthelmintics.

Aremu, Adeyemi Oladapo. January 2009 (has links)
Traditional medicine in South Africa is part of the culture of the people and has been in existence for a long-time. Although animal components form part of the ingredients used, plant material constitutes the major component. South Africa is endowed with vast resources of medicinal and aromatic plants which have been employed for treatment against various diseases for decades. A large number of South Africans still depend on traditional medicine for their healthcare needs due to its affordability, accessibility and cultural importance. Helminth infections are among the variety of diseases treated by traditional healers. These infections are regarded as neglected tropical diseases (NTDs) due to their high prevalence among the economically disadvantaged living in rural areas in different regions of the world. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
359

In vitro bulb induction in Eucomis zambesiaca Baker.

Cheesman, Lee. January 2009 (has links)
Eucomis L’ Hér. is a genus of 10 species that fall within the Hyacinthaceae family. Eucomis zambesiaca Baker is a summer-blooming bulbous geophyte occurring from northern South Africa to Malawi. Eucomis species are used in southern African traditional medicine for the treatment of various ailments, in particular, pain and inflammation. As a result, the bulbs are heavily harvested for trade in South Africa’s traditional ‘muthi’ markets. Over-collection of Eucomis species has seriously depleted natural populations and now Eucomis plants are among the 15 scarcest medicinal species to be traded. Micropropagation is a useful technique for rapid clonal multiplication of plant material which could potentially yield useful secondary metabolites as well as alleviate the pressure on the wild plant populations. The in vitro induction of storage organs is especially beneficial as it can limit the loss of plants during acclimatization as bulblets are hardier than shoots or plantlets. The aim of this research was to determine optimal growth conditions for bulblet induction of Eucomis zambesiaca. The effect of environmental and physiological parameters on the initiation and growth of bulblets was investigated. These included the effect of temperature, photoperiod, various carbohydrates at different concentrations and combinations as well as various plant growth regulators. Maximum number of bulblets per explant was obtained at 20 °C, with an average of three bulbs p er leaf explant. The average bulblet mass was 57 mg, which was significantly higher than bulblets formed at other tested temperatures. An 8 h light regime was the optimum photoperiod. The highest mean number of bulblets (1.4 per leaf explant) developed under the 8 h photoperiod and the bulblets that formed were large in size. They had a mean bulb diameter of 3.4 mm and a mean bulb weight of 42 mg. Different carbohydrates such as fructose, sucrose and glucose were tested at concentrations of; 1, 3, 6, 9 and 12%. Fructose at a concentration of 3% was found to produce the best results. An average of 1.2 bulbs formed per explant. The mean bulb diameter was 3.4 mm and mean bulb weight was 56.6 mg. Plant growth regulators (GA3, IAA, IBA, NAA, BA, zeatin, iP and others) were tested at concentrations of 1, 2 and 5 mg/L. 1 mg/L IBA was found to be the optimum hormone treatment for bulblet induction. Bulblets were large, had good leaves and well established roots. Medium supplemented with 1 mg/L IBA produced bulblets that had an average bulb diameter of 4.36 mm and a mean bulblet weight of 79.1 mg. Bulblets grown in vitro were transferred to vermiculite and placed in a misthouse to acclimatize. After 2 months the plantlets were transferred to pots containing a sand:soil mixture of 1:1 and placed in a greenhouse. There was a 80 to 90% survival rate. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
360

Ethnobotanical study of plants from Pondoland used against diarrhoea.

Madikizela, Balungile. January 2012 (has links)
Diarrhoea and related diseases are the most common causes of death in children, especially from developing countries, killing about 1.5 million children under the age of five yearly. In South Africa, diarrhoea is the third leading cause of death. This condition results from food and water sources infected with Campylobacter spp., Escherichia coli, Salmonella spp., Shigella spp., Giardia intestinalis and Cryptospondium parvum amongst others. Diarrhoea spreads through faeces-contaminated water. Hence, infection is more common when there is a short supply of clean drinking and cooking water. Waterborne diseases are common in rural communities of Bizana because the majority of rural dwellers depend largely on water from unprotected sources. Most of the pathogens that cause diarrhoea have developed resistance to several antibiotics. Therefore there is a need for new and safe antidiarrhoeal drugs. Most people in developing countries use traditional medicine to treat all kinds of diseases including diarrhoea and South Africa is no exception. Each cultural group in South Africa has different medical solutions for the prevention and curing of the same disease. The people from Pondoland (AmaMpondo), around Bizana have a strong tradition of using medicinal plants for the cure and prevention of several conditions including diarrhoea. Although several researchers have conducted different types of studies in many parts of South Africa to evaluate the efficacy of traditional medicine used in the treatment of diarrhoea, there is, however, still a lot of undisclosed data that should be collected. The aims of this research were to record and collect medicinal plants that are used for treating diarrhoea in Bizana, Pondoland in the Eastern Cape and evaluate them for their pharmacological properties. An ethnobotanical approach is one of several methods that have been useful in selecting plants for pharmacological research, yielding better results than other plant selection methods. Using questionnaires, this approach was used to record plants that are used for treating diarrhoea in Bizana for testing in pharmacological assays. From the completed questionnaires, nine plants were selected for bioassays based on their higher frequency index, and the fact that the plants have never been evaluated against diarrhoea causing-microorganisms. The study revealed 34 plant species belonging to 21 families as being used in treatment of diarrhoea in the study area. Psidium guajava was the most mentioned plant species. The dried, ground plant materials were each extracted non-sequentially using petroleum ether (PE), dichloromethane (DCM), 70% ethanol (EtOH) and water. Among all the extracts, 70% ethanol yielded the highest quantity of crude extract. The extracts were each evaluated for their antibacterial, anti-inflammatory and genotoxicity properties. For the antibacterial activity, the following diarrhoea causing microorganisms were used: Gram-positive Staphylococcus aureus and Gram-negative Campylobacter jejuni, E. coli and Shigella flexneri. A microdilution assay (for S. aureus, E. coli and S. flexneri) and the disk diffusion technique (for C. jejuni) were used for antibacterial testing. The extracts were also evaluated for their ability to inhibit cyclooxygenase (COX-1 and -2) enzymes. Genotoxicity was evaluated using the Salmonella microsome assay without S9 metabolic activation. Three strains of Salmonella typhimurium TA98, TA1535 and TA1537 were used. The evaluated plant extracts showed a broad spectrum of inhibitory activity with MIC values ranging from 0.098-12.5 mg/ml and mean zone inhibition percentage ranging from 0-73%. The best activity was exhibited by DCM extracts of Rapanea melanophloeos, EtOH extracts of Ficus craterostoma and Maesa lanceolata with MIC values of 0.098 mg/ml and EtOH extracts of Searsia chirindensis with 73% mean zone inhibition percentage. The inhibitory activity against COX-1 enzyme was higher than COX-2, with 19 plant extracts for the former and 7 for the latter. The highest inhibition of COX-1 was shown by EtOH extracts of F. craterostoma and the DCM extract of S. chirindensis at 100%. Highest percentage COX-2 inhibition was shown by water extracts of F. craterostoma and DCM extracts of Tecoma capensis with 99.5% and 99.0% respectively. None of the tested plant extracts were mutagenic, at all concentrations tested against all tester strains of the bacteria. The results of this study demonstrate that people still have a rich and diverse pool of knowledge concerning the uses of plants against diarrhoea. The data also show that plants form part of the cultural heritage of the communities in Pondoland. Therefore it is important to urgently save the people’s cultural heritage by recording the existing knowledge and confirming therapeutic uses of plants through scientific methods. This will prevent the information from vanishing together with the ageing knowledge holders. In light of the fact that the evaluated plants were selected based on their ethnobotanical use for treating diarrhoea, the activities reported here goes a long way in adding value to the plants used as part of traditional medicine. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

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