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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.
1

Effects of micronutrients on growth and quality of bush tea (Athrixia phylicoides DC.)

Maedza, Khathutshelo Vuwani 20 April 2016 (has links)
Bush tea (Athrixia phylicoides DC.) is a herbal beverage and medicinal plant indigenous to South Africa. A trial was conducted to determine the effect of micronutrients on the plant growth and quality of bush tea. The trial was laid out in a completely randomized block design with five replicates. Treatments consisted of single applications of Zinc (Zn), Copper (Cu), Boron (Bo), Iron (Fe) and Magnesium (Mg) at three levels (50ml/l, 100ml/l and 150ml/l) and a combination of all micronutrients. A control treatment with no spray was also included. Leaf analysis was conducted using Varian Liberty series II instrument. Total polyphenols were determined using the Folin Ciocalteau method and tannins were determined using Vanillin HCl method. Bush tea samples (one leaf per sample) were analysed using head space solid phase micro-extraction gas chromatography (HS-SPME-GC-MS). Results of this study demonstrated that application of micronutrients increased the total polyphenols, tannins and total flavonoids in bush tea, with most of the increase in total polyphenols (77.5-93.7 mg/g) occurring in combination B + Zn + Fe + Cu + Mg treatment, increase in tannins (87.3-99.5 mg/g) occurring in copper treatment and increase in total flavonoids (164.6-176.6 mg/g) occurring in mixture (B + Zn + Fe + Cu + Mg) treatment. Results also show a significant increase in the quality and plant growth of bush tea. Five major compounds were identified (>80% identification probability) namely alpha-pinene, beta-pinene, myrcene, beta-caryophyllene and caryophyllene oxide. Linear relationship between percentage leaf tissues and treatments levels of micronutrients in bush tea was also observed. Boron and copper treatments showed strong linear correlation with a positive relationship between treatments levels and leaf percentage. Therefore, for improved total polyphenols content in bush tea leaves, a combination of (B + Zn + Fe + Cu + Mg) is recommended. Tannin content in bush tea leaves were significantly increased at Cu50 ml/l, Cu100 ml/l and Cu150 ml/l. For improved total flavonoids content in bush tea leaves, a combination of foliar spray of (B + Zn + Fe + Cu + Mg) is recommended. The LC-MS observations from the study showed no significant qualitative difference between control and micronutrient treatments with these treatments showing similar number of peaks. There was a significant quantitative difference between control and where magnesium peaks applied at adequate rates at (50 ml/l and 100 ml/l) and combination of (B + Zn + Fe + Cu + Mg) applied at (10 ml/l and 20 ml/l) / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)
2

Effect of fermentation temperature and duration on chemical composition of Bush tea (Athrixia phylicoides DC.)

Hlahla, Linda Noble 12 1900 (has links)
Thesis (M.Sc.) --University of Limpopo, Turfloop Campus, 2010 / A study was conducted to determine the effect of fermentation temperature and duration on chemical composition of bush tea (Athrixia phylicoides DC.). Bush tea was fermented in incubators at different temperatures and for different lengths of time for quality improvement. Treatments for fermentation temperature consisted of control (24°C; room temperature), 30°C, 34°C, 38°C and 42°C where the tea leaves were fermented for 30 minutes. Treatments for fermentation time consisted of control (0), 60, 90, and 120 minutes at an incubator temperature of 22-26°C. A completely randomized design (CRD) was used with three replicates for both evaluations. The chemical analysis (polyphenols, tannins and antioxidants) were done using Waterman and Mole (1994) method. The results of this study demonstrated that fermentation temperature significantly increases polyphenols at 30, 34, and 38°C whereas tannin content showed a great reduction at 38 and 42°C. Increasing fermentation time achieved a significant increase in both polyphenols (60 and 90 minutes) and tannin contents (90 and 120 minutes). However, changes in either fermentation temperature or time did not give any significant influence on antioxidant content of bush tea. / National Research Foundation
3

Effects of brewing temperature and duration on quality of black tea (Camellia sinensis) and equal (50:50) combination of bush tea (Athrixia phylicoides DC.) and black tea.

Negukhula, Shonisani 12 1900 (has links)
Thesis (M.Sc)--University of Limpopo, 2010. / Black tea (Camellia sinensis) and black tea combined with bush tea (Athrixia phylicoides) were analyzed for their polyphenol content, antioxidant activity and tannin content. Solvent extraction methods were used for extracting polyphenols, antioxidant activity and tannin content. Total phenols were determined using the Folin-Ciocalteu method, antioxidant activity using Trolox Equivalent Antioxidant Capacity (TEAC) assay and tannin content using vanillin-HCl method. Polyphenol content, antioxidant activity and tannin content were calculated using regression equation Y=MX+C, where C=intercept, Y= Absorbance of the sample and M= Gradient. Results of black tea in this study showed that total polyphenols, antioxidant activity and tannin content decreased with decrease in temperature and time and this was attributed to the release of polysaccharides at 90°C. At 90°C for 3 minutes 7.68mg/100g of total polyphenol, 3.85μmol/g of antioxidants and 2.81mg/100g of tannin were obtained and this amount decreased to 5.50mg/100mg for total polyphenols, 1.31μmol/g for antioxidant activity and 0.72mg/100mg for tannin content at 30°C for 10 minutes. Combining the two tea types (50:50) resulted in a significant (p<0.005) decrease in total polyphenols, antioxidant and tannin content. Results of this study showed that at high temperature of 90°C for 3 minutes 2.64mg/100g for total polyphenol, 2.48μmol/g for antioxidants and 1.8mg/100g for tannin were obtained and these amounts decreased to 1.39mg/100mg for total polyphenols, 0.35μmol/g for antioxidant activity and 0.64mg/100mg for tannin content at 30°C for 10 minutes. Thus high brewing temperature causes increase in total polyphenols, antioxidant activity and tannin content of the combined teas. This study showed that black tea and combined black tea and bush tea solutions had large TEAC radical scavenging activity which can be related to total polyphenols and catechins. The antioxidant activity of the tea solution increased with increase in extraction temperature and duration of soaking. It is recommended that 3-min soaking temperature of 90 °C of black tea and combined bush tea and black tea can be used due to the highest total polyphenols and antioxidant activity obtained.
4

Chemical profiles of bush tea (Athrixia phylicoides DC.) at different phenological stages and as influenced by pruning and growth regulators.

Maudu, Mpho Edwin 12 1900 (has links)
Thesis(M.Sc)--University of Limpopo, 2010. / Bush tea (Athrixia phylicoides DC.) has received interest as another indigenous South African herbal tea with potential for commercialization. The success of commercialization of bush tea hinges on maintenance or enhancement of quality of bush tea as a herbal beverage. Herbal tea quality is one of the critical factors in commercialization that would determine the price of tea for local sale and export. A research was conducted to determine chemical profiles of bush tea at different phenological stages and as influenced by pruning and application of growth regulators. A trial to determine the quality of tea harvested at various phenological stages (namely new growth, older growth and whole plants) from wild and cultivated bush tea was conducted. This was to help determine the best phenological stage to harvest bush tea of best quality. In cultivated bush tea, harvested new growth or as whole plants proved to be of higher quality owing to their higher polyphenol and tannin attributes respectively. In wild bush tea, both new and older growth proved to be of good quality owing to the higher total polyphenol content and higher total antioxidants, respectively. A trial to determine the effect of pruning at different heights on growth and quality of bush tea was also conducted. Pruning of bush tea largely led to yield reduction. Unpruned tea plants remained the tallest plants, with higher number of branches, bigger leaf area and a larger biomass than apically, middle and base pruned bush tea plants. Pruning at different heights also proved to have little or no effect on quality of bush tea. While only total polyphenols remained higher in unpruned tea plants, no significant differences were observed in tannin and total antioxidant content in unpruned, apically, middle and base pruned tea plants. A third trial was conducted to investigate the effects of gibberellins on sprouting and quality of bush tea. The trial results showed that gibberellin application had a iv favourable effect on growth of bush tea, with application of 3% and 4% yielding the highest growth. The results also indicated a declining total polyphenol and antioxidant content with increasing gibberellin application rate, while tannins peaked at 2% application rate.
5

Seed germination and vegetative propagation of bush tea (athrixia phylicoides)

Araya, Hintsa Tesfamicael 09 February 2006 (has links)
Bush tea (Athrixia phylicoides) is an herbaceous plant of the Asteraceae family used throughout history as medicinal herbal tea by the people of South Africa. Many studies stated that the plant has an ability to be commercialized as a medicinal herbal tea. But vegetative propagation of this type of plant by stem cutting, survival ability of the rooted cuttings, response to different hormone concentrations and the requirement of the seeds for germination has not been studied. In this investigation, different features aimed at effective propagation of bush tea were studied. These comprised: cutting position (apical vs. basal), media (pine bark vs. sand), hormone (Seradix No. 2), season (summer, autumn, winter and spring), transplanting survival of rooted apical and basal cuttings, response of basal cuttings to three hormone concentration levels (Seradix No. 1, 2 and 3) and light and temperature requirement for bush tea seed germination. In vegetative propagation, apical cuttings rooted to higher percentage and produced high root number as well as longer roots than basal cuttings. Pine bark improved the number of roots developed but had no effect on rooting percentage as well as root length. Application of rooting hormone (Seradix No. 2) increased root numbers but not rooting percentage or root length. Rooting of cuttings was improved when propagated in autumn (longer roots) and spring (more number of roots) than in summer or winter. There was higher survival percentage (67.5%), high root number as well as longer roots from apical cuttings than from basal cuttings (50%) two months after transplanting. Propagation in pine bark with hormone application increased root number after transplanting. Application of hormone also improved root and shoot length after transplanting. Apical cuttings propagated in pine bark with hormone developed more number of roots. Cuttings propagated in sand with hormone and in pine bark without hormone also produced longer shoots after transplanting. Regarding response of basal cuttings to hormone concentration, high number of roots was produced in pine bark with Seradix No. 2 at 10 days after planting (DAP) but at 15 DAP more roots were produced in pine bark with Seradix No. 1. With sand, more roots were produced with Seradix No. 3 than Seradix No. 1 and 2. Number of roots were also higher with 0.3% IBA concentration (Seradix No. 2) and 0.1% IBA concentration (Seradix No. 1). Similarly, cuttings with lower IBA concentration (0.1%, Seradix No. 1) rooted to higher percentage followed with 0.3% IBA concentration (Seradix No. 2). Germination percentage of bush tea seeds differed with the temperature treatments and the highest was 75.5% at 20 and 25°C followed by 15°C with 64.5% and low percentage at 30 and 10°C with 36 and 47% respectively. There was a high germination percentage in constant temperatures than alternate temperatures and in continuous light than alternate light: dark or continuous dark. Germination percentage was also higher in continuous light at constant temperatures than with alternated light: dark with constant temperatures. In addition, there was more differences in germination percentage with variation in light exposure than variation in temperatures. At low temperature (10°C), longer time was required to start germination and germination rate was high at 20°C continuous light and low at 30:30°C alternate light: dark. Based on this investigation, better vegetative propagation and survival of bush tea can be attained from apical cuttings with Seradix No. 2 but basal cuttings rooted better with Seradix No. 1 in pine bark. Seeds germinated to higher percentage and rate at 20°C constant temperature and continuous light. / Dissertation (MSc (Agric) Horticulture)--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted
6

Antioxidant and antibacterial activities of ethanol extract and flavonoids isolated from Athrixia phylicoides

Mavundza, Edison Johannes 01 July 2011 (has links)
The ethanol extract of A. phylicoides was investigated for its antioxidant activity using the DPPH scavenging method. The extract showed good antioxidant results with a EC50 value of 10.64 ± 0.0842 µ/ml. The extract was also tested for antibacterial activity against microorganisms (Staphylococcus aureus, Enterococus faecalis, Bacillus cereus, Bacillus subtilis, Bacillus pumilus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia) commonly known to pose a threat in the wellbeing of man. All tested microorganisms were significantly inhibited by the extract with the MIC values ranging from 3.13 µg/ml to 6.25 µg/ml. Folin-Ciocalteu’s reagent method was used to determine total phenolic content of dried and freshly prepared crude extract of A. phylicoides. Higher total phenolic content (28.28 ± 0.019 mg GAC/100g) and antioxidant activity (EC50, 10.64 ± 0.084 µg/ml) was observed in the dried extract compared to the fresh extract with a TPC value of 23.04 ± 0.003 mg GAC/100g and EC50 of 13.97 ± 0.066 µg/ml. Bioassay-guided fractionation of ethanolic extract from aerial parts of Athrixia phylicoides using silica and sephadex column chromatography led to the isolation of four known flavanoids, 5-hydroxy-6,7,8,3’,4’,5’-hexamethoxyflavon-3-ol (1), 3-0- demethyldigicitrin (2), 5,6,7,8,3’,4’-hexamethoxyflavone (3) and Quecertin (4). Due to the low yield, no further tests were done on compound 3. A DPPH-scavenging assay was performed to evaluate the antioxidant activity of the isolated compounds. All the tested compounds showed potent antioxidant activity with EC50 values ranging from 1.27 to 3.41 µg/ml. Compound 4 showed a higher antioxidant activity (EC50, 1.27 µg/ml) than vitamin C (EC50, 2.66 µg/ml) used as a control. The MIC values of the isolated compounds against tested microorganisms varied from 20 to more than 40 µg/ml. All the tested compounds showed no activity against S. aureus, B. pumilus, K. pneumonia and P. aeruginosa at the highest concentration tested (40 µg/ml). These compounds together with the extract were further analyzed by XTT assay on Vero cells. The extract showed a low toxicity effect on the cells at lower concentrations exhibiting EC50 value of 107.8 ± 0.129 µg/ml. Compound 4 showed minimal toxicity effect on the cells with a EC50 value of 81.38±0.331 µg/ml, compared to Compound 1 and 2 which exhibited EC50 values of 27.91 ± 0.181 µg/ml and 28.92 ± 0.118 µg/ml respectively. The results obtained from this study provide a clear rationale for the medicinal uses of Athrixia phylicoides. / Dissertation (MSc)--University of Pretoria, 2010. / Plant Science / unrestricted
7

The phytochemistry and biological activities of Athrixia Phylicoides

Padayachee, Kumeshnie 27 October 2011 (has links)
Herbal medicines are an important part of the African culture and tradition and about 80% of Africa’s population relies on traditional remedies for their primary health care needs (WHO, 2008). Athrixia phylicoides is widely used as a traditional remedy, but despite its substantial use, literature on its chemical composition and biological activities is limited. In this study, the chemical composition of the essential oil was determined using gas chromatography combined with mass spectroscopy (GC/MS) and analysis resulted in the identification of 182 compounds. The major compounds identified in selected samples were α-pinene, β-pinene, caryophyllene oxide, β-caryophyllene, myrcene and spathulenol. Based on the traditional uses of A. phylicoides, various in vitro biological activities were investigated. The extensive use of A. phylicoides for the treatment of boils, sores, bad acne, infected wounds and cuts, prompted the antimicrobial (bacterial and fungal) study using the minimum inhibitory concentration (MIC) assay. The methanol extract and essential oil were more selective for the Grampositive bacteria than the Gram-negative bacteria. The extract exhibited stronger activity against all micro-organisms tested compared to the essential oil, with the highest activity against S. aureus, B. cereus and B. subtilis (MIC = 1 mg/ml). The bioactive compound, (4-hydroxyphenyl) propyl coumaroate was isolated from the extract and proved to be most active against S. aureus (MIC = 19.5 μg/ml). Using the DPPH• assay, a comparative antioxidant study was performed. The anti-oxidant activity of the aqueous extract of A. phylicoides (IC50 = 14.01 ± 2.68 μg/ml) was greater than rooibos and Ceylon (black) tea (IC50 > 25.00 μg/ml); comparable to green rooibos and honeybush tea (IC50 = 18.01 ± 4.06 μg/ml; 18.02 ± 4.27 μg/ml, respectively), but less active than green tea (IC50 = 9.64 ± 0.96 μg/ml). The antimalarial activity was determined using the [3H] hypoxanthine incorporation method. The essential oil exhibited greater antimalarial activity against the chloroquine-resistant Plasmodium falciparum (FCR-3) strain (IC50 = 1.006 ± 0.06 μg/ml) than the methanol extract. The 5-lipoxygenase assay was used to assess the anti-inflammatory activity of the methanol extract and essential oil. Only the essential oil displayed anti-inflammatory activity (IC50 = 25.68 μg/ml). Low safety indices were reported for both the methanol extract (SI = 2.28) and essential oil (SI = 1.77). The in vitro biological activities may validate the use of A. phylicoides in traditional medicine.
8

Effects of different climatic and soil factors at different locations on chemical composition of bush tea (Athrixia phylicoides DC.)

Nchabeleng, Lehlohonolo January 2012 (has links)
Thesis (M.Sc. (Horticulture)) --University of Limpopo, 2012 / Refer to document / the National Research Foundation
9

Indigenous knowledge of bush tea (Athrixia Phylicoides) and effect of fertigation frequency and growing medium on plant growth

Rakuambo, Z.J. (Zwonkunda Juliet) 04 August 2008 (has links)
Bush tea (Athrixia phylicoides) is a medicinal herbal tea, which is used for cleansing or purifying the blood, treating boils, bad acne as well as infected wounds and cuts. A. phylicoides also has the potential to be used as an ornamental cut flower due to its beautiful flowers. Because of the many uses of bush tea, it faces problems of being over harvested and exploited. Therefore, there is a need to study more about the plant for possible domestication. A questionnaire survey was conducted in selected villages of Thohoyandou and Nzhelele in Venda, Limpopo Province, by means of personal interviews. The aim of the survey was to gather indigenous knowledge and validate the uses of bush tea from the local people. Interviews were conducted on three types of respondents, viz. traditional healers (31%), street sellers (25%) and bearers of indigenous knowledge (44%). A total of one hundred respondents were interviewed. One important finding of the study was that people from the area of study possess a remarkable knowledge of the plant and its uses to treat a wide range of physical ailments. The bush tea plant is used as medicine, health tea as well as a traditional broom. Some of these ailments that could be treated using bush tea were headaches, stomachache, influenza and leg wounds. It is known to have aphrodisiac properties and it can also be used to cleanse the womb, kidney, and veins and to purify blood. The plant was harvested in different ways depending on the reason for harvesting. Results from the survey indicated that the majority of the respondents had no interest in propagating the bush tea plant, few respondents showed interest in propagating the plant. They also showed enhanced knowledge about the uses of other medicinal plants. A tunnel experiment was also conducted at the Hatfield Experimental Farm of the University of Pretoria in South Africa. The effects of growing media (pine bark and sand) and fertigation frequencies (0.4 ℓ/day, 1 ℓ/day, 2 ℓ/day, 2 ℓ/2nd day and 2 ℓ/ week) on growth and yield of bush tea were studied. Growing media and fertigation frequencies significantly affected the growth performance and yield of bush tea. The growth rate of bush tea between the autumn season and winter season was higher than between winter and spring season. Greater number of stems and shoots were observed in sand grown plants as compared to pine bark grown plants. Sand grown plants had a higher root mass as compared to those of pine bark grown plants over both seasons, with nonsignificant differences in the dry root mass in winter (90 days after planting). Plants grown in sand had significantly longer roots (P≤ 0,05) than plants grown in pine bark at 90 days after planting. However, at 180 days after planting the differences in root lengths were no longer significant. Fertigation frequencies caused significant differences in growth performance and yield of bush tea. Plants fertigated with 1 ℓ/day were significantly the tallest, followed by plants fertigated with 0.4 ℓ/day, 2 ℓ/day, 2 ℓ/2nd day and 2 ℓ/ week. Our results confirmed that bush tea could grow up to 1 metre high (1.08 m). In addition, fertigation frequency of 1 ℓ/day resulted in plants with greater stem and leaf mass (both fresh and dry), thus higher yields. Fertigation frequency of 2 ℓ/day was found to be too high and hence reduced oxygen supply to the roots and consequently retarded above plant growth. Sand grown plants also produced more flowers than pine bark grown plants. Overall, plants grown in sand media had superior stem and shoot mass, leaf mass, root mass and flower mass compared to plants grown in pine bark. Plants that received insufficient amount of water (2 ℓ /week) resulted in stunted growth and produced the least yield. In conclusion, bush tea plants performed better in sand growth media than in pine bark growth media. An optimum application rate of 1 ℓ/day was ideal for growth and performance of bush tea as the plant performed better under this fertigation frequency. / Dissertation (MInstAgrar)--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted
10

Use of the Athrixia phylicoides plant in Tshwane: an anthropological study

Siko, Maggie Ngwanamaphoto 02 1900 (has links)
This study focuses on the use of the Athrixia phylicoides plant in Tshwane, Gauteng, South Africa. The plant is used within the domestic domain as a beverage, for medicinal purposes, as well as for the manufacturing of domestic brooms. The aim of the study was to investigate the use and market of Athrixia phylicoides in two of the Tshwane markets, namely; Denneboom and Marabastad. Case study design, participant observation and interviews were employed to collect data. A literature review was conducted to construct a theoretical framework. The study reveals that traditional healers, broom makers and customers have a remarkable knowledge about Athrixia phylicoides, which has been untapped thus far. In addition, the study indicates that possible extinction of the Athrixia phylicoides plant, due to over-harvesting and lack of conservation, will pose a challenge to the market. / Anthropology / M.A. (Anthropology)

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