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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.
41

Variation in the essential oil composition of Calendula Officinalis L

Okoh, Omobola Oluranti January 2008 (has links)
Variations in the yield, chemical composition, antibacterial, and antioxidant properties of the essential oils of Rosmarinus officinalis L. cultivated in Alice, Eastern Cape of South Africa over a period of 12 months using the solvent-free microwave extraction and traditional hydrodistillation methods were evaluated. The GC-MS analyses of the essential oils revealed the presence of 33 compounds with 1,8-cineole, a-pinene, camphor, verbenone, bornyl acetate and camphene constituting about 80 percent of the oils throughout the period of investigation, with the solvent-free microwave extraction method generally yielding more of the major components than the hydrodistillation method. Each of the major components of the oils varied in quantity and quality of yield at different periods of the year. The method of extraction and time of harvest are of importance to the quantity and quality of essential oil of Rosmarinus officinalis. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene- 4-ol, linalool, a-terpeneol were present in the oil of SFME in comparison with HD. However, HD oil contained more monoterpene hydrocarbons such as a-pinene, camphene, β-pinene, myrcene, a-phellanderene, 1,8-cineole, trans- β-ocimene, γ-teprinene, and cis-sabinene hydrate than SFME extracted oil. Accumulation of monoterpene alcohols and ketones was observed during maturation process of Rosmarinus leaves. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration values were determined using a serial microplate dilution method. The essential oils obtained using both methods of extraction were active against all the bacteria tested at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the SFME extracted oils ranged between 0.23 and 1.88 mg mL-1, while those of the HD extracted oils varied between 0.94 and 7.5 mg mL-1, thus suggesting that the oil obtained by solvent free microwave extraction was more active against bacteria than the oil obtained through hydrodistillation. The antioxidant and free radical scavenging activity of the obtained oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay and β- carotene bleaching test. In the DPPH+ assay, while the free radical scavenging activity of the oil obtained by SFME method showed percentage inhibitions of between 48.8 percent and 67 percent, the HD derived oil showed inhibitions of between 52.2 percent and 65.30 percent at concentrations of 0.33, 0.50 and 1.0 mg mL-1, respectively. In the β-carotene bleaching assay, the percentage inhibition increased with increasing concentration of both oils with a higher antioxidant activity of the oil obtained through the SFME than the HD method. Thin layer chromatography (TLC) was used to analyze the chemical composition of the extracts using three eluent solvent systems of varying polarities i. e. CEF, BEA and EMW and sprayed with vanillin-sulfuric acid. The chemical composition of the different extracts was similar with the exception of methanol and water extracts which had only one or two visible compounds after treating with vanillin-spray reagent. To evaluate the number of antibacterial compounds present in the fractions, bioautography was used against two most important nosocomial microorganisms. S. aureus (Gram positive) and E. coli (Gram negative). Nearly all the crude serial extraction fractions contained compounds that inhibited the growth of E. coli. The hexane extract had the most lines of inhibition followed by ethyl acetate. Bioassay-guided fractionation against E. coli was used to isolate antibacterial compounds. The largest number of antibacterial compounds occurred in the hexane fraction. Furthermore we tried to complete the characterization by extracting and studying other biologically important plant metabolites such as phenolic compounds to evaluate the antioxidant capacity of Rosmarinus extracts
42

Screening of extracts from medicinal plants of Cameroon for antimicrobial activity /

Kwo, Victor T. 01 January 1996 (has links) (PDF)
No description available.
43

Consumer choice behavior and marketing plan for aromatherapy products in Hong Kong.

January 1999 (has links)
by Lam Shiu Ying Sati. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 56-57). / Questionnaire also in Chinese. / Chapter I. --- introduction --- p.1 / Definition of Aromatherapy --- p.1 / Uses of Aromatherapy --- p.2 / Aromatherapy as Alternative Natural Healing --- p.3 / Aromatherapy in Hong Kong --- p.4 / Objective of the Project --- p.5 / Chapter II. --- ENVIRONMENT --- p.7 / brief History of Aromatherapy --- p.7 / Social and Legal Environment on Aromatherapy in the World and Hong Kong --- p.8 / Social Issues --- p.9 / Legal Issues on Selling Essential Oils --- p.11 / Qualification of Aromatherapists --- p.13 / Chapter III. --- INDUSTRY --- p.15 / Aromatherapy Related Products --- p.15 / Market Players in Hong Kong --- p.17 / Chapter IV. --- MARKETING STRATEGIES --- p.26 / The Company --- p.26 / Market Opportunities --- p.28 / Marketing Strategies of Company ABC --- p.29 / Position of Company ABC --- p.29 / Product and Price Considerations --- p.30 / Promotion and Channel Considerations --- p.31 / Potential Problems and Constraints --- p.34 / Chapter V. --- MARKET SURVEY --- p.35 / Chapter VI. --- CONCLUSION --- p.42 / APPENDIX --- p.46 / BIBLIOGRAPHY --- p.56
44

A model to enhance the perceived trustworthiness of Eastern Cape essential oil producers selling through electronic marketplaces

Gcora, Nozibele January 2016 (has links)
Eastern Cape Province farmers in the natural essential oils industry are yet to fully realise the use of electronic commerce (e-commerce) platforms, such as electronic marketplaces (e-marketplaces) for business purposes. This is due to the issues that include lack of awareness, poor product quality, untrusted payment gateways and unsuccessful delivery that are associated with e-marketplaces. As a result, farmers do not trust e-marketplaces and therefore hesitate to engage in e-marketplaces for business purposes. This is further complicated by natural essential oils buyers‟ tendency of preferring face-to-face interaction with a supplier rather than online interaction as they need quality assurance. As such, this research proposes a model to enhance the perceived trustworthiness of natural essential oil producers in the Eastern Cape Province selling through e-marketplaces. The model constitutes the factors that could be considered in assisting essential oil producers to create a perception of trustworthiness to buyers in e-marketplaces. These factors were evaluated amongst five organisations involved in the production, retail or processing of essential oils using a multiple-case study methodology. The study‟s use of multiple-case study was applied within the interpretivist paradigm and five cases were considered. Interviews, document analysis and observations were used for data collection. Data analysis was done using within-case analysis followed by cross-case analysis to establish factors of trust. The essential oil producers based in the Gauteng, Kwazulu-Natal and Western Cape provinces were cases that had been successfully using e-marketplaces for a notable period of time. Accordingly, factors that contributed to the successful use of e-marketplaces informed the proposed model of this research. The model proposes that perceived trustworthiness of enterprises in e-marketplaces can be achieved through following the uncertainty reduction stages (Entry, Personal and Exit) and applying uncertainty reduction strategies (passive, active and interactive).
45

The essential oil from Cymbopogon validus

Naidoo, Nelisha January 2007 (has links)
Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xv, 136 leaves / The chemical and biological properties of the essential oil from Cymbopogon validus were investigated. Hydro-distillation was used to extract the oil from C. validus, the flower-heads, leaves, culms and rhizomes. The percentage oil yields obtained from the plant organs varied from 0.05 to 1.23%, with the greatest concentration found in the flower-heads and rhizomes, 1.23 and 1.12% respectively. A sensory evaluation of the oil revealed that the essential oil was slightly murky, pale yellow in colour, had a strong turpentine-like smell and remained liquid at room temperature. The oxidative stability of C. validus oil was evaluated by determining its Rancimat induction period (negative), peroxide value (60.56 meq/kg), iodine value (84.55), percentage free fatty acids (0.19%) and percentage cholesterol (3.03%). These results indicated that the oil was highly susceptible to oxidation. Chromatographic profiles of the oils from C. validus, as well as the plant organs were generated using gas chromatography-mass spectroscopy (GC-MS). Predominant compounds present in the oil included alpha-Cubebene, Camphene, Geraniol, Limonene, Myrcene, Palmitic acid and Sabinene. C. validus essential oil was also investigated for its antimicrobial (disk diffusion), antioxidant (1, 1-Diphenyl-1-Picrylhydrazyl (DPPH) assay), anti-inflammatory (5-lipoxygenase assay), anti-mosquito properties (insecticidal, larvicidal and repellency assays) and toxicity profile (Brine shrimp and Ames assays). The oil showed poor antimicrobial activity and inhibited the growth of only Gram positive bacteria with a minimum inhibitory concentration (MIC) of 0.0625 (vol/vol) for Bacillus, Micrococcus and Staphylococcus species. The oil also exhibited excellent antioxidant activity, scavenging more than 80% of DPPH free radicals and possesses anti-inflammatory activity (IC50=190 ppm). C. validus oil showed good adulticidal activity (53.7% mortality) and excellent larvicidal (100% mortality) and repellent activity (100% repellency) against Anopheles arabiensis mosquitoes. At high concentrations, the oil was toxic to brine shrimp larvae. However, when diluted it was safe and the minimum inhibitory concentration was 0.0001(vol/vol). The absence of revertant colonies at all essential oil concentrations in the Ames test suggest that the oil is not mutagenic. These results lead the way for exploiting C. validus oil as a multi-functional agent that has antibacterial, anti-oxidant, anti-inflammatory, and anti-mosquito properties.
46

Nutrição mineral e produção de óleo essencial em plantações de corymbia citriodora fertilizado com composto orgânico de lodo de esgoto /

Piazon Neto, Mario, 1985. January 2017 (has links)
Orientador: Iraê Amaral Guerrini / Banca: Fernando Carvalho Oliveira / Banca: José Leonardo de Moraes Gonçalves / Resumo: O lodo de esgoto está se tornando cada vez mais um grande problema para as cidades, pois com o aumento populacional há proporcionalmente um aumento desse resíduo. Uma alternativa para a sua disposição é a utilização no setor agrícola e florestal, com uma maior aptidão para o último, pois seu produto final não se destina a alimentação humana ou animal. Visto isso, pretende-se saber se o lodo de esgoto tratado (Biossólido) tem a capacidade de fornecimento nutricional adequado para a cultura de Corymbia citriodora (Hook.), espécie de múltiplos usos, onde se destaca a extração de óleo essencial. Este trabalho teve por objetivo comparar a fertilização de florestas homogêneas da espécie Corymbia citriodora, destinadas à produção de óleo essencial, com biossólido, através dos seguintes tratamentos: 0; 2,5; 5,0; 10; 15 e 20 Mg ha-1 de biossólido complementado com potássio e boro, fertilização química usual, um tratamento apenas com potássio e boro e testemunha absoluta. Antes da instalação do experimento em campo, realizou-se análise química do solo como base para as recomendações da adubação química. Parâmetros biométricos e nutricionais foram avaliados a cada três meses durante um ano, como altura, diâmetro de copa, índice de cor verde nas folhas e análise foliar, além de realizar a cada seis meses a análise do solo. Ao fim de 12 meses, coletou-se as folhas do terço médio e inferior da árvore para a quantificação da biomassa. Além disso, foram retiradas amostras ... / Abstract: The sewage sludge is becoming an increasingly big problem for cities, with the population growing; there is an increased proportion of this material. An alternative for disposal this waste is the use in agriculture and forestry, with a special ability of the latter, since the end product is not intended for human or animal feeding. Based on this, is to find out if the treated sewage sludge (biosolids) has the ability to supply adequate nutrition for the cultivation of Corymbia citriodora (Hook.), a species of multiple uses, which highlights the essential oil extraction.This study aims to compare the fertilizing forests homogeneous species Corymbia citriodora for the production of essential oil with biosolids (2.5, 5.0, 10 and 20 ton / ha K), usual chemical fertilizer, only one treatment with potassium and an absolute control without any fertilization. Before the experiment be deployed under field conditions, there will be a soil test recommendations as a basis for mineral fertilizers. Several parameters will be evaluated every three months during one year, which will be the following: height, crown diameter, level of chlorophyll in leaves and leaf analysis and every six months will be done soil and leaf analysis. At the time of leaves collect, dry weight will be measured in addition to the oil yield and quality, quantifying the content of citronelal by the method of chromatography. There were statistical differences for height, crown diameter and index of green, and for crown diameter indicated differences from the first evaluation (after three months). For nutrition, chemical analysis of leaves was ... / Mestre
47

Níveis de fósforo no desenvolvimento e produção de óleo essencial de Mentha piperita L. cultivada em solução nutritiva /

David, Evelize de Fátima Saraiva, 1970- January 2004 (has links)
Orientador: Carmen Silvia Fernandes Boaro / Banca: José Antonio Proença V. Moraes / Banca: Marcia Ortiz Mayo Marques / Resumo: Para o estudo do desenvolvimento da Mentha piperita L. e da produção de seu óleo essencial, foram cultivadas plantas em solução nutritiva com diferentes níveis de fósforo, que constituíram diferentes tratamentos, aos quais as plantas foram submetidas. Para tanto, as plantas foram cultivadas em solução nutritiva no 2 Hoagland & Arnon (1950), na mesma solução com decréscimo de 50% e com acréscimo de 50% de fósforo. As variáveis número de folhas, comprimento de parte aérea, massa seca dos diferentes órgãos, área foliar, razão de área foliar, área foliar específica, taxa assimilatória liquida, taxa de crescimento relativo, razão de massa foliar, distribuição de massa seca, rendimento e composição de óleo essencial foram avaliadas. O delineamento experimental foi inteiramente casualizado, com três níveis de fósforo, cinco colheitas e quatro repetições, em esquema fatorial 3x5. Para a análise do óleo essencial o delineamento foi inteiramente casualizado em esquema fatorial 3x3. Os resultados foram submetidos à análise de variância e as médias foram comparadas pelo teste Tukey, com 5% de significância. O fator colheita foi avaliado por análise de regressão, exceto na avaliação da produção e composição do óleo essencial. As plantas submetidas ao maior nível de fósforo e igual a 91,5/183,0 mg L-1 apresentaram tendência de aumento do número de lâminas foliares, área foliar, massa seca de lâminas foliares, massa seca total e dos teores de mentona. As plantas submetidas ao nível intermediário de fósforo, igual a 57,5/115,0 mg L-1 apresentaram maior massa seca de caule mais pecíolos e maior teor de mentofurano. Quando as plantas foram submetidas ao menor nível de fósforo, igual a 28,7/57,5 mg L-1, foi maior a massa seca de raízes, massa seca de estolões, produção de óleo essencial e teores de mentol, acetato de mentila e pulegona... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: To study the development of Mentha piperita L. and the production of essential oil plants were cultivated in nutritive solution under several levels of P. Original Hoagland & Arnon (1950) no 2 nutritive solution were one of the treatments, and the other experimental levels were this nutritive solution with 50% of the original P concentration, and added with 50% P over the original concentration. The variables evaluated were number of leaves, steam length, dry mass several organs, leaf area, leaf area ratio, specific leaf area, net assimilatory rate, relative growth rate, leaf mass ratio, dry mass distribution. Essential oil yield and composition were also assessed. A randomized factorial design 3x5 were used, with there levels of phosphorus. for essential oil, a randomized 3x3 factorial design were used. Data analysis consisted in application of ANOVA followed by the Tukey test, using the level of significance of 5%. The crop factor was studied using regression analysis, except for essential oil yield and composition. Highest P levels, 91,5/183,0 mg L-1 resulted on significantly higher values for number of leaves, leaf area, leaf dry mass, total dry mass and content menthone. Plants cultivated under intermediate P levels, 57,5/115,0 mg L-1 had higher values for stem plus petiole dry mass, and content menthofuram. When submitted to the lower level of P, 28,7/57,5 mg L-1, root dry mass, steam dry mass, menthol, essential oil yield, menthyl acetate and pulegone content were highest. Physiological indexes as leaf area ratio, leaf mass ratio, dry mass distribution of plants cultivated under the intermediate P levels were higher than those found in the P level of 91,5/183 mg L-1. We concluded that the best period to crop this plant, aiming for a highest yield of essential oil, was 60 days after transplantation... (Complete abstract click electronic access below) / Mestre
48

Essential oil treatment of VTC wood

Scouse, Adam A. 13 September 2012 (has links)
Western juniper and cinnamon essential oils were combined with ethanol at 2.5, 5, and 10% concentrations by weight and applied to hybrid poplar (Populus trichocarpa x P. deltoids) veneers by vacuum soaking to produce a naturally durable wood veneer with increased mechanical properties for use in structural composites. Half of these veneers were then modified using viscoelastic thermal compression to increase veneer density and modulus of elasticity. Following densification, unprocessed and VTC processed veneers receiving an essential oil treatment were subjected to an AWPA E21-06 Formosan termite exposure test, AWPA E24-06 mold box test, and brown rot (Gloeophyllum trabeum) decay bending test. While VTC processing drastically reduced the abundance of chemical components inherent within essential oil treatments, veneer specimens without VTC processing showed increased durability. A 10% juniper oil treatment drastically reduced Formosan termite attack on hybrid poplar veneers while a 10% cinnamon oil treatment significantly reduced mold growth. Timbor��, an industrial powdered borate treatment, withstood VTC processing and inhibited Formosan termite attack and mold growth. Tests to evaluate the effectiveness of essential oil treatments against brown rot were unsuccessful. Results suggest that incorporating a disodium octaborate tetrahydrate (DOT) treatment prior to VTC processing could help improve VTC wood durability. / Graduation date: 2013
49

Comprehensive two-dimensional supercritical fluid and gas chromatography (SFCxGC)

Venter, Andre. January 2003 (has links)
Thesis (Ph. D.)(Chemistry)--University of Pretoria, 2003. / Includes bibliographical references.
50

The essential oil from Cymbopogon validus

Naidoo, Nelisha January 2007 (has links)
Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xv, 136 leaves / The chemical and biological properties of the essential oil from Cymbopogon validus were investigated. Hydro-distillation was used to extract the oil from C. validus, the flower-heads, leaves, culms and rhizomes. The percentage oil yields obtained from the plant organs varied from 0.05 to 1.23%, with the greatest concentration found in the flower-heads and rhizomes, 1.23 and 1.12% respectively. A sensory evaluation of the oil revealed that the essential oil was slightly murky, pale yellow in colour, had a strong turpentine-like smell and remained liquid at room temperature. The oxidative stability of C. validus oil was evaluated by determining its Rancimat induction period (negative), peroxide value (60.56 meq/kg), iodine value (84.55), percentage free fatty acids (0.19%) and percentage cholesterol (3.03%). These results indicated that the oil was highly susceptible to oxidation. Chromatographic profiles of the oils from C. validus, as well as the plant organs were generated using gas chromatography-mass spectroscopy (GC-MS). Predominant compounds present in the oil included alpha-Cubebene, Camphene, Geraniol, Limonene, Myrcene, Palmitic acid and Sabinene. C. validus essential oil was also investigated for its antimicrobial (disk diffusion), antioxidant (1, 1-Diphenyl-1-Picrylhydrazyl (DPPH) assay), anti-inflammatory (5-lipoxygenase assay), anti-mosquito properties (insecticidal, larvicidal and repellency assays) and toxicity profile (Brine shrimp and Ames assays). The oil showed poor antimicrobial activity and inhibited the growth of only Gram positive bacteria with a minimum inhibitory concentration (MIC) of 0.0625 (vol/vol) for Bacillus, Micrococcus and Staphylococcus species. The oil also exhibited excellent antioxidant activity, scavenging more than 80% of DPPH free radicals and possesses anti-inflammatory activity (IC50=190 ppm). C. validus oil showed good adulticidal activity (53.7% mortality) and excellent larvicidal (100% mortality) and repellent activity (100% repellency) against Anopheles arabiensis mosquitoes. At high concentrations, the oil was toxic to brine shrimp larvae. However, when diluted it was safe and the minimum inhibitory concentration was 0.0001(vol/vol). The absence of revertant colonies at all essential oil concentrations in the Ames test suggest that the oil is not mutagenic. These results lead the way for exploiting C. validus oil as a multi-functional agent that has antibacterial, anti-oxidant, anti-inflammatory, and anti-mosquito properties.

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