Artemisinin is produced in the leaves of Artemisia annua and is currently one of the most valuable antimalarial treatments. A. annua is of Asian origin but many other family members have been identified worldwide. A. annua however, is the only one that produces artemisinin. Synthetic production of artemisinin is not yet feasible, not to mention very expensive and the product yields are relatively low. The aims of this study were threefold: 1) To regenerate callus, cell cultures and plants from genetically modified root cultures of A. afra into which an artemisinin biosynthetic gene was inserted from A. annua 2) To investigate the probability that fungal endophytes are responsible for the production of artemisinin and 3) To establish two fields of high yielding varieties of A. annua plants and evaluate whether artemisinin production of these two locations will remain high. Callus and cell cultures of the genetically modified A. afra root cultures were established, but no shoots have been produced as of yet and this is an on-going investigation. Fungal endophytes were sampled and none of the endophytes produced artemisinin. Five different lines of A. annua were cultivated, successfully grown and harvested. Measurements were taken at different stages of processing, these were compared and analysed using various methods such as height and mass comparisons. Comparisons revealed that the production of artemisinin is correlated to local sets of conditions rather than the variety of individual lines. The genetic potential to produce high quantities of artemisinin appears to have been lost, instead of being maintained. We confirmed that secondary compound production and specifically, artemisinin, is enhanced by certain stress factors on the plants. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Plant Science / unrestricted

Several studies were conducted with Artemisia vulgaris (mugwort). The first study involved the observation of shoot initiation from various length rhizome sections arxi positions. A second study was conducted to observe growth habits of mugwort and to determine the amount of infestation and production in a growing season. The third study was conducted to determine fenac rates that would prevent shoot growth from mugwort rhizomes. Also, various herbicides were evaluated in field experiments for the control of mugwort. The last study involved the effects of fenac on respiration and some respiratory enzymes. The most unifonn plants were observed from two-inch rhizome sections. There was no difference in bud viability of older or younger areas of rhizomes. New rhizome production became rapid about seven weeks after small muqwort plants were transplanted to the field. There was a continuous increase in shoots and rhizomes throughout the growing period. New plants were initiated in the spring of the next year from rhizomes that had overwintered in the soil. Fenac, when mixed with soil at two ppn or above, prevented shoot initiation from rhizome buds. When fenac was present in nutrient solution at rates above two ppm, no shoot growth was observed. In the field control experiments, fenac, dicamba, and Tordon tended to give the best control of mugwort. There tended to be an increase in the enzymatic activity of mugwort after the plants were sprayed with fenac. / Master of Science

Artemisia annua L. is a common type of wormwood that grows throughout the world. Artemisinin, a terpene compound in A. annua, has recently been recognized as the most promising antimalaria drug. Artemisinin and other types of terpenoids are synthesized and accumulated in glandualr trichomes that appear on the surface of leaf, stem and flower bud. To identify new genes involved in artemisinin biosynthesis and trichome function in A. annua, a normalized glandular trichome cDNA collection was sequenced by Roche GS FLX pyrosequencing system. Two sequencing runs generated totally 85M nucleotides which were further assembled into 190,377 unigenes (42,678 contigs and 147,699 sigletons). Putative functions were assigned to the unigenes based on Blast search against GeneBank database. Many terpene biosynthesis pathway genes were identified from the pyrosequencing ESTs. Together with other identified A. annua terpene pathway genes, a global view of terpene biosynthesis in glandular trichomes of A. annua were re-established. Meanwhile, a WD repeat protein, AaWD40, which show high amino acid sequence similarity with its Arabidopsis ortholog, AtTTG1 (AT5G24520) was identified. To investigate the functional relevance of AaWD40 to its Arabidopsis counterpart, genetic complementation test using Arabidopsis mutants was conducted. When AaWD40 was transformed into Arabidopsis transparent testa glabrous1 (ttg1-1) mutant, the anthocyanins and proanthocyanidin (PAs) production in seeds were restored, and the trichomeless phenotype of ttg1-1 mutant was rescued. In addition, over-expression of AaWD40 and AtTTG1 modulated the expression of WUS and CLVs genes which are required to maintain the stem-cell niche of Arabidopsis shoot apex. Transcriptomic profiling of transgenic Arabidopsis over-expressing AaWD40, TTG1, or ttg1-1 mutant revealed lists of genes modulated by these two WD40 genes homologue and gene ontology (GO) analysis suggested that the top-ranked categories are defense, stress response and developmental programme. We hypothesize that WD40 repeat protein act as a crucial regulatory factor in a wide variety of cellular functions in A. thaliana. / Wang, Wei. / Advisers: Guo Dianjing; Jiang Liwen. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 82-105). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Malaria är en farlig tropiksjukdom orsakad av parasiten Plasmodium som vållar många dödsfall varje år. Sedan några år tillbaka rekommenderar Världshälsoorganisationen (WHO) användandet av artemisinin och dess derivat för behandlandet av malaria. Artemisinin syntetiseras normalt i växten Artemisia annua i lågt utbyte. På grund av det låga utbytet är läkemedlet väldigt dyrt. Då parasiten blivit resistent mot de flesta malarialäkemedel är artemisinin ett viktigt preparat i kampen mot malaria. Forskning pågår för att hitta nya eller effektivare metoder för framställning av substansen då en oro finns att produktionen från A. annua inte kommer kunna möta kraven från läkemedelsindustrin. En av teorierna är ifall andra växter inom Artemisia-släktet kan syntetisera artemisinin då flera växter uppvisat helande effekter vid andra sjukdomar. I denna studie undersöktes det ifall växterna A. vulgaris och A. absinthium från Artemisia-släktet skulle kunna syntetisera artemisinin. Med hjälp av molekylärbiologiska tekniker isolerades genetiskt material ifrån växterna. Materialet granskades efter ribonukleinsyra (RNA)- och deoxiribonukleinsyra (DNA) -sekvenser för funktionella enzym som katalyserar reaktioner i artemisinins biosyntes. Ifall generna uttrycks för dessa enzym kan eventuellt artemisinin bildas. Växterna hämtades från Revsudden, Sverige och genetiskt material isolerades. Förekomsten av genuttryck för fem viktiga enzym i artemisinins biosyntes undersöktes med Polymerase Chain Reaction (PCR). Resultatet blev att växterna hade genuttryck för två respektive tre av de fem enzymen. Detta pekar mot att varken A. vulgaris eller A. absinthium kan syntetisera artemisinin då de saknade några viktiga nyckelenzym i syntesen. Trots att en tidigare studie indikerar närvaro av artemisinin i dessa växter kan slutsatsen dras att A. vulgaris och A. absinthium inte kan bilda artemisinin. / Malaria is a tropical disease that accounts for the death of many people annually and is caused by a parasite called Plasmodium. The World Health Organization (WHO) recommends artemisinin and its derivates for malaria treatment. Artemisinin is synthesized generally in Artemisia annua in small amounts. The artemisinin-treatment is very expensive due to the small amounts produced in the plant. Since the parasite has developed resistance towards many antimalarial drugs, artemisinin is an important drug against malaria. Research to find alternative methods for artemisinin-production has begun because there is a great concern that artemisinin-production at current rate will not meet the demand from the pharmaceutical industry. Some speculate if artemisinin can be synthesized in other plants from the Artemisia-genus since many plants have shown healing properties towards other diseases. In this study, we investigated if A. vulgaris and A. absinthium could produce artemisinin. Using molecular biology techniques, genetic material was isolated from the plants. Ribonucleotide (RNA)- and deoxyribonucleotide (DNA)- sequences which encode important enzymes in the artemisinin biosynthesis were examined. In case all the genes were expressed, artemisinin may be synthesized. The plants were picked on Revsudden, Sweden and genetic material was isolated. The presence of gene expression of five important enzymes in the artemisinin biosynthesis was investigated by Polymerase Chain Reaction (PCR). The results showed that the plants had gene expression of two respectively three of the five enzymes. Due to the fact that the plants need all five enzymes to synthesize artemisinin, even though a recent study has shown presence of artemisinin in these plants, this study concludes that artemisinin cannot be synthesized in A. vulgaris and A. absinthium.

Made available in DSpace on 2014-06-11T19:24:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-25Bitstream added on 2014-06-13T19:11:19Z : No. of bitstreams: 1 cervezan_tcm_me_botfca.pdf: 497237 bytes, checksum: d6694ebd7c9403db49840bbd8579a450 (MD5) / A espécie Artemisia annua, Asteraceae, nativa da China, tem a artemisinina como seu principal componente ativo, é considerado um potente antimalárico. Com o aumento do valor dos princípios ativos naturais, estudos relacionados à pós-colheita e armazenamento de material vegetal tornam-se importantes para melhor conservação de suas propriedades fitoterápicas. O presente estudo teve como objetivo definir as melhores condições de armazenamento para preservar a qualidade da droga vegetal. Folhas de A. annua secas foram armazenadas por seis meses em sacos de polietileno envolto por papel Kraft e acondicionadas em quatro tratamentos: em condição ambiente e refrigerada a 4º±2C, em embalagem normal e em embalagem sob vácuo. No tempo zero e nos períodos de 30, 90, 120 e 180 dias foram realizados as análises microbiológicas e avaliação do teor de artemisinina. Os resultados dos ensaios microbiológicos não demonstraram contaminação significante, assim como o teor de umidade do material armazenado, que permanecem entre 5% a 10%, mantendo-se dentro do parâmetro aceitável. O tratamento sem vácuo ambiente (SVA) foi o que melhor manteve estabilidade de armazenamento durante os 180 dias, no entanto, foi o sem vácuo refrigerado (SVR) que apresentou maior eficiência para a conservação do teor de artemisinina / Artemisia annua is an Asteracea native to China, its principal active component, artemisinin, is considered a potent antimalarial drug. With the increased interest in natural active principles, studies related to post-harvest and storage of vegetable material become important for better conservation of its phytotherapic properties. Therefore, the present study had as objective define best storage conditions to preserve and keep the quality of phytotherapic Leaves of A. annua dried were stored for six months in polyethylene bags wrapped in Kraft paper and packed in four treatments: at ambient condition, at ambient condition with vacuum packing in refrigerated conditions at 4° ± 2C normal and vacuum packing. At time zero, and the periods of 30, 90, 120 and 180 days were performed microbiological analyzes and evaluation of the level of artemisinin. The results of microbiological tests showed no significant contamination, as well as the moisture content of stored (biological) material, which remain between 5% and 10%, keeping within acceptable parameters. The vacuum environment without treatment (SVA) was the best storage stability maintained during 180 days, however, no vacuum was refrigerated (SVR) showed that greater efficiency to conserve the content of artemisinin, compared to the others

La presente tesi di dottorato ha come obiettivo centrale quello di comprendere come la pittrice Artemisia Gentileschi (1593-1654) si è inserita ed ha svolto il suo lavoro in alcune delle città europee dove c’erano più finanziamenti per le arti plastiche, come Roma, Firenze, Venezia, Napoli, e Londra nella prima metà del XVII secolo, e quello di analizzare le varie costruzioni di sé e le rappresentazioni del femminile nelle sue corrispondenze epistolari e nella sua opera pittorica. A questo fine, saranno utilizzate fonti scritte, che ci permettono di indagare sulla traiettoria di vita di Artemisia, sul suo lavoro come pittrice in diverse aree della penisola italiana e dell’Europa; e fonti visuali, che mostrano la dimensione della sua opera pittorica in generi diversi, come per esempio i temi della tradizione veterotestamentaria, storici, mitologici, ritratti, autoritratti. Le fonti rivelano la permanenza di Artemisia in diversi spazi di consumo delle immagini, in ritagli di regno, vice regni, ducati, repubbliche, così come in luoghi gestiti da figure ecclesiastiche e tra rilevanti collezionisti privati con i quali negoziò. In questo senso, l’utilizzo dei concetti di rappresentazione e di genere furono cardinali per la tesi e contribuirono ad evidenziare il dialogo della pittrice con la cultura dell’epoca ed il suo lascito nella storia dell’arte/pittura, così come i conflitti messi in moto dall’artista di fronte alle questioni di genere vigenti al tempo. / A presente tese de doutorado tem como objetivo central entender como a pintora Artemisia Gentileschi (1593-1654) se inseriu e atuou em algumas das cidades europeias em que mais havia o financiamento das artes plásticas, como Roma, Florença, Veneza, Nápoles e Londres, na primeira metade do século XVII; e analisar as construções de si e representações do feminino em suas correspondências e em sua obra pictórica. Para tal, utilizamos fontes escritas, que nos permitiram problematizar a trajetória de vida de Artemisia, assim como sua atuação como pintora em diferentes regiões da península italiana e da Europa; e fontes visuais, que dão a ver a dimensão de sua obra em diferentes gêneros, a exemplo dos temas da tradição veterotestamentária, históricos, mitológicos, retratos e autorretratos. As fontes revelam a permanência de Artemisia em diferentes espaços de consumo de imagens, em cortes de reinos, vice-reinos, ducados e repúblicas, bem como nos lugares administrados por figuras do clero e entre relevantes colecionadores particulares com os quais negociou. Nesse sentido, os usos dos conceitos de representação e gênero foram norteadores para a tese e contribuíram para evidenciar os diálogos da pintora com a cultura de sua época e seu legado para a história da arte/pintura, bem como os embates travados pela artista frente às questões de gênero vigentes em seu tempo. / The main objective of this doctoral thesis is to understand how the painter Artemisia Gentileschi (1593-1654), in the first half of the 17th century, was inserted and acted in some of the European cities where there was more financing of plastic arts, such as Rome, Florence, Venice, Naples and London; and analyze the constructions of self and representations of the feminine in her correspondence and pictorial work. For that, we used written sources, which allowed us to problematize the life trajectory of Artemisia, her work as a painter in different regions of the Italian peninsula and Europe; and visual sources, which make it possible to visualize the dimension of her pictorial work in different genres, such as the themes of the Old Testament tradition, historical, mythological, portraits and self-portraits. The sources reveal the permanence of Artemisia in different spaces of consumption of images, courts of kingdoms, viceroys, duchies, republics, as well as in the places administered by figures of the clergy and among the relevant private collectors with whom she negotiated. In this sense, the uses of the concepts of representation and gender were guiding the thesis and contributed to highlight the dialogues of the painter with the culture of her time and her legacy to the history of art / painting, as well as the clashes waged by the artist regarding the gender issues in force in her time.

La presente tesi di dottorato ha come obiettivo centrale quello di comprendere come la pittrice Artemisia Gentileschi (1593-1654) si è inserita ed ha svolto il suo lavoro in alcune delle città europee dove c’erano più finanziamenti per le arti plastiche, come Roma, Firenze, Venezia, Napoli, e Londra nella prima metà del XVII secolo, e quello di analizzare le varie costruzioni di sé e le rappresentazioni del femminile nelle sue corrispondenze epistolari e nella sua opera pittorica. A questo fine, saranno utilizzate fonti scritte, che ci permettono di indagare sulla traiettoria di vita di Artemisia, sul suo lavoro come pittrice in diverse aree della penisola italiana e dell’Europa; e fonti visuali, che mostrano la dimensione della sua opera pittorica in generi diversi, come per esempio i temi della tradizione veterotestamentaria, storici, mitologici, ritratti, autoritratti. Le fonti rivelano la permanenza di Artemisia in diversi spazi di consumo delle immagini, in ritagli di regno, vice regni, ducati, repubbliche, così come in luoghi gestiti da figure ecclesiastiche e tra rilevanti collezionisti privati con i quali negoziò. In questo senso, l’utilizzo dei concetti di rappresentazione e di genere furono cardinali per la tesi e contribuirono ad evidenziare il dialogo della pittrice con la cultura dell’epoca ed il suo lascito nella storia dell’arte/pittura, così come i conflitti messi in moto dall’artista di fronte alle questioni di genere vigenti al tempo. / A presente tese de doutorado tem como objetivo central entender como a pintora Artemisia Gentileschi (1593-1654) se inseriu e atuou em algumas das cidades europeias em que mais havia o financiamento das artes plásticas, como Roma, Florença, Veneza, Nápoles e Londres, na primeira metade do século XVII; e analisar as construções de si e representações do feminino em suas correspondências e em sua obra pictórica. Para tal, utilizamos fontes escritas, que nos permitiram problematizar a trajetória de vida de Artemisia, assim como sua atuação como pintora em diferentes regiões da península italiana e da Europa; e fontes visuais, que dão a ver a dimensão de sua obra em diferentes gêneros, a exemplo dos temas da tradição veterotestamentária, históricos, mitológicos, retratos e autorretratos. As fontes revelam a permanência de Artemisia em diferentes espaços de consumo de imagens, em cortes de reinos, vice-reinos, ducados e repúblicas, bem como nos lugares administrados por figuras do clero e entre relevantes colecionadores particulares com os quais negociou. Nesse sentido, os usos dos conceitos de representação e gênero foram norteadores para a tese e contribuíram para evidenciar os diálogos da pintora com a cultura de sua época e seu legado para a história da arte/pintura, bem como os embates travados pela artista frente às questões de gênero vigentes em seu tempo. / The main objective of this doctoral thesis is to understand how the painter Artemisia Gentileschi (1593-1654), in the first half of the 17th century, was inserted and acted in some of the European cities where there was more financing of plastic arts, such as Rome, Florence, Venice, Naples and London; and analyze the constructions of self and representations of the feminine in her correspondence and pictorial work. For that, we used written sources, which allowed us to problematize the life trajectory of Artemisia, her work as a painter in different regions of the Italian peninsula and Europe; and visual sources, which make it possible to visualize the dimension of her pictorial work in different genres, such as the themes of the Old Testament tradition, historical, mythological, portraits and self-portraits. The sources reveal the permanence of Artemisia in different spaces of consumption of images, courts of kingdoms, viceroys, duchies, republics, as well as in the places administered by figures of the clergy and among the relevant private collectors with whom she negotiated. In this sense, the uses of the concepts of representation and gender were guiding the thesis and contributed to highlight the dialogues of the painter with the culture of her time and her legacy to the history of art / painting, as well as the clashes waged by the artist regarding the gender issues in force in her time.

La presente tesi di dottorato ha come obiettivo centrale quello di comprendere come la pittrice Artemisia Gentileschi (1593-1654) si è inserita ed ha svolto il suo lavoro in alcune delle città europee dove c’erano più finanziamenti per le arti plastiche, come Roma, Firenze, Venezia, Napoli, e Londra nella prima metà del XVII secolo, e quello di analizzare le varie costruzioni di sé e le rappresentazioni del femminile nelle sue corrispondenze epistolari e nella sua opera pittorica. A questo fine, saranno utilizzate fonti scritte, che ci permettono di indagare sulla traiettoria di vita di Artemisia, sul suo lavoro come pittrice in diverse aree della penisola italiana e dell’Europa; e fonti visuali, che mostrano la dimensione della sua opera pittorica in generi diversi, come per esempio i temi della tradizione veterotestamentaria, storici, mitologici, ritratti, autoritratti. Le fonti rivelano la permanenza di Artemisia in diversi spazi di consumo delle immagini, in ritagli di regno, vice regni, ducati, repubbliche, così come in luoghi gestiti da figure ecclesiastiche e tra rilevanti collezionisti privati con i quali negoziò. In questo senso, l’utilizzo dei concetti di rappresentazione e di genere furono cardinali per la tesi e contribuirono ad evidenziare il dialogo della pittrice con la cultura dell’epoca ed il suo lascito nella storia dell’arte/pittura, così come i conflitti messi in moto dall’artista di fronte alle questioni di genere vigenti al tempo. / A presente tese de doutorado tem como objetivo central entender como a pintora Artemisia Gentileschi (1593-1654) se inseriu e atuou em algumas das cidades europeias em que mais havia o financiamento das artes plásticas, como Roma, Florença, Veneza, Nápoles e Londres, na primeira metade do século XVII; e analisar as construções de si e representações do feminino em suas correspondências e em sua obra pictórica. Para tal, utilizamos fontes escritas, que nos permitiram problematizar a trajetória de vida de Artemisia, assim como sua atuação como pintora em diferentes regiões da península italiana e da Europa; e fontes visuais, que dão a ver a dimensão de sua obra em diferentes gêneros, a exemplo dos temas da tradição veterotestamentária, históricos, mitológicos, retratos e autorretratos. As fontes revelam a permanência de Artemisia em diferentes espaços de consumo de imagens, em cortes de reinos, vice-reinos, ducados e repúblicas, bem como nos lugares administrados por figuras do clero e entre relevantes colecionadores particulares com os quais negociou. Nesse sentido, os usos dos conceitos de representação e gênero foram norteadores para a tese e contribuíram para evidenciar os diálogos da pintora com a cultura de sua época e seu legado para a história da arte/pintura, bem como os embates travados pela artista frente às questões de gênero vigentes em seu tempo. / The main objective of this doctoral thesis is to understand how the painter Artemisia Gentileschi (1593-1654), in the first half of the 17th century, was inserted and acted in some of the European cities where there was more financing of plastic arts, such as Rome, Florence, Venice, Naples and London; and analyze the constructions of self and representations of the feminine in her correspondence and pictorial work. For that, we used written sources, which allowed us to problematize the life trajectory of Artemisia, her work as a painter in different regions of the Italian peninsula and Europe; and visual sources, which make it possible to visualize the dimension of her pictorial work in different genres, such as the themes of the Old Testament tradition, historical, mythological, portraits and self-portraits. The sources reveal the permanence of Artemisia in different spaces of consumption of images, courts of kingdoms, viceroys, duchies, republics, as well as in the places administered by figures of the clergy and among the relevant private collectors with whom she negotiated. In this sense, the uses of the concepts of representation and gender were guiding the thesis and contributed to highlight the dialogues of the painter with the culture of her time and her legacy to the history of art / painting, as well as the clashes waged by the artist regarding the gender issues in force in her time.

Dissertation submitted in fulfilment for the requirements of the Degree of Master of Technology in Biomedical Technology, Durban University of Technology, 2012. / Introduction Medicinal plants have been used for centuries as remedies for human diseases because they contain components of therapeutic value. Recently, the acceptance of traditional medicine as an alternative form of health care and the development of microbial resistance to the available antibiotics have led scientists to investigate the antimicrobial activity of medicinal plants Aim The aim of this study was to investigate the antimicrobial activity of extracts obtained from medicinal plants used in traditional medicine. A comparative study was carried out on the antimicrobial properties of extracts obtained by two different methods in order to choose that which extracts the most effective antimicrobial compounds. Methodology The plants used in this study Artemisia afra, Erythrina lysistemon and Psidium guajava were harvested from the Silverglen Nature Reserve (Chatsworth) early in the morning (8 a.m.). The leaves of A. afra and P. guajava extracts and the bark of E. Lysistemon were used to prepare the extracts. All plant extracts were prepared according to modified method of the German Homeopathic Pharmacopoea. Two solvents, water and 60 percent ethanol were used to extract the antibacterial compounds from plant material. The extracts were then assessed for their antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The effect of the plant extracts on these bacteria was determined by the disk diffusion test, which was used as the screening test. Positive results were further subjected to the minimum inhibitory concentration and minimum bactericidal concentration assays. Tubes that showed no turbidity were then sub-cultured onto non-selective plates. Bacterial sensitivity testing was carried out in accordance with modified Kirby-Bauer Antimicrobial Sensitivity Test. An attempt was made to identify some antibacterial compounds using Thin Layer Chromatography and High Pressure Liquid Chromatography. Results None of the gram negative organisms were inhibited by Artemisia afra, Erythrina cafra and Psidium guajava. Only the ethanol extracts of all three plants were able to inhibit Staphylococcus aureus but not Escherichia coli and Pseudomonas auruginosa. None of the test organisms were inhibited by the aqueous extracts of all three plants used in this study. In the screening test, the zones of inhibition for ethanol extracts against Staphylococcus aureus ranged from 3mm – 7mm. The minimum inhibitory concentration ranged from 16.67 percent – 83.3 percent inhibition depending on the dilution of the extract. Quercetin and Catechin were identified as some of the antibacterial compounds present in the leaves of Psidium guajava. These two compounds were not identified on Erythrina lysistemon and Artemisia afra. Conclusion The results obtained in this study have proven that Artemisia afra, Erythrina cafra and Psidium guajava ethanol extracts contain antibacterial substances. The ethanol extracts of all plants in this study inhibited the growth of Staphylococcus aureus but had no effect on the gram negative bacteria. Aqueous plant did not inhibit the growth of any bacteria in this study. This study has also shown that antibacterial effect of these extracts may be considerably enhanced in traditional treatment if traditional healers can include ethanol as one of the extraction solvents. The results obtained in this study might be considered sufficient for further studies aimed at isolating and identifying the active compounds and evaluating possible synergism of antimicrobial activity among these extracts. Investigations on toxicity of these extracts should also be carried out.

The dichloromethane extracts (1 mg/ml) of Artemisia pacifica Nutt and Guardiola platyphylla Gray (fam. Asteraceae) separately demonstrated in vitro growth inhibition of Staphylococcus aureus (UA 9-29), Bacillus subtilis (UA 2-27), Klebsiella pneumoniae (UA 3-9) and Candida albicans (UA 97). Each of these extracts were subjected to bioassay-directed solvent extraction and partition in order to obtain concentrated active fractions. Subsequently, the active compounds were isolated and identified from these fractions. Artemisia pacifica Nutt. The active compound was the major component isolated from A. pacifica. By comparing the physical and chemical data with previously reported data, this compound was identified as dehydrofalcarindiol. Dehydrofalcarindiol demonstrated growth inhibition against S. aureus (50 μg/ml), B. subtilis (25 μg/ml), K. pneumoniae (100 μg/ml) and C. albicans (25 μg/ml). Its diacetyl derivative was devoid of activity at 100 μg/ml. Guardiola platyphylla Gray. The active fraction obtained from G. platyphylla contained unstable compounds that decomposed in the presence of air. Size exclusion chromatography (Sephadex LH-20) was used to fractionate the active fraction. Two new sesquiterpenes, the o-catechol derivatives (1S,4S) and (1S,4R)-7,8-dihydroxy-11,12-dehydrocalamenene, were eluted from the column as a mixture. The mixture of their diacetyl derivatives was oxidized with CrO₃ in AcOH. The major oxidation product was identified as (1S)-7,8-diacetyl-4-oxodeisopropylcalamenene, thereby verifying the sole difference to be the configuration at C-4. This sesquiterpene mixture completely inhibited the growth of S. aureus (100 μg/ml), B. subtilis (50 μg/ml), K. pneumoniae (100 μg/ml) and C. albicans (100 μg/ml). After removal of the sesquiterpenes from the active fraction, the remaining compounds displayed the same level of activity. Another six compounds were also isolated from this mixture as acetylated derivatives due to their instability. Their dimeric structures were identified by 2D-NMR techniques (COSY, HETCOR and NOESY). These dimers may be artifacts since they were formed from their o-quinone monomers when kept at room temperature for a week or when heated at 60°C for 4 hours.