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Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 107-111). Also available via the Internet.

1 ABSTRACT Charles University in Prague Faculty of pharmacy in Hradec Králové Department of pharmacognosy Student: Kateřina Šandová Supervisor: PharmDr. Marie Kašparová, PhD. Title of diploma thesis: Plant tissue cultures as a potential source of phenylpropanoids II. This diploma thesis deals with the monitoring of jasmonic acid biotic elicitation impact on the production of podophyllotoxin in Juniperus virginiana suspension culture. The monitoring was carried out in two varieties of J. virginiana: var. 'Glauca' (7th and 19th passage) and var. 'Hetzii' (7th passage). The elicitation of the suspension culture was performed in 4 jasmonic acid concentrations: 0.005 mmol/l, 0.05 mmol/l, 0.5 mmol/l, 5 mmol/l. Samples were taken after 6, 24, 48 and 168 hours of elicitation. The best podophyllotoxin production increase was observed in the suspension culture of Juniperus virginiana var. 'Glauca' (7th passage). To achieve this result, the concentration of elicitor was 5 mmol/l and elicitor was applied for 168 hours. The podophyllotoxin production percentage was 0.067% and production increased by 179% over the control. Keywords: Juniperus virginiana, suspension cultures, podophyllotoxin, elicitation

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Student: Jiří Olšar Supervisor: doc. PharmDr. Tomáš Siatka, CSc. Title of diploma thesis: Podophyllotoxin in eastern red cedar (Juniperus virginiana) This thesis describes the optimisation of the extraction process for quantity determination of podophyllotoxin in the leaves of Juniperus virginiana L. This determination was conducted through three different methods: the extraction in ultrasound bath, the extraction in the orbital shaker and the maceration in cold environment of 4 řC. Extractions were affected by various factors which were monitored, for instance time of extraction, temperature, and extraction solvents. The most efficient method appears to be the extraction in ultrasound bath with the use of methanol or a combination of phosphate buffer with ethyl-acetate.

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Experiments were conducted to study variation in the amount of podophyllotoxin in J. virginiana across nine –physiographic regions of Mississippi. The aim was bioprospection of podophyllotoxin from J. virginiana across Mississippi. Experiments were also conducted to utilize biproducts (i.e. needles) as a source of podophyllotoxin and essential oil. Dual extraction of both from the same plant material was obtained in order to develop economic protocol for industrial utilization. Three different experiments were conducted for the bioprospection and byproduct utilization of J.virginana. Experiment I: Study of variation in the amount of podophyllotoxin across nine physiographic regions and the study of contributing factors for the variability. Experiment II: Explore different plant parts as source of podophyllotoxin Experiment III: Establish a dual extraction protocol for extraction of podophyllotoxin and essential oil from J. virginiana.

Podophyllotoxin, a naturally occurring lignan isolated from several species of Podophyllum, is used as a precursor to the clinical chemotherapeutic agents teniposide and etoposide. The biosynthesis of podophyllotoxin is not fully understood, but its optical activity, like that of most lignans, is suggestive of enzyme-mediated processes. It has been proposed that the formation of podophyllotoxin begins with stereo-controlled coupling of a hydroxy cinnamyl alcohol derivative and a substituted hydroxy Cinnamic acid, although no "coupling" enzyme has been isolated to date. Further biosynthetic modifications of the coupled compound could lead to matairesinol and/or yatein, which have been proposed as potential biological precursors of podophyllotoxin. Although no firm evidence has been obtained to date, conversion of matairesinol to yatein has been postulated. This conversion would, however, involve biosynthetic steps which, though common for hydroxycinnamates, are unprecedented at the dimeric level. Conversion of yatein to podophyllotoxin has been demonstrated, with the conversion involving a stereo-controlled cyclization and subsequent stereospecific hydroxylation. In order to investigate the biosynthesis of podophyllotoxin, leading from the postulated precursors matairesinol and yatein, a series of stereospecific deuterium-labelled matairesinol and yatein derivatives was proposed and the synthetic methodology for each compound developed. The methodology used to obtain deuterium-labelled compounds can be extended to generating tritium-labelled compounds as well. With sufficient quantities of a number of the deuterium-labelled compounds, feeding studies can now be carried out in Podophyllum plants. Isolation and analysis of podophyllotoxin, from plants fed with labelled yatein, will allow determination of the stereochemical nature of yatein cyclization. Isolation and analysis of yatein, from plants fed with labelled matairesinol, will indicate whether matairesinol is indeed a precursor to yatein (and, hence, podophyllotoxin). The information obtained from the synthesis and incorporation of such labelled compounds should then provide a clearer understanding of some interesting but, as yet, unestablished biotransformations. / Master of Science

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Student: Lenka Srbová Supervisor: PharmDr. Marie Kašparová, Ph.D. Title of diploma thesis: Tissue culture of Juniperus virginiana L. as a promising source of podophyllotoxin. The diploma thesis deals with the cultivation of Juniperus virginiana tissue cultures. A growth was observed at Juniperus virginiana two years old culture (variety 'Glauca' and 'Grey Owl') after adding various concentrations of phenylalanine (1 mmol.l-1, 10 mmol.l-1 and 100 mmol.l-1 ) at selected time intervals. The results show that the highest increase in callus fresh weight was detected at Juniperus virginiana variety 'Grey Owl', particularly on the 14th day after adding 10 mmol.l-1 phenylalanine. Suspension culture was successfully derived from the Juniperus virginiana two years old callus culture (variety 'Glauca').