Master of Science / Department of Biology / David C. Hartnett / Invasive plants pose a global threat by changing natural communities and ecosystems in ways that may be irreversible. Marrubium vulgare L. (horehound), native to Eurasia, is an invasive exotic plant found throughout the United States. Little is known about M. vulgare in the U.S. and this study aimed to understand the basic biology, habitat, and population dynamics of M. vulgare in its invasive habitat as well as the role of disturbance in the invasions. Wind Cave National Park (WCNP), an area comprising ponderosa pine and mixed grass prairie vegetation types, was used as the site for this study. In a GPS and GIS mapping study, M. vulgare was found to be significantly associated with prairie dog towns, an Aristida purpurea - Dyssodia papposa (threeawn and fetid marigold) vegetation community (a vegetation type found exclusively on prairie dog towns), and certain types of loamy soils. M. vulgare was rarely found off of prairie dog towns and then only in other disturbed areas such as bison trails or tree falls. Population studies showed M. vulgare populations were mostly stable or slightly decreasing in density (though not significantly) from 2010 to 2011; however, a few of the populations did increase dramatically in density from 2010 to 2011. M. vulgare populations existed in high densities (78.3-322.9 ramets/m2) and in low densities (0.1-2.2 genets/m2) throughout WCNP. Disturbances including prairie dog burrows, bison trails, prairie dog and bison presence, mowing, and percent cover of bare ground were measured in relation to population dynamics. While M. vulgare populations were disturbance dependent, there was no clear relationship between disturbances and population dynamics. Examination of M. vulgare life history traits found that while M. vulgare had relatively low biomass allocation to reproduction as compared to native perennial prairie species, M. vulgare produced an extremely high number of small seeds (estimated 1487/plant). Seedling establishment rates were also high. While not quantified, M. vulgare appears to be effectively dispersed through bison epizoochory. These results help to inform management of M. vulgare populations: minimizing disturbance, decreasing propagule supply, and minimizing dispersal may help to reduce M. vulgare invasions.

<p>U okviru ove disertacije ispitane su mogućnosti primene savremenih metoda za dobijanje tečnih ekstrakata (ultrazvučna ekstrakcija, mikrotalasna ekstrakcija i ekstrakcija subkritičnom vodom) i lipofilnih ekstrakata (ekstrakcija superkritičnim ugljendioksidom) bogatih polifenolima iz nadzemnog dela očajnice (Marrubium vulgare L.). Tečni ekstrakti su optimizovani primenom eksperimentalnog dizajna i metode odzivne povr&scaron;ine, i podvrgnuti su spray drying tehnici su&scaron;enja. Tečni i suvi ekstrakti su detaljno ispitani po pitanju hemijskog sastava i biolo&scaron;ke aktivnosti, antimikrobne i in vitro antihiperglikemijske aktivnosti.<br />Za svaku od navedenih ekstrakcionih tehnika ispitan je uticaj glavnih parametara: ultrazvučna ekstrakcija (temperatura, vreme ekstrakcije i snaga ultrazvuka), mikrotalasna ekstrakcija (koncentracija etanola, vreme ekstrakcije i snaga mikrotalasa) i ekstrakcija subkritičnom vodom (temperatura, vreme ekstrakcije i koncentracija HCl u ekstragensu). Kod tečnih ekstrakata dobijenih ultrazvučnom i mikrotalasnom ekstrakcijom na optimizovanim uslovima utvrđeno je prisustvo hlorogenske kiseline i kvercetina koji nisu detektovani u maceratima. Ispitana je antimikrobna aktivnost oba ekstrakta i utvrđeno da je B. cereus najosetljiviji bakterijski soj, dok je u slučaju kvasaca S. cerevisiae posebno osetljiv na oba ekstrakta. Pored ove aktivnosti ispitana je i in vitro antihiperglikemijska aktivnost oba ekstrakta prema &alpha;-amilazi i &alpha;-glukozidazi, pri čemu ultrazvučni ekstrakt pokazuje veću antihiperglikemijsku aktivnost (50,63% inhibira &alpha;-amilazu i 48,67% inhibira &alpha;-glukozidazu) &scaron;to se potencijalno može objasniti prisustvom hlorogenske kiseline (33,11 &mu;g/mL) i kvercetina (34,88 &mu;g/mL). U subkritičnom ekstraktu, dobijenom na optimalnim uslovima, detektovano je jedino prisustvo hidroksi metilfurfurala usled čega ovaj ekstrakt nije podvrgnut ispitivanju antimikrobne i antihiperglikemijske aktivnosti.<br />U cilju ekstrakcije lipofilnih komponenata M. vulgare primenjene su destilacija etarskog ulja (0,05%), Soxhlet ekstrakcija (3,23%) i ekstrakcija superkritičnim ugljendioksidom na pritiscima 100, 200 i 300 bar i temperaturama 40, 50 i 60 &deg;C. Najdominantnija komponenta u svim dobijenim superkritičnim ekstraktima je hemotaksonomski marker marubiin koji nije identifikovan u Soxhlet ekstraktu.<br />Tečni ekstrakti dobijeni ultrazvučnom i mikrotalasnom ekstrakcijom na optimizovanim uslovima i macerat su osu&scaron;eni spray drying tehnikom (uz dodatak 10 i 50% maltodekstrina) u cilju dobijanja stabilnije forme suvog ekstrakta. Suvim ekstraktima su određene najznačajnije fizičke osobine i hemijski sastav kao i antimikrobna i antihiperglikemijska aktivnost kako bi se procenila mogućnost njihove inkorporacije u funkcionalnu hranu, dijetetske suplemente ili u formulaciji različitih gotovih proizvoda koji se primenjuju preventivno ili radi pobolj&scaron;anja zdravlja ljudi.</p> / <p>Within the scope of this dissertation, the possibilities of applying modern methods for obtaining liquid (ultrasonic extraction, microwave extraction and subcritical water extraction) and lipophilic extracts (extraction with supercritical carbon dioxide) rich in polyphenols from the aboveground part of white horehound (Marrubium vulgare L.) were examined. Liquid extracts were optimized using an experimental design and response surface method, and subjected to spray drying. Liquid and dry extracts have been extensively examined for their chemical composition and biological activity, antimicrobial and in vitro antihyperglycaemic activities.<br />For each of these extraction techniques, the influence of the main parameters was examined: ultrasonic extraction (temperature, extraction time and ultrasound power), microwave extraction (ethanol concentration, extraction time and microwave power) and subcritical water extraction (temperature, extraction time and HCl concentration in the extractant). Liquid extracts obtained by ultrasonic and microwave extraction under optimized conditions revealed the presence of chlorogenic acid and quercetin, which were not detected in macerates. The antimicrobial activity of both extracts was examined and B. cereus was found to be the most sensitive bacterial strain, whereas in the case of yeast S. cerevisiae was particularly sensitive to both extracts. In addition to this activity, the in vitro antihyperglycaemic activities of both extracts against &alpha;-amylase and &alpha;-glucosidase were investigated, with ultrasound extract showing higher antihyperglycemic activity (50.63% inhibited &alpha;-amylase and 48.67% inhibited &alpha;-glucosidase) which could potentially be explained by the presence of chlorogenic acid (33.11 &mu;g/mL) and quercetin (34.88 &mu;g/mL). In the subcritical extract, obtained under optimal conditions, only the presence of hydroxy methylfurfural was detected, and this extract was not subjected to antimicrobial and antihyperglycemic activity.<br />For the extraction of lipophilic components of M. vulgare, distillation of essential oil (0.05%), Soxhlet extraction (3.23%) and extraction with supercritical carbon dioxide at pressures of 100, 200 and 300 bar and at temperatures of 40, 50 and 60 &deg; C were applied. The most dominant component in all the supercritical extracts obtained is the chemotaxonomic marker marubiin, which was not identified in the Soxhlet extract.<br />The liquid extracts obtained by the ultrasound and microwave extraction under optimized conditions and the macerate were spray dried (with the addition of 10 and 50% maltodextrin) to obtain a more stable form of the dry extract. Dry extracts underwent determination of the most important physical properties and chemical composition as well as antimicrobial and antihyperglycemic activities to evaluate their incorporation into functional foods, dietary supplements or in the formulation of various finished dosage forms that are administered preventively or to improve human health.</p>