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MSc (Med) (Pharmaceutical Affairs), Faculty of Health Sciences, University of the Witwatersrand / Fifteen traditional medicinal plants, indigenous to southern Africa, that are used to treat various respiratory ailments were screened for their antimicrobial activity and their chemical profiles were documented. Acetone:methanol (1:1) extracts were prepared from the leaves, stems, roots, barks and thorns of the investigated plant species. The antimicrobial activity was determined against pathogens associated with respiratory conditions i.e. Moraxella catarrhalis, Bacillus cereus, Enterococcus faecalis, Klebsiella pneumoniae, Staphylococcus aureus, Candida albicans and Cryptococcus neoformans. The MIC values ranged from 0.08 mg/ml to 12 mg/ml. The two pathogens against which the most number of extracts obtained MIC values that were ≤ 1 mg/ml were Moraxella catarrhalis (68% of the extracts) and Bacillus cereus (56% of the extracts). The plant extracts that obtained the five lowest average MIC values against the respiratory pathogens were the root extracts of Terminalia sericea (0.69 mg/ml), leaf and stem extract of Chenopodium ambrosioides (1.04 mg/ml), leaf, stem and flower extract of Leucas martinicensis (1.10 mg/ml), leaf extract of Zanthoxylum davyi (1.29 mg/ml) and the leaf and stem extracts of Lantana rugosa (1.32 mg/ml). For the bioautographic assays, clear zones of inhibition were recorded for Lantana rugosa (leaves and stems) and Vitex rehmannii (leaves) against Staphylococcus aureus and Moraxella catarrhalis. The root extract of Ziziphus mucronata had a clear zone of inhibition against Staphylococcus aureus. The leaf and stem extracts of Chenopodium ambrosioides had a clear zone of inhibition against Moraxella catarrhalis. The chemical profiles that were recorded for the plant extracts comprised of HPLC and TLC chromatograms. The HPLC and TLC profiles resulted in the separation of the chemical constituents thus providing a chemical fingerprint for the plant extracts. Flavonoids were tentatively identified for Acacia sieberiana (leaves), Alepidea amatymbica (roots), Clematis oweniae (leaves), Clerodendrum glabrum (leaves), Heteromorpha arborescens (bark), Peucedanum caffrum (roots B), Vitex rehmannii (leaves) and Ziziphus mucronata (leaves). The TLC chromatograms qualitatively displayed good separation of the compounds present in the plant extracts. The antimicrobial activity recorded for the plant extracts validates their traditional uses to treat various respiratory infections and the chemical profiles provide a reference of the chemical profiles of the plant extracts that can be used in future investigations

El principal objectiu d'aquest treball es avaluar els efectes d'un additiu comercial XT (5% carvacrol, 3% cinamaldehide, 2% oleoresina d capsicum) sobre els rendiments productius i diferents paràmetres de la fisiologia digestiva del garrí deslletat precoçment. Un altre objectiu d'aquest treball es avaluar les possibles interaccions del XT amb altres ingredients, nutrients i additius de la dieta. Aquest treball s'ha d'entendre com a part d'un ampli pla de recerca multicentric organitzat per la companyia Pancosma. En concret hem avaluat i) l'efecte del XT als paràmetres mencionats depenent del nivell i font de proteïna, ii) la possible interacció entre l'XT i l'àcid fòrmic, i la comparació de l'efecte del XT amb l'acció de l'avilamicina i el butirat sòdic. Finalment, després de tres anys de col·laboració i donat l'interès de la companyia en desenvolupar nous productes basats en extractes de plantes, hem desenvolupat un mètode in vitro per testar el poder antimicrobià d'un ampli ventall de substàncies derivades de plantes. Al treball in vitro, el nostre objectiu ha sigut desenvolupar un mètode molt simple però realista, utilitzant el contingut de diferent trams del tracte intestinal, obtingut dels porcs sense cap modificació, i incubant-lo curts períodes de temps.Resultats productiusEls resultats productius són molt variables entre experiments. Aquestes variacions són degudes probablement a l'ús de diferent instal·lacions, edats i estats de salut dels animals i la diferent composició de les dietes bassals.Mesures fisiològiques i físiquesLa digestibilitat ileal i rectal i el pH en les diferents part del tracte gastrointestinal s'han estudiat de manera sistemàtica a les tres proves in vivo però no s'han obtingut resultats consistents. Tanmateix, la inclusió de extractes de plantes a la segona prova va provocar un alentiment del buidament gàstric realcionat amb un augment del pH de l'estomac.Poblacions microbianes El resultat més consistent de tots els obtinguts es l'augment de lactobacillus amb la inclusió del XT a les dietes. Malauradament, la rellevància d'aquest augment no està gens clara perquè no va tenir relació directa amb cap benefici productiu. La inclusió del XT ha afectat també altres paràmetres microbians: la concentració de bases púriques i els perfils d'àcids grassos volàtils. Aquest resultats no són molt consistents i de vegades contraris.Paràmetres epitelialsS'han estudiat els efectes del XT a l'estructura epitelial però una vegada més els resultats són molt variables depenent de la prova. De totes maneres queda clar que l'XT exerceix una gran influencia sobre certs paràmetres immunes del epiteli, i s'han de continuar investigant amb tècniques més especifiques.Estudis in vitroEl mètode in vitro s'ha utilitzat amb èxit pe compara diferents additius. Les variacions de fermentació in vitro no només depenen del additiu utilitzat, sinó també de l'edat de l'animal i de la part del tracte gastrointestinal utilitzada d'on s'obté l'inocul. Aquestes variacions s'han d'analitzar amb deteniment.D'aquests estudis podem concloure que les dosis comercials de XT no presenten efectes antimicrobians directes sobre les poblacions microbianes estudiades (lactobacillus i enterobacterias). Utilitzant el contingut de jejú com inocul, es necessiten dosis properes a 10000 ppm per obtenir efectes antimicrobians. D'altre banda, amb dosis més baixes de les substàncies pures s'aconsegueixen efectes similars. Aquestes dosis varien entre 500 i 3000 ppm de carvacrol i cinamaldehid, depenent de la part del tracte gastrointestinal estudiada. Amb tots els productes, la dosis mínima necessària per inhibir la fermentació es sempre menor amb el contingut del jejú. / The main objective of this PhD dissertation is to evaluate the effects of the commercial additive XT (5% carvacrol, 3% cinnamaldehyde, 2% capsicum oleoresin) on productive performance and on different parameters of normal digestive physiology of the early weaned pig: digestibility, pH, epithelial structure, bacterial populations and metabolic activity. It is also an objective of this work to evaluate possible interactions of XT with other ingredients, nutrients and additives included in the diet. This work must be understood in a broader multi-centric research plan organized by the company Pancosma. In particular, the experiments here presented evaluate i) the effects of XT on the above mentioned parameters depending on the CP level and source, ii) the possible interaction between XT and formic acid, and finally the comparison of the effects of XT with the action of avylamycin and butyrate. After three years of collaboration and given the interest of the company in developing new products based on plant extracts, we developed an in vitro methodology to test the antimicrobial effects of a wide range of plant derived substances. Concerning the in vitro method, our objective was to develop a very simple but realistic method able to obtain significant results, using crude intestinal content obtained from the pigs and incubating it for short periods.Productive performanceThe performance results were very variable among the experiments. These variations were probably due to the use of different facilities, age and health status of the animals and the different composition of the basal diets.Physiologic and physical parametersIleal and whole tract digestibility and pH measurements in different parts of the gastrointestinal tract were systematically studied in the three in vivo trials but no consistent effects of including plant extracts were found. However, plant extracts inclusion in the diet in the second trial resulted in a decrease of gastric emptying rate and an increase of pH. Microbial populations The most consistent result in the three experiments was an increase in lactobacilli counts with the inclusion of XT in the diets. However, the relevance of this higher intestinal lactobacilli content is not clear, since there was no direct relation with productive benefits. XT inclusion also had an effect on other microbial parameters: purine bases concentration and VFA profile. However, those results were not very consistent and often were highly controversial.Epithelial parameters The effects of XT on the epithelial structure were studied and, once more, the results were very variable depending on the trial. However, a high influence of XT was found on some immune parameters measured in the epithelium and in the lamina propia, results that encourage continuing investigating these effects with more specific techniques.In vitro studies The in vitro method was successfully used to compare different additives. Variations in in vitro fermentation were found not only depending on the additive used but on the age of the animal and on the gastrointestinal tract part used as source of the inoculum. These variations should be studied in more detail in the future.From these studies, we can conclude that the recommended commercial dose of XT presents no direct antimicrobial effect on the studied populations (lactobacilli and enterobacteria). Doses of near to 10000 ppm are needed to obtain antimicrobial effects in jejunum content. However, lower doses were needed when the pure substances instead of the XT mixture were used. These doses were between 500 and 3000 ppm for carvacrol and cinnamaldehyde, depending on the gastrointestinal tract part studied. The minimum dose of all studied substances to produce antimicrobial effects was always lower for the jejunum than for stomach or cecum content.

Thesis (MSc (Paraclinical Sciences))--University of Pretoria, 2008. / Includes bibliographical references. Also available in print format.

Thesis (M.Sc. (Pharmacology)) -- Mahidol University, 1978. / Supported by the Faculty of Dentistry, Mahidol University and the National Research Council.

Thesis (M.Sc. (Organic Chemistry)) -- Mahidol University, 1976. / Supported by University Development Commission.

Thesis (Ph. D.)--Ohio University, June, 2004. / Includes bibliographical references (leaves 126-138).

Thesis (M.Sc. (Paravet. Studies))--University of Pretoria, 2004. / Includes bibliographical references.

Thesis (MSc (Paravet. Studies))--University of Pretoria, 2004. / Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 67-72). Also available on the World Wide Web.