L'application des biomatériaux est de plus en plus élargie. Le progrès médical suggère l'utilisation des biomatériaux (verres bioactifs, apatites,..) en tant qu'implants selon le besoin de l'organisme. L'objectif de notre travail est de mettre en évidence l'influence biologique des molécules organiques (bisphosphonates, biopolymères et antibiotiques) incorporés dans des matrices de verres bioactifs. De même, notre étude vise à optimiser les meilleures techniques de synthèse et d'association des verres bioactifs à ces molécules. La détoxification des rats mâles de souche « Wistar » exposés au chlorure de nickel par une apatite synthétique a aussi fait l'objet de ce travail. Suite à une perte osseuse provoquée, nous avons démontré que l'utilisation des antibiotiques associés à des verres bioactifs en tant qu'implants osseux, chez des rattes ovariectomisées, permet d'éliminer certains effets indésirables par voie systémique. Ceci a été mis en évidence par l'évaluation des paramètres biochimiques et histologiques du foie et du rein. Aucune variation significative en comparaison avec ceux du témoin négatif n'a été révélée. L'étude in vitro a montré d'une part que l'introduction du Chitosan et surtout de l'antibiotique dans la matrice vitreuse font augmenter l'activité antibactérienne in vitro. Cette étude in vitro a montré d'autre part que la Ciprofloxacine induit un effet néfaste sur les cellules ostéoblastiques et endothéliales. Cet effet est local lorsqu'il s'agit des expérimentations in vivo. Ceci est mis en évidence lors des évaluations du statut oxydant. Les marqueurs du remodelage osseux, l'histologie de l'os et les paramètres physico-chimiques montrent l'effet retardateur de cet antibiotique sur la dissolution de l'implant et par conséquent sur son ossification. La synthèse par le procédé de sol-gel provoque une bioactivité plus importante que celle obtenue par fusion. La bioactivité des verres bioactifs étudiés diffère selon la molécule introduite. Celle-ci est réduite dans le cas de l'association du Clodronate et de Ciprofloxacine in vitro et in vivo. Alors que, le Polyvinyl Alcohol et surtout le Chitosan font modifier la cinétique de cette bioactivité in vivo. Concernant l'hydroxyapatite, nous avons essayé d'explorer son effet détoxifiant chez des rats reçevant le chlorure de nickel. Nos résultats ont montré que le nickel induit un stress oxydant au niveau du foie, du rein, de la rate et du culot érythrocytaire. Des troubles physiologiques ont été observés chez les rats exposés au nickel. Cependant, l'implantation de l'hydroxyapatite protège les rats intoxiqués par le nickel contre ses effets toxiques en diminuant l'état du stress. Le biomatériau utilisé s'avère efficace pour corriger l'équilibre ferrique et phosphocalcique, protéger les fonctions rénale et hépatique, abaisser le taux du nickel osseux et corriger l'anémie. / The application of biomaterials is increasingly widened. Medical progress suggest the use of biomaterials (bioactive glasses, apatites,..) as implants according to the need of the body. The aim of our work is to highlight the biological influence of organic molecules (bisphosphonates, biopolymers and antibiotics) incorporated into matrix of bioactive glasses. Similarly, our study aims to optimize the best synthesis and combination technique of bioactive glasses to these molecules. The detoxification of male rats strain "Wistar" exposed to nickel chloride by a synthetic apatite also has been the object of this work. Following the bone loss induced, we have demonstrated that the use of antibiotics associated with bioactive glass as bone implants, in ovariectomised rats, eliminates some adverse effects systemic. This has been highlighted by the evaluation of biochemical and histological parameters of liver and kidney. Any significant changes in comparison with those of the negative control was revealed. The in vitro study showed in the one hand that the introduction of Chitosan and especially of the antibiotic in the glass matrix can increase antibacterial activity. This in vitro study showed in the other hand that the Ciprofloxacin induces a negative effect on osteoblastic and endothelial cells. This effect is local when it has been an in vivo experiments. This is highlighted by the oxidative status evaluation. Markers of bone turnover, bone histology and physicochemical parameters show the retarding effect of this antibiotic on the dissolution of the implant and consequently on its bone formation. Synthesis by sol-gel method causes a more important bioactivity than melting. The bioactivity of elaborated bioactives glasses will differ depending on the molecule introduced. It is reduced in the case of combination of Clodronate and Ciprofloxacin in vitro and in vivo. While, Polyvinyl Alcohol and especially Chitosan modify the kinetic of the bioactivity in vivo. Concerning the hydroxyapatite, we tried to explore its detoxifying effect in rats receiving nickel chloride. Our results showed that nickel induces an oxidative stress in the liver, kidney, spleen and red cell pellet. Physiological disorders were observed in rats exposed to nickel. However, implantation of hydroxyapatite protects rats intoxicated by nickel against its toxic effects by decreasing the stress status. The used biomaterial is effective to correct ferric phosphate balance, protect kidney and liver function, reduce level of bone nickel and correct anemia.

Orientadores: Celso Aparecido Bertran, Italo Odone Mazali / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-26T18:05:40Z (GMT). No. of bitstreams: 1 Lopes_JoaoHenrique_D.pdf: 497901561 bytes, checksum: bc2ebe969caf9d4e0bc28574f75fae56 (MD5) Previous issue date: 2015 / Resumo: Esta tese está dividida em quatro capítulos. O capítulo I apresenta os fundamentos sobre biomateriais e biovidros. O capítulo II é dedicado a investigar os efeitos da adição de óxido de nióbio (Nb2O5) sobre as propriedades físicas, a estrutura do vidro e a bioatividade de duas séries vítreas derivadas do 45S5 Bioglass® (BG45S5). A composição química do BG45S5 foi modificada pela substituição de 1,3 e 2,6% de P2O5 por Nb2O5 e 1, 2 e 5% do SiO2 pelo Nb2O5, gerando as séries (I) e (II), respectivamente (BGNs). A introdução do Nb2O5 aumenta significativamente a densidade e a estabilidade contra a desvitrificação, como evidenciado pelo parâmetro ?Txg = (Tx - Tg). Os espectros de ressonância magnética nuclear no estado sólido MAS NMR para os núcleos 29Si, 31P e 23Na, espectroscopia Raman e a determinação de algumas propriedades físicas permitiu um entendimento detalhado da estrutura dos vidros BGNs. Para os vidros da série I, o octaedro de NbO6 entra na rede silicato, partilhando os seus vértices com os tetraedros de silício para formar cadeias O-Si-O-Nb-O-Si-O, enquanto que para os vidros da série II, os octaedros NbO6 atuam como agente de reticulação para as cadeias de silicatos. A viabilidade celular e a atividade metabólica foram determinadas utilizando o ensaio de MTT. Os resultados dos estudos in vitro com os vidros BGNs sobre a viabilidade dos osteoblastos e proliferação não mostram diferenças significativas entre BGNs e BG45S5. Os resultados da experimentação in vivo em ratos Wistar sugerem que a presença de Nb2O5 pode efetivamente promover um aumento na bioatividade de BGNs, observado pelo aumento da quantidade formada de osso cortical e trabecular. O capítulo III abrange a investigação da modificação da superfície do biovidro BG45S5 pelo enriquecimento com cálcio, por imersão em banho de sal fundido contendo cálcio (BG45Cas) e o seu efeito sobre a estrutura da superfície, a velocidade de dissolução e também a cinética da formação do fosfato de cálcio. A combinação da microscopia de força atômica e espectroscopia Raman (AFM) permitiu o acompanhamento das mudanças estruturais do BG45S5 submetido a diversos tempos de imersão no banho de sal fundido a 480 °C, enquanto que a fluorescência de raios X (XRF) foi empregada para monitorar a evolução temporal do processo de troca iônica entre Ca2+ e Na+. Os rearranjos estruturais, como resultado da troca iônica, foram sistematicamente investigados no BG45Ca30 pelas espectroscopias FTIR e 29Si e 31P MAS NMR. Os resultados mostram que a quantidade de íons cálcio que entram na estrutura do vidro é maior do que a quantidade de íons sódio que deixa a rede, de modo que, para preservar a eletroneutralidade na rede, ocorrem alterações locais na estrutura que conduzem a uma depolimerização da rede de silicato. A formação da fase de fosfato de cálcio quimicamente equivalente à hidroxiapatita (HA) na superfície do biovidro foi estudada por imersão dos biovidros em HEPES 50,69 mmol L-1 e fluido corpóreo simulado (SBF) durante 2 dias. A camada de apatita formada foi caracterizada pela espectroscopia 31P MAS NMR. A cinética de crescimento da camada de apatita sobre a superfície do BG45Ca30 sugere que a modificação da superfície do vidro não só promove uma redução no tempo para a formação de HA, mas também a formação de hidroxiapatita com maior grau de cristalinidade. Finalmente, o capítulo IV descreve as nossas contribuições, observações finais e sugestões para futuros trabalhos / Abstract: This thesis is divided into four chapters. Chapter I presents background information on the biomaterial and bioglasses. Chapter II is devoted to investigate the effects of adding niobium oxide (Nb2O5) on the physical properties, glass structure and bioactivity of two glasses series derived from the 45S5 Bioglass® (BG45S5). The chemical composition of BG45S5 was modified by replacing 1.3 and 2.6% of P2O5 with Nb2O5 and 1, 2.5, and 5% of SiO2 with Nb2O5, generating series (I) and (II), respectively (BGNs). Adding Nb2O5 significantly increases the density and the stability against devitrification as indicated by ?Txg = (Tx - Tg). The multinuclear 29Si, 31P, and 23Na solid-state MAS NMR spectra of the glasses, Raman spectroscopy, and the determination of some physical properties have generated insight into the structure of the glasses. For the series I glasses, the octahedral niobium take part in glasses network, sharing its corners with silicon tetrahedra forming O-Si-O-Nb-O-Si-O chains, whereas for the series II, NbO6 octahedra act as crosslinker for the silicates chains. Cell viability and metabolic activity were determined using the MTT assay. We investigated the in vitro effect of BGNs glasses on osteoblast viability and proliferation. No significant differences were found between BGNs and BG45S5. Furthermore, in vivo tests in Wistar rats have suggested that the presence of Nb2O5 might actually promote an increase in bioactivity of BGNs, increasing formation of cortical and cancellous bones. The chapter III covers research related to of the surface modification of BG45S5 bioglass (BG45Cas) and its effect on the surface structure, dissolution rate and calcium phosphate formation. BG45Cas were obtained by ion exchange method by immersion in molten salt bath containing calcium. The combination of Raman spectroscopy and atomic force microscopy (AFM) allowed the monitoring of the structural changes of BG45S5 bioglass submitted to increasing durations of immersion in the molten salt bath at 480 °C, whereas X-ray Fluorescence (XRF) was employed to derive the time evolution of Ca2+-Na+ ion exchange process. Structural rearrangements as a result of Ca2+-Na+ ion exchange have been investigated systematically on 45S5 bioglasses by FTIR and 29Si and 31P MAS NMR spectroscopies. Results show that the insertion of calcium ions in the glass structure is higher than the departure of sodium ions. The electroneutrality of the glass structure is preserved with local alterations, which lead to a higher degree of depolymerization of the silicate network. The formation of calcium phosphate layer chemically equivalent to hydroxyapatite (HA) on the bioglass surface was evaluated by immersing the bioglasses in the HEPES 50,69 mmol L-1 and simulated body fluid (SBF) for up to 2 days. This apatite layer was characterized by 31P MAS NMR spectroscopy. The growth kinetics of the apatite layer on the surface of the bioglasses demonstrated that modification of the glass surface (BG45Ca30) cause not only a reduction in time of the formation of HA, but also induced hydroxyapatite phase formation with a higher degree of crystallinity. Finally, chapter IV describes our contributions, final remarks and suggests some ideas for future works / Doutorado / Físico-Química / Doutor em Ciências

Die Regeneration und Rekonstruktion von Knochendefekten stellt eine klinische Herausforderung dar. Überschreitet ein knöcherner Defekt eine kritische Größe, ist das Regenerationsvermögen des Körpers nicht ausreichend, um den Defekt vollständig mit Knochengewebe zu schließen. Um das Einwachsen von Bindegewebe und den Verlust der Stützfunktion des Knochens zu verhindern, ist es notwendig, einen solchen Defekt mit einem Knochenersatzmaterial zu versorgen. Bei Patienten mit einer systemischen Skeletterkrankung, wie Osteoporose, liegen erschwerte Bedingungen für den Heilungsprozess vor. Osteoporose bedingt ist die Remodellierung des Knochens beeinträchtigt. Dies äußert sich in einer verzögerten Knochenheilung sowie in einer veränderten Knochenarchitektur und entstehenden Mikrofrakturen. Die Kombination aus der Fragilität des osteoporotischen Knochens und einer altersbedingten erhöhten Sturzgefahr resultiert in einem mit zunehmendem Alter steigenden Frakturrisiko. Knochendefekte und pathologische Frakturen, die Patienten im Verlauf einer postmenopausalen oder altersbedingten Osteoporose entwickeln, betreffen häufig die Wirbelsäule oder den Schenkel-hals. Die nur langsam oder nahezu nicht heilenden Frakturen gehen nicht nur mit Schmerzen einher, sondern schränken die Patienten auch funktionell in ihrem Alltag ein und können zur Pflegebedürftigkeit und Bettlägerigkeit führen. Die medizinische Versorgung solcher Defekte und Frakturen mit geeigneten Knochenersatzmaterialien ist nicht nur eine klinische, sondern eine interdisziplinäre Problemstellung.

The aim of this Master’s thesis is to investigate the preparation and structure of nanofibres of inorganic and organic biomaterials. Nanofibres of polycaprolactone, chitosane and their composites with hydroxyapatite particle were prepared by centrifugal force spinning process, which uses centrifugal forces for nanofibres spinning. Designed nanofibres can be used in bone tissue engineering. Experimental activity has started with synthesis of hydroxyapatite nanoparticles and preparation of polymer solutions and composite suspensions at different concentrations. The solutions and the suspensions were characterized by density and viscosity which were changed in dependence on temperature and polymer concentration. The solutions and the suspensions were spun at varying speeds and using two different sizes of collectors. The dependence of spinneret head revolution speed, size of collectors and polymer concentration on nanofibres diameter was studied. Biological activity of polycaprolactone and hydroxyapatite/polycaprolactone nanofibres was tested by means of SBF.

Department of Chemistry / MSc (Chemistry) / See the attached abstract below

In this study, we integrated different calcium sources into sol-gel hybrid glass scaffolds with the aim of producing implants with long-lasting calcium release while maintaining mechanical strength of the implant. Calcium(II)-release was used to introduce bioactivity to the material and eventually support implant integration into a bone tissue defect. Tetraethyl orthosilicate (TEOS) derived silica sols were cross-linked with an ethoxysilylated 4-armed macromer, pentaerythritol ethoxylate and processed into macroporous scaffolds with defined pore structure by indirect rapid prototyping. Triethyl phosphate (TEP) was shown to function as silica sol solvent. In a first approach, we investigated the integration of 1 to 10% CaCl2 in order to test the hypothesis that small CaCl2 amounts can be physically entrapped and slowly released from hybrid glass scaffolds. With 5 and 10% CaCl2 we observed an extensive burst release, whereas slightly improved release profiles were found for lower Calcium(II) contents. In contrast, introduction of melt-derived bioactive 45S5 glass microparticles (BG-MP) into the hybrid glass scaffolds as another Calcium(II) source led to an approximately linear release of Calcium(II) in Tris(hydroxymethyl)aminomethane (TRIS) buffer over 12 weeks. pH increase caused by BG-MP could be controlled by their amount integrated into the scaffolds. Compression strength remained unchanged compared to scaffolds without BG-MP. In cell culture medium as well as in simulated body fluid, we observed a rapid formation of a carbonated hydroxyapatite layer on BG-MP containing scaffolds. However, this mineral layer consumed the released Calcium(II) ions and prevented an additional increase in Calcium(II) concentration in the cell culture medium. Cell culture studies on the different scaffolds with osteoblast-like SaOS-2 cells as well as bone marrow derived mesenchymal stem cells (hMSC) did not show any advantages concerning osteogenic differentiation due to the integration of BG-MP into the scaffolds. Nonetheless, via the formation of a hydroxyapatite layer and the ability to control the pH increase, we speculate that implant integration in vivo and bone regeneration may benefit from this concept.

In order to achieve efficient therapeutic effect, it is important to understand the structure of biomaterials that are used in the therapeutic delivery system. This dissertation is dedicated towards understanding the hydrolysis pattern of plasmid DNA (pDNA) delivery vehicles comprised of poly(glycoamidoamine)s (PGAAs) under physiological conditions and effects of subtle changes in the chemical structure of the PGAAs on its biological performance. The unusual hydrolysis of the tartarate and galactarate based PGAAs was investigated by studying the hydrolysis of small model molecules which mimic the repeat unit of the respective polymers. In the case of galactarate and tartarate based molecules with terminal amines showed faster hydrolysis of the amide bonds. In addition for the tartarate based compounds, it was also found that it is necessary to have terminal amine functionality for the intramolecular hydrolysis to occur. The model compounds consists of two amide bonds and were designed symmetric, however amide bond on only one side of the tartarate moiety show underwent hydrolysis. Further studies show that one side of the amine assists the hydrolysis of the amide bond on the other side of the tartarate moiety. The degradation of poly(L-tartaramidopentaethylenetetramine) (<strong>T4</strong>) was also used to study the sustained release of pDNA from the layer-by-layer constructs of <strong>T4</strong>/pDNA. The thickness of the constructs was characterized by ellipsometry while the UV-visible spectroscopy was used to characterize the loading capacity of the constructs for pDNA. The indirect sustained release of pDNA under the physiological conditions with respect to time was characterized by the cellular uptake studies in HeLa cells. The increase in the uptake of the Cy5 labeled pDNA was seen at extended period of eleven days. The integrity of the sustained released pDNA for the transgene expression was characterized with an assay to see the expression of the green fluorescent protein (GFP) from the <strong>T4</strong>/GFP-pDNA layer-by-layer constructs. PGAAs show a very efficient delivery of the pDNA in a non-toxic manner. The chemical structure of the polymer can dictate the binding with pDNA and also the release of the pDNA form the polymer-pDNA complexes. In order to better understand the fundamentals of the nucleic acid delivery and to better design the nucleic acid delivery vehicles, subtle changes in the chemical structure of the PGAAs were designed and studied for the biological activity. The effect of charge type was investigated by designing and synthesizing guanidine based polymer series analogues to galactarate and tartarate based PGAAs (<strong>G1</strong> and <strong>T1</strong>) which incorporate secondary amines as the charge type on the polymer backbone. The guanidine based polymer series, poly(glycoamidoguanidine)s (PGAGs), show very non toxic behavior in HeLa cells at all the different polymer to pDNA ratio (<i>N/P</i> ratio) studied. Interestingly PGAGs are the only non-toxic guanidine containing polymers which are reported in the literature to the date. The cellular uptake of pDNA assisted from the PGAGs is a little higher than PGAAs compared although both the series of polymers show similar transgene expression. The transgene expression in case of PGAGs also imply the release of the polymer-pDNA complexes from the endosome. In another study of structure-bioactivity relationship based on the degree of polymerization (DP) of poly(galactaramidopentaethylenetetramine) (<strong>G4</strong>), it was found that the increase in the DP of <strong>G4</strong> increases the toxicity of the polymers in the HeLa cells. / Ph. D.

Chronic conditions such as obesity, inflammatory bowel disease (IBD), and colitis are associated with gastrointestinal (GI) inflammation and compromised GI barrier integrity. Cocoa may be a potential dietary strategy to mitigate gut-related conditions and been shown to elicit anti-inflammatory, antioxidant, and prebiotic effects. Alkali treatment of cocoa was once thought to reduce its bioactivity, but new evidence suggests it may enhance cocoa's health properties, through the formation of new, potentially bioactive high molecular weight compounds. Inulin, a fructose-containing plant polymer, exerts prebiotic effects and has also been investigated in the mitigation of IBD. This study aims to 1) investigate effects of alkali processing on gut health related bioactivity and phytochemical composition of cocoa and 2) evaluate potential additive benefits of combining cocoa and inulin. Polyphenolic and flavanol compounds in natural cocoa, alkalized cocoa, and inulin powders were characterized using Folin-Ciocalteu (total polyphenols) and 4-dimethylaminocinnamaldehyde (total flavanols) assays, thiolysis , and HILIC UPLC-MS/MS. Treatments of cocoa and inulin were made in 1:2 cocoa:inulin and 1:4 cocoa:inulin mixtures for both natural and alkalized cocoas. Cocoa mixtures, in addition to both cocoa powders and inulin alone, were subjected to an in-vitro digestion to generate material for an in-vitro fecal fermentation. Samples collected from the fermentation at 0, 6, 12, and 24 hours were analyzed via HPLC-MS for microbial metabolites, applied to HT-29 colon cancer cells to assess anti-inflammatory activity, and applied to a florescence assay measuring PLA2 inhibitory activity. The alkalized cocoa powder was found to have a significantly lower concentration of total polyphenols and total flavanols, as well as a lower mDP, suggesting that alkalization may affect larger procyanidins more than smaller flavanol compounds. Inulin enhanced the inhibition of the PLA2 enzyme and enhanced the IL-8 anti-inflammatory properties of cocoa, although the trends were weak. Overall, we did not see any clear, significant effects of alkalization or the addition of inulin to cocoa's colonic metabolite formation or its gut bioactivity in vitro. However, we have demonstrated that colonic fermentation of cocoa may have a negative effect on its bioactivity in vitro. Future research should further explore flavanol DP and bioactivity, fiber's interaction with polyphenols, colonic metabolism of cocoa, and cocoa's gut health effects in vivo. / Master of Science in Life Sciences / Gut conditions like obesity-associated inflammation and inflammatory bowel disease are highly prevalent, debilitating, and currently have no cure. Cocoa has been investigated as a possible dietary strategy for the mitigation and prevention of chronic inflammatory gut conditions due to its anti-inflammatory and enzyme inhibiting properties. Most attribute these effects of cocoa to its abundance of compounds called polyphenols. It is widely thought that the ability of cocoa to promote health is lost when cocoa beans are processed, because of the loss of polyphenols. Alkalization, or "Dutching", is an optional step in cocoa processing that some manufacturers perform to enhance flavor and color formation. Dutching cocoa can promote the polymerization of many smaller, flavanol, protein, and other compounds into larger, indigestible compounds. These indigestible compounds will not be absorbed in the small intestine and may be broken down in the large intestine by colonic bacteria, forming new metabolites. We obtained cocoa powders, one natural (not alkalized) and one alkalized and compared them in terms of content of polyphenols, bioactivities, and anti-inflammatory abilities. Additionally, we added a known prebiotic, inulin, to our cocoa formulations to determine if there are additive benefits of cocoa and inulin together. Ultimately, we found that alkalized cocoa contained lower concentrations of all polyphenolic compounds, even the larger compounds. Inulin enhanced the inhibition of digestive enzymes and the anti-inflammatory properties of cocoa, though not significantly. Inulin also reduced the pH (i.e. increased the acidity) of a simulated gut environment, which may be beneficial. Alkalization did not significantly affect cocoa's enzyme inhibitory activity or anti-inflammatory activity. Overall, the addition of inulin to cocoa does not seem to be effective in increasing cocoa's ability to treat and prevent gut diseases, but more information is needed.

Yes / Both the season and region in which propolis is collected influence its chemical composition, resulting in variations in biological activity. Significant differences in composition and concentration of certain chemical compounds in propolis make standardisation and quality control challenging. In addition, the lack of uniformity in evaluation methodology and analytical techniques, make it extremely difficult to correlate data across the climatic zones. In this report, we focus on the gaps in propolis research and the challenges they pose for commercialisation, with suggestions as to how we might address them. We hope to stimulate further research which explores the holistic nature of propolis in order to derive a propolis bioactivity standard.

Thesis (MSc (Biochemistry))--University of Stellenbosch, 2009. / Sutherlandia frutescens (S. frutescens), sub-species microphylla, is a member of the Fabacea family and is used as a herbal remedy for the treatment of several ailments which include influenza, diabetes, cancer, tuberculosis, chronic fatigue syndrome, rheumatoid arthritis, anxiety, clinical depression, and more recently, those living with human immunodeficiency virus/ acquired immune deficiency syndrome (HIV/AIDS) (1-4). Many of the symptoms of these ailments are associated with a perturbation of the stress response which may be associated with disorders of the endocrine system. Of all the traditional plants in South Africa, S. frutescens is regarded the most profound in that it is a multipurpose traditional remedy. The plant has enjoyed a long history of use and reports indicating its efficacy as a safe treatment for various health conditions have added to the popularity of this medicinal plant. The extracts of S. frutescens have been shown to exhibit anti-proliferative effects on cancer cells, antioxidant activity, and to possess anti-diabetic and anti-inflammatory potential (5, 6), providing scientific evidence for its therapeutic use in the treatment of cancer and diabetes. However, this study focuses on the potential use of this medicinal plant in the treatment of stress and stress related diseases. Chronic stress is characterized by elevated plasma levels of glucocorticoids. These steroid hormones are synthesized in the adrenal cortex in a series of reactions involving the steroidogenic enzymes. The major aim of this thesis was the determination of the influence of S. frutescens extracts on the adrenal cytochrome P450 enzymes. Aqueous, methanol and chloroform S. frutescens extracts were prepared and the interaction with the cytochrome P450 enzymes was investigated. The effect of these extracts towards progesterone (PROG), deoxycortisol and deoxycorticosterone (DOC) binding to the cytochrome P450 enzymes as well as their influence on the metabolism of these steroid substrates was investigated. A similar study (7) showed that compounds from the S. frutescens extracts could interact with these enzymes and possibly affect adrenal steroidogenesis. This study further investigates the bioactive properties of the plant material in terms of the influence of S. frutescens on the cytochrome P450 enzymes and the effect of the manufacturing process on the bioactivity of the plant.