A common strategy employed to destroy harmful bacteria is to disrupt the bacterial membrane through the action of pore-forming anti-microbial peptides. The manner in which the peptides arrange themselves spatially to form a pore in the membrane, which is important for understanding both the mechanism of pore formation and pore function, is a topic of current debate. We contrast the response of a model membrane bilayer to the presence of solid, cylindrical nanoparticle insertions, when the bilayer is composed of persistent worm-like chains and when it is composed of flexible Gaussian chains. We use self-consistent field theory, with the appropriate single-chain propagator, to describe the amphiphilic star-like triblock copolymers composing the membrane and the solvent. The nanoparticle surfaces are designed to have patches that prefer either the solvent or the tail groups of the copolymers, and the nanoparticles are fixed in space. Using this model with polymers in the lamellar phase, we investigate the question of pore-formation, nanoparticle insertion and hydrophobic mismatch in lipid bilayers and the effect that chain rigidity has on these particular interactions. We find that the main effect of increased chain rigidity is that it increases the free energy scaling and the significance of the energy barriers associated with these pore-forming processes. These results demonstrate the importance of using a more realistic persistent chain when modelling pore formation. / NSERC, CFI, SHARCNET

>Magister Scientiae - MSc / Marine invertebrate associated (MIA) bacteria are an important source of bioactive secondary metabolites with the potential to address the current anti-microbial resistance crisis experienced globally. Secondary metabolites (SM) have historically yielded several compounds with pharmaceutical applications such as anti-viral, anti-microbial, anti-cancer, anti-inflammatory and anti-parasitic. This study aimed to use bioassay and genomic approaches in the identification of MIA bacteria isolated from South African marine invertebrates as a source of bioactive compounds and the characterisation of the produced SMs using analytical techniques. A total of 23 MIA bacteria were cultured under different conditions (one strain many compounds approach (OSMAC)) to evaluate their ability to produce anti-microbial compounds against a panel of indicator strains namely Escherichia coli 1699, Bacillus cereus ATCC10702, Pseudomonas putida ATCC12633, Mycobacterium aurum A+, Staphylococcus epidermidis ATCC14990, Aspergillus fumigatus MRC and Candida albicans NIOH.

Thesis (MSc (Biochemistry))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Due to a global lack of access to potable water, a problem particularly affecting people in developing countries and the poor, improvement on existing water purification methods are necessary to provide more cost effective, accessible and efficient methods of water purification. In drinking water systems, biofilms are a potential source of contamination, which can affect the biological stability and hygienic safety of water. In industrial water systems, biofilms can cause corrosion, resistance in flow systems and a decrease in efficiency of membranes. Nanotechnology has been identified as a technology to utilize in water purification problem solving. Alternatives to the use of chemical biocides and antibiotics need to be investigated therefore; the focus of this study was the fabrication and characterization of polymer nanofibers containing silver nanoparticles as biocide and anti-biofouling nanofibers with hydrolytic enzymes immobilized on the surface. The aim of this study was to synthesize and compare poly (vinyl alcohol) (PVA) nanofibers and poly (acrylonitrile) (PAN) nanofibers with silver nanoparticles to determine which type of fiber will be the most appropriate for application in water sanitation. The two types of fibers were to be compared based on morphology, silver nanoparticle content, physical distribution of silver nanoparticles, levels of silver leaching from the fibers in water, which could imply toxicity, and most importantly, anti-microbial efficacy. Back scattering electron images revealed that silver nanoparticles in PVA nanofibers were more evenly dispersed than in PAN nanofibers, but that PAN nanofibers had higher silver nanoparticle content. This was confirmed by energy dispersive X-ray (EDX) analysis. Both PVA and PAN nanofibers containing silver nanoparticles had excellent anti-microbial activity, with PVA nanofibers killing between 91% and 99% of bacteria in a contaminated water sample and PAN nanofibers killed 100%. When investigated by SEM, the biocidal effect of PAN nanofibers containing silver nanoparticles can be observed as morphological changes in the cell walls. Neither PVA nor PAN nanofibers leached silver into water. PVA is a non-toxic and biodegradable synthetic polymer, and PVA-silver nanofibers have excellent anti-microbial activity, making it applicable in water sanitation in an environmental conscious milieu. PAN nanofibers are more conductive to the formation of silver nanoparticles, have higher silver nanoparticle content, allowing the complete sanitation of pathogenically contaminated water samples. PAN nanofibers also have better longevity and strength in water, making it ideal for water filtration and sanitation in higher throughput systems. Furthermore, immobilized enzymes are being investigated as possible alternatives to inefficient conventional methods of controlling and removing biofilms from filtration systems. This study demonstrates the covalent immobilization of two industrial proteases and an amylase enzyme onto polymer nanofibers widely used in filtration membranes. Confirmed by FTIR, these nanofibers were successfully activated by amidination, allowing the covalent immobilization of respectively two serine proteases and an α-amylase onto the fibers. When inspected visually, fibers largely retained their original morphology after activation and enzyme immobilization. Immobilized enzymes were, however visible as aggregated particles on the nanofiber surfaces. The large surface area to volume ratio provided by the nanofibers as immobilization surface, allowed sufficient amounts of enzymes to be immobilized onto the fibers so that all enzymes retained above 80% of the specific activity of the free enzymes. For each of the immobilized enzymes, just below 30% of initial activity was retained after 10 repeated cycles of use. Fibers with immobilized enzymes on their surface did not support the growth of biofilms, as opposed to plain nanofibers, which did support the growth of biofilms. When considering the combined advantages of this effective immobilization process, the robustness of the enzymes used in this study, and their effectiveness against biofilms in their immobilized state, a valuable addition has been made to technology available for the control of biofilm formation on filtration membranes, and could potentially be employed to control biofilm formation in water filtration systems. A combination of anti-microbial and anti-biofouling nanofibers into a single nanofiltration product may prove to be highly applicable in water sanitation systems. / AFRIKAANSE OPSOMMING: As gevolg van 'n wêreldwye gebrek aan toegang tot drinkbare water, 'n probleem wat veral mense in ontwikkelende lande en armes raak, is dit van belang dat bestaande metodes van watersuiwering verbeter word om voorsiening te maak vir meer koste-effektiewe, toeganklike en doeltreffende metodes van watersuiwering. In drinkwater stelsels is biofilms 'n potensiële bron van besoedeling, wat die biologiese stabiliteit en die higiëniese veiligheid van water beïnvloed. In industriële waterstelsels kan biofilms tot die verwering van pyplyne lei, weerstand in die stroomstelsels veroorsaak en 'n afname in die doeltreffendheid van membrane veroorsaak. Nanotegnologie is geïdentifiseer as 'n tegnologie wat aangewend kan word in watersuiwerings probleemoplossing. Alternatiewe vir die gebruik van chemiese antimikrobiese middels moet dus ondersoek word. Hierdie studie fokus dus op die vervaardiging en karakterisering van polimeer nanovesels met silwer nanopartikels wat ingesluit is as antimikrobiese middel en anti-biofilm vesels met hidrolitiese ensieme geïmmobiliseer op die oppervlak. Die doel van hierdie studie was om poli (viniel alkohol) (PVA) nanovesels en poli (akrielonitriel) (PAN) nanovesels te sintetiseer waarby silwer nanopartikels ingesluit is, en te bepaal watter tipe vesel die mees geskikte sal wees vir die gebruik in water sanitasie. Die twee tipes vesels is met mekaar vergelyk gebaseer op morfologie, silwer nanopartikel inhoud, fisiese verspreiding van silwer nanopartikels, vlakke van silwer uitloging vanuit die vesels in water, wat toksisiteit tot gevolg kan hê, en die belangrikste, antimikrobiese effektiwiteit. Terug verstrooiing elektron beelde het aan die lig gebring dat die silwer nanopartikels in PVA nanovesels meer eweredig versprei was as in PAN nanovesels, maar dat PAN nanovesels 'n hoër silwer nanopartikel inhoud gehad het. Dit is bevestig deur “energy dispersive X-ray” (EDX) analise. Beide PVA en PAN nanovesels met silwer nanopartikels het uitstekende antimikrobiese aktiwiteit getoon, met PVA vesels wat tussen 91% en 99% bakterieë in besoedelde water monsters kon doodmaak en PAN vesels wat 100% bakterieë kon uitwis. Wanneer vesels ondersoek is met ʼn skandeer elektronmikroskoop (SEM), kon die antimikrobiese effek van PAN vesels met silwer nanopartikels as morfologiese veranderinge in die selwande waargeneem word. Nie PVA of PAN nanovesels loog silwer uit in water nie. PVA is 'n nie-toksiese en bioafbreekbare sintetiese polimeer, en PVA-silwer nanovesels het uitstekende antimikrobiese aktiwiteit, wat dit van toepassing maak op water sanitasie in ʼn omgewings bewuste milieu. PAN vesels is meer gunstig tot die vorming van silwer nanopartikels, en het 'n hoër silwer nanopartikel inhoud, dus word patogeen besoedelde water volledig gesteriliseer. PAN vesels het ook 'n beter langslewendheid en weerstandige sterkte in water, wat dit ideaal vir water filtrasie en sanitasie in hoër deursettings stelsels maak. Geïmmobiliseerde ensieme word ook ondersoek as moontlike alternatiewe tot ondoeltreffende konvensionele metodes van beheer en die verwydering van biofilms uit water stelsels. Hierdie studie toon die kovalente immobilisasie van twee industriële proteases en 'n amilase ensiem op polimeer vesels wat gebruik word in filtrasie membrane. Bevestig deur FTIR, is PAN vesels suksesvol geaktiveer deur amidinasie, sodat die kovalente immobilisasie van onderskeidelik twee serien proteases en 'n α-amilase op die vesels moontlik is. Met visuele ondersoek kan gesien word die vesels behou grootliks hul oorspronklike morfologie na aktivering en ensiem immobilisasie. Geïmmobiliseerde ensieme is egter sigbaar as saamgevoegde deeltjies op die nanovesel oppervlaktes. Die groot oppervlakarea: volume-ratio van die vesels wat dien as immobilisasie oppervlak, laat toe dat voldoende hoeveelhede van ensieme geïmmobiliseer word sodat alle ensieme meer as 80% van die spesifieke aktiwiteit van die vrye ensieme behou. Vir elk van die geïmmobiliseer ensieme, is net minder as 30% van die aanvanklike aktiwiteit behou na 10 siklusse van hergebruik. Vesels met geïmmobiliseerde ensieme op hul oppervlaktes het nie die groei van biofilms ondersteun nie, in teenstelling met gewone vesels, sonder ensieme, wat die groei van biofilms ondersteun. As die gesamentlike voordele van hierdie doeltreffende immobilisasie proses, die robuustheid van die ensieme en hulle doeltreffendheid teen biofilms in hul geïmmobiliseerde toestand in ag geneem word, is ʼn waardevolle toevoeging gemaak tot tegnologie wat beskikbaar is vir die beheer van biofilm vorming op filtrasie membrane, en dit kan potensieel gebruik word om biofilm vorming filter stelsels te beheer. Die kombinasie van anti-mikrobiese en anti-biofilm vesels in ʼn enkele nanofiltrasie produk moet nagestreef word, omdat dit hoogs van toepassing sal wees in water sterilisasie stelsels.

No description available.

The microbiota has a strong influence on health and disease in humans. A causative shift favoring pathobionts is strongly linked to diseases. Therefore, anti-microbial agents selectively targeting potential pathogens as well as their biofilms are urgently demanded. Here we demonstrate the impact of ethyl pyruvate, so far known as ROS scavenger and antiinflammatory agent, on planktonic microbes and biofilms. Ethyl pyruvate combats preferably the growth of pathobionts belonging to bacteria and fungi independent of the genera and prevailing drug resistance. Surprisingly, this anti-microbial agent preserves symbionts like Lactobacillus species. Moreover, ethyl pyruvate prevents the formation of biofilms and promotes matured biofilms dissolution. This potentially new anti-microbial and anti-biofilm agent could have a tremendous positive impact on human, veterinary medicine and technical industry as well.

Healthcare-associated infections present an escalating worldwide issue, further intensified by the emergence of antimicrobial resistance and the spread of pathogens on surfaces. Current infection prevention methods have shown limited effectiveness, leading to several health issues, an overuse of antibiotics, and a continuous threat of surface recontamination. In response, extensive research has focused on bioinspired omniphobic smart coatings that effectively reduce the contact area available for pathogen attachment, achieved through an increase in surface roughness and apparent surface energy. This thesis introduces a new class of an omniphobic spray-coating, featuring hierarchical structured polydimethylsiloxane (PDMS) microparticles coated with gold nanoparticles, encompassing primary microscale (~0.23 𝜇m) and secondary nanoscale (~5 nm) buckyball and labyrinth wrinkles. This substrate-independent coating efficiently repels a wide range of liquids, including pathogens, even under harsh conditions like high temperatures, ultraviolet (UV) exposure, and abrasions. Repellency tests comparing coated and uncoated gloves revealed that uncoated gloves spread contamination to 50 secondary surfaces, while coated gloves transferred fewer bacteria and viruses to just three and two surfaces, respectively. The investigation extended to the coating's biocidal capabilities, incorporating gold nanoparticles functionalized with mercapto-silane to create a "Repel and Kill" coating. This process initiates chemisorption through thiol-gold bonding, allowing for the formation of diverse surface structures, including three-dimensional self-assembly, multilayers, and island structures. These modifications significantly enhance the roughness and hydrophobicity of the gold nanoparticles, amplifying their biocidal effectiveness. The wrinkled structure of PDMS contribute to repellency, while the functionalized gold nanoparticles play a crucial role in the antimicrobial property. This enhancement was evident in the antibacterial tests, which exhibited an immediate 99.90% reduction in bacterial adhesion for both MRSA and Pseudomonas aeruginosa (P. aeruginosa), followed by an additional 99.70% and 99.90% reduction in bacterial growth after 8 hours for MRSA and P. aeruginosa, respectively. Moreover, the coating's antiviral properties were confirmed, demonstrating a 98% reduction in the transfer of the bacterial virus Phi6. Recognizing the role of hospital fabrics as potential reservoirs for infection transmission, primarily due to their ability to sustain bacterial growth for extended periods, especially in the presence of bodily fluids, we took further steps to modify the wrinkled PDMS microparticles. This involved the incorporation of silver nanoparticles, capped with a positively charged ligand known as branched polyethyleneimine (bPEI). Additionally, we integrated a colorimetric sensor, giving rise to the "Repel, Kill, and Detect" smart coating. The transition of color from blue to green-yellow provided a tangible indicator of contamination detection based on the acidic mileu of the biofilms. To evaluate its realworld effectiveness, we conducted simulations of infection transmission in hospital environments, resulting in a remarkable reduction in pathogen adhesion from urine and feces by 99.88% and 99.79%, respectively, compared to uncoated fabrics. To further enhance the validation of our results, we employed a powerful deep learning network architecture, that determined whether the surfaces are contaminated or safe. In the face of evolving health challenges, this coating emerges as a resilient and adaptable solution, promising to enhance overall safety and alleviate the burden of infectious diseases. / Thesis / Doctor of Engineering (DEng) / The prolonged survival of pathogens on surfaces, significantly highlighted by the COVID-19 global pandemic, has intensified the urgency of addressing contamination on high-touch surfaces. Engineered surface coatings with repellent properties have emerged as a long-lasting and health-conscious solution for infection prevention and control. In this thesis, we introduce a new class of multifunctional engineered coatings featuring hierarchical structures adorned with biocidal nanoparticles and an integrated colorimetric sensor. We comprehensively investigate these coatings' multifunctional capabilities to repel, exterminate, and detect contaminants. Through specific characterization tests involving a wide range of pathogens, including viruses, bacteria, and fungi, within complex biological fluids like urine and feces, this research culminates in the development of surface coatings equipped with both antimicrobial and pathogen-sensing capabilities. In addition to advancing our understanding of surface hierarchy and chemical modifications for repellency and biocidal activity, this thesis yields insights into the dynamics of biofouling and pathogen transfer, with the overarching goal of reducing pathogen transmission via surfaces.

No description available.

Resumo: Neste trabalho estudou-se a estrutura, função e mecanismo de ação do peptídeo antibacteriano Protonectarina-MP (isolado de veneno da vespa social Protonectarina sylveirae) tendo seu resíduo C-terminal nas formas ácida (-OH) e amidada (-NH2). Os peptídeos foram sintetizados, utilizando-se a estratégia Fmoc, purificados por cromatografia líquida de alta performance. O monitoramento do material sintético foi feito por espectrometria de massas ESI-MS e por seqüenciamento através de Química Degradativa de Edman. A estrutura secundária foi investigada pelo uso de espectroscopia de dicroísmo circular e modelagem molecular. Atividade lítica (extravasamento) e interação do resíduo de triptofano em vesículas foram investigadas pelo uso de espectrômetro de fluorescência. Foram realizados ensaios sobre as interações desses peptídeos em meio de vesículas zwitteriônicas e aniônica, formando complexos proteolipossomos que foram submetidos à troca isotópica H/D monitorada por espectrometria de massas ESI-MS e MS/MS. Além disso, foram realizados ensaios biológicos de atividade hemolítica, de desgranulação de mastócito, de liberação da enzima citoplasmática Lactato Desidrogenase e de atividade antimicrobianas. Os dados de CD revelam uma tendência dos peptídeos se estruturarem em hélice-α em ambiente hidrofóbico e em ambiente de membranas. Porém, o mesmo não pode ser observado em meio aquoso. Os modelos obtidos para ambos os peptídeos por modelagem molecular mostram uma estruturação em hélice-α anfipática. Nos ensaios de atividade lítica em vesículas, os peptídeos apresentaram um processo com cooperatividade positiva, com curvas de dose-resposta que mostram uma dependência sigmoidal com a concentração do peptídeo. Os resultados da fluorescência do triptofanos mostram um deslocamento da emissão para a região de onda do azul para o peptídeo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the present work was studied the structure, function and mechanism of action of the antibacterial peptide Protonectarina-MP (isolated from venom of social wasp Protonectarina sylveirae) with its carboxyamidation (-NH2) and carboxyl-free (-OH) Cterminal forms. The peptides were manually synthesized on-solid phase by using Fmoc strategy and purified under HPLC. The homogeneity of the synthetic material was analyzed by ESI mass spectrometry and Edman Degradation Chemistry. The secondary structure was investigated through circular dichroism (CD) spectroscopy and molecular modeling. Lytic activity and peptides interaction with the membranes was also investigated through tryptophan emission, by fluorescence spectrometry. The interaction of peptides with zwitterionic and anionic vesicles was investigated through the combination of H/D exchange and ESI-mass spectrometry. Some biological activities, like: mast cell degranulation, release of cytoplasmic enzyme lactate dehydrogenase, hemolysis and antibiosis were investigated for both peptides. The CD spectra revealed that the peptides in hydrophobic environments or in presence of biological membranes have the tendency to form helix conformations; however, organized structures were not observed in aqueous or buffer solutions. The models obtained by molecular modeling show that both peptides form an amphipathic α-helix. The peptides presented a positive cooperative process in the lytic activity of vesicles, with dose-response curves presenting a sigmoidal dependence with the peptide concentration. The results of the fluorescence of tryptophans showed a shift of the emission wavelength to the blue region of the peptide Protonectarina-MP (-NH2), which was not observed for its analogue presenting the C-terminal residue in free acid form. This is indicating a greater interaction of the amidated peptide in membranes, when compared to the peptide... (Complete abstract click electronic access below) / Orientador: Mario Sergio Palma / Coorientador: João Ruggiero Neto / Banca: Ivo Lebrun / Banca: Pietro Ciancaglini / Mestre

Philosophiae Doctor - PhD / Introduction: Plant extracts and herbal preparations are often marketed as natural and safe alternatives to conventional medicines for the prevention and treatment of a variety of ailments, without proof of efficacy and safety. Cardiovascular, hematopoetic, hepatic and renal impairment resulting from the use of conventional drugs is widely acknowledged. However, there is less awareness of the potential toxicity of herbal preparations and other botanicals, many of which are widely perceived by the public as being effective and harmless, and are commonly used for self medication without supervision. In addition, potential interactions between herbal medicines and conventional drugs may compromise with patient management. In the safety evaluation of most substances, non human primates are preferred to rodent species for preclinical animal safety studies, because of their biological similarity to humans. They are regarded to be the best metabolic models for humans in a broad range of investigations. Additionally, a disadvantage of using small animal species in toxicological testing is that they require higher doses of drugs and more frequent administrations than in larger species. In light of these considerations, vervet monkeys are used here to investigate toxicity of a plant-derived triterpene, oleanolic acid. The focus is to determine effects of different concentrations of this triterpene on the cardiovascular, hematopoetic, hepatic and renal systems. Materials and methods: 12 male vervet monkeys used in this study were equally divided into four groups, i.e. three treatment groups (4, 10 and 25 mg/kg bodyweight), and one control group. Each individual in a treatment group received a specified concentration of oleanolic acid in food for 16 weeks. Monkeys in the control group received the vehicle (food) alone. Bodyweight, body temperature, respiratory rate, heart rate, systolic pressure, diastolic pressure, and mean arterial pressure were recorded from ketamine-anaethetized monkeys at baseline and every second week until week 16. In addition, blood samples were collected at baseline and every fourth week for clinical biochemistry indicators (serum electrolytes, enzymes, proteins, lipids, nitrogenous compounds, bilirubins and glucose) and hematological tests (red cell count and its indices, hemoglobin, haematocrit, white blood cell and differential count and platelet count). Results: No animal showed deviation from their normal behavioral patterns, food and water intake, was in poor health or died during and after completion of the study. The average bodyweights were not statistically significantly different between controls and the treated groups. The biphasic changes in the average body temperature of treated monkeys were similar to those seen in the control group during the first eight weeks of the study. No statistically significant differences were found in body temperature determinations between controls and the treated groups. Fluctuations observed in the respiratory rates of the treated monkeys were not statistically significantly different from that of the control group. Although not statistically significantly different from the controls, the systolic, diastolic and mean arterial pressures in the group treated with 25 mg/kg oleanolic acid were lower at week 16 compared to baseline, while those of the groups treated with 4 and 10 mg/kg oleanolic acid were relatively unchanged. Except for a reduction in systolic pressure of the control group, other blood pressure parameters were stable. Heart rates in the treated groups were not statistically significantly different from those in the controls. In all groups, except the control, high density lipoprotein concentrations were higher at week 16 compared to baseline. Fluctuations in low-density lipoprotein and total cholesterol concentrations were similar between controls and the treated groups. The triglycerides were lower at week 16 compared to baseline for all four groups. Upward trends from baseline to the end of the study were observed in creatine kinase concentrations of the controls and the groups that received 4 and 25 mg/kg. Concentrations of this enzyme were unchanged in the group that received 10 mg/kg oleanolic acid between baseline and the end of the study. No statistically significant differences were found with cholesterol, triglyceride and creatine kinase concentrations between treated groups and the controls. Serum concentrations of aspartate aminotransferase were unchanged in the controls and the groups treated with 4 and 10 mg/kg oleanolic acid, but changes in this parameter over time were statistically significantly different (P = 0.0452) from the controls in the group that received 25 mg/kg oleanolic acid. Despite wide fluctuations in the alanine aminotransferase concentrations in the groups that received 4 and 25 mg/kg oleanolic acid, no statistically significant differences were found with any of the treated groups compared to the controls. No statistically significantly different changes were seen in alkaline phosphatase activities between controls and the treated groups. Reductions in gamma-glutamyl transferase activities in the groups that received 4 and 25 mg/kg oleanolic acid were not statistically significantly different from concentrations of this enzyme in the controls. In addition, no statistically significant differences were evident between controls and the group that received 10 mg/kg oleanolic acid. There were no statistically significantly different changes in the total and conjugated bilirubin and glucose concentrations between controls and the treated groups. Fluctuations over time in the serum albumin and globulin concentrations were similar between treated groups and the controls, whereas total protein concentrations were relatively constant. Consequently, no statistically significant differences were found between controls and the treated groups. Wide fluctuations were observed in the creatinine concentrations of the groups that received 4 mg/kg oleanolic acid, while no such changes were encountered in the controls and the group that received 10 and 25 mg/kg oleanolic acid. Serum urea concentrations increased in all groups over time, except for the group that received 10 mg/kg oleanolic acid. Both urea and creatinine concentrations in the treated groups were not statistically significantly different from concentrations in the controls. Serum concentrations of sodium, chloride, potassium, calcium and magnesium and phosphate in the treated groups were not statistically significantly different from these electrolyte concentrations in the controls. Decline in red cell and hemoglobin concentrations of the controls and the group that received 25 mg/kg oleanolic acid were not statistically significantly different between these groups. In addition, no statistical significant differences were found in red cell and hemoglobin concentrations between controls and the groups that received 4 and 10 mg/kg oleanolic acid. Controls and the treated groups showed upward trends in haematocrit concentrations. Mean corpuscular volumes were statistically significantly increased; P = 0.0027 (4 mg/kg), P = 0.0010 (10 mg/kg), and P = 0.0022 (25 mg/kg), while mean corpuscular hemoglobin concentrations were statistically significantly reduced; P = 0.0017 (4 mg/kg), P = 0.0004 (10 mg/kg), P = 0.0002 (25 mg/kg) in the treated groups as compared to the controls. No statistically significant differences were evident in the concentrations of mean corpuscular hemoglobin between controls and the treated groups. White blood cell counts of the treated groups were not statistically significantly different from those of the controls throughout the study period. No statistically significant differences were found in the differential white cells and platelet counts between treated groups and the controls. Discussions: The results of this study showed that administration of oleanolic acid had no effects on the general wellbeing, bodyweights, body temperature, respiratory and heart rates, and blood pressure of vervet monkeys. A statistically significant increase in the aspartate aminotransferase activity of the group treated with 25 mg/kg oleanolic acid, together with the increase in the alanine aminotransferase levels during the same time period, might indicate oleanolic acid-induced hypersensitivity, and accordingly hepatocellular alteration. However, since serum concentrations of these enzymes returned to baseline levels, as well as the absence of variations over time in other parameters of the hepatic function, particularly alkaline phosphatase activity, it is likely that there was no underlying subacute liver disease. Serum renal function parameters also appeared to be within normal physiological limits. No pronounced changes were observed in the hematological parameters of monkeys that received oleanolic acid. Conclusion: This study's results, suggest that oleanolic acid does not produce cumulative liver enzyme alterations, and has no detrimental effects on the renal, hematopoetic and cardiovascular systems of vervet monkeys.

A pre-eminent emulsion-based micellar drug delivery system, "microemulsion", comprising drug in oil or water phase, stabilized by surfactants and co-surfactants, has been evidenced to have a phenomenal role in a number of applications. Oils play an important role in the formation of ME and increase the drug absorption at the site of action. Oils employed in microemulsion formulation solubilize lipophilic drug. As the concept of "natural" therapies is recently gaining importance amongst researchers all over the world, scientists are employing essential oil as an organic component in this system. The active components of essential oils include flavonoids, phenylpropanoids, monoterpenes and polyunsaturated mega-6-fatty acids. These oils are enriched with characteristic intrinsic properties such as anti-oxidant, anti-bacterial, anti-viral, etc., bestowing enhanced supremacy to the whole microemulsion system. This mini-review is the first to document various types of essential oils employed in microemulsion systems and highlight their therapeutic potential and applications as drug delivery vehicles. Key inferences from this study suggest: 1) Clove oil is the most explored oil for incorporation into a microemulsion based system, followed by peppermint and Tea Tree Oil (TTO). 2) Penetration enhancing effects of these oils are due to the presence of terpenic constituents. 3) Essential oil based microemulsions protect volatility of ethereal oils and protect them from degradation in the presence of light, air, temperature. 4) These systems may also be explored for their applications in different industries like aromatherapy, food, drink, fragrance, flavour, cosmeceutical, soap, petroleum and pharmaceutical industry.