Humic substances are a group of ubiquitous compounds formed during the decay of plant and animal residues in the environment. These substances can be divided into humic acid, fulvic acid and humin on the basis of its solubility in water as a function of pH. Fulvic acid is the fraction that is soluble in water under all pH conditions and is usually extracted from brown coal and is therefore associated with high levels of heavy metals. These heavy metal levels have become a point of concern and a unique method for synthesizing fulvic acid from a carbohydrate source has been subsequently developed and patented in an attempt to address this problem. The purpose of this study was therefore, to test the topical and systemic safety and efficacy of this new carbohydrate derived fulvic acid (CHD-FA) product. Initial in vitro screening using the Kirby-Bauer disk diffusion method indicated that the product was active against the Staphylococcus aureus test organisms used (ATCC 12600 and P3938). Results showed that not only was it as effective as the oxacillin control, but in the case of a more virulent strain of S. aureus, the CHD-FA (3.9% w/v) proved more active. Subsequently, the ability of the product to cross full-thickness skin was ascertained using Franz-type diffusion cells fitted with 100ìm skin disks obtained from rats. At the end of a 12-hr period, results indicated that up to 20% of the CHD-FA at a pH of 2.9 was able to cross the skin barrier. Divided into 6 phases, extensive animal safety studies were conducted on the product. In phase I, toxicity and sensitivity to topical application was examined by applying the product to the ears of mice over a period of 30 days. Phase II and III was undertaken to study the long term effects (6-weeks and 6-months) of CHD-FA ingestion (150 mg/kg body mass) whilst phase IV tested the effects of CHD-FA ingestion on pregnant rats and their off-spring. Phase V was an acute toxicity study in which rats received a single oral dose of CHD-FA (150mg/kg bw) and then observed for a period of 7 days. Phase VI was a 6-week chronic study in which the animals received 100mg/kg bw daily for the duration of the experiment. Results obtained in all studies showed that CHD-FA is safe for topical as well as, oral use at the doses tested. In addition, it is safe for use during pregnancy. Finally, the in vivo anti-microbial efficacy of the CHD-FA was examined using an infected wound healing model. A pilot study indicated that the animals used should be immunocompromised and the wounds inoculated with a Staphylococcus aureus (ATCC 12600) concentration of 1x1010 CFU/ml. Results from the main study showed that topical applications of the CHD-FA (pH 1.98) product at a concentration of 1.75% w/v over the 5-day period produced a wound healing pattern similar to that of the positive fuscidic acid control. In contrast, animals receiving an oral treatment of the product did not produce a pattern different from that of the water control group. In conclusion, CHD-FA has been shown to be safe and effective in treating S. aureus infections in vitro and in animal models. This study indicates that the next phase of human studies is certainly warranted. / Dissertation (MSc)--University of Pretoria, 2009. / Pharmacology / unrestricted

Objectives: In this pilot study, our intention was to ascertain what formulation of a carbohydrate-derived fulvic acid (CHD-FA) topical applicator was optimal for patients to use during a larger study where the efficacy of fulvic acid (CHD-FA) in treating moderate acne vulgaris will be investigated. Methods: 15 individuals with inflammatory acne with an acne grade of III or lower were asked to volunteer for the study. They were split into 3 groups. Each group was asked to use a different formulation (a cream base, gel base and wet applicator formulation) each week. After each week, the individuals returned to fill out a questionnaire evaluating the formulation they used that week. They were also examined by the clinician for any possible side effects, and given the next formulation to use for the following week. The trial was 3 weeks long, and after using all 3 formulations the individuals were asked to fill out a final questionnaire evaluating all 3 formulations. The clinician was also asked to fill out a questionnaire giving his/her opinion on the formulations. Results: The results did not give conclusive evidence of one particular formulation being favored above all the others. All the formulations performed more or less equally as well. According to the final questionnaire, 6 out of the 15 individuals were most satisfied with the wet applicator, 4 out of 15 preferred the cream base and 5 out of 15 preferred the gel base. 5 out of 15 individuals were least satisfied with the wet applicator, 3 out of 15 with the cream base, and 7 out of 15 were least satisfied with the gel. While there was no conclusive indication for one particular formulation, there were some common complaints or observations by individuals about each formulation. Most individuals said the wet applicator had an initial burning sensation to the skin upon application, but it disappeared a few seconds after application. Many individuals said they felt the cream base was oily and made the skin appear oily after application. The gel base was said to smell the worst, along with the wet applicator, while the cream smelt the least. A few individuals complained that the gel left a residue on the skin. Conclusion: While the study did not give a clear indication of one particular formulation that was preferred by individuals, it did produce interesting results that can be used to make some of the formulations more favourable. In the main trial, further investigation will be done to optimize the formulation. / Dissertation (MSc)--University of Pretoria, 2010. / Pharmacology / unrestricted

Humic substances, such as the closely related humic and fulvic acids are ubiquitous, naturally occurring organic macromolecules of complex but undefined structure. These compounds are known complexing agents due to their supramolecular like structures and are capable of binding a wide variety of compounds. Numerous studies have confirmed that humic and fulvic acids exhibit diverse medicinal and therapeutic properties. For this reason, alternative or “natural” medicinal preparations rich in these substances are being self-administered, often concomitantly with conventional drugs. The possibility exists that these humic substances, found in the alternative medicinal products, may result in drug-drug interactions and bind to simultaneously ingested drugs. Complex formation may affect absorption and alter overall bioavailability. Changes in these parameters may lead to reduced therapeutic effect or toxic side effects of prescribed drugs in patients. Similarly, these humic substances may bind to and alter the uptake of ingested nutrients, such as vitamins and minerals, obtained from food sources as well as dietary supplements. Changes in absorption may result in a loss of proper physiological functioning in the body or in unwanted effects of overdose. This study investigated the effect of fulvic and humic acids on the absorption of commonly administered classes of drugs, vitamins and minerals using the everted mouse gut model that was successfully used to assess the membrane transport of the test compounds. This model made use of everted segments of excised intestinal tissue placed in Krebs Ringer Buffer (pH7.4), where physiological functioning of the tissue is maintained for up to two hours after excision. The amount of test compound which crossed through the intestinal membrane without and in the presence of each humic substance was quantified using LC-MS/MS methods developed for each of the drugs and vitamins, and ICP-MS, in the case of the minerals. The amount of test compound absorbed alone was compared to the amount absorbed when in the presence of each humic substance. Changes in the uptake, for each test compound was noted, the extent of the absorption increase or decrease was compound specific. The changes in absorption observed could be attributed to changes in compound solubility and mechanism of transport across the intestinal membrane once in complex. Drugs and vitamins were seen to be more prone to decreases in absorption in the presence of the humic substances, whereas the majority of the minerals showed significantly increased absorption. Binding of the minerals to the humic substances through chelation, and not complex formation, could have a greater effect on compound solubility. Health care professionals, as well as individuals ingesting these and other substances concurrently, should be aware of the potential effects on absorption that may occur due to drug-drug interactions in order to avoid a loss of therapeutic/physiological activity or negative toxic symptoms. / Dissertation (MSc)--University of Pretoria, 2015. / tm2015 / Pharmacology / MSc / Unrestricted

Magister Chirurgiae Dentium - MChD (Oral Medicine and Periodontics) / The aim of this study was to assess whether a mouthwash containing carbohydrate derived fulvic acid, is effective in reducing the salivary microbial count pre-operatively. Endeavours have been made to reduce the risk of infection, bacteraemia and cross-contamination during dental procedures by the application of topical antimicrobial agents. To date chlorhexidine is the most widely evaluated and efficacious agent against oral biofilms but there have been reports of adverse effects ranging from contact dermatitis to severe anaphylactic shock. A new mouth rinse containing carbohydrate derived fulvic acid are reported to have broad spectrum antimicrobial activity against specific oral microbes and Candida albicans with no side effects.

Notre équipe a récemment décrit la synthèse de nouveaux iminosucres de type indolizidines et quinolizidines, qui se sont avérés être de puissants inhibiteurs sélectifs d’α-glucosidases (IC50 nanomolaires). Ces molécules, de structure originale, ont la particularité de posséder un centre quaternaire en jonction de cycles et une configuration D-gluco. Dans le but de mieux comprendre le mode d’interaction de ces molécules avec les glycosidases, nous nous sommes intéressés à la synthèse de leurs analogues comportant un motif aziridine, inclus dans un squelette 1 azabicyclo[4.1.0]heptane.L’approche synthétique que nous avons choisie pour accéder aux aziridinyl iminosucres implique une cycloaddition 1,3-dipolaire régio- et stéréoselective de cétonitrones dérivées de sucres avec des alcynes pour former des isoxazolines et un réarrangement de Baldwin stéréosélectif en 2 acylaziridines. Pour les acylaziridines polybenzylées la conversion en aziridinyl iminosucres a été effectuée par réduction diastéréosélective de leur fonction cétone et déprotection dans des conditions réductrices de Birch. Pour les acylaziridines polyacétylées les iminosucres finaux ont été obtenus par réduction en présence d’hydrures métalliques.Grâce à cette stratégie de synthèse originale, efficace, et économique en atomes, nous avons préparés 7 aziridinyl iminosucres, et 5 isoxazolines polyhydroxylées. Tous ces nouveaux iminosucres ont été évalués comme inhibiteurs de glycosidases, et se sont avérées être des inhibiteurs moyens (IC50 micromolaires) mais sélectifs des α-glucosidases. L’obtention de complexes cristallins avec une α-glucosidase bactérienne a permis de montrer par cristallographie leur mode d’interaction avec cette enzyme, à l’échelle moléculaire. / Our team has recently described the synthesis of new indolizidine and quinolizidine iminosugars, which revealed to be potent and selective α-glucosidase inhibitors (nanomolar IC50). These original molecules exhibit a quaternary center at the ring junction and a D-gluco configuration. With the aim to define the mode of interaction of these molecules with glycosidases, we engaged in the synthesis of analogues containing an aziridine moiety included in a 1-azabicyclo[4.1.0]heptane scaffold.Our synthetic approach towards aziridinyl iminosugars involves a stereoselective 1,3-dipolar cycloaddition between carbohydrate-derived cyclic ketonitrones and alkynes, and a stereoselective Baldwin rearrangement into 2-acylaziridines. The latter (if polybenzylated) were converted into aziridinyl iminosugars through diastereoselective reduction of their ketone function and deprotection under Birch conditions. In the case of polyacetylated acylaziridines, the final iminosugars were obtained by reduction with hydrides.Using this strategy, we have prepared 7 aziridinyl iminosugars, and 5 polyhydroxylated isoxazolines. All these new iminosugars were evaluated as glycosidase inhibitors, and they revealed to be modest (micromolar IC50) but selective inhibitors of α-glucosidases. Their complexes with a crystalline bacterial α-glucosidase allowed crystallographic elucidation of their mode of interaction with this enzyme at the molecular level.