Boophone disticha (L.f.) Herb is one of the most widely distributed bulbous species in southern Africa. Of Africa’s many bulbous plants, it is widely known for its poisonous and medicinal properties. It is of considerable ethnobotanical interest in traditional medicine because of its hallucinogenic alkaloids and it has great potential as an ornamental due to its fan-shaped foliage and large umbel of bright pink to deep red flowers. In South Africa, many bulbous plants are used in traditional medicine which are collected from wild populations. The high demand for trade and use of such plants, that are destructively harvested, places an enormous pressure on natural populations. According to the Red List of South African Plants, the conservation status of B. disticha has been listed as ‘declining’. It is, therefore, important to develop conservation strategies for these medicinal plants, such as the development of alternative propagation methods. Micropropagation is a useful technique for rapid clonal multiplication of plant material which could alleviate the pressure on the wild plant populations, as well as potentially producing useful secondary metabolites. The in vitro induction of storage organs is especially beneficial as it can limit the loss of plants during acclimatization since bulblets are generally hardier than shoots or plantlets. Thus, the main aim of this research was to establish a micropropagation protocol which could be a valuable tool for conservation of this plant species. In addition, B. disticha plants were assessed in various ethnopharmacological assays to evaluate their medicinal properties, and a preliminary study on the population genetics was also conducted. As part of the development of a suitable micropropagation protocol, the effect of environmental and physiological factors on the initiation and growth of bulblets were investigated. These factors included the effect of various plant growth regulators, carbohydrates, temperature, photoperiod and liquid culture. Different explants (i.e. ovaries, anthers, filaments, pedicels, embryos, seeds and bulb twin-scales) were tested to determine which explants were the most suitable for subsequent experiments. Although success was limited, twin-scales proved to be the most suitable explant and it was demonstrated that activated charcoal, ascorbic acid and N6- benzyladenine were required as media supplements. Antimicrobial activity was tested between different plant parts and seasons. The plant parts (roots, leaves, outer and inner bulb scales) were extracted with a range of differing polarity solvents. These were screened for antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae, and for antifungal activity against Candida albicans. Extracts from roots of plants collected in spring and summer showed the best antimicrobial activity against B. subtilis, E. coli and K. pneumoniae, indicating that plant part and collection time do affect activity. In vitro grown bulblets also showed antimicrobial activity, demonstrating that antibacterial properties were maintained in cultured plantlets. Extracts from plants collected in summer were tested for mutagenicity using the Ames test (Salmonella/microsome assay; plate incorporation method, with or without metabolic activation). None of the extracts tested were found to induce mutations and also did not modify the effect of the mutagenic compounds (2AA with S9 and 4NQO without S9). Although the results do not indicate a mutagenic response, this does not necessarily confirm that it is not mutagenic nor carcinogenic to other bacterial strains, however, B. disticha must be used with caution, especially considering the levels of alkaloids in the plant. The two major constituent alkaloids of B. disticha were identified as buphanidrine and distichamine. In the antibacterial assay, both compounds exhibited broad-spectrum micromolarlevel activity against the two Gram-positive and two Gram-negative bacteria tested. The best MIC value, of 0.063 mg/ml, was found for bupanidrine/distichamine against S. aureus, E. coli and K. pneumonia. The isolated compounds were tested and found to be neither mutagenic nor toxic at the concentrations tested. Thus, buphanidrine and distichamine are thought to be the constituents likely responsible for the medicinal properties of the plant. To determine the level of genetic variation between different populations of B. disticha, plants were collected from six wild populations in KwaZulu-Natal, South Africa. DNA was isolated and tested for genetic variation using ten Inter Simple Sequence Repeat (ISSR) primers. The level of inter-population polymorphism ranged between 23% and 39%, showing that the populations had low genetic polymorphism. From the genetic distance results, it was found that the Midmar and Umgeni Valley populations are closely related, and these populations are similar to two sister populations. The Amatikulu and Lions River populations were similar but slightly different to the other populations. Antimicrobial assays showed minor difference in activity from the six wild populations. Although the micropropagation of B. disticha had limited success, this study did develop a successful decontamination protocol as well as determine the most useful explant and supplements. This information provides an important starting point for the development of a successful micropropagation protocol for the conservation of B. disticha. Since, B. disticha is an important medicinal plant in South Africa, this study has also deepened our understanding of the constituents that could be responsible for the medicinal properties of B. disticha and, in so doing, confirmed the value of this plant for use in traditional medicine in South Africa. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Type II polyketide synthase (PKS) produced natural products have proven to be an excellent source of pharmacologically relevant molecules due to their rich biological activities and chemical scaffolds. Type II-PKS manufactured polyketides share similar polycyclic aromatic backbones leaving their diversity to stem from various chemical additions and alterations facilitated by post-PKS tailoring enzymes. Evidence suggests that post-PKS tailoring enzymes form complexes in order to facilitate the highly orchestrated process of biosynthesis. Thus, protein-protein interactions between these enzymes must play crucial roles in their structures and functions. Despite the importance of these interactions little has been done to study them. In the mithramycin (MTM) biosynthetic pathway the Baeyer−Villiger monooxygenase (BVMO) MtmOIV and the ketoreductase MtmW form one such enzyme pair that catalyze the final two steps en route to the final product. MtmOIV oxidatively cleaves the fourth ring of the mithramycin intermediate premithramycin B (PreB) via a Baeyer−Villiger reaction, generating MTM’s characteristic tricyclic aglycone core and highly functionalized pentyl side chain at position 3. This Baeyer−Villiger reaction precedes spontaneous lactone ring opening, decarboxylation, and the final step of MTM biosynthesis, a reduction of the 4′- keto group catalyzed by the ketoreductase MtmW. Another example of co-dependent post-PKS tailoring enzymes from the gilvocarcin biosynthetic pathway is composed of GilM and GilR. These two enzymes form an unusual synergistic tailoring enzyme pair that does not function sequentially. GilM exhibits dual functionality by catalyzing the reduction of a quinone intermediate to a hydroquinone and stabilizes O-methylation and hemiacetal formation. GilM mediates its reductive catalysis through the aid of GilR that provides its covalently bound FADH(2) for the GilM reaction, through which FAD is regenerated for the next catalytic cycle. A few steps later, following glycosylation related events unique to each gilvocarcin derivative, GilR dehydrogenates the hemiacetal moiety created by GilM to establish the formation of a lactone and the final gilvocarcin chromophore. To achieve a better understanding of post-type II PKS tailoring enzymes and their protein-proteininteractions for the benefit of future combinatorial biosynthetic efforts two specific aims were devised. Specific aim 1 was to investigate the structure of MtmOIV and the role of active site residues in its catalytic mechanism. Specific aim 2 was to integrate the function of GilM and its protein-protein interactionswith GilR that lead to their synergistic activity and sharing of GilR’s bicovalently bound FAD moiety.

Several nucleoside natural product antibiotics from Streptomyces sp. and actinomycetes have recently been shown to target bacterial peptidoglycan cell wall biosynthesis by inhibiting the bacterial translocase I (MraY). The biosynthetic gene clusters for A-90289, liposidomycins and caprazamycins revealed a protein with sequence similarity to proteins annotated as α-KG:taurine dioxygenases (TauD). This enzyme (LipL) is a mononuclear, non-heme, Fe(II) dependent α-keto glutarate (α-KG) :uridine monophosphate (UMP) dioxygenase responsible for the net dephosphorylation and two electron oxidation of UMP to uridine-5’-aldehyde. The postulated reaction coordinates involving the activation of the C-5’ center in UMP and the corresponding formation of uridine-5’-aldehyde are modeled on extensive spectroscopic and structural characterizations of TauD. In this dissertation, the postulated radical mechanism for LipL involving the formation of an unstable hydroxylated intermediate is investigated via the characterization of a key product obtained from the reaction of LipL (and its homolog Cpr19) with a synthetically modified surrogate substrate where the bridging phosphoester oxygen in UMP is replaced with a 5’ C-P bond. We further validate our hypothesis by analyzing the reactions of both LipL and Cpr19 with specifically 2H1 – labeled UMP substrate and confirming the expected products via mass spectrometry. In addition, we explore substrate promiscuity of the enzymes and utilize a set of site specific mutants of Cpr19 as means of gaining better insight into the active site residues. Predictive models for Cpr19 and LipL structures are developed by the combination of experimental results and chemical logic.

<p>In South Africa, the crude aqueous extract from Hypoxis hemerocallidea is used by AIDS patients to treat opportunistic infections, such as tuberculosis. The rapid emergence of multidrug-resistant tuberculosis, and extreme drug resistant tuberculosis, in recent years, is a major threat to human health. The treatment of TB, nosocomial bacterial infections, and fungal infections is now a clinical challenge, especially in the immuno-compromised individual. There is a dire need for novel antibiotic alternatives with phytotherapies and plant-derived compounds as potentially promising alternatives. The main objective of this study was to investigate the antimycobacterial activity of Hypoxis hemerocallidea, a South African medicinal plant, using Mycobacterium smegmatis.</p>

<p>The incidence of cardiovascular diseases, including hypertension, is on the increase worldwide. Medicinal plants played an important role in the treatment of hypertension for centuries. Very few scientific studies have, however, been done to validate the use of these phytotherapies. O africana is on of the many phytotherapies that has been use indigenously for years to treat hypertension. The objectives of this study were to determine the most effective does of O africana aqueous extract which will reduce blood pressure / to determine whether chronic administration of O africana can be used to prevent and treat hypertension / to determine whether O africana exert its effects by modulation of the renin-angiotensin system.</p>

Os extratos de espécies de Passiflora (Passifloraceae), comumente empregados no tratamento de diversas doenças em regiões tropicais e subtropicais, têm se mostrado fonte em potencial de medicamentos. O uso popular de espécies vegetais pertencentes a esse gênero decorrente de suas propriedades sedativas consta a partir do século 17 na Europa. Após cerca de 200 anos, foram documentados os estudos farmacológicos iniciais com P. incarnata. No Brasil, uma espécie morfologicamente assemelhada a essa - P. edulis Sims. - tem encontrado uso como sedativo, ansiolítico, diurético e no tratamento de distúrbios gastrintestinais, embora esta espécie seja explorada comercialmente na produção de sucos concentrados. Pesquisadores têm avaliado a atividade de extratos de folhas de P. edulis no sistema nervoso central. Considerando o uso popular e a falta de trabalhos científicos avaliando a ação no sistema digestório, o extrato liofilizado preparado com as folhas e com os caules dessa espécie foi ensaiado em ratos, empregando-se solução de etanol acidificado como indutor de úlceras. A triagem fitoquímica e a avaliação da atividade antioxidante (DPPH, ORAC) foram realizadas para verificar o potencial uso dos metabólitos encontrados no extrato. O método espectrofotométrico foi empregado na análise do teor flavonoídico. As técnicas de Cromatografia Líquida de Alta eficiência (CLAE) e espectrofotometria UV/visível foram utilizadas para analisar as frações f1avonoídicas. A caracterização morfoanatômica das folhas e dos caules da espécie foi efetuada como auxiliar no controle de qualidade da droga vegetal. No modelo ensaiado, o extrato de P. edulis não mostrou atividade antiúlcera promissora. Nessa fase não se pode descartar seu uso no tratamento de úlceras gástricas. O extrato liofilizado apresentou teor flavonoídico de 1,2% e atividade antioxidante, demonstrada com os métodos empregando DPPH (EC50 de 160 &#181;g/mL) e ORAC (775,35 &#177; 36,12 &#181;mol eq Trolox/g de extrato). Na análise preliminar das frações flavonoídica foi evidenciada a predominância de flavonas. Caracteres morfoanatômicos importantes na análise da droga vegetal foram documentados. / The extracts of Passiflora spp. (Passifloraceae), commonly used in the treatment of several diseases from tropical and subtropical regions, have been proving to be a potential source for the preparation of medicines. Because of theirs sedating properties, popular use of vegetal species belonging to this genus has been found since the 17th century in Europe. Then, after 200 years, early pharmacologic studies with P. incarnata were documented. In Brazil, one species morphologically similar to this one - P. edulis Sims. - has been used as sedative, anxiolytic, diuretic and for the treatment of gastrointestinal diseases, although this species has been commercially explored in the production of concentrated juices. Researchers have been evaluating the effects of the extract of P. edulis leaves in the central nervous system. Considering its popular use and the lack of scientific research evaluating its effect in the digestive tract, the freeze-dried extract prepared with its leaves and stems was tested in rats. Acute gastric lesions were induced by acidified solution of ethanol. The phytochemical screening and the antioxidant effects evaluation (DPPH, ORAC) have been carried out in order to evaluate the potential use of metabolites found in the extract. The spectrophotometric method was applied in the analyses of flavonoids content. High Performance Liquid Chromatography (HPLC) and UV/ visible methods were used to analyze the flavonoid fractions. Morphoanatomic characterization of leaves and stems of the species was done to applied in the quality control of the crude drug. In the tested model, P. edulis extract did not show its potential gastroprotective property. At this point we can not discard its use to treat gastric ulcers. The flavonoid content quantified in the extract were 1,2%. The freeze¬dried extract presented antioxidant activity, demonstrated with DPPH (EC50 de 160&#181;g/mL) and ORAC (775,35 &#177; 36,12 &#181;mol eq Trolox/g) methods. The chemical profile of flavonoid fractions showed predominant concentration of flavones. Important morphoanatomic characters of the crude drug were documented.

Prevention of the accumulation of undesirable biological material i.e. biofouling upon a solid surface requires the use of antifouling systems. The solid surface may be a contact lens, an off shore oil rig or a living organism. When chemicals are employed as a mechanism of defense against biofouling, the agents involved are known as antifouling agents. Marine algae must protect themselves from fouling organisms and it is thought that one of the mechanisms used by these organisms is the production of secondary metabolites with an array of biological activities. In vitro studies have shown numerous compounds isolated from marine algae to possess antibacterial, antifungal and antimacrofouling activity. The aim of this study was to evaluate the secondary metabolite extracts of selected Southern African marine macro-algae as a potential source of compounds that inhibit biofilm formation and that could be used as antifouling agents. In this project, marine macro-algae were collected from various sites along the South African coastline. Their extracts were screened for antimicrobial activity against four ubiquitous microorganisms, Staphylococcus aureus, Klebsiella pneumoniae, Mycobacterium aurm and Candida albicans. Results of screening assays guided the fractionation of two Rhodophyta, Plocamium corallorhiza and Laurencia flexuosa. The algae were fractionated using silica gel column chromatography and compounds were isolated by semi-preparative normal phase HPLC. Compound characterization was performed using UV, IR and advanced one- and two-dimensional NMR (¹H, ¹³C NMR, COSY, HSQC, HMBC and NOESY) spectroscopy and mass spectrometry. Ten halogenated monoterpenes including four members of the small class of halogenated monoterpene aldehydes were isolated from extracts of P. corallorhiza. The compounds isolated included the known compounds 3,4,6,7-tetrachloro-3,7-dimethyl-1-octene; 4,6-dibromo-1, 1-dichloro-3,7 -dimethyl-2E,7 octadiene; 4,8-d ibromo-1,1,7 -trichloro-3, 7-dimethyl-2,5Eoctadiene;1 ,4,8-tribromo-3, 7 -dichloro-3,7-dimethyl-1 E,5E-octadiene; 8-bremo-6, 7-dichloro-3,7-dimethyl-octa-2E,4E-dienal; 4-Bromo-8-chloro-3,7-dimethyl-octa-2E,6E-dienal; 4,6- Dibromo-3,7-dimethyl-octa-2E,7-dienal; 2,4-dichloro-1-(2-chlorovinyl)-1-methyl-5-methylidene-cyclohexane and two new metabolites 4,8-chloro-3,7-dimethyl-2Z,4,6Z-octatrien-1-al and Compound 3.47. Methodology was developed for the chemical derivatization and mass spectrometric analysis of the aldehydic compounds, The aldehyde trapping reagent 0-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride was used to derivatize the molecules, stabilizing them and allowing for their complete characterization. From Laurencia flexuosa a new cuparene sesquiterpene 4-bremo-2-(5-hydroxy-1,2,2- trimethylcyclopent-3-enyl)-5-methylphenol was isolated along with two geometric isomers of the vinyl acetylene bromofucin , An halogenated monoterpene 3S*,4R*-1-bromo-3,4,8-trichloro-9-dichloromethyl-1-E,5-E,7-Z-octatriene was also isolated but was suspected to be a contaminant and an investigation into its biological source revealed that it originated from Plocamium suhrii. A third alga, Martensia elegans was extracted based on published reports of antimicrobial compounds in related species. A new a-alkyl malate derivative was isolated and characterized. Selected compounds isolated during the course of the study were employed in preliminary assays that tested their ability to inhibit biofilm formation by Pseudomonas aeruginosa. The halogenated monoterpenes isolated from the Plocamium species were the only active compounds. 3S*,4R*-1-bromo-3,4,S-trichloro-g-dichloromethyl-1-E,5-E,7-octatriene from P. suhrii inhibited biofilm formation through antibacterial activity on planktonic cells but could not prevent biofilm formation when employed as a film on the surface of microtitre plate wells. 1,4,8-tribromo-3,7-dichloro-3,7-dimethyl-1E,5E-octadiene and 4,6-dibromo-1,1-dichloro-3,7-dimethyl-2E,7-octadiene inhibited biofilm formation when applied as a film to the microtitre plate wells but had no significant antibacterial activity. No potential antifouling agents were identified in this project but the antimicrobial activity exhibited by the crude algal extracts was highly encouraging and a number of new research areas have been identified. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Candidate: Bc. Hana Studená Supervisor: Doc. RNDr. Jiřina Spilková, CSc. Consultant: RNDr. Anna Polášková Title of diploma thesis: Quality control of herbal drug Sambuci fructus from cultivated plants The main aim of this thesis was to verify the quality of elderberry fruits of the cultivars Sambo, Sambu, Samdal, Samyl and of the wild elderberry according to tests specified in the Czech Pharmacopoeia 2009 and the Czech Pharmaceutical Codex 1. Loss on drying, total ash, ash insoluble in hydrochloric acid were determined. Another aim of this thesis was to compare certain cultivars of elderberry according to the content of anthocyanins in different parts of the fruits. A new modification of the spectrophotometric analysis using the pH-differential method was applied and its linearity and accuracy verified. Further, stability of the samples under given conditions was studied. A loss of anthocyanins content was observed, which was lower than 10 percent. The highest amount of anthocyanins was found in the cultivars Samyl and Samdal, the lowest amount in Sambu and wild elderberry. Although the determined quantities of anthocyanins differed in various parts of the fruit, the amount of anthocyanins in exocarp was...

Two natural marine compounds, 3-bromo-4,5-dihydroxybenzaldehyde 2 and 2,3-dibromo-4,5-dihydroxybenzaldehyde 5 together with two novel derivatives, 3-bromo-5-(tert-butyl-dimethyl-silanyloxy)-4-hydroxybenzaldehyde 3 and 1-bromo-2,3-dimethoxy-5-nitrooxy-methylbenzene 9, were synthesized. Compounds 2, 3, and 5 were evaluated for their biological activity towards the inhibition of prostate cancer cell growth using staurosporine a a positive control. All three compounds have shown significant inhibition of prostate cancer cell growth. Compound 9 is yet to be evaluated.

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