Red maple (Acer rubrum), also known as swamp, water or soft maple, is endemic to eastern and central North America and was widely used as traditional medicine by the first peoples. Commercially, its well-known products include maple syrup and high-quality lumber. The potential medicinal benefits of phenolic compounds extracted from the red maple plant, such as glucitol-core containing gallotannins, include antioxidant, and antiglycation effects as well as their importance in cosmetic applications. Plant-derived proteins and peptides are important biomolecules; however to date, there is no published data on the identification of proteins/peptides from red maple leaves. Therefore, the present study focuses on the activity guided purification of proteins from red maple leaves collected in spring and fall seasons. In addition, the focus of this project was in the evaluation of maple leaves employing bottom-up proteomics and De Novo protein profiling by PEAKS Studio-X and Gene Ontology Bioinformatics. The red maple leaves were grounded, defatted in hexane and proteins extracted in 25 mM sodium phosphate buffer pH 6.5. The extracted crude proteins were recovered by precipitation in 80% ammonium sulfate. The first-dimensional chromatography of crude extracted proteins was performed on a gel filtration column (HiLoad 16/600 Superdex200). The separation of crude extract and the partially purified gel filtration fraction was conducted by reversed-phase HPLC. The crude and eluted fractions were analyzed by SDS-PAGE gel electrophoresis. The extract was screened for cytotoxicity activity on Michigan Cancer Foundation-7 breast cancer (MCF-7), M.D. Anderson Metastasis Breast (MDA-MB-231) cancer cell lines and anti-inflammatory activity on murine macrophage (RAW 264.7) cell line from American Type Culture Collection (ATCC). The drug Doxorubicin was used as a positive control whereas untreated cells as a negative control in these experiments Preliminary data revealed that active protein fractions were eluted at two different regions of gel filtration chromatography both in spring and fall leaves. Bottom-up proteomics of crude and active fractions by PEAKS Studio-X and MASCOT bioinformatics database identified over 54 proteins. The Gene Ontology Annotation classified these proteins involved in the biological processing, cellular compartment, and molecular functions.

Thesis (Ph. D.)--University of Queensland, 2003. / Includes bibliographical references.

Fifteen naphthylisoquinoline (NIQ) alkaloids including four new compounds, the 5,8'-coupled ancistroyafungines A-C, and the 5,1'-linked ancistroyafungine D, as well as eleven known NIQs were isolated from the stem bark of an unidentified Ancistrocladus (Ancistrocladaceae) liana recently discovered in the North-Central region of the Democratic Republic of the Congo. Most of the isolated alkaloids were S-configured at C-3, and possessed an oxygen function at C-6 in the isoquinoline portion, which is characteristic to the subclass of “Ancistrocladaceae-type” alkaloids. This finding was geo- and chemotaxonomically interesting since, except for one other Ancistrocladus species found in the Central Congo Basin, only Southeast Asian and East African Ancistrocladaceae are known to exclusively produce naphthylisoquinolines with these structural features. Moreover, the alkaloid pattern of this Congolese liana clearly differentiates this plant from all other Ancistrocladus taxa that have so far been botanically described, which suggests that it might represent a new species or subspecies. The new ancistroyafungines displayed strong preferential cytotoxic activities (with PC50 7.6 to 22.7 µM) towards human PANC-1 pancreatic cancer cells in nutrient-deprived medium, without showing toxicity in normal, nutrient-rich conditions. Along with the above described naphthylisoquinoline alkaloids, nine other analytes including four flavonoids: quercetin, kaempferol, hyperoside, and isoquercetin, and five lignans: justicidins A and B, 6-methoxyjusticidin A, chinensinaphthol, and retrochinensinaphthol methyl ether were isolated from Monsonia angustifolia and Monsonia glauca plants collected in South Africa. The extracts, the fractions, and compounds of M. angustifolia and M. glauca plants were screened for the first time for their Nrf2 activity. M. angustifolia sequential extracts exhibited superior Nrf2 activation with three active extracts, n-hexane, methanol, and aqueous extracts showing 169.0, 236.1, and 130.0% increase relative to the control. The methanol extract of M. angustifolia showed the strongest increase, better than that of sulforaphane (170.0%) used as positive control. Seven fractions collected from the column chromatography of the methanol extract of M. angustifolia exhibited a good Nrf2 activation with percentage increase ranging from 106.0 to 199.0% relative to the control. The isolated flavonoids from these fractions were screened for Nrf2 activity but the tests were inconclusive as the compounds may have decomposed in DMSO during the lengthy storage process, nevertheless, these compounds have been previously reported to be Nrf2 modulators. Based on this, they are in all likelihood responsible of the good activity of the methanol extracts of both Monsonia species. This study was the first to report the presence of isolated flavonoids in M. angustifolia. The isolated lignans were inactive against the human PANC-1 pancreatic cancer cell but they displayed strong to moderate activities against the HeLa cervical cancer cell. Justicidin B was the most potent compound of the isolated lignans with the IC50 value of 1.2 µM. The UPLC-MS chromatograms of the two species showed them to be different, as justicidin B was mainly found in M. glauca while justicidin A and 6-methoxyjusticidin A were predominant in M. angustifolia. To the best of our knowledge, this is the first report on the presence of justicidin B in Monsonia glauca, as well as its phytochemical properties and its bioactivities. / Thesis PhD (Chemistry))--University of Pretoria, 2019. / The Deutsche Forschungsgemeinschaft (Project Br 699/14-2; SFB 630 “Agents against Infectious Diseases”) The Excellence Scholarship Program BEBUC (www. foerderverein-uni-kinshasa.de), The South African Department of Science and Technology (DST) The National Research Foundation (NRF)/South Africa and The University of Pretoria / Chemistry / PhD (Chemistry) / Unrestricted

No description available.

Thesis (M.S.)--Youngstown State University, 2008. / Includes bibliographical references (leaves 47-50). Also available via the World Wide Web in PDF format.

Actinomycins are a class of compounds consisting of phenoxazinone-like core attached to two peptidolactone rings, denoted as α and β. A unique component of a few families—actinomycins G, Y, and Z—is a chlorinated β-ring threonine residue. Families G and Y also contained an actinomycin that possess a β-ring heterocycle (actinomycins G5 and Y5, respectively); prior to this work, no β-ring heterocycle-containing actinomycins were reported for the Z family. Unlike other actinomycin derivatives, Y5’s cytotoxicity was abolished while still maintaining some antibacterial potency. We constructed a model compound to probe the physical properties of the actinomycin core to test conditions under which heterocycle formation would occur. We also analyzed the gene clusters of these actinomycin producers for gene candidates to from this structural motif. We found the the actinomycin core aniline to have pKa values of 2.976 and 8.429 and a significant shift in UV absorption between 300-310nm when the group becomes charged. We also found cyclization conditions and no obvious gene candidates to form the β-ring heterocycle based on our gene cluster analysis. We hypothesize that the familial diversity of the actinomycin G, Y and Z familes is due to the reactivity of the phenoxazinone-like core.

Major depressive disorder affects people’s productivity and ability to function in everyday life. The disorder can be attributed to neurochemical imbalances of various neurotransmitters including but not limited to serotonin, dopamine, and norepinephrine. Conventional pharmacological treatments have focused primarily on these three neurotransmitters, and have been shown to be effective in alleviating most of the major symptoms of depression. Although these treatments are effective with most patients, they are known to have adverse side effects, causing patients to seek alternative treatments. Sceletium tortuosum, a succulent plant found in the Cape region of South Africa, has been shown to have anxiolytic effects when used recreationally. Studies have confirmed the presence of a family of alkaloids mesembrines that are present within the plant and believed to be responsible for the calming effects. Pharmacological analyses have revealed that individual members of the alkaloid family act as either serotonin reuptake inhibitors (SRI) or phosphodiesterase-4 (PDE4) inhibitors. The current study seeks to elucidate the antidepressant properties of the mesembrine alkaloids in a mouse model of depression. Isolated alkaloids were administered at a low dose (10 mg/kg) and a high dose (80 mg/kg) to BALB/c mice in the forced swim test a rodent model of behavioral despair. This was compared with paroxetine (Paxil) (1 mg/kg), a selective serotonin reuptake inhibitor with proven antidepressant efficacy, and 0.9% saline. Each trial of the forced swim test was administered for six minutes and the duration of swimming and immobility was measured. In order to assess any locomotor effects of the drug treatments, an open field exploration test was also employed one week following the forced swim task. Results from the forced swim test revealed a statistically significant reduction in the duration of immobility (behavioral despair) between the low dose of alkaloids and saline. No significant effects in immobility were found across the other drug treatment conditions (high dose mesembrine, paroxetine, and saline). Further, none of the treatment groups showed statistically significant locomotor interference effects in the open field exploration test. We conclude that the mesembrine alkaloids present in Sceletium tortuosum have antidepressant properties and may represent a suitable alternative for the treatment of major depressive disorder.

<p>Nonribosomal peptides, polyketides, and fatty acids comprise a distinct subset of microbial secondary metabolites produced by similar biosynthetic methods and exhibit broad structural diversity with a high propensity for biological activity. Dedicated studies of these specific microbial small molecules have identified numerous potent actions towards human cells with many clinical translations. Interestingly, most therapeutically used nonribosomal peptides and polyketides were discovered from soil bacteria, meanwhile, bacteria that have co-evolved within a human context, the human microbiota, have barely been explored for secondary metabolites. The central goal of this thesis is to explore the secondary metabolome of human microbiota for nonribosomal peptides and polyketides, which are hypothesized to possess biological activities significant within the human host context. Candidate organisms were chosen for their established connections to human health and evidence suggestive of secondary metabolite production. Specifically, questions about gene to molecule prediction capability, metabolite production, structural diversity, and biological activity were explored from studies of the dental caries linked Streptococcus mutans UA159, from the probiotic Lactobacillus plantarum WCFS1, and the Crohn’s disease associated Faecalibacterium prausnitzii.</p> / Master of Science (MSc)

This thesis describes studies towards the total synthesis of manzamine A (9), a marine alkaloid. Two routes are presented. The first route applied a novel palladium-catalysed arylative allene spirocyclisation cascade to the synthesis of manzamine A (9). In the first generation, a short route was developed to access the tricyclic ACE core 263a in only nine steps. The second generation applied the palladium-catalysed cascade to a similar system which utilised non-terminal allene pro-nucleophile 450 in an attempt to access a homologated derivative of the ACE core. The second route relied on a diastereoselective Michael addition between nitro-olefin 473 and 8,5-fused ring system 146 comprising rings C and E of manzamine A (9). Further elaboration of the Michael addition product enabled the synthesis of tetracyclic ABCE core precursor 464 to be carried out and preliminary investigations into ring B formation were investigated.

Gilvocarcin V (GV) belongs to the angucycline class of antibiotics that possesses remarkable anticancer and antibacterial activities with low toxicity. Gilvocarcin exhibits its light induced anticancer activity by mediating crosslinking between DNA and histone H3. When photo-activated by near-UV light, the C8 vinyl group forms a [2+2] cycloadduct with thymine residues of double stranded DNA. D-fucofuranose is considered essential for histone H3 interactions. However, the poor water solubility has rendered it difficult to develop gilvocarcin as a drug. We aim to design novel gilvocarcin analogues with improved pharmaceutical properties through chemo-enzymatic synthesis and mutasynthesis. Previous studies have characterized many biosynthetic genes encoding the gilvocarcin biosynthetic skeleton. Despite these previous findings the exact functions of many other key genes are yet to be fully understood. Prior gene inactivation and cross-feeding experiments have revealed that the first isolable tetracyclic aromatic product undergoes a series of steps involving C–C bond cleavage followed by two O-methylations, a penultimate C-glycosylation and final lactone formation in order to fully develop the gilvocarcin structure. To provide a deeper understanding of these complex biochemical transformations, three specific aims were devised: 1) synthesis of the proposed intermediate and in vitro enzyme reactions revealed GilMT and GilM’s roles in gilvocaric biosynthesis; 2) utilizing in vitro studies the enzyme responsible for the C–C bond cleavage and its substrate were determined; 3) a small series of structural analogues of the intermediate from the gilvocarcin pathway was generated via chemical synthesis and fed to the mixture of the enzymes, GilMT and GilM. These reaction mixtures were then analyzed to establish the diversity of substrates tolerated by the enzymes.