Carbonyl and oxidative stress augment the development of diabetic complications. We evaluated the cytoprotectiveness of walnut and hazelnut extracts and catechins for decreasing cytotoxicity, lipid peroxidation, reactive oxygen species (ROS) formation, and protein carbonylation in cell death models of carbonyl and oxidative stress. Polar extracts (methanol or water) showed better cytoprotection than the non-polar (ethyl acetate) nut extracts against hydroperoxide-induced hepatocyte cell death and oxidative stress markers. Catechin flavonoids found in plants, including walnuts and hazelnuts, prevented serum albumin carbonylation in a carbonyl stress model (using glyoxal or methylglyoxal). Hepatocyte protein carbonylation and cell death were prevented and UV spectra data suggested a catechin:methylglyoxal adduct was formed. We conclude that (a) bioactive nut constituents in polar extracts were more protective than non-polar extracts against oxidative stress, and (b) catechins were effective under physiological temperature and pH, at preventing dicarbonyl induced cytotoxicity likely by trapping dicarbonyls or reversing early stage carbonylation.

Abstract Peptide surfactants developed in the Centre for Biomolecular Engineering at The University of Queensland are engineered to combine the advantages of traditional surfactants with biodegradability, biocompatibility, formation of a mechanically strong interfacial cohesive network, and reversible stimuli-responsiveness. In this project, the potential of peptide-stabilised emulsions as delivery systems for small interfering RNA (siRNA) was explored. In recent years, the potential of siRNA as a new class of therapeutics has attracted great attention. The ubiquitous nature of RNA interference (RNAi) implies that siRNA can be used to silence any disease-causing gene to treat any disease. The hurdle that needs to be overcome to turn siRNA therapy into clinical reality is its delivery into the cytosol, where gene silencing by siRNA occurs. Although numerous systems have been developed for the delivery of siRNA, safety and efficiency are major concerns associated with current formulations. Therefore this project aimed to prepare a stable peptide emulsion formulation and to conduct initial tests of its ability to deliver siRNA in vitro. The human tumour suppressor gene p53 and the human breast cancer MCF-7 cell line were used as the model gene and model cell line, respectively. The commercially available lipid-based transfection reagent Lipofectamine™ 2000 was used as the benchmark control. Sonication and membrane extrusion were used to formulate emulsions with droplet size (d=120 nm) suitable for intravenous applications using peptide surfactant in the presence of Zn(II). Although these peptide emulsions are stable by themselves and in bovine serum, emulsion stability was found to be strongly affected by the presence of salt, EDTA, and proteins. The instability of AM1 emulsion in cell culture media has been a concern when it was subjected to in vitro cell culture tests. AM1-stabilised emulsion droplets were shown to be taken up by MCF-7 cells. However, siRNA when coupled with AM1 emulsion was not delivered into cells. Cytotoxicity studies showed that peptide surfactants did not exhibit high-level toxicity to CHO cells at the tested concentrations (0.25-2 mg mL-1). AM1 peptide-stabilised emulsions were mildly toxic to CHO cells but no toxicity was observed with MCF-7 cells. Future work could include evaluation of peptide emulsion-siRNA complex formation, and exploring the effects of different cell culture media compositions on emulsion stability and their relation to cytotoxicity.

Actinomycetes and fungi were successfully isolated from both New Zealand and Malaysian marine invertebrates and classified as facultatively marine based on their ability to grow on both sea water and non-sea water media. Most of the extracts obtained from selected isolates were cytotoxic. A clear preference of the actinomycetes for solid-state fermentation was observed, however, for fungi no significant preference was seen. Three isolates of Streptomyces spp., four Penicillium spp. and two Paecilomyces spp. whose extracts showed good cytotoxicity were selected for further investigation. A small-scale extract obtained from a solid culture of Streptomyces sp. (LA3L2) showed good cytotoxicity and a new cytotoxic metabolite was isolated from a large-scale extract of Streptomyces sp. (LA3L2). This metabolite was characterized as S-methyl 2,4-dihydroxy-6-isopropyl-3,5-dimethylbenzothioate (5.15) and is only the third compound reported to contain the S-methyl benzothioate group. Two known compounds, montagnetol (5.16) and erythrin (5.18), were isolated from a further large-scale cultivation of Streptomyces sp. (LA3L2) and is the first reported actinomycete to produce these lichen-related compounds. In addition, two known inactive metabolites (bohemamine (5.1) and bohemamine B (5.2)) were identified from the small-scale extract. Streptomyces sp. (LA3L2) was also investigated for the effect of temperature and salinity on growth and cytotoxicity and shown to produce bohemamine only at 20 - 28℃ and 4% sea salt concentration on solid media. This isolate gave a low yield of active metabolite under all conditions. Small-scale extracts of two other Streptomyces spp. yielded three known cytotoxic metabolites. These were thiazostatin B (7.14) from Streptomyces sp. (LA5L4) and chromomycin A2 (7.1), chromomycin A3 (7.2) and chromomycin 02-3D (7.3) from Streptomyces sp. (LA3L1). All four Penicillium spp. produced known metabolites. Penicillium sp. (LY1L5) yielded two known metabolites, cycloaspeptide A (7.4) and α-cyclopiazonic acid (7.5). α-Cyclopiazonic acid (7.5) and three other known metabolites (roquefortine A (7.6), cyclopeptin (7.7) and viridicatin (7.8)) were isolated from Penicillum sp. (KK3T23). Penicillium sp. (KK3T8) produced brefeldin A (7.10), while mycophenolic acid (7.12) and brevianamide A (7.11) were produced by Penicillium sp. (KK4T14b). The effect of salinity on growth and cytotoxicity was investigated for the two Penicillium isolates producing the cytotoxic metabolite, α-cyclopiazonic acid (7.5). Saline conditions were not required for growth but metabolite production differed between the two isolates with respect to salinity. Isolate LY1L5 required saline conditions for α-cyclopiazonic production whereas isolate KK3T23 produced the metabolite under non-saline conditions and in concentrations of sea salt up to 6%. Three known compounds, indole-3-carboxylic acid (7.15), indole-3-carboxylate (7.17) and 5-carboxymellein (7.16) were identified from Paecilomyces sp. (PR5L9). Investigation of a small-scale extract obtained from a solid culture of another Paecilomyces sp. (PR10T2) resulted in the isolation and characterization of a unique structure of a symmetrical cyclic depsipeptide, epi-angolide (NAM 6-1). NAM 6-1 was considered as a new compound based on four homoisomeric configurations (A1, A2, A3 and A4). The value of dereplication procedures with respect to the rapid identification of metabolites and enhancement of in-house metabolite libraries is discussed. Structural elucidation of nine known metabolites (7.1, 7.2, 7.3, 7.5, 7.6, 7.7, 7.8, 7.10 and 7.11) was greatly aided by the in-house dereplication techniques using LC-MS-UV and AntiMarin database. A significant advantage was gained by the use of the CapNMR which enabled NMR characterization of very small quantities of metabolites (<20 µg). Approximately <5 µg of materials were required to perform 1D proton NMR experiments for the dereplication of seven known compounds; bohemamine (5.1), bohemamine B (5.2), thiazostatin B (7.14), indole-3-carboxylate (7.17) and 5-carboxymellein (7.16). Approximately 20 µg of materials were needed to acquire 1D and 2D (HSQC, HMBC and NOE) NMR spectra for structural elucidation of the new metabolite, S-methyl 2,4-dihydroxy-6-isopropyl-3,5-dimethylbenzothioate (5.15). Some 8 µg of materials were sufficient to perform 1D and 2D (COSY, HSQC and HMBC) NMR experiments for complete structural characterization of two known metabolites, montagnetol (5.16) and erythrin (5.18). Approximately 10 µg of materials were needed to acquire 1D and 2D NMR (COSY, HSQC and HMBC) experiments for structural elucidation of the new compound, epi-angolide NAM 6-1 (A1, A2, A3 and A4). Rapid identification of known fungal metabolites enabled the in-house HPLC-UV/Rt library to be enhanced by eight metabolites (7.5, 7.6, 7.7, 7.8, 7.10, 7.11, 7.17 and 7.16). An HPLC-UV/Rt library for actinomycete metabolites was successfully established with the insertion of eight known metabolites (5.1, 5.2, 5.16, 5.18, 7.1, 7.2, 7.3 and 7.14).

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Thesis (Ph.D.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Immunology, Department of Medical Microbiology and Immunology. Title from pdf file main screen (viewed on September 3, 2009). Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 108-129).

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 127-148).

Σκοπός της παρούσας μελέτης είναι η εκτίμηση της συσχέτισης ανάμεσα στην κυτταροτοξικότητα και την μείωση της ακεραιότητας λιποσωμικών μεμβρανών που προκαλούνται από έκδοχα. Εάν υπάρχει, μπορεί να προταθεί η χρήση των λιποσωμάτων ως in vitro τεχνική για την εκτίμηση της κυτταρο-τοξικότητας εκδόχων. Μελετήθηκε η κυτταροτοξικότητα σε 4 κυτταρικές σειρές ( A549, PC3, MDA-MB, MCF-7 ) και η επίδραση στην ακεραιότητα λιποσωμάτων των παρακάτω εκδόχων που χρησιμοποιούνται σε σκευάσματα τοπικής χορήγησης: Labrafac Hydro, Labrafac CC, Transcutol, Cremofor, DL- Lactic acid και Capmul σε συγκεντρώσεις 1% και 10% (v/v) Για την μέτρηση της κυτταροτοξικότητας (στις 6 και 24 ώρες επώασης) χρησιμοποιήθηκε η μέθοδος του MTT (Thiazolyl Blue Tetrazolium Bromide) ενώ για την εκτίμηση της μεμβρανικής ακεραιότητας λιποσωμάτων [χρησιμοποιήθηκαν MLV (πολυστοιβαδιακά) και SUV (μικρά μονοστοιβαδιακά) λιποσώματα, με διάφορες λιπιδικές συστάσεις [PC (φωσφατιδυλοχολίνη), HPC (υδρογονωμένη φωσφατιδυλοχολίνη) και DSPC( διστεαρουλο φωσφατιδυλοχολίνη) με ή χωρίς Chol (χοληστερόλη)] μετρήθηκε η διαφυγή της εγκλωβισμένης στα λιποσώματα καλσεΐνης. Τα πειραματικά αποτελέσματα, έδειξαν ότι η επιβίωση-πολλαπλασιασμός των κυττάρων επηρεάζεται λιγότερο ή περισσότερο από τα έκδοχα: Labrafac Hydro (1% και 10%), Transcutol (10%), Cremofor (1% και 10%), Capmul (1% και 10%) και Lactic acid (1% και 10%) ενώ πολύ λιγότερο από τα έκδοχα Labrafac CC(1% και 10%) καθώς και από το Transcutol 1%. Σε ότι αναφορά την ακεραιότητα των λιποσωμάτων ( έως 24 ώρες επώασης) τα έκδοχα Cremofor, Labrafac, Capmul, Lactic acid και Labrafac hydro επηρεάζουν όλες τις λιπιδικές συστάσεις και τύπους λιποσωμάτων που μελετήθηκαν, ενώ τα έκδοχα Transcutol και Labrafac CC επηρεάζουν πολύ λιγότερο τις πιο ρευστές λιπιδικές μεμβράνες, και σχεδόν καθόλου τις σκληρές. Φαίνεται ότι είναι πιθανή η συσχέτιση των δύο σειρών αποτελεσμάτων. / The aim of this thesis is to study if a correlation may exist between the cytotoxicity of excipients and their effect on the integrity of liposomal membranes. If such a correlation exists perhaps the effect on liposome integrity may be used as an in vitro system to predict excipient cytotoxicity. Methods: The cell toxicity in four cell lines ( A549, PC3, MDA-MB, MCF-7 ) and the influence on liposome integrity of several commonly used excipients was studied. The following excipients which are used in topical formulations were studied: Labrafac Hydro, Labrafac CC, Transcutol, Cremofor, DL- Lactic acid and Capmul at concentrations of 1% and 10% (v/v). For the measurement of cell toxicity (6 and 24 hours of incubation) the MTT-assay (Thiazolyl Blue Tetrazolium Bromide) was used, whereas for the evaluation of the liposome membrane integrity MLV (MultiLaminar Vesicles) and SUV (Small Unilaminar Vesicles) liposomes with different lipid compositions [PC (phosphatidyl choline), HPC (hydrogenated phospatidyl choline) and DSPC (distearoylphosphatidylcholine) with or without Chol (cholesterol)] were prepared and the escape of the calcein encapsulated in the liposomes was measured at different time points during their incubation in presence of the excipients. Results: The experimental results showed that the cell survival-proliferation is influenced more or less by the following excipients (in increasing effect order): Labrafac Hydro (1% and 10%), Transcutol (10%), Cremofor (1% and 10%), Capmul (1% and 10%) and Lactic acid (1% and 10%) while the effect of Labrafac CC(1% and 10%) as well as Transcutol 1%, is minimal. As far as the integrity of the liposomes (up to 24 hours of incubation) is concerned, the excipients Cremofor, Labrafac, Capmul, Lactic acid and Labrafac hydro affect all the lipidic compositions and types of liposomes that were studied, whereas the excipients Transcutol and Labrafac CC influenced only minimally the more liquid membranes and had no effect on the more rigid lipid compositions. It seems that a correlation between the two series of results is possible.

Οι πολυφαινόλες είναι μια κατηγορία οργανικών χημικών ουσιών, που χαρακτηρίζονται από την παρουσία ενός ή περισσότερων υδροξυλίων, συνδεδεμένων με έναν ή περισσότερους αρωματικούς ή ετεροκυκλικούς δακτυλίους φαινόλης. Το ταννικό οξύ (ΤΑ), μια ειδική εμπορική μορφή της τανίνης, χρησιμοποιείται ευρέως στη βιομηχανία και αποτελεί μία από τις κυριότερες ουσίες των βιομηχανικών λυμάτων που διοχετεύονται στα υδάτινα οικοσυστήματα και στο έδαφος. Παρόλο το γεγονός ότι οι πολυφαινόλες δρουν αντιοξειδωτικά στα κύτταρα, η ισορροπία μεταξύ της αντιοξειδωτικής και της οξειδωτικής δράσης τους είναι υπό διερεύνηση. Η παρούσα μελέτη διερευνά τις αντιοξειδωτικές και οξειδωτικές επιπτώσεις του ταννικού οξέος σε αιμοκύτταρα του μυδιού Mytilus galloprovincialis, παρουσία τοξικών συγκεντρώσεων καδμίου. Συγκεκριμένα, αιμοκύτταρα που εκτέθηκαν σε διαφορετικές συγκεντρώσεις ΤΑ (1, 10, 20, 40 και 60 μΜ) για 1 h, έδειξαν σημαντική μείωση της βιωσιμότητάς τους, μόνο σε συγκεντρώσεις ΤΑ μεγαλύτερες από 40 μΜ. Παράλληλα, αιμοκύτταρα που εκτέθηκαν σε μικρομοριακές συγκεντρώσεις του μετάλλου (50 και 100 μΜ) έδειξαν σημαντική μείωση της βιωσιμότητάς τους. Προκειμένου να προσδιορίσουμε την αντιοξειδωτική ή οξειδωτική ικανότητα του ΤΑ, αιμοκύτταρα που είχαν προηγουμένως προ-επωαστεί σε διαφορετικές συγκεντρώσεις ΤΑ για 15 min, εκτέθηκαν σε μικρομοριακές συγκεντρώσεις του μετάλλου. Σύμφωνα με τα αποτελέσματά μας, κύτταρα που είχαν προ-επωαστεί σε συγκεντρώσεις ΤΑ 1- 40 μΜ, έδειξαν σημαντική αναστολή των οξειδωτικών επιπτώσεων του μετάλλου (παραγωγή σουπεροξειδικών ανιόντων/∙O2 −, οξειδίων του αζώτου/ ΝΟ, και προϊόντων λιπιδικής υπεροξείδωσης/ επίπεδα μηλονικής διαλδεϋδης), όσο και της ικανότητάς του να μειώνει τη βιωσιμότητα των κυττάρων, συγκριτικά με τις τιμές που μετρήθηκαν σε κύτταρα που εκτέθηκαν μόνο στο μέταλλο. Αντίθετα, σε κύτταρα που προ-επωάστηκαν σε ΤΑ 60 μΜ, πριν την έκθεσή τους στο μέταλλο, το ΤΑ εμφανίστηκε να δρα συνεργατικά με το μέταλλο. Τα αποτελέσματα της παρούσας μελέτης οδηγούν στο συμπέρασμα ότι το ΤΑ σε μικρομοριακές συγκεντρώσεις 1-40 μΜ μπορεί να δράσει ως ένας ισχυρός αντιοξειδωτικός παράγοντας, ενώ σε υψηλότερες συγκεντρώσεις μπορεί να προκαλέσει οξειδωτικές επιπτώσεις, ανάλογες με αυτές που προκύπτουν από ισχυρούς οξειδωτικούς παράγοντες, όπως τα κάδμιο. / Polyphenols are well-known organic substances, mainly characterized by the presence of one or more hydroxyl groups on one or more aromatic or heterocyclic phenol rings. Tannic acid (TA), a specific commercial form of tannin is a natural polyphenol, widely used in food, pharmaceutical, leather and chemical industry. It is one of the main organic compounds of industrial effluents discharged into aquatic ecosystems and soil, causing environmental pollution. Despite the fact that a lot of studies reported that polyphenols could act as antioxidants in different cells, the balance between their antioxidant and pro-oxidant properties remains still unclear. According to the later, the present study investigates the antioxidant and pro-oxidant potency of TA in haemocytes of mussel Mytilus galloprovincialis in the presence or the absence of micromolar concentrations of cadmium (Cd). Specifically, haemocytes exposed to different concentrations of TA (1, 10, 20, 40 and 60 μΜ) for 1 h, showed a significant reduction of their viability, only in concentrations higher than 40 μΜ. Furthermore, cells exposed to micromolar concentrations of Cd (50 and 100 μΜ), showed significantly increased levels of cell death, compared to those observed in control cells. In order to investigate the antioxidant or pro-oxidant ability of TA, haemocytes pre-treated for 15 min with different concentrations of TA were exposed to micromolar concentrations of the metal. According to the results, cells pre-treated with TA 1-40 μΜ, showed a significant attenuation of Cd induced effects, such as the production of superoxide (∙O2 −) and nitric oxides (NO), MDA content as well as cell death, compared to those occurred in the presence of the metal alone. On the contrary, in cells pre-treated with TA 60 μΜ before their exposure to the metal, TA seemed to act synergistically with the metal. The results of the present study could lead to the suggestion that TA in concentrations ranged within 1 and 40 μΜ could act as a major antioxidant factor, whereas in higher concentrations TA could cause oxidant effects, similar with those caused by well-known pro-oxidants, such as cadmium.

Made available in DSpace on 2015-05-14T12:59:23Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1655231 bytes, checksum: 254c31110cb1231f1b493b372fc7eb41 (MD5) Previous issue date: 2009-06-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Lectins constitute a class of glycoproteins which are capable of binding carbohydrates selectively and reversibly, distinguishing small structural differences in complex oligosaccharides. Some studies have shown that binding of lectins to carbohydrate surface of normal and tumor cells leads to various biological effects such as, cell proliferation in normal lymphocytes and apoptosis in tumor cells. This study investigated the assessment of cytotoxic lectins of legumes Canavalia ensiformis (ConA), Canavalia brasiliensis (Conbr) and Cratylia floribunda (CFL) in normal, mouse peritoneal macrophage, and tumor cells. Initially the cytotoxic activity of the lectins was evaluated by reduction of tetrazolium (MTT) salt assay and measured the content of nucleic acids (CAN). ConA, Conbr and CFL not decreased the viability of peritoneal macrophages, but showed to be cytotoxic for J774, MCF-7, Molt-4 and HL-60 lineages. The MTT assay was more sensitive to the effects of lectins on cell viability and ConA was the most cytotoxic, followed by Conbr and CFL. The IC50 values ranged from around 10, 20 and 45μg/mL at ConA, Conbr and CFL respectively. The genotoxic potential of lectins was also evaluated using the comet assay, showing that proteins had a high rate of lesions in DNA from MCF-7, Molt-4 and H-60 cells, reaching a damage frequency exceeding 70% in concentration of 50 μg/mL for all lectins. The lectins caused morphological changes as assessed by differential staining with ethidium bromide and acridine orange, characteristic of apoptosis, and necrosis can be observed in higher lectin concentrations in tumor cell lines. In tests that evaluated the apoptosis, ConA, Conbr and CFL caused internucleossomal fragmentation, loss of membrane integrity which is characteristic of late apoptosis or necrosis, and mitochondrial depolarization. It was concluded that ConA, Conbr and CFL exhibited cytotoxicity to tumor cells causing cell death by apoptosis, therefore these proteins can be considered as a class of molecules with antitumor potential. / Lectinas constituem uma classe de glicoproteínas que ligam-se reversivelmente e seletivamente à carboidratos, sendo capazes de distinguir pequenas diferenças estruturais em oligossacarídeos complexos. Estudos têm mostrado que a ligação de lectinas a carboidratos de superfície de células normais e tumorais provoca vários efeitos biológicos, tais como, proliferação celular em linfócitos normais e apoptose em células tumorais. Neste trabalho, foi investigado a citotoxicidade das lectinas de plantas Canavalia ensiformis (ConA), Canavalia brasiliensis (Conbr) e Cratylia floribunda (CFL), sobre linhagens de células normais e tumorais. Inicialmente, a atividade citotóxica das lectinas foi avaliada pelos ensaios de redução do sal de tetrazólio (MTT) e medida do conteúdo de ácidos nucléicos (CAN). As lectinas ConA, Conbr e CFL não diminuíram a viabilidade de células normais (macrófagos peritoneais), no entanto, mostraram-se citotóxicas para as linhagens tumorais J774, MCF-7, MOLT-4 e HL-60. O ensaio de MTT foi o mais sensível aos efeitos das lectinas sobre a viabilidade celular do que o ensaio de CAN, sendo ConA a lectina mais citotóxica, seguida de Conbr e CFL. Os valores de CI50 variaram em torno de 10, 20 e 45μg/mL, para ConA, Conbr e CFL repectivamente. O potencial genotóxico das lectinas também foi avaliado usando o teste do cometa, mostrando que essas proteínas produziram alto índice de lesões do DNA nas células MCF-7, MOLT-4 e HL-60, atingindo uma freqüência de danos superior a 70% na concentração de 50μg/mL para todas as lectinas. Nessas mesmas linhagens tumorais, as lectinas também causaram alterações morfológicas, avaliadas por coloração diferencial com brometo de etídeo e laranja de acridina, características de apoptose, sendo possível observar necrose nas concentrações mais elevadas. Nos ensaios que avaliaram apoptose, as lectinas ConA, Conbr e CFL causaram fragmentação internucleossomal e perda da integridade de membrana, nas maiores concentrações testadas e despolarização mitocondrial. Concluiu-se que as lectinas ConA, Conbr e CFL são citotóxicas para as células tumorais causando morte celular por apoptose, podendo ser consideradas como uma classe de moléculas com elevado potencial antitumoral.