Charles University Pharmaceutical Faculty in Hradec Králové Department of Pharmaceutical Botany Candidate: Bc. Martin Cymbál, DiS. Supervisor: doc. Ing. Kateřina Macáková, Ph.D. Diploma thesis 2019/2020: Interactions of alkaloids with transition metals III., pp. 86. Copper is one of the important trace elements in the body. It regulates various enzymatic pathways. This work monitors the chelating and reducing activity of isochinoline alkaloids of the family Amaryllidaceae. The alkaloids of Amaryllidaceae have a large number of effects such as analgesic, narcotic, antiarrhythmic, antihypertensive, bronchodilatory, chemotherapeutic, antiparasitic, uteretonic, locally anesthetic, mydriatic and many other significant effects. An important representative is galanthamine hydrobromide, which is therapeutically used and is an inhibitor of acetylcholinesterase. Galanthamine type alkaloids (galanthamine, galanthamine hydrobromide, chlidanthine), lycorine type (lycorine, galanthine), haemanthamine type (haemanthnamine, vittatine) and montanine type (montanine) were studied. The methodology of the work was to determine the chelating and reducing activity with the use of the hematoxylin indicator and bathocuproindisulfonic acid, at different pH or in dimethylsulfoxide. Of the alkaloids studied, galanthamine and...

Plant natural products include a diverse array of compounds that play important roles in plant metabolism and physiology. After elucidation of biosynthetic pathways and regulatory factors, it has become possible to metabolically engineer new capabilities in planta as well as successfully engineer whole pathways into microbial systems. Microbial expression systems for producing valuable plant compounds have evolved to incorporate polyculture and co-culture consortiums for carrying out robust biosynthesis strategies. This review focuses on four classes of plant secondary metabolites and the recent advances in generating useful compounds in microbial expression platforms and in plant metabolic engineering. They are the flavonoids, alkaloids, betalains, and glucosinolates.

Dehydropyrrolizidine alkaloids (DHPAs) are a large group of globally important plant-derived pro-toxins that can contaminate or are naturally present in animal feed and the human food supply as well as herbal supplements. Their bioactive metabolites are potentially hepatotoxic, pneumotoxic, genotoxic and carcinogenic. Due to the difficulty in obtaining sufficient quantities of purified DHPAs, toxicity studies have largely relied on single intraperitoneal injections in rodent models, and carcinogenicity studies have been limited to a small handful of the hundreds of isolated DHPAs. To assess the relative toxicity of structurally diverse DHPAs in a more biologically relevant manner, male California White chicks were dosed orally with 0.01, 0.04, 0.13, or 0.26 mmol of seven different DHPAs and three DHPA N-oxides kg-1 bodyweight for 7 days. DHPAs were grouped in relation to their toxicity based on clinical, serum biochemical, and histopathological evaluations as well as tissue adduct accumulation rates. Using the same model, a reduced extract from comfrey, a commonly used DHPA containing herb, was compared to its two major constituent DHPAs, intermedine and lycopsamine. Based on the same parameters, the comfrey extract was more toxic than pure lycopsamine or intermedine. Addressing the need for a more sensitive carcinogenicity model, male heterozygous p53 knockout mice were treated with riddelliine 5, 15 or 45 mg kg–1 bodyweight day-1 by oral gavage for 14 days, or given a long-term treatment of riddelliine 1 mg kg-1 bodyweight day–1 in pelleted feed for 12 months. Exposure to riddelliine increased the odds of tumor development in a dose-responsive manner (odds ratio 2.05 and Wald 95% confidence limits between 1.2 and 3.4). The most common neoplasm was hepatic hemangiosarcoma, which is consistent with previously published lifetime rodent studies. The results of this research demonstrate that the California White chick model is sensitive for comparison of DHPA toxicity, and data obtained from this research can be used to validate previous DHPA toxicity research. It also demonstrates that comfrey toxicity may have been previously underestimated. The heterozygous p53 knockout mouse model is beneficial for further investigation of comparative carcinogenesis of structurally and toxicologically different DHPAs and their N-oxides.

Pyrrolizidine alkaloids (PAs) are natural plant compounds found in hundreds of plant species worldwide and are reported to have cytotoxic, carcinogenic, antimitotic, and gentotoxic activity. PAs are metabolized by the cytochrome P450 (CYP) sytem to the pyrrole or the N-oxide form. They pyrroles are bifunctional electrophillic alkylators that bind cellular nucleophiles such as DNA and proteins and disrupt normal cell processes, including DNA replication and gene transcription, and can cause megalocytosis. The pyrroles dehyrosenecionine (DHSN) and dehydromoncrotaline (DHMO) are among the most potent PA cross-linkers and inducers of megalocytosis. DHSN and DHMO-induced cross-links in cultured normal (MDBK) and neoplastic (MCF7) cells were nalyzed by SDS-PAGE and Western blot and both were found to contain the protein actin. Actin is crucial to DNA replication and is known to be involved in cross-links induced by cis-dichlorodiammine platinum II (cistplatin), a well known cross-linking drug used for the treatment of cancer. Actin cross-linking may explain the antimitotic, megalocytotic, and anticarcinogenic effects of PAs. Since protein cross-linking is an important mode of action for PAs, we were interested in what characteristics of the protein might make it a good nucleophilic target. Thus, further research was undertaken based on the hypothesis that cysteine residues, and specifically free sulfhydryl groups, are attractive targets for the bifunctional electrophilic alkylators DHSN and DHMO. Nucleophiles were selected for their abundance in the cell, their cysteine content, and their relationship to the documented side effects of PAs. Actin, glutathione (GSH), metallothionein, topoisomerase II, and cysteine were all found to cross-link with DHSN and DHMO in vitro while methionine, with no free sulfhydryl groups, did not cross-link. Our results support the hypothesis that cysteine residues are a key characteristic of proteins that are cross-linked by PAs. The cross-links could have negative effects to the cell as in the case of binding actin or topoisomerase II to alter normal DNA processes and replication, or beneficial effects such as binding to electrophillic scavengers like GSH or metallothionine as a detoxifying mechanism. the nucleophiles we tested in vitro and found to form cross-links with DHSN and DHMO may help to explain the antimitotic carcinogenic, and anticarcinogenic effects of PAs.

京都大学 / 0048 / 新制・課程博士 / 博士(生命科学) / 甲第20780号 / 生博第386号 / 新制||生||51(附属図書館) / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 佐藤 文彦, 教授 河内 孝之, 教授 福澤 秀哉 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

Document incorrectly classified as a dissertation on title page (decision to classify as a thesis from NDSU Graduate School) / Organocatalysis is a field that has bloomed over the last decades. With the field’s promise of being able to mimic nature and afford products in a synergistic manner to traditional Lewis acid catalysis, several interesting discoveries have been made. Owing to the vastness of the field as it exists today, this document will focus on two main aspects; cinchona alkaloid (and derivatives) as used in common carbon-carbon bond forming reactions and kinetic resolution via 4-dimethyl aminopyridine-N-oxide derivative driven acylation. Kinetic resolution via organocatalysis has the potential to react one enantiomer of a racemic mixture without affecting the other. The highlight of this screening was an s factor of 9 which was produced using optimized conditions using a catalyst designated DMAPO-IV. There remains much to do in improving the system and elucidating the scope of this catalytic system this report details the efforts made thus far.

Prom the dawn of history man has searched among the natural products of his environment for substances to com- bat his ills. The most widespread of these ills, malaria, today afflicts some 300 million people each year (1). The causative parasite, a protoza, in a somber of the Plasmodium genus and is transmitted through the saliva of the female Anopheles mosquito.

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