Progress and prospects of ergot alkaloid research

Natural Ergot Alkaloids in Ocular Pharmacotherapy: Known Molecules for Novel Nanoparticle-Based Delivery Systems

Several pharmacological properties are attributed to ergot alkaloids as a result of their antibacterial, antiproliferative, and antioxidant effects. Although known for their biomedical applications (e.g., for the treatment of glaucoma), most ergot alkaloids exhibit high toxicological risk and may even be lethal to humans and animals. Their pharmacological profile results from the structural similarity between lysergic acid-derived compounds and noradrenalin, dopamine, and serotonin neurotransmitters. To reduce their toxicological risk, while increasing their bioavailability, improved delivery systems were proposed. This review discusses the safety aspects of using ergot alkaloids in ocular pharmacology and proposes the development of lipid and polymeric nanoparticles for the topical administration of these drugs to enhance their therapeutic efficacy for the treatment of glaucoma.

Selected Fungal Natural Products with Antimicrobial Properties

Fungal natural products and their effects have been known to humankind for hundreds of years. For example, toxic ergot alkaloids produced by filamentous fungi growing on rye poisoned thousands of people and livestock throughout the Middle Ages. However, their later medicinal applications, followed by the discovery of the first class of antibiotics, penicillins and other drugs of fungal origin, such as peptidic natural products, terpenoids or polyketides, have altered the historically negative reputation of fungal "toxins". The development of new antimicrobial drugs is currently a major global challenge, mainly due to antimicrobial resistance phenomena. Therefore, the structures, biosynthesis and antimicrobial activity of selected fungal natural products are described here.

Total Synthesis of (±)-Quinagolide: A Potent D2 Receptor Agonist for the Treatment of Hyperprolactinemia

A potent dopamine (D2) receptor agonist (±)-quinagolide, which is used for the treatment of hyperprolactinemia, was synthesized using the ring closing metathesis (RCM) approach from meta-hydroxybenzaldehyde as the starting material. The key features of this synthesis are pyrolytic elimination, late-stage expedient synthesis of functionalized trans-fused tetrahydropyridine-3-carboxylates from olefin 6, via conjugate addition-elimination upon acetate 11, followed by RCM and phenyliodine bis(trifluoroacetate) (PIFA)-mediated Hofmann rearrangement of piperidine-3-carboxamide, which enables the synthesis of 3-aminopiperidine skeleton of quinagolide. For the total synthesis of natural products such as ergot alkaloids, late-stage synthesis of functionalized trans-fused tetrahydropyridine-3-carboxylates using RCM and PIFA-mediated Hofmann rearrangement of piperidine-3-carboxamide, which allows quick access to the synthetically challenging 3-aminopiperidine skeleton, are the main achievements of the present work.

Enantioselective Total Synthesis of (+)-Lysergol: A Formal anti-Carbopalladation/Heck Cascade as the Key Step

The enantioselective synthesis of (+)-lysergol was completed in 12 steps and an overall yield of 13% starting from a known literature precursor. The key step relies on a domino reaction containing a formal anti-carbopalladation, which is terminated by a β-silyl-directed Heck reaction. During this transformation, the two six-membered rings of the ergot scaffold are formed in a completely stereospecific manner.

Parallel capillary electrophoresis for the quantitative screening of fermentation broths containing natural products

Directed molecular evolution is a recursive process of controlled genetic diversification and functional screening. The success of this approach is dependent on both the quality of the genetic diversity and the ability to accurately screen a large population of individual genetic variants for those having improved function. In this paper, the application of parallel capillary electrophoresis to rapidly quantitate lovastatin production levels by Aspergillus terreus mutants is described. A parallel 96 capillary instrument analyzed 900 samples in 8 h. with a 100 mM MES at pH 5.2 running buffer. In this manner, the fermentation broths of thousands of mutated strains were efficiently and inexpensively screened for increased lovastatin production. The ability to develop high-throughput methods to both separate and quantitate the components of complex mixtures greatly facilitates the ability to apply evolutionary engineering methods to complex biological systems.

Conformational preferences for 3-piperideines: an Ab initio and molecular mechanics study

Conformational preferences in alkyl- as well as Ph-substituted 3-piperideines (1,2,3,6-tetrahydropyridines) have been characterized by ab initio and molecular mechanics calculations. A set of rules and subrules for estimation of the conformational equilibrium (in terms of preferred substituent orientation) in these systems. with differently positioned ring substituent (-s), is presented. Examples of the revision of some previous stereochemical assignments demonstrate the reliability of these rules.