Determination of physicochemical and biochemical propertiess of natural pyridine and piperidine alkaloids and their simple derivatives from the point of view of search for agents against Alzheimer's disese

1. Research project objectives/ Research hypothesis

Alzheimer’s disease (AD) is a neurodegenerative disease which is the most common cause of cognitive impairment in people above the age of 65. In connection with ongoing ageing of well-developed countries society, AD becomes growing medical, social and economical problem.

The exact mechanism lead to Alzheimer’s disease onset is unknown. β-amyloid protein aggregates are thought to be some of the most important factors in the course of AD. These aggregates, along with degenerated parts of neurons form structures call “senile plaques”, localize in brains of patients suffering from Alzheimer’s disease. This “amyloid theory” is nowadays under an intense testing as a target for new Alzheimer’s disease therapy or prevention methods. In vitro experiments conducted in the Department of Biopharmaceutics and Pharmacodynamics of Medical University of Gdansk revealed the ability of binding to β-amyloid for some pyridine and piperidine alkaloids, what is thought to be crucial for affecting the biological activity of this pathological protein.

The aim of the proposed project will be complex analysis of binding of chosen alkaloids to the β-amyloid particle based on results of certain physicochemical properties determination, molecular modeling and complete pharmacological analysis with pharmacokinetic parameters assessment along with pharmacometric evaluation of effect on cognitive skills in mice model of Alzheimer’s disease.

2. Research project methodology

Due to the complex characteristic of proposed project, experiments will require use of specific tools and research methods. The main pharmacological aim of the project is evaluation of influence of some alkaloids on cognitive skills in mice, expressed as spatial learning and memory. These parameters will be evaluated by mean of Radial Arm Maze test. This method is well known

and widely used test to evaluate cognitive skills of laboratory rodents. Besides behavioral testing, in separate experiment, pharmacokinetic properties of chosen alkaloids will be determined, with emphasis of their ability to cross blood brain barier (BBB). This experiment will require both work with laboratory animals and development of analytical method for determination of alkaloids concentration in blood and cerebrospinal fluid with use of techniques like high-performance liquid chromatography (HPLC) with UV or fluorescence detection and mass spectrometry. Chromatographic parameters will be used for evaluation of physicochemical properties (lipophilicity and polarity) of examined xenobiotics, important from the point of view of rational drug design, and especially pharmacokinetic processes (ADME – absorption, distribution, metabolism, excretion). Pharmacodynamic (PD) and pharmacokinetic (PK) parameters will be determined by the mean of PKPD modeling. In the frames of proposed project, association constants will be also confirmed by mean of ICT (isothermal titration calorimetry) method, determination of structural descriptors will be conducted by mean of computational chemistry methods and molecular modeling of binding of alkaloids with β-amyloid particle. Based on obtained experimental and theoretical results quantitative structure-activity relationships (QSAR)

analysis will be performed. Structural requirements of so called “binding site” of β-amyloid will be identified and pathways of chemical modifications of natural alkaloids’ derivatives will be proposed, what may bring the possibility of synthesis of new anti-Alzheimer’s disease drugs.

3. Expected impact of the research project on the development of science, civilization and society

Results gathered in course of proposed project will provide important data concerning pharmacological properties of tested pyridine and piperidine alkaloids as a potential agents preventing from development of amyloidoses, especially Alzheimer’s disease. This data will improve overall knowledge about mentioned class of compounds, which is mostly of ethnopharmacological-epidemiological character nowadays. Based on behavioral tests performed, new compounds with beneficial influence on cognitive skills in Alzheimer’s disease may be identified. Those compounds in turn might be a starting point (“lead compounds”) for search for new medicines useful in therapy or prophylaxis of AD. This data will be additionally supported by the results of physicochemical properties determination and computational chemistry modeling, which helps to recognize mechanism of binding of alkaloids with β-amyloid protein particle, what, besides scientific value, might be of great importance in development of new active substances with requested biopharmaceutical properties.