Extraction and isolation of alkaloids from selected plants of family Amaryllidaceae in order to study their biological activity. For the isolation of the alkaloids will be used conventional chromatographic methods such as column chromatography, flash chromatography, preparative thin-layer chromatography, preparative HPLC. Isolated substances will be identified by using spectroscopic methods and will be subjected to screening for testing their biological activities at the Department of Pharmaceutical Botany (inhibition of AChE, BuChE, POP, GSK-3β) and in cooperation with national and foreign institutions (BACE-1, cytotoxicity, antimicrobial activity, antimalarial activity and others). The active substance will be subjected to more detailed biological tests (e.g. in the case of inhibition cholinestrases will be studied type of inhibition, transfer through BBB, etc.).