Isolation of alkaloids of the species Geissospermum vellosii Allemão and study of their biological activity II.

Václavíková, K., Isolation of alkaloids of the species Geissospermum vellosii Allemão and study of their biological activity II., Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmacognosy, Hradec Králové 2020. The genus Geissospermum growing in South Amerika is important for phytochemistry because it contains indole alkaloids. This southamerican tree is in traditional treatment used for therapy of different diseases such as cognitive disorders, malaria or therapy of cancer. This plant was chosen for next investigation because of screening study that has shown very interesting activity against cholinesterases (IC50 AChE = 10.51 ± 3.03 μg/ml a IC50 BuChE = 0.39 ± 0.057 μg/ml). The aim of this study was to get summary extract from the stem bark, its processing, isolation of at least one pure alkaloid and definition of its structure. Thanks to chromatographic methods the alkaloid extract was separated into 16 fractions, which were processed afterwards. The isolation of alkaloids was from the fraction GV-8, which was separated by flash chromatography and following purification of isolated alkaloids by thin layer chromatography. The only pure alkaloid was isolated form this fraction (vellosimine), in which was tested the inhibition activity against human..