Pharmacognostical studies on narcissus tazetta l. subsp. tazetta l. growing around Mugla province

Amaryllidaceae alkaloids are a group of secondary metabolites which have therapeutic potential for the treatment of various diseases and have been deeply searched in terms of bioactivity. The genus Narcissus, belonging to the Amaryllidaceae family, evaluated as a valuable source of natural products, has been investigated for its alkaloidal profile in terms of its species and subspecies. This thesis consists of phytochemical studies on bulbs and aerial parts of Narcissus tazetta subsp. tazetta L. collected from its natural habitat in Mugla/Turkey as there have been no study carried out on this subspecies. Quality-control studies including, loss on drying, total ash, sulphated ash and hydrochloric acid-insoluble ash have been performed according to European Pharmacopoeia on drug specimens. The results were given as percentage values. Additionally, total alkaloidal contents of the drug specimens were determined by a titrimetric method. Galanthamine and lycorine, biologically important alkaloids of Amaryllidaceae family, in two different drug specimens prepared from Narcissus tazetta subsp. tazetta L, were qualitatively and quantitatively investigated using high pressure liquid chromatography (HPLC). Furthermore, capillary gas chromatography-mass spectrometry (GC-MS) was used to determine the alkaloidal profile of two different drug specimens. As a result, 23 alkaloids were detected in Narcissus tazetta subsp. tazetta. In the studies, where isolation and structure elucidation investigations were carried out, total alkaloidal extract, prepared from powdered whole plant material dried at room temperature, was fractionated by column chromatography. The obtained fractions have been purified by different methods such as preparative column chromatography, preparative thin layer chromatography and crystallization. The structures of the obtained compounds were elucidated by modern spectroscopic methods (1D, 2D NMR, MS). As a result of these studies, the Amaryllidaceae alkaloids, (-)-lycorine, (-)-pseudolycorine, (-)-9-O-methylpseudolycorine, (+)-11-hydroxygalanthine, (-)-narcissidine from the lycorine subgroup; (+)-9-O-demethyl-2-α-hydroxyhomolycorine from the homolycorine subgroup; (-)-pancratinine-C from the montanine subgroup and (-)-galanthamine from the galanthamine subgroup were isolated from Narcissus tazetta subsp. tazetta. All compounds are reported for the first time in the title subspecies collected from Turkey. Acetylcholinesterase ve butyrylcholinesterase inhibitory activities of isolated compounds which are not studied before, were determined by using a microplate assay based on in vitro Ellman's method. The IC50 values of all active compounds were calculated. Also, molecular docking studies were performed to evaluate the binding orientations of the isolated compounds inside the active sites of cholinesterase enzymes. Keywords: Narcissus tazetta subsp. tazetta, antcholinesterase activity; isolation; quality control experiments; structure elucidation studies