Biological Activity of Different Alkaloid Chemotypes of Galanthus elwesii and Galanthus nivalis

Abstract

The discovery of natural sources of biologically active compounds is crucial to medicine, organic farming, plant science, etc. Amaryllidaceae alkaloids are unique compounds of plant origin with a wide variety of biological and pharmacological properties. In the present study, six different chemotypes of Galanthus populations of Bulgarian origin were used for the isolation of alkaloid extracts. The alkaloid extracts were analyzed by GC--MS, and their capability to inhibit acetylcholinesterase, Lolium perenne seed germination and root elongation was assessed. In total, 73 alkaloids of 8 main structural types were detected. Tazettine and lycorine types were predominant in G. nivalis samples, whereas tyramine, lycorine, homolycorine and galanthamine types were most abundant among G. elwesii samples. Sample GE2110, containing 74% galanthamine type alkaloids, achieved the strongest inhibition on acetylcholinesterase (IC₅₀ = 1.32 ± 0.09 μg/mL), but also the weakest inhibition on seed germination (8 ± 5%}) and root elongation (43 ± 17%). Sample GN028A, containing 51% tazettine type alkaloids, was established as the best overall extract, with a strong inhibition on acetylcholinesterase (IC₅₀ = 21.86 ± 1.59 μg/mL), L. perenne seed germination (75 ± 16%) and root elongation (99 ± 1%). Plant species rich in these alkaloids could be the base of a novel biocidal agent against pests and weeds.