Determination of seasonal variation in alkaloid content,morphological characterizataon and evaluation of biologicalactivities of Leucojum aestivum L. (summer snowflake)populations growing in different locations of turkey

Leucojum aestivum L. (summer snowflake), bulbous plant of Amaryllidaceae family, is a well-known producer of pharmaceutically important alkaloid galanthamine for the treatment of Alzheimer's disease. Another striking alkaloid lycorine has strong antiviral activity especially against SARS-CoV-2 (COVID-19). Objective of the study was to determine the best population of L. aestivum in regard to galanthamine and lycorine content by correlating the growing seasons of the plant, soil micro and macro elements, and monthly average temperature and precipitation. Morphological measurements, total phenol-flavonoid content, antioxidant capacity and antibacterial potential were also evaluated. Bulbs and leaves of L. aestivum were collected from 6 different locations in Turkey (Gölcük-Bolu, Yeniçağa-Bolu, Kaynarca-Sakarya, Delmece-Yalova, Uluabat-Bursa and Terkos-İstanbul) at 3 different growing periods (vegetative, reproductive and ripening). Sample collection also continued after leaf senescence for two locations in Bolu. Bulbs and leaves were quantitatively analyzed for their alkaloid content with HPLC-DAD. Generally, vegetative and ripening periods were efficient in alkaloid production and higher temperature increased the alkaloid content of the bulbs. Neutral to slightly alkaline soils with high organic matter content were effective in enhancing the alkaloid content. In the numerical evaluation of all taxa, principal component and cluster analysis were used, and two locations in Bolu were the most similar than other locations. Higher antioxidant capacity was observed with leaves in relation with the highest total phenolic content and tested bacteria were not susceptible to the extracts. The locations of Yalova and Bolu-Gölcük provided galanthamine rich population and optimal growing conditions for the cultivation of this species.