Chemical characterization of Allium ursinum L. depending on harvesting time.

Sulfur-containing compounds of ramson (Allium ursinum L.) are responsible for its traditional use in terms of culinary and medicinal purposes. Leaves and bulbs were investigated for their contents of cysteine sulfoxides (volatile precursors) as well as volatile compounds released from minced plant material. Plants were analyzed during the whole vegetation period, focused on the months from March to June. Additionally, within the dormancy period bulbs were analyzed again and alliinase activity was determined. The pattern of volatile compounds was analyzed both by SPME/GC-MS and by SDE/GC-MS. Compared to each other, SDE exhibited a wider spectrum of detectable volatile compounds. The quality and quantity of volatiles significantly depended on the time of harvest. The highest amounts of volatile precursors can be gained in March and April, shortly before flowering time (up to 0.4% of total cysteine sulfoxides). The main cysteine sulfoxides were alliin and isoalliin. It has been found that alliinase of A. ursinum exhibited properties similar to those of alliinase of garlic (Allium sativum L.), but differing in terms of substrate specificity.