Hydroxycinnamic derivatives content in plant organs linked to harvest time of Salvia officinalis L. cv. ‘Krajová’ / Obsah hydroxyškoricových derivátov v rastlinných orgánoch Salvia officinalis L. cv. ‘Krajová’ v závislosti od termínu zberu

Salvia officinalis L. (sage) is an important essential oil containing Mediterranean medicinal plant that is commonly cultivated for pharmaceutical uses. In addition to essential oil, other compounds participate on the biological effects of sage, mainly diterpenes, triterpenes and phenolic compounds of the hydroxycinnamic and flavonoid types. Sage essential oil content is known to differ in plant parts, and to be influenced by plant phenophase, climatic and edaphic conditions. This work deals with the study of total hydroxycinnamic derivatives (THD), and specifically rosmarinic acid (RA), content variation in different aerial parts of sage linked to different harvest times. Dry sage leaves (Salviae officinalis folium) THD content was quantified using a pharmacopoeial method, and varied between 3.06 % and 3.52 % in different harvest times, with maxima in youngest plant shoot leaves and newly-grown shoots in September. Sage stems showed similar THD content variations when linked to harvest times, however with lower percentage, 1.33 - 3.04 %. Rosmarinic acid variability showed the same trends, its content ranged between 0.76 % and 1.65 % in leaves, and between 0.19 % and 0.83 % in stems, respectively. Highest percentages of both THD and RA were found in top leaves, lowest in leaves from the middle of the stem. When linked to plant phenophase, the content of THD and RA decreased at flowering time.