The experiment was carried out in the year 2013. The experimental plant material consisted of herb (leafy flowered stems) and leaves of periwinkle (Catharanthus roseus (L.) G. Don). The aim of the study was to compare the content of biologically active compounds (L-ascorbic acid, total polyphenols), dry matter, and antioxidant activity of fresh and dried plant material. Moreover, on the base of the dried plant material (herb and leaves of periwinkle), three kinds of water extracts were prepared: infusions, decoctions and macerates; with three times of extraction. In the obtained water extracts content of dry matter, L-ascorbic acid, total polyphenols and antioxidant activity were determined. On the base of the study results it was shown that fresh leaves of periwinkle had higher biological value in comparison with its herb. However, after drying process higher content of biologically active compounds was noted for the herb. 15 min/h decoction was found to be the most effective method of water extraction of dried perwinkle herb and leaves. Moreover, herb water extracts were characterized by higher content of polyphenols, while leaf water extracts – by higher content of dry matter, L-ascorbic acid and antioxidant activity
