Abstract. Extracts of four species of Lamiaceae family medicinal plants (Agastache Foeniculum, Nepeta cataria, Melissa officinalis and Lavandula angustifolia) used in phytotherapy were screened for flavone content in two different harvest periods and two different hours of the day. Through this research we want to emphasize the optimal harvest time of vegetal raw material, when the studied plants contain the maximum active principles. The content of flavone/flavonols, main phenolics contained by these plants, was determined spectrophotometrically, according to Dowd method in APHIS Laboratory from USAMV Cluj-Napoca, with a Synergy 2 spectrophotometer, microplate reader. Duplicate samples of each plant were harvested for determinations from raw plant (fresh) and dry material. Following the data from Agastache Foeniculum and Nepeta cataria, the highest flavone content was obtained from the raw material harvested on 09/06/2014, at 16 hour, in both fresh and dried raw material. In the Melissa officinalis species, the highest flavone content was found in raw material (fresh and dry) which was harvested on 09/06/14, 11 hour. The highest flavone content in Lavandula angustifolia was found on 19/06/2014, 11 hour, in the fresh material and at 16 hour in the dry one. For the four studied species, the obtained results regarding the flavone content show that the optimal time of harvest was 09/06/2014, ie at the beginning of flowering, except for the species Melissa officinalis for which the flowering occured after 20/06/2014.

Keywords: Agastache foeniculum, Nepeta cataria, Melissa officinalis, Lavandula angustifolia, polyphenols

Presentation: oral