Seasonal dynamic of main classes phenolics and radical scavenging activity of invasive tree Ailanthus altissima extracts

Aerial herbal substances from Ailanthus altissima were the subject of the present study, which aimed to follow the dynamics in the accumulation of bioactive compounds with antioxidant potential during vegetation, namely polyphenols, flavonoids, phenolic acids, and tannins quantified by pharmacopoeial methods. Aqueous and ethanolic extracts from dry plant material (under reflux and heating at 200°C) and ethanolic extracts from fresh plant material (under vacuum) were prepared to determine the optimal conditions for the extraction process of the antioxidant active components. Radical scavenging activities (according to ABTS and DPPH in vitro assays) were found for all tested extracts. Flower buds and flower extracts demonstrated the best results, followed by leaves and stem bark, which correlated with the total polyphenols and flavonoid content found. Vacuum extracts of flowers collected at the beginning of flowering were distinguished by the strongest antioxidant potential (3272.28 ABTS mmol TE/g dw and 2125.67 DPPH mmol TE/g dw). The same type of extract is also suitable for stem bark (411.61 ABTS mmol TE/g dw) for which the collection period is the beginning and the end of the growing season. Ethanolic leaf extracts (collected at the beginning flowering stage) with the application of temperature treatment exhibited the best antioxidant potency (504.75 ABTS mmol TE/g dw and 404.72 DPPH mmol TE/g dw) for this plant substance. The results of the present study provide a good basis for future research on Ailanthus altissima intending to incorporate it into phyto-preparations with strong antioxidant activity.