Phenolic Profile, Antioxidant and DNA-Protective Capacity, and Microscopic Characters of Ailanthus altissima Aerial Substances

Invasive species as sources of natural components are of increasing interest for scientific research. This is the case of Ailanthus altissima, which belongs to the top 100 of the most dangerous invasive plant species in Europe, and which is the subject of the present study. The purpose of the research was to analyze the main phenolic compounds in the flowers, leaves, and stem bark of A. altissima and determine the DNA-protective and antioxidant potential of their ethanolic extracts. HPLC profiling revealed the presence of 6 flavonoids and 10 phenolic acids, of which 15 were found in flowers, 14 in leaves, and 11 in the stem bark. Rutin (5.68 mg/g dw in flowers), hesperidin (2.67 mg/g dw in leaves) and (+)-catechin (2.15 mg/g dw in stem bark) were the best-represented flavonoids. Rosmarinic (10.32 mg/g dw in leaves) and salicylic (6.19 mg/g dw in leaves) acids were predominant among phenolic acids. All plant extracts tested showed in vitro antioxidant activity (determined by DPPH, ABTS, FRAP, and CUPRAC assays) and DNA-protection capacity (assay with supercoiled plasmid DNA-pUC19). The highest antioxidant activity was recorded in the flower parts (in the range from 661 to 893 mmol TE/g dw), followed by the leaves. A DNA protective potential for A. altissima leaf and flower extracts has not been established to date. In addition, the main microscopic diagnostic features of studied plant substances were described, with data for the flower parts being reported for the first time. The present study proves that A. altissima could be a natural source of DNA protection and antioxidants.