Agrorefinery of Tanacetum vulgare L. into valuable products and evaluation of their antioxidant properties and phytochemical composition

Volatile oils constitute only a minor fraction in the essential oil (EO) bearing plants, therefore their distillation residues should be processed into other valuable products. Tanacetum vulgare investigated in this study yielded 0.52 mL 100 g−1 of EO containing 86% of β-thujone. Liquid hydrodistillation residue was dried yielding water extract (WE), while solid residue and the whole material were extracted with acetone obtaining acetone oleoresin (AO) and deodorized acetone extract (DAE). Antioxidant properties of tansy extracts were evaluated by different in vitro and in situ methods. Total phenolic content in the extracts was in the range of 34.0-142.3 mg gallic acid equivalents/g, effective radical scavenging concentrations (EC50) were 1.33-13.19 mg/mL (DPPH*), 1.40-3.49 mg/mL (ABTS*+), while ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) values were, 157.3-546.2 and 4285.4-11947.5 μmol trolox equivalents/g, respectively. WE was the strongest antioxidant in vitro assays and in stabilizing mayonnaise, while AO additives were the most effective in stabilizing rapeseed oil, and the PFs obtained were 2.46 and 2.83, respectively. The on-line HPLC-UV-DPPH* analysis showed that mono and dicaffeoylquinic acids were the major contributors to the antioxidant capacity of WE. Fifteen phenolic constituents (mainly derivatives of luteolin, apigenin and chlorogenic acid) were identified in T. vulgare extracts by UPLC/Q-TOF/MS2. In general, the study demonstrated strong antioxidant potential of T. vulgare and results obtained may assist in selecting the most valuable tansy extracts for the production of bioactive ingredients for foods, medicinal and biotechnological or agricultural applications.