Potential Antioxidants in Bio-oil Obtained by Pyrolysis of Yew (Taxus baccata L.) Tree Bark

Bio-oil (BO), ethanol extract (EtE), and superheated ethanol extract (SHEtE) from the bark of Taxus baccata L. tree trunk fallen due to strong wind or landslide were obtained from pyrolysis of the crushed sample in the furnace at a temperature of 500 °C for 30 min, ordinary solvent extraction of air-dried powder sample for 24 hours using a 250 mL laboratory-scale Soxhlet extractor, and a small laboratory-scale reactor with a 50 ml cylindrical stainless steel vessel and maximum working temperatures of (300 ± 3) °C for superheated solvent extraction, respectively. The BO and extracts were analyzed for their antioxidant activities using the DPPH method. The presence of organic compounds in the BO and extracts was predicted by analyzing the functional groups using Fourier transform infrared (FTIR) spectroscopy. Among the BO and extracts from yew bark, the most active fraction was analyzed for its chemical composition using gas chromatography-mass spectrometry (GC/MS). BO was proven to have a higher antioxidant capacity (58.76 %) compared to the standard ascorbic acid (45.14 %) at a concentration of 1000 ppm. The FTIR analysis suggested the presence of active compounds in BO samples. The quantification of the BO and extracts showed that yew bark BO was richer in phenolic compounds than the extracts. The major components identified in the BO by GC/MS analysis were guaiacol (11.65 %), followed by phenol (8.48 %), β-D-Glucopyranose, 1,6-anhydro- (6.54 %), furfuryl alcohol (5.64 %), 3,4-dihydro-2H-pyran (5.52 %), p-cresol (4.50 %), 4-methylguaiacol (4.24 %), 3-methylcyclopent-2-enone (3.45 %), 2-hydroxy-3-ethylcyclopent-2-en-1-one (3.29 %), and catechol (3.23 %).