Evaluation of volatile compounds, phenolic acids, antioxidant potential and DFT study of essential oils from different parts of Araucaria columnaris (G. Frost.) Hook. from India.

This study is aimed to investigate the aroma composition, phenolic acid, antioxidant activities and computational analysis of essential oils of five different parts of A. columnaris (G. Frost.) Hook. from India. The essential oils were obtained from the fresh root, stem, leaves, bark, and branch of A. columnaris by hydro-distillation using a Clevenger apparatus: the volatile composition was examined by GC-MS; the phenolic acid quantification by RP-HPLC-DAD and the estimation of antioxidant potential by TAC, FRAP, CUPRAC, MCA, DRSC, and NOSC assays. Total 136 chemical compounds i.e. root-60, stem-55, leaves-50, bark-55 and branch-42 were identified in essential oils by GC-MS and major constituents were β-pinene, terpinolene, 2-nonanone, pinocarveol, trans-verbenol, dihydrocarvone, dodecane, thymol, isolongifolene, α-copaene, α-gurjunene, β-caryophyllene, isoledene, γ-muurolene, γ-cadinene, etc. The five phenolic acid contents were determined by RP-HPLC-DAD with AR: 91-99%, LOD: 0.010269-0.119857 mg/g and LOQ: 0.039553-0.003388 mg/g. The Density Functional Theory (DFT) study was carried out on the main phytochemicals present in essential oils of A. columnaris in a manner to support the experimental results and give detailed of antioxidants and reactivity parameters. The results suggested that the essential oils of A. columnaris have high antioxidant potential due to the presence of phenolic acids and aroma compositions.