Antioxidant Activities of Biflavonoids from Indonesia Araucaria columnaris Leaves Kurniawanti1, Dhea Demitri Agusta1, Purwantiningsih Sugita1*, Irma Herawati Suparto1, Hanhan Dianhar2, Dyah Utami Cahyaning Rahayu3
1Departement of Chemistry, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680, Indonesia
2Chemistry Study Program, Faculty of Mathematics and Natural Sciences, Universitas Negeri Jakarta, Jakarta 13220, Indonesia
3Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok 16424, Indonesia
Abstract
One of the biological activity of biflavonoids are reported to have potential as antioxidants. Biflavonoids could be found in various higher plants and one from Araucaria genus is Araucaria columnaris plant. There are eleven biflavonoids have been reported from the leaves of A. columnaris which are grown in Hawaii and India. This species is also grown in the Bogor Botanical Gardens, Indonesia, however, there are no recent studies have been reported on secondary metabolites, especially biflavonoids, from Indonesian A. columnaris. Therefore, this research aimed to isolate biflavonoids from leaves of Indonesian A. columnaris using extraction methods and various chromatographic techniques, such as gravity column chromatography with silica gel and Sephadex LH-20 as a stationary phase, radial chromatography and preparative thin-layer chromatography. Furthermore, the extracts and secondary metabolites isolated were also examined their activity as antioxidants using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Three biflavonoid compounds have been successfully obtained from the acetone extract of A. columnaris leaves, and one of them was successfully elucidated according to their spectroscopic data, including IR, UV-Vis, NMR (1H, 13C, HSQC, and HMBC), and MS spectra as 4^,4^^,7,7^^ -tetra-O-methylcupressuflavone (1). The other two biflavonoids are not yet finished analysis. The preliminary antioxidant assay of acetone extract of the leaves A. columnaris showed moderate activity with IC50 of 69.2 ppm, whereas compound 1 showed weak activity with IC50 >100 ppm.
