Department of Botany, University of Ege Faculty of Science Section of Biology, İzmir, Turkey
The aim of the present work is to investigate the phytochemical content of the grinded stem drog of Rheum ribes L. (Polygonaceae), and to study the biological antioxidant activity of the above ground part extract of Rheum ribes. This plant is distributed in Eastern Turkey locally known as 'ıskın, Uckun or Usgun'. This is the only species of Rheum growing in Turkey (Cullen, 1996).
Plant extraction was obtained with ethanol maceration. Antioxidant activity investigation was performed by DPPH method. Antioxydant activity was determined as 69, 7626% in stems, 91, 6758% in leaves, 94, 4863% in flowers.
Column eluted with cloroform: methanol (95:5) solvent system. 97 from 101 up to the fractions were combined and a new column was established. Hexane: ethyl acetate: methanol (10:10:2) solvent system was used for the second column. The major ingredient in the collected fractions of 22 to 28 was obtained approximately 80% purity. This fractions were combined and third purification column was established with the solvent sysstem of hexane: ethylacetate: methanol (10:10:0.5) and the major compound were purified. 1H NMR and MS datas of the molecule was shown that molecule was β-sitosterylglucoside-6'-octadecanoate. This molecule is the first record of this species.
Keywords: Rheum ribes, isolation, antioxydant activity, β-sitosteryl, extraction.