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DOI: 10.1055/s-0029-1234549
Anthraquinone glycosides from Cassia roxburghii and antioxidant activity of its extract
The use of natural products with therapeutic properties is as ancient as human civilization and for a long time, mineral, plant and animal products were the main source of drugs [1]. The present study deals with the isolation and identification of anthraquinones from Cassia roxburghii leaves and evaluation of antioxidant activity of the extract. The aqueous alcoholic extract (MeOH:H2O 7:3) of Cassia roxburghii leaves was subjected to extensive repeated column chromatography on polyamide, and Sephadex LH-20 resulted in two new anthraquinone glycosides named emodin 1- O -β- glucoside (2→1) glucopyranoside (1) and aloemodin 8- O -β- glucoside (6→1) glucopyranoside (2) as well as aloemodin 8- O -β- glucoside, emodin and aloemodin. Structures of the isolated compounds were established by chromatography, UV, HRESI-MS and 1D/2D 1H/13C NMR spectroscopy.
The radical scavenging activity of the extract was quantified spectrophotometrically, using DPPH radical. The effective dose 50 (ED50) of the extract was compared with that of standard antioxidants as vitamin C. The free radical scavenging properties were assayed with complementary methods, as electron paramagnetic resonance (EPR) spectroscopy and other UV-visible absorbance based assays.
References: [1] Farnsworth, N.R., Bingel, A.S. (1997) New natural products and plant drugs with pharmacological, biological, or therapeutic activity, Springer, New York.