title: Anthraquinone glycosides from Cassia roxburghii and evaluation of its free radical scavenging activity.
abstract: The methanolic extract of the leaves of Cassia roxburghii DC., was investigated for its anthraquinone glycosides and antioxidant activity. Two new anthraquinone glycosides named emodin 1-O-β-D-glucopyranosyl-(1 → 2)-glucopyranoside (1) and aloemodin 8-O-β-D-glucopyranosyl-(1 → 6)-glucopyranoside (2) along with aloemodin 8-O-β-D-glucopyranoside (3), emodin (4), aloemodin (5) and one flavonoid, quercetin-3-O-α-L-rhamnopyranoside, were isolated from the leaves of C. roxburghii. Structures of the isolated compounds were established by UV, HRESI-MS, and 1D/2D (1)H/(13)C NMR spectroscopy. The total extract and some isolated compounds were determined against DPPH (2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazinyl radical, for their free radical scavenging activity, the total alcoholic extract showed strong antioxidant activity while the two new compounds showed weak antioxidant activity.
authors.affiliation: Chemistry of Tannins Department, National Research Center, El-Bohouth St, Dokki, 12622 Cairo, Egypt. sayedeltomy@yahoo.com
authors.forename: Sayed A
authors.initials: SA
authors.lastname: El-Toumy
authors.forename: Sahar S
authors.initials: SS
authors.lastname: El Souda
authors.forename: Tahia K
authors.initials: TK
authors.lastname: Mohamed
authors.forename: Iñaki
authors.initials: I
authors.lastname: Brouard
authors.forename: Jame
authors.initials: J
authors.lastname: Bermejo
mesh_terms: D000880:Anthraquinones / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D002366:Cassia / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D006027:Glycosides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry*
chemical_list: D000880:Anthraquinones; D016166:Free Radical Scavengers; D006027:Glycosides