title: Cycloartane glycosides from Sutherlandia frutescens.
abstract: Four new cycloartane glycosides, sutherlandiosides A-D (1-4), were isolated from the South African folk medicine Sutherlandia frutescens and their structures established by spectroscopic methods and X-ray crystallography as 1 S,3 R,24S,25-tetrahydroxy-7S,10S-epoxy-9,10- seco-9,19-cyclolanost-9(11)-ene 25-O-beta-D-glucopyranoside (1), 3R,7S,24S,25-tetrahydroxycycloartan-1-one 25-O-beta-D-glucopyranoside (2), 3R,24S,25-trihydroxycycloartane-1,11-dione 25-O-beta-D-glucopyranoside (3), and 7S,24S,25-trihydroxycycloart-2-en-1-one 25-O-beta-D-glucoyranoside (4). Compound 1 represents the first secocycloartane skeleton possessing a 7,10-oxygen bridge. Compounds 2- 4 are also the first examples of naturally occurring cycloartanes with a C-1 ketone functionality. Biosynthetic considerations and chemical evidence suggest that the presence of the C-1 ketone in 2 may facilitate the ring opening of the strained cyclopropane system.
authors.affiliation: Department of Pharmacognosy, National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, Mississippi 38677, USA.
authors.forename: Xiang
authors.initials: X
authors.lastname: Fu
authors.forename: Xing-Cong
authors.initials: XC
authors.lastname: Li
authors.forename: Troy J
authors.initials: TJ
authors.lastname: Smillie
authors.forename: Paulo
authors.initials: P
authors.lastname: Carvalho
authors.forename: Wilfred
authors.initials: W
authors.lastname: Mabusela
authors.forename: James
authors.initials: J
authors.lastname: Syce
authors.forename: Quinton
authors.initials: Q
authors.lastname: Johnson
authors.forename: William
authors.initials: W
authors.lastname: Folk
authors.forename: Mitchell A
authors.initials: MA
authors.lastname: Avery
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
mesh_terms: D018360:Crystallography, X-Ray; D007887:Fabaceae / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry* / Q000302:isolation & purification*; D008968:Molecular Conformation; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D013019:South Africa; D013237:Stereoisomerism; D014315:Triterpenes / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D006027:Glycosides; D014315:Triterpenes; C085352:cycloartane