Phenolic constituents of the inflorescences of Sorbus torminalis (L.) Crantz

Abstract

Torminaloside, a new acylated flavonol glycoside (3,5,7,4′-tetrahydroxy-3′-methoxyflavone-3- O-[6″- O-(3‴-hydroxy-3‴-methylglutaroyl)]- β- d-galactopyranoside, 6), together with five further methoxylated flavones 1–5, hyperoside ( 7), isoquercitrin ( 8), chlorogenic acid ( 9) and neochlorogenic acid ( 10), were isolated for the first time from Sorbus torminalis (L.) Crantz. The structures of the isolates were elucidated by extensive spectroscopic studies, including UV, IR, 1D- and 2D-NMR, LSI-MS and HR-LSI-MS experiments. In addition to torminaloside, three further flavonoids: 5,7,4′-trihydroxy-3′-methoxyflavone-7- O- β- d-glucopyranoside ( 1), 3,5,7,4′-tetrahydroxy-8,3′-dimethoxyflavone-3- O- β- d-glucopyranoside ( 2), and 3,5,7,4′-tetrahydroxy-3′-methoxyflavone-3- O- β- d-galactopyranoside ( 4) were found for the first time in the genus Sorbus.