Antiviral phenylpropanoid glycosides from the medicinal plant Markhamia lutea

Three new phenylpropanoid glycosides, named luteoside A (3), luteoside B (4), and luteoside C (5), were isolated together with the known compounds verbascoside (1) and isoverbascoside (2) from the roots of the medicinal plant Markhamia lutea. The structures of the new compounds were determined to be 1-O-(3,4-dihydroxyphenyl)ethyl beta-D-apiofuranosyl(1-->2)-alpha-L-rhamnopyranosyl(1-->3)-4-O-caffeoyl-6-acetyl- beta-D-glucopyranoside, 1-O-(3,4-dihydroxyphenyl)ethyl beta-D-apiofuranosyl(1-->2)-alpha-L-rhamnopyranosyl(1-->3)-6-O-caffeoyl-beta-D-glucopyranoside, and 1-O-(3,4-dihydroxyphenyl)ethyl beta-D-apiofuranosyl(1-->2)-alpha-L-rhamnopyranosyl(1-->3)-6-O-feruloyl-beta-D-glucopyranoside, respectively, on the basis of chemical and spectroscopic data. All five phenylpropanoid glycosides exhibited potent in vitro activity against respiratory syncytial virus.