Samioside, a new phenylethanoid glycoside with free-radical scavenging and antimicrobial activities from Phlomis samia

A new phenylethanoid glycoside, samioside, was isolated from the aerial parts of Phlomis samia and identified as 1-O-3,4-(dihydroxyphenyl)ethyl- beta -apiofuranosyl-(1 -->4)-alpha -L-rhamnopyranosyl-(1 -->3)-4-O-caffeoyl- -beta -D-glucopyranoside (1). In addition, one known phenylethanoid glycoside and three known flavonoids were identified as acteoside (2), apigenin, chrysoeriol, and ermanin, respectively. The structure of 1 was elucidated on the basis of its spectroscopic data. Samioside (1) demonstrated scavenging properties toward the DPPH radical and antimicrobial activity against Gram-positive and -negative bacteria.