A New Vomifoliol Derivative and Flavonoids from the Aerial Parts of Orthosiphon aristatus

Orthosipon aristatus (Lamiaceae) is a perennial herbaceous plant native to tropical Southeast Asia countries. The chemical investigation on this plant led to the isolation and structure elucidation of a new vomifoliol derivative (1) along with eighteen known phenolic compounds cystosiphonin (2), 5,7,8-trimethoxyflavanone (3), scutellarein-7,4′-methylether (4), eupatorin (5), 5,6,7,8,4′-pentamethoxyflavone (6), 5,6,7,4′-tetramethylscutellarein (7), 5,6,7,8,3′,4′-hexamethoxyflavone (8), 6-hydroxy-5,7,4′- trimethoxyflavone (9), 6,7,8,3′,4′-pentamethoxyflavone (10), 5,6,3′-trihydroxy-7,4′-dimethoxyflavone (11), 5,6-dihydroxy-7,3′,4′-trimethoxy flavone (12), 4′-hydroxy-5,6,7,3′-tetramethoxyflavone (13), 2′-hydroxy-3,4,4′,5′,6′-pentamethoxy-chalcone (14), isoquercetin (15), quercetin 3-O-α-L-arabinopyranosyl (1→6)-β-Dglucopyranoside(16), caffeic acid (17), rosmarinic acid (18), and (6S,9R)-roseoside (19). The structures of isolates were confirmed via spectroscopic data such as one- and two-dimensional nuclear magnetic resonance, circular dichroism, mass, ultraviolet and optical rotation.