Flavonoids from Mimosa xanthocentra (Leguminosae: Mimosoideae) and molecular modeling studies for isovitexin-2″-O-α-l-rhamnopyranoside rotamers

► Four flavonoids were isolated from Mimosa xanthocentra. ► Isovitexin-2″-O-α-l-rhamnopyranoside 1 exists as two rotamers in DMSO-d6 solution. ► MM2 calculations led to the first three-dimensional structure of 1 conformers. ► The energy barrier between both rotamers was also evaluated.