title: Glabridin.
abstract: In the title compound, C20H20O4 {systematic name: 4-[(3R)-8,8-dimethyl-3,4-dihydro-2H-pyrano[2,3-f]chromen-3-yl]benz-ene-1,3-diol}, the hydro-pyran ring linked to the pendant benzene ring adopts an envelope conformation, with the methyne C atom forming the flap. In the crystal, the -OH group at the 3-position of the benzene ring forms an O-H⋯O hydrogen bond to a chromene O-atom acceptor, whereas the -OH group at the 1-position forms an O-H⋯π inter-action with a neighboring benzene ring. The O-H⋯O hydrogen bonds form [001] chains and the O-H⋯π bonds cross-link the chains into (101) sheets. The absolute structure was assumed to be the same as that deduced from previous studies for the natural product.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University and Nanotec-PSU Center of Excellence for Drug Delivery Systems, Hat-Yai, Songkhla 90112, Thailand.
authors.forename: Vimon
authors.initials: V
authors.lastname: Tantishaiyakul
authors.forename: Krit
authors.initials: K
authors.lastname: Suknuntha
authors.forename: Saowanit
authors.initials: S
authors.lastname: Saithong
authors.forename: Chaveng
authors.initials: C
authors.lastname: Pakawatchai