Polyisoprenylated benzophenone derivatives from the fruits of Garcinia cambogia and their absolute configuration by quantum chemical circular dichroism calculations

Three new tetracyclic polyisoprenylated xanthones, named oxy-guttiferones M, K2, and I, along with oxy-guttiferone K and guttiferone M, have been isolated from the fruits of Garcinia cambogia. Their structures were elucidated by MS and NMR spectroscopic experiments. The absolute configurations of oxy-guttiferone K, taken as a model of tetracyclic xanthones, and guttiferone M, as a model of polyisoprenylated benzophenones, have been determined by comparison of their experimentally measured circular dichroism (CD) curves with the TDDFT-predicted curves.