Purification procedure for (2R,3S,2aEuro(3)R,3aEuro(3)R)-manniflavanone and its minor (2R,3S,2aEuro(3)S,3aEuro(3)S)-isomer from Garcinia buchananii stem bark

(2R,3S,2aEuro(3)R,3aEuro(3)R)-Manniflavanone (1) and its minor isomer (2R,3S,2aEuro(3)S,3aEuro(3)S)-manniflavanone (2) are known for their very high in vitro antioxidative activities. Preliminary data revealed several promising bioactivities, which have to be further evaluated in detail. To enable these investigations as well as animal and/or preclinical studies, preparative amounts of (2R,3S,2aEuro(3)R,3aEuro(3)R)-manniflavanone (1) are highly demanded. Therefore, we developed a fast and efficient three-step isolation procedure, which includes extraction of the stem bark, pre-separation via MPLC of the crude extract and a final isocratic preparative HPLC purification. Within about 3 days in total, 1 g of pure (2R,3S,2aEuro(3)R,3aEuro(3)R)-manniflavanone (> 98 % purity UV) could be isolated by means of isocratic preparative (flow rate 42 mL/min) HPLC separation of the corresponding MPLC fraction.