Complete NMR assignments of the antibacterial biflavonoid GB1 from Garcinia kola.

From the antibacterial fraction of the roots of Garcinia kola, 3'',4',4''',5,5'',7,7''-heptahydroxy-3,8''-biflavanone (GB1) was isolated as the major constituent, whose interesting conformations were studied on the basis of its 1D and 2D NMR spectra obtained at different temperatures and in different solvents. GB1 showed antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) with MIC of 32 and 128 microg/ml, respectively.