H-1 and C-13-NMR and biological activity investigations of four lichen-derived compounds

The lichen-derived natural products, atranorin (1), hopane-6 alpha; 22-diol (2), usnic acid (3), and vulpinic acid (4) were analysed by both one and t wo-dimensional (H-1, C-13)-NMR. Experiments employed included COSY, NOESY, XHCO, HMQC and HMBC. For 1 and 2, fully assigned proton NMR data are report ed for the first time; the reassigned C-13 NMR data for both 1 and 2 are al so reported. For 3, cross-peaks were observed in the HMBC spectrum that sug gest that CH long-range coupling through H bonds is occurring. Biological a ctivity investigations of each compound indicated hopane-6 alpha, 22-diol ( 2) to have anti-tubercular activity (MIC 8 mu g/mL) and usnic acid (3) to b e very weakly cytotoxic (ED50 13 mu g/mL). Copyright (C) 1999 John Wiley & Sons, Ltd.