Fig. 1: compounds 1 (assiguxanthone-B), 2 (1,3,5,6-tetrahydroxy-2-prenylxanthone), 3 (2,5-dihydroxybenzoic acid), 4 (kielcorin) from Kielmeyera variabilis and 5 (calozeyloxanthone) from Calophyllum ...