Abstract A study has been made of natural C-methylflavones and their dealkylated analogues: 5-hydroxy-4′, 7-dimethoxy-7-methylflavone (noreucalyptin); 4′, 5, 7-trihydroxy- 6-methylflavone; 5-hydroxy-4′, 7-dimethoxy-6, 8-dimethylflavone (eucalyptin); 4,′ 5-