New flavones with antidiabetic activity from Callistemon lanceolatus DC.

Phytochemical investigation of the aerial parts of Callistemon lanceolatus DC (Myrtaceae) led to the isolation of two new flavones characterized as 5,7-dihydroxy-6,8-dimethyl- 4' -methoxy flavone (1) and 8-(2-hydroxypropan-2-yl)-5-hydroxy-7-methoxy-6-methyl-4'-methoxy flavone (2) along with the seven known phytoconstituents. The structures of new compounds have been established on the basis of chemical and spectral studies and known compounds were compared with the published literature data. The isolated flavones exhibited blood glucose lowering effect in streptozotocin induced diabetic rats.