C-glycosyl flavones and a comparative study of the antioxidant, hemolytic and toxic potential of Jatropha multifida leaves and bark

The ethyl acetate extract from Jatropha multifida (Euphorbiaceae) leaves yielded two C-glycosyl flavones. Their structures were elucidated through spectroscopic methods, including UV, IR, 1D and 2D NMR, and compared with the related known compounds. The structures of the two flavonoids were determined as Vitexin ( 1 ) and Isovitexin ( 2 ). The ethanol extracts of leaves and bark and their fractions did not interfere in the integrity of erythrocytes, not even 1 and 2 . In the Brine shrimp lethality method, bark extracts showed greater toxic potential than the leaf extracts. Both flavonoids are not toxic. The Phosphomolybdenum and DPPH assays were used in order to investigate the antioxidant activity of both compounds and fractions of leaf and bark extracts. The ethyl acetate fraction of bark showed excellent activity, with IC 50 17.23 μg/mL -1 , equivalent to the standard values, Vitamin C and Rutin. Compounds 1 - 2 demonstrated good activity with IC 50 values of 54.37 and 87.27μg/mL -1 .  In the Phosphomolybdenum test, the ethyl acetate fraction of bark showed 86.18% of antioxidant activity compared with Rutin, and the chloroform fraction of leaves, 103.29%. In all tests the bark extracts were more bioactive than the leaf extracts.