There are several reports of biological activity for kaurenoic acid (1), which is found in the aerial parts of Wedelia paludosa D.C., a herbaceous plant of the Asteraceae family abundant in Brazil, and that contains grandiflorenic acid (2) also. Both of these diterpenes were shown to cause lysis of trypomastigotes of the protozoa Trypanosoma cruzi, the causative agent of Chagas' disease (American trypanosomiasis). This paper reports the quantitative determination of these diterpene acids in the aerial parts of W. paludosa by an isocratic RP-HPLC method employing 60% acetonitrile in water and UV detection (220 nm). Kaurenoic acid (1) was found to be more abundant (0.85 ± 0.08%) while the amount of grandiflorenic acid (2) determined was almost three times lower (0.32 ± 0.02%). No significant seasonal variation was observed for these compounds in W. paludosa growing in Belo Horizonte (MG, Brazil) what points out to the aerial parts of this species are a good source of these biologically active diterpenes along all the year.
Wedelia paludosa; diterpenes; kaurenoic acid; grandiflorenic acid; quantitative determination; RP-HPLC
