ANTIOXIDANT CAPACITY OF THREE CUBAN SPECIES OF THE GENUS PLUCHEA CASS. (ASTERACEAE)

Leaves of three Cuban species of the genus Pluchea: Pluchea carolinensis, Pluchea odorata and Pluchea rosea were extracted with various solvents and analyzed. Highest values of phenolic compounds were detected after ethyl acetate (EtOAc) and n-butyl alcohol (n-BuOH) extractions. Flavonoids were detected after chloroform, EtOAc and n-BuOH extractions of the species Pluchea and three aglycone flavonol forms (quercetin, kaempferol and myricetin) were also quantified after EtOAc and n-BuOH extractions, using high performance liquid chromatography. The total antioxidant capacity (TAC), expressed as Trolox equivalents per gram of leaf dry weight (TE/g dw) was analyzed using 2,2-diphenyl-1-picrylhydrazyl (DPPH center dot), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and the oxygen radical absorbance capacity. The highest values of TAC were detected after EtOAc and n-BuOH extractions of the three species. P. carolinensis was the most promising species, being the n-BuOH extraction with the most bioactive compounds: 15.3 mg TE/g dw using DPPH center dot.