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·), 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·. PRACTICAL APPLICATIONS The study of the chemical and biological properties of natural crude extracts from plant sources constitutes an important way for discovering new chemical compounds beneficial for human health. Many disorders in humans are associated with the accumulation of free radicals in the body, as it is the case in atherosclerosis, arthritis, ischemia, central nervous system injury and some cancers among others. In the three Cuban species of the genus Pluchea, high amounts of natural compounds and especially phenolics have been detected. The antioxidant capacity of the plants has been tested by means of three different methods. These three species have high quantities of antioxidant substances that could be used in the treatment of different pathologies. In addition, these three species are well distributed in Cuba and they can be found in dense patches of individuals, so we have also access to high quantities of these natural sources.