Blackberries are an important option for the diversification of fruit crops. However, there is currently no literature regarding plant cultivation in high-altitude tropical climates. Knowledge of the phenolic composition of blackberries is essential because variations in the levels of these components may exist between cultivars and may depend on environmental conditions. High performance liquid chromatography (HPLC) was used to evaluate the total phenol content of different blackberry cultivars (Arapaho, Brazos, Cainguangue, Cherokee, Choctaw, Comanche, Ébano, Guarani, Tupy and Xavante). Free radical scavenging activity in these cultivars was assayed using a DPPH test. The HPLC-UV chromatogram of blackberry fruit extracts at 280 nm revealed the presence of phenolic compounds. The results showed significant differences in the levels of phenolic compounds in the blackberry cultivars tested. Antioxidant activity was evaluated using the ABTS free radical and ranged from 2.7 ± 0.1 to 19 ± 2 μmole of Trolox equivalents per gram of sample (b.u.). These results are in good correlation with the phenolic contents of the blackberries tested. The Xavante blackberry cultivar had the highest levels of polyphenols that could be individually identified. Catechin polyphenols were found to be the main component in the blackberry varieties tested.

Secondary metabolites are important organic metabolites produced by plants. These metabolites include phenolic compounds, which have been of research interest because phenolics are considered an antinutritional factor for ruminants, compromise the bioavailability of nutrients. This study included a chemical composition analysis, an analysis of the condensed tannin content and the identification and quantification of the phenolic compounds present in the following plants cultivated with and without fertilisation: Coastcross-1 grass (G) and the legumes Stylosanthes guianensis cv. Mineirão (MS), Stylosanthes capitata × Stylosanthes macrocephala cv. Campo Grande (CGS), Arachis pintoi cv. Amarillo (AA) and Arachis pintoi cv. Belmonte (AB). High-performance liquid chromatography (HPLC) was used to analyse 13 phenolic compounds. The forage with the best nutritive value was Amarillo pinto peanut. The condensed tannin content was higher in the legumes than that in the grass. Vanillin and o-coumaric, m-coumaric, caffeic and ferulic acid were detected in all the cultivars. The cultivar with the largest variety of phenolic compounds was Coastcross-1 grass. Diversity existed in the occurrence of phenolic compounds, which indicated the presence of condensed tannins in the cultivars and possibly that the diversity does not affect the concentration of these compounds. The AA cultivar was the most interesting alternative for the establishment of pasture intercropped with Coastcross-1 grass.