Seasonal and spatial variations in the concentration of phenols in Elaeagnus angustifolia L.

Abstract

Objective: To characterize the variations in the phenol content in the different edible and non-edible portions of Elaeagnus angustifolia L. during the growth cycle of the plant. Materials and Methods: Plant material was collected during the plant growth cycle in the Valle Medio region, Río Negro, Argentina. The collection was carried out in five sampling moments (September, November, January, February and March). For such purpose, samples were taken from the leaves, flowers and fruits of the canopy exposed to the sun and leaves in the shaded canopy. The presence of polyphenols in the different samples collected by qualitative and quantitative essays was evaluated. The data were analyzed through variance analysis; while the significant differences among means, by Tukey’s test for p < 0,05. The statistical program Infostat® was applied. Results: Significant differences (p < 0,05) were found in the content of polyphenols between the external sunlit sunny leaves and the inner shaded ones in the September sampling. The shaded leaves contained significantly more phenolic compounds than the higher sunlit sunny leaves (19,8 and 16,4 mg GAE g-1 DM, respectively). This variability becomes null, when the total edible thyrse is compared with the non-consumed parts. Conclusions : Seasonal and spatial variation was determined in the concentration of total phenols in the edible and non-edible biomass of E. angustifolia during its growth cycle. In addition, no limiting quantities of polyphenols were found in the shaded leaves, which could reduce the voluntary intake of feed and its digestibility.