Influence of Seasonality on Phytochemical Composition, Phenolic Content and Antioxidant Activity of Neoglaziovia variegata (Bromeliaceae)

The production of phytochemicals in plants can be influenced by several factors. This work evaluated the influence of seasonality on phytochemical composition, phenolic content, and antioxidant activity of Neoglaziovia variegata. The leaves were harvested for a year. Phytochemical characterization by thin-layer chromatography indicated the presence of anthocyanins, anthraquinones, anthracene derivatives, flavonoids, tannins, monoterpenes, diterpenes, triterpenes, and steroids in the leaves collected in all months, and coumarins in leaves of 4 of the 12 months of collection. The antioxidant activity, evaluated in vitro, ranged from 33.0 to 86.1% inhibition of DPPH• and from 36.2 to 97.8% inhibition of ABTS•+. The total phenolic content, determined using Folin-Ciocalteu reagent, varied between 21.5 and 65.8 mg GAE/g. Phenolic acids and flavonoids were determined by HPLC-DAD, with higher concentrations of kaempferol (0.47-3.57 mg/g), p-coumaric (0.19-3.59 mg/g) and ellagic (0.26-3.31 mg/g) acids. The Principal Component Analysis (PCA) indicated the separation of the leaf samples according to the season. It was demonstrated the influence of seasonality on the antioxidant activity and phytochemical composition of N. variegata leaves and that this species is rich in secondary metabolites of different classes, with potential applications in several areas, such as pharmaceutical and food.