Phytochemical Screening, Antioxidant and Antibacterial Activity of Encholirium spectabile (Bromeliaceae)

The phytochemical screening, antioxidant and antibacterial activities of extracts from Encholirium spectabile, a species belonging to the Bromeliaceae family, were investigated. This species is known in Brazil as “macambira de flecha†. In this study, the phenolic and flavonoid contents were determined by the Folin-Ciocalteu and aluminum chloride methods, respectively. Antioxidant activities were evaluated by using DPPH radical scavenging and β-carotene-linoleic acid bleaching and compared with the reference compounds ascorbic acid, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). The antibacterial effect was evaluated by the method of microdilution. Preliminary analysis demonstrated that the extracts were found to be positive for the presence of flavonoids, tannins, lignans, monoterpenes, diterpenes, steroids and triterpenoids. The most significant total phenolic content was of 206.4 ± 29.14 mg of gallic acid equivalent/g for ethyl acetate extract (AcOEt), and 106.7 ± 3.35 for chloroform extract (CHCl3). The total flavonoids content was of 279.3 ± 18.88 mg of catechin equivalent/g for AcOEt extract. The AcOEt extract presented the best antioxidant activity (IC50 18.51 ± 2.90 μg/ml) for DPPH scavenging. BHA was the most effective antioxidant. The chloroform and ethyl acetate extracts showed activity against most of the microorganisms tested, especially Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Serratia marcescens, Shigela flexneri and Staphylococcus aureus. Future investigations will be focused on isolation of chemical constituents.