Antioxidant activity and polyphenol content of aqueous extracts from Colombian Amazonian plants with medicinal use

The total phenol and flavonoid contents of 19 Amazonian plants and their related antioxidant activities were determined. The extracts from the plant leaf, bark, root, fruit and/or stem were prepared as infusions, as are traditionally used in popular medicine. Total phenols ranged from 0.8 to 22.2 mg gallic acid equivalents/g and flavonoids from 0.0 to 10.2 mg catechin equivalents/g, by using Folin–Ciocalteau and aluminium chloride colourimetric methods. Differences were observed in phenol and flavonoid contents at the organic level, the leaf presenting greater values than the stem. All the extracts showed different degrees of antioxidant activity with TEAC, 1.1 up to 117.4 and ORAC, 7.8 up to 359.1 μmol Trolox equivalents/g. These values correlated with total phenol content (r2 = 0.90) and flavonoid content (r2 = 0.70 for TEAC; r2 = 0.76 for ORAC). Piper putumayoense, Piper glandulosissimum, Piper krukoffii and Senna reticulata leaves and Brownea rosademonte bark showed elevated antioxidant activities, thus representing promising plant-sources of medicine.