Antioxidant activity of selected Peruvian medicinal plants used in Calleria District

The inceasing evidence that free radical-mediated damage to membranes, other lipid-containing structures, DNA and protein contributes to ageing and chronic diseases, such as cancer and coronary heart disease, has focused attention on natural antioxidants, which can play an important role in prevention of these diseases [1]. Therefore there is escalating interest in searching new antioxidants in medicinal and dietary plants [2]. The plants tested in this study were selected based on their traditional use in folk medicine among the Shipibo-Conibo ethnic group in Calleria District, Peru.

The ethanol extracts of 14 Peruvian medicinal plants have been tested for their potential in vitro radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) in microplate assay [3]. Ascorbic acid was chosen as a standard pure compound next to ethanol extract of rosemary – a well documented plant with significant antioxidant activity [4].

All the crude extracts were found to have scavenging effects on DPPH in the range of 5.34–242µg/ml. Among them, Calycophyllum spruceanum (Benth.) K. Schum., Naucleopsis glabra Spruce ex Pittier, Triplaris sp., Phyllanthus ninuri L., Uncaria tomentosa (Willd.) DC. and Maytenus macrocarpa (Ruiz & Pav.) Briq. possessed the strongest activity (EC₅₀ 5.34; 5.45; 6.79; 6.91; 7.90 and 7.94µg/ml resp.) comparable to Rosmarinus officinalis L. extract (EC₅₀ 7.84µg/ml) and ascorbic acid (EC₅₀ 4.64µg/ml).

References: [1] de Beer, D. et al. (2005) Food Chem 90: 569–577. [2] Wiseman, H. (1996) J Nutr Biochem 7: 2–15. [3] Fukumoto, L.R. et al. (2000) J Ag Food Chem 48: 3597–3604. [4] Almela, L. et al. (2006) J Chromatogr A, 1120: 221–229.