Phytochemical characterization and screening of in vitro antioxidant proprieties of extracts obtained from plants of Caatinga Biome (Brazil)

There has been an increased interest in knowledge of medicinal plants found in the Caatinga biome [1]. Several local communities often use medicinal plants to treat diseases as an alternative way to health services [2, 3]. The aim of this study is to characterize the phenolic composition (HPLC-DAD) of methanolic leaf extracts of selected species from Caatinga and evaluate their in vitro antioxidant proprieties, using several in vitro tests: DPPH scavenging, iron chelation, inhibition of nitric oxide and superoxide production. The species studied were Sp3 (Caesalpinia ferrea), Sp4 (Anadenanthera peregrina), Sp6 (Mimosa tenuiflora), Sp8 (Syderoxylon obtusifolium), Sp9 (Schinopsis brasiliensis), Sp12 (Maytenus rigida), Sp14 (Capparis flexuosa) and Sp18 (Cleomes spinosa). Results show that leaf extracts have a significant amount of phenolic compounds (e.g. gallic acid, kaempherol and quercetin derivatives, isorhamnetin) leading us to predict a good antioxidant potential for them. Extracts of Sp9 and Sp3 showed the highest antiradicalar activity (DPPH), with EC50 of 38 and 53 µg/ml, respectively. Extracts of Sp18, Sp4 and Sp14 showed higher iron chelation activity (EC50 160 – 220 µg/ml). Extract from Sp4 exhibited the highest ability to inhibit nitric oxide production (EC50 87 µg/ml). Extract from Sp3 showed the best ability to scavenge the production of superoxide radical (EC50 20 µg/ml). We can conclude that some extracts have good potential as antioxidants, namely Sp3, Sp4 and Sp14, probably because of their higher contents in phenolic compounds with antioxidant properties. A more complete characterization of these antioxidant potential is ongoing with cellular models, which could lead us to characterize important bioactivities and thus constitute an added value to plants from Caatinga biome and to the inhabitants of this region.

Acknowledgements: This work was supported by Fundação para a Ciência e Tecnologia (FCT), projects PTDC/AGR-ALI/105169/2008 and Pest-OE/AGR/UI4033/2014.

Keywords: Caatinga Biome plants, antioxidant activity, phenolic profiles

References:

[1] Cartaxo S, Souza M, Albuquerque U. Medicinal plants with bioprospecting potential used in semi-arid northeastern Brazil. J Ethnopharmacol 2010; 131(2): 326 – 342.

[2] Almeida C, Amorim E, Albuquerque U, Maia M. Medicinal plants popularly used in the Xingo region – a semi-arid location in Northeastern Brazil. J Ethnobiol Ethnomed 2006; 2(1): 15.

[3] Lucena R, Albuquerque U, Monteiro J, Almeida C, Florentino A, Ferraz J. Useful Plants of the Semi-Arid Northeastern Region of Brazil – A Look at their Conservation and Sustainable Use. Environ Monit Assess 2007; 125(1 – 3): 281 – 290.