Antioxidant and phytotoxic activity in Brazilian Annonaceae extracts

Annonaceae is one of the richest families of the Brazilian savanna woody component [1]. Some species have previously showed many biological activities, including insecticidal [2] and cytotoxic [3]. The aim of the present study was to evaluate the main compounds present in Annona coriacea, A. crassiflora, Duguetia furfuracea and Xylopia aromatica and to analyze antioxidant and phytotoxic (lettuce achene germination and seedling growth inhibition) activities. To address this goal, leaves and steams were extracted until exhaustion by ethanol. The extracts were re-suspended in methanol and analyzed by HPLC-DAD. The chromatograms revealed that the extracts showed many phenolic acids and flavonols. The major compounds were rutin, quercetin-3-O-galactoside and kaempferol-3-O-galactoside. The antioxidant activity of the extracts was analyzed by DPPH assay. Almost all extracts had high antioxidant activity, showing EC50 values between 0.02 (X. aromatica leaves) and 0.03 mg/ml (D. furfuracea leaves). A. coriacea leaves had the lowest antioxidant activity (EC50 = 0.06 mg/ml). There was almost no important difference in antioxidant activity between leaves and steams extracts. Although lettuce germination and shoot length were not significantly affected by all the extracts, leaf extract of A. coriacea reduced significantly the development of root lettuce seedlings. These results suggest that the phytotoxic activity may be related to an oxidative stress induced by A. coriacea leaves extract. The high antioxidant activity of the other extracts could have prevented any phytotoxic activity in lettuce roots.

Fig. 1: Effect of Xylopia aromatica (X) Annona crassiflora (CR), Annona coriacea (CO), and Duguetia furfuracea (DF) leaf (I) and stem (s) extracts over DPPH and root growth assays.

Acknowledgements: CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for PN fellowship (PNPD – 1273737), FAPESP (Fundação de Amparo à Pesquisa do estado de São Paulo) for financial support (2013/07543 – 0). DYACS is fellow research of CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico).

Keywords: Annonaceae, Brazilian savanna, antioxidant activity, phytotoxic activity, flavonoids

References:

[1] Mantovani, W. & Martins, F.R. 1993. Acta Botanica Brasilica, 7: 33 – 60.

[2] Costa, M.S., Pinheiro, D.O., et al. 2012. Neotrop Entomol, 41: 311 – 314.

[3] Mahmound, T.S., Marques, M.R., et al. 2011. Rev. Bras. Farmacogn. 21: 456 – 464.