IJUP08 - Universidade do Porto

Phenolic compounds, organic acids and antioxidant properties of
Rumex induratus
L. Guerra 1 , C. Pereira 1 , R. Gonçalves 1 , P. B. Andrade 1 , R. M. Seabra 1 , P. Valentão 1
1
Department of Pharmacognosy, Faculty of Pharmacy, University of Oporto, R. Aníbal Cunha,
164, 4050-047 Oporto, Portugal.
Rumex induratus Boiss. & Reuter is an endemic Iberian herb, which fundamentally
develops in the thermo Mediterranean region. It grows spontaneously in Northeast Portugal
where its leaves are highly consumed. This species is very appreciated in salads and, to
attenuate its acidity, is dressed with olive oil and sometimes mixed with boiled potatoes.
The chemical composition of aqueous extract of R. induratus leaves, in terms of phenolic
compounds and organic acids, and its antioxidant activity against DPPH radical and a
Reactive Nitrogen Species, nitric oxide ( NO), were studied.
Minutes
Fig. 1. HPLC-DAD phenolic profile
of R. iduratus aqueous extract. (1)
caffeoyl-hexoside; (2) p-coumaroylhexoside;
(3) feruloyl-hexoside; (4)
sinapoyl-hexoside; (5) 6-C-hexosylquercetin;
(6) 8-C-hexosyl-luteolin;
(7) 6-C-hexosyl-luteolin; (8) 6-Chexosyl-apigenin;
(9) 3-O-hexosylquercetin;
(10) 3-O-rutinosylquercetin;
(11) 7-O-hexosyldiosmetin;
(12) 3-O-rutinosylisorhamnetin;
(a) and (b) unidentified
O-glycosil-C-glycosilflavones.
Twelve phenolic compounds were identified by HPLC/DAD, based on previous work [1]
(Fig. 1). Six organic acids were determined by HPLC-UV: oxalic, citric, malic, ascorbic
and shikimic acids.
Some variations in the phenolics and organic acids profiled are discussed, regarding the
influence of the origin, developmental stage and crop season of the samples.
R. induratus aqueous extract revealed scavenging activity against both radicals, in a
concentration dependent manner. 7-O-Glucosyl luteolin, a structurally related compound
and oxalic acid were also tested. The phenolic compound displayed a strong activity while
oxalic acid had no effect. Thus, the antioxidant capacity found for R. induratus extract can
be mainly ascribed to this class of compounds.
References:
[1] Ferreres, F., Ribeiro, V., Izquierdo, A.G., Rodrigues, M.A., Seabra, R.M., Andrade, P.B.,
Valentão, P., (2006) Rumex induratus Leaves: an Interesting Dietary Source of Potential Bioactive
Compounds. J Agric Food Chem, 54, 5782-5789.
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