Scavenging capacity of strawberry tree (Arbutus unedo L.) leaves on free radicals.
Despite strawberry tree (Arbutus unedo L.) leaves had a long use in traditional medicine due to its antiseptic, diuretic, astringent and depurative properties, the potential of their antioxidant activity are still lacking. Our study goals to assess the antioxidant and free radical scavenging potential of water, ethanol, methanol and diethyl ether extracts of A. unedo leaves. Total phenols content was achieved spectrophotometrically using Folin-Ciocalteau reagent with gallic acid as standard. Antioxidant activity was evaluated using three different methods: reducing power of iron (III)/ferricyanide complex assay, scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and scavenging effect on superoxide radicals by using the PMS-NADH-nitroblue tetrazolium system. Ethanol extracts of A. unedo leaves were the highest in reducing power (IC(50) 232.7 microg/mL) and DPPH scavenging effect (IC(50) 63.2 microg/mL) followed by water extracts (with IC(50) of 287.7 and 73.7 microg/mL, respectively); whereas diethyl ether extracts were the lowest. In the scavenging on superoxide radical assay, methanol extracts obtained the best results (IC(50) 6.9 microg/mL). For all the methods tested the antioxidant activity was concentration dependent. In accordance with antioxidant activity, highest total phenols content were found in ethanol, followed by water, methanol and diethyl ether extract. The results indicated that A. unedo leaves are a potential source of natural antioxidants.
CIMO/Escola Superior Agrária, Instituto Politécnico de Bragança, Campus Sta Apolónia, Apartado 1 172, 5301-855 Bragança, Portugal.
Ivo
I
Oliveira
Valentim
V
Coelho
Raquel
R
Baltasar
José Alberto
JA
Pereira
Paula
P
Baptista
D001713:Biphenyl Compounds / Q000737:chemistry; D029791:Ericaceae / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D005609:Free Radicals / Q000737:chemistry; D007202:Indicators and Reagents; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D012997:Solvents; D013481:Superoxides / Q000737:chemistry
D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D005609:Free Radicals; D007202:Indicators and Reagents; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D012997:Solvents; D013481:Superoxides; C004931:1,1-diphenyl-2-picrylhydrazyl