| Abstract
| - Extracts from Murta leaves are used by Chilean natives for their benefits on health and cosmeticproperties, which are mainly due to the presence of polyphenolic compounds. Extraction of suchcompounds is strongly influenced by several variables, the effects of which are studied in this work;the antioxidant power of the resulting extracts was measured by two different methods [2,2-diphenyl-1-picrylhydrazyl (DPPH) and thiobarbituric acid reactive substances (TBARS)]. On the whole, maximumvalues of polyphenolic yields and antiradical power (DPPH method) were attained at 50 °C (from 25to 50 °C) and a solvent-to-solid ratio (v/w) of 15:1 (15:1−25:1). The solvents assayed were ethanol,methanol, and water. The highest polyphenolic yield values (2.6% expressed as gallic acid) werereached with methanol, whereas maximum EC50 was attained by the ethanol extract (0.121 mol gallicacid/mol DPPH). Contact time was shown to have only a slight influence in alcoholic extraction, whilein water a remarkable effect of increasing contact times (30−90 min)was observed. Just water wasthe solvent that offered the best result when the antioxidant power was measured by the TBARSmethod. High-performance liquid chromatography−mass spectrometry analysis revealed the presenceof polyphenols, basically flavonols and flavanols, sometimes glycosilated; myricetin and quercetinglycosides were detected in all extracts, whereas epicatechin was present in alcoholic extracts andgallic acid was only present in water. Keywords: Murta (Ugni molinae Turcz.); polyphenols; DPPH; TBARS; HPLC-MS
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