A simple method for extracting plant phenolic compounds

Abstract

Quantitative estimation of phenolic compounds in plant tissues remains uncertain, mainly because those substances are unstable and easily degradable. In this research we have developed and tested a new method for extracting phenolic compounds from sugar maple (Acersaccharum Marsh.) leaves. The research involved three steps: (i) various procedures currently used for extraction of phenolic compounds were tested with five pure phenolic acids; (ii) the extraction solvent, the procedure for dissolving the phenolic compounds, the temperature, and the duration of the treatment were tested on maple leaves; (iii) two methods that were found equally efficient for litter maple leaves were tested on maple leaves collected in June, on barley leaves, and on four pure phenolic acids. Based on those tests, the dissolution of phenolic compounds in 50% aqueous ethanol (v/v) at 40 °C for 3 h appeared to be the most reliable and the least destructive method. We also recommend the use of Polyclar AT, a resin that retains phenolics in solution, to assess the amount of reductive nonphenolic substances present in the plant material analyzed.