Separation and identification of phenolic compounds in Jerusalem artichoke (Helianthus tuberosus L.)

Several methods such as colorimetry, reversed-phase high performance liquid chromatography (RP-HPLC), the coupling of liquid chromatography and gas chromatography with mass spectrometry (LC-MS, GC-MS) were examined for their suitability and applied to the separation, identification and quantification of phenolic compounds in different varieties of Jerusalem artichoke. Twenty two phenolic compounds have been separated, identified and quantitated as gallic acid (from 1 mg up to 140 mg), protocatechuic acid (from 5 mg up to 200 mg), esculin (from 4 mg up to 270 mg), gentisic acid (from 30 mg up to 3 g), catechin (from 1 mg up to 300 mg), 4-hydroxybenzoic acid (from 1 mg up to 90 mg), chlorogenic acid (from 20 mg up to 5 g), vanillic acid (from 1 mg up to 520 mg), syringic acid (from 1 mg up to 40 mg), caffeic acid (from 1 mg up to 240 mg), epicatechin (from 4 mg up to 800 mg), 2-hydroxy-3-5-dinitrobenzoic acid (from 2 mg up to 140 mg), umbelliferon (from 2 mg up to 110 mg), scopoletin (from 1 mg up to 80 mg), p-cumaric acid (from 1 mg up to 40 mg), cumaric-3-carbon acid (from 1 mg up to 40 mg), ferulic acid (from 1 mg up to 40 mg), sinapic acid (from 1 mg up to 60 mg), 3-hydroxycinnamic acid (trace); ellagic acid (from 2 mg up to 40 mg), 4-hydroxycumarin (from 4 mg up to 300 mg) and salicylic acid (from 30 mg to 7 g). These phenolics contents are expressed for 100 g tubers or skins dry weight. Twenty of the identified phenolic compounds are of interest in the medicine and with diets.