Analysis of Naturally Occurring Phenolic Compounds in Aromatic Plants by RP-HPLC Coupled to Diode Array Detector (DAD) and GC-MS after Silylation.

Charalampos Proestos,Michael Komaitis

doi:10.3390/foods2010090

Abstract

The following aromatic plants of Greek origin, Origanum dictamnus (dictamus), Eucalyptus globulus (eucalyptus), Origanum vulgare L. (oregano), Mellisa officinalis L. (balm mint) and Sideritis cretica (mountain tea), were examined for the content of phenolic substances. Reversed phase HPLC coupled to diode array detector (DAD) was used for the analysis of the plant extracts. The gas chromatography-mass spectrometry method (GC-MS) was also used for identification of phenolic compounds after silylation. The most abundant phenolic acids were: gallic acid (1.5–2.6 mg/100 g dry sample), ferulic acid (0.34–6.9 mg/100 g dry sample) and caffeic acid (1.0–13.8 mg/100 g dry sample). (+)-Catechin and (−)-epicatechin were the main flavonoids identified in oregano and mountain tea. Quercetin was detected only in eucalyptus and mountain tea.

Highlights

IntroductionPhenolic compounds are almost ubiquitous in plant foods (cereals, vegetables, fruits, legumes, nuts, etc.) and beverages (wine, beer, tea, cocoa, cider, etc.) [1]
Phenolic compounds are almost ubiquitous in plant foods and beverages [1]
Hydrolysis of glycosides or esters was necessary, so as to determine phenolic content by high performance liquid chromatography (HPLC), since a considerable fraction is in bound form [8]

Summary

Introduction

Phenolic compounds are almost ubiquitous in plant foods (cereals, vegetables, fruits, legumes, nuts, etc.) and beverages (wine, beer, tea, cocoa, cider, etc.) [1]. Their levels vary greatly even between cultivars of the same species. The presence of polyphenols in plant foods is largely influenced by genetic factors and environmental conditions Other factors, such as germination, degree of ripeness, variety, processing, and storage, influence the content of plant phenolics [3,4]. Flavonoids represent the most common and widely distributed group of plant phenolics Their common structure is that of diphenylpropanes (C6C3C6) and consists of two aromatic rings linked through three carbons that usually form an oxygenated heterocycle

Methods

Results

Conclusion