Phenolic Compounds in Extracts from Eucalyptus globulus Leaves and Calendula officinalis Flowers

Abstract

Selection of the optimal solvent system for extraction of the phenolics from Eucalyptus globules leaves and Calendula officinalis flowers, determination of the reducing potential and identification of the phenolics in these extracts was performed. The highest content of phenolics was obtained for methanol: water extracts from both sources. All of the Eucalyptus leaf extracts had higher reducing potential than those from the Calendula flowers. Solid-phase purification of the crude extracts removed 57% to 78% of the compounds in the crude extracts. The reducing potential of the purified extracts varied from 0.17 to 2.92 mg caffeic acid/g dry weight. The extracts from Eucalyptus leaves and Calendula flowers both contained chlorogenic acid, rutin and quercetin 3-glucuronide. Ellagic acid derivatives were identified only in the leaves of Eucalyptus, while beside caffeic acid and salicylic acid, quercetin 3-glucuronide, and pinobanksin 3-acetate was found in the Calendula flower extract for the first time.