Phenolic constituents of Hypericum triquetrifolium Turra (Guttiferae) growing in Turkey: variation among populations and plant parts

Abstract

Hypericum triquetrifolium Turra (Guttiferae) has received considerable scientific interest in recent years, as it is a source of a variety of biologically active compounds including phenolics. The present study was conducted to determine the variation in the content of several phenolics, namely phenylpropane chlorogenic acid and flavonoids such as rutin, hyperoside, apigenin-7-O-glucoside, kaempferol quercitrin, quercetin and amentoflavone among four H. triquetrifolium populations from the Central Black Sea Region of Turkey. The aerial parts representing a total of 30 shoots were collected at full flowering in each population. After drying at room temperature, they were dissected into floral, leaf and stem tissues and subsequently assayed for phenolic compounds by HPLC. The populations varied significantly in phenolic content. Among different plant parts, the flowers were found to be the principle organ for chlorogenic acid, hyperoside, apigenin-7-O-glucoside, kaempferol, quercetin and amentoflavone accumulations, while rutin and quercitrin were accumulated mainly in the leaves. The presence of apigenin-7-O-glucoside and amentoflavone in H. triquetrifolium is reported by us for the first time. The chemical variation among the populations and plant parts is discussed as being possibly the result of different genetic, environmental and morphological factors.