HPLC determination of polyphenols of the flowers of Digitalis lamarckii, Xeranthemum annuum, Epilobium hirsutum and Silene compacta from Bolu (Turkey)

Abstract

There have been a growing interest since decades in the medicinal plants in terms of preventive health care and treatment of various diseases. On the other hand, polyphenolic compounds present in medicinal plants are known to have antioxidant potency. In the current work, the quantitative HPLC analysis of the flowers of four plants grown in Bolu-Turkey, Silene compacta, Digitalis lamarckii, Xeranthemum annuum L., and Epilobium hirsutum L was carried out. Prior to HPLC quantification, they were detected by TLC with reference standard compounds, identified by LC-MS and compared for their profiles of phenolic acids and some flavonoids by using high-performance liquid chromatography (HPLC) with diode array detector. The highest contents of benzoic acids were detected in the flowers of E. hirsutum L. as 159 mg in 100 g dry flowers. As for cinnamic acids, the highest content value was found in S. compacta flowers  as 292 mg in 100 g dry flowers. On the other hand, E. hirsutum L. flowers contained the highest total flavonoid value as much as 3890 mg. Total polyphenolic content was the highest (4104 mg/100 g dry plant) in E. hirsutum L., however, the lowest value was found as 492 mg/100 g dry flowers for D. lamarcki. Key words:  Polyphenols,  HPLC,  LC-MS,  quantitative determination, Silene compacta, Digitalis lamarckii, Xeranthemum annuum L., Epilobium hirsutum L.