Echinacea purpurea flower extracts and cichoric acid inhibit growth of HCT‐116 cells through downregulation of hTERT mRNA expression, telomerase activity and induces G1 cell cycle arrest

Abstract

This study evaluated the effects of ethanol and extraction temperature on the quality of freeze‐dried Echinacea purpurea flowers. The inhibitory effects of flower extract and cichoric acid on human colonic HCT‐116 cancer cells growth were also examined. The optimal extraction conditions for freeze‐dried flowers were 50% ethanol and 65¢XC extraction temperature, with extraction yield of 37.4%. Total phenolics, total caffeic acid derivatives, and cichoric acid contents in freeze‐dried extracts were 473.34, 302.20 and 217.61 mg/g, respectively. MTT (3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay showed that the growth of HCT‐116 cells was inhibited by flower extract and cichoric acid in dose‐ and time‐dependent manners. Cichoric acid treatment also inhibited the expression of hTERT mRNA and telomerase activity. Cytometric analyses showed that cichoric acid caused G1‐phase arrest within 24–48 h. Thus, the 50% ethanol extract of Echinacea purpurea flowers and cichoric acid could be used as a potential therapeutic agent against colon cancer.