Comparative in vitro bioactivities of tea extracts from six species of Ardisia and their effect on growth inhibition of HepG2 cells

Aim of the studyArdisia species, notably A. compressa, are used in some regions of the world as food or in traditional medicine for prevention and treatment of certain health conditions including liver disease. We investigated the chemical composition and relative anticancer potential of six Ardisia species [A. japonica (AJ), A. escallonioides (AES), A. mamillata (AM), A. compressa (AC), A. crenata (ACR), and A. elliptica (AE)].Materials and methodsAntioxidant capacity, DNA human topoisomerase II catalytic inhibition, and cytotoxicity on human liver cancer cells (HepG2) were determined in vitro in tea extracts of the 6 Ardisia species evaluated. Selected pure phenolic compounds present in Ardisia species were also evaluated.ResultsAC showed the highest topoisomerase II catalytic inhibition (IC50 = 12 μg/ml) and cytotoxicity (IC50 = 117 μg/ml) against HepG2 cells, followed by ACR and AJ. Total polyphenols ranged from 21 to 72 mg equivalents of gallic acid (GA)/g solid extract (SE). LC–MS analysis revealed the presence of GA, quercetin derivatives, ardisenone, ardisiaquinone, ardisianone, bergenin, norbergenin, and embelin. However, neither total polyphenol concentration nor antioxidant capacity correlated with anticancer capacity. Significant HepG2 cytotoxicity was also achieved by bergenin (IC50 = 18 μM) and embelin (IC50 = 120 μM). AC, bergenin, embelin, and quercetin showed a tendency to accumulate cells in the G1 phase and reduced G2/M leading to apoptosis.ConclusionsAlthough the mechanism is not entirely clear, AC, ACR, and AJ are the Ardisia species with the greatest anticancer potential against liver cancer cells in vitro and deserve further investigation.

Graphical abstractArdisia species from around the world.Figure optionsDownload full-size imageDownload as PowerPoint slide