Objective:To research the effect of 6-hydroxy justicidin A(JR6)on endoplasmic reticulum stress(ERS) and Ca2+ in HepG2 cells. Method: Semiquantitative RT-PCR and Western blot were used to investigate the expression levels of X-box binding protein 1(XBP-1) mRNA

Inositol-requiring enzyme-1α(IRE1α)

Glucose regulated protein/BiP(GRP78/BiP)

B cell leukemia 2(Bcl-2) proteins in HepG2 cells which were treated with 0

0.615

2.45

9.8 μmol·L-1 JR6 separately for 24 h. Laser confocal scanning microscopy was used to study the difference of intracellular calcium between medicine group and IP3R(inositol 1

4

5-trisphos-phate receptor) inhibited group. Result: The expression of IER1

GRP78/BiP Bip

Bcl-2 proteins and XBP-1 mRNA have a reduction in approximately 40% with high JR6 group. It is found that the JR6 could elevate the intracellular calciumion concentration more than two times

and this effect was disappeared with the IP3R inhibitor (Xestospongin C). Conclusion: JR6 through IP3R way elevates intracellular free Ca2+ concentration

and arouse ERS. At the same time

JR6 can inhibit elements which related to unfolded protein response(UPR).