Effect of St. John's Wort standardized extract and hypericin on in vitro placental calcium transport

Hypericum perforatum L., known as St. John's wort (SJW), is widely used in human therapeutics for wound healing and to treat depression; however, its recommendation during pregnancy is controversial. Hypericin, a polycyclic quinone isolated from this plant, has been studied and used to standardize the plant extracts. The objective of the present study was to examine the effect of SJW and hypericin on in vitro placental Ca(2+) transport. Cell viability, human chorionic gonadotrophin (hCG) production, Ca(2+) uptake, and Ca(2+) transport proteins expression analysis were conducted using the JEG-3 cell line. Toxicity of SJW was seen at high concentrations (>or=150 microg/mL), but no effect on hCG production was observed using SJW (25 microg/mL) or hypericin (7.5 and 75 ng/mL). The results showed that cells treated with both SJW and hypericin exhibited increased intracellular Ca(2+) concentration after long-term (24-hour) but not short-term (10-minute) period incubation. A significant decrease in translationally controlled tumor protein Ca(2+) handling protein was seen only with SJW-treated cells. Hypericin increased the protein expression of the transient receptor potential vanilloid 6 Ca(2+) channel and 28-kDa calcium-binding protein and decreased that of plasma membrane Ca(2+)-ATPase 1/4. In conclusion, SJW and hypericin can increase the trophoblast internal Ca(2+) concentration through regulating the protein expression of the Ca(2+) transport system, and their intake during pregnancy is still a point of concern.