The phytochemical curcumin inhibits steroid sulfatase activity in rat liver tissue and NIH-3T3 mouse fibroblast cells

Curcumin is a phytochemical derived from the spice turmeric that is reported to have therapeutic effects. We are studying the enzyme steroid sulfatase (STS), which removes the sulfate group from inactive steroid hormones in peripheral tissues and we were interested in the effect of curcumin on STS activity due to its structural composition (polyphenolic). We sought to determine if curcumin affects STS activity in two model systems, rat liver and NIH-3T3 mouse fibroblast cells. STS assays were performed on tissue extracts of rat liver, and on NIH3T3 microsomes and cells, with and without curcumin. Male and female rat liver extracts contained substantial amounts of STS activity, with males averaging higher (4-11 %) levels. Estradiol inhibited STS activity in livers of both sexes at 20 and 10 mu M. Curcumin acted as a competitive inhibitor of STS activity in rat liver extracts, with a Ki of 19.8 mu M in males and 9.3 mu M in females. Curcumin also inhibited STS activity in NIH-3T3 microsomes at both 20 mu M and 10 mu M, and in whole NIH-3T3 cells at 20 mu M. These data are the first to demonstrate STS inhibition by curcumin. Inhibition of STS results in lower active steroid hormone (estrogens and androgens) levels in tissues, possibly altering modulation of immune responses by these steroids.

Automated summary

This study found that curcumin competitively inhibits the enzyme steroid sulfatase (STS) in rat liver and NIH-3T3 mouse fibroblast cells, resulting in lower levels of active steroid hormones (estrogens and androgens) in tissues, possibly altering the modulation of immune responses by these steroids.