Effects of black cohosh on estrogen biosynthesis in hippocampus of non-human primates ex vivo in vitro and in human neuroblastoma cells in vitro

Estrogens have neuroprotective properties. The aim of the study was to assess the impact of an isopropanolic extract of Cimicifuga racemosa (iCR), 17ß-estradiol (E2), testosterone (T) and Tibolone’s 3α-OH metabolite (Org4094) on local estrogen formation in hippocampus tissue from non-human primates ex vivo in vitro and human neuroblastoma cells (SH-SY5Y) in vitro.

SH-SY5Y cells were incubated in RPMI 1640 medium containing 5 % steroid-depleted fetal calf serum for 3 days, and subsequently incubated in absence or presence of iCR at 10 μg/ml (n = 5) and 1 μg/ml (n = 5), E2 at 10⁻⁸ M (n = 5), and 10⁻⁶ M (n = 5), or T at 10⁻⁸ M (n = 5), and 10⁻⁶ M (n = 5), respectively, at 37 °C for either 24 h or directly in cell extracts. Hippocampus tissue from healthy female cynomolgus macaques (n = 14) was homogenized and treated with iCR, E2 and Org4049 accordingly. STS activity was evaluated by incubating homogenized brain cells and tissue with [3H]-estrone sulfate and separating the products estrone (E1) and E2 by thin layer chromatography. STS activity was expressed as total estrogen formation (E1 + E2) fmol/mg of protein/min. Statistical comparisons were made using unpaired T-Test for comparing two sets of data and ANOVA to compare many groups at once. A p value < 0.05 was considered to be significant different.

Local estrogen formation within brain cells and tissue may be modulated by black cohosh, 17ß-estradiol, testosterone, and Tibolone’s 3α-OH metabolite, respectively. The clinical implication of this finding has to be elucidated.