As part of a program to isolate estrogenic compounds from botanicals used in Chinese
Medicines, rhizomes of Anemarrhenae asphoeloides (Liliaceae), Chinese name “Zhi Mu”, was subjected to activity-guided isolation to
afford a series of norlignans. Anemarrhena has been recorded in the Divine Farmers Materia Medica, the first Chinese pharmacopeia
circa 200AD. In Chinese herbal medicine Anemarrhena is commonly used for fever with thirst, dry cough and sensation of dryness like in
diabetes. The isolated compounds were assayed for their estrogenic activity using
transient transfection assays in the human U2OS bone cell line transiently transfected
with either estrogen receptor alpha (ERα) or ERβ and an estrogen response element
linked to the luciferase reporter gene (ERE-tkLuc). One of the identified compounds,
nyasol is a selective estrogen receptor beta agonist. Nyasol inhibits the growth of
MCF-7 breast cancer cells in vitro. It acts as an anti-inflammatory agent by repressing the activation of cytokines
such as TNFα and IL-6 via ERβ. Nyasol inhibits breast cancer tumor formation in mouse
xenograft models. 2.5 mg of Nyasol in a subcutaneous osmotic pump did not increase
uterine weight in mice after 30 days. Given this profile, nyasol may be useful for
the treatment of various gynecologic disorders without increasing the risk for cancer
seen with natural estrogen.
