Menerba

Menerba, also known as Menopause Formula 101 (MF-101), is a botanical drug candidate that acts as a selective estrogen receptor modulator (SERM) which is being studied for its potential to relieve hot flashes associated with menopause. Menerba, an estrogen receptor beta (ERβ) agonist (ERBA), is part of a new class of receptor subtype-selective estrogens, which is selective in transcriptional regulation to one of the two known estrogen receptor (ER) subtypes. Menerba consists of 22 herbs that have been used historically in traditional Chinese medicine.

Menerba binds to both ERα and ERβ and with equal affinity, but does not activate ERα and instead activates only ERβ-mediated gene transcription.

Mode of action

Menerba has been reported to alleviate menopausal symptoms such as hot flashes, while having no stimulative effects on endometrium or breast tissue.

In mouse xenograft models, Menerba produced a different conformation in estrogen receptor alpha (ERα) from ERβ when compared with the conformations produced by estradiol. The specific conformational change induced by Menerba allows ERβ to bind to an estrogen response element and recruit coregulatory proteins that are required for gene activation. It has been shown that the increased risk of breast and uterine cancers is associated with ERα activation and that ERβ blocks the growth promoting effects on breast cancer cells. Menerba does not activate the ERα-regulated proliferative genes, c-myc and cyclin D1, or stimulate MCF-7 breast cancer cell proliferation or tumor formation, demonstrating that it may be a viable alternative for hormone therapy in comparison to estrogens that non-selectively activate both ER subtypes.