A plant-derived non-estrogenic and non-androgenic alternative to estrogen or androgen replacement therapy

The search for alternatives of hormone replacement therapy (HRT) has resulted in a new market for plant derived substances. The question whether they bear the same benefits and risks as classical estrogens used for HRT remains unanswered. 20-OH-Ecdysone (Ecd) is the molting hormone of arthropods and also produced by a number of plants to prevent herbivori by caterpillars. Ecd has protein anabolic effects and does not bind to estrogen receptor alpha (ER-α) or ER-β.Following a 3 months oral treatment of ovariectomized (ovx) or orchidectomized (orx) rats (53mg/day/animal) it has no stimulatory effects on the uterine or prostate weight and also no effect in the mammary glands of the ovx animals.

When given at doses resulting in nM concentrations in the serum, Ecd is a potent inhibitor of osteoporosis following castration of female and male rats. It also prevents hot flushes in ovx rats as measured by changes of the rat skin temperature. Furthermore a marked effect on fat and muscle tissue was observed: castrated animals gained less fat but more muscle mass under Ecd treatment. In addition it lowers serum cholesterol levels. Taken together these results suggest that Ecd containing plant extracts may be highly effective to replace estrogen and androgen replacement therapy without having the adverse effects of estrogens or androgens in the mammary gland, uterus or prostate respectively. The mechanism of action of Ecd is unknown as Ecd receptors are not expressed in mammalian tissue.