Introduction: Menopause occurred caused by the condition of hypo-estrogenic resulting from decreased function of the ovarium. This condition result in the changes of many system and organs of the body. Phytoestrogen is a natural compound that belongs to the plant which was capable of exhibiting estrogenic activity. Coumestrol is a phytoestrogen contained in sesame seeds (Sesamum incidum L).
Aim : To find out binding ability of coumestrol to the estrogen receptor compared with estradiol and to determine estrogenic activity from ethanol extract of sesame seeds (Sesamum indicum L.) using YES assay method.
Method: This research was non-experimental research using computational chemistry based and experimental with randomized block design using YES assay to determine the estrogenic activity of ethanol extract sesame seeds with a series of concentration 50, 100, 200, 400, 800, 1000, 1200, 1600, 2000 μg/mL.
Result: Ligand coumestrol was not on the same binding site pocket with estradiol. The value of energy coumestrol -2,20 kcal/mol where as estradiol -9,55 kcal/mol. Ethanol extract of sesame seeds value EC50 could not calculated, value EC50 positive control estradiol was 1,18x10-4 M and EC50 value from positive control genistein was 7,822x10-15 M.
Conclusion: Coumestrol can not replace estradiol on estrogen receptor. Ethanol extract of sesame seeds have not estrogenic activity.