Comparison of the effects of an aqueous extract of Physalis alkekengi fruits and/or various doses of 17-beta-estradiol on rat estrous cycle and uterine glucose 6-phosphate dehydrogenase activity

Intraperitoneal injections of an aqueous extract of winter cherry fruits (Physalis alkekengi) to adult normal cycling female rats produced 100% diestrus and diminished uterine glucose 6-P dehydrogenase activity (an estrogen-induced protein) by 52%. Daily doses of 1.88, 3.75 and 7.5 mu g 17-beta-estradiol administered intraperitoneally to adult female rats for a period of 6-8 days prolonged proestrus or estrus and increased uterine glucose 6-P dehydrogenase activity by 11.5%, 26.9% and 82.1%, respectively. Combined intraperitoneal injections of a given dose of the aqueous extract together with the above doses of 17-beta-estradiol for 8 consecutive days shortened the time spent in diestrus proportional to the dose employed and proportionately reduced the uterine glucose 6-P dehydrogenase inhibitory power of the aqueous extract (1.88 mu g estradiol, 33.9% inhibition; 3.75 mu g estradiol, 27% inhibition; and 7.5 mu g estradiol, 6.0% activation). The data obtained clearly demonstrate the presence of an estrogen antagonist in the aqueous extract of Physalis alkekengi fruits.