Role of energy metabolism in the pregnancy interceptive action of Ferula assafoetida and Melia azedarach extracts in rat.

Ethanolic extract of Ferula assafoetida and chloroform fraction of Melia azedarach, both devoid of estrogenic activity, were examined for their pregnancy interceptive property. Treatment of rats from days 1 to 7 of pregnancy with either of the plant extracts resulted in pregnancy failure in about 65-85% of the animals. The possible role of energy metabolism in the antifertility action was investigated by measuring changes in activities of the key enzymes of carbohydrate metabolism in uterus on day 7 of pregnancy. It was observed that on the day 7 of pregnancy, one key enzyme of glycolytic pathway (phosphofructokinase) was significantly reduced in the uteri of treated rats as compared to controls. Hexosemonophosphate pathway also appeared to be sensitive to treatment with the plant extracts and showed an inhibitory effect on the enzyme activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Oxidative energy metabolism through tricarboxylic acid cycle, which is considered to be the main source of energy to the uterus at this stage, was maximally affected by the treatment with several enzymes showing significant inhibition. The two plant materials appeared to interrupt the latter metabolic pathway more significantly. It is thus concluded that plants lacking phytoestrogens may intercept pregnancy by their ability to disrupt energy metabolism in rat uterus during implantation, especially the oxidative pathway.