Effect of Mentha spicata L. Essential Oil Orally Exposure During Organogenesis in Wistar Rats and Development of Fetus Bone

Mentha spicata L. essential oil (MsEO) is consumed in Iranian medicine for pharmaceutical and nutraceutical purposes. No reports are available on MsEO effects on gestation and exposed fetuses as the aim of this study. At gestational days (GD), thirty-five rats were divided into seven groups: control, vehicle, and five MsEO-treated groups. The MsEO groups received the drug at doses of 749.80 (LD1), 904.20 (LD5), 999.10 (LD10), 1180.50 (LD25) and 1420.80 (LD50) mg/kg/day during GD6-15 by gavage. The body weight gain was recorded during gestation. At GD18, the rats were sacrificed and embryos were collected for the study of skeletal malformation. The acute oral LD50 of MsEO was found to be 4417.363 and 1420.796 mg/kg for the first and fifth days, respectively. Fetuses were stained by Alizarin Red-S and Alcian Blue staining method. Relative liver weight increased in MsEO-treated rats as compared to control. The lungs and brain relative weights significantly increased in LD50 group as compared to control. Significantly, the placental efficiency, crown-rump-length (CRL) and the ossification rate increased in LD5 group versus control. MsEO-treated fetuses had no delayed bone ossification. We estimate that a dose of 904 mg/kg body weight of MsEO can increase the rate of fetal skeleton ossification.