Mentha pulegium. European Pennyroyal.
Mentha Pulegium L.—European Pennyroyal. Pouliot commun, Fr. Polei, G. Pulegium vulgare Mill.—This European labiate yields an oil which is known in England as the oil of pennyroyal, and must not be confounded with the American oil of the same name. The oil, which is also known as the oil of poley, has been examined by Beckmann and Pleiasner (Arm. Ch. Ph., 262, 1), who discovered as the most important constituent pulegone, C10H16O, an unsaturated ketone, which makes up 80 per cent. of the oil. It boils under a pressure of 60 mm. at from 54.5° to 55° C. (130°-131° F.), turns the plane of polarization to the right, and has a sp. gr. 0.9323 at 0° C. (32° F.). It forms crystalline compounds with hydroxylamine and with hydrogen bromide. When reduced by sodium in ethereal solution pulegone is. changed into menthol. Pulegone is most abundant in the Spanish oil, and less abundant in American and Algerian oils. (See also Wallach, Ann. Ch. Ph., 272, 122, and Semmler, Ber. d. Chem. Ges., 25, 3515.) Schimmel states that the oil is sometimes adulterated with eucalyptus oil. (Schim. Rep., 1908, 67.) It is stated (B. M. J., March, 1890) that the oil is largely used for the purpose of producing abortion, and is popularly believed to be safer and more certain than the other volatile oils (... the oil of pennyroyal is deadly. For more info see the medicinal herbfaq. -Henriette). Taylor denies, however, that the oil is an abortifacient and it appears to be demonstrated that it is capable of causing fatty degeneration. (See S. Jb., cclxvii, p. 230.)