Isolation of utero-evacuant substances from plant extracts

#In co-pending application Ser. No. 547,415, filed Feb. 6, 1975, now abandoned, there is described a method of isolating and purifying extracts of the zoapatle plant which leads to purified compounds having useful biological activity. The method involves chromatography of the crude material through a column of adsorbent material followed by chromatography through a column of an organic polymeric gel. The present invention relates to a method of isolating and purifying the biologically active materials present in the zoapatle plant which comprises acylating semi-purified material obtained from the crude plant extract and separating the acylated derivatives by physical means. The acyl moiety may then be removed to obtain the biologically active plant ingredients as pure substances. Both the acylated and underivatized materials possess biological activity.

#The zoapatle plant is a bush about 2 m. high that grows wild in Mexico. Botanically it is known as Montanoa tomentosa according to Cervantes, Fam. Compositae, Tribe Heliantheae; another variety of the species is Montanoa floribunda. The plant is described in great detail in Las Plantas Medicinales de Mexico, third edition, Ediciones Botas (1944).

#The plant has been used for centuries in the form of a "tea" or other crude aqueous preparations primarily as a labor inducer or menses inducer for humans. Its use has been documented in the literature, but definitive chemical and pharmacological studies have not been performed.

#The semi-purified material used as the starting material (0.5 g.) is dissolved in pyridine (6 ml.) and treated while stirring at room temperature with acetic anhydride (3 ml.) under an atmosphere of nitrogen for 18 hrs. The pyridine is removed in vacuo, the residue is treated with methanol and the methanol is removed. The residue (0.522 g.) obtained following removal of the methanol in vacuo is chromatographed on a column of silicic acid (50 g.) packed in cyclohexane and eluted with an increasing gradient of ethyl acetate in cyclohexane, collecting 25 ml. fractions. The less polar substance is eluted with 50:50 ethyl acetate:cyclohexane. The fractions containing the less polar substance are combined to afford 63 mg. of a material (IIb) having the following spectral characteristics:

#IIb, ir (neat).mu.: 5.75, 5.95, 6.2, 8.1; nmr (CHCl.sub.3).delta.1.0, 1.11, 2.03, 4.08, 4.56, 4.62, 5.2-5.5, 6.03.

#The more polar substance is eluted with 60:40 ethyl acetate:cyclohexane. The fractions containing the more polar substance are combined to afford 100 mg. of a material (Ib) having the following spectral characteristics: