Oxepane diterpene

Other compounds isolated from M. tomentosa with potential contraceptive activity are the oxepane diterpenes, zoapatanol and montanol, isolated first in Mexico and then acquired by Ortho Pharmaceuticals. The company pursued their pharmaceutical development extensively in the 1970 s and 1980 s. An extensive review of the effects of zoapatanol and montanol has been published in detail in the literature and is summarized in Table 2 above. A discussion of their effects is out of the scope of this chapter, since these compounds were not found in the aqueous herbal brew [39]. Moreover, montanol appears to be a decomposition product [29]. 

Figure 30. Structures of oxepane diterpenes (55-57, 1097-1099) and their linear precursor-like compounds (1094-1096) reported from Montanoa (Heliantheae).

For hundreds of years, a tea brewed from the leaves of Montanoa tomentosa has been used medicinally to induce labor and as an antifertility agent (419, 382). The M. tomentosa extract possessed abortifacient, labor induction, and menstruation induction effects (572, 297). Zoapatanol (55) appears to be the tea component responsible for most of the activity (368). In addition to zoapatanol, several other oxepane diterpenes (56, 57, 1097, 1098, 1099) and their uncyclized precursors (1094, 1095, 1096) were isolated from this species. Commercial interest in these compounds has led to the synthesis of analogous structures sharing similar pharmacological properties (353). 

Oshima, Y., G.A. Cordell, and H.H.S. Fong Oxepane diterpenes from Montanoa tomentosa, Phytochem. 25, 2567 (1986). 

Quijano, L., and N.H. Fischer Two oxepane diterpene lactones from Melampodium diffusum. Phytochem. 23, 833 (1984). 

Fig. (3). Secondary metabolites from Montanoa lomeniosa include a. Kaurane diterpenes, B. Oxepanes and their acyclic precursors, C. Flavonoids, and D. Guaianolides and heliangolides.

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