Myoporum deserti

Two new toxic sesquiterpenoids, myodesmone (36) and isomyodesmone (37), have been isolated from the essential oils of certain Myoporum species. It has been suggested that these two compounds may be derived from myoporone (38), also found in some specimens of Myoporum deserti, by an in vivo aldolization-dehydration process via the ketol (39). In addition to ipomeamarone (40 R = H), it is reportedthat a new sesquiterpenoid, ipomeamaronol (40 R = OH) also occurs in diseased sweet potato root tissue. 

C15H22O3, Mr 250.34, cryst. (CH3OH), mp. 15.5-16.5°C, [ ]d -7° (CH3OH). Occurs together with the (9/ )-alcohol dihydro-M., C15H24O3, Mr 252.35, oil, [a] -3.6° (CH3OH), as stress metabolite in the sweet potato (Ipomoea batatas) and in the Australian bush Myoporum deserti. M. is hepatotoxic, see also ipomeanine and ipomeamarone. 

Myoporum deserti (Myoporaceae), a widespread Australian shrab, has been responsible for serious livestock losses in that region. These plants cause liver and kidney lesions. Mydesmone (53) is one of the active compounds (Fig. 21.15) (Mabry and Gill, 1979). 

---