Figure 1.

Chemical structures of 5,6-dehydrokawain; DK (A), dihydro-5,6-dehydrokawain; DDK (B) and 8(17),12- labdadiene-15,16-dial; labdadiene (C).

Chemical structures of 5,6-dehydrokawain; DK (A), dihydro-5,6-dehydrokawain; DDK (B) and 8(17),12- labdadiene-15,16-dial; labdadiene (C).