Dehydrocostuslactone and plant growth activity of derived guaianolides

The stereostructures of two new guaianolides, isodehydrocostuslactone and isozaluzanin C, isolated previously from Saussurea lappa, have been confirmed by their correlation with dehydrocostuslactone. Twenty new derivatives have been synthesized from these guaianolides and these have been tested as plant growth regulators. The conjugated lactones which have an exocyclic methylene group at C-4 conjugated with a C-3 ketone, show distinct enhancement in their root-forming potential, as compared with their 3-deoxy derivatives. Of further significance is the fact that these ketones display maximum activity only at lower concentrations. Other compounds show the expected structure-biological activity relationships displayed in general by guaianolides. However, the presence of an epoxide at the C-3, C-4 position does not affect the biological activity, which is indeed the case when the epoxide group occupies the C-4, C-14 position in guaianolides. The major biological parameter studied was rooting in-stem cuttings of Phaseolus aureus.     

Constituents of the essential oils from three tetraploid species of Chrysanthemum

The chemical constituents of the volatile oils from Chrysanthemum indicum, C. yoshinaganthum and C. cuneifolium, three botanically related tetraploid species, are described. By spectroscopic methods, 42 compounds were identified, including 22 monoterpenoids, 17 sesquiterpenoids and 3 acetylenic compounds. The sesquiterpenoids estafiatin (C. yoshinaganthum) and valeranone (C. indicum) have been found for the first time in Chrysanthemum species.     

Isodehydrocostus lactone and isozaluzanin C,two guaianolides from Saussurea lappa

Two new guaianolides have been isolated from Saussurea lappa as minor components and have been named isodehydrocostus lactone and isozaluzanin C. A structure has been assigned to isodehydrocostus lactone on the basis of spectral data and correlation with estafiatin. The ¹H NMR data and dehydrogenation studies show that the other highly crystalline guaianolide is isomeric with zaluzanin C. Earlier 3β-H-zaluzanin C has however been reported to occur as a colourless oil.