Coleus Coleons

Riiedi, P Eugster, C. H. Struktur von Coleon E, einem neuen ditepenoiden Methylenchinon aus der Coleus barbatus-Gruppe (Labiatae). Helv. Chim. Acta 1972, 55, 1994-2014. 

Coleus diterpenoids. Coleus species have been a rich source of highly oxidized spiroabietanes, a number of which have been described recently. Coleons M (36 R = Ac), N (37), P (38), Q [12a-hydroxy-epimer of (38)], and coleon R, which possesses 3a-, 12a-, and 6/8-acetoxy-groups and a 7a-hydroxy-group, have been isolated39 from Plectranthus caninus whereas coleon O (36 R = H) was isolated from Coleus somaliensis. 

Abietanes.—A number of more highly oxygenated abietanes related to the royleanones have been described recently. A new quinone, nemorone (27), has been isolated from the roots of Salvia nemorosa. Coleon C (28) and its tautomer coleon D, which possesses a trans a/b ring junction and a 6,7-diketone in place of the diosphenol on ring b, have been isolated from Coleus aquaticus. These compounds have a very characteristic u. v. spectrum. Lycoxanthol is an ether (29) which has been isolated from Lycopodium lucidulum and which possesses a very similar structure. 

The leaf pigments of Coleus (Labiatae) species continue to be the source of highly oxidized diterpenoids. A group of eleven coleons and royleanones including carnosolone (36) were obtained " from C carnosus and coleon X (37) and the unusual cw-butadiene coleon Z (38) were obtained from Solenostemon... 

Hausen BM, Devriese EG, Geuns JMC (1988) Sensitizing potency of coleon O in Coleus species (Lamiaceae). Contact Dermatitis 19 217-218... 

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