Beaver complex scents

If artificial castoreum scent marks are placed on the banks of a pond, beavers, C. canadensis, are more likely to visit, destroy, and re-mark the sites as the complexity of the artificial odor composition increases (Fig. 6.14). While some single phenolics from castoreum such as 4-ethylphenol trigger marking (Miiller-Schwarze and Houlihan, 1991), the response increases as the mixture grows to 4, 6,10,13, and finally 15 compounds. A mixture of 14 phenolics and 12 neutrals (mostly oxygenated monoterpenes) released responses almost as strong as whole castoreum (Schulte etal., 1995). 

The previous review on Nuphar (water-lily) alkaloids in this treatise appeared in Volume 35, and covered the period 1974-1987 (7). It overlapped in part with the treatment of simple bicyclic Nuphar metabolites in Volume 28 (7). Nuphar alkaloids include sesquiterpenoid monomeric (C15) piperidine and quinolizidine alkaloids as well as more complex dimeric (C30) sulfur-containing metabolites. Related metabolites isolated from the scent glands of the Canadian beaver, Castor fiber, also include a unique indolizidine alkaloid 944 606). Only the indolizidine and simple quinolizidine alkaloids are relevant to the present review. Compounds mentioned in the ensuing discussion are illustrated in Fig. 18. 

The original structure of (— )-deoxynupharidine (15) was not correct and much of the earlier literature concerning these alkaloids contains erroneous structures. The compound has a l/ ,4/f,7/f,9a/ configuration, as indicated in Fig. 36.4 (Howard and Michael, 1986). Similar alkaloids have been isolated from the scent glands of the Canadian beaver. Castor fiber (Fig. 36.4). The oil of this gland or castoreum is used as a fixative in the perfumery industry. (— )-Deoxynu-pharidine (15) is one of the components of the complex mixture of compounds found in this oil. Although it is not clear. 

---