Carvone Streptomyces

Flavor of Microbial Transformation Products. The flavor of terpenoids produced by microbial transformation was evaluated. (-)-Carvone (1) is well known as a spearmint flavor component. Transformation products (4 - 7) of 1 had peppermint-like flavor although these are slightly different to each other in terms of the odor quality. The metabolites, bottrospicatols (10a and 10b) Streptomyces species did not have a characteristic flavor but quite different activities (Figure 8). (+)-Bottrospicatal (15) which was produced by the oxidative reaction of (+)-bottrospicatol (10a) with CrOa in pyridine had a weak spice-flavor (slightly black-pepper like). The ester derivatives (13 in Figure 7) had a weak medicinal flavor. The flavor of acetyl ester (13a) was the strongest of all. 

Streptomyces A-5-1 isolated from soil converted (-)-carvone (93 ) to 101a -102d and -)-trans-carveo (81a ). whereasNocardia, 1-3-11 converted (-)-carvone (93 ) to (-)-di-carveol (81b )... 

FIGURE 19.113 Metabolic pathways of (+)- (93) and (-)-carvone (93 ) and dihydrocarveols (102a-d and 102a -d ) by Streptomyces bottropensis SY-2-1 and Streptomyces ikutamanensis Ya-2-1. (Modi ed from Noma, Y., Kagaku to Seibutsu, Tl, 742, 1984.)... 

Noma, Y. and H. Nishimura, 1982. Biotransformation of carvone. 4. Biotransformation of (+)-carvone by Streptomyces bottropensis, SY-2-1. Proceedings of the 26th TEAC, pp. 156-159. 

On the other hand, in Streptomyces, A-5-1 and Nocardia, 1-3-11, which were isolated from soil, (-)-carvone (93 ) was reduced to give mainly -)-trans-car eol (81a ) and (-)-cw-carveol (81b ), respectively. On the other hand, (-)-trani-carveol (81a ) and (-)-cw-carveol (81b ) were dehydrogenated to give 93 by strain 1-3-11 and other microorganisms (Noma et al., 1986). The reaction between trans- and ds-carveols (81a and 81b ) and (-)-carvone (93 ) is reversible (Noma, 1980) (Figure 14.82). 

Effects of (-)-di- (81b ) and (-)-tra 5 -carveol (81a ) conversion products by Streptomyces bottropensis SY-2-1 on the germination of lettuce seeds was examined and the result is shown in Table 14.3. ( f)-Bottrospicatol (92 ) and (-)-carvone-8,9-epoxide (96 ) showed strong inhibitory activity for the germination of lettuce seeds. 

Streptomyces bottropensis SY-2-1 has also different metabolic pathways for (+)-tra 5-carveol (81a) and (-I-) -di-carveol (81b) (Noma and Iwami, 1994). Namely, Streptomyces bottropensis SY-2-1 converted (+)-trans-caiveo (81a) to (-i-)-carvone (93), (-f-)-carvone-8,9-epoxide (96), and (-i-)-5a-hydroxycarvone (98a) (Noma and Nishimura, 1982, 1984) (Figure 14.87). On the other hand, Streptomyces bottropensis SY-2-1 converted (+)-c -carveol (81b) to give (-)-isobottrospicatol (92b) and (+)-5-hydroxy-c -carveol (94b) as the main products and (-)-bottrospicatol (92a) as the minor product as shown in Figure 14.88 (Noma et al., 1980, Noma and Nishimura, 1987 Nishimura and Noma, 1996). 

Metabolic pattern of (4-)-carvone (93) is similar to that of (-)-carvone (93 ) in Streptomyces bottro-pensis. ( f)-Carvone (93) was converted by Streptomyces bottropensis to give (+)-carvone-8,9-epoxide... 

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