Doris verrucosa

In more recent studies the use of HPLC allowed isolation and counting of individual sterols after administration of labelled precursors. The sterols isolated from mantles and viscera of the nudibranch Doris verrucosa were identified as cholestanol, cholesterol, 24-dehydrocholesterol and 7-dehydrocholesterol [103]. After injection of dl-[2-14C]-mevalonic acid DBED salt, cholesterol (57) and 7-dehydrocholesterol (58) were isolated as the acetates by reversed phase HPLC. Both sterols were found significantly labelled specific radioactivity associated with 7-dehydrocholesterol was higher by one order of magnitude than that associated with cholesterol. This fact would indicate either that the reduction of the A1 double bond of 7-dehydrocholesterol to afford cholesterol occurs at a low rate, or that the cholesterol found in D. verrucosa comes partly from a dietary source. 

Extracts of the digestive gland of the nudibranch Doris verrucosa contained the unusual xyloside, 9-(5-deoxy-5-methylthio-P-D-xylofuranosyl)adenine (206), identified by comparison with synthetic material [213]. 

Gavagnin M, Ungur N, Castelluccio F, Cimino G (1997) Novel Verrucosins from the Skin of the Mediterranean Nudibranch Doris verrucosa. Tetrahedron 53 1491... 

Avila, C., Ballesteros, M., Cimino, G., Crispino, A., Gavagnin, M., and Sodano, G., Biosynthetic origin and anatomical distribution of the main secondary metabolites in the nudibranch mollusc Doris verrucosa, Comp. Biochem. Physiol., 97B, 363, 1990. 

Another dorid nudibranch, Doris verrucosa has been reported (70) to contain an analogue of methylthioadenosine [84] along with diterpenoic acid glycerides, verrucosin A [85] and verrucosin B [86]. The carbon skeleton of the vemicosins could be derived from isocopalane diterpenes which formerly were considered to be the biogenetic precursors of the tetracyclic spongiane diterpenes. 

C11H15N5O3S 297.337 Isol. from the mollusc Doris verrucosa. Glass. 

Cimino, G., Gavagnin, M., Sodano, G Puliti, R., Mattia, C.A., and Mazarella, L. (1988c) Vermcosin-A and B, ichthyotoxic diterpenoic add glycerides with a new carbon skeleton from the dorid nudibranch Doris verrucosa. Tetrahedron, 44, 2301—2310. 

Fontana, A., Tramice, A., Cutignano, A., d lppohto, G., Renzulli, L and Cimino, G. (2003b) Studies of the biogenesis of verrucosins, toxic diterpenoid glycerides of the Mediterranean mollusc Doris verrucosa. Eur J. Org. Chem., 3104—3108. 

Gavagnin, M Ungur, N., Castellucio, E., and Cimino, G. (1997a) Novel verrucosins from the skin of the Mediterranean nudibranch Doris verrucosa. Tetrahedron, 53,1491-1504. 

Biosynthetic studies involving the incorporation of G-and -labeled precursors have shovm that many species of nudibrandis are capable, de novo, of synthesizing diterpenic glycerides. Recent biosynthetic studies involving incorporation of [U- C] glucose in Doris verrucosa showed that the nudibranch synthesizes verrucosins de novo (Fontana et al, 2003b). 

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