## 3 Results and Discussion
It is considered a precursor of many sesquiterpene hydrocarbons such as cadinane, eudesmane (selinane), oppositane, axane, isodoacane, and bourbonane [21] and is one of the _Vitis vinifera_ L. sesquiterpenoids reported to occur in grapes, both red and white varieties [10]. Among the byclic sesquiterpenes, \(\alpha\) and \(\beta\)-selinene and \(\gamma\)-eudesmol were identified. They are bicyclic eudesmane sesquiterpenes which are thought to be derived from further cyclization of the monocyclic germacranes. \(\beta\)-Selinene and \(\gamma\)-eudesmol were identified as traces in Petit Verdot and Sagrantino, respectively, while \(\alpha\)-selinene in Merlot, Barbarossa and Sagrantino. Valencene was identified, too. Valencene is a volatile sesquiterpene emitted from flowers of grapevine, _Vitis vinifera_ L., this compound has the eremophilane skeleton which derives from the eudesmane skeleton by migration of the C-10 methyl group to C-5 [22]. The highest amount resulted in Syrah and Petit Verdot. The murolane/cadinane group of bicyclic sesquiterpenes were represented only by \(\alpha\)-muvrolene and \(\delta\)-cadinene. In the cadinane skeleton, the decalin ring is trans-fused (1a,6\(\beta\),7\(\beta\)), while in the murolane skeleton (1\(\beta\),6\(\beta\),7\(\beta\)) it is cis-fused. \(\alpha\)-Muurolene and \(\alpha\)-cadinene were reported in different wines and grapes [10, 16]. \(\alpha\)-Muurolene was present in all the wine samples analysed with the highest amount in Syrah and Malbec and the lowest in Sagrantino. \(\delta\)-Cadinene was identified only in Nero d'Avola, Syrah, Merlot and Frappato but in low amount. Among bycicic sesquiterpenes \(\gamma\)-gurjunene was identified only in Syrah wines. It is a guaiene sesquiterpene which contain fused 5 and 7 membered rings. Guaianes are often present together with eudesmanes and may be derived by an alternative cyclization of the same germacrane precursor which gives rise to eudesmanes [23]. \(\alpha\)-Gurjunene, \(\alpha\)-aromadendrene and viridiflorol, aromadendrane sesquiterpenes, are 6,11-cycloguaianes in which an additional cyclopropyl ring has been formed by further cyclization of a guaiane precursor. \(\alpha\)-Gurjunene was identified in Syrah, Nero d'Avola, Frappato and Petit Verdot wines, \(\alpha\)-aromadrendrene in Refosco and viridiflorol in Nero d'Avola. Aromadendrene has been already identified by other Authors in Cabernet Sauvignon wine [11]. Among guaine derivatives, rotundone was not present in the wine samples analyzed. This sesquiterpene ketone is considered responsible for the peppery character of Syrah wines and it has been reported to be present in Australian Syrah wines in an amount ranged between 0.029 and 0.15 \(\mu\)g L\({}^{-1}\)[24]. Rotundone concentration in musts and wines may depend on several factors such as cultivar, region and mesoclimate; in particular, lower temperatures may result in increased rotundone accumulation [25,26], in fact [PERSON], studying the key aroma compounds in Syrah wine, found the lowest value for rotundone (0.001 \(\upmu\)g/L) in warm grape-growing region in South Australia [27]. The GC-MS conditions applied in this research were able to detect compounds up to 2500 LRI value. The LRI reported in literature for rotundone is 2280 [24], consequently if rotundone was present in our samples it would be in a very low amount (below the limit of detection) in agreement with the demonstrated effects of climate on rotundone accumulation since the Syrah wines analyzed came from the Mediterranean area. \(\upalpha\)-Cedrene (cedrane skeleton) is a tricyclic sesquiterpene typical of the cedarwood oil [11], already reported in Cabernet Sauvignon [28]. Among the analyzed samples it was identified as traces only in Petit Verdot wines. From the Table 3, qualitative and quantitative differences resulted among the analyzed wines.