## 4 Sources of Coumarins
It reflects the influence of some well-known factors, such as the geographical origin and the single tree [124; 139; 143; 144; 145; 146; 147; 148] and the wood age [149; 150; 151], as well as the analytical methods used in their quantification. Details on the last topic are addressed in Section 5. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Source** & **Species’ Country of Origin** & **Compound** & **Mean Content** & **References** \\ \hline Oak & & scopoletin & 425 ug/L & [38] \\ _Quercus alb L._ & & scopoletin & 25.15 ug/g DW & [124] \\ _Quercus lyntata_ & & umbelliferone & 0.007–0.025 ug/g & [124] \\ _Quercus stellata_ & & aesculetin & 1.45 ug/g FW & [138] \\ Wanghen & & & \\ \hline Chestnut & Portugal & scopoletin & 1.07 ug/g DW & [124] \\ _Castanae sativa Mill._ & & umbelliferone & nd & \\ \cline{2-5}  & France & scopoletin & 6.73–16.7 ug/g FW & [141] \\ \hline Cherry & Spain & scopoletin & 18.8 ug/g FW & [142] \\ _Prunus avium L._ & Serbia & aesculetin & 102.30 ug/g FW & [139] \\ \hline Myrobalan plum & Serbia & aesculin & 1.87 ug/g FW & [139] \\ _Prunus cerasifera [PERSON]_ & & Serbia & aesculin & 2.31 ug/g FW & [139] \\ \hline Mulberry & Serbia & aesculetin & 29.15 ug/g FW & [139] \\ _Morus alba L._ & & aesculetin & 29.15 ug/g FW & [139] \\ \hline Amendoim & & scopoletin & 0.007 mg/L & [43] \\ _Pterogynte_ & & coumarin & 0.067 mg/L & [43] \\ \hline Cabreiva-parda & & scopoletin & 0.018 mg/L & [43] \\ _Myracarpus frandosus_ & & coumarin & 0.050 mg/L & [43] \\ \hline Canela-Sassafras & & scopoletin & 0.028 mg/L & [43] \\ _Octoa pretiosa_ & & coumarin & 0.011 mg/L & [43] \\ (Vell.) Rohwer & & & \\ \hline Jatobá & & scopoletin & nd & \\ _Hymenae courharil L._ & & coumarin & 9.15 mg/L & [43] \\ \hline Pequi & & scopoletin & nd & \\ _Caryocar brasiliense_ & & coumarin & 0.071 mg/L & [43] \\ \hline Castanheira & & scopoletin & nd & \\ _Bertholletia excelsa_ & & coumarin & 0.007 mg/L & [43] \\ Humb. \& Bonpl. & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 16: Chemical structure of the most prevalent coumarins in wood used for the ageing of spirit beverages. Nevertheless, scopoletin was the most plentiful compound in the majority of the wood types examined, followed by umbelliferone, aesculetin and aesculin in the oak wood, and coumarin in the Brazilian kinds of wood. On the other hand, among the oaks, higher levels of scopoletin were found in American oak wood, followed by _Q. robur_ wood, and lower levels were exhibited by _Q. pyrenaica_ wood. Regarding the other species, cherry wood presented an intermediate scopoletin content, while very low concentrations were observed in Portuguese chestnut, amendoim, cabreiva-parda and canela-sassafras, and it was not detected in the remaining species. Umbelliferone was also more abundant in American oak wood; its levels were similar in the other kinds of oak wood, and it was not detected in the other species. Scopoletin and umbelliferone have been reported as chemical markers of oak wood [19; 152]. Aesculetin contents in different oak wood were quite similar, except in _Q. figinea_, which was richer in this compound, and higher contents were associated with cherry wood and mulberry wood from Serbia. Aesculin was quantified in _Q. robur_ and _Q. sessiflora_ wood, which presented lower contents than mulberry and myrobalan plum wood. Finally, the wood from Brazilian species can be classified into three groups, according to the coumarin content: jacba, with the highest amount; pequi, amendoim and cabreiva-parda, with intermediate levels; and canela-sassafras and castanheira, with the lowest content. The effect of the wood type on the concentration of coumarins in the spirit beverages under study is therefore predictable, and will be discussed in Section 6.