## 3 Results
### Quantitative Analysis of Boswellic Acids  
Eighteen samples of _Boswellia_ gum resin were extracted according to the procedure described in Materials and Methods section. After their analytical preparation the solutions were injected into the HPLC apparatus. The concentration of the 6 chemical species investigated is reported in Table 2.  
In total, 10 gum resin samples were reported by the supplier as _B. carteri_ (7) and _serrata_ (3), 6 samples coming from the African region did not show any information about the botanical species and, finally, 2 samples were purchased without any information about their provenience or species. The 18 analyzed samples show an appreciable diversity in their composition of boswellic acids. It is possible to notice how the KBA concentration is generally higher in _B. serrata_ (2.11 \(\pm\) 0.9% by weight \(n\) = 3) than _B. carteri_ (0.42 \(\pm\) 0.5% by weight \(n\) = 7); on the other hand, AKBA has shown more disperse results in samples of _B. carteri_ (2.44 \(\pm\) 2.9 by weight \(n\) = 7). The samples coming from the African region, but not reporting any further detail about the species, show concentration values of AKBA and KBA which are like the African _B. carteri_ samples: the average content of AKBA is 2.57 \(\pm\) 2% by weight (_n_ = 6) and KBA is 0.35 \(\pm\) 0.4% by weight (_n_ = 6). Finally, the two totally unknown samples report a smaller variation and respective values of AKBA and KBA of 5.45 \(\pm\) 0.22% by weight and 0.49 \(\pm\) 0.2% by weight. A-BA values increase in the _B. serrata_ samples (2.6 \(\pm\) 0.7% by weight \(n\) = 3) as well as B-BA (9 \(\pm\) 1.3% by weight \(n\) = 3), while their acetylated forms are more concentrated in certified _B. carteri_ and the ones for which the \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample ID**} & **Declared** & \multirow{2}{*}{**Provenience**} & \multirow{2}{*}{**\% AKBA**} & \multirow{2}{*}{**\% KBA**} & \multirow{2}{*}{**\% A-BA**} & \multirow{2}{*}{**\% B-BA**} & \multirow{2}{*}{**\% CA-ABA**} & \multirow{2}{*}{**\% CA-ABA**} & \multirow{2}{*}{**\% CA-BBA**} \\  & & & & & & & & \\ \hline
1 & _B. carteri_ & Somalia & 1.43 & 0.09 & 0.36 & 3.6 & 0.43 & 1.58 \\
2 & _B. carteri_ & Somalia & 1.45 & 0.1 & 0.29 & 3.19 & 0.84 & 3.04 \\
3 & _B. carteri_ & Somalia & 1.04 & 0.96 & 0.39 & 4.35 & 0.69 & 2.84 \\
4 & _B. carteri_ & Africa & 0 & 0.06 & 3.24 & 6.72 & 1.7 & 9.73 \\
5 & _B. carteri_ & Africa & 0.47 & 0.12 & 2.55 & 5.95 & 2.86 & 11.8 \\
6 & _B. carteri_ & Somalia & 4.29 & 0.43 & 1.7 & 2.34 & 4.28 & 6.6 \\
7 & _B. carteri_ & Somalia & 8.42 & 1.19 & 1.93 & 3.71 & 2.8 & 7.15 \\ \hline
8 & _B. serrata_ & India & 2.76 & 2.82 & 3.14 & 10.31 & 1.3 & 3.3 \\
9 & _B. serrata_ & India & 2.45 & 2.41 & 2.9 & 7.63 & 1.2 & 3.1 \\
10 & _B. serrata_ & India & 3.62 & 1.1 & 1.74 & 9.07 & 1.1 & 2.3 \\ \hline
11 & unk. & Somalia & 3.89 & 0.41 & 1.97 & 4.94 & 3.55 & 8.92 \\
12 & unk. & Kenya & 0.18 & 0.06 & 2.26 & 5.81 & 3.53 & 14.55 \\
13 & unk. & Africa & 5.63 & 1.08 & 1.08 & 0.78 & 0.6 & 0.07 \\
14 & unk. & Africa & 0.77 & 0.06 & 2.36 & 4.64 & 3.53 & 6.85 \\
15 & unk. & Africa & 0.42 & 0.02 & 3.24 & 5.29 & 3.19 & 5.56 \\
16 & unk. & Africa & 4.58 & 0.47 & 2.11 & 0.917 & 5.8 & 1.6 \\ \hline
17 & unk. & unk. & 5.29 & 0.51 & 1.31 & 3.44 & 3.69 & 2.89 \\
18 & unk. & unk. & 5.61 & 0.47 & 1.76 & 1.98 & 2.62 & 4.94 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Table listing all the samples analyzed in the study with the validated method. Each row reports the sample ID on the first column; declared species reports, for each sample, its species, with “unk” if unknown; provenience reports the national or territorial origin of the sample, with “unk” if unknown. The remaining column reports the concentrations of each boswellic acid studied expressed as weight percentage or g/100 g, and all the observations are an average value of 2 or more analytical repetitions with an RSD value lower than 10%.