# Forest Volatile Organic Compounds and Their Effects on Human Health: A State-of-the-Art Review
## 3 Results
### Pintenes
A clinical trial involving patients with bronchitis tested a product containing \(\alpha\)-pinene, D-limonene, and 1,8-cineole, and, although study results were positive [140], if we consider the clinically recognized effects of 1,8-cineole on bronchitis, it is impossible to discern whether \(\alpha\)-pinene was important for the results. A single-blind clinical trial on pediculosis tested two essential oils, one of _Eucalyptus globulus_ and one of _Cinnamomum zeylanicum_, both containing \(\alpha\)-pinene, and found eucalyptus oil to be superior to permethrin [141], while a second study evaluated the effects of essential oil obtained from the leaves of _Lipia multiflora_ and found it to be superior to benzyl benzoate [142]. In both cases, however, given the recognized significant activity of 1,8-cineole and terpineol, respectively, on pediculosis, it is impossible to declare pinene as an active and useful compound per se. The reviewed trials on memory and Alzheimer's disease tested only whole essential oils belonging to the genus _Salvia_ (_Salvia officinalis_ and _Salvia laroundulaefolia_) for their inhibitory activity on cholinesterase [143, 144, 145]. Again, as previously noted, these essential oils contain, apart from pinene, several compounds, and, in fact, 1,8-cineole is likely to be the most active molecule, although a synergistic interaction with other monoterenes has been suggested. Amongst pharmacological effects of pinenes demonstrated on the basis of preclinical evidence, authors of the previously mentioned review specifically analyzed those relevant to cancer growth, allergies, inflammation, infections, and anxiety [23]. Data about cancer cells suggest that \(\alpha\)-pinene might have effects on NF-\(\kappa\)B and I\(\kappa\)B\(\alpha\), and, therefore, on inflammation, mitochondrial functions, ROS production, caspase-3 activity, and DNA fragmentation [146], but also on efflux pumps responsible for multidrug-resistant tumors [147], as well as on cell cycle arrest via the cyclin-B protein [148]. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Plant Source** & **Botanical Family** & **Part of the Plant Used** & **Content (\%) \({}^{*}\)** \\ \hline _Abies alba Mill._ & Pinaceae & Cones & 3.0–22.5 \\ \hline _Abies bulsamen_ L. & Pinaceae & Leaves and twigs & 28.1–56.1 \\ \hline _Picea abies_ (Mill.) [PERSON] & Pinaceae & Leaves and twigs & 4.8–31.9 \\ \hline _Picea glauc_ (Moench) [PERSON] & Pinaceae & Leaves and twigs & 23.0 \\ \hline _Pinus mugo_ [PERSON] & Pinaceae & Leaves and twigs & 1.3–20.7 \\ \hline _Pinus ponderosa_ Douglas ex P. & & & \\ [PERSON] \& C. [PERSON] & Pinaceae & Leaves and twigs & 28.9 \\ \hline _Pinus resinosa_ Ait. & Pinaceae & Leaves and twigs & 29.4–29.9 \\ \hline _Pinus strobus_ L. & Pinaceae & Leaves and twigs & 31.1–33.3 \\ \hline _Pinus sylvestris_ L. & Pinaceae & Leaves and twigs & 1.9–33.3 \\ \hline _Tsuga canadensis_ (L.) [PERSON] & Pinaceae & Leaves and twigs & 20.8 \\ \hline _Citrus x aurantifolia Christm._ & Rutaceae & Fruit peel & 21.1 \\ \hline \hline \multicolumn{4}{l}{\({}^{*}\)Content (\%) = the relative quantity, expressed as a range of percentages, of \(\beta\)-pinene included in tree-derived essential oils.} \\ \end{tabular}
\end{table} 
Table 7: Tree species whose total essential oil contains more than 20% of \(\beta\)-pinene [106]. A pre-treatment of allergic rhinitis models with \(\alpha\)-pinene resulted in a significant reduction in clinical symptoms and inflammatory cytokine levels [149]. \(\alpha\)-pinene also appears to exert moderate antimicrobial [150; 151] and immune-modulating effects [61; 62]. Finally, it has been shown that \(\alpha\)-pinene binds to the GABA-A receptor, at the benzodiazep binding site, thus prolonging GABAergic inhibitory signaling and suggesting an anxiolytic and sleep-enhancing effect [91]. A summary of preclinical evidence of \(\alpha\)-pinene biological activity has been reported in Table 8.