Geographical and environmental influences on Boswellia elongata Balf.f. volatiles: An in situ study on Socotra Island

Frankincense, an esteemed oleo-gum resin derived from Boswellia species (Burseraceae), has been prized by humans for its aromatic, medicinal, and spiritual properties across millennia. Environmental factors play a crucial role in shaping the volatile compound composition of this resin, thereby influencing its quality. In this investigation, we analyzed frankincense sourced from Boswellia elongata Balf.f. at six distinct locations on Socotra Island. Employing thermal desorption-gas chromatography coupled with mass spectrometry (TD-GC/MS), we identified 92 terpenoid compounds, spanning monoterpenes, sesquiterpenes, and diterpenes. Predominant among these volatile organic compounds (VOCs) were α-pinene, γ-terpinene, o-cymene, and (E)-β-farnesene. Multivariate analyses revealed subtle differences in VOC composition, particularly pronounced at the Ma'aleh site, the most geographically isolated research locality. The flowers in this population also displayed distinct red-pink coloration compared to other populations. Integration of VOC data with environmental variables revealed correlations with temperature, elevation, and proximity to the sea, with specific compounds exhibiting associations with distinct environmental contexts. Our findings underscore the impact of microclimatic and abiotic conditions on the volatile profile of individual trees. Moreover, this study offers comprehensive insights into the VOC profile of B. elongata resin and its interplay with environmental factors, thereby suggesting avenues for the cultivation of new varieties or hybridization within the species.