© 2018 Al-Harrasi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The distribution and biosynthesis of boswellic acids (BAs) is scarce in current literature. Present study aims to elucidate the BAs biosynthetic and its diversity in the resins of Boswellia sacra and Boswellia papyrifera. Results revealed the isolation of new (3β, 11β-dihy-droxy BA) and recently known (as new source, β-boswellic aldehyde) precursors from B. sacra resin along with α-amyrin. Following this, a detailed nomenclature of BAs was elucidated. The quantification and distribution of amyrins (3-epi-α-amyrin, β-amyrin and α-amyrin) and BAs in different Boswellia resins showed highest amyrin and BAs in B. sacra as compared with B. serrata and B. papyrifera. Distribution of BAs significantly varied in the resin of B. sacra collected from dry mountains than coastal trees. In B. sacra, high content of α-amyrin was found in the roots but it lacked β-amyrin and BAs. The leaf part showed traces of β-ABA and AKBA but was deficient in amyrins. This was further confirmed by lack of transcript accumulation of amyrin-related biosynthesis gene in leaf part. In contrast, the stem showed presence of all six BAs which are attributed to existence of resin-secretory canals. In conclusion, the boswellic acids are genus-specific chemical constituents for Boswellia species albeit the variation of the amounts among different Boswellia species and grades.
Al-Harrasi, A., Rehman, N. U., Khan, A. L., Al-Broumi, M., Al-Amri, I., Hussain, J., … Csuk, R. (2018). Chemical, molecular and structural studies of boswellia species: Β-boswellic aldehyde and 3-epi-11β-dihydroxy ba as precursors in biosynthesis of boswellic acids. PLoS ONE, 13(6). https://doi.org/10.1371/journal.pone.0198666