Systematic investigation of phenolic compounds distribution in Libidibia ferrea (ironwood) seedling, using metabolomics and histochemical techniques.

Ironwood (Libidibia ferrea) is cultivated and widely used due to its medicinal properties attributed especially to phenolic compounds. In the seedling stage, different environmental conditions influence the synthesis, composition, and accumulation of bioactive compounds in different ways, mainly under water stress. Thus, given the wide distribution, this study aimed to analyze the occurrence and distribution of phenolic compounds in L. ferrea seedling for three different states/climate typologies: Pará/Af, Amazonas/Am, and Maranhão/Aw. Gas chromatography-mass spectrometry (GC-MS) and plantlet histochemistry were applied to determine the phenolic compounds distribution present in the extracts of leaflets and roots, respectively. Three different metabolic profiles were described, of which Pará/Af and Maranhão/Aw were similar, while Amazonas/Am showed quantitative differences in the composition. Among the main phenolic compounds were found gallic acid, ferulic acid, and caffeic acid, and presented different concentrations according to origin. The only phenolic compound found for all origins was gallic acid. Therefore, it was demonstrated that the chemical profile of phenolic compounds is conserved in L. ferrea, and significant variations were not observed, which ensures the use of this species regardless of origin.