Revisiting the leaf anatomy of Hymenaea martiana : new insights from anatomical and histochemical techniques

Hymenaea martiana , known as ‘jatobá', is used in folk medicine and has similarities with Hymenaea courbaril , making its recognition difficult. Although there are different pharmacological reports that attest to its bioactive potential, there are few studies with leaf extracts in H. martiana . And, only one study has investigated the anatomy and histochemistry of the leaves of this species, whose results are limited and may mask the anatomical and secondary metabolite diversity found in the leaves. Therefore, we revisited the anatomy and histochemical profile of H. martiana leaflets using light microscopy to ensure quality control and understand metabolite diversity. For anatomical analysis, the samples were fixed in 50% FAA, sectioned freehand and stained with basic fuchsin/astra blue. For histochemical tests, samples were fixed in FNT, sectioned freehand and subjected to nine tests. It was possible to anatomically distinguish H. martiana from H. courbaril . The diversity of secondary metabolites is related to the presence of phenolic compounds, tannins, alkaloids and lipids and may justify the biological potential of H. martiana leaves. Furthermore, it was found that the structures responsible for the synthesis and secretion of these compounds are: idioblasts, laticifers, channels and secretory cavities. Two of these secretory structures constitute unprecedented reports for the species.