Abstract: Heliocarpus terebinthinaceus (Tiliaceae) is a plant native to Central America with a potential as an herbal medicine. The aim of this work was to study the chemical composition of the plant seeds in terms of polyphenolic and flavonoid compounds and the free radical-scavenging capacity of the seed extracts. H. terebinthinaceus seeds can be considered as a good source of Total Polyphenols (TPP) with a content of 1053±18 mg of gallic acid equivalents 100 g-1 of dry matter. The half maximum scavenging concentrations (SC50) of the polar extracts ranged from 1308±23 to 1970±13 μg mL-1. For the chemical elucidation, the ethyl acetate extract was purified using two types of chromatography: silica gel flash column and preparative thin layer. The structural elucidation of the main compound was achieved by 1D and 2D Nuclear Magnetic Resonance (NMR), Infrared (IR) and High Resolution Mass Spectrometry (HRMS). From the structural analyses, the isolated compound was identified as tiliroside. This is the first report on the isolation of tiliroside from plants belonging to the Heliocarpus genus.