<p>The aim of the present study was to evaluate the chemical composition and antioxidant activity of peel, pulp, and seed of the seriguela fruit at different stages of maturation (unripe, half-ripe, and ripe). The various chemical compositions of carotenoids, chlorophylls, tannins, and total phenolics were measured spectrophotometrically. The free radical-scavenging ability of seriguela fruit was measured by ABTS^·+ scavenging, DPPH^· scavenging, FRAP assay, and ORAC assay. HPLC analysis was used to estimate the carotenoids, organic acids, sugars, and phenolic compounds in fruit. The chlorophyll (38.43 μg/g DW) and condensed tannin (673.88 mg CA/g DW) contents were higher in unripe fruit pulp compared other fruit parts. The half-ripe fruit seeds contained higher amounts of total phenolics (9760.94 mg GAE/100 g DW), flavonoids (1760.22 mg QE/100 g DW), DPPH^· scavenging activity (361.34 mmol TE/g DW), and ORAC (63.48 mmol TE/g DW). The unripe fruit peel contains higher concentrations of β‑carotene (477.03 mg/g DW), citric acid (12.88 mg/100 g DW), and fumaric acid (11.81 mg/100 g DW), whereas glucose (17.34 mg/100 g DW) and fructose (508.37 mg/100 g) were higher in ripe fruit seeds. From the HPLC-DAD analysis, the epigallocatechin gallate concentration (80.15 to 89.74 mg/g) was found in all the fruit parts of Seriguela compared to other phenolic compounds. This study provides information on the phytochemical composition in order to use the fruit at its optimum stage of maturation.</p>