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Introduction: Isatis tinctoria is a non-food Brassica plant that was extensively cultivated in Europe between the 12th and 17th centuries for the production of the blue indigo naturalis dye pigment. Presently, a project is underway to reintroduce the species to several European regions. However, the mere production of the pigment does not necessarily guarantee the economic viability of its cultivation. A considerable body of research has been dedicated to examining the antioxidant capacity of this plant. Extensive studies have demonstrated that extracts obtained from the cauline leaves exhibit notable antioxidant properties. Consequently, a direct incompatibility exists in the valorization of the plant between the production of pigment and the production of antioxidant compounds. Method: This study aims to circumvent this competitive dynamic; a zero-waste valorization of Isatis tinctoria can be posited. The antioxidant potential of both leaf residues after pigment extraction and roots was evaluated from a hydroponic culture of Isatis tinctoria. The antioxidant capacity of the obtained extracts was evaluated according to four colorimetric tests: ABTS, DPPH, FRAP, and CUPRAC. Results: The results of the study indicate that the re-use of the cauline leaves of Isatis tinctoria is possible, in particular through its DPPH (544 μmol TE/100g DW) and CUPRAC (807 μmol TE/100g DW) activities. Nevertheless, the drying process following pigment extraction must be enhanced to ensure the reproducibility of results. It has been observed that the roots of Isatis tinctoria exhibit a degree of interest, albeit to a more moderate extent, in terms of metal reduction activities (FRAP: 120 μmol TE/100g FW; CUPRAC: 250 μmol TE/100g FW). Discussion: However, it is imperative to optimize both the drying step and the extraction methodology. Furthermore, the components constituting both extracts must be characterized. Conclusion: The subsequent study demonstrated that Isatis tinctoria leaves, a byproduct of indigo extraction, can be valorized through a biocascade approach for the production of an antioxidant extract. Furthermore, the study suggests that plant zero-waste valorization can be achieved through the extraction of antioxidants from Isatis tinctoria roots.