Myrciaria cauliflora (Mart.) O. Berg, known as jabuticaba, is a native species to Brazil, more specifically to Atlantic Rainforest biome. Its fruits are small berries with a diameter of 2.0 – 3.5 cm that contain between one and four seeds, with a sweet gelatinous pulp and thick dark purple epicarp when mature, which is not commonly consumed. Due to the properties of its pulp, the consumption and production of jellies and liqueurs from jabuticaba has increased. However, the epicarp that corresponds to about 50% of the fruit is not used, being converted into a bioresidue [1]. The intense colour of this part of the fruit is due to the pigments, namely anthocyanins, present in its composition. In addition to attractive staining, these molecules have been associated with bioactive properties, such as antioxidant activity, which makes their recovery interesting for application in various industrial segments, for instance, food and pharmaceutical [2,3]. With the objective of valorising this bioresidue, the present work aimed the determination of the main anthocyanins present in jabuticaba epicarp (by HPLC-DAD-ESI/MS) and the evaluation of the bioactivity of its ethanolic extract (through in vitro assessment of cytotoxic, antimicrobial, and antioxidant activities). Thus, cytotoxicity was evaluated in four tumour cell lines (NCI-H460 - lung carcinoma, MCF-7 - breast carcinoma, HepG2 - hepatocellular carcinoma, and HeLa - cervical carcinoma) and in a primary culture of non-tumour liver cells (PLP2), by the Sulforodamine B (SRB) assay. The antimicrobial activity was evaluated on five Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Morganella morgani, Proteus mirabilis, and Pseudomonas aeruginosa) and three Gram-positive bacteria (Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis). Lastly, the antioxidant activity was tested through the oxidative haemolysis inhibition assay (OxHLIA). The bioresidue of jabuticaba fruits presented two anthocyanins, identified as cyanidin 3-O-glucoside and delphinidin 3-O-glucoside, being the first one the most abundant. Regarding bioactivity, the ethanolic extract revealed antiproliferative activity in all tumour cell lines evaluated (GI50 < 300 μg/mL), except for NCI-H460, and did not show toxicity for PLP2 at the maximal tested concentration (400 μg/mL). It also exhibited bacteriostatic properties in all the analysed bacterial strains (ranging from 20 to 10 mg/mL). Regarding haemolysis inhibition, the extract was able to protect 50% of the erythrocyte population for 120 minutes in a lower concentration than the positive control (Trolox). The results obtained in this study allow to conclude that jabuticaba epicarp is a rich source of anthocyanins and also exhibits strong bioactivity, which makes it suitable for use as colorant.