Neglected and underutilized species (NUS) has been appointed as central key to overcome the challenges relate to food security and ensure a diversified and healthy diet. NUS can be offer as alternative sources of health promoting compounds, especially for low-income people that are greatly affected by micronutrient deficiencies. In this context, Brazil has great potential to prevail such challenges due its wealth of agricultural biodiversity, which includes wild and unexplored species, such as purslane (Portulaca oleracea L.), culantro (Eryngium foetidum L.), barbados gooseberry (Pereskia aculeata Mill.), taioba (Xanthosoma taioba E.G. Gonç.) and false roselle (Hibiscus acetosella W.). In light of this, the presented study was conducted to optimize the extraction of total phenolic content (TPC) for the five aforementioned plants. For this purpose, a PB12 and a CCRD were performed, in order to evaluate five variables, named extraction steps, time, temperature, solid-to-liquid ratio and methanol concentration. Moreover, antioxidant capacity by DPPH, ABTS and FRAP methods, as well as, ascorbic acid (AA) and dehydroascorbic acid (DHA) quantification were accessed. Optimized conditions results in TPC of 60.53 mg GAE/g DWfor barbados gooseberry, 11.84 mg GAE/g DW for culantro, 70.82 mg GAE/g DW for false roselle, 30.87 mg GAE/g DW for purslane and 25.33 mg GAE/g DW for taioba. The samples presented high antioxidant capacities, ranging from 44.02 μmol T.E./g DW to 405.04 μmol T.E./g DW for ABTS, 34.69 μmol T.E./g DW to 316.56 μmol T.E./g DW for DPPH and 56.37 μmol T.E./g DW to 108.12 μmol TE/gDW for FRAP. The high antioxidant capacities might be related to the total phenolic content, as well as, to the considerable concentration of AA (ranging from 2.98 mg vit.C/100g DW to 50.61 mg vit.C/100g DW) and DHA (ranging from 1.83 mg vit.C/100g DW to 84.77 mg vit.C/100g DW) found in the plants.