Natural Colorants From Amazonian Plants: Bioactive Potential and Sustainable Extraction Techniques-A Review

This review synthesized and compared extraction methodologies for anthocyanins, carotenoids, betalains, and chlorophylls from Amazonian species, highlighting extraction yield, compound stability, bioactivity preservation, and industrial feasibility of conventional and green approaches. A systematized search was conducted in Google Scholar, ScienceDirect, PubMed, SciELO, ACS Publications, and Scopus, covering publications from 2010 to 2025. Eligible studies included original articles, systematic reviews, and laboratory assays reporting extraction techniques with analytical identification confirmed by high-performance liquid chromatography (HPLC) or spectrophotometry and quantitative yield data. In total, 36 records of Amazonian species were analyzed: anthocyanins (n = 12), carotenoids (n = 9), betalains (n = 6), and chlorophylls (n = 10), in addition to 18 comparative studies involving other plant matrices. açaí (Euterpe oleracea), bacaba (Oenocarpus bacaba), and camu-camu (Myrciaria dubia) were the main sources of anthocyanins, whereas buriti (Mauritia flexuosa) and tucumã (Astrocaryum vulgare) accounted for most carotenoid reports. Betalains were primarily described in pitaya and facheiro, and chlorophylls in tree leaves. Deep eutectic solvents (DES), natural deep eutectic solvents (NADES), and supercritical carbon dioxide (CO₂), combined with ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and pulsed electric fields (PEF), showed superior performance compared with conventional methods. DES containing choline chloride achieved 41.3 mg/100 g of carotenoids versus 11.5 mg/100 g with ethanol, being up to 3.5 times more efficient. The PEF-ethanol combination recovered more than 80% of total carotenoids. Green solvents associated with emerging technologies represent technically viable and environmentally superior routes, while native betalains and chlorophylls remain underexplored, representing a priority research gap.