In recent years, natural deep eutectic solvents (NADES) have been widely investigated for the extraction of food and medicinal plants as well as seaweeds. However, the ability of NADES for trace elements co-extraction from natural sources is not well investigated. The aim of this study was to investigate the ability of common NADES for trace elements co-extraction from Fucus vesiculosus. All of the tested NADES did not recover As and Co (concentration <LOQ). Moreover, all of the tested NADES provided a low recovery (<9%) of Ba, Ca, Fe, Mg, Mn, Sr, and Zn. The method of extraction had not shown a statistically significant effect on the co-extraction of all elements (excluding Ba and Ca). In contrast, the water content in NADES was significantly affected on the recovery of Ba, Ca, Mg, Mn, Sr, and Zn. The recovery of Al and Cr was relatively high and considerably varied (from 1.5 to 59.9%). NADES comprising lactic acid:glucose:H2O (5:3:1) provided the lowest contents of all elements, and the highest extracted amounts were obtained employing water contents of 60−80%. The calculated daily intake of all the elements contained in NADES extracts were less than the daily dose risk estimators. The hazard quotients, hazard indexes, and carcinogenic risk calculated for all trace elements and their combination were considerably less than 1. This evidences no health risk, and carcinogenic risk after topical application of all studied NADES. For the first time, the results of the current study demonstrated that NADES extracts of F. vesiculosus contain a lower amount of trace metals and are safer than the extracts obtained with water and 70% acetone. This indicates a significant advantage for NADES compared with the other solvents.
Keywords: Fucus vesiculosus; NADES; extraction; hazard quotient; health risk; natural deep eutectic solvents; trace elements; trace metals.