Using the Layered Double Hydroxide-Lycopene Nanocomposite Formulation to Lessen Lycopene Toxicity in Danio rerio Embryos

Recently, we synthesized a layered double hydroxide-lycopene (LDH-lycopene) nanocomposite to enhance the dispersibility of lycopene in aqueous media, which is one of the drawbacks of carotenoids. As lycopene consumption is related to reducing the risk of diseases, LDH-lycopene has become an interesting ingredient to formulate nutraceuticals, food additives, and cosmetics. However, LDH-lycopene nanocomposite toxicity must be assessed before use by animals and humans. In this report, we demonstrated the structure of the LDH-lycopene nanocomposite by using a set of solid-state techniques such as X-ray diffraction (XRD), Raman, UV-vis, infrared (IR), and electron paramagnetic resonance (EPR) spectroscopies, besides dynamic light scattering (DLS) and transmission electron microscopy. The Danio rerio (zebrafish) embryo model was selected to conduct the acute toxicity assays (measuring of endpoints after embryo exposure by 96 h, from 4 to 100 h post-fertilization (hpf)), according to the OECD 236 protocol. Based on comparable experimental conditions, the LDH-lycopene nanocomposite barely reached 15% mortality at the highest concentration (1000 ppm); it was found to be less hazardous than its individual components, lycopene (LC50 of 304.9 ppm) and LDH (LC50 of 254.8 ppm). Although LDH-lycopene presented a lower toxicity for 1000 ppm, further analyses are required to find the safe concentration since a lower concentration than 30 ppm (33 times less) affected the dorsal curvature.