Arylacetamides exhibit antiproliferative effects on non-transformed mammalian and vegetal cells and toxicity on crustaceans and fish embryos

Non-clinical steps for development, validation and biosafety of new medicines and products comprises studies on cells, proteins, and animals. Herein, we evaluated the toxic activity of antitumoral 2-chloro-<i>N</i>-arylacetamides on eukaryotic dividing cells and animal replacement models. Firstly, the cytotoxicity of chloro (compound <b>2</b>), bromo (compound <b>3</b>) and nitro (compound <b>4</b>) acetamides was analyzed by fluorescent assays in fibroblasts. Next, toxicity was evaluated on <i>Allium cepa</i> meristematic cells and 48h-living <i>Artemia salina</i> larvae. Finally, embryos of <i>Danio rerio</i> (zebrafish) were exposed to the compound <b>2</b> (0.14 - 7.2 μg/mL) for 120 h exposure. All arylacetamides were cytotoxic on murine and human fibroblasts, with IC₅₀ values ranging from 1.2 μg/mL (5.6 µM = compound <b>4</b> on L-929) to 4.9 μg/mL (24 µM = compound <b>2</b> on MRC-5 cells), respectively, and inhibited root growth from 10 to 100 µg/mL, corroborated by mitotic index reduction and cell cycle arrest in interphase (<i>p</i> < 0.05) without clastogenic injuries. Compound <b>2</b> showed time- and concentration-dependent killing effects on zebrafish embryos. Its 24 h-acute toxicity at higher concentrations (1.93 and 7.2 μg/mL with 90% and 100% death) corroborated toxicity on aquatic <i>A. salina</i> organisms. After 96 h exposure at 0.52 μg/mL (2.55 µM), almost 100% of the embryos showed more than one lethal/sublethal morphological abnormality (<i>p</i> < 0.05). Then, all arylacetamides showed unspecific toxic effects, mainly the halogenated electrophile chloroacetamide. They present strong antimitotic action on vertebrate and vegetal cells, although such antiproliferative activity does not seem to be directly related to chromosomal damage inductions.