GENOTOXIC EVALUATION IN ZEBRAFISH OF QUINOIN, TYPE 1 RIBOSOME-INACTIVATING PROTEIN FROM QUINOA SEEDS

Nowadays, functional foods have greatly increased attention thanks to the numerous benefits for human health. Among them, quinoa contains all essential amino acids and minerals, for which is particularly suitable for consumption. However, quinoin (~30- kDa), a toxic enzyme classified as ribosome inactivating protein (RIP, EC: 3.2.2.22)1, recently found in quinoa seeds (Chenopodium quinoa Wild), exhibits in vitro cytotoxic action towards both normal fibroblasts and keratinocytes1 and several tumour cell lines.2 In this scenario, our study aims to evaluate quinoin genotoxicity on zebrafish specimens after intraperitoneal route administration of three different quinoin amounts (1- 5-10 μg) for 15 and 30 days of treatment by means: TUNEL reaction, RAPD-PCR and DCF assay. The results obtained showed that quinoin cause zebrafish genome damage, in terms of DNA frag- mentation, genomic instability and oxidative stress for all expo- sure times. The interesting data emerging from this study is a lower percentage of damage at longer quinoin treatment compared to shorter ones. This result could indicate the activation of detoxi- fying and/or repair mechanisms and/or a loss of protein activity by enzymatic digestion in the gastrointestinal tract since digestibility of quinoin by pepsin/trypsin in vitro digestion system has been ascertained1. Overall, quinoin can induce genotoxic damage to the zebrafish genome acting through ROS formation. Thus, our data suggest that the presence of quinoin in quinoa seeds could be very harmful if this pseudocereal is consumed with appropriate cook- ing, considering the melting temperature (Tm= 70°C) of quinoin1. Further studies are needed to investigate DNA damage response pathways to clarify the effective quinoin harmfulness.