Screening and evaluation of antioxidants from lees by micro-injector systems combined with a fluorescent probe,N-borylbenzyloxycarbonyl-3,7-dihydroxyphenoxazine,in living Drosophila

Over the past few decades, the determination of antioxidant activity by chemical probe has been widely reported, but in vivo evaluation via model organisms of Drosophila melanogaster and rapid discovery system has not been studied adequately. In this study, we determined the antioxidant activity of lees and demonstrated the ability of compounds in lees to scavenge H₂O₂in vitro and in vivo by different chemical probes. Lees increased the ability of Drosophila against oxidative stress and antioxidant enzyme activity in vivo. Five ingredients of organic acids and flavones in lees extract that rapidly scavenged H₂O₂ were revealed by a post-column-derived HPLC-UV-FLD system based on 4-hydroxyphenylacetic acid (PHPAA) chemiluminescence. Additionally, another fluorescent probe, N-borylbenzyloxycarbonyl-3,7-dihydroxyphenoxazine (NBCD), was selected to evaluate the reactive oxygen species (ROS) scavenging capacity of lees in living Drosophila melanogaster using a microfluidic injection test coupled with microscopic imaging analysis, and similar effects were observed in flies when they were treated with tartaric acid and caffeic acid. The results demonstrated that the novel integrated system was suitable for screening and evaluating antioxidant ingredients from natural products.