Detection of NAD(P)H by fluorescent probe to reveal the protective effects of natural antioxidants on acute liver injury

Acute liver injury as a serious inflammatory liver disease has a high morbidity and mortality rate. For drug treatment for acute liver injury, the focus was mainly from oxidative stress and rarely from a reductive perspective over the past decades. Herein, a novel quinoline-malononitrile-based fluorescent probe (QM-NA) designed for high efficiency sensitive detection of NAD(P)H, a critical marker related to reductive stress. QM-NA exhibited high selectivity for NADPH as well as a fast "turn-on" fluorescence response (4 min) with a Stokes shift of 77 nm, a detection limit of 18 nM, and favorable biocompatibility for cell-based experiments. With QM-NA in hand, the fluorescence imaging of endogenous and exogenous NADPH at the cellular level was achieved. More importantly, in vivo experiments demonstrated QM-NA was successfully used to visualize the fluctuations of NADPH and evaluate the efficacy of three antioxidants for the first time in acute liver injury mice. These above results afford a novel strategy for the treatment of acute liver injury and this probe is expected to be a promising molecular tool to evaluate the efficacy of hepatoprotective drugs. •A NIR fluorescent probe QM-NA based on the quinoline-malononitrile was developed for the detection of NAD(P)H.•The probe showed excellent selectivity, high sensitivity and rapid response towards NADPH.•The fluctuations of NADPH during acute liver injury with three antioxidants (apigenin, curcumin and resveratrol) treatment was visualized for the first time.