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BACKGROUND AND PURPOSESauchinone, an antioxidant lignan, protects hepatocytes from iron-induced toxicity. This study investigated the protective effects of sauchinone against acetaminophen (APAP)-induced toxicity in the liver and the role of nuclear factor erythroid-2-related factor-2 (Nrf2) in this effect. EXPERIMENTAL APPROACHBlood biochemistry and histopathology were assessed in mice treated with APAP or APAP + sauchinone. The levels of mRNA and protein were measured using real-time PCR assays and immunoblottings. KEY RESULTSSauchinone ameliorated liver injury caused by a high dose of APAP. This effect was prevented by a deficiency of Nrf2. Sauchinone treatment induced modifier subunit of glutamate-cysteine ligase, NAD(P)H:quinone oxidoreductase-1 (NQO1) and heat shock protein 32 in the liver, which was abolished by Nrf2 deficiency. In a hepatocyte model, sauchinone activated Nrf2, as evidenced by the increased nuclear accumulation of Nrf2, the induction of NQO1-antioxidant response element reporter gene, and glutamate-cysteine ligase and NQO1 protein induction, which contributed to the restoration of hepatic glutathione content. Consistently, treatment of sauchinone enhanced Nrf2 phosphorylation with a reciprocal decrease in its interaction with Kelch-like ECH-associated protein-1. Intriguingly, sauchinone activated protein kinase C-d (PKCd), which led to Nrf2 phosphorylation. In addition, it increased the inhibitory phosphorylation of glycogen synthase kinase-3b (GSK3b), derepressing Nrf2 activity, which was supported by the reversal of sauchinone's activation of Nrf2 by an activated mutant of GSK3b. Moreover, phosphorylation of GSK3b by sauchinone depended on PKCd activation. CONCLUSION AND IMPLICATIONSOur results demonstrate that sauchinone protects the liver from APAP-induced toxicity by activating Nrf2, and this effect is mediated by PKCd activation, which induces inhibitory phosphorylation of GSK3b. AbbreviationsALT, alanine aminotransferase; AMPK, AMP-activated protein kinase; APAP, acetaminophen; ARE, antioxidant response element; AST, aspartate aminotransferase; GCL, glutamate-cysteine ligase; GCLM, modifier subunit of glutamate-cysteine ligase; GSH, glutathione; GSK3b, glycogen synthase kinase 3b; HSP32, heat shock protein 32; Keap1, Kelch-like ECH-associated protein-1; KO, knockout; LDH, lactate dehydrogenase; NAPQI, N-acetyl-p-benzoquinoneimine; NQO1, NAD(P)H:quinone oxidoreductase-1; Nrf2, nuclear factor erythroid-2-related factor-2; PKCd, protein kinase C d; PMA, phorbol 12-myristate 13-acetate; ROS, reactive oxygen species; WT, wild-type

The effect of salt treatment on Brassica carinata (BC) microgreens grown under different light wavelengths on glucosinolates (GLs) and phenolic compounds were evaluated. Quantifiable GLs were identified using ultra-high performance-quadrupole time of flight mass spectrometry. Extracts’ ability to activate antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) was evaluated on human colorectal carcinoma cells (HCT116). Furthermore, BC compounds’ ability to activate expression of nuclear transcription factor-erythroid 2 related factor (Nrf2) and heme-oxygenase-1 (HO-1) proteins was examined using specific antibodies on HCT116 cells. Sinigrin (SIN) was the abundant GLs of the six compounds identified and its content together with total aliphatic GLs increased in saline conditions. Fluorescent (FL) and blue plus red (B1R1) lights were identified as stable cultivation conditions for microgreens, promoting biomass and glucobrassicin contents, whereas other identified individual and total indole GLs behaved differently in saline and non-saline environments. Blue light-emitting diodes and FL light in saline treatments mostly enhanced SIN, phenolics and antioxidant activities. The increased SOD and CAT activities render the BC microgreens suitable for lowering oxidative stress. Additionally, activation of Nrf2, and HO-1 protein expression by the GLs rich extracts, demonstrate their potential to treat and prevent oxidative stress and inflammatory disorders. Therefore, effective salt treatments and light exposure to BC microgreens present an opportunity for targeted regulation of growth and accumulation of bioactive metabolites.