Crocetin is a main bioactive component with a carotenoid skeleton in Gardenia jasminoides, a typical traditional Chinese medicine with a long history in Southeast Asia. Crocetin is being commonly consumed as spices, dyes, and food colorants. Recent pharmacological studies had implied that crocetin may possess potent anti-inflammatory properties; however, the underlying molecular mechanism is not fully elucidated. In the present study, the regulatory effect of crocetin on redox balance was systematically investigated in lipopolysaccharide- (LPS-) stimulated RAW264.7 cells. The results showed that crocetin dose-dependently inhibited LPS-induced nitric oxide production and inducible nitric oxide synthase (iNOS) expression in RAW264.7 cells. Molecular data revealed that crocetin exerted its anti-inflammatory property by inhibiting the MEK1/JNK/NF-κB/iNOS pathway and activating the Nrf2/HO-1 pathway. The shRNA-knockdown (KD) of MEK1 and ERK1 confirmed that the activation of MEK1 and inhibition of JNK mediated the anti-inflammatory effect of crocetin. Moreover, the pull-down assay and computational molecule docking showed that crocetin could directly bind to MEK1 and JNK1/2. It is noticed that both KD and knockout (KO) of HO-1 gene blocked this action. More detailed data have shown that HO-1-KO blocked the inhibition of p-IκB-α by crocetin. These data indicated that crocetin exerted its anti-inflammatory property via modulating the crosstalk between the MEK1/JNK/NF-κB/iNOS pathway and the Nrf2/HO-1 pathway, highlighting HO-1 as a major player. Therefore, the present study reveals that crocetin can act as a potential candidate for redox-balancing modulation in charge of its anti-inflammatory and chemopreventive effect, which strengthens its potency in the subsequent clinic application in the near future.

中文翻译：

---

藏红花素可能通过调节 MEK1/JNK/NF-κB/iNOS 通路和 Nrf2/HO-1 通路之间的串扰在 LPS 诱导的 RAW264.7 细胞中发挥其抗炎特性

藏红花素是栀子中具有类胡萝卜素骨架的主要生物活性成分，是东南亚历史悠久的典型中药。藏红花素通常被用作香料、染料和食品着色剂。最近的药理学研究表明，藏红花素可能具有有效的抗炎特性。然而，潜在的分子机制尚未完全阐明。在本研究中，在脂多糖（LPS-）刺激的 RAW264.7 细胞中系统地研究了藏红花素对氧化还原平衡的调节作用。结果表明，藏红花酸剂量依赖性地抑制 LPS 诱导的 RAW264.7 细胞中一氧化氮的产生和诱导型一氧化氮合酶 (iNOS) 的表达。分子数据显示，藏红花素通过抑制 MEK1/JNK/NF- κ发挥抗炎作用B/iNOS 通路和激活 Nrf2/HO-1 通路。MEK1和ERK1的shRNA敲低（KD）证实MEK1的激活和JNK的抑制介导了藏红花素的抗炎作用。此外，下拉分析和计算分子对接表明藏红花素可以直接与MEK1和JNK1/2结合。值得注意的是，HO-1基因的 KD 和敲除 (KO) 都阻断了这一作用。更详细的数据表明，HO-1 -KO 阻断了藏红花酸对 pI κ B -α的抑制作用。这些数据表明，藏红花素通过调节 MEK1/JNK/NF- κ之间的串扰发挥其抗炎特性B/iNOS 通路和 Nrf2/HO-1 通路，突出 HO-1 作为主要参与者。因此，本研究表明藏红花素可以作为氧化还原平衡调节的潜在候选者，负责其抗炎和化学预防作用，这将在不久的将来加强其在后续临床应用中的效力。