Processed Scutellaria baicalensis Georgi Extract Alleviates LPS-Induced Inflammatory and Oxidative Stress through a Crosstalk between NF-κB and KEAP1/NRF2 Signaling in Macrophage Cells

Abstract

Prolonged inflammation results in chronic diseases that can be associated with a range of factors. Medicinal plants and herbs provide synergistic benefits based on the interaction of multiple phytochemicals. The dried root of Scutellaria baicalensis Georgi and its compounds possess anti-inflammatory, anti-oxidative, and anticancer effects. Processing is a traditional method to achieve clinical benefits by improving therapeutic efficacy and lowering toxicity. In this study, we investigated the anti-inflammatory and anti-oxidant effect of processed Scutellaria baicalensis Georgi extract (PSGE) against lipopolysaccharide (LPS) stimulated RAW 264.7 cells. Data using Griess assay and ELISA showed that PSGE decreased nitric oxide and prostaglandin E2 (PGE2) levels against LPS. PSGE treatment up-regulated 15-hydroxyprostaglandin dehydrogenase (PGDH), while cyclooxygenase (COX)-2 and microsomal prostaglandin E synthase (mPGES)-1 expression did not change. Interestingly, PGE2 inhibition was regulated by prostaglandin catabolic enzyme 15-PGDH rather than COX-2/mPGES-1, enzymes essential for PGE2 synthesis. Additionally, PSGE-suppressed LPS-induced IL-6 and TNF-α production through NF-κB signaling. NF-κB release from an inactive complex was inhibited by HO-1 which blocked IκBα phosphorylation. The ROS levels lowered by PSGE were measured with the H2DCFDA probe. PSGE activated NRF2 signaling and increased antioxidant Hmox1, Nqo1, and Txn1 gene expression, while reducing KEAP1 expression. In addition, pharmacological inhibition of HO-1 confirmed that the antioxidant enzyme induction by PSGE was responsible for ROS reduction. In conclusion, PSGE demonstrated anti-inflammatory and anti-oxidant effects due to NRF2/HO-1-mediated NF-κB and ROS inhibition.

Electrochemical CO2reduction to ethanol: from mechanistic understanding to catalyst design

“…Adding other transition-metal dopants to Cu catalyst can also result in higher selectivity towards alcohol products from the CO electroreduction. 25 This strategy is based on the diverging mechanistic pathway following the formation of 𝐻𝑂𝐶𝐶𝐻 * intermediate, which involves two possibilities:…”

“…After screening potential dopants using DFT calculations, Pd dopant was found to be optimal since the addition of Pd dopant to Cu surface decreases the free energy of hydrogenation (or increase the free energy of dehydroxylation). 25 This study is one example of utilizing knowledge of mechanistic pathways to identify a key mechanism, and using DFT to realize how to influence it toward the desired direction. As we established that the specific CO reduction mechanisms are circumstantial and often competitive, this approach can be applied to other reaction conditions, catalyst surfaces, etc.…”