Liquiritigenin

The p53 Y220C is one of the most frequently observed structural mutants in various human cancers. The substitution of residue Tyr to Cys makes the p53 DNA binding domain susceptible to solvent entry into the hydrophobic core of the domain thereby destabilizing p53, which results in loss of its tumor suppressor activity. The mutation creates a structural crevice at the region between S3/S4 and S7/S8 loops in the DNA binding domain which can be targeted by small molecules. Studies have shown that the synthetic and natural compounds could bind to this crevice and restore the structure and function of the mutant p53Y220C to the wild type. In our previous study, we have shown Curcumin could rescue the function of mutant p53Y220C in pancreatic cancer cell line BxPC-3 harboring genomic mutation. In this study, we explored six flavonoids structurally similar to Curcumin such as Apigenin, Isoliquiritigenin, Liquiritigenin, Luteolin, Methylophiopogonanone A (MPA), and Methylophiopogonanone B (MPB) to test their potency to restore p53Y220C by molecular docking, molecular dynamics simulations and cytotoxicity assay. The secondary structure analysis after the MD simulations suggested that these compounds could stabilize the mutant p53 DNA binding domain to the wild type. In the cell-based cytotoxicity studies using p53Y220C harbouring BxPC-3 cell lines, the compounds MPA and MPB showed 75% cell death at 100 µM concentration. We proposed that the flavonoids MPA and MPB have the therapeutic potential to restore p53Y220C and could be used as a combinatorial therapy to reduce the dosage burden.Communicated by Ramaswamy H. Sarma.

Xiebai San (XBS), a classic Chinese prescription, has been used for the clinical treatment of pneumonia-related diseases for thousands of years. However, the anti-pneumonia pharmacodynamic material basis of XBS and its underlying mechanisms remain unclear.

This study aimed to comprehensively investigate and verify the anti-pneumonia pharmacodynamic material basis and mechanisms of XBS.

This study explored the anti-pneumonia activity and key pneumonia targets of XBS in lipopolysaccharide (LPS)-induced zebrafish and RAW264.7 cells in vivo and in vitro through transcriptomics, western blotting, and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The chemical fingerprint of XBS was established using high-performance liquid chromatography, and the similarities and areas of characteristic peaks of 15 batches of XBS were analyzed. Based on the spectrum-efficacy relationship, the potential anti-inflammatory components were screened according to their peak areas and efficacy using principal component analysis (PCA), bivariate correlation, and partial least squares regression analysis. Active components that bind to core targets were further screened based on surface plasmon resonance (SPR). The binding mode of proteins and components was simulated via molecular docking, which enabled the identification of the primary active components of XBS, thereby elucidating its anti-pneumonia properties. Finally, the anti-inflammatory activities of these components were verified in vitro.

XBS decreased neutrophil aggregation in zebrafish and nitric oxide (NO) secretion in RAW264.7 cells as well as suppressed the release of downstream inflammatory cytokines such as iNOS, TNF-α, IL-1β, IL-18, and CXCL10 related to TNF and JAK-STAT signaling pathways. The phosphorylation of IκBα, Akt, and Stat3 was alleviated after XBS in cells. The fingerprint similarities of 15 batches of XBS ranged from 0.381 to 0.994, with a large difference. A total of 15 characteristic peaks were identified, and the relative standard deviation of their peak areas ranged from 24.1% to 70.7%. The results of in vitro anti-inflammatory activities of 15 batches of XBS showed that all samples inhibited the expression levels of NO and nine inflammatory markers. The anti-inflammatory index of 15 batches of XBS was determined to be 0.69-0.96 based on transformation of the anti-inflammatory rate and composite index method via PCA. The spectrum-efficacy relationship model of 15 characteristic peak areas and the anti-inflammatory index showed that 7 main potential active components were related to the anti-inflammatory activity of XBS. Moreover, four components (mulberroside A, isoquercitrin, liquiritigenin, and glycyrrhizic acid) screened based on SPR had different affinities toward TNFR1, Akt1, and Stat3 proteins, and the binding modes were elucidated via molecular docking. Finally, in LPS-induced RAW264.7 cells, all four active components (at a concentration of 60 μM) significantly inhibited the expression levels of NO and inflammatory markers.

Based on the comprehensive strategy of spectrum-efficacy relationship and SPR, mulberroside A, isoquercitrin, liquiritigenin, and glycyrrhizic acid were identified as the primary pharmacodynamic active components involved in the anti-pneumonia activity of XBS and were found to intervene in TNF and JAK-STAT signaling pathways.