Licochalcone B

Glycyrrhiza uralensis Fisch. (licorice) has been widely used in traditional medicine for the treatment of infections, gastritis, cancer, and pain. While its anti-cancer properties, particularly against gastric, lung, colon, and liver cancers, have recently attracted increasing interest, the underlying mechanisms, especially those related to its antioxidative and anti-angiogenic activities remain largely unexplored. This study aimed to isolate and characterize bioactive compounds from the methanol (MeOH) extract of G. uralensis and evaluate their effects on hypoxia-inducible factor-1 alpha (HIF-1α) and related pathways. Phytochemical investigation of the MeOH extract of G. uralensis roots aided by liquid chromatography-mass spectrometry led to the isolation of 6 compounds (1-6), which were structurally characterized as licochalcone A (1), licochalcone B (2), liquiritigenin (3), liquiritin (4), isoliquiritin (5), and 3,3',4,4'-tetrahydroxy-2-methoxychalcone (TMC, 6) by spectral analysis, mainly ESI-MS, UV, and NMR data. Among them, TMC showed the strongest inhibitory effects on both HIF-1α and Nrf2 signaling. In HCT-116 human colorectal cancer cells, TMC significantly reduced hypoxia-induced HIF-1α protein accumulation without altering its mRNA level, and this effect was reversed by MG132, suggesting that proteasome-dependent mechanisms contribute to the reduction of HIF-1α protein levels. TMC also decreased VEGF expression. In addition, TMC suppressed Nrf2 and HO-1 expression and reduced Nrf2 mRNA stability under hypoxic conditions. Despite inhibition of the Nrf2/HO-1 axis, TMC reduced intracellular ROS levels and exhibited mild radical-scavenging activity in the DPPH assay, suggesting that TMC may contribute to redox balance under hypoxic conditions. In human umbilical vein endothelial cells, TMC inhibited VEGF-induced migration and tube formation and attenuated VEGFR2 phosphorylation. In zebrafish, TMC reduced HIF-1α protein levels without gross developmental or cardiac toxicity. Collectively, these findings indicate that TMC exerts anti-angiogenic activity by targeting the HIF-1α/VEGF pathway, modulating VEGFR2 activation, and suppressing Nrf2/HO-1 signaling through reduced Nrf2 mRNA stability, highlighting its potential as a therapeutic candidate for hypoxia-associated tumor angiogenesis.

Pulmonary hypertension (PH) is characterized by pulmonary vascular remodeling, and Furin, a proprotein convertase critical for TGF-β1 activation, has shown promise as a novel therapeutic target for PH. However, its specific role in PH pathogenesis and potential inhibitors have remained unexplored.

This study aimed to investigate the role of Furin in PH-associated vascular remodeling and evaluate the therapeutic potential of the newly discovered Furin inhibitor, Licochalcone B (LicoB), in PH.

We assessed Furin expression levels in multiple PH animal models and evaluated its cellular localization using single-cell transcriptomics. Then the functional role of Furin was validated through overexpression and knockdown studies in vitro. The protective effect of Furin inhibitor, LicoB, was validated in pulmonary artery vascular cells, and finally its therapeutic effects and potential mechanisms were evaluated in PH animal models.

Elevated Furin expression was consistently observed across diverse PH animal models. Furin overexpression promoted cell viability and migration, while its knockdown mitigated pathological features. The Furin inhibitor, LicoB, effectively suppressed aberrant pulmonary artery cell proliferation and migration, and restored mitochondrial membrane potential in vitro. Critically, in both murine and rat PH models, LicoB administration significantly ameliorated symptoms, exerted robust cardiopulmonary protection, and attenuated pulmonary vascular remodeling. Mechanistically, LicoB acted by inhibiting the Furin/TGF-β1 signaling axis.

Our findings establish Furin as a key driver of PH development and demonstrate that LicoB suppresses vascular remodeling via the Furin/TGF-β1 pathway, positioning LicoB as a highly promising novel therapeutic candidate for PH by targeting Furin.