Diterpenoid glucosides with anti-inflammatory activity from Sigesbeckia glabrescens.

Six previously undescribed diterpenoid glucosides, along with four known compounds, were isolated from the aerial parts of Sigesbeckia glabrescens. The structures and absolute configurations of undescribed compounds were elucidated using extensive spectroscopic techniques, ECD calculations and chemical methods. Compounds 1 and 8 exhibited anti-inflammatory activity against LPS-induced NO production in RAW 264.7 macrophages, with compound 8 demonstrating significant inhibitory activity compared to positive control minocycline, boasting an IC50 value at 14.20 µM.

Inhibitory Potential of Quercetin Derivatives Isolated from the Aerial Parts of Siegesbeckia pubescens Makino against Bacterial Neuraminidase.

This study aimed to isolate bacterial neuraminidase (BNA) inhibitory O-methylated quercetin derivatives from the aerial parts of S. pubescens. All the isolated compounds were identified as O-methylated quercetin (1-4), which were exhibited to be noncompetitive inhibitors against BNA, with IC50 ranging from 14.0 to 84.1 µM. The responsible compounds (1-4) showed a significant correlation between BNA inhibitory effects and the number of O-methyl groups on quercetin; mono (1, IC50 = 14.0 µM) > di (2 and 3, IC50 = 24.3 and 25.8 µM) > tri (4, IC50 = 84.1 µM). In addition, the binding affinities between BNA and inhibitors (1-4) were also examined by fluorescence quenching effect with the related constants (KSV, KA, and n). The most active inhibitor 1 possessed a KSV with 0.0252 × 105 L mol-1. Furthermore, the relative distribution of BNA inhibitory O-methylated quercetins (1-4) in S. pubescens extract was evaluated using LC-Q-TOF/MS analysis.

Therapeutic effects of Siegesbeckia orientalis L. and its active compound luteolin in rheumatoid arthritis: network pharmacology, molecular docking and experimental validation.

ETHNOPHARMACOLOGICAL RELEVANCE: Rheumatoid arthritis (RA) is a common difficult disease with a high disability rate. Siegesbeckia orientalis L. (SO), a Chinese medicinal herb that is commonly used for treating RA in clinical practice. While, the anti-RA effect and the mechanisms of action of SO, as well as its active compound(s) have not been elucidated clearly. AIM OF THE STUDY: We aim to explore the molecular mechanism of SO against RA by using network pharmacology analysis, as well as the in vitro and in vivo experimental validations, and to explore the potential bioactive compound(s) in SO. METHODS: Network pharmacology is an advanced technology that provides us an efficient way to study the therapeutic actions of herbs with the underlying mechanisms of action delineated. Here, we used this approach to explore the anti-RA effects of SO, and then the molecular biological approaches were used to verify the prediction. We first established a drug-ingredient-target-disease network and a protein-protein interaction (PPI) network of SO-related RA targets, followed by the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Further, we used lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and vascular endothelial growth factor-A (VEGFA)-induced human umbilical vein endothelial cell (HUVEC) models, as well as adjuvant-induced arthritis (AIA) rat model to validate the anti-RA effects of SO. The chemical profile of SO was also determined by using the UHPLC-TOF-MS/MS analysis. RESULTS: Network pharmacology analysis highlighted inflammatory- and angiogenesis-related signaling pathways as promising pathways that mediate the anti-RA effects of SO. Further, in both in vivo and in vitro models, we found that the anti-RA effect of SO is at least partially due to the inhibition of toll like receptor 4 (TLR4) signaling. Molecular docking analysis revealed that luteolin, an active compound in SO, shows the highest degree of connections in compound-target network; moreover, it has a direct binding to the TLR4/MD-2 complex, which is confirmed in cell models. Besides, more than forty compounds including luteolin, darutoside and kaempferol corresponding to their individual peaks were identified tentatively via matching with the empirical molecular formulae and their mass fragments. CONCLUSION: We found that SO and its active compound luteolin exhibit anti-RA activities and potently inhibit TLR4 signaling both in vitro and in vivo. These findings not only indicate the advantage of network pharmacology in the discovery of herb-based therapeutics for treating diseases, but also suggest that SO and its active compound(s) could be developed as potential anti-RA therapeutic drugs.