Biflavonoids from Juniperus oblonga inhibit organic anion transporter 3

Bilobetin attenuates Staphylococcus aureus virulence by targeting Von Willebrand factor-binding protein and staphylocoagulase

Staphylococcus aureus (S. aureus) induces a variety of infectious diseases in humans and animals and is responsible for hospital- and community-acquired infections. The aim of this study was to investigate how bilobetin, a natural compound, attenuates S. aureus virulence by inhibiting two key virulence factors, von Willebrand factor-binding protein (vWbp) and staphylocoagulase (Coa). The results showed that bilobetin inhibited Coa- or vWbp-induced coagulation without affecting S. aureus proliferation. The Western blotting and fluorescence quenching assays indicated that bilobetin did not affect the expression of vWbp and Coa but directly bound to the proteins with KA values of 1.66 × 104 L/mol and 1.04 × 104 L/mol, respectively. To gain further insight into the mechanism of interaction of bilobetin with these virulence factors, we performed molecular docking and point mutation assays, which indicated that the TYR-6 and TYR-18 residues on vWbp and the ALA-190 and ASP-189 residues on Coa were essential for the binding of bilobetin. In addition, the in vivo studies showed that bilobetin ameliorated lung tissue damage and inflammation caused by S. aureus, thereby improving the survival of mice. Furthermore, the use of bilobetin as an adjuvant in combination with vancomycin was more effective in the treatment of a mouse model of pneumonia. Taken together, bilobetin had a dual inhibitory effect on vWbp and Coa by reducing the virulence of S. aureus, suggesting that it is a viable lead compound against S. aureus infections.

Transporter-mediated Natural Product-Drug Interactions

The increasing use of natural products in clinical practice has raised great concerns about the potential natural product-drug interactions (NDIs). Drug transporters mediate the transmembrane passage of a broad range of drugs, and thus are important determinants for drug pharmacokinetics and pharmacodynamics. Generally, transporters can be divided into ATP binding cassette (ABC) family and solute carrier (SLC) family. Numerous natural products have been identified as inhibitors, substrates, inducers, and/or activators of drug transporters. This review article aims to provide a comprehensive summary of the recent progress on the research of NDIs, focusing on the main drug transporters, such as P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), organic anion transporter 1 and 3 (OAT1/OAT3), organic anion-transporting polypeptide 1B1 and 1B3 (OATP1B1/OATP1B3), organic cation transporter 2 (OCT2), multidrug and toxin extrusion protein 1 and 2-K (MATE1/MATE2-K). Additionally, the challenges and strategies of studying NDIs are also discussed.

Insights Into Amentoflavone: A Natural Multifunctional Biflavonoid

Amentoflavone is an active phenolic compound isolated from Selaginella tamariscina over 40 years. Amentoflavone has been extensively recorded as a molecule which displays multifunctional biological activities. Especially, amentoflavone involves in anti-cancer activity by mediating various signaling pathways such as extracellular signal-regulated kinase (ERK), nuclear factor kappa-B (NF-κB) and phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), and emerges anti-SARS-CoV-2 effect via binding towards the main protease (Mpro/3CLpro), spike protein receptor binding domain (RBD) and RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2. Therefore, amentoflavone is considered to be a promising therapeutic agent for clinical research. Considering the multifunction of amentoflavone, the current review comprehensively discuss the chemistry, the progress in its diverse biological activities, including anti-inflammatory, anti-oxidation, anti-microorganism, metabolism regulation, neuroprotection, radioprotection, musculoskeletal protection and antidepressant, specially the fascinating role against various types of cancers. In addition, the bioavailability and drug delivery of amentoflavone, the molecular mechanisms underlying the activities of amentoflavone, the molecular docking simulation of amentoflavone through in silico approach and anti-SARS-CoV-2 effect of amentoflavone are discussed.

Unusual Flavones from Primula macrocalyx as Inhibitors of OAT1 and OAT3 and as Antifungal Agents against Candida rugosa

A bioactivity guided program exploring the interaction of phytochemicals in the entire plant Primula macrocalyx with the organic anion transporters (OAT1 and OAT3) and microorganisms led to the elucidation of ten known flavones (1–4, 6–10, 12) and two previously undescribed flavones (5, 11). The structures of the compounds were determined by extensive analysis of spectroscopic data, as well as by comparison with data from previous reports. Two known flavones (9, 12) are reported for the first time from the family Primulaceae. All compounds were evaluated for inhibition of OAT1 and OAT3. Six flavones (2, 3, 6–8, 12) showed potent inhibitory activity on OAT1, while seven flavones (2, 3, 6–9, 12) showed marked inhibitory activity on OAT3, with IC₅₀ ≤ 10.0 µM. Antimicrobial activities of crude fractions against sixteen microorganisms were tested to give a target yeast strain Candida rugosa for further evaluation of MICs on the isolates. Three flavones (7, 8, 12) showed marked antifungal activity with MIC < 2.0 µM. To our knowledge, this study is the first to evaluate these flavones as inhibitors of the OAT1 and OAT3, and as antifungal agents.