Development and validation of a sensitive UHPLC-MS/MS method for quantitative analysis of farrerol in rat plasma: Application to pharmacokinetic and bioavailability studies

The fate of flavonoids after oral administration: a comprehensive overview of its bioavailability

Despite advancements in synthetic chemistry, nature remains the primary source of drug discovery, and this never-ending task of finding novel and active drug molecules will continue. Flavonoids have been shown to possess highly significant therapeutic activities such as anti-inflammatory, anti-oxidant, anti-viral, anti-diabetic, anti-cancer, anti-aging, neuroprotective, and cardioprotective, etc., However, it has been found that orally administered flavonoids have a critical absorption disorder and, therefore, have low bioavailability and show fluctuating pharmacokinetic and pharmacodynamic responses. A detailed investigation is required to assess and analyze the variation in the bioavailability of flavonoids due to interactions with the intestinal barrier. This review will emphasize on the bioavailability and the pharmacological applications of flavonoids, key factors affecting their bioavailability, and strategies for enhancing bioavailability, which may lead to deeper understanding of the extent of flavonoids as a treatment and/or prevention for different diseases in clinics.

Farrerol ameliorate adjuvant-induced ankle injury via alteration of PPAR-γ signal pathway

This study evaluated the anti-inflammatory activity against lipopolysaccharide (LPS)-mediated mouse macrophages (in vitro) and assessed the protective effect of farrerol on arthritis caused by complete freund adjuvant (CFA) in rats. For the evaluation of the pharmacological effect of farrerol on the activity of nitric oxide (NO) and cyclooxygenase, pro-inflammatory cytokines including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β, RAW 264.7 cells were used. A 0.1 ml CFA was injected subcutaneously for the induction of arthritis. The paw volume, body weight and arthritic score were estimated at regular intervals. Pro-inflammatory cytokines, inflammatory mediators, and antioxidant parameters were also estimated. Farrerol suppressed NO production and COX-catalyzed prostaglandin (PGE₂ ) in RAW 264.7. Farrerol also downregulated the p-p65, p-IκBα expression and upregulated the PPAR-γ expression in RAW 264.7 cells. Treatment of farrerol increased body weight substantially, and reduced paw edema and arthritic score. Farrerol treatment also significantly improved the level of hemoglobin (Hb), count of red blood cells (RBC), and decreased the rate of erythrocyte sedimentation (ESR), white blood cell (WBC) parameters, while the generation of pro-inflammatory cytokines inhibited. Together, farrerol also suppressed the pro-inflammatory cytokines TNF-α, IL-6, and IL-1β. Obtained results directed that the farrerol exerted its therapeutic effect against CFA-induced arthritic rats through anti-inflammatory mechanism by regulation of the PPAR-γ. PRACTICAL APPLICATIONS: Increase the arthritis disease worldwide day-by-day. The current research study showed the anti-arthritic effect of farrerol (flavonoid phytoconstituent) of Rhododendron dauricum Linn. In this study, farrerol considerably inhibited the NF-κB to show the anti-arthritic effect. The finding showed the potential effect against acute and chronic inflammation via inhibition of inflammatory mediators and oxidative stress. The result suggests the anti-inflammatory and antioxidant effect of farrerol. On the basis of result, we can say that farrerol can be the beneficial drug to treat the arthritis.

A Complete Study of Farrerol Metabolites Produced in Vivo and in Vitro

Although farrerol, a characteristically bioactive constituent of Rhododendron dauricum L., exhibits extensive biological and pharmacological activities (e.g., anti-oxidant, anti-immunogenic, and anti-angiogenic) as well as a high drug development potential, its metabolism remains underexplored. Herein, we employed ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry coupled with multiple data post-processing techniques to rapidly identify farrerol metabolites produced in vivo (in rat blood, bile, urine and feces) and in vitro (in rat liver microsomes). As a result, 42 in vivo metabolites and 15 in vitro metabolites were detected, and farrerol shown to mainly undergo oxidation, reduction, (de)methylation, glucose conjugation, glucuronide conjugation, sulfate conjugation, N-acetylation and N-acetylcysteine conjugation. Thus, this work elaborates the metabolic pathways of farrerol and reveals the potential pharmacodynamics forms of farrerol.

Magnetic molecularly imprinted polymers doped with graphene oxide for the selective recognition and extraction of four flavonoids from Rhododendron species

Herein, a novel magnetic molecularly imprinted polymer doped with reticular graphene oxide (Fe₃O₄@SiO₂-GO@MIPs) was synthesized for the selective recognition and extraction of 4 flavonoids (farrerol, taxifolin, kaempferol, and hyperin) from Rhododendrons species. The Fe₃O₄@SiO₂-GO@MIPs with lamellar membranes showed outstanding adsorption capacity. The 3D cavities complementary to the "shape" of farrerol were "imprinted" on the polymer framework after removal of farrerol template. Competitive binding assays showed that the polymer has a higher selectivity for farrerol compared with other analogues and references. The Fe₃O₄@SiO₂-GO@MIPs as solid-phase extraction adsorbents combined with liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) was used for selective determination of four flavonoids from Rhododendrons samples. The limits of detection (LOD) were 0.07, 0.08, 0.06, and 0.08 μg L^-1 for farrerol, taxifolin, kaempferol, and hyperin, respectively. These results suggest that the prepared Fe₃O₄@SiO₂-GO@MIPs have the potential applicability to extract, purify, and enrich flavonoids from herbs, supplements, and other natural products.