Pre-column derivatization combined with UHPLC–MS/MS for rapid and sensitive quantification of bakuchiol in rat plasma

Multi-technology integrated network pharmacology-based study on phytochemicals, active metabolites, and molecular mechanism of Psoraleae Fructus to promote melanogenesis

ETHNOPHARMACOLOGICAL RELEVANCE

According to the Compendium of Materia Medica (Shizhen Li, Ming dynasty) and Welfare Pharmacy (Song dynasty), Psoraleae Fructus (PF), a traditional Chinese medicine (TCM) has a bitter taste and warm nature, which has the effect of treating spleen and kidney deficiency and skin disease. Although PF has been widely used since ancient times and has shown satisfactory efficacy in treating vitiligo, the active substances and the mechanism of PF in promoting melanogenesis remain unclear.

AIM OF THE STUDY

To explore the active substances and action mechanisms of PF in promoting melanogenesis.

MATERIALS AND METHODS

Firstly, UPLC-UV-Q-TOF/MS was used to characterize the components in PF extract and identify the absorption components and metabolites of PF after oral administration at usual doses in rats. Secondly, the active substances and related targets and pathways were predicted by network pharmacology and molecular docking. Finally, pharmacodynamic and molecular biology experiments were used to verify the prediction results.

RESULTS

The experimental results showed that 15 compounds were identified in PF extract, and 44 compounds, consisting of 8 prototype components and 36 metabolites (including isomers) were identified in rats' plasma. Promising action targets (MAPK1, MAPK8, MAPK14) and signaling pathways (MAPK signaling pathway) were screened and refined to elucidate the mechanism of PF against vitiligo based on network pharmacology. Bergaptol and xanthotol (the main metabolites of PF), psoralen (prototype drug), and PF extract significantly increased melanin production in zebrafish embryos. Furthermore, bergaptol could promote the pigmentation of zebrafish embryos more than psoralen and PF extract. Bergaptol significantly increased the protein expression levels of p-P38 and decreased ERK phosphorylation in B16F10 cells, which was also supported by the corresponding inhibitor/activator combination study. Moreover, bergaptol increased the mRNA expression levels of the downstream microphthalmia-associated transcription factor (MITF) and tyrosinase in B16F10 cells. Our data elucidate that bergaptol may promote melanogenesis by regulating the p-P38 and p-ERK signaling pathway.

CONCLUSIONS

This study will lay a foundation for discovering potential new drugs for treating vitiligo and provide feasible ideas for exploring the mechanism of traditional Chinese medicine.

Design, synthesis and biological evaluation of bakuchiol derivatives as multi-target agents for the treatment of Alzheimer's disease

The concept of multi-target-directed ligands offers fresh perspectives for the creation of brand-new Alzheimer's disease medications. To explore their potential as multi-targeted anti-Alzheimer's drugs, eighteen new bakuchiol derivatives were designed, synthesized, and evaluated. The structures of the new compounds were elucidated by IR, NMR, and HRMS. Eighteen compounds were assayed for acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in vitro using Ellman's method. It was shown that most of the compounds inhibited AChE and BuChE to varying degrees, but the inhibitory effect on AChE was relatively strong, with fourteen compounds showing inhibition of >50% at the concentration of 200 μM. Among them, compound 3g (IC50 = 32.07 ± 2.00 μM) and compound 3n (IC50 = 34.78 ± 0.34 μM) showed potent AChE inhibitory activities. Molecular docking studies and molecular dynamics simulation showed that compound 3g interacts with key amino acids at the catalytically active site (CAS) and peripheral anionic site (PAS) of acetylcholinesterase and binds stably to acetylcholinesterase. On the other hand, compounds 3n and 3q significantly reduced the pro-inflammatory cytokines TNF-α and IL-6 released from LPS-induced RAW 264.7 macrophages. Compound 3n possessed both anti-acetylcholinesterase activity and anti-inflammatory properties. Therefore, an in-depth study of compound 3n is expected to be a multi-targeted anti-AD drug.

Bakuchiol - a natural meroterpenoid: structure, isolation, synthesis and functionalization approaches

Bakuchiol is an emblematic meroterpene class of natural product extracted from Psoralea corylifolia. It has been reported to possess a broad range of biological and pharmacological properties and is considered as a leading biomolecule. It is highly desirable to devise an efficient approach to access bakuchiol and its chemical biology applications. In this review we provided structural features, isolation methods, various chemical routes and late-stage functionalization (LSF) approaches for bakuchiol and its derivatives. Moreover, this review encompasses the structure-activity relationships (SAR), value-added contributions and future perspectives of bakuchiol.

Design, Synthesis, and Biological Evaluation of Membrane-Active Bakuchiol Derivatives as Effective Broad-Spectrum Antibacterial Agents

Infections caused by drug-resistant bacteria seriously endanger human health and global public health. Therefore, it is urgent to discover and develop novel antimicrobial agents to combat multidrug-resistant bacteria. In this study, we designed and synthesized a series of new membrane-active bakuchiol derivatives by biomimicking the structure and function of cationic antibacterial peptides. The most promising compound 28 displayed potent antibacterial activity against both Gram-positive bacteria (minimum inhibitory concentration, MIC = 1.56-3.125 μg/mL) and Gram-negative bacteria (MIC = 3.125 μg/mL), very weak hemolytic activity, and low cytotoxicity. Compound 28 had rapid bactericidal properties and avoided bacterial resistance. More importantly, compound 28 showed strong in vivo antibacterial efficacy against Staphylococcus aureus and Pseudomonas aeruginosa in murine corneal infection models. This design strategy is expected to provide an effective solution to the antibiotic crisis.

Characterization of human UDP-glucuronosyltransferases responsible for glucuronidation and inhibition of norbakuchinic acid, a primary metabolite of hepatotoxicity and nephrotoxicity component bakuchiol inPsoralea corylifolia L

Norbakuchinic acid (NBKA) is the most abundant metabolite of bakuchiol (a hepatotoxicity and nephrotoxicity component inPsoralea corylifoliaL.) in plasma and urine.

Identification of UDP-glucuronosyltransferases 1A1, 1A3 and 2B15 as the main contributors to glucuronidation of bakuchiol, a natural biologically active compound

1. Bakuchiol, one of the main active compounds of Psoralea corylifolia, possesses a variety of pharmacological activities such as anti-tumor and anti-aging effects. Here, we aimed to characterize the glucuronidation of bakuchiol using human liver microsomes (HLM) and expressed UDP-glucuronosyltransferase (UGT) enzymes. 2. The glucuronide of bakuchiol was confirmed by liquid chromatography-mass spectrometry (LC-MS) and β-glucuronidase hydrolysis assay. Glucuronidation rates and kinetic parameters were derived by enzymatic incubation and model fitting. Activity correlation analyses were performed to identify the main UGT isoforms contributing to hepatic metabolism of bakuchiol. 3. Among the three UGT enzymes (i.e., UGT1A1, UGT1A3 and UGT2B15) capable of catalyzing bakuchiol glucuronidation, UGT2B15 showed the highest activity with a CL_int value of 100 μl/min/nmol. Bakuchiol glucuronidation was strongly correlated with glucuronidation of 5-hydroxyrofecoxib (r = 0.933; p < 0.001), 3-O-glucuronidation of β-estradiol (r = 0.719; p < 0.01) and significantly correlated with 24-O-glucuronidation of CDCA (r = 0.594; p < 0.05). In addition, a marked species difference existed in hepatic glucuronidation of bakuchiol. 4. In conclusion, UGT1A1, UGT1A3 and UGT2B15 were identified as the main contributors to glucuronidation of bakuchiol.

High-performance thin-layer chromatography for the evaluation of voacamine intracellular concentration related to its cytotoxic effect

Previous investigations demonstrated that pretreatment with non-cytotoxic concentrations of voacamine had a chemosensitizing effect on cultured multidrug resistant osteosarcoma cells exposed to doxorubicin; whereas when used alone at high concentrations voacamine induced apoptosis-independent cell death on both sensitive and resistant cells. To gain insight into the mechanism of action of voacamine at the subcellular level, we developed an analytical high-performance thin-layer chromatography technique to assess the intracellular content of voacamine that could be correlated with the induction of cell death and consequent morphological and ultrastructural changes. The results of the quantitative analysis not only did allow us to measure both the amount of unmodified voacamine molecules (determined by the method) and the amount of molecules which reacted with cellular components (undetectable), but also to confirm the findings of our previous studies and support the validity of this method.

Characterization of Compounds in Psoralea corylifolia Using High-Performance Liquid Chromatography Diode Array Detection, Time-of-Flight Mass Spectrometry and Quadrupole Ion Trap Mass Spectrometry

High-performance liquid chromatography with diode array detection (HPLC-DAD), time-of-flight mass spectrometry (HPLC-TOFMS) and quadrupole ion trap mass spectrometry (HPLC-QITMS) were used for separation and identification of multi-components in Psoralea corylifolia. Benefiting from combining the accurate mass measurement of HPLC-TOFMS to generate elemental compositions, the complementary multilevel structural information provided by HPLC-QITMS and the characteristic UV spectra obtained from HPLC-DAD, 24 components in P. corylifolia were identified. The five groups of isomers were differentiated based on the fragmentation behaviors in QITMS and UV spectra. It can be concluded that an effective method based on the combination of HPLC-DAD, HPLC-TOFMS and HPLC-QITMS for identification of chemical components in P. corylifolia was established. The results provide essential data for further pharmacological and clinical studies of P. corylifolia and facilitate the rapid quality control of the crude drug.

Self-micro emulsifying formulation improved intestinal absorption and oral bioavailability of bakuchiol

Bakuchiol (BAK), isolated from the seeds of Psoralea corylifolia L., recently presents a variety of pharmacologic activities. However, the poor oral bioavailability limits its further development and clinical use. The purpose of this study was to establish a self-microemulsifying (SME) formulation for oral delivery improvement of BAK. The optimized liquid SME formulation was comprised of BAK (40 %), Cremophor RH 40 (30 %) and Labrasol (30 %). The emulsion droplets were spherical in shape, and particle size and zeta potential were determined. The in vitro dissolution test of BAK-SME formulation illustrated faster dissolution rate than the bulk drug. The permeabilities of 40 μg mL-1 BAK-SME formulation in rat intestinal segments of duodenum, jejunum, ileum and colon were 30.91 × 10-3, 23.61 × 10-3, 29.43 × 10-3 and 23.62 × 10-3 cm min-1, respectively, exhibiting 3.99 times in duodenum, 2.59 times in ileum and 2.31 times in colon greater than BAK perfusate. The oral bioavailability of BAK-SME formulation at a dose of 150 mg kg-1 was determined in rats. The Cmax and the AUC(0-24h) were 515.4 ng mL-1 and 4,327.2 h ng mL-1, respectively, which were 1.90 fold and 1.73 fold greater than the value of BAK suspension. All these results clearly stated that BAK-SME formulation performed well-improvement on oral bioavailability of BAK.

In vitro evidence for bakuchiol's influence towards drug metabolism through inhibition of UDP-glucuronosyltransferase (UGT) 2B7

BACKGROUND

Inhibition of drug-metabolizing enzymes (DMEs) has been regarded as one of the most important reason for clinical drug-drug interaction.

AIM

The aim of the present study is to evaluate the inhibition of bakuchiol towards UDP-glucuronosyltransferase (UGT) 2B isoforms.

METHODS

In vitro recombinant UGT2B-catalyzed 4-methylumbelliferone glucuronidation was used as the probe reaction. Dixon plot and Lineweaver-Burk plot were employed to determine the inhibition kinetic type, and nonlinear regression of data was utilized to calculate the inhibition kinetic parameter (Ki). In vitro-in vivo extrapolation (IVIVE) was carried out to predict in vivo inhibition magnitude.

RESULTS

Among the tested UGT2B isoforms, UGT2B7 was inhibited by the strongest intensity. The noncompetitive inhibition was demonstrated by the results obtained from Dixon plot and Lineweaver-Burk plot. The Ki value was calculated to be 10.7 µM. In combination with the reported concentration after an intravenous administration of bakuchiol (15 mg/kg) in rats, the high risk of in vivo inhibition of bakuchiol towards UGT2B7-catalyzed metabolism of drugs was indicated.

CONCLUSION

All these results provide an important information for the risk evaluation of the clinical utilization of bakuchiol.

Simultaneous quantification of simvastatin and simvastatin hydroxy acid in blood serum at physiological pH by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS)

Simvastatin attenuates airway inflammation and hyperreactivity, hallmarks of asthma, in allergen-challenged mice. As such, it is under consideration as a novel therapeutic, thus it is important to quantify the levels of simvastatin and its pharmacologically active and interconvertible metabolite, simvastatin hydroxy acid, that can be attained in the body. Methods exist to measure the concentrations of these compounds in biological media; however they do not maintain a physiological pH, and as a result do not accurately measure the ratio of these two compounds that exists in vivo. We developed a new method to measure simvastatin and simvastatin hydroxy acid more accurately in serum from mice by ultra high performance liquid chromatography-tandem mass spectrometry. We minimized the time that the compounds were in aqueous solution, and buffered samples to a physiological pH value of 7.4. Limits of quantification (LOQ) were 0.16 ng mL(-1) extract (1.3 ng mL(-1) serum) for simvastatin, and 8.3 ng mL(-1) extract (66 ng mL(-1) serum) for simvastatin hydroxy acid, respectively. No interconversion was observed, based on spike-and-recovery experiments of solutions containing both compounds. The method was applied using biological samples from mice challenged with house dust mite extract and simultaneously treated with subcutaneous simvastatin injection. Simvastatin hydroxy acid concentrations became significantly increased after a 2 week pre-treatment regime, whereas simvastatin concentrations were below the LOQ for all serum samples.