In vitro investigation of permeability and metabolism of licoricidin

Species Difference in the Metabolism of Mulberrin in Vitro and Its Inhibitory Effect on Cytochrome P450 and UDP-Glucuronosyltransferase Enzymes

This study aimed to evaluate the interspecies difference in metabolism of mulberrin and examine the interaction between mulberrin and CYP enzymes or recombinant human uridine 5'-diphosphate (UDP)-glucuronosyltransferase (UGT) enzymes. Liver microsomes from human (HLMs), Beagle dog (DLMs), minipig (PLMs), monkey (MLMs), rabbit (RLMs), rat (RAMs), and mouse (MIMs) were used to investigate metabolic diversity among different species. Additionally, recombinant human supersomes were used to confirm that metabolic enzymes are involved in the biotransformation of mulberrin. We also evaluated the influence of mulberrin on protein expression by Western blot analysis. Mulberrin metabolism showed significant interspecies differences. We found four and two metabolites in phase I and II reaction systems, respectively. In phase I metabolism profiles of mulberrin for HLMs, PLMs and MLMs conformed to the classic Michaelis-Menten kinetics, RAMs and MIMs followed biphasic kinetics; phase II reaction of mulberrin in HLMs, DLMs, PLMs, MLMs, RLMs, RAMs and MIMs followed biphasic kinetics. UGT1A1 were the major CYP isoforms responsible for the metabolism of mulberrin. Mulberrin showed potent inhibitory effects against CYP3A4, CYP2C9, CYP2E1, UGT1A1, UGT1A3 and UGT2B7 with IC₅₀ values of 54.21, 9.93, 39.12, 3.84, 2.01, 16.36 µM, respectively. According to Western blot analysis, mulberrin can upregulate the protein expression of CYP2C19, and downregulate the expression levels of CYP3A5 and CYP2C9 in HepG2 cells as concentration increased. The interspecies comparisons can help find other species with metabolic pathways similar to those in humans for future in vivo studies.

Metabolism of gartanin in liver microsomes and its modulating effects on cytochrome P450s

Gartanin, a compound found in mangosteen, has various pharmacological activities, including anticancer, anti-inflammation, and antioxidation.In the present study, we reported differences of gartanin metabolism among species and the effect of gartanin on cytochrome P450 (CYP) activities and protein expression.We found significant difference in gartanin metabolism among species, where rabbits and humans had similar metabolic characteristics. Five CYP-catalysed metabolites and three glucuronosyltransferase (UGT)-catalysed metabolites were identified by LC-MS/MS. Hydroxylation was the major metabolic pathway. Gartanin exhibited mixed inhibition on CYP1A2 activity with IC₅₀ and K_i values of 1.48 and 3.71 μM, respectively. In addition, gartanin down-regulated the protein expressions of CYP2C9 and CYP2D6 and up-regulated the protein expression of CYP2D6. The present study supports the pharmacological and toxicological research of gartanin.

An In Vitro Study for Evaluating Permeability and Metabolism of Kurarinone

Kurarinone is a major component found in the dried roots of Sophora flavescens Ait. that participates in vital pharmacological activities. Recombinant CYP450 supersomes and liver microsomes were used to study the metabolic profiles of kurarinone and its inhibitory actions against cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) enzymes. 100 μM of kurarinone strongly inhibited more than 90% of UGT1A1, UGT1A6, CYP1A2, and CYP2C9. CYP1A2 and CYP2D6 played important roles in catalyzing the biotransformation of kurarinone. Moreover, metabolism of kurarinone considerably differs among species, and metabolic characteristics were similar between monkey and human. Kurarinone demonstrated moderate permeability at values of pH 4.0 and 7.4. Our findings offer a clearer idea to understand the pharmacological and toxicological mechanisms of kurarinone.

Licoricidin improves neurological dysfunction after traumatic brain injury in mice via regulating FoxO3/Wnt/β-catenin pathway

Traumatic brain injury (TBI) is a major cause of death and disability around the world with no effective treatments currently. The present study was aimed to investigate the neuroprotective effect of licoricidin, one of the major components of licorice extract, on TBI mice and further explore the underlying mechanism. Male C57BL/6 mice were modeled by a modified weight-drop method to mimic TBI. All animals received treatment 30 min after TBI. The modified Neurological Severity Score (NSS) tests were performed at 2 h and 1-3 days after TBI. The brain edema was analyzed by dry-wet weight method. The malonaldehyde (MDA) levels and the activities of glutathione peroxidase (GSH-PX), superoxide dismutase (SOD) and catalase (CAT) were determined by Elisa. Apoptotic neurons were detected using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) immunofluorescence and the expression of apoptotic proteins were measured by western blot. Activation of the FoxO3/Wnt/β-catenin was evaluated by western blot. The results showed that treatment with licoricidin could significantly decline the NSS scores and reduce the brain edema, hence promote the recovery of neurological function in TBI mice. It also elevated the phosphorylation of p66^shc, brought down the levels of MDA, as well as antagonized the decrement in activities of GSH-PX, SOD and CAT induced by TBI. Moreover, licoricidin decreased the TUNEL positive neurons, downregulated the expression of Cyt-C, cleaved-Caspase-3, cleaved-Caspase-9 and Bax and upregulated the Bcl-2, attenuated cellular apoptosis. Licoricidin decreased the expression of FoxO3 and increased the Wnt/β-catenin in TBI mice. In conclusion, Licoricidin exerted neuroprotective effect on TBI model and the effect was possibly due to its antioxidative effect and antiapoptotic effect via regulating the FoxO3/Wnt/β-catenin pathway. Licoricidin may be a candidate drug for TBI therapy.

Interspecies metabolic diversity of artocarpin in vitro mammalian liver microsomes

Artocarpin has shown anti-inflammation and anticancer activities. However, the metabolism differences among different species have not been reported. In this work, we used liver microsomes to explore the metabolic characteristics and possible metabolites of artocarpin among different species. The structures of six metabolites were characterized by LC-MS/MS, and hydroxylated artocarpin was the main metabolite. Enzyme kinetics and depletion studies of artocarpin among different species proved that artocarpin metabolism exhibited significant species differences; rats and monkeys showed a great metabolic ability to artocarpin, and minipigs showed the highest similarity to humans. The in vivo hepatic clearances of artocarpin in rats and humans were predicted that artocarpin was classified as a high-clearance drug in humans and rats. The glucuronidation assay of artocarpin in different liver microsomes also proved that artocarpin metabolism showed significant species difference. These findings will support further pharmacological or toxicological research on artocarpin.Abbreviations: UGT: UDP-glucuronosyltransferase; CYP: cytochrome P450; LC-MS/MS: liquid chromatography-tandem mass spectrometry; HPLC: high-performance liquid chromatography; HLMs: human liver microsomes; MLMs: monkey liver microsomes; RAMs: rabbit liver microsomes; RLMs: rat liver microsomes; DLMs: dog liver microsomes; PLMs: minipig liver microsomes; V_max: maximum velocity; K_m: Michaelis constant; CL_int: intrinsic clearance; CL_H: hepatic clearance; Q_H: hepatic blood flow.