Modulation of transporter activity of OATP1B1 and OATP1B3 by the major active components of Radix Ophiopogonis

Interaction of the main active components in Shengmai formula mediated by organic anion transporter 1 (OAT1)

ETHNOPHARMACOLOGICAL RELEVANCE

Shengmai formula (SMF) is a classical traditional Chinese medicine prescription, which is widely used in the treatment of cardiovascular and cerebrovascular diseases. Our previous studies have demonstrated that some components in SMF can interact with each other through breast cancer resistance protein, sodium taurocholate co-transporting polypeptide, organic anion transporting polypeptide 1B1 and 1B3. Organic anion transporter 1 (OAT1) is highly expressed in kidney, mediating the elimination of many endogenous and exogenous substances. However, the interaction between the main active components in SMF and OAT1 is not clear.

AIM OF THE STUDY

This study aimed to investigate the interactions of the major bioactive components in SMF mediated by OAT1.

MATERIALS AND METHODS

Four main fractions, namely, ginseng total saponins (GTS), ophiopogon total saponins (OTS), ophiopogon total flavonoids (OTF), fructus schisandrae total lignans (STL), and 12 active components, namely, ginsenoside Rg1, Re, Rd and Rb1, ophiopogonin D and D', methylophiopogonanone A and B, schizandrol A and B, schizandrin A and B, were selected to explore the interactions of SMF with OAT1 using cell and rat models.

RESULTS

The above four main fractions in SMF all exhibited inhibitory effects on the uptake of 6-carboxyfluorescein (6-CF), a classic substrate of OAT1. Among the 12 main effective components, only ginsenoside Re, Rd, and methylophiopogonanone A showed inhibition of 6-CF uptake. Additionally, we found that schizandrin B was transported by HEK293-OAT1 cells, and schizandrin B uptake was markedly inhibited by GTS, OTS, OTF, ginsenoside Re, Rd, and methylophiopogonanone A. In rats, ginsenoside Re, Rd, and methylophiopogonanone A jointly increased the AUC_(0-t), AUC_(0-∞), and C_max of schizandrin B, but they decreased its clearance in plasma and excretion in urine.

CONCLUSIONS

Ginsenoside Re, Rd, and methylophiopogonanone A were the potential inhibitors of OAT1, and may interact with some drugs serving as OAT1 substrates clinically. Schizandrin B was a potential OAT1 substrate, and its OAT1-mediated transport was inhibited by ginsenoside Re, Rd, and methylophiopogonanone A. OAT1-mediated interactions of the main active components in SMF can be regarded as one of the important compatibility mechanisms of traditional Chinese medicine preparations.

Identification of the metabolites of methylophiopogonanone A by ultra-high-performance liquid chromatography combined with high-resolution mass spectrometry

RATIONALE

Methylophiopogonanone A (MOA) is a naturally occurring homoisoflavonoid from the Chinese herb Ophiopogon japonicus, which has been demonstrated to attenuate myocardial apoptosis. However, the metabolism of MOA remains unknown. The goal of the present work was to investigate the in vitro metabolism of MOA using liver microsomes and hepatocytes.

METHODS

The metabolites were generated by incubating MOA with rat, monkey and human liver microsomes or hepatocytes. The resulting samples were analyzed by using a quadrupole-orbitrap high-resolution mass spectrometer. The metabolites were identified through the measurements of the exact mass, elemental composition and product ions.

RESULTS

A total of 15 metabolites were detected and identified. Among these metabolites, M7 (demethylenation) was the most abundant metabolite in liver microsomes, while M6 (hydroxylation) was the predominant metabolite in hepatocytes, and glucuronidation metabolites (M9 and M10) were also the main metabolites in hepatocytes. The metabolic pathways of MOA included hydroxylation, demethylenation, glucuronidation, methylation, sulfation and glutathione conjugation.

CONCLUSIONS

This study for the first time provides valuable data on the metabolites of MOA, which will be of great importance for a better understanding of its disposition and to predict human pharmacokinetics.

Impact of Pineapple Juice on Expression of CYP3A4, NAT2, SULT1A1 and OATP1B1 mRNA in HepG2 Cells

<b>Background and Objective:</b> Pineapple (<i>Ananas comosus</i>) is a popular fruit worldwide with natural antioxidant properties. This study examined how pineapple modified the expression of drug-metabolizing enzymes (CYP1A2, CYP2C9, CYP3A4, UGT1A6, NAT2 and SULT1A1) and a drug transporter (OATP1B1) in human hepatocarcinoma (HepG2) cells. <b>Materials and Methods:</b> HepG2 cells (2.5×10<sup>5</sup> cells/well in a 24-well plate) were incubated with pineapple juice extract (125-1,000 μg mL<sup>1</sup>) for 48 hrs in phenol red-free medium. Resazurin reduction, ROS, AST and ALT assays were performed. The mRNA expression of target genes was determined by RT/qPCR. <b>Results:</b> Pineapple juice slightly reduced HepG2 cell viability to 80% of the control, while ROS, AST and ALT levels were not changed. Pineapple juice did not alter the expression of CYP1A2, CYP2C9 and UGT1A6 mRNA. All tested concentrations of pineapple juice suppressed CYP3A4, NAT2 and OATP1B1 expression, while SULT1A1 expression was induced. <b>Conclusion:</b> Though pineapple juice slightly decreased the viability of HepG2 cells, cell morphology and cell function remained normal. Pineapple juice disturbed the expression of phase I (CYP3A4) and phase II (NAT2 and SULT1A1) metabolizing genes and the drug transporter OATP1B1. Therefore, the consumption of excessive amounts of pineapple juice poses a risk for drug interactions.

Methylophiopogonanone A is a naturally occurring broad-spectrum inhibitor against human UDP-glucuronosyltransferases: Inhibition behaviours and implication in herb-drug interactions

Methylophiopogonanone A (MOA) is an abundant homoisoflavonoid in the Chinese herb Ophiopogonis Radix. Recent investigations revealed that MOA inhibited several human cytochrome P450 enzymes (CYPs) and stimulated OATP1B1. However, the inhibitory effects of MOA on phase II drug-metabolizing enzymes, such as human UDP-glucuronosyltransferases (hUGTs), have not been well investigated. Herein, the inhibition potentials of MOA on hUGTs were assessed. The results clearly demonstrated that MOA dose-dependently inhibited all tested hUGTs including UGT1A1 (IC₅₀  = 1.23 μM), one of the most important detoxification enzymes in humans. Further investigations showed that MOA strongly inhibited UGT1A1-catalysed NHPH-O-glucuronidation in a range of biological settings including hUGT1A1, human liver microsomes (HLM) and HeLa cells overexpressing UGT1A1. Inhibition kinetic analyses demonstrated that MOA competitively inhibited UGT1A1-catalysed NHPH-O-glucuronidation in both hUGT1A1 and HLM, with K_i values of 0.52 and 1.22 μM, respectively. Collectively, our findings expanded knowledge of the interactions between MOA and human drug-metabolizing enzymes, which would be very helpful for guiding the use of MOA-related herbal products in clinical settings.

Reversible and Irreversible Inhibition of Cytochrome P450 Enzymes by Methylophiopogonanone A

Methylophiopogonanone A (MOA), an abundant homoisoflavonoid bearing a methylenedioxyphenyl moiety, is one of the major constituents in the Chinese herb Ophiopogon japonicas This work aims to assess the inhibitory potentials of MOA against cytochrome P450 enzymes and to decipher the molecular mechanisms for P450 inhibition by MOA. The results showed that MOA concentration-dependently inhibited CYP1A, 2C8, 2C9, 2C19, and 3A in human liver microsomes (HLMs) in a reversible way, with IC₅₀ values varying from 1.06 to 3.43 μM. By contrast, MOA time-, concentration-, and NADPH-dependently inhibited CYP2D6 and CYP2E1, along with K_I and k_inact values of 207 µM and 0.07 minute^-1 for CYP2D6, as well as 20.9 µM and 0.03 minutes^-1 for CYP2E1. Further investigations demonstrated that a quinone metabolite of MOA could be trapped by glutathione in an HLM incubation system, and CYP2D6, 1A2, and 2E1 were the major contributors to catalyze the metabolic activation of MOA to the corresponding O-quinone intermediate. Additionally, the potential risks of herb-drug interactions triggered by MOA or MOA-related products were also predicted. Collectively, our findings verify that MOA is a reversible inhibitor of CYP1A, 2C8, 2C9, 2C19, and 3A but acts as an inactivator of CYP2D6 and CYP2E1. SIGNIFICANCE STATEMENT: Methylophiopogonanone A (MOA), an abundant homoisoflavonoid isolated from the Chinese herb Ophiopogon japonicas, is a reversible inhibitor of CYP1A, 2C8, 2C9, 2C19, and 3A but acts as an inactivator of CYP2D6 and CYP2E1. Further investigations demonstrated that a quinone metabolite of MOA could be trapped by glutathione in a human liver microsome incubation system, and CYP2D6, 1A2, and 2E1 were the major contributors to catalyze the metabolic activation of MOA to the corresponding O-quinone intermediate.

Global metabolomic and lipidomic analysis reveals the potential mechanisms of hemolysis effect of Ophiopogonin D and Ophiopogonin D' in vivo

BACKGROUND

OPD and OPD' are the two main active components of Ophiopogon japonicas in Shenmai injection (SMI). Being isomers of each other, they are supposed to have similar pharmacological activities, but the actual situation is complicated. The difference of hemolytic behavior between OPD and OPD' in vivo and in vitro was discovered and reported by our group for the first time. In vitro, only OPD' showed hemolysis reaction, while in vivo, both OPD and OPD' caused hemolysis. In vitro, the primary cause of hemolysis has been confirmed to be related to the difference between physical and chemical properties of OPD and OPD'. In vivo, although there is a possible explanation for this phenomenon, the one is that OPD is bio-transformed into OPD' or its analogues in vivo, the other one is that both OPD and OPD' were metabolized into more activated forms for hemolysis. However, the mechanism of hemolysis in vivo is still unclear, especially the existing literature are still difficult to explain why OPD shows the inconsistent hemolysis behavior in vivo and in vitro. Therefore, the study of hemolysis of OPD and OPD' in vivo is of great practical significance in response to the increase of adverse events of SMI.

METHODS

Aiming at the hemolysis in vivo, this manuscript adopted untargeted metabolomics and lipidomics technology to preliminarily explore the changes of plasma metabolites and lipids of OPD- and OPD'-treated rats. Metabolomics and lipidomics analyses were performed on ultra-high performance liquid chromatography (UPLC) system tandem with different mass spectrometers (MS) and different columns respectively. Multivariate statistical approaches such as principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) were applied to screen the differential metabolites and lipids.

RESULTS

Both OPD and OPD' groups experienced hemolysis, Changes in endogenous differential metabolites and differential lipids, enrichment of differential metabolic pathways, and correlation analysis of differential metabolites and lipids all indicated that the causes of hemolysis by OPD and OPD' were closely related to the interference of phospholipid metabolism.

CONCLUSIONS

This study provided a comprehensive description of metabolomics and lipidomics changes between OPD- and OPD'-treated rats, it would add to the knowledge base of the field, which also provided scientific guidance for the subsequent mechanism research. However, the underlying mechanism require further research.

Differences in the Hemolytic Behavior of Two Isomers in Ophiopogon japonicus In Vitro and In Vivo and Their Risk Warnings

Ophiopogonin D (OPD) and Ophiopogonin D′ (OPD′) are two bioactive ingredients in Ophiopogon japonicus. Previously published studies have often focused on the therapeutic effects related to OPD's antioxidant capacity but underestimated the cytotoxicity-related side effects of OPD′, which may result in unpredictable risks. In this study, we reported another side effect of OPD′, hemolysis, and what was unexpected was that this side effect also appeared with OPD. Although hemolysis effects for saponins are familiar to researchers, the hemolytic behavior of OPD or OPD′ and the interactions between these two isomers are unique. Therefore, we investigated the effects of OPD and OPD′ alone or in combination on the hemolytic behavior in vitro and in vivo and adopted chemical compatibility and proteomics methods to explain the potential mechanism. Meanwhile, to explain the drug-drug interactions (DDIs), molecular modeling was applied to explore the possible common targets. In this study, we reported that OPD′ caused hemolysis both in vitro and in vivo, while OPD only caused hemolysis in vivo. We clarified the differences and DDIs in the hemolytic behavior of the two isomers. An analysis of the underlying mechanism governing this phenomenon showed that hemolysis caused by OPD or OPD′ was related to the destruction of the redox balance of erythrocytes. In vivo, in addition to the redox imbalance, the proteomics data demonstrated that lipid metabolic disorders and mitochondrial energy metabolism are extensively involved by hemolysis. We provided a comprehensive description of the hemolysis of two isomers in Ophiopogon japonicus, and risk warnings related to hemolysis were presented. Our research also provided a positive reference for the development and further research of such bioactive components.

Impact of Pineapple on Mitochondrial Permeability Transition and Drug Metabolizing Genes in Caco-2 Cells

<b>Background and Objective:</b> Pineapple (<i>Ananas comosus</i> L.) has antioxidant and other pharmacological properties. This study examined how pineapple modified mitochondrial permeability transition and expression of drug-metabolizing enzymes, i.e., CYP1A2, CYP2C9, CYP3A4, UGT1A6, NAT2 and the drug transporter OATP1B1 in human colorectal adenocarcinoma (Caco-2) cells. <b>Materials and Methods:</b> Caco-2 cells (2.5×10<sup>5</sup> cells well<sup>1</sup> in 24-well plates) were incubated with pineapple (125 to 1,000 μg mL<sup>1</sup>) for 48 hrs in a phenol red-free medium. Mitochondrial permeability transition, resazurin cell viability and AST and ALT levels were investigated. The mRNA expression of target genes was determined by RT/qPCR. <b>Results:</b> Pineapple significantly reduced depolarized mitochondria, slightly decreased cell viability and did not change AST and ALT levels. Pineapple did not modify the mRNA expressions of CYP1A2, CYP2C9 and CYP3A4 but markedly induced UGT1A6 expression. The highest tested concentration of pineapple (1,000 μg mL<sup>1</sup>) significantly suppressed NAT2 and OATP1B1 expression. <b>Conclusion:</b> Although pineapple slightly decreased cell viability to ~80% of control, the morphology and functions of the cells were unaffected. Pineapple showed a beneficial effect to reduce depolarized mitochondria, which consequently decreased reactive oxygen species production. Pineapple did not modify the expression of CYPs, whilst it altered the expression of phase 2 metabolizing genes UGT1A6 and NAT2 and the transporter OATP1B1. Therefore, the consumption of large amounts of pineapple is of concern for the risk of drug interaction via alteration of UGT1A6, NAT2 and OATP1B1 expression.

A stepwise integrated multi-system to screen quality markers of Chinese classic prescription Qingzao Jiufei decoction on the treatment of acute lung injury by combining 'network pharmacology-metabolomics-PK/PD modeling'

BACKGROUND

Previously, we have investigated the therapeutic mechanism of Qingzao Jiufei Decoction (QZJFD), a Chinese classic prescription, on acute lung injury (ALI), however, which remained to be further clarified together with the underlying efficacy related compounds for quality markers (Q-markers).

HYPOTHESIS/PURPOSE

To explore Q-markers of QZJFD on ALI by integrating a stepwise multi-system with 'network pharmacology-metabolomics- pharmacokinetic (PK)/ pharmacodynamic (PD) modeling'.

METHODS

First, based on in vitro and in vivo component analysis, a network pharmacology strategy was developed to identify active components and potential action mechanism of QZJFD on ALI. Next, studies of poly-pharmacology and non-targeted metabolomics were used to elaborate efficacy and verify network pharmacology results. Then, a comparative PK study on active components in network pharmacology was developed to profile their dynamic laws in vivo under ALI, suggesting Q-marker candidates. Next, quantified analytes with marked PK variations after modeling were fitted with characteristic endogenous metabolites along drug concentration-efficacy-time curve in a PK-PD modeling to verify and select primary effective compounds. Finally, Q-markers were further chosen based on representativeness among analytes through validity analysis of PK quantitation of primary effective compounds.

RESULTS

In virtue of 121 and 33 compounds identified in vitro and in vivo, respectively, 33 absorbed prototype compounds were selected to construct a ternary network of '20 components-47 targets-113 pathways' related to anti-ALI of QZJFD. Predicted mechanism (leukocytes infiltration, cytokines, endogenous metabolism) were successively verified by poly-pharmacology and metabolomics. Next, 18 measurable components were retained from 20 analytes by PK comparison under ALI. Then, 15 primary effective compounds from 18 PK markers were further selected by PK-PD analysis. Finally, 9 representative Q-markers from 15 primary effective compounds attributed to principal (chlorogenic acid), ministerial (methylophiopogonanone A, methylophiopogonanone B), adjuvant (sesamin, ursolic acid, amygdalin), conductant drugs (liquiritin apioside, liquiritigenin and isoliquiritin) in QZJFD, were recognized by substitutability and relevance of plasmatic concentration at various time points.

CONCLUSION

9 Q-markers for QZJFD on ALI were identified by a stepwise integration strategy, moreover, which was a powerful tool for screening Q-makers involved with the therapeutic action of traditional Chinese medicine (TCM) prescription and promoting the process of TCM modernization and scientification.