Identification of natural products as modulators of OATP2B1 using LC-MS/MS to quantify OATP-mediated uptake

18β-Glycyrrhetinic acid synergizes with enzalutamide to counteract castration-resistant prostate cancer by inhibiting OATP2B1 uptake of dehydroepiandrosterone sulfate

Androgen dependence is a key feature of prostate cancer, and androgen deprivation is effective in treating prostate cancer. However, the disease often worsens and develops into castration-resistant prostate cancer after short-term control. The current study aimed to explore the mechanism of the synergistic action of 18β-glycyrrhetinic acid (18β-GA) and enzalutamide (ENZ) against prostate cancer. Our findings showed that 18β-GA significantly inhibited the expression of OATP2B1 and the transport of dehydroepiandrosterone sulfate (DHEAS) in LNCap and 22RV1 cells. It also downregulated the expression of androgen receptor (AR) to some extent. ENZ strongly inhibited AR expression, but it did not affect OATP2B1-mediated uptake of DHEAS. Compared to the effects of 18β-GA and ENZ alone, the combination of 18β-GA and ENZ significantly enhanced the inhibitory effects on AR, prostate-specific antigen (PSA) expression, tumor cell proliferation, and migration. The results obtained in castrated model mice matched the findings of in vitro experiments. 18β-GA significantly reduced the uptake of DHEAS mediated by OATP2B1 in mouse tumor tissues and cooperated with ENZ to further inhibit the expression of AR and PSA, combat the growth of tumor cells, and promote the apoptosis of tumor cells. In conclusion, 18β-GA considerably decreased the uptake of DHEAS and androgen production in cells by inhibiting the transport function of OATP2B1, while ENZ inhibited the nuclear translocation of AR and reduced the expression of AR. The combination of 18β-GA and ENZ can simultaneously inhibit androgen production and AR expression and exhibit a synergistic effect against castration and prostate cancer progression.

A comprehensive review on pharmacokinetic mechanism of herb-herb/drug interactions in Chinese herbal formula

Oral administration of Chinese Herbal Medicine (CHM) faces various challenges in reaching the target organs including absorption and conversion in the gastrointestinal tract, hepatic metabolism via the portal vein, and eventual systemic circulation. During this process, factors such as gut microbes, physical or chemical barriers, metabolic enzymes, and transporters play crucial roles. Particularly, interactions between different herbs in CHM have been observed both in vitro and in vivo. In vitro, interactions typically manifest as detectable physical or chemical changes, such as facilitating solubilization or producing precipitates when decoctions of multiple herbs are administered. In vivo, such interactions cause alterations in the ADME (absorption, distribution, metabolism, and excretion) profile on metabolic enzymes or transporters in the body, leading to competition, antagonism, inhibition, or activation. These interactions ultimately contribute to differences in the therapeutic and pharmacological effects of multi-herb formulas in CHM. Over the past two thousand years, China has cultivated profound expertise and solid theoretical frameworks over the scientific use of herbs. The combination of multiple herbs in one decoction has been frequently employed to synergistically enhance therapeutic efficacy or mitigate toxic and side effects in clinical settings. Additionally combining herbs with increased toxicity or decreased effect is also regarded as a remedy, a practice that should be approached with caution according to Traditional Chinese Medicine (TCM) physicians. Such historical records and practices serve as a foundation for predicting favorable multi-herb combinations and their potential risks. However, systematic data that are available to support the clinical practice and the exploration of novel herbal formulas remain limited. Therefore, this review aims to summarize the pharmacokinetic interactions and mechanisms of herb-herb or herb-drug combinations from existing works, and to offer guidance as well as evidence for optimizing CHM and developing new medicines with CHM characteristics.

The Use of an Antioxidant Enables Accurate Evaluation of the Interaction of Curcumin on Organic Anion-Transporting Polypeptides 4C1 by Preventing Auto-Oxidation

Flavonoids have garnered attention because of their beneficial bioactivities. However, some flavonoids reportedly interact with drugs via transporters and may induce adverse drug reactions. This study investigated the effects of food ingredients on organic anion-transporting polypeptide (OATP) 4C1, which handles uremic toxins and some drugs, to understand the safety profile of food ingredients in renal drug excretion. Twenty-eight food ingredients, including flavonoids, were screened. We used ascorbic acid (AA) to prevent curcumin oxidative degradation in our method. Twelve compounds, including apigenin, daidzein, fisetin, genistein, isorhamnetin, kaempferol, luteolin, morin, quercetin, curcumin, resveratrol, and ellagic acid, altered OATP4C1-mediated transport. Kaempferol and curcumin strongly inhibited OATP4C1, and the Ki values of kaempferol (AA(-)), curcumin (AA(-)), and curcumin (AA(+)) were 25.1, 52.2, and 23.5 µM, respectively. The kinetic analysis revealed that these compounds affected OATP4C1 transport in a competitive manner. Antioxidant supplementation was determined to benefit transporter interaction studies investigating the effects of curcumin because the concentration-dependent curve evidently shifted in the presence of AA. In this study, we elucidated the food-drug interaction via OATP4C1 and indicated the utility of antioxidant usage. Our findings will provide essential information regarding food-drug interactions for both clinical practice and the commercial development of supplements.

Importance of N-Glycosylation for the Expression and Function of Human Organic Anion Transporting Polypeptide 2B1

Human organic anion transporting polypeptide 2B1 (OATP2B1) is a membrane transporter widely expressed in organs crucial for drug absorption and disposition such as the intestine, liver, and kidney. Evidence indicates that OATP2B1 is a glycoprotein. However, the sites of glycosylation and their contribution to the function and expression of OATP2B1 are largely unknown. In this study, by site-directed mutagenesis, we determined that two of four potential N-glycosylation sites in OATP2B1, N176 and N538, are indeed glycosylated. Functional studies revealed that the transport activities of mutants N176Q and N538Q were greatly reduced as compared to that of wild-type OATP2B1. However, the reduced activity was not due to the impairment of transport function per se but due to the decreased surface expression as the Km and normalized Vmax values of N176Q and N538Q were comparable to those of OATP2B1. Quantitative polymerase chain reaction (PCR) revealed that N176Q and N538Q mutations did not affect the expression of OATP2B1 at a transcriptional level. Immunofluorescence analysis showed that deglycosylated OATP2B1 was largely retained in the endoplasmic reticulum, which may activate the endoplasmic reticulum-associated degradation pathway, and the ubiquitin-proteasome system played a major role in the degradation of OATP2B1. Taken together, OATP2B1 is N-glycosylated, and N-glycosylation is essential for the surface expression of OATP2B1 but not critical for the transport function of OATP2B1 per se.

Investigating the interactions of flavonoids with human OATP2B1: inhibition assay, IC50 determination, and structure-activity relationship analysis

Human organic anion transporting polypeptide 2B1 (OATP2B1) is a crucial transporter for the absorption and disposition of many drugs. Its inhibition by small molecules may alter the pharmacokinetic profile of its substrate drugs. In this study, the interactions of 29 common flavonoids with OATP2B1 were explored using the fluorescent substrate 4',5'-dibromofluorescein and structure-activity relationship analysis. Our results showed that flavonoid aglycones interact with OATP2B1 more strongly than their 3-O- and 7-O-glycoside counterparts, as hydrophilic and bulky groups at these two sites are detrimental to flavonoids' binding with OATP2B1. In contrast, hydrogen-bond forming groups at the C-6 position of ring A and the C-3' and C-4' positions of ring B could strengthen the interaction of flavonoids with OATP2B1. However, a hydroxyl or sugar moiety at the C-8 position of ring A is unfavorable. Our results also indicated that flavones usually interact more strongly with OATP2B1 than their 3-hydroxyflavones (flavonols). The obtained information could be useful for the prediction of additional flavonoids for their interaction with OATP2B1.

OAT, OATP, and MRP Drug Transporters and the Remote Sensing and Signaling Theory

The coordinated movement of organic anions (e.g., drugs, metabolites, signaling molecules, nutrients, antioxidants, gut microbiome products) between tissues and body fluids depends, in large part, on organic anion transporters (OATs) [solute carrier 22 (SLC22)], organic anion transporting polypeptides (OATPs) [solute carrier organic (SLCO)], and multidrug resistance proteins (MRPs) [ATP-binding cassette, subfamily C (ABCC)]. Depending on the range of substrates, transporters in these families can be considered multispecific, oligospecific, or (relatively) monospecific. Systems biology analyses of these transporters in the context of expression patterns reveal they are hubs in networks involved in interorgan and interorganismal communication. The remote sensing and signaling theory explains how the coordinated functions of drug transporters, drug-metabolizing enzymes, and regulatory proteins play a role in optimizing systemic and local levels of important endogenous small molecules. We focus on the role of OATs, OATPs, and MRPs in endogenous metabolism and how their substrates (e.g., bile acids, short chain fatty acids, urate, uremic toxins) mediate interorgan and interorganismal communication and help maintain and restore homeostasis in healthy and disease states.

Pulmonary inflammation caused by cigarette smoke combined with lipopolysaccharide up-regulated OATP2B1 in rat lung tissue and pulmonary epithelial cells

Organic anion transport polypeptide 2B1 (OATP2B1), as an uptake transporter, is involved in the transport of many related substrate drugs and endogenous substances in the lungs. A large amount of data shows that cigarette smoke plays an important role in the occurrence and development of lung diseases such as chronic obstructive pulmonary disease (COPD), asthma and bronchitis. However, the effect of cigarette smoke combined with lipopolysaccharide-induced pulmonary inflammation on the expression of OATP2B1 is not clear. In this study, we used cigarette smoke combined with lipopolysaccharide to establish a lung inflammation model in vivo and in vitro to explore the effect of inflammation on the expression of OATP2B1. Our study found that cigarette smoke combined with lipopolysaccharide-induced pulmonary inflammation upregulated the mRNA and protein expression of OATP2B1 and related inflammatory factors, and the expression level of related proteins was higher with the aggravation of inflammation. The experimental results of animals in vivo were consistent with those of cells in vitro. In summary, these findings provide a model and basis for a follow-up study of the mechanism of OATP2B1 in pulmonary inflammation.

The Challenge and Importance of Integrating Drug-Nutrient-Genome Interactions in Personalized Cardiovascular Healthcare

Despite the rich armamentarium of available drugs against different forms of cardiovascular disease (CVD), major challenges persist in their safe and effective use. These include high rates of adverse drug reactions, increased heterogeneity in patient responses, suboptimal drug efficacy, and in some cases limited compliance. Dietary elements (including food, beverages, and supplements) can modulate drug absorption, distribution, metabolism, excretion, and action, with significant implications for drug efficacy and safety. Genetic variation can further modulate the response to diet, to a drug, and to the interaction of the two. These interactions represent a largely unexplored territory that holds considerable promise in the field of personalized medicine in CVD. Herein, we highlight examples of clinically relevant drug–nutrient–genome interactions, map the challenges faced to date, and discuss their future perspectives in personalized cardiovascular healthcare in light of the rapid technological advances.

Inhibitory Effects of Cranberry Juice and Its Components on Intestinal OATP1A2 and OATP2B1: Identification of Avicularin as a Novel Inhibitor

Organic anion-transporting polypeptide (OATP) 1A2 and OATP2B1 mediate the intestinal absorption of drugs. This study aimed to identify fruit juices or fruit juice components that inhibit OATPs and assess the risk of associated food-drug interactions. Inhibitory potency was assessed by examining the uptake of [³H]estrone 3-sulfate and [³H]fexofenadine into HEK293 cells expressing OATP1A2 or OATP2B1. In vivo experiments were conducted using mice to evaluate the effects of cranberry juice on the pharmacokinetics of orally administered fexofenadine. Of eight examined fruit juices, cranberry juice inhibited the functions of both OATPs most potently. Avicularin, a component of cranberry juice, was identified as a novel OATP inhibitor. It exhibited IC₅₀ values of 9.0 and 37 μM for the inhibition of estrone 3-sulfate uptake mediated by OATP1A2 and OATP2B1, respectively. A pharmacokinetic experiment revealed that fexofenadine exposure was significantly reduced (by 50%) by cranberry juice. Cranberry juice may cause drug interactions with OATP substrates.

The Role of Uptake and Efflux Transporters in the Disposition of Glucuronide and Sulfate Conjugates

Glucuronidation and sulfation are the most typical phase II metabolic reactions of drugs. The resulting glucuronide and sulfate conjugates are generally considered inactive and safe. They may, however, be the most prominent drug-related material in the circulation and excreta of humans. The glucuronide and sulfate metabolites of drugs typically have limited cell membrane permeability and subsequently, their distribution and excretion from the human body requires transport proteins. Uptake transporters, such as organic anion transporters (OATs and OATPs), mediate the uptake of conjugates into the liver and kidney, while efflux transporters, such as multidrug resistance proteins (MRPs) and breast cancer resistance protein (BCRP), mediate expulsion of conjugates into bile, urine and the intestinal lumen. Understanding the active transport of conjugated drug metabolites is important for predicting the fate of a drug in the body and its safety and efficacy. The aim of this review is to compile the understanding of transporter-mediated disposition of phase II conjugates. We review the literature on hepatic, intestinal and renal uptake transporters participating in the transport of glucuronide and sulfate metabolites of drugs, other xenobiotics and endobiotics. In addition, we provide an update on the involvement of efflux transporters in the disposition of glucuronide and sulfate metabolites. Finally, we discuss the interplay between uptake and efflux transport in the intestine, liver and kidneys as well as the role of transporters in glucuronide and sulfate conjugate toxicity, drug interactions, pharmacogenetics and species differences.

Potential Herb-Drug Interactions in the Management of Age-Related Cognitive Dysfunction

Late-life mild cognitive impairment and dementia represent a significant burden on healthcare systems and a unique challenge to medicine due to the currently limited treatment options. Plant phytochemicals have been considered in alternative, or complementary, prevention and treatment strategies. Herbals are consumed as such, or as food supplements, whose consumption has recently increased. However, these products are not exempt from adverse effects and pharmacological interactions, presenting a special risk in aged, polymedicated individuals. Understanding pharmacokinetic and pharmacodynamic interactions is warranted to avoid undesirable adverse drug reactions, which may result in unwanted side-effects or therapeutic failure. The present study reviews the potential interactions between selected bioactive compounds (170) used by seniors for cognitive enhancement and representative drugs of 10 pharmacotherapeutic classes commonly prescribed to the middle-aged adults, often multimorbid and polymedicated, to anticipate and prevent risks arising from their co-administration. A literature review was conducted to identify mutual targets affected (inhibition/induction/substrate), the frequency of which was taken as a measure of potential interaction. Although a limited number of drugs were studied, from this work, interaction with other drugs affecting the same targets may be anticipated and prevented, constituting a valuable tool for healthcare professionals in clinical practice.

The involvement of human organic anion transporting polypeptides (OATPs) in drug-herb/food interactions

Organic anion transporting polypeptides (OATPs) are important transporter proteins that are expressed at the plasma membrane of cells, where they mediate the influx of endogenous and exogenous substances including hormones, natural compounds and many clinically important drugs. OATP1A2, OATP2B1, OATP1B1 and OATP1B3 are the most important OATP isoforms and influence the pharmacokinetic performance of drugs. These OATPs are highly expressed in the kidney, intestine and liver, where they determine the distribution of drugs to these tissues. Herbal medicines are increasingly popular for their potential health benefits. Humans are also exposed to many natural compounds in fruits, vegetables and other food sources. In consequence, the consumption of herbal medicines or food sources together with a range of important drugs can result in drug-herb/food interactions via competing specific OATPs. Such interactions may lead to adverse clinical outcomes and unexpected toxicities of drug therapies. This review summarises the drug-herb/food interactions of drugs and chemicals that are present in herbal medicines and/or food in relation to human OATPs. This information can contribute to improving clinical outcomes and avoiding unexpected toxicities of drug therapies in patients.

Stimulatory effect on the transport mediated by organic anion transporting polypeptide 2B1

Drug-drug interaction (DDI) is one of causes of adverse drug events and can result in life-threatening consequences. Organic anion-transporting polypeptide (OATP) 2B1 is a major uptake transporter in the intestine and contributes to transport various clinically used therapeutic agents. The intestine has a high risk of DDI, because it has a special propensity to be exposed to a high concentration of drugs. Thus, understanding drug interaction mediated by OATP2B1 in the absorption process is important for the prevention of adverse drug events, including decrease in the therapeutic effect of co-administered drugs. Acute drug interaction occurs through the direct inhibitory effect on transporters, including OATP2B1. Moreover, some compounds such as clinically used drugs and food components have an acute stimulatory effect on transport of co-administered drugs by OATP2B1. This review summarizes the acute stimulatory effect on the transport mediated by OATP2B1 and discusses the mechanisms of the acute stimulatory effects of compounds. There are two types of acute stimulatory effects, substrate-independent and -dependent interactions on OATP2B1 function. The facilitating translocation of OATP2B1 to the plasma membrane is one of causes for the substrate-independent acute stimulatory effect. On the contrary, the substrate-dependent effect is based on the direct binding to the substrate-binding site or allosteric progesterone-binding site of OATP2B1.

Investigation of the interactions between flavonoids and human organic anion transporting polypeptide 1B1 using fluorescent substrate and 3D-QSAR analysis

Organic anion transporting polypeptide 1B1 (OATP1B1) is a key hepatic uptake transporter whose inhibition could lead to adverse drug-drug and drug-food interactions. Flavonoids are widely distributed in food and beverages and thus our bodies are frequently exposed to them. Therefore, investigation of the interactions between OATP1B1 and flavonoids could be of great significance. In the present study, 25 common flavonoids were investigated for their interactions with OATP1B1 using the fluorescent substrate 2',7'-dichlorofluorescein (DCF) and three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis. Kinetic study showed that OATP1B1-mediated DCF uptake exhibited a monophasic saturation kinetics with a K_m value of 9.7 ± 2.4 μM. Inhibition assay for flavonoids on OATP1B1-mediated DCF uptake was performed and their IC₅₀ values were determined upon which reliable and predictive CoMFA (q² = 0.604, r² = 0.841) and CoMSIA (q² = 0.534, r² = 0.807) models were developed. Our experimental and computational results showed that flavonoid aglycones interacted with OATP1B1 much stronger than their glycosides such as 3-O- and 7-O-glycosides as bulky hydrophilic and hydrogen-bond forming substituents at C-3 and C-7 positions on rings A and C were unfavorable for their binding. On the other hand, the presence of hydrogen-bond forming groups on ring B was beneficial as long as the number of hydroxyl groups was not >2. Our results also indicated that flavones usually interacted with OATP1B1 much stronger than their 3-hydroxyflavone counterparts (flavonols). The obtained information and 3D-QSAR models could be useful for elucidating and predicting the interactions between flavonoids and human OATP1B1.

β-Glucuronidase- and OATP2B1-mediated drug interaction of scutellarin in Dengzhan Xixin Injection: A formulation aspect

Scutellarin is the major and active constituent of Dengzhan Xixin Injection (DZXX), a traditional Chinese medicine prepared from the aqueous extract of Erigeron breviscapus and widely used for the treatment of various cerebrovascular diseases in clinic. In present study, the possible pharmacokinetic differences of scutellarin after intravenous administration of scutellarin alone or DZXX were explored. Additional, the potential roles of β-glucuronidase (GLU) and OATP2B1 in drug-drug interaction (DDI) between scutellarin and constituents of DZXX were further evaluated in vitro. The plasma concentration, urinary and biliary excretion of scutellarin in rats after administration of DZXX, were significantly higher than those received scutellarin, while pharmacokinetic profile of Apigenin 7-O-glucuronide (AG) in rats was similar no matter AG or DZXX group. Furthermore, higher concentration in brain and plasma, however, lower level of scutellarin in intestine were observed after intravenous administration of DZXX. Finally, AG and caffeoylquinic acid esters were found to significantly inhibit GLU and OATP2B1 in vitro, which might explain, at least in part, the pharmacokinetic DDI between scutellarin and other chemical constituents in DZXX. The findings provided deep insight into the prescription-formulating principle in DZXX for treating the cerebrovascular diseases.

Effects of quercetin on the pharmacokinetics of losartan and its metabolite EXP3174 in rats

1. This study investigates the influence of quercetin on the pharmacokinetics of losartan and its metabolite EXP3174 in rats. 2. The pharmacokinetic profiles of losartan and EXP3174 of orally administered losartan (10 mg/kg) with or without pretreatment with quercetin (20 mg/kg/day for 7 days) were investigated. Additionally, Caco-2 cell transwell model and rat liver microsome incubation experiments were also conducted to investigate its potential mechanism. 3. The results showed that when the rats were pretreated with quercetin, the C_max (2.16 ± 0.40 vs. 1.33 ± 0.21 mg/L) and the AUC_(0-t) (13.89 ± 1.22 vs. 7.34 ± 0.75 mg·h/L) of losartan increased significantly (p < .05), and while the C_max (0.76 ± 0.09 vs. 1.14 ± 0.18 mg/L) of EXP3174 decreased significantly compared to the control (p < .05). The t_1/2 of losartan was prolonged from 3.27 ± 0.45 h to 4.74 ± 0.51 h (p < .05). The results also indicated that quercetin could increase losartan absorption rate by inhibiting the activity of P-gp and decrease its metabolic stability by inhibiting the activity of CYP450 enzyme. 4. These results indicated that the herb-drug interaction between quercetin and losartan might occur when they are co-administered in rats, quercetin could increase the systemic exposure of losartan and decrease the plasma concentration of EXP3174, possibly by inhibiting the activity of P-gp or CYP450 enzyme.

Interactions between crude drug extracts used in Japanese traditional Kampo medicines and organic anion-transporting polypeptide 2B1

ETHNOPHARMACOLOGICAL RELEVANCE

The use of herbal medicines has become popular worldwide, and the information on drug interactions between herbal medicines and chemical drugs is needed.

AIM OF THE STUDY

We screened the inhibitory effects of crude drugs used in Kampo medicines used in Japan on organic anion-transporting polypeptide (OATP) 2B1 to predict potential interactions between Kampo medicines and chemical drugs used together.

MATERIALS AND METHODS

We chose 98 kinds of crude drugs frequently used as ingredients of Kampo formulations in Japan and prepared their boiling water extracts. We then screened their inhibitory effects on OATP2B1 by measuring the uptake of estrone 3-sulphate (E3S) by HEK293 cells stably expressing OATP2B1.

RESULTS

At the concentration of 100µg/ml, the extracts prepared from 12 kinds of crude drugs, Scuteralliae Radix, Arecae Semen, Aurantii Fructus Immaturus, Perillae Herba, Panacis Japonici Rhizoma, Moutan Cortex, Polygalae Radix, Rhei Rhizoma, Cannabis Fructus, Chrysanthemi Flos, Eriobotryae Folium, and Querci Cortex, suppressed the function of OATP2B1 by less than 20%. The extract of bofutsushosan, a representative Kampo formulation, inhibited OATP2B1 function with sufficient levels to suppress absorption of OATP2B1 substrates in clinics. We further evaluated the inhibitory effects of several ingredients containing Rhei Rhizoma, Perillae Herba, and Moutan Cortex on OATP2B1.

CONCLUSIONS

Because of crude drugs used in Kampo medicines might suppress absorption of OATP2B1 substrates, these results may contribute to the safe and effective use of Kampo medicine in clinics. A list of abbreviations: EC, (-)-epicatechin; ECG, epicatechin gallate; EGC, epigallocatechin; EGCG, Epigallocatechin gallate; FBS, fetal bovine serum; grapefruit juice; HEK293, Human embryonic kidney; IC_50, The half inhibitory concentration; OATP, organic anion-transporting polypeptide; β-PGG, penta-O-galloyl-β-D-glucose; t.i.d, 3 times a day.

Honey flavonoids inhibit hOATP2B1 and hOATP1A2 transporters and hOATP-mediated rosuvastatin cell uptake in vitro

1. Some flavonoids contained in the common diet have been shown to interact with important membrane uptake transporters, including organic anion transporting polypeptides (OATPs). OATP2B1 and OATP1A2 expressed in the apical membrane of human enterocytes may significantly contribute to the intestinal absorption of drugs, e.g. statins. This study is aimed at an evaluation of the inhibitory potency of selected food honey flavonoids (namely galangin, myricetin, pinocembrin, pinobanksin, chrysin and fisetin) toward hOATP2B1 and hOATP1A2 as well as at examining their effect on the cellular uptake of the known OATP substrate rosuvastatin. 2. Cell lines overexpressing the hOATP2B1 or hOATP1A2 transporter were employed as in vitro model to determine the inhibitory potency of the flavonoids toward the OATPs. 3. Chrysin, galangin and pinocembrin were found to inhibit both hOATP2B1 and hOATP1A2 in lower or comparable concentrations as the known flavonoid OATP inhibitor quercetin. Galangin, chrysin and pinocembrin effectively inhibited rosuvastatin uptake by hOATP2B1 with IC₅₀ ∼1-10 μM. The inhibition of the hOATP1A2-mediated transport of rosuvastatin by these flavonoids was weaker. 4. The found data indicate that several of the tested natural compounds could potentially affect drug cellular uptake by hOATP2B1 and/or hOATP1A2 at relative low concentrations, a finding which suggests their potential for food-drug interactions.