Intestinal Absorption of Triterpenoids and Flavonoids from Glycyrrhizae radix et rhizoma in the Human Caco-2 Monolayer Cell Model

Gegen Qinlian Decoction Combined with Conventional Western Medicine for the Treatment of Infectious Diarrhea: A Systematic Review and Trial Sequential Analysis

INTRODUCTION

Infectious diarrhea (ID) is a highly prevalent disease worldwide that poses a substantial risk to human well-being. In China, numerous clinical studies have investigated the efficacy of Gegen Qinlian decoction (GGQLD) in treating ID. However, there is a need for additional rigorous and evidence-based medical research to enhance physicians' confidence in their prescribing practices.

METHODS

Seven Chinese and English databases were systematically searched. The Cochrane Risk of Bias tool was used to assess the quality of the included studies. Meta-analysis was conducted using RevMan 5.3, and Stata 16.0 was used for the sensitivity analysis. Trial sequential analysis was performed using TSA v0.9, and GRADEprofiler was utilized to evaluate the quality of evidence.

RESULTS

A total of 12 randomized controlled trials (RCTs) involving 1,240 patients were included. The meta-analysis demonstrated that the combination of GGQLD with conventional Western medicine had better effects on clinical efficacy (relative risk [RR] = 1.15, 95% confidence interval [CI] [1.10, 1.20]), duration of diarrhea symptoms (weighted mean difference [WMD] = -10.96, 95% CI [-11.97, -9.96]), duration of abdominal pain symptoms (WMD = -12.01, 95% CI [-14.12, -9.90]), duration of fever symptoms (WMD = -11.91, 95% CI [-13.39, -10.43]), interleukin-6 levels (WMD = -113.59, 95% CI [-113.03, -108.14]), and tumor necrosis factor-α levels (WMD = -62.18, 95% CI [-65.25, -59.11]) and that no significant adverse reactions occurred (RR = 0.45, 95% CI [0.10, 1.97]). The sample size of the included studies reached the expected size. The quality of evidence for outcome indicators was rated as low or very low.

CONCLUSIONS

The combination of GGQLD with conventional Western medicine demonstrates promising efficacy and safety in treating ID. Nonetheless, more high-quality RCTs are required to confirm this conclusion.

The Role of Licorice Chalcones as Molecular Genes and Signaling Pathways Modulator-A Review of Experimental Implications for Nicotine-Induced Non-Small Cell Lung Cancer Treatment

Lung cancer (LC) represents the leading cause of global cancer deaths, with cigarette smoking being considered a major risk factor. Nicotine is a major hazardous compound in cigarette smoke (CS), which stimulates LC progression and non-small cell lung cancer (NSCLC) specifically through activation of the nicotinic acetylcholine receptor (α7nAChR)-mediated cell-signaling pathways and molecular genes involved in proliferation, angiogenesis, and metastasis. Chalcones (CHs) and their derivatives are intermediate plant metabolites involved in flavonol biosynthesis. Isoliquiritigenin (ILTG), licochalcone A-E (LicoA-E), and echinatin (ECH) are the most common natural CHs isolated from the root of Glycyrrhiza (also known as licorice). In vitro and/or vivo experiments have shown that licorice CHs treatment exhibits a range of pharmacological effects, including antioxidant, anti-inflammatory, and anticancer effects. Despite advances in NSCLC treatment, the mechanisms of licorice CHs in nicotine-induced NSCLC treatment remain unknown. Therefore, the aim of this paper is to review experimental studies through the PubMed/Medline database that reveal the effects of licorice CHs and their potential mechanisms in nicotine-induced NSCLC treatment.

Multienzymatic biotransformation of flavokawain B by entomopathogenic filamentous fungi: structural modifications and pharmacological predictions

BACKGROUND

Flavokawain B is one of the naturally occurring chalcones in the kava plant (Piper methysticum). It exhibits anticancer, anti-inflammatory and antimalarial properties. Due to its therapeutic potential, flavokawain B holds promise for the treatment of many diseases. However, due to its poor bioavailability and low aqueous solubility, its application remains limited. The attachment of a sugar unit impacts the stability and solubility of flavonoids and often determines their bioavailability and bioactivity. Biotransformation is an environmentally friendly way to improve the properties of compounds, for example, to increase their hydrophilicity and thus affect their bioavailability. Recent studies proved that entomopathogenic filamentous fungi from the genera Isaria and Beauveria can perform O-methylglycosylation of hydroxyflavonoids or O-demethylation and hydroxylation of selected chalcones and flavones.

RESULTS

In the present study, we examined the ability of entomopathogenic filamentous fungal strains of Beauveria bassiana, Beauveria caledonica, Isaria farinosa, Isaria fumosorosea, and Isaria tenuipes to transform flavokawain B into its glycosylated derivatives. The main process occurring during the reaction is O-demethylation and/or hydroxylation followed by 4-O-methylglycosylation. The substrate used was characterized by low susceptibility to transformations compared to our previously described transformations of flavones and chalcones in the cultures of the tested strains. However, in the culture of the B. bassiana KCh J1.5 and BBT, Metarhizium robertsii MU4, and I. tenuipes MU35, the expected methylglycosides were obtained with high yields. Cheminformatic analyses indicated altered physicochemical and pharmacokinetic properties in the derivatives compared to flavokawain B. Pharmacological predictions suggested potential anticarcinogenic activity, caspase 3 stimulation, and antileishmanial effects.

CONCLUSIONS

In summary, the study provided valuable insights into the enzymatic transformations of flavokawain B by entomopathogenic filamentous fungi, elucidating the structural modifications and predicting potential pharmacological activities of the obtained derivatives. The findings contribute to the understanding of the biocatalytic capabilities of these microbial cultures and the potential therapeutic applications of the modified flavokawain B derivatives.

Effect of fermentation using different lactic acid bacteria strains on the nutrient components and mineral bioavailability of soybean yogurt alternative

Introduction

Analysis of the composition of yogurt alternatives (YAs) during fermentation provides critical information for evaluating its quality and nutritional attributes.

Method

We investigated the effects of homotypic (HO) and heterotypic (HE) lactic acid bacteria on the nutritional and mineral bioavailabilities of soybean YA (SYA) during fermentation.

Result

The acidic amino acid (Glu, Asp) and organic acid contents in HO-fermented YA were increased from 2.93, 1.71, and 7.43 mg/100 g to 3.23, 1.82, and 73.47 mg/100 g, respectively. Moreover, both HO and HE lactic acid bacteria fermentation enhanced mineral absorptivity. They altered the molecular speciation of minerals from a large molecular type (2,866 Da) to a small molecular type (1,500 Da), which was manifested in a time-dependent manner. Furthermore, YA substantially increased the bone mass in a zebrafish osteoporosis model, further highlighting the potential of lactic acid bacterial fermentation for mineral bioavailability.

Discussion

This study provides a foundation for understanding the effects of fermentation conditions on the composition and bioavailability of minerals in YA and can assist in its production.

Chalcones and Gastrointestinal Cancers: Experimental Evidence

Colorectal (CRC) and gastric cancers (GC) are the most common digestive tract cancers with a high incidence rate worldwide. The current treatment including surgery, chemotherapy or radiotherapy has several limitations such as drug toxicity, cancer recurrence or drug resistance and thus it is a great challenge to discover an effective and safe therapy for CRC and GC. In the last decade, numerous phytochemicals and their synthetic analogs have attracted attention due to their anticancer effect and low organ toxicity. Chalcones, plant-derived polyphenols, received marked attention due to their biological activities as well as for relatively easy structural manipulation and synthesis of new chalcone derivatives. In this study, we discuss the mechanisms by which chalcones in both in vitro and in vivo conditions suppress cancer cell proliferation or cancer formation.

Biological analysis of constituents in Spatholobi Caulis by UFLC-MS/MS: Enhanced quantification and application to permeability properties study in Caco-2 cell monolayer model

Major chemical constituents in medicinal materials are often used as the marker compounds of traditional Chinese medicine (TCM) for treating various diseases. For spatholobi caulis (SPC), it contains a variety of flavones, phenolic acid esters, and lignans which exert many pharmacological effects. However, the absorption and permeability properties of these constituents of SPC are still unclear and require further investigation. Different types and major compounds of SPC were chosen as representative constituents to study their absorption and transepithelial transport characteristics in the human intestinal epithelium-like Caco-2 cell monolayer model. 35 constituents of SPC were evaluated by using ultra fast liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry (UFLC-MS/MS) method, acetonitrile and water containing with 0.5 mM ammonium acetate were used as mobile phase, these analytes with good linear relationships (R² was within 0.9967-0.9998), precision (CV values were less than 10.23 %, LLOQ was less than 13.69 %), accuracy (Mean of inter- and intra-day were within 85.02 %-111.61 % and 85.50-112.97 %, respectively) and stability (The mean was within 85.07 %-113.93 %), among which 16 analytes showed good permeability, 5 analytes were considered to be poorly permeable compounds, and the other 14 analytes were assigned for the moderately absorbed compounds in Caco-2 cell monolayer model. The further results showed that the absorption mechanism of 7 well absorbed compounds, 8-O-methylretusin (1), genistein (7), spasuberol B (16), naringenin (18), isoliquiritigenin (19), 4-hydroxy-3-methoxy cinnamic acid methyl ester (23) and (+)-epipinoresinol (31) in SPC was mainly passive diffusion, their bidirectional transport rate was correlated with the concentration and transport time. The chemical structures of these compounds could affect the permeability properties on the cell monolayer. This study demonstrated the utility of Caco-2 cell monolayer model for evaluating the absorption properties and initial mechanisms of compounds in SPC in vitro, and provided important basis for predicting oral bioavailability of SPC compounds.

Phenolic-rich extract of Nopalea cochenillifera attenuates gastric lesions induced in experimental models through inhibiting oxidative stress, modulating inflammatory markers and a cytoprotective effect

Nopalea cochenillifera (Cactaceae), popularly known as "palma" or "palma doce", is from Mexico, but it was widely introduced in Brazil through crops. It has been used as food and in traditional medicine and is a good source of phenolic compounds. In this study the phytochemical profile and gastroprotective activity of phenolic-rich extract of N. cochenillifera in acute gastric lesion models induced by ethanol and indomethacin were evaluated. High-performance liquid chromatography coupled with mass spectrometry (HPLC/ESI/MSⁿ) allowed the characterization of 12 compounds such as sugars, phenolics and flavonoids. Among polyphenols, the main peak was assigned to isorhamnetin-3-O-(2'',3''-O-di-rhamnose)-glucoside. The TPC and TFC in the dry extract were 67.85 mg of gallic acid equivalent per g/extract and 46.16 mg quercetin equivalent per g/extract, respectively. In the in vitro MTT assay, the extract showed no cytotoxicity and suppressed ROS levels in LPS-treated RAW 264.7 cells. Preclinical models in rats showed that a dose of 100 mg kg^-1 (p < 0.0001) in the ethanol model and doses of 100 mg kg^-1 (p < 0.5) and 200 mg kg^-1 (p < 0.01) in the indomethacin model reduced the gastric lesions. Also, the extract reduced the MPO, MDA, TNF-α and IL-1β levels and increased the GSH and IL-10 levels. The pre-treatment with the extract led to the upregulation of SOD and the downregulation of COX-2 by immunohistochemical analysis. It also showed a cytoprotective effect in the histopathological analysis and stimulated the restoration of the mucus content as observed in the periodic acid-Schiff analysis without modifying the pH, volume or total acidity of the gastric juice. Taken together, N. cochenillifera extract can be applied as a novel gastroprotective ingredient for food or pharmaceutical products.

Gel formulated with Bryophyllum pinnatum leaf extract promotes skin wound healing in vivo by increasing VEGF expression: A novel potential active ingredient for pharmaceuticals

Bryophyllum pinnatum (Crassulaceae) is used in traditional medicine for treating skin wounds. In our previous study, a topical gel containing B. pinnatum aqueous leaf extract showed a preclinical anti-inflammatory effect in in vivo acute edema models. In continuation, the present study aims to evaluate the phytochemical content and the stability of a formulation in gel containing B. pinnatum aqueous leaf extract and its healing properties and mechanism of action through an experimental model of induction of skin wounds in rats and in vitro assays. The animals were treated topically for 7 or 14 days with a formulation in gel containing extract at 5% or a placebo or Fibrinase^® in cream. In addition, to establish some quality control parameters, the total phenolic content (TPC), total flavonoid content (TFC), and a study focusing on the phytochemical and biological stability of a gel for 30 days at two different conditions (room temperature and 40°C/75% RH) were performed. Gel formulation containing extract showed a TPC and TFC of 2.77 ± 0.06 mg of gallic acid/g and 1.58 ± 0.03 mg of quercetin/g, respectively. Regarding the stability study, the formulation in gel showed no significant change in the following parameters: pH, water activity, chromatographic profile, and the content of the major compound identified in the extract. The gel formulation containing extract stimulated skin wound healing while reducing the wound area, as well as decreasing the inflammatory infiltrate, reducing the levels of IL-1β and TNF-α, and stimulating angiogenesis with increased expression of VEGF, an effect similar to Fibrinase. In conclusion, the gel formulation containing extract exhibited relevant skin wound healing properties and, therefore, has the potential to be applied as a novel active ingredient for developing wound healing pharmaceuticals.

18β-Glycyrrhetinic acid altered the intestinal permeability in the human Caco-2 monolayer cell model

PURPOSE

Glycyrrhizin (GL) and its metabolites 18α-glycyrrhetinic acid (18α-GA) and 18β-glycyrrhetinic acid (18β-GA) are used as traditional medicine and food sweeteners. As the major rout of their administration is oral way, therefore their impact on intestinal epithelial cells are investigated.

METHODS

The effects of GL and its metabolites on cell viability using MTT assay, on cytotoxicity using LDH release, on integrity of intestinal epithelial cells by measuring the transepithelial electrical resistance (TEER) and Luciferase permeability tests, on the expression of tight junction proteins at mRNA and protein level by qPCR and western blot techniques, and ultimately on the rate of test compounds absorption via Caco-2 cells monolayer were investigated.

RESULTS

MTT assay showed a concentration- and time-dependent decrease in metabolic activity of Caco-2 cells induced by GL, 18α-GA, and 18β-GA, while only 18β-GA increased the LDH leakage. The monolayer integrity of Caco-2 cells in TEER assay only was affected by 18β-GA. The permeability of paracellular transport marker was increased by 18α-GA and 18β-GA and not GL. In transport studies, only metabolites were able to cross from Caco-2 cells monolayer. qPCR analyses revealed that 18β-GA upregulated the expression of claudin-1 and -4, occludin, junctional adhesion molecules and zonula occludens-1, while 18α-GA upregulated only claudin-4. The expression of claudin-4 at protein level was downregulated non-significantly at 50 μM concentration of 18β-GA.

CONCLUSION

Our results suggest that 18β-GA may cause cellular damages at higher concentrations on gastrointestinal cells and requires a remarkable attention of the nutraceutical and pharmaceutical industries.

Validating the Hypoglycaemic and Hypotensive Roles of Salvia serotina (Chicken Weed) in Normal Healthy Sprague-Dawley Rats

Diabetes mellitus (DM) is an endocrine disease and is characterized by hyperglycaemia. Salvia serotina L. (chicken weed) has been used in traditional medicine to treat various ailments including DM. Aqueous, hexane, ethyl acetate, and methanol crude extracts of S. serotina L. were investigated for their anti-oxidant activities and hypoglycaemic and hypotensive effects in normal, healthy Sprague-Dawley rats using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, oral glucose tolerance test (OGTT), and the CODA noninvasive blood pressure system to determine systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR). The aqueous extract caused a free radical scavenging effect with an IC50 value of 10.2 ± 1.01 µg/mL versus vitamin C (9.42 ± 1.01 µg/mL). The extract lowered the blood glucose concentration at the 150 minute interval (5.00 ± 0.22 mM vs. 6.51 ± 0.33 mM; p = 0.004) and the 180 minute interval (4.77 ± 0.27 mM vs. 5.93 ± 0.0.30 mM; p = 0.015). The hexane extract gave significant hypoglycaemic activity at the 120 minute interval (4.54 ± 0.21 mmol/L vs. 5.50 ± 0.17 mmol/L; p = 0.005). The hexane extract also significantly lowered the SBP (132 ± 6 mm Hg; p = 0.014), DBP (106 ± 7 mm Hg; p = 0.034), and MAP (114 ± 7 mm Hg; p = 0.023) versus the controls SBP (156 ± 4 mm Hg), DBP (132 ± 8 mm Hg), and MAP (140 ± 6 mm Hg). Bioassay-directed purification of the hexane extract yielded 3,7,11-trimethyl-1,6,10-dodecatrien-3-ol (1), 3,7,11-trimethyl-2,6,10-dodecatrien-1-ol (2), and 5,22-stigmastadien-3β-ol (3) as active principles. Hence, S. serotina L. showed anti-oxidant, hypoglycaemic, and hypotensive effects in the rats and may have potential applications in the treatment of diabetes.

Excipient-free nanodispersions dominated by amphiphilic glycosides for bioavailability enhancement of hydrophobic aglycones, a case of glycyrrhetinic acid with diammonium glycyrrhizinate

Natural aglycones, a major ingredient accompanied by glycosides in plants, have played an important role in the treatment of various diseases. However, their bioavailability is limited by their poor water solubility. In contrast to previous efforts that required the use of new exotic materials which may raise concerns about biocompatibility, we report the first case of excipient-free nanodispersions in which an insoluble glycyrrhetinic acid (GA) assembled with its amphiphilic parent drug diammonium glycyrrhizinate (DG) into water-dispersible nanodispersions (130.8 nm for particle size and 91.74% for encapsulation efficiency). This strategy largely increased GA's water apparent solubility by hundreds of times to 549.0 μg/mL with a high cumulative dissolution percentage in vitro greater than 80% in 5 min. The study on the formation mechanism showed that the OH, C-O and C=O group stretching peaks shifted in the FTIR spectra of GA-DG nanodispersions, while the COOH peak (δ _COOH 12.19 ppm) disappeared in the ¹H NMR spectrum of GA-DG nanodispersions, indicating that carboxyl groups on GA may interact with the hydroxyl groups of DG in solution. Molecular dynamics simulations suggested that both hydrophobic interactions and hydrogen-bond interactions contribute to the coassembly of GA and DG molecules in aqueous solution. Oral pharmacokinetic studies in rats demonstrated that such nanodispersions have a significant increase in C_max and AUC_0-t of 2.45- and 3.45-fold compared with those for GA, respectively. Therefore, this strategy, employing amphiphilic glycosides as excipients to prepare nanodispersions, not using new materials, paves the way for the further application of hydrophobic aglycone drugs.

Impact of Drug Metabolism/Pharmacokinetics and their Relevance Upon Traditional Medicine-based anti-COVID-19 Drug Research

BACKGROUND

The representative anti-COVID-19 herbs, i.e. Poria cocos, Pogostemon, Prunus, and Glycyrrhiza plants, are commonly used in the prevention and treatment of COVID-19, a pandemic caused by SARS-CoV-2. Diverse medicinal compounds with favorable anti-COVID-19 activities are abundant in these plants, and their unique pharmacological/pharmacokinetic properties are being revealed. However, the current trends of drug metabolism/pharmacokinetic (DMPK) investigations of anti-COVID-19 herbs have not been systematically summarized.

METHODS

Here, the latest awareness, as well as the perception gaps of DMPK attributes, in the anti-COVID-19 drug development and clinical usage was elaborated and critically commented.

RESULTS

The extracts and compounds of P. cocos, Pogostemon, Prunus, and Glycyrrhiza plants show distinct and diverse absorption, distribution, metabolism, excretion and toxicity (ADME/T) properties. The complicated herb-herb interactions (HHIs) and herb-drug interactions (HDIs) of anti-COVID-19 Traditional Chinese Medicine (TCM) herb pair/formula dramatically influence the PK/pharmacodynamic (PD) performance of compounds thereof, which may inspire researchers to design innovative herbal/compound formulas for optimizing the therapeutic outcome of COVID-19 and related epidemic diseases. The ADME/T of some abundant compounds in anti-COVID-19 plants have been elucidated, but DMPK studies should be extended to more compounds of different medicinal parts, species and formulations, and would be facilitated by various omics platforms and computational analyses.

CONCLUSION

In the framework of systems pharmacology and pharmacophylogeny, the DMPK knowledge base would promote the translation of bench findings into the clinical practice of anti-COVID-19, and speed up the anti-COVID-19 drug discovery and development.

Recent Analytical Approaches for the Study of Bioavailability and Metabolism of Bioactive Phenolic Compounds

The study of the bioavailability of bioactive compounds is a fundamental step for the development of applications based on them, such as nutraceuticals, functional foods or cosmeceuticals. It is well-known that these compounds can undergo metabolic reactions before reaching therapeutic targets, which may also affect their bioactivity and possible applications. All recent studies that have focused on bioavailability and metabolism of phenolic and terpenoid compounds have been developed because of the advances in analytical chemistry and metabolomics approaches. The purpose of this review is to show the role of analytical chemistry and metabolomics in this field of knowledge. In this context, the different steps of the analytical chemistry workflow (design study, sample treatment, analytical techniques and data processing) applied in bioavailability and metabolism in vivo studies are detailed, as well as the most relevant results obtained from them.

Valorisation of liquorice (Glycyrrhiza) roots: antimicrobial activity and cytotoxicity of prenylated (iso)flavonoids and chalcones from liquorice spent (G. glabra, G. inflata, and G. uralensis)

Prenylated phenolics are antimicrobials found in liquorice (Glycyrrhiza spp.).

Gastric Ulcer Healing Property of Bryophyllum pinnatum Leaf Extract in Chronic Model In Vivo and Gastroprotective Activity of Its Major Flavonoid

Gastric ulcer is a common disease that develops complications such as hemorrhages and perforations when not properly treated. Extended use of drugs in the treatment of this pathology can provoke many adverse effects. Therefore, finding medicinal plants with gastroprotective and mucosal healing properties has gained increasing interest. Bryophyllum pinnatum (Crassulaceae), popularly known in Brazil as “saião” or “coirama,” has been used to treat inflammatory disorders. It is rich in flavonoids, and quercetin 3-O-α-L-arabinopyranosyl-(1→2)-O-α-L-rhamnopyranoside-Bp1 is its major compound. In this study, we aimed to investigate ulcer healing properties of B. pinnatum against an acetic acid–induced chronic ulcer model and the gastroprotective activity of Bp1 against gastric lesions induced by ethanol and indomethacin. Ultrafast liquid chromatography was used to quantify the main compounds (mg/g of the extract)—quercetin 3-O-α-L-arabinopyranosyl-(1→2)-O-α-L-rhamnopyranoside (33.12 ± 0.056), kaempferol 3-O-α-L-arabinopyranosyl-(1→2)-O-α-L-rhamnopyranoside (3.98 ± 0.049), and quercetin 3-O-α-L-rhamnopyranoside (4.26 ± 0.022) and showed good linearity, specificity, selectivity, precision, robustness, and accuracy. In vivo studies showed that treatment with the extract at 250 and 500 mg/kg stimulated the healing process in the gastric mucosa with significant ulceration index reduction, followed by improvement in the antioxidant defense system [increased glutathione (GSH) levels, decreased superoxide dismutase upregulation, and malondialdehyde (MDA) levels]. Moreover, the extract decreased interleukin-1β and tumor necrosis factor-a levels and myeloperoxidase (MPO) activity, increased interleukin 10 levels, showed a cytoprotective effect in histological analyzes and also downregulated the expression of cyclooxygenase-2 and NF-κB (p65). The pretreatment with Bp1 at a dose of 5 mg/kg reduced gastric lesions in the ethanol and indomethacin models, increased GSH, and decreased MDA levels. In addition, the pretreatment decreased MPO activity, interleukin-1β and tumor necrosis factor-α levels, while also showing a cytoprotective effect in histological analyzes. Our study suggests that treatment with B. pinnatum extract showed a higher inhibition percentage than pretreatment with the Bp1. This might in turn suggest that Bp1 has gastroprotective activity, but other compounds can act synergistically, potentiating its effect. We conclude that B. pinnatum leaf extract could be a new source of raw material rich in phenolic compounds to be applied in food or medicine.

Advanced approaches for improving bioavailability and controlled release of anthocyanins

Anthocyanins are a group of phytochemicals responsible for the purple or red color of plants. Additionally, they are recognized to have health promoting functions including anti-cardiovascular, anti-thrombotic, anti-diabetic, antimicrobial, neuroprotective, and visual protective effect as well as anti-cancer activities. Thus, consumption of anthocyanin supplement or anthocyanin-rich foods has been recommended to prevent the risk of development of chronic diseases. However, the low stability and bioavailability of anthocyanins limit the efficacy and distribution of anthocyanins in human body. Thus, strategies to achieve target site-local delivery with good bioavailability and controlled release rate are necessary. This review introduced and discussed the latest advanced techniques of designing lipid-based, polysaccharide-based and protein-based complexes, nano-encapsulation and exosome to overcome the limitation of anthocyanins. The improved bioavailability and controlled release of anthocyanins have great significance for gastrointestinal tract absorption, transepithelial transportation and cellular uptake. The techniques of applying different biocompatible materials and modifying the solubility of anthocyanins complex could achieve target site-local delivery with negligible degradation and good bioavailability in human body.

The effect of plant bioactive compounds on lamb performance, intake, gastrointestinal parasite burdens, and lipid peroxidation in muscle

Plant extracts have been widely used in animal production systems due to the benefits promoted by their bioactive components, mainly through their antioxidant effects and positive effects on animal growth, health, and meat quality. We determined whether bioactive compounds (BC) from grape (Vitis vinifera), olive (Olea europaea), and pomegranate (Punica granatum) have beneficial effects on lamb growth while controlling gastrointestinal parasitism and reducing skeletal lipid peroxidation in muscle. Fourteen lambs (4 to 5 mo of age) were housed in individual pens and assigned to two treatment groups (seven animals/group), where they received: 1) a basal diet of beet pulp:soybean meal (90:10) (CONTROL) and 2) the same diet, but containing 0.3% of BC extracted from grape, olive, and pomegranate (BNP). After 21 d of consuming their respective rations (period 1), all lambs were dosed with 10,000 L3 stage larvae of Haemonchus contortus. Intake, production, and physiological parameters were determined before infection (period 1), after oral dosage with L3 (period 2), and during early (period 3) and later (period 4) developmental stages of infection. Groups of animals did not differ in their ration intake or average daily gain, either before or after the infection, or in their parasitic burdens estimated through fecal egg counts (P > 0.05). Lambs under BNP showed greater feed efficiency before infection (P < 0.001), but the pattern reversed after infection. In addition, the inclusion of plant bioactives to the diet did not have an effect (P > 0.05) on blood or lipid peroxidation in muscle or on hemogram, serum concentration of haptoglobin, and immunoglobulin E. These results could be explained by low dietary doses and constrained absorption or ruminal inactivation of these compounds. Changes in feed efficiencies suggest a negative interaction between BC in the diet and parasitism, which warrants further research.

Antihyperglycemic and Lipid Profile Effects of Salvia amarissima Ortega on Streptozocin-Induced Type 2 Diabetic Mice

Salvia amarissima Ortega was evaluated to determinate its antihyperglycemic and lipid profile properties. Petroleum ether extract of fresh aerial parts of S. amarissima (PEfAPSa) and a secondary fraction (F6Sa) were evaluated to determine their antihyperglycemic activity in streptozo-cin-induced diabetic (STID) mice, in oral tolerance tests of sucrose, starch, and glucose (OSTT, OStTT, and OGTT, respectively), in terms of glycated hemoglobin (HbA1c), triglycerides (TG), and high-density lipoprotein (HDL). In acute assays at doses of 50 mg/kg body weight (b.w.), PEfAPSa and F6Sa showed a reduction in hyperglycemia in STID mice, at the first and fifth hour after of treatment, respectively, and were comparable with acarbose. In the sub-chronic test, PEfAPSa and F6Sa showed a reduction of glycemia since the first week, and the effect was greater than that of the acarbose control group. In relation to HbA1c, the treatments prevented the increase in HbA1c. In the case of TG and HDL, PEfAPSa and F6Sa showed a reduction in TG and an HDL increase from the second week. OSTT and OStTT showed that PEfAPSa and F6Sa significantly lowered the postprandial peak at 1 h after loading but only in sucrose or starch such as acarbose. The results suggest that S. amarissima activity may be mediated by the inhibition of disaccharide hydrolysis, which may be associated with an α-glucosidase inhibitory effect.

Traditional Chinese Medicine Li-Zhong-Tang accelerates the healing of indomethacin-induced gastric ulcers in rats by affecting TLR-2/MyD88 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Li-Zhong-Tang (LZT) is a well-known Chinese herbal formulation first described in one of traditional Chinese medicine (TCM) scriptures, Treatise on Febrile Diseases. LZT has been commonly prescribed for the treatment of various gastrointestinal diseases for over 1800 years, and has demonstrated pronounced therapeutic effects on patients with gastric ulcers.

AIM OF THE STUDY

The present study aimed to scientifically evaluate protective effects of LZT on indomethacin (IND)-induced gastric injury in rats and to elucidate whether LZT exerts its gastro-protective effects via enhancing mucosal immunity by regulating TLR-2/MyD88 signaling pathway.

MATERIAL AND METHODS

Gastric ulcers were induced in male Sprague-Dawley (SD) rats with a single oral dose of 150 mg/kg IND. Ulcer index (UI) and curative index (CI) were evaluated. Histopathological examinations were performed and microscopic score (MS) was macroscopically calculated. The volume of gastric juice, free acidity, total acidity, and gastric pH was measured. The gastroprotective and inflammatory biomarkers including levels of nitric oxide (NO), tumor necrosis factor-α (TNF-α), prostaglandin E₂ (PGE₂), and malondialdehyde (MDA) were determined. Expression levels of TLR-2 and MyD88 mRNA were assessed by qRT-PCR. The expression, distribution, and co-localization of TLR-2 and MyD88 protein were determined by Western blot, immunohistochemistry, and immunofluorescence, respectively.

RESULTS

Induction of gastric ulcers in rats resulted in very significantly increased UI and elevated volume and acidity of gastric juice, which were markedly attenuated by LZT treatment. Microscopic examinations of the IND-induced gastric ulcers revealed severe gastric hemorrhagic necrosis, submucosal edema, and destruction of epithelial cells, which were significantly attenuated in LZT-treated rats. Moreover, treatment with LZT remarkably increased gastric mucosal levels of PGE₂ and NO, and lowered highly elevated levels of TNF-α and MDA in gastric ulcerative rats. Mechanistically, LZT inhibited mRNA and protein expression of TLR-2 and MyD88 and enhanced immune function in gastric mucosa. Immunohistochemical analyses and immunofluorescent detection further confirmed a markedly decreased co-localization of TLR-2 and MyD88 protein in the gastric mucosa of LZT-treated rats as compared to that of gastric ulcerative rats.

CONCLUSIONS

These findings indicate that LZT alleviates serious gastric mucosal ulcerations induced by IND. Protective effects of LZT on gastric ulcers are believed to be associated with the intensification of the anti-oxidative defense system, mitigation of proinflammatory cytokines, stimulation of the production of cytoprotective mediators, and improvement of the mucosal immunity through TLR-2/MyD88 signaling pathway.

Metabolic profiling of mice plasma, bile, urine and feces after oral administration of two licorice flavonones

ETHNOPHARMACOLOGICAL RELEVANCE

Licorice is an ancient food and medicinal plant. Liquiritigenin and liquiritin, two kinds of major flavonoes in licorice, are effective substances used as antioxidant, anti-inflammatory and tumor-suppressive food, cosmetics or medicines. However, their in vivo metabolites have not been fully explored.

AIM OF STUDY

To clarify the metabolism of liquiritigenin and liquiritin in mice.

MATERIALS AND METHODS

In this study, we developed a liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry approach to determine the metabolites in mice plasma, bile, urine and feces after oral administration of liquiritigenin or liquiritin. The structures of those metabolites were tentatively identified according to their fragment pathways, accurate masses, characteristic product ions, metabolism laws or reference standard matching.

RESULTS

A total of 26 and 24 metabolites of liquiritigenin or liquiritin were respectively identified. The products related with apigenin, luteolin or quercetin were the major metabolites of liquiritigenin or liquiritin in mice. Seven main metabolic pathways including (de)hydrogenation, (de)hydroxylation, (de)glycosylation, (de)methoxylation, acetylation, glucuronidation and sulfation were summarized to tentatively explain their biotransformation.

CONCLUSION

This study not only can provide the evidence for in vivo metabolites and pharmacokinetic mechanism of liquiritigenin and liquiritin, but also may lay the foundation for further development and utilization of liquiritigenin, liquiritin and then licorice.

Matrix effects of the hydroethanolic extract and the butanol fraction of calyces from Physalis peruviana L. on the biopharmaceutics classification of rutin

OBJECTIVES

The Biopharmaceutics Classification System (BCS) categorizes active pharmaceutical ingredients according to their solubility and permeability properties, which are susceptible to matrix or formulation effects. The aim of this research was to evaluate the matrix effects of a hydroethanolic extract of calyces from Physalis peruviana L. (HEE) and its butanol fraction (BF), on the biopharmaceutics classification of their major compound, quercetin-3-O-rutinoside (rutin, RU).

METHODS

Rutin was quantified by HPLC-UV, and Caco-2 cell monolayer transport studies were performed to obtain the apparent permeability values (P_app ). Aqueous solubility was determined at pH 6.8 and 7.4.

KEY FINDINGS

The P_app values followed this order: BF > HEE > RU (1.77 ± 0.02 > 1.53 ± 0.07 > 0.90 ± 0.03 × 10^-5  cm/s). The lowest solubility values followed this order: HEE > RU > BF (2.988 ± 0.07 > 0.205 ± 0.002 > 0.189 ± 0.005 mg/ml).

CONCLUSIONS

According to these results, rutin could be classified as BCS classes III (high solubility/low permeability) and IV (low solubility/low permeability), depending on the plant matrix. Further work needs to be done in order to establish how apply the BCS for research and development of new botanical drugs or for bioequivalence purposes.

Licochalcone D Induces ROS-Dependent Apoptosis in Gefitinib-Sensitive or Resistant Lung Cancer Cells by Targeting EGFR and MET

Licochalcone D (LCD), a flavonoid isolated from a Chinese medicinal plant Glycyrrhiza inflata, has a variety of pharmacological activities. However, the anti-cancer effects of LCD on non-small cell lung cancer (NSCLC) have not been investigated yet. The amplification of MET (hepatocyte growth factor receptor) compensates for the inhibition of epidermal growth factor receptor (EGFR) activity due to tyrosine kinase inhibitor (TKI), leading to TKI resistance. Therefore, EGFR and MET can be attractive targets for lung cancer. We investigated the anti-proliferative and apoptotic effects of LCD in lung cancer cells HCC827 (gefitinib-sensitive) and HCC827GR (gefitinib-resistant) through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, pull-down/kinase assay, cell cycle analysis, Annexin-V/7-ADD staining, reactive oxygen species (ROS) assay, mitochondrial membrane potential (MMP) assay, multi-caspase assay, and Western blot analysis. The results showed that LCD inhibited phosphorylation and the kinase activity of EGFR and MET. In addition, the predicted pose of LCD was competitively located at the ATP binding site. LCD suppressed lung cancer cells growth by blocking cell cycle progression at the G2/M transition and inducing apoptosis. LCD also induced caspases activation and poly (ADP-ribose) polymerase (PARP) cleavage, thus displaying features of apoptotic signals. These results provide evidence that LCD has anti-tumor effects by inhibiting EGFR and MET activities and inducing ROS-dependent apoptosis in NSCLC, suggesting that LCD has the potential to treat lung cancer.

In vitro and in situ study on characterization and mechanism of the intestinal absorption of 2,3,5,4'-tetrahydroxy-stilbene-2-O-β-D-glucoside

Background

2,3,5,4′-tetrahydroxystilbence-2-O-β-D-glucoside (TSG) is a polyhydroxyphenolic compound, which exhibited a broad spectrum of pharmacological activities, such as anti-inflammatory, anti-depression, anti-oxidation and anti-atherosclerosis. However, the compound had poor bioavailability and the underlying absorption mechanisms had not been studied. Therefore, the purpose of this study was to investigate the intestinal absorption mechanism of TSG.

Methods

This study used Caco-2 cell monolayer model and single-pass intestinal perfusion model to explore the gastrointestinal absorption mechanisms of TSG. The effects of basic parameters such as drug concentration, time and pH on the intestinal absorption of TSG were analyzed by high performance liquid chromatography. The absorption susceptibility of TSG to three inhibitors, P-gp inhibitors verapamil hydrochloride and quinidine, and MRP2 inhibitor probenecid were also assessed.

Results

TSG was poorly absorbed in the intestines and the absorption of TSG in stomach is much higher than that in intestine. Both in vitro and in situ experiments showed that the absorption of TSG was saturated with increasing concentration and it was better absorbed in a weakly acidic environment pH 6.4. Moreover, TSG interacts with P-gp and MRP2, and TSG was not only the substrate of the P-gp and MRP2, but also affected the expression of P-gp and MRP2.

Conclusions

It was concluded that the gastrointestinal absorption the most unique active ingredient and considered as the mechanisms of TSG involved processes passive transport and the participation of efflux transporters.

Antiulcerogenic Activity of Li-Zhong Decoction on Duodenal Ulcers Induced by Indomethacin in Rats: Involvement of TLR-2/MyD88 Signaling Pathway

BACKGROUND

Administration of nonsteroidal anti-inflammatory drugs (NSAIDs) often causes small intestinal ulcers in patients, but few effective drugs are currently available to manage such serious adverse events of NSAIDs. Li-Zhong decoction (LZD), a well-known traditional Chinese medicine (TCM) formula, is commonly prescribed for treatment of gastrointestinal diseases. The present study aimed to investigate the anti-ulcerogenic activity of LZD on indomethacin- (IND-) induced duodenal ulcer in rats. Mechanistic studies of action of LZD were focused on involvement of TLR-2/MyD88 signaling pathway.

METHODS

Fifty male Sprague-Dawley (SD) rats were randomly and evenly divided into five groups: normal control, ulcer control (IND, 25 mg/kg), IND + esomeprazole (ESO, 4.17 mg/kg), and IND + low and high doses of LZD (3.75 and 7.50 g/kg). Macroscopic and histopathological examinations were performed for evaluation of ulcer index (UI), curative index (CI), and microscopic score (MS). Levels of duodenal inflammatory biomarkers and cytoprotective mediators including interleukin-4 (IL-4), IL-10, tumor necrosis factor-α (TNF-α (TNF.

RESULTS

Gross and microscopic examinations of the IND-treated rats revealed severe duodenal hemorrhagic necrosis, inflammatory infiltration, villus destruction, and crypt abscess, while LZD-treated rats manifested these pathological events to a markedly lesser degree. LZD significantly decreased UI and MS, increased CI, preserved the integrity of the villus and crypt, and normalized the tissue architecture of the duodenum of rats. The elevated TNF-α (TNF.

CONCLUSIONS

Our data demonstrate that LZD protects the duodenal mucosa from IND-caused lesions, which is at least partially attributable to the interaction of its potential cytoprotective and anti-inflammatory mechanisms together with enhancement of the mucosal immunity through TLR-2/MyD88 signaling pathway.

The modulatory effect and the mechanism of flavonoids on obesity

With the improvement of living standards, obesity has become a serious health problem all over the word. Currently, the methods and drugs for obesity treatment have some limitations and side effects. Flavonoids are active constituents with various biological activities, widely found in plants, and numerous studies have shown that flavonoids can inhibit obesity and related metabolism disorders effectively. This perspective reviews the recent progress in understanding the anti-obesity effects of flavonoids through modulating food intake, enzyme activities, nutrition absorption, adipogenesis and adipocyte lifecycle, thermogenesis, energy consumption, and intestinal microbiota. PRACTICAL APPLICATIONS: Natural bioactive substance flavonoids have anti-obesity property, which may play a role in anti-obesity drugs or functional food without any side effects. Flavonoids can inhibit weight gain directly or through their biologically active metabolites by various potential pathways. A better understanding of the modulatory effect and the mechanism of flavonoids on obesity will allow us to better utilize flavonoids in plants to treat obesity and related metabolic syndrome.

Molecular transport through primary human small intestinal monolayers by culture on a collagen scaffold with a gradient of chemical cross-linking

BACKGROUND

The luminal surface of the small intestine is composed of a monolayer of cells overlying a lamina propria comprised of extracellular matrix (ECM) proteins. The ECM provides a porous substrate critical for nutrient exchange and cellular adhesion. The enterocytes within the epithelial monolayer possess proteins such as transporters, carriers, pumps and channels that participate in the movement of drugs, metabolites, ions and amino acids and whose function can be regulated or altered by the properties of the ECM. Here, we characterized expression and function of proteins involved in transport across the human small intestinal epithelium grown on two different culture platforms. One strategy employs a conventional scaffolding method comprised of a thin ECM film overlaying a porous membrane while the other utilizes a thick ECM hydrogel placed on a porous membrane. The thick hydrogel possesses a gradient of chemical cross-linking along its length to provide a softer substrate than that of the ECM film-coated membrane while maintaining mechanical stability.

RESULTS

The monolayers on both platforms possessed goblet cells and abundant enterocytes and were impermeable to Lucifer yellow and fluorescein-dextran (70 kD) indicating high barrier integrity. Multiple transporter proteins were present in both primary-cell culture formats at levels similar to those present in freshly isolated crypts/villi; however, expression of breast cancer resistance protein (BCRP) and multidrug resistance protein 2 (MRP2) in the monolayers on the conventional scaffold was substantially less than that on the gradient cross-linked scaffold and freshly isolated crypts/villi. Monolayers on the conventional scaffold failed to transport the BCRP substrate prazosin while cells on the gradient cross-linked scaffold successfully transported this drug to better mimic the properties of in vivo small intestine.

CONCLUSIONS

The results of this comparison highlight the need to create in vitro intestinal transport platforms whose characteristics mimic the in vivo lamina propria in order to accurately recapitulate epithelial function.

GRAPHICAL ABSTRACT

In Vitro and In Situ Characterization of the Intestinal Absorption of Capilliposide B and Capilliposide C from Lysimachia capillipes Hemsl

The goal of this investigation was to determine the processes and mechanism of intestinal absorption for capilliposide B (CAPB) and capilliposide C (CAPC) from the Chinese herb, Lysimachia capillipes Hemsl. An analysis of basic parameters, such as drug concentrations, time, and behavior in different intestinal segments was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS). The susceptibility of CAPB and CAPC to various inhibitors such as P-glycoprotein (P-gp) inhibitor (verapamil); multidrug resistance-associated protein 2 (MRP2) inhibitor (indomethacin); cytochrome P450 protein 3A4 (CYP3A4) inhibitor (ketoconazole); and the co-inhibitor of P-gp, MRP2 and CYP3A4 (cyclosporine A) were assessed using both caco-2 cell monolayer and single-pass intestinal perfusion (SPIP) models. As a result, CAPB and CAPC are both poorly absorbed in the intestines and exhibited segment-dependent permeability. The intestinal permeability of CAPB and CAPC were significantly increased by the co-treatment of verapamil, indomethacin. In addition, the intestinal permeability of CAPB was also enhanced by ketoconazole and cyclosporine A. It can be concluded that the intestinal absorption mechanisms of CAPB and CAPC involve processes such as facilitated passive diffusion, efflux transporters, and enzyme-mediated metabolism. Both CAPB and CAPC are suggested to be substrates of P-gp and MRP2. However, CAPB may interact with the CYP3A4 system.

Elucidation of the Intestinal Absorption Mechanism of Loganin in the Human Intestinal Caco-2 Cell Model

Loganin, iridoid glycosides, is the main bioactive ingredients in the plant Strychnos nux-vomica L. and demonstrates various pharmacological effects, though poor oral bioavailability in rats. In this study, the intestinal absorption mechanism of loganin was investigated using the human intestinal Caco-2 cell monolayer model in both the apical-to-basolateral (A-B) and the basolateral-to-apical (B-A) direction; additionally, transport characteristics were systematically investigated at different concentrations, pHs, temperatures, and potential transporters. The absorption permeability (PappAB) of loganin, which ranged from 12.17 to 14.78 × 10-6cm/s, was high at four tested concentrations (5, 20, 40, and 80μM), while the major permeation mechanism of loganin was found to be passive diffusion with active efflux mediated by multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP). In addition, it was found that loganin was not the substrate of efflux transporter P-glycoprotein (P-gp) since the selective inhibitor (verapamil) of the efflux transporter exhibited little effects on the transport of loganin in the human intestinal Caco-2 cells. Meanwhile, transport from the apical to the basolateral side increased 2.09-fold after addition of a MRP inhibitor and 2.32-fold after addition of a BCRP inhibitor. In summary, our results clearly demonstrate, for the first time, a good permeability of loganin in the human intestinal Caco-2 cell model and elucidate, in detail, the intestinal absorption mechanism and the effects of transporters on iridoid glycosides compounds.

Antioxidant Mechanisms of Echinatin and Licochalcone A

Echinatin and its 1,1-dimethyl-2-propenyl derivative licochalcone A are two chalcones found in the Chinese herbal medicine Gancao. First, their antioxidant mechanisms were investigated using four sets of colorimetric measurements in this study. Three sets were performed in aqueous solution, namely Cu²⁺-reduction, Fe³⁺-reduction, and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-scavenging measurements, while 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•)-scavenging colorimetric measurements were conducted in methanol solution. The four sets of measurements showed that the radical-scavenging (or metal-reduction) percentages for both echinatin and licochalcone A increased dose-dependently. However, echinatin always gave higher IC₅₀ values than licochalcone A. Further, each product of the reactions of the chalcones with DPPH• was determined using electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS). The UPLC-ESI-Q-TOF-MS/MS determination for echinatin yielded several echinatin–DPPH adduct peaks (m/z 662, 226, and 196) and dimeric echinatin peaks (m/z 538, 417, and 297). Similarly, that for licochalcone A yielded licochalcone A-DPPH adduct peaks (m/z 730, 226, and 196) and dimeric licochalcone A peaks (m/z 674 and 553). Finally, the above experimental data were analyzed using mass spectrometry data analysis techniques, resonance theory, and ionization constant calculations. It was concluded that, (i) in aqueous solution, both echinatin and licochalcone A may undergo an electron transfer (ET) and a proton transfer (PT) to cause the antioxidant action. In addition, (ii) in alcoholic solution, hydrogen atom transfer (HAT) antioxidant mechanisms may also occur for both. HAT may preferably occur at the 4-OH, rather than the 4′-OH. Accordingly, the oxygen at the 4-position participates in radical adduct formation (RAF). Lastly, (iii) the 1,1-dimethyl-2-propenyl substituent improves the antioxidant action in both aqueous and alcoholic solutions.

A Monolayer of Primary Colonic Epithelium Generated on a Scaffold with a Gradient of Stiffness for Drug Transport Studies

Animal models are frequently used for in vitro physiologic and drug transport studies of the colon, but there exists significant pressure to improve assay throughput as well as to achieve tighter control of experimental variables than can be achieved with animals. Thus, development of a primary in vitro colonic epithelium cultured as high resistance with transport protein expression and functional behavior similar to that of a native colonic would be of enormous value for pharmaceutical research. A collagen scaffold, in which the degree of collagen cross-linking was present as a gradient, was developed to support the proliferation of primary colonic cells. The gradient of cross-linking created a gradient in stiffness across the scaffold, enabling the scaffold to resist deformation by cells. mRNA expression and quantitative proteomic mass spectrometry of cells growing on these surfaces as a monolayer suggested that the transporters present were similar to those in vivo. Confluent monolayers acted as a barrier to small molecules so that drug transport studies were readily performed. Transport function was evaluated using atenolol (a substrate for passive paracellular transport), propranolol (a substrate for passive transcellular transport), rhodamine 123 (Rh123, a substrate for P-glycoprotein), and riboflavin (a substrate for solute carrier transporters). Atenolol was poorly transported with an apparent permeability ( Papp) of <5 × 10-7 cm s-1, while propranolol demonstrated a Papp of 9.69 × 10-6 cm s-1. Rh123 was transported in a luminal direction ( Papp,efflux/ Papp,influx = 7) and was blocked by verapamil, a known inhibitor of P-glycoprotein. Riboflavin was transported in a basal direction, and saturation of the transporter was observed at high riboflavin concentrations as occurs in vivo. It is anticipated that this platform of primary colonic epithelium will find utility in drug development and physiological studies, since the tissue possesses high integrity and active transporters and metabolism similar to that in vivo.

Sulfation disposition of liquiritigenin in SULT1A3 overexpressing HEK293 cells: The role of breast cancer resistance protein (BCRP) and multidrug resistance-associated protein 4 (MRP4) in sulfate efflux of liquiritigenin

This study aimed to investigate the cellular disposition of liquiritigenin via the sulfonation pathway and the role of efflux transporters in liquiritigenin sulfate excretion. The sulfonation disposition of liquiritigenin was investigated using SULT1A3 overexpressed HEK293 cells (HEK-SULT1A3 cells). Liquiritigenin generated one mono-sulfate metabolite (7-O-sulfate) in HEK-SULT1A3 cell lysate. And the sulfonation followed the Michaelis-Menten kinetic (V_max = 0.84 nmol/min/mg and K_m = 7.12 μM). Expectedly, recombinant SULT1A3 (hSULT1A3) showed a highly similar kinetic profile with cell lysate. Furthermore, 7-O-sulfate was rapidly generated and excreted in HEK-SULT1A3 cells. Ko143 (a BCRP-selective inhibitor) at 20 μM significantly decreased the excretion rate of liquiritigenin sulfate (>42.5%, p < 0.001). Moreover, the pan-MRPs inhibitor MK-571 at 20 μM essentially abolished the liquiritigenin sulfate effluxion, resulting in the marked reduction of excretion rate (>97.4%, p < 0.001). Furthermore, knockdown of BCRP led to moderate reduction in sulfate excretion (15.9%-16.9%, p < 0.05). Silencing of MRP4 caused significant decreased in sulfate excretion (20.2%-32.5%, p < 0.01). In conclusion, one sulfate metabolite was generated from liquiritigenin in HEK-SULT1A3 cells. BCRP and MRP4 should be the key factors for the cellular excretion of liquiritigenin sulfate.