A combined strategy of mass fragmentation, post-column cobalt complexation and shift in ultraviolet absorption spectra to determine the uridine 5'-diphospho-glucuronosyltransferase metabolism profiling of flavones after oral administration of a flavone mixture in rats

Phytochemical Profiling of Lavandula coronopifolia Poir. Aerial Parts Extract and Its Larvicidal, Antibacterial, and Antibiofilm Activity Against Pseudomonas aeruginosa

Infections associated with the emergence of multidrug resistance and mosquito-borne diseases have resulted in serious crises associated with high mortality and left behind a huge socioeconomic burden. The chemical investigation of Lavandulacoronopifolia aerial parts extract using HPLC-MS/MS led to the tentative identification of 46 compounds belonging to phenolic acids, flavonoids and their glycosides, and biflavonoids. The extract displayed larvicidal activity against Culex pipiens larvae (LC50 = 29.08 µg/mL at 72 h). It significantly inhibited cytochrome P-450 monooxygenase (CYP450), acetylcholinesterase (AChE), and carboxylesterase (CarE) enzymes with the comparable pattern to the control group, which could explain the mode of larvae toxification. The extract also inhibited the biofilm formation of Pseudomonas aeruginosa by 17-38% at different Minimum Inhibitory Concentrations (MICs) (0.5-0.125 mg/mL) while the activity was doubled when combined with ciprofloxacin (ratio = 1:1 v:v). In conclusion, the wild plant, L.coronopifolia, can be considered a promising natural source against resistant bacteria and infectious carriers.

Succinic acid inhibits the activity of cytochrome P450 (CYP450) enzymes

CONTEXT

Succinic acid, extracted from amber, is widely used in cardiovascular therapy.

OBJECTIVE

The effect of succinic acid on the activity of cytochrome P450 (CYP450) enzymes was investigated in this study.

MATERIALS AND METHODS

The effect of succinic acid (100 μM) on the activity of eight isoforms of CYP450 (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19 and 2C8) was investigated compared to the specific inhibitor and blank controls in pooled human liver microsomes in vitro. The inhibition of CYPs was fitted with competitive or non-competitive inhibition models and corresponding parameters were also obtained.

RESULTS

Succinic acid exerted inhibitory effect on the activity of CYP3A4, 2D6, and 2C9 with the IC₅₀ values of 12.82, 14.53, and 19.60 μM, respectively. Succinic acid inhibited the activity of CYP3A4 in a non-competitive manner with the Ki value of 6.18 μM, and inhibited CYP2D6 and 2C9 competitively with Ki values of 7.40 and 9.48 μM, respectively. Furthermore, the inhibition of CYP3A4 was found to be time-dependent with the KI/K_inact value of 6.52/0.051 min^-1·μM^-1.

DISCUSSION AND CONCLUSIONS

Succinic acid showed in vitro inhibitory effects on the activity of CYP3A4, 2D6, and 2C9, which indicated the potential drug-drug interactions. Succinic acid should be carefully co-administrated with the drugs metabolized by CYP3A4, 2D6, and 2C9.

Synanthropic Plants as an Underestimated Source of Bioactive Phytochemicals: A Case of Galeopsis bifida (Lamiaceae)

Hemp nettle (Galeopsis bifida Boenn.) is a synanthropic species of the Lamiaceae family that is widely distributed across Europe, Asia, and Siberia. Galeopsis bifida is deeply embedded in the ethnomedical tradition of Asian healers; however, this plant is still poorly characterized, both chemically and pharmacologically. To study Siberian populations of G. bifida, we used high-performance liquid chromatography with photodiode array and electrospray triple quadrupole mass detection for metabolic profiling. Ninety compounds were identified, including iridoid glycosides, phenylethanoid glycosides, hydroxycinnamates, and flavone glycosides, most of which were identified in G. bifida for the first time, while some phenolics were found to have potential chemotaxonomic significance in the Lamiaceae family and Galeopsis genus. An unequal quantitative distribution of the selected metabolites was observed within separate organs of the G. bifida plant, characterized by high accumulation of most compounds within the aerial part of the plant (leaves, flowers). Analysis of the content of specific chosen compounds within the leaves of different populations of G. bifida from Eastern Siberia revealed the existence of two chemical types based on metabolic specifics: the southern type accumulates flavone glucuronides, while the northern type tends to accumulate high levels of phenylpropanoids and acylated flavone glucosides. The first study of the bioactivity of G. bifida extract demonstrated that the herb has low toxicity in acute experiments and expresses antioxidant potential against free radicals in the form of DPPH˙, ABTS˙+, and superoxide radical, as well as high ferric reducing antioxidant power, oxygen radical absorbance capacity, and protective action in the carotene bleaching assay. In general, our results suggest the herb of G. bifida as a new, prospective synanthropic plant for medical application.

Caffeoylquinic Acids and Flavonoids of Fringed Sagewort (Artemisia frigida Willd.): HPLC-DAD-ESI-QQQ-MS Profile, HPLC-DAD Quantification, in Vitro Digestion Stability, and Antioxidant Capacity

Fringed sagewort (Artemisia frigida Willd., Compositae family) is a well-known medicinal plant in Asian medical systems. Fifty-nine hydroxycinnamates and flavonoids have been found in A. frigida herbs of Siberian origin by high-performance liquid chromatography with diode array and electrospray triple quadrupole mass detection (HPLC-DAD-ESI-QQQ-MS). Their structures were determined after mass fragmentation analysis as caffeoylquinic acids, flavone O-/C-glycosides, flavones, and flavonol aglycones. Most of the discovered components were described in A. frigida for the first time. It was shown that flavonoids with different types of substitution have chemotaxonomic significance for species of Artemisia subsection Frigidae (section Absinthium). After HPLC-DAD quantification of 16 major phenolics in 21 Siberian populations of A. frigida and subsequent principal component analysis, we found substantial variation in the selected compounds, suggesting the existence of two geographical groups of A. frigida. The antioxidant activity of A. frigida herbal tea was determined using 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH•) and hydrophilic/lipophilic oxygen radical absorbance capacity (ORAC) assays and DPPH•-HPLC profiling, revealing it to be high. The effect of digestive media on the phenolic profile and antioxidant capacity of A. frigida herbal tea was assessed under simulated gastrointestinal digestion. We found a minor reduction in caffeoylquinic acid content and ORAC values, but remaining levels were satisfactory for antioxidant protection. These results suggest that A. frigida and its food derivate herbal tea could be recommended as new plant antioxidants rich in phenolics.

Use of UHPLC-QTOF-MS/MS with combination of in silico approach for distributions and metabolites profile of flavonoids after oral administration of Niuhuang Shangqing tablets in rats

Niuhuang Shangqing tablet (NHSQT), a well-known traditional Chinese medicine preparation, has been used as an over- the- counter drug for the treatment of headache, dizziness in China. The flavonoids are the main active components in NHSQT, however, there have no reports about their distribution and metabolic fate in vivo after oral administration of NHSQTs so far. An novel UHPLC-QTOF-MS/MS method combined with in silico approach was applied to identify the flavonoids and metabolites profiling in biological samples following oral administration NHSQTs for the first time. As a result, 127 compounds including 34 original compounds of flavonoids and 93 metabolites were identified. There were 20 flavones, 9 flavonols, 4 flavanones and 1 flavan-3, 4-diol found in biological samples. Rutin, wogonoside, apigenin, baicalein, wogonin, oroxylin A, quercetin and acacetin were considered as the potential flavonoids in NHSQT against brain diseases. The docking-based metabolism models were established and applied to propose the sites of hydroxylation of flavonoids, which indicated baicalin was engaged in dihydroxylation at C2', C3', tilianin was engaged in hydroxylation at C3, wogonin and wogonside were engaged in dihydroxylation at C3', C4'. Some novel metabolic pathways were discovered for oroxylin A, acacetin, diosmetin, tilianin. The metabolic spots and pathways of flavonoids vary as much between flavones, flavonols and flavanones. The results presented here would be helpful for the further study of pharmacokinetics and quality control of NHSQT.

Pretreatment with Total Flavonoid Extract from Dracocephalum Moldavica L. Attenuates Ischemia Reperfusion-induced Apoptosis

We previously demonstrated the cardio-protection mediated by the total flavonoid extracted from Dracocephalum moldavica L. (TFDM) following myocardial ischemia reperfusion injury (MIRI). The present study assessed the presence and mechanism of TFDM-related cardio-protection on MIRI-induced apoptosis in vivo. Male Sprague-Dawley rats experienced 45-min ischemia with 12 h of reperfusion. Rats pretreated with TFDM (3, 10 or 30 mg/kg/day) were compared with Sham (no MIRI and no TFDM), MIRI (no TFDM), and Positive (trapidil tablets, 13.5 mg/kg/day) groups. In MIRI-treated rats, high dose-TFDM (H-TFDM) pre-treatment with apparently reduced release of LDH, CK-MB and MDA, enhanced the concentration of SOD in plasma, and greatly reduced the infarct size, apoptotic index and mitochondrial injury. H-TFDM pretreatment markedly promoted the phosphorylation of PI3K, Akt, GSK-3β and ERK1/2 in comparison with the MIRI model group. Western blot analysis after reperfusion also showed that H-TFDM decreased release of Bax, cleaved caspase-3, caspase-7 and caspase-9, and increased expression of Bcl-2 as evident by the higher Bcl-2/Bax ratio. TFDM cardio-protection was influenced by LY294002 (PI3K inhibitor) and PD98059 (ERK1/2 inhibitor). Taken together, these results provide convincing evidence of the benefit of TFDM pretreatment due to inhibited myocardial apoptosis as mediated by the PI3K/Akt/GSK-3β and ERK1/2 signaling pathways.

Effects of Herbal Formulas Bojungikgi-tang and Palmijihwang-hwan on Inflammation in RAW 264.7 Cells and the Activities of Drug-Metabolizing Enzymes in Human Hepatic Microsomes

In the present study, Bojungikgi-tang (BJIKT: Buzhongyiqi-tang, Hochuekki-to) and Palmijihwang-hwan (PMJHH: Baweidìhuang-wan, Hachimijio-gan), traditional herbal formulas, investigated anti-inflammatory efficacies in murine macrophage cell line and the influence on the activities of drug-metabolizing enzymes (DMEs). The anti-inflammatory potentials of the herbal formulas were evaluated to inhibit the production of the inflammatory mediators and cytokines and the protein expression of inducible nitric oxide and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-treated RAW 264.7 cells. The activities of the major human DMEs, cytochrome P450 isozymes (CYP450s) and UDP-glucuronosyltransferase isozymes (UGTs), were measured by in vitro enzyme assay systems. BJIKT and PMJHH significantly suppressed the prostaglandin E₂ (PGE₂) production (IC₅₀ = 317.3 and 282.2 μg/mL, respectively) and the protein expression of COX-2 in LPS-treated RAW264.7 cells. On the human microsomal DMEs, BJIKT inhibited the activities of CYP1A2 (IC₅₀ = 535.05 μg/mL), CYP2B6 (IC₅₀ > 1000 μg/mL), CYP2C9 (IC₅₀ = 800.78 μg/mL), CYP2C19 (IC₅₀ = 563.11 μg/mL), CYP2D6 (IC₅₀ > 1000 μg/mL), CYP2E1 (IC₅₀ > 1000 μg/mL), CYP3A4 (IC₅₀ = 879.60 μg/mL), UGT1A1 (IC₅₀ > 1000 μg/mL), and UGT1A4 (IC₅₀ > 1000 μg/mL), but it showed no inhibition of the UGT2B7 activity at doses less than 1000 μg/mL. PMJHH inhibited the CYP2D6 activity (IC₅₀ = 280.89 μg/mL), but IC₅₀ values of PMJHH exceeded 1000 μg/mL on the activities of CYP1A2, CYP2C19, CYP2E1, and CYP3A4. At concentrations less than 1000 μg/mL, PMJHH did not affect the activities of CYP2B6, CYP2C9, UGT1A1, UGT1A4, and UGT2B7. The results indicate that both BJIKT and PMJHH may be potential candidates to prevent and treat PGE₂- and COX-2-mediated inflammatory diseases. In addition, this study will expand current knowledge about herb-drug interactions by BJIKT and PMJHH.

Breast Cancer Resistance Protein and Multidrug Resistance Protein 2 Regulate the Disposition of Acacetin Glucuronides

PURPOSE

To determine the mechanism responsible for acacetin glucuronide transport and the bioavailability of acacetin.

METHODS

Area under the curve (AUC), clearance (CL), half-life (T1/2) and other pharmacokinetic parameters were determined by the pharmacokinetic model. The excretion of acacetin glucuronides was evaluated by the mouse intestinal perfusion model and the Caco-2 cell model.

RESULTS

In pharmacokinetic studies, the bioavailability of acacetin in FVB mice was 1.3%. Acacetin was mostly exposed as acacetin glucuronides in plasma. AUC of acacetin-7-glucuronide (Aca-7-Glu) was 2-fold and 6-fold higher in Bcrp1 (-/-) mice and Mrp2 (-/-) mice, respectively. AUC of acacetin-5-glucuronide (Aca-5-Glu) was 2-fold higher in Bcrp1 (-/-) mice. In mouse intestinal perfusion, the excretion of Aca-7-Glu was decreased by 1-fold and 2-fold in Bcrp1 (-/-) and Mrp2 (-/-) mice, respectively. In Caco-2 cells, the efflux rates of Aca-7-Glu and Aca-5-Glu were significantly decreased by breast cancer resistance protein (BCRP) inhibitor Ko143 and multidrug resistance protein 2 (MRP2) inhibitor LTC4. The use of these inhibitors markedly increased the intracellular acacetin glucuronide content.

CONCLUSIONS

BCRP and MRP2 regulated the in vivo disposition of acacetin glucuronides. The coupling of glucuronidation and efflux transport was probably the primary reason for the low bioavailability of acacetin.

Sulfonation Disposition of Acacetin: In Vitro and in Vivo

Acacetin, an important component of acacia honey, exerts extensive therapeutic effects on many cancers. However, the sulfonation disposition of acacetin has rarely been reported. Therefore, this study aimed to investigate the sulfonation disposition of acacetin systematically. The results showed that acacetin-7-sulfate was the main metabolite mediated primarily by sulfotransferases (SULT) 1A1. Dog liver S9 presented the highest formation rate of acacetin-7-sulfate. Compared with that in wild-type Friend Virus B (FVB) mice, plasma exposure of acacetin-7-sulfate decreased significantly in multidrug resistance protein 1 knockout (Mrp1^-/-) mice vut increased clearly in breast cancer resistance protein knockout (Bcrp^-/-) mice. In Caco-2 monolayers, the efflux and clearance of acacetin-7-sulfate was reduced distinctly by the BCRP inhibitor Ko143 on the apical side and by the MRP1 inhibitor MK571 on the basolateral side. In conclusion, acacetin sulfonation was mediated mostly by SULT1A1. Acacetin-7-sulfate was found to be transported mainly by BCRP and MRP1. Hence, SULT1A1, BCRP, and MRP1 are responsible for acacetin-7-sulfate exposure in vivo.

Metabolic Disposition of Luteolin Is Mediated by the Interplay of UDP-Glucuronosyltransferases and Catechol-O-Methyltransferases in Rats

Luteolin partially exerts its biologic effects via its metabolites catalyzed by UDP-glucuronosyltransferases (UGTs) and catechol-O-methyltransferases (COMTs). However, the interplay of UGTs and COMTs in mediating luteolin disposition has not been well clarified. In this study, we investigated the glucuronidation and methylation pathways of luteolin mediated by the interplay of UGTs and COMTs in vivo and in vitro. A total of nine luteolin metabolites was detected in rat plasma and bile by liquid chromatography-tandem mass spectrometry, namely, three glucuronides, two methylated metabolites, and four methylated glucuronides. Luteolin-3'-glucuronide (Lut-3'-G) exhibited the highest systemic exposure among these metabolites. Kinetics studies in rat liver S9 fractions suggested two pathways, as follows: 1) Luteolin was glucuronidated to luteolin-7-glucuronide, luteolin-4'-glucuronide, and Lut-3'-G by UGTs, and then Lut-7-G was methylated to chrysoeriol-7-glucuronide and diosmetin-7-glucuronide by COMTs. 2) Alternatively, luteolin was methylated to chrysoeriol and diosmetin by COMTs, and then chrysoeriol and diosmetin were glucuronidated by UGTs to their respective glucuronides. The methylation rate of luteolin was significantly increased by the absence of glucuronidation, whereas the glucuronidation rate was increased by the absence of methylation, but to a lesser extent. In conclusion, two pathways mediated by the interplay of UGTs and COMTs are probably involved in the metabolic disposition of luteolin. The glucuronidation and methylation of luteolin compensate for each other, although glucuronidation is the predominant pathway.

Regioselective Glucuronidation of Diosmetin and Chrysoeriol by the Interplay of Glucuronidation and Transport in UGT1A9-Overexpressing HeLa Cells

This study aimed to determine the reaction kinetics of the regioselective glucuronidation of diosmetin and chrysoeriol, two important methylated metabolites of luteolin, by human liver microsomes (HLMs) and uridine-5′-diphosphate glucuronosyltransferase (UGTs) enzymes. This study also investigated the effects of breast cancer resistance protein (BCRP) on the efflux of diosmetin and chrysoeriol glucuronides in HeLa cells overexpressing UGT1A9 (HeLa—UGT1A9). After incubation with HLMs in the presence of UDP-glucuronic acid, diosmetin and chrysoeriol gained two glucuronides each, and the OH—in each B ring of diosmetin and chrysoeriol was the preferable site for glucuronidation. Screening assays with 12 human expressed UGT enzymes and chemical-inhibition assays demonstrated that glucuronide formation was almost exclusively catalyzed by UGT1A1, UGT1A6, and UGT1A9. Importantly, in HeLa—UGT1A9, Ko143 significantly inhibited the efflux of diosmetin and chrysoeriol glucuronides and increased their intracellular levels in a dose-dependent manner. This observation suggested that BCRP-mediated excretion was the predominant pathway for diosmetin and chrysoeriol disposition. In conclusion, UGT1A1, UGT1A6, and UGT1A9 were the chief contributors to the regioselective glucuronidation of diosmetin and chrysoeriol in the liver. Moreover, cellular glucuronidation was significantly altered by inhibiting BCRP, revealing a notable interplay between glucuronidation and efflux transport. Diosmetin and chrysoeriol possibly have different effects on anti-cancer due to the difference of UGT isoforms in different cancer cells.

Optimization of the process variables of tilianin-loaded composite phospholipid liposomes based on response surface-central composite design and pharmacokinetic study

Tilianin is attracting considerable attention because of its antihypertensive, anti-atherogenic and anticonvulsive efficacy. However, tilianin has poor oral bioavailability. Thus, to improve the oral bioavailability of tilianin, composite phospholipid liposomes were adopted in this work as a novel nanoformulation. The aim was to develop and formulate tilianin composite phospholipid liposomes (TCPLs) through ethanol injection and to apply the response surface-central composite design to optimize the tilianin composite phospholipid liposome formulation. The independent variables were the amount of phospholipids (X1), amount of cholesterol (X2) and weight ratio of phospholipid to drug (X3); the depended variables were particle size (Y1) and encapsulation efficiency (EE) (Y2) of TCPLs. Results indicated that the optimum preparation conditions were as follows: phospholipid amount, 500 mg, cholesterol amount, 50mg and phospholipid/drug ratio, 25. These variables were also the major contributing variables for particle size (101.4 ± 6.1 nm), higher EE (90.28% ± 1.36%), zeta potential (-18.3 ± 2.6 mV) and PDI (0.122 ± 0.027). Subsequently, differential scanning calorimetry techniques were used to investigate the molecular interaction in TCPLs, and the in vitro drug release of tilianin and TCPLs was investigated by the second method of dissolution in the Chinese Pharmacopoeia (Edition 2015). Furthermore, pharmacokinetics in Sprague Dawley rats was evaluated using a rat jugular vein intubation tube. Results demonstrated that the Cmax of TCPLs became 5.7 times higher than that of tilianin solution and that the area under the curve of TCPLs became about 4.6-fold higher than that of tilianin solution. Overall, our results suggested that the prepared tilianin composite phospholipid liposome formulations could be used to improve the bioavailability of tilianin after oral administration.

Types, principle, and characteristics of tandem high-resolution mass spectrometry and its applications

We review the principle and functional characteristics of different types or models for THRMS and provide a brief description of its applications in medical research, food safety, and environmental protection fields.