Min Sun Choi

Interactions between herbs and antidiabetics: an overview of the mechanisms, evidence, importance, and management.

Complementary and alternative therapies are quickly gaining importance because they are perceived to be free of side effects due to their natural origin. However, herbal remedies are complex mixtures of bioactive entities, which may interact with prescription drugs through pharmacokinetic or pharmacodynamic mechanisms and sometimes result in life-threatening consequences. In particular, diabetes patients are often treated with multiple medications due to different comorbidities, and such patients use antidiabetic medications for their entire lives; thus, it is important to make the public aware of herb interactions with antidiabetic drugs. In this paper, we summarize the reports available on the interaction of herbal remedies with oral hypoglycemic agents and describe mechanisms, preclinical or clinical evidence, importance, and management strategies.

Development of a hydrophilic interaction liquid chromatography–tandem mass spectrometric method for the determination of kinsenoside, an antihyperlipidemic candidate, in rat plasma and its application to pharmacokinetic studies

Kinsenoside is a major bioactive constituent isolated from Anoectochilus formosanus and is investigated as an antihyperlipidemic candidate. In this study, a rapid, sensitive, and reliable bioanalytical method was developed for the determination of kinsenoside in rat plasma using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). The plasma sample was pretreated with 1% acetic acid, followed by protein precipitation with acetonitrile:methanol (70:30). Chromatographic separation was performed on a HILIC silica column (2.1mm×100mm, 3μm). The mobile phases consisted of 0.1% acetic acid in distilled water (solvent A) and 0.1% acetic acid in acetonitrile (solvent B). A gradient program was used at a flow rate of 0.2mL/min. For mass spectrometric detection, the multiple reaction monitoring mode was used; the MRM transitions were m/z 265.2→m/z 102.9 for kinsenoside and m/z 163.3→m/z 132.1 for the internal standard (IS) nicotine in the positive ionization mode. A calibration curve was constructed in the range of 2-500ng/mL. The intra- and interday precision and accuracy were within 5%. The HILIC-MS/MS method was specific, accurate, and reproducible and was successfully applied in a pharmacokinetic study of kinsenoside in rats.

Evaluation of Metabolic Stability of Kinsenoside, an Antidiabetic Candidate, in Rat and Human Liver Microsomes

Kinsenoside is a principle bioactive compound of Anoectochilus formosanus. It exhibits various pharmacological effects such as antihyperglycemic, antioxidant, anti-inflammatory, immunostimulating, and hepatoprotective activities and has recently been developed as an antidiabetic drug candidate. In this study, as part of an in vitro pharmacokinetic study, the stability of kinsenoside in rat and human liver microsomes was evaluated. Kinsenoside was found to have good metabolic stability in both rat and human liver microsomes. These results will provide useful information for further in vivo pharmacokinetic and metabolism studies.

Evaluation of herb–drug interactions of Hovenia dulcis fruit extracts

Background: Hovenia dulcis (Rhamnaceae) fruits are popularly used as herbal medicines or dietary supplements in Asian countries due to functions such as liver protection and detoxification from alcohol poisoning. Accordingly, it is very likely for dietary supplemental products, including H. dulcis fruit extracts, to be taken with prescription drugs. Objective: In this study, possible food–drug interactions involving H. dulcis fruit extracts were evaluated based on the inhibition of cytochrome P450 (CYP) enzyme activity. Material and Methods: The water extract of H. dulcis fruit extracts was incubated in human liver microsomes with CYP-specific substrates. The formation of the CYP-specific metabolites was measured using liquid chromatography-tandem mass spectrometry. Results: H. dulcis fruit extracts showed negligible effects on seven CYP isozyme activities at all concentrations tested. Conclusion: This result suggests that H. dulcis fruit extracts may have minimal pharmacokinetic interactions with coadministered drugs through the modulation of CYP enzymes. Abbreviations Used: CYP: cytochrome P450 enzymes, HPLC: High performance liquid chromatography, LC-MS/MS : liquid chromatography-tandem mass spectrometry, MRM: multiple-reaction monitoring

An ultra-high-performance liquid chromatography-tandem mass spectrometric method for the determination of hederacoside C, a drug candidate for respiratory disorder, in rat plasma.

Hederacoside C is a principal bioactive pharmaceutical ingredient of Hedera helix leaf extracts. H. helix extracts have long been used in folk medicine for the treatment of respiratory disorders. Currently, hederacoside C is investigated as a promising candidate for the treatment of respiratory diseases. In this study, an accurate, sensitive, rapid, and reliable bioanalytical method was developed for the determination of hederacoside C in rat plasma using ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). For sample preparation, plasma proteins were precipitated with 0.1% acetic acid in acetonitrile. Waters UPLC BEH C18 (2.1mm I.D.×100mm, 1.7μm) column was used for chromatographic separation. A gradient elution of mobile phases consisting of 0.02% acetic acid in distilled water (solvent A) and 0.02% acetic acid in acetonitrile (solvent B) was used at a flow rate of 0.3mL/min. The multiple reaction monitoring (MRM) mode was used for mass spectrometric detection; the MRM transitions were m/z 1219.7→m/z 469.2 for hederacoside C and m/z 1108.3→m/z 221.2 for ginsenoside Rb1 (internal standard) in the negative ionization mode. A calibration curve was constructed in the range of 10-1000ng/mL. The intra- and inter-day precision and accuracy were within 5%. The developed UPLC-MS/MS method was successfully applied in a pharmacokinetic study of hederacoside C in rats. Hederacoside C was quickly but inadequately absorbed from the gastrointestinal tract of rats resulting in extremely low bioavailability and relatively slow clearance.

Stress-induced changes of neurosteroid profiles in rat brain and plasma under immobilized condition

&NA; In this study, various neurosteroids in brain and plasma were simultaneously determined using liquid chromatography‐tandem mass spectrometry and their profile changes in a stress‐induced rats were investigated. The investigated neurosteroids are as follows: progesterone (P4), 5&agr;‐dihydroprogesterone (5&agr;‐DHP), 5&bgr;‐dihydroprogesterone, estrone, androstenedione (AE), cortisol, cortisone, corticosterone (CORT), dehydroepiandrosterone (DHEA), pregnanolone (3&agr;,5&bgr;‐THP), allopregnanolone (ALLO), 11‐deoxycorticosterone (DOC), 11‐deoxycortisol, pregnenolone (PREG), and 5&agr;/5&bgr;‐tetrahydrodeoxycorticosterone (5&agr;/5&bgr;‐THDOC). Brain and plasma samples were processed using solid‐phase extraction with methanol and acetic acid (99:1), and derivatized with a hydroxylamine reagent. Separation was achieved within 13 min at a flow rate of 0.4 mL/min with a C18 column (3.0 × 50 mm, 2.7 &mgr;m). The triple quadrupole mass spectrometer was operated in the positive electrospray ionization mode. Using this method, the neurosteroid level variation was quantitated and investigated in the brain and plasma upon immobilization stress in rats. As a result, AE, CORT, DOC, P4, 5&agr;‐DHP, 5&agr;/5&bgr;‐THDOC, DHEA, 3&agr;,5&bgr;‐THP, ALLO, and PREG levels were significantly altered in both the brain and plasma samples when stress was induced. These findings demonstrated that stress leads to the alteration of the GABAergic neurosteroid profile. The present results will be helpful for furthering an understanding of the role of neurosteroids in stressed conditions. Graphical abstract Figure. No caption available. HighlightsNeurosteroid levels in rat brain and plasma were determined in the stress‐induced rats.The neurosteroid quantitation was performed using LC–MS/MS following derivatization.AE, CORT, DOC, P4, 5&agr;‐DHP, 5&bgr;‐THDOC, DHEA, 3&agr;,5&bgr;‐THP, ALLO, and PREG levels were significantly altered.

Determination of eurycomanone in rat plasma using hydrophilic interaction liquid chromatography-tandem mass spectrometry for pharmacokinetic study.

In this study, a rapid, sensitive, and reliable hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method for the determination of eurycomanone in rat plasma was developed and validated. Plasma samples were pretreated with a protein precipitation method and quercitrin was used as an internal standard (IS). A HILIC silica column (2.1 × 100 mm, 3 μm) was used for hydrophilic-based chromatographic separation, using the mobile phase of 0.1% formic acid with acetonitrile in gradient elution at a flow rate of 0.25 mL/min. Precursor-product ion pairs for multiple-reaction monitoring were m/z 409.1 → 391.0 for eurycomanone and m/z 449.1 → 303.0 for IS. The linear range was 2-120 ng/mL. The intra- and inter-day accuracies were between 95.5 and 103.4% with a precision of <4.2%. The developed method was successfully applied to the pharmacokinetic analysis of eurycomanone in rat plasma after oral dosing with pure compound and E. longifolia extract. The Cmax and AUC0-t , respectively, were 40.43 ± 16.08 ng/mL and 161.09 ± 37.63 ng h/mL for 10 mg/kg eurycomanone, and 9.90 ± 3.97 ng/mL and 37.15 ± 6.80 ng h/mL for E. longifolia extract (2 mg/kg as eurycomanone). The pharmacokinetic results were comparable with each other, based on the dose as eurycomanone.

Tentative identification of in vitro metabolites of 5-APDB, a synthetic benzofuran, by LC-Q/TOF-MS

5-(2-Aminopropyl)-2,3-dihydrobenzofuran (5-APDB) is a designer drug of phenethylamine and amphetamine class. In this study, the in vitro metabolism of 5-APDB was investigated in rat and human liver microsomes and human hepatocytes to characterize its metabolites. 5-APDB was incubated with microsomes or hepatocytes, and the reaction mixture was analyzed using liquid chromatography-quadrupole time-of-flight with tandem mass spectrometry (LC-Q/TOF-MS). 5-APDB was metabolized to yield three metabolites (M1, M2 and M3). These metabolites were structurally characterized on the basis of accurate mass analysis and MS/MS fragmentation patterns. Metabolite M1 and M2 were identified as hydroxylated metabolites in the benzofuran moiety; M3 was a reduced metabolite which may be generated from M1 or M2 via dehydration. These results provide evidence for the in vivo 5-APDB metabolism, and would be forensically useful for the detection of 5-APDB and its metabolites in biological samples.

The role of gut microbiota in the pharmacokinetics of antihypertensive drugs

&NA; The intestine is one of the most important sites for the metabolism of several xenobiotic compounds. In addition to intestinal drug‐metabolizing enzymes and drug transporters, gut microbial enzymes modulate the biotransformation of orally administered drugs in the gastrointestinal tract. Antihypertensive drugs such as amlodipine and nifedipine could be metabolized by gut microbial enzymes, which may influence drug absorption, leading to changes in pharmacological potency of the drug and eventual failure of the appropriate blood pressure control or unexpected side effects. This may suggest that there are additional mechanisms that can alter the therapeutic efficacy of antihypertensive drugs, especially in certain pathological conditions of the gastrointestinal tract or with concomitant use of substances such as antibiotics and probiotics that might alter the gut microbial composition. This review describes the metabolism of antihypertensive drugs by hepatic and intestinal microbial enzymes in an attempt to understand the potential effects of gut microbiota on their pharmacokinetics. Graphical abstract Figure. No caption available.

Effect of probiotics on pharmacokinetics of orally administered acetaminophen in mice

Orally administered probiotics change gut microbiota composition and enzyme activities. Thus, coadministration of probiotics with drugs may lead to changes in the pharmacokinetic parameters of the drugs. In this study, we investigated the pharmacokinetics of acetaminophen in mice treated with probiotics. Oral administration of probiotics changed the gut microbiota composition in the mice. Of these probiotics, Lactobacillus reuteri K8 increased the numbers of clostridia, bifidobacteria, and enterococci, and Lactobacillus rhamnosus K9 decreased the number of bifidobacteria, determined by culturing in selective media. Next, we performed a pharmacokinetic study of acetaminophen in mice orally treated with K8 and K9 for 3 days. Treatment with K8 reduced the area under the curve (AUC) of orally administered acetaminophen to 68.4% compared with normal control mice, whereas K9 did not affect the AUC of acetaminophen. Oral administration to mice of K8, which degraded acetaminophen, increased the degradation of acetaminophen by gut microbiota, whereas K9 treatment did not affect it. Treatment with K8 increased the number of L. reuteri adhered in the upper small intestine, whereas the number of L. rhamnosus was not affected by treatment with K8 or K9. K8 increased the number of cyanobacteria, whereas K9 increased the number of deferribacteres. These results suggest that the intake of probiotics may make the absorption of orally administered drugs fluctuate through the disturbance of gut microbiota-mediated drug metabolism and that the subsequent impact on microbiota metabolism could result in altered systemic concentrations of the intact drug.