RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Psoraleae Fructus (PF), the dried fruit of Psoralea corylifolia L., is a commonly used traditional medicine that has contributed to the treatment of orthopedic diseases for thousands of years in China. However, recent PF-related liver injury reports have drawn widespread attention regarding its potential hepatotoxicity risks. AIM OF THE STUDY: This study was aimed to evaluate the long-term efficacy and chronic toxicity of PF using a 26-week administration experiment on rats in order to simulate the clinical usage situation. MATERIALS AND METHODS: The PF aqueous extract was consecutively administrated to rats daily at dosages of 0.7, 2.0, and 5.6 g/kg (equivalent to 1-8 times the clinical doses for humans) for as long as 26 weeks. Samples were collected after 13, 26, and 32 weeks (withdrawal for 6 weeks) since the first administration. The chronic toxicity of PF was evaluated by conventional toxicological methods, and the efficacy of PF was evaluated by osteogenic effects in the natural growth process. RESULTS: In our experiments, only the H group (5.6 g/kg) for 26-week PF treatment demonstrated liver or kidney injury, which the injuries were reversible after 6 weeks of withdrawal. Notably, the PF treatment beyond 13 weeks showed significant benefits for bone growth and development in rats, with a higher benefit-risk ratio in female rats. CONCLUSIONS: PF displayed a promising benefit-risk ratio in the treatment and prevention of osteoporosis, a disease that lacks effective medicine so far. This is the first study to elucidate the benefit-risk balance associated with clinical dosage and long-term use of PF, thereby providing valuable insights for rational clinical use and risk control of PF.
Assuntos
Medicamentos de Ervas Chinesas , Fabaceae , Psoralea , Humanos , Ratos , Feminino , Animais , Frutas , Razão de Chances , Fígado , Medicamentos de Ervas Chinesas/toxicidadeRESUMO
XueBiJing is an intravenous five-herb injection used to treat sepsis in China. The study aimed to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS)- or liquid chromatography-ultraviolet (LC-UV)-based assay for quality evaluation of XueBiJing. Assay development involved identifying marker constituents to make the assay therapeutically relevant and building a reliable one-point calibrator for monitoring the various analytes in parallel. Nine marker constituents from the five herbs were selected based on XueBiJing's chemical composition, pharmacokinetics, and pharmacodynamics. A selectivity test (for "similarity of response") was developed to identify and minimize interference by non-target constituents. Then, an intercept test was developed to fulfill "linearity through zero" for each analyte (absolute ratio of intercept to C response, <2%). Using the newly developed assays, we analyzed samples from 33 batches of XueBiJing, manufactured over three years, and found small batch-to-batch variability in contents of the marker constituents (4.1%-14.8%), except for senkyunolide I (26.5%).
RESUMO
Traditional medicine has provided a basis for health care and disease treatment to Chinese people for millennia, and herbal medicines are regulated as drug products in China. Chinese herbal medicines have two features. They normally possess very complex chemical composition. This makes the identification of the constituents that are together responsible for the therapeutic action of an herbal medicine challenging, because how to select compounds from an herbal medicine for pharmacodynamic study has been a big hurdle in such identification efforts. To this end, a multi-compound pharmacokinetic approach was established to identify potentially important compounds (bioavailable at the action loci with significant exposure levels after dosing an herbal medicine) and to characterize their pharmacokinetics and disposition. Another feature of Chinese herbal medicines is their typical use as or in combination therapies. Coadministration of complex natural products and conventional synthetic drugs is prevalent worldwide, even though it remains very controversial. Natural product-drug interactions have raised wide concerns about reduced drug efficacy or safety. However, growing evidence shows that incorporating Chinese herbal medicines into synthetic drug-based therapies delivers benefits in the treatment of many multifactorial diseases. To address this issue, a drug-combination pharmacokinetic approach was established to assess drug-drug interaction potential of herbal medicines and degree of pharmacokinetic compatibility for multi-herb combination and herbal medicine-synthetic drug combination therapies. In this review we describe the methodology, techniques, requirements, and applications of multi-compound and drug-combination pharmacokinetic research on Chinese herbal medicines and to discuss further development for these two types of pharmacokinetic research.
Assuntos
Medicamentos de Ervas Chinesas , Plantas Medicinais , Humanos , Medicamentos de Ervas Chinesas/farmacologia , Plantas Medicinais/química , Medicina Tradicional Chinesa , Combinação de Medicamentos , Interações MedicamentosasRESUMO
The Chinese medicinal herb Mahuang is herbaceous stem of Ephedra sinica, E. intermedia, or E. equisetina(Family, Ephedraceae). In China, Mahuang has been used, all the way over a millennium, as a key component herb of many herbal medicines for management of epidemics of acute respiratory illness and is also used in officially recommended herbal medicines for COVID-19. Mahuang is the first-line medicinal herb for cold and wheezing and also an effective diuretic herb for edema. However, Mahuang can also exert significant adverse effects. The key to safety and effectiveness is rational and precise use of the herb. In this review article, we comprehensively summarize chemical composition of Mahuang and associated differences in pharmacognosy, pharmacodynamics and pharmacokinetics of Mahuang compounds, along with the adverse effects of Mahuang compounds and products. Based on full understanding of how Mahuang is used in Chinese traditional medicine, systematic research on Mahuang in line with contemporary standards of pharmaceutical sciences will facilitate promoting Chinese herbal medicines to become more efficient in management of epidemic illnesses, such as COVID-19. To this end, we recommend research on Mahuang of two aspects, i.e., pharmacological investigation for its multicompound-involved therapeutic effects and toxicological investigation for clinical manifestation of the adverse effects, chemicals responsible for the adverse effects, and conditions for safe use of the herb and the herb-containing medicines.
Assuntos
Tratamento Farmacológico da COVID-19 , Medicamentos de Ervas Chinesas , Ephedra sinica , Ephedra , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacologia , Ephedra sinica/química , Efedrina/química , Humanos , PlantasRESUMO
Phenolic acids are cardiovascular constituents (originating from the Chinese medicinal herb Salvia miltiorrhiza root/Danshen) of DanHong and many other Danshen-containing injections. Our earlier pharmacokinetic investigation of DanHong suggested that hepatic and/or renal uptake of the Danshen compounds was the crucial steps in their systemic elimination. This investigation was designed to survey the molecular basis underlying hepatobiliary and renal excretion of the Danshen compounds, i.e., protocatechuic acid, tanshinol, rosmarinic acid, salvianolic acid D, salvianolic acid A, lithospermic acid, and salvianolic acid B. A large battery of human hepatic and renal transporters were screened for transporting the Danshen compounds and then characterized for the uptake kinetics and also compared with associated rat transporters. The samples were analyzed by liquid chromatography/mass spectrometry. Because the Danshen phenolic acids are of poor or fairly good membrane permeability, their elimination via the liver or kidneys necessitates transporter-mediated hepatic or renal uptake from blood. Several human transporters were found to mediate hepatic and/or renal uptake of the Danshen compounds in a compound-molecular-mass-related manner. Lithospermic acid and salvianolic acid B (both >500 Da) underwent systemic elimination, initiated by organic anion-transporting polypeptide (OATP)1B1/OATP1B3-mediated hepatic uptake. Rosmarinic acid and salvianolic acids D (350-450 Da) underwent systemic elimination, initiated by OATP1B1/OATP1B3/organic anion transporter (OAT)2-mediated hepatic uptake and by OAT1/OAT2-mediated renal uptake. Protocatechuic acid and tanshinol (both <200 Da) underwent systemic elimination, initiated by OAT1/OAT2-mediated renal uptake and OAT2-mediated hepatic uptake. A similar scenario was observed with the rat orthologs. The investigation findings advance our understanding of the disposition of the Danshen phenolic acids and could facilitate pharmacokinetic research on other Danshen-containing injections.
RESUMO
XueBiJing is an intravenous five-herb injection used to treat sepsis in China.The study aimed to develop a liquid chromatography-tandem mass spectrometry(LC-MS/MS)-or liquid chromatography-ultraviolet(LC-UV)-based assay for quality evaluation of XueBiJing.Assay development involved identifying marker constituents to make the assay therapeutically relevant and building a reliable one-point cali-brator for monitoring the various analytes in parallel.Nine marker constituents from the five herbs were selected based on XueBiJing's chemical composition,pharmacokinetics,and pharmacodynamics.A selectivity test(for"similarity of response")was developed to identify and minimize interference by non-target constituents.Then,an intercept test was developed to fulfill"linearity through zero"for each analyte(absolute ratio of intercept to C response,<2%).Using the newly developed assays,we analyzed samples from 33 batches of XueBiJing,manufactured over three years,and found small batch-to-batch variability in contents of the marker constituents(4.1%-14.8%),except for senkyunolide I(26.5%).
RESUMO
LianhuaQingwen capsule, prepared from an herbal combination, is officially recommended as treatment for COVID-19 in China. Of the serial pharmacokinetic investigations we designed to facilitate identifying LianhuaQingwen compounds that are likely to be therapeutically important, the current investigation focused on the component Glycyrrhiza uralensis roots (Gancao). Besides its function in COVID-19 treatment, Gancao is able to induce pseudoaldosteronism by inhibiting renal 11ß-HSD2. Systemic and colon-luminal exposure to Gancao compounds were characterized in volunteers receiving LianhuaQingwen and by in vitro metabolism studies. Access of Gancao compounds to 11ß-HSD2 was characterized using human/rat, in vitro transport, and plasma protein binding studies, while 11ß-HSD2 inhibition was assessed using human kidney microsomes. LianhuaQingwen contained a total of 41 Gancao constituents (0.01-8.56 µmol/day). Although glycyrrhizin (1), licorice saponin G2 (2), and liquiritin/liquiritin apioside (21/22) were the major Gancao constituents in LianhuaQingwen, their poor intestinal absorption and access to colonic microbiota resulted in significant levels of their respective deglycosylated metabolites glycyrrhetic acid (8), 24-hydroxyglycyrrhetic acid (M2D; a new Gancao metabolite), and liquiritigenin (27) in human plasma and feces after dosing. These circulating metabolites were glucuronized/sulfated in the liver and then excreted into bile. Hepatic oxidation of 8 also yielded M2D. Circulating 8 and M2D, having good membrane permeability, could access (via passive tubular reabsorption) and inhibit renal 11ß-HSD2. Collectively, 1 and 2 were metabolically activated to the pseudoaldosterogenic compounds 8 and M2D. This investigation, together with such investigations of other components, has implications for precisely defining therapeutic benefit of LianhuaQingwen and conditions for its safe use.
Assuntos
Antivirais/farmacocinética , Tratamento Farmacológico da COVID-19 , Medicamentos de Ervas Chinesas/farmacocinética , Compostos Fitoquímicos/farmacocinética , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/antagonistas & inibidores , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/metabolismo , Administração Oral , Animais , Antivirais/administração & dosagem , Antivirais/efeitos adversos , Disponibilidade Biológica , Biotransformação , Cápsulas , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/efeitos adversos , Feminino , Glycyrrhiza/efeitos adversos , Células HEK293 , Humanos , Síndrome de Liddle/induzido quimicamente , Síndrome de Liddle/enzimologia , Masculino , Segurança do Paciente , Compostos Fitoquímicos/administração & dosagem , Compostos Fitoquímicos/efeitos adversos , Ratos Sprague-Dawley , Medição de RiscoRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Many bioactive constituents of Chinese herbal medicines have poor oral bioavailability. Besides oral administration, herbal medicines in China are also prepared for parenteral administration. Unlike for intravenous route, little is known about the intramuscular pharmacokinetics of herbal compounds. To facilitate rational use of herbal medicine, it is important to better understand such intramuscular pharmacokinetics. AIM OF THE STUDY: Bioactive constituents of XueShuanTong (a lyophilized extract of Panax notoginseng roots, extensively used in treatment of ischemic heart and cerebrovascular diseases) predominantly comprise ginsenosides Rb1 and Rd of 20(S)-protopanaxadiol-type and ginsenosides Rg1, and Re, and notoginsenoside R1 of 20(S)-protopanaxatriol-type; these saponins are poorly absorbed from the gastrointestinal tract. This study aimed to compare intramuscular and intravenous pharmacokinetics of these ginsenosides after dosing XueShuanTong. METHODS: Pharmacokinetics of ginsenosides was assessed in human volunteers receiving an intramuscular injection or 1.5-h intravenous infusion of XueShuanTong, both at 150 mg/person, and the plasma and urine samples were analyzed by liquid chromatography/mass spectrometry. RESULTS: Like after intravenous administration, the unchanged saponins were the major circulating forms after intramuscular administration, while their metabolites were poorly detected. These ginsenosides exhibited intramuscular bioavailability of 100%-112%, relative to the respective intravenous data. Similar to that after intravenous infusion, the 20(S)-protopanaxadiol-type ginsenosides after the intramuscular injection exhibited notably longer terminal half-lives (46-106 h) than the 20(S)-protopanaxatriol-type ginsenosides (1.1-1.4 h). CONCLUSIONS: Intramuscular route might be an effective alternative to intravenous route for XueShuanTong, from the pharmacokinetic perspective.
Assuntos
Medicamentos de Ervas Chinesas/farmacocinética , Ginsenosídeos/metabolismo , Administração Intravenosa , Adulto , Medicamentos de Ervas Chinesas/administração & dosagem , Liofilização , Humanos , Injeções Intramusculares , Masculino , Panax notoginseng , Raízes de Plantas , Adulto JovemRESUMO
XueShuanTong, a lyophilized extract of Panax notoginseng roots (Sanqi) for intravenous administration, is extensively used as add-on therapy in the treatment of ischemic heart and cerebrovascular diseases and comprises therapeutically active ginsenosides. Potential for XueShuanTong-drug interactions was determined; the investigation focused on cytochrome P450 (CYP)3A induction and organic anion-transporting polypeptide (OATP)1B inhibition. Ginsenosides considerably bioavailable for drug interactions were identified by dosing XueShuanTong in human subjects and their interaction-related pharmacokinetics were determined. The CYP3A induction potential was determined by repeatedly dosing XueShuanTong for 15 days in human subjects and by treating cryopreserved human hepatocytes with circulating ginsenosides; midazolam served as a probe substrate. Joint inhibition of OATP1B by XueShuanTong ginsenosides was assessed in vitro, and the data were processed using the Chou-Talalay method. Samples were analyzed by liquid chromatography/mass spectrometry. Ginsenosides Rb1, Rd, and Rg1 and notoginsenoside R1 were the major circulating XueShuanTong compounds; their interaction-related pharmacokinetics comprised compound dose-dependent levels of systemic exposure and, for ginsenosides Rb1 and Rd, long terminal half-lives (32â57 and 58â307 h, respectively) and low unbound fractions in plasma (0.8%â2.9% and 0.4%â3.0%, respectively). Dosing XueShuanTong did not induce CYP3A. Based on the pharmacokinetics and inhibitory potency of the ginsenosides, XueShuanTong was predicted to have high potential for OATP1B3-mediated drug interactions (attributed chiefly to ginsenoside Rb1) suggesting the need for further model-based determination of the interaction potential for XueShuanTong and, if necessary, a clinical drug interaction study. Increased awareness of ginsenosides' pharmacokinetics and XueShuanTong-drug interaction potential will help ensure the safe use of XueShuanTong and coadministered synthetic drugs.
Assuntos
Citocromo P-450 CYP3A/biossíntese , Medicamentos de Ervas Chinesas/farmacocinética , Ginsenosídeos/farmacocinética , Transportador 1 de Ânion Orgânico Específico do Fígado/antagonistas & inibidores , Raízes de Plantas/química , Administração Intravenosa , Adulto , Cromatografia Líquida , Composição de Medicamentos , Interações Medicamentosas , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/química , Feminino , Ginsenosídeos/administração & dosagem , Ginsenosídeos/química , Voluntários Saudáveis , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Transportador 1 de Ânion Orgânico Específico do Fígado/metabolismo , Masculino , Espectrometria de Massas , Conformação Molecular , Adulto JovemRESUMO
ShenMai, an intravenous injection prepared from steamed Panax ginseng roots (Hongshen) and Ophiopogon japonicus roots (Maidong), is used as an add-on therapy for coronary artery disease and cancer; saponins are its bioactive constituents. Since many saponins inhibit human organic anion-transporting polypeptides (OATP)1B, this investigation determined the inhibition potencies of circulating ShenMai saponins on the transporters and the joint potential of these compounds for ShenMai-drug interaction. Circulating saponins and their pharmacokinetics were characterized in rats receiving a 30-min infusion of ShenMai at 10 mL/kg. Inhibition of human OATP1B1/1B3 and rat Oatp1b2 by the individual saponins was investigated in vitro; the compounds' joint inhibition was also assessed in vitro and the data was processed using the Chou-Talalay method. Plasma protein binding was assessed by equilibrium dialysis. Altogether, 49 saponins in ShenMai were characterized and graded into: 10-100 µmol/day (compound doses from ShenMai; 7 compounds), 1-10 µmol/day (17 compounds), and <1 µmol/day (25 compounds, including Maidong ophiopogonins). After dosing, circulating saponins were protopanaxadiol-type ginsenosides Rb1, Rb2, Rc, Rd, Ra1, Rg3, Ra2, and Ra3, protopanaxatriol-type ginsenosides Rg1, Re, Rg2, and Rf, and ginsenoside Ro. The protopanaxadiol-type ginsenosides exhibited maximum plasma concentrations of 2.1-46.6 µmol/L, plasma unbound fractions of 0.4-1.0% and terminal half-lives of 15.6-28.5 h (ginsenoside Rg3, 1.9 h), while the other ginsenosides exhibited 0.1-7.7 µmol/L, 20.8-99.2%, and 0.2-0.5 h, respectively. The protopanaxadiol-type ginsenosides, ginsenosides without any sugar attachment at C-20 (except ginsenoside Rf), and ginsenoside Ro inhibited OATP1B3 more potently (IC50, 0.2-3.5 µmol/L) than the other ginsenosides (≥22.6 µmol/L). Inhibition of OATP1B1 by ginsenosides was less potent than OATP1B3 inhibition. Ginsenosides Rb1, Rb2, Rc, Rd, Ro, Ra1, Re, and Rg2 likely contribute the major part of OATP1B3-mediated ShenMai-drug interaction potential, in an additive and time-related manner.
Assuntos
Medicamentos de Ervas Chinesas/farmacocinética , Ginsenosídeos/farmacocinética , Transportador 1 de Ânion Orgânico Específico do Fígado/antagonistas & inibidores , Membro 1B3 da Família de Transportadores de Ânion Orgânico Carreador de Soluto/antagonistas & inibidores , Administração Intravenosa , Animais , Combinação de Medicamentos , Interações Medicamentosas , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/metabolismo , Ginsenosídeos/administração & dosagem , Ginsenosídeos/sangue , Ginsenosídeos/metabolismo , Humanos , Transportador 1 de Ânion Orgânico Específico do Fígado/metabolismo , Masculino , Ophiopogon/química , Panax/química , Ligação Proteica , Ratos Sprague-Dawley , Membro 1B3 da Família de Transportadores de Ânion Orgânico Carreador de Soluto/metabolismoRESUMO
Terpene lactones are a class of bioactive constituents of standardized preparations of Ginkgo biloba leaf extract, extensively used as add-on therapies in patients with ischemic cardiovascular and cerebrovascular diseases. This investigation evaluated human pharmacokinetics of ginkgo terpene lactones and impact of their carboxylation in blood. Human subjects received oral YinXing-TongZhi tablet or intravenous ShuXueNing, two standardized ginkgo preparations. Their plasma protein-binding and platelet-activating factor antagonistic activity were assessed in vitro. Their carboxylation was assessed in phosphate-buffered saline (pH 7.4) and in human plasma. After dosing YinXing-TongZhi tablet, ginkgolides A and B and bilobalide exhibited significantly higher systemic exposure levels than ginkgolides C and J; after dosing ShuXueNing, ginkgolides A, B, C, and J exhibited high exposure levels. The compounds' unbound fractions in plasma were 45-92%. Apparent oral bioavailability of ginkgolides A and B was mostly >100%, while that of ginkgolides C and J was 6-15%. Bilobalide's bioavailability was probably high but lower than that of ginkgolides A/B. Terminal half-lives of ginkgolides A, B, and C (4-7 h) after dosing ShuXueNing were shorter than their respective values (6-13 h) after dosing YinXing-TongZhi tablet. Half-life of bilobalide after dosing the tablet was around 5 h. Terpene lactones were roughly evenly distributed in various body fluids and tissues; glomerular-filtration-based renal excretion was the predominant elimination route for the ginkgolides and a major route for bilobalide. Terpene lactones circulated as trilactones and monocarboxylates. Carboxylation reduced platelet-activating factor antagonistic activity of ginkgolides A, B, and C. Ginkgolide J, bilobalide, and ginkgo flavonoids exhibited no such bioactivity. Collectively, differences in terpene lactones' exposure between the two preparations and influence of their carboxylation in blood should be considered in investigating the relative contributions of terpene lactones to ginkgo preparations' therapeutic effects. The results here will inform rational clinical use of ginkgo preparations.
Assuntos
Medicamentos de Ervas Chinesas/farmacocinética , Ginkgolídeos/farmacocinética , Lactonas/farmacocinética , Fator de Ativação de Plaquetas/antagonistas & inibidores , Adulto , Animais , Fenômenos Bioquímicos/efeitos dos fármacos , Medicamentos de Ervas Chinesas/química , Feminino , Ginkgo biloba/química , Ginkgolídeos/sangue , Ginkgolídeos/química , Ginkgolídeos/urina , Células HEK293 , Humanos , Lactonas/sangue , Lactonas/química , Lactonas/urina , Masculino , Coelhos , Adulto JovemRESUMO
AIM: Monoterpene glycosides derived from Paeonia lactiflora roots (Chishao) are believed to be pharmacologically important for the antiseptic herbal injection XueBiJing. This study was designed to characterize the pharmacokinetics and disposition of monoterpene glycosides. METHODS: Systemic exposure to Chishao monoterpene glycosides was assessed in human subjects receiving an intravenous infusion and multiple infusions of XueBiJing injection, followed by assessment of the pharmacokinetics of the major circulating compounds. Supportive rat studies were also performed. Membrane permeability and plasma-protein binding were assessed in vitro. RESULTS: A total of 18 monoterpene glycosides were detected in XueBiJing injection (content levels, 0.001-2.47 mmol/L), and paeoniflorin accounted for 85.5% of the total dose of monoterpene glycosides detected. In human subjects, unchanged paeoniflorin exhibited considerable levels of systemic exposure with elimination half-lives of 1.2-1.3 h; no significant metabolite was detected. Oxypaeoniflorin and albiflorin exhibited low exposure levels, and the remaining minor monoterpene glycosides were negligible or undetected. Glomerular-filtration-based renal excretion was the major elimination pathway of paeoniflorin, which was poorly bound to plasma protein. In rats, the systemic exposure level of paeoniflorin increased proportionally as the dose was increased. Rat lung, heart, and liver exposure levels of paeoniflorin were lower than the plasma level, with the exception of the kidney level, which was 4.3-fold greater than the plasma level; brain penetration was limited by the poor membrane permeability. CONCLUSION: Due to its significant systemic exposure and appropriate pharmacokinetic profile, as well as previously reported antiseptic properties, paeoniflorin is a promising XueBiJing constituent of therapeutic importance.
Assuntos
Medicamentos de Ervas Chinesas/farmacocinética , Glucosídeos/farmacocinética , Glicosídeos/farmacocinética , Monoterpenos/farmacocinética , Paeonia/química , Adulto , Animais , Proteínas Sanguíneas/metabolismo , Células CACO-2 , Permeabilidade da Membrana Celular , Feminino , Glucosídeos/sangue , Glucosídeos/urina , Glicosídeos/sangue , Glicosídeos/urina , Humanos , Masculino , Monoterpenos/sangue , Monoterpenos/urina , Raízes de Plantas/química , Ligação Proteica , Ratos Sprague-Dawley , Adulto JovemRESUMO
AIM: Tanshinol is an important catechol in the antianginal herb Salvia miltiorrhiza roots (Danshen). This study aimed to characterize tanshinol methylation. METHODS: Metabolites of tanshinol were analyzed by liquid chromatography/mass spectrometry. Metabolism was assessed in vitro with rat and human enzymes. The major metabolites were synthesized for studying their interactions with drug metabolizing enzymes and transporters and their vasodilatory properties. Dose-related tanshinol methylation and its influences on tanshinol pharmacokinetics were also studied in rats. RESULTS: Methylation, preferentially in the 3-hydroxyl group, was the major metabolic pathway of tanshinol. In rats, tanshinol also underwent considerable 3-O-sulfation, which appeared to be poor in human liver. These metabolites were mainly eliminated via renal excretion, which involved tubular secretion mainly by organic anion transporter (OAT) 1. The methylated metabolites had no vasodilatory activity. Entacapone-impaired methylation did not considerably increase systemic exposure to tanshinol in rats. The saturation of tanshinol methylation in rat liver could be predicted from the Michaelis constant of tanshinol for catechol-O-methyltransferase (COMT). Tanshinol had low affinity for human COMT and OATs; its methylated metabolites also had low affinity for the transporters. Tanshinol and its major human metabolite (3-O-methyltanshinol) exhibited negligible inhibitory activities against human cytochrome P450 enzymes, organic anion transporting polypeptides 1B1/1B3, multidrug resistance protein 1, multidrug resistance-associated protein 2, and breast cancer resistance protein. CONCLUSION: Tanshinol is mainly metabolized via methylation. Tanshinol and its major human metabolite have low potential for pharmacokinetic interactions with synthetic antianginal agents. This study will help define the risk of hyperhomocysteinemia related to tanshinol methylation.
Assuntos
Ácidos Cafeicos/farmacocinética , Fármacos Cardiovasculares/farmacocinética , Medicamentos de Ervas Chinesas/farmacocinética , Fígado/enzimologia , Salvia miltiorrhiza/química , Administração Oral , Animais , Biotransformação , Ácidos Cafeicos/administração & dosagem , Ácidos Cafeicos/isolamento & purificação , Ácidos Cafeicos/toxicidade , Fármacos Cardiovasculares/administração & dosagem , Fármacos Cardiovasculares/isolamento & purificação , Fármacos Cardiovasculares/toxicidade , Catecol O-Metiltransferase/metabolismo , Cromatografia Líquida , Sistema Enzimático do Citocromo P-450/metabolismo , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/isolamento & purificação , Medicamentos de Ervas Chinesas/toxicidade , Interações Ervas-Drogas , Humanos , Injeções Intravenosas , Túbulos Renais/metabolismo , Masculino , Espectrometria de Massas , Proteínas de Membrana Transportadoras/metabolismo , Metilação , Microssomos Hepáticos/enzimologia , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Fitoterapia , Raízes de Plantas , Plantas Medicinais , Ratos Sprague-Dawley , Eliminação Renal , Sulfatos/metabolismoRESUMO
AIM: To investigate the limiting factors for oral bioavailability of flavonoids derived from the Chinese herbal remedy Xiaochaihu-tang. The investigational flavonoids included baicalin, wogonoside, oroxylin-A 7-O-beta-Dglucopyranosiduronide, liquiritin, liquiritin apioside, isoliquiritin, and isoliquiritin apioside, as well as their aglycones baicalein, wogonin, oroxylin-A, liquiritigenin, and isoliquiritigenin. METHODS: Caco-2 cell monolayers were used and the apparent permeability both in apical to basolateral and basolateral to apical directions was measured for each investigational compound. Meanwhile, chemoinformatics was carried out to provide insight into the mechanism governing the permeability. In addition, carrier-mediated transport with or without inhibitors, as well as the metabolism by conjugation, was also examined with Caco- 2 cell monolayers for the flavonoids. RESULTS: The investigational flavonoid aglycones exhibited favorable membrane permeability, but efficient glucuronidation and/or sulfation by the enterocytes may limit their bioavailability. For the flavonoid glycosides, their poor membrane permeability was found to be caused by high hydrogen-bonding potential. Among the glycosides, oroxylin-A 7-O-beta- D-glucopyranosiduronide, isoliquiritin, and isoliquiritin apioside were transported under the mediation of the efflux transporters multidrug resistance-associated protein and/or P-glycoprotein. CONCLUSION: The limiting factors of oral bioavailability for the flavonoids derived from Xiaochaihu-tang appeared to include poor membrane permeability, significant efflux, and efficient intestinal metabolism by conjugation.