Expanding potential targets of herbal chemicals by node2vec based on herb-drug interactions

BACKGROUND

The identification of chemical-target interaction is key to pharmaceutical research and development, but the unclear materials basis and complex mechanisms of traditional medicine (TM) make it difficult, especially for low-content chemicals which are hard to test in experiments. In this research, we aim to apply the node2vec algorithm in the context of drug-herb interactions for expanding potential targets and taking advantage of molecular docking and experiments for verification.

METHODS

Regarding the widely reported risks between cardiovascular drugs and herbs, Salvia miltiorrhiza (Danshen, DS) and Ligusticum chuanxiong (Chuanxiong, CX), which are widely used in the treatment of cardiovascular disease (CVD), and approved drugs for CVD form the new dataset as an example. Three data groups DS-drug, CX-drug, and DS-CX-drug were applied to serve as the context of drug-herb interactions for link prediction. Three types of datasets were set under three groups, containing information from chemical-target connection (CTC), chemical-chemical connection (CCC) and protein-protein interaction (PPI) in increasing steps. Five algorithms, including node2vec, were applied as comparisons. Molecular docking and pharmacological experiments were used for verification.

RESULTS

Node2vec represented the best performance with average AUROC and AP values of 0.91 on the datasets "CTC, CCC, PPI". Targets of 32 herbal chemicals were identified within 43 predicted edges of herbal chemicals and drug targets. Among them, 11 potential chemical-drug target interactions showed better binding affinity by molecular docking. Further pharmacological experiments indicated caffeic acid increased the thermal stability of the protein GGT1 and ligustilide and low-content chemical neocryptotanshinone induced mRNA change of FGF2 and MTNR1A, respectively.

CONCLUSIONS

The analytical framework and methods established in the study provide an important reference for researchers in discovering herb-drug interactions, alerting clinical risks, and understanding complex mechanisms of TM.

Flecainide toxicity associated with the use of goji berries: a case report

Background

Goji berries (GB), usually marketed as a 'superfruit', are a widely used herbal supplement. As with other herbal remedies, the use of GB might be associated with herb-drug interactions, increasing plasma levels of other drugs and causing adverse events. Here, we present the case of a patient that developed flecainide toxicity secondary to an herb-drug interaction, associated with the use of GB to prevent COVID-19.

Case summary

A 75-year-old female presented to the emergency department with fainting. She was taking flecainide for the treatment of atrial extrasystoles diagnosed 2 years previously, and she was using a tea of GB for the prevention of COVID-19. The admission electrocardiogram showed a wide complex polymorphic tachycardia that was considered and treated as flecainide toxicity. The patient had a favourable evolution and was discharged 48 h after admission.

Discussion

Flecainide toxicity is uncommon and needs timely recognition and treatment; it is usually secondary to overdose and renal or hepatic failure. In our case, toxicity was associated with GB use, probably by inhibition of CYP2D6 which is the main enzyme associated with the metabolism of flecainide. Clinicians need to be aware of the possible interactions between herbal remedies (in this case used for the prevention of COVID-19) and cardiovascular drugs that are used to treat chronic cardiovascular diseases.

Real-life drug-drug and herb-drug interactions in outpatients taking oral anticancer drugs: comparison with databases

PURPOSE

Due to polypharmacy and the rising popularity of complementary and alternative medicines (CAM), oncology patients are particularly at risk of drug-drug interactions (DDI) or herb-drug interactions (HDI). The aims of this study were to assess DDI and HDI in outpatients taking oral anticancer drug.

METHOD

All prescribed and non-prescribed medications, including CAM, were prospectively collected by hospital pharmacists during a structured interview with the patient. DDI and HDI were analyzed using four interaction software programs: Thériaque^®, Drugs.com^®, Hédrine, and Memorial Sloan Kettering Cancer Center (MSKCC) database. All detected interactions were characterized by severity, risk and action mechanism. The need for pharmaceutical intervention to modify drug use was determined on a case-by-case basis.

RESULTS

294 patients were included, with a mean age of 67 years [55-79]. The median number of chronic drugs per patient was 8 [1-29] and 55% of patients used at least one CAM. At least 1 interaction was found for 267 patients (90.8%): 263 (89.4%) with DDI, 68 (23.1%) with HDI, and 64 (21.7%) with both DDI and HDI. Only 13% of the DDI were found in Thériaque^® and Drugs.com^® databases, and 125 (2.5%) were reported with similar level of risk on both databases. 104 HDI were identified with only 9.5% of the interactions found in both databases. 103 pharmaceutical interventions were performed, involving 61 patients (20.7%).

CONCLUSION

Potentially clinically relevant drug interaction were frequently identified in this study, showing that several databases and structured screening are required to detect more interactions and optimize medication safety.

Evaluation of inhibitors of intestinal UDP-glucuronosyltransferases 1A8 and 1A10 using raloxifene as a substrate in Caco-2 cells: Studies with four flavonoids of Scutellaria baicalensis

UDP glucuronosyltransferases (UGTs) of the gastrointestinal tract play a crucial role in protection against the toxic effects of xenobiotics in the environment. UGTs such as UGT1A8 and UGT1A10 are predominantly expressed in gastrointestinal tissues. In this study, we examined the phase II metabolism of raloxifene in differentiated Caco-2 monolayers by inducing UGT1A8 and UGT1A10 expression in these cells. The present study evaluated the following four flavonoids of Scutellaria baicalensis as model herbal compounds: scutellarein, salvigenin, baicalein, and wogonin. All test compounds, endpoint substrates, and their metabolites were quantified using liquid chromatography and high-resolution mass spectrometry. The transepithelial electrical resistance values for the individual compounds were comparable regardless of whether they were measured individually. Salvigenin significantly inhibited UGT1A8 and UGT1A10 activities in a concentration-dependent manner. All individual compounds except scutellarein inhibited UGT1A8 and UGT1A10 activity at a concentration of 100 μM. In addition, all individual flavonoids at 100 μM, except wogonin, significantly increased the amount of raloxifene in the basolateral chambers. The positive control, canagliflozin, significantly inhibited both UGT1A8 and UGT1A10 activities. These findings suggest that the Caco-2 assay can be utilized for identifying UGT1A8 and UGT1A10 inhibitors and indicate the potential of salvigenin for enhancing the pharmacological effects of UGT substrate drugs.

Is it safe to take Radix Salvia Miltiorrhiza - Radix Pueraria Lobate product with warfarin and aspirin? A pilot study in healthy human subjects

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Salvia Miltiorrhiza (Danshen) and Radix Pueraria Lobate (Gegen) are officially listed in the Chinese Pharmacopoeia and have long been used together as a Compound Chinese Traditional Medicine (CCTM) for treatment of coronary heart diseases, which are often co-administered with aspirin or warfarin to patients suffering from cardiovascular diseases.

AIM OF STUDY

Since significant pharmacokinetic and pharmacodynamic interactions between Danshen-Gegen (DG) formula and aspirin/warfarin have been observed in our previous rat studies, the current study was proposed aiming to further verify such pharmacokinetic and pharmacodynamic interactions in healthy human subjects and explore related mechanisms.

MATERIALS AND METHODS

A 5-day, multiple dose, five-session clinical trial has been carried out (n = 14) with 2-week washout periods between sessions, during which the subjects would receive different combinations of the medications. Plasma samples were collected for pharmacokinetic evaluation, and whole blood samples were collected for pharmacodynamic evaluation. In addition, an in-vitro mechanistic study is conducted to investigate the role of danshensu on the anti-thrombotic and anti-platelet aggregation effects of warfarin and aspirin respectively.

RESULTS

Significant pharmacokinetic and pharmacodynamic herb-drug interactions were observed in healthy human subjects. pharmacokinetically, co-administration of DG with aspirin or warfarin could lead to a moderately increased AUC_0→t of aspirin and a decreased AUC_0→t of 7-hydroxyl warfarin respectively. The systemic exposure of danshensu (DSS, the marker component of DG) would be significantly increased after co-administration with warfarin. Pharmacodynamically, a reduction in systemic thromboxane B2 concentration was noticed after administration of DG with aspirin, which could be associated with the increased systemic exposure of aspirin and the synergistic effect of danshensu, aspirin and salicylic acid on cyclooxygenase (COX) inhibition. An offset on the warfarin induced soluble thrombomodulin induction was observed after its co-administration with DG, which could be partially attributed to the COX-2 inhibition effect of danshensu.

CONCLUSION

Our results indicated that co-administration of DG with aspirin/warfarin would lead to significant pharmacokinetic and pharmacodynamic herb-drug interactions in healthy human subjects.

Evaluation of acacetin inhibition potential against cytochrome P450 in vitro and in vivo

Acacetin is a natural flavonoid that is widely distributed in plants and possesses numerous pharmacological activities. The aim of the present study was to investigate the effects of acacetin on the activities of the cytochrome P450 family members CYP1A2, CYP2B1, CYP2C11, CYP2D1, CYP2E1, and CYP3A2 in rat liver microsomes in vitro and rats in vivo to evaluate potential herb-drug interactions by using a cocktail approach. Phenacetin, bupropion, tolbutamide, dextromethorphan, chlorzoxazone, and midazolam were chosen as the probe substrates. An ultra-performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous detection of the probe substrates and their metabolites. In vitro, the mode of acacetin inhibition of CYP2B1, CYP2C11, and CYP2E1 was competitive, while mixed inhibition was observed for CYP1A2 and CYP3A2. The Ki values in this study were less than 8.32 μM. In vivo, the mixed probe substrates were administered by gavage after daily intraperitoneal injection with 50 mg/kg acacetin or saline for 2 weeks. The main pharmacokinetic parameters, area under the plasma concentration-time curve (AUC), plasma clearance (CL), and maximum plasma concentration (C_max) of the probe substrates were significantly different in the experimental group than in the control group. Overall, the in vitro and in vivo results indicated that acacetin would be at high risk to cause toxicity and drug interactions via cytochrome P450 inhibition.

Influence of green tea consumption on endoxifen steady-state concentration in breast cancer patients treated with tamoxifen

Background

Many cancer patients use additional herbs or supplements in combination with their anti-cancer therapy. Green tea—active ingredient epigallocatechin-3-gallate (EGCG)—is one of the most commonly used dietary supplements among breast cancer patients. EGCG may alter the metabolism of tamoxifen. Therefore, the aim of this study was to investigate the influence of green tea supplements on the pharmacokinetics of endoxifen; the most relevant active metabolite of tamoxifen.

Methods

In this single-center, randomized cross-over trial, effects of green tea capsules on endoxifen levels were evaluated. Patients treated with tamoxifen for at least 3 months were eligible for this study. After inclusion, patients were consecutively treated with tamoxifen monotherapy for 28 days and in combination with green tea supplements (1 g twice daily; containing 300 mg EGCG) for 14 days (or vice versa). Blood samples were collected on the last day of monotherapy or combination therapy. Area under the curve (AUC_0–24h), maximum concentration (C_max) and minimum concentration (C_trough) were obtained from individual plasma concentration–time curves.

Results

No difference was found in geometric mean endoxifen AUC_0–24h in the period with green tea versus tamoxifen monotherapy (− 0.4%; 95% CI − 8.6 to 8.5%; p = 0.92). Furthermore, no differences in C_max (− 2.8%; − 10.6 to 5.6%; p = 0.47) nor C_trough (1.2%; − 7.3 to 10.5%; p = 0.77) were found. Moreover, no severe toxicity was reported during the whole study period.

Conclusions

This study demonstrated the absence of a pharmacokinetic interaction between green tea supplements and tamoxifen. Therefore, the use of green tea by patients with tamoxifen does not have to be discouraged.

Herb-drug interactions between the medicinal mushrooms Lingzhi and Yunzhi and cytotoxic anticancer drugs: a systematic review

BACKGROUND

Lingzhi and Yunzhi are medicinal mushrooms commonly used with cytotoxic chemotherapy in cancer patients in Asian countries. The current systematic review aims to identify potential pharmacokinetic or pharmacodynamic interactions from the existing literature to ensure their effective and safe combination usage in cancer patients.

METHODS

A systematic search was conducted on nine major Chinese and English databases, including China Journal Net, Allied and Complementary Medicine Database, and Ovid MEDLINE®, etc., to identify clinical, animal, and in-vitro studies that evaluate the effect of combined use of Lingzhi or Yunzhi with cytotoxic drugs. The Jadad scale was used to assess the quality of clinical studies.

RESULTS

This search identified 213 studies, including 77 clinical studies that reported on the combined use of cytotoxic drugs with Yunzhi (n = 56) or Lingzhi (n = 21). Majority of these clinical studies demonstrated modest methodological quality. In clinical practice, the most commonly used cytotoxic drugs with Lingzhi were cisplatin, 5-fluorouracil (5-FU) and paclitaxel, whereas Tegafur/uracil (UFT)/Tegafur, 5-FU, and mitomycin were the ones used more often with Yunzhi. Only two clinical pharmacokinetic studies were available showing no significant interactions between Polysaccharide K (PSK) and Tegafur. From the pharmacodynamic interactions perspective, combination uses of Yunzhi/Lingzhi with cytotoxic drugs in clinical practice could lead to improvement in survival (n = 31) and quality of life (n = 17), reduction in tumor lesions (n = 22), immune modulation (n = 38), and alleviation of chemotherapy-related side effects (n = 14) with no reported adverse effects.

CONCLUSION

Our findings suggest that the clinical combination use of Lingzhi or Yunzhi with cytotoxic drugs could enhance the efficacy and ameliorate the adverse effects of cytotoxic drugs, leading to improved quality of life in cancer patients. More high quality clinical studies including pharmacokinetic herb-drug interactions studies are warranted to verify these observations and mechanisms involved. Based on the high quality clinical data, pharmacoepidemiology methods and bioinformatics or data mining could be adopt for further identification of clinical meaningful herb-drug interactions in cancer therapies.

The use of dietary supplements by patients in the pre-operative period in the Czech Republic

Background The prevalence of dietary supplement use in the pre-operative period ranges from 4.8 to 80%. According to the Food and Drug Administration, some dietary supplements may show side effects before, during and after surgery. Objective The main aim of the study was to determine the prevalence of dietary supplement use in patients before surgery at University Hospital Hradec Kralove and the predictors of use. The secondary aim was to determine patient awareness regarding the correct use of and possible risks associated with dietary supplements. Setting University Hospital Hradec Kralove. Methods Between March 2017 and June 2018, a cross-sectional study focused on patients in the pre-operative period in different departments at University Hospital Hradec Kralove was conducted. The questionnaires were anonymous and entirely voluntary. The obtained data were evaluated using descriptive statistics and a regression model in Microsoft Excel 2016 and IBM SPSS version 24. Main outcome measure The prevalence and predictors of dietary supplement use in patients before surgery. Results 256 questionnaires were returned (a response rate of 77.41%). 111 dietary supplements were used by a total of 42% of the respondents in the 30-day period prior to surgery. Patients with a higher probability of dietary supplement use included patients with urogenital (OR 3.8, 95% CI 1.2, 12.1), otorhinolaryngological (OR 3.9, 95% CI 1.1, 13.8) and musculoskeletal health problems (OR 3.9, 95% CI 1.1, 13.8). The proportion of dietary supplement users increased with the number of drugs taken concomitantly, with the probability of use being more than three times higher compared with non-dietary supplement users (OR 3.4, 95% CI 1.2, 9.4). A total of 45.8% of the respondents thought there was no risk associated with their current use of dietary supplements and drugs. Conclusions There is a high prevalence of dietary supplement use in hospitalized patients, with independent predictors being comorbidity and polypharmacy. No official recommendations or guidelines exist for physicians and anaesthesiologists in the Czech Republic which focus on patients that use dietary supplements in the pre-operative period. National guidelines focusing on dietary supplement use in the pre-operative period would be appropriate.

Herb-drug interactions: a mechanistic approach

In India, traditional herbal medicines have been an essential part of therapy for the last centuries. However, a large portion of the general populace is using these therapies in combination with allopathy lacking a proper understanding of possible interactions (synergistic or antagonistic) between the herbal product and the allopathic drug. This is based on the assumption that herbal drugs are relatively safe, i.e. without side effects. We have established a comprehensive understanding of the possible herb-drug interactions and identified interaction patterns between the most common herbs and drugs currently in use in the Indian market. For this purpose, we listed common interactors (herbs and allopathic drugs) using available scientific literature. Drugs were then categorized into therapeutic classes and aligned to produce a recognizable pattern present only if interactions were observed between a drug class and herb in the scientific literature. Interestingly, the top three categories (with highest interactors), antibiotics, oral hypoglycemics, and anticonvulsants, displayed synergistic interactions only. Another major interactor category was CYP450 enzymes, a natural component of our metabolism. Both activation and inhibition of CYP450 enzymes were observed. As many allopathic drugs are known CYP substrates, inhibitors or inducers, ingestion of an interacting herb could result in interaction with the co-administered drug. This information is largely unavailable for the Indian population and should be studied in greater detail to avoid such interactions. Although this information is not absolute, the systematic literature review proves the existence of herb-drug interactions in the literature and studies where no interaction was detected are equally important.

Effects of Danshen tablets on pharmacokinetics of amlodipine in rats

CONTEXT

Danshen tablets (DST), an effective traditional Chinese multi-herbal formula, are often combined with amlodipine (ALDP) for treating coronary heart disease.

OBJECTIVE

This study investigated the effects of DST on the pharmacokinetics of ALDP and the potential mechanism.

MATERIALS AND METHODS

The pharmacokinetics of ALDP (1 mg/kg) in male Sprague-Dawley rats (n = 6), with or without pretreatment of DST (100 mg/kg for 7 d), were investigated using LC-MS/MS. The effects of DST on the metabolic stability of ALDP were also investigated using rat liver microsomes (RLM).

RESULTS

The results indicated that C_max (16.25 ± 2.65 vs. 22.79 ± 2.35 ng/ml), AUC_(0-t) (222.87 ± 59.95 vs. 468.32 ± 69.87 n gh/ml), and t_1/2 (10.60 ± 1.05 vs. 14.15 ± 1.59 h) decreased significantly when DST and ALDP were co-administered, which suggested that DST might influence the pharmacokinetic behaviour of ALDP when they are co-administered. The metabolic stability of ALDP was also decreased (23.6 ± 4.7 vs. 38.9 ± 5.2) with the pretreatment of DST.

DISCUSSION AND CONCLUSIONS

This study indicated that DST could accelerate the metabolism of ALDP in RLM and change the pharmacokinetic behaviours of ALDP. Accordingly, these results showed that the herb-drug interaction between DST and ALDP might occur when they were co-administered. Therefore, the clinical dose of ALDP should be increased when DST and ALDP are co-administered.

Interactions of ginseng with therapeutic drugs

Ginseng is the most frequently used herbal medicine for immune system stimulation and as an adjuvant with prescribed drugs owing to its numerous pharmacologic activities. It is important to investigate the beneficial effects and interaction of ginseng with therapeutic drugs. This review comprehensively discusses drug metabolizing enzyme- and transporter-mediated ginseng-drug interaction by analyzing in vitro and clinical results with a focus on ginsenoside, a pharmacologically active marker of ginseng. Impact of ginseng therapy or ginseng combination therapy on diabetic patients and of ginseng interaction with antiplatelets and anticoagulants were evaluated based on ginseng origin and ginsenoside content. Daily administration of Korean red ginseng (0.5-3 g extract; dried ginseng > 60%) did not cause significant herb-drug interaction with drug metabolizing enzymes and transporters. Among various therapeutic drugs administered in combination with ginseng, adjuvant chemotherapy, comprising ginseng (1-3 g extract) and anticancer drugs, was effective for reducing cancer-related fatigue and improving the quality of life and emotional scores. Limited information regarding ginsenoside content in each ginseng product and plasma ginsenoside concentration among patients necessitates standardization of ginseng product and establishment of pharmacokinetic-pharmacodynamic correlation to further understand beneficial effects of ginseng-therapeutic drug interactions in future clinical studies.

In vitro Inhibitory Effects of Isofraxidin on Human Liver Cytochrome P450 Enzymes

Isofraxidin is a Coumarin compound widely distributed in plants, such as the Umbelliferae or Chloranthaceae, and it possesses numerous pharmacological activities. However, whether isofraxidin affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear. In this study, the inhibitory effects of isofraxidin on the 8 human liver CYP isoforms (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19, and 2C8) were investigated in vitro using human liver microsomes. The results showed that isofraxidin inhibited the activity of CYP1A2, 3A4, and 2E1, with IC50 values of 23.01, 15.49, and 15.98 µmol/L, respectively, but that other CYP isoforms were not affected. Enzyme kinetic studies showed that isofraxidin was not only a noncompetitive inhibitor of CYP3A4 but also a competitive inhibitor of CYP1A2 and 2E1, with Ki values of 7.91, 10.14, and 9.30 µmol/L, respectively. In addition, isofraxidin is a time-dependent inhibitor for CYP3A4 with Kinact/KI value of 0.047/12.33 µmol/L-1min-1. The in vitro studies of isofraxidin with CYP isoforms indicate that isofraxidin has the potential to cause pharmacokinetic drug interactions with other coadministered drugs metabolized by -CYP1A2, 3A4, and 2E1. Further clinical studies are needed to evaluate the significance of this interaction.

Effects of triptolide on pharmacokinetics of amlodipine in rats by using LC-MS/MS

CONTEXT

Triptolide and amlodipine are often simultaneously used for reducing urine protein excretion after renal transplantation in China clinics.

OBJECTIVE

This study investigated the effects of triptolide on the pharmacokinetics of amlodipine in male Sprague-Dawley rats.

MATERIALS AND METHODS

The pharmacokinetics of amlodipine (1 mg/kg) with or without triptolide pre-treatment (2 mg/kg/day for seven days) were investigated using a sensitive and reliable LC-MS/MS method. Additionally, the inhibitory effects of triptolide on the metabolic stability of amlodipine were investigated using rat liver microsome incubation systems.

RESULTS

The results indicated that when the rats were pre-treated with triptolide, the Cmax of amlodipine increased from 13.78 ± 3.57 to 19.96 ± 4.56 ng/mL (p < 0.05), the Tmax increased from 4.04 ± 1.15 to 5.89 ± 1.64 h (p < 0.05), and the AUC0-t increased by approximately 104% (p < 0.05), which suggested that the pharmacokinetic behaviour of amlodipine was affected after oral co-administration of triptolide. Additionally, the metabolic half-life was prolonged from 22.5 ± 4.26 to 36.8 ± 6.37 min (p < 0.05) with the pre-treatment of triptolide.

CONCLUSIONS

In conclusion, these results indicated that triptolide could affect the pharmacokinetics of amlodipine, possibly by inhibiting the metabolism of amlodipine in rat liver when they are co-administered.

Effects of Ginkgo leaf tablets on the pharmacokinetics of losartan and its metabolite EXP3174 in rats and its mechanism

CONTEXT

Ginkgo leaf tablets (GLTs) and losartan are often simultaneously used for the treatment of hypertension in Chinese clinics. However, the herb-drug interaction between GLT and losartan is still unknown.

OBJECTIVE

This study investigates the effects of GLT on the pharmacokinetics of losartan and its metabolite EXP3174 in rats and its potential mechanism.

MATERIALS AND METHODS

The pharmacokinetic profiles of losartan and EXP3174 of orally administered losartan (10 mg/kg) with or without GLT pretreatment (80 mg/kg/day for 10 days) in Sprague-Dawley rats were determined. In vitro, the effects of GLT on the metabolic stability of losartan were investigated with rat liver microsomes.

RESULTS

The C_max (1.22 ± 0.25 vs 1.85 ± 0.37 μg/mL) and the AUC_(0-t) (6.99 ± 1.05 vs 11.94 ± 1.79 mg·h/L) of losartan increased significantly (p < 0.05) with GLT pretreatment, while the C_max (1.05 ± 0.19 vs 0.72 ± 0.12 μg/mL) of EXP3174 decreased significantly (p < 0.05) compared to the control. The t_1/2 of losartan was prolonged significantly from 3.94 ± 0.62 to 4.75 ± 0.52 h (p < 0.05). The metabolic stability of losartan was increased from 37.4 min to 59.6 min with GLT pretreatment.

DISCUSSION AND CONCLUSIONS

The results indicate that GLT might increase the plasma concentration of losartan and decrease the concentration of EXP3174 through inhibiting the metabolism of losartan.

In vitro inhibitory effects of pristimerin on human liver cytochrome P450 enzymes

1.Pristimerin (PTM) is a biological component isolated from Chinese herbal plant Celastrus and Maytenus spp. and it possesses numerous pharmacological activities. However, whether PTM affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear. 2.In this study, the inhibitory effects of PTM on the eight human liver CYP isoforms (i.e. 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19 and 2C8) were investigated in vitro using human liver microsomes (HLMs). 3.The results showed that PTM inhibited the activity of CYP1A2, 3A4 and 2C9, with IC ₅₀ values of 21.74, 15.88 and 16.58 μM, respectively, but that other CYP isoforms were not affected. Enzyme kinetic studies showed that PTM was not only a non-competitive inhibitor of CYP3A4, but also a competitive inhibitor of CYP1A2 and 2C9, with K_i values of 7.33, 11.60 and 8.09 μM, respectively. In addition, PTM is a time-dependent inhibitor for CYP3A4 with K_inact /K_I value of 0.049/11.62 μM^-1min^-1. 4.The in vitro studies of PTM with CYP isoforms indicate that PTM has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP1A2, 3A4 and 2C9. Further clinical studies are needed to evaluate the significance of this interaction.

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

ETHNOPHARMACOLOGICAL RELEVANCE

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

AIM OF THE STUDY

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Concurrent administration of anticancer chemotherapy drug and herbal medicine on the perspective of pharmacokinetics

With an increasing number of cancer patients seeking an improved quality of life, complementary and alternative therapies are becoming more common ways to achieve such improvements. The potential risks of concurrent administration are serious and must be addressed. However, comprehensive evidence for the risks and benefits of combining anticancer drugs with traditional herbs is rare. Pharmacokinetic investigations are an efficient way to understand the influence of concomitant remedies. Therefore, this study aimed to collect the results of pharmacokinetic studies relating to the concurrent use of cancer chemotherapy and complementary and alternative therapies. According to the National Health Insurance (NHI) database in Taiwan and several publications, the three most commonly prescribed formulations for cancer patients are Xiang-Sha-Liu-Jun-Zi-Tang, Jia-Wei-Xiao-Yao-San and Bu-Zhong-Yi-Qi-Tang. The three most commonly prescribed single herbs for cancer patients are Hedyotis diffusa, Scutellaria barbata, and Astragalus membranaceus. Few studies have discussed herb-drug interactions involving these herbs from a pharmacokinetics perspective. Here, we reviewed Jia-Wei-Xiao-Yao-San, Long-Dan-Xie-Gan-Tang, Curcuma longa and milk thistle to provide information based on pharmacokinetic evidence for healthcare professionals to use in educating patients about the risks of the concomitant use of various remedies.

Antidiabetic, antihyperlipidemic activities and herb-drug interaction of a polyherbal formulation in streptozotocin induced diabetic rats

Background

Ojamin (OJ), a polyherbal antidiabetic formulation, is extensively used as a food supplement to control diabetes alone or along with synthetic antidiabetic agents. However, it's phytochemical and pharmacological investigations are lacking.

Objective

The present study was undertaken to study antidiabetic and antihyperlipidemic potentials of OJ and its interaction with Metformin in streptozotocin (STZ)-induced diabetic rats.

Materials and methods

Diabetes was induced in Wistar rats by single intraperitoneal (i.p.) injection of streptozotocin (60 mg/kg). Antidiabetic, antihyperlipidemic activities of OJ were evaluated at dose of 0.28 ml/kg by estimating biochemical changes in urine, serum and liver tissue homogenate and histological changes in liver and pancreatic tissues. Metformin (100 mg/kg, p.o.) was used as reference standard drug.

Results

Results indicate that STZ administration caused hyperglycemia, increased serum glycosylated hemoglobin content, altered serum lipid profile, polyuria, decreased liver glycogen content and histological changes in liver and pancreatic tissues. This elevated serum glucose level and urine volume was significantly decreased by OJ. Supplementation with OJ produced significant improvement in serum lipid profile and glycosylated hemoglobin content along with significant increase in the liver glycogen content. OJ treatment also restored histological changes in liver and pancreatic tissue near to the normal. The observed antidiabetic and hypolipidemic effects of OJ were superior to Metformin. Co-treatment of diabetic rats with OJ and Metformin failed to control blood glucose levels.

Conclusion

It is concluded that the OJ possesses significant antidiabetic and antihyperlipidemic activities in rats. However, co-administration of OJ and Metformin is cautioned.

Unmonitored use of herbal medicine by patients with breast cancer: reframing expectations

PURPOSE

To identify the unmonitored use of herbal medicine by female patients with breast cancer, examining the impact of an integrative physician (IP) consultation on this practice.

METHODS

The files of 269 female patients with breast cancer following an IP consultation were surveyed retrospectively for use of herbal medicine for cancer-related goals. Expectations from the IP consultation and adherence to the IP-guided treatments were examined as well.

RESULTS

Among the cohort, 111 (41.3%) reported using herbal medicine for cancer-related goals, unmonitored by their oncology healthcare professional. Factors predicting herbal medicine use were the adoption of dietary changes (odds ratio = 13.6, p < 0.001, CI 7.16-26.0) and the expectation that the IP consultation and treatments would address cancer-related goals (odds ratio = 3.29, p = 0.001, CI 1.64-6.6). Patients with metastatic disease were more likely to be using herbal medicine than non-users (34.5 vs. 22.8%; p = 0.088), as were those who had consulted with a complementary/alternative medicine practitioner (54.9 vs. 20.8%; p = 0.005). The IP advised 17 patients (15.3%) to stop taking specific herbal products due to safety-related concerns; and 10 patients to take dietary supplements for relief of specific symptoms. Herbal medicine users were less likely than non-users to adhere to the IP-recommended treatment program (34.7 vs. 48.3%; p = 0.037).

CONCLUSIONS

Unmonitored use of herbal medicine by patients with breast cancer is more frequent among those adopting dietary changes for cancer-related goals. Integrative physicians provide evidence-based guidance on the safe and effective use of herbal products, and reframe patient expectations from cancer-related goals to reducing symptoms and improving quality of life.

Pharmacokinetic herb-drug interaction of Xuesaitong dispersible tablet and aspirin after oral administration in blood stasis model rats

BACKGROUND

Xuesaitong dispersible tablet (XST) product has been clinically proven to be effective for treating cardio-cerebrovascular disease. Furthermore, herb-drug interactions between the XST product and drugs that are commonly co-administered, such as aspirin (ASA), must be explored to ensure safe clinical use.

STUDY DESIGN AND METHODS

The current study aims to investigate whether the XST product interacts with ASA when they are administered concomitantly to ensure safety and efficacy. A ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous determination of ginsenoside Rg1 (Rg1), ginsenoside Rd (Rd), notoginsenoside R1 (R1) and salicylic acid (SA) in rat plasma to investigate the pharmacokinetic interaction of XST and ASA in blood stasis model rats.

RESULTS AND CONCLUSION

The ASA and XST combination noticeably altered R1 and Rg1 absorption, distribution and disposition. This study indicates that co-administration of XST and ASA can cause an apparent herb-drug pharmacokinetic interaction in blood stasis model rats.

Evaluation of herbal antimalarial MAMA decoction-amodiaquine combination in murine malaria model

CONTEXT

Co-administration of amodiaquine with MAMA decoction (MD), an herbal antimalarial drug comprising the leaves of Mangifera indica L. (Anacardiaceae), Alstonia boonei De Wild (Apocynaceae), Morinda lucida Benth (Rubiaceae) and Azadirachta indica A. Juss (Meliaceae) was investigated. The practice of concurrent administration of herbal medicines with orthodox drugs is currently on the increase globally.

OBJECTIVE

The study was designed to investigate the possible enhancement of the antimalarial potency as well as possible herb-drug interaction resulting from concurrent administration of MAMA decoction with amodiaquine (AQ).

MATERIALS AND METHODS

Combinations of MD with AQ were investigated in chloroquine (CQ)-sensitive Plasmodium berghei NK 65 in varying oral doses (mg/kg) at: sub-therapeutic [MD30 + AQ1.25], therapeutic [MD120 + AQ10] and median effective [MD40 + AQ3.8], using chemosuppressive and curative antimalarial test models. Secondly, P. berghei ANKA (CQ-resistant)-infected mice were orally treated with MD 120, 240, [MD120 + AQ10] and [MD240 + AQ10] mg/kg, using both models. The survival times of mice were monitored for 28 d.

RESULTS

ED50 values of MD and AQ were 48.8 and 4.1 mg/kg, respectively. A total parasite clearance of CQ-sensitive P. berghei NK65 was obtained with the therapeutic combination dose in the curative test giving an enhanced survival time. In CQ-resistant P. berghei ANKA-infected mice, [MD120 + AQ10] and [MD240 + AQ10] mg/kg gave comparable activities with AQ (10 mg/kg) in both models.

CONCLUSION

The therapeutic combination dose gave total parasite clearance of CQ-sensitive P. berghei NK65, whereas none of the doses tested showed notable activity against CQ-resistant P. berghei ANKA.

Chemical and pharmacological evaluations on the extract of Scutellaria baicalensis Georgi (Huang-Qin) prepared by various extraction methods

Background

This study reported a comprehensive approach (comparing the extraction yields, chemical profiles, antioxidant properties and CYP450-inhibitory effects) to evaluated the effectiveness of various extraction methods [microwave-assisted extraction using water (MAE-W), heat reflux extraction using water (HRE-W), ultrasonic extraction using 70 % ethanol and ultrasonic extraction using ethanol (UE-E)] for Huang-Qin (HQ), the dried root of Scutellaria baicalensis Georgi.

Results

The HQ extraction efficiency by MAE-W was the best. The chemical profiles of extracts obtained using HRE-W and MAE-W were similar; whereas more flavones but less flavone glycosides were detected in the UE-E extract. There was no difference in the antioxidant properties among different extracts. In vitro human liver microsome assays illustrated that all extracts possessed herb–drug interaction potentials but the UE-E extract are shown with a potent interaction with CYP3A4-metabolized drugs.

Conclusion

MAE-W is a favorable method for the preparation of HQ extracts based on extraction yield, pharmacological properties and safety.

In vivo prediction of CYP-mediated metabolic interaction potential of formononetin and biochanin A using in vitro human and rat CYP450 inhibition data

Formononetin (FMN) and Biochanin A (BCA) are the principal isoflavones present in commercially available extracts of red clover that are widely been consumed for various health benefits. We investigated the in vitro effects of FMN and BCA on catalytic activity of human/rat cytochrome P450 enzymes to assess the drug interaction potential of red clover. IC50 and Ki values of FMN and BCA for CYPs were determined in human/rat liver microsomes. FMN and BCA showed concentration-dependent inhibition of CYP1A2 activity with IC50 values of 13.42 and 24.98μM in human liver microsomes and 38.57 and 11.86μM in rat liver microsomes, respectively. The mode of inhibition of human CYP1A2 by FMN was found to be competitive with apparent Ki value of 10.13±1.96μM. FMN also inhibited human CYP2D6. BCA exerted moderately inhibitory effects on human CYP2C9. The predicted in vivo inhibition for CYP1A2 was insignificant (R value <1.1) at hepatic level while at intestinal level, it was significant (R value >11). The inhibitory effects on other CYPs were found to be minimal. Red clover may be considered safe to be consumed along with co-prescribed medications; however, precaution must be taken while co-administering it with CYP1A2 substrates.

Herb-drug interactions between Scutellariae Radix and mefenamic acid: Simultaneous investigation of pharmacokinetics, anti-inflammatory effect and gastric damage in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellariae Radix (SR), the dried root of Scutellariae baicalensis Georgi, has a lot in common with non-steroidal anti-inflammatory drugs (NSAIDs). Their similarities in therapeutic action (anti-inflammation) and metabolic pathways (phase II metabolisms) may lead to co-administration by patients with the potential of pharmacokinetic and/or pharmacodynamic interactions. The current study aims to investigate the potential interactions between SR and an NSAID, mefenamic acid (MEF), on the overall pharmacokinetic dispositions, anti-inflammatory effects and adverse effects in rats.

MATERIALS AND METHODS

The current study simultaneously monitored the pharmacokinetic and pharmacodynamic interactions in a single animal. Four groups of Sprague-Dawley rats (n=7 each) received oral doses of a standardized SR extract (300mg/kg, twice daily), MEF (40mg/kg, daily), combination of SR extract and MEF, and vehicle control, respectively, for 5 days. On Day 5, blood samples were collected after first dose over 24h for the determination of (1) plasma concentrations of SR bioactive components, MEF and its metabolites by LC-MS/MS, and (2) prostaglandin E2 (PGE2) production and cyclooxygenase-2 (COX-2) gene expression by ex vivo analyses using LPS-stimulated RAW264.7 macrophage cells, ELISA and real time-PCR. After the rats were sacrificed, stomachs were isolated to assess their gross mucosal damage. Statistical comparisons were conducted using ANOVA and t-test.

RESULTS

Minimal pharmacokinetic interaction between SR extract and MEF was observed. Co-administration of SR extract and MEF did not significantly alter the plasma concentration-time profile or the pharmacokinetic parameters such as Cmax, AUC0→24, Tmax or clearance. Pharmacodynamic interaction via the COX-2 pathway was observed. The PGE2 level in LPS-stimulated RAW264.7 cells treated with plasma collected from control group over the 24h sampling (AUC0→24[PGE2]) was 191981±8789pg/mlhr, which was significantly reduced to 174,780±6531 and 46,225±1915pg/mlhr by plasma collected from rats administered with SR extract and MEF, respectively. Co-administration of SR extract and MEF further potentiated the PGE2 inhibition, with an AUC0→24[PGE2] of 37013±2354pg/mlhr (p<0.05, compared to SR or MEF group). By analyzing the COX-2 gene expression, SR extract significantly prolonged the COX-2 inhibitory effect of MEF over the 24h (p<0.05). Furthermore, the MEF-induced stomach ulcer after the 5-day treatment, as evidenced by the increased gross ulcer index and sum of lesion length (p<0.05, compared to control), could be alleviated by co-administration with SR extract (p<0.05).

CONCLUSIONS

Co-administration of SR extract and MEF potentiated the anti-inflammatory effects, alleviated the MEF-induced stomach adverse effect while having minimal pharmacokinetic interactions. Our findings provide insight for combination therapy of SR extract and MEF against inflammatory diseases.

Herb-drug interaction between an anti-HIV Chinese herbal SH formula and atazanavir in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

With the prevalent use of highly active antiretroviral therapy (HAART) for AIDS patients since 1996, the mortality of HIV/AIDS patients has been remarkably decreased. With long-term use of HAART, drug resistance and side effects of antiretrovirals have been frequently reported, which not only reduce the efficacy, but also decreases the tolerance of patients. Traditional herbal medicine has become more popular among HIV/AIDS patients as adjuvant therapy to reduce these adverse effects of HAART. SH formula is a Chinese herbal formula consisting of five traditional Chinese herbs including Morus alba L., Glycyrrhiza glabra L., Artemisia capillaris Thumb., Astragalus membranaceus Bge., and Carthamus tinctorius L. SH formula is clinically used for HIV treatment in Thailand. However, the possible pharmacokinetic interactions between these Chinese herbs and antiretroviral drugs have not been well documented. The aim of this study was to investigate the potential herb-drug interaction between SH herbal Chinese formula and the antiretroviral drug atazanavir (ATV).

MATERIALS AND METHODS

The combination effect of SH formula and ATV on HIV protease was studied in HIV-1 protease inhibition assay in vitro. The inhibition of SH formula on rat CYP3A2 was assessed by detecting the formation of 1'-OH midazolam from midazolam in rat liver microsomes in vitro. The in vivo pharmacokinetic interaction between SH formula and ATV was investigated by measuring time-dependent plasma concentrations of ATV in male Sprague-Dawley rats with liquid chromatography-mass spectrometry.

RESULTS

Through the in vitro HIV-1 protease inhibition assay, combination of SH formula (41.7-166.7 μg/ml) and ATV (16.7-33.3 ng/ml) showed additive inhibition on HIV-1 protease activity than SH formula or ATV used alone. In vitro incubation assay indicated that SH formula showed a weak inhibition (IC50=231.2 µg/ml; Ki=98.2 µg/ml) on CYP3A2 activity in rat liver microsomes. In vivo pharmacokinetic study demonstrated that SH formula did not affect the metabolism of ATV in rats.

CONCLUSIONS

Our study demonstrated for the first time that there is no metabolism-based herb-drug interaction between SH formula and ATV in rats, but this combination enhances the inhibition potentials against HIV protease activity. This observation may support the combinational use of anti-HIV treatment in human.

Multifaceted interaction of the traditional Chinese medicinal herb Schisandra chinensis with cytochrome P450-mediated drug metabolism in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra chinensis (SC), officially listed as a sedative and tonic in the Chinese Pharmacopoeia, has been used as a common component in various prescriptions in Traditional Chinese Medicine (TCM) and more recently in western medicine for its antihepatotoxic effect. To assess the possible herb-drug interaction, effects of SC extracts on hepatic cytochrome P450 (P450, CYP) enzymes were studied.

MATERIAL AND METHODS

Effects of SC extracts on rat hepatic CYP450 enzymes in vitro and in vivo were investigated by probe substrates method, real-time RT-PCR assay and Western blotting analysis. Furthermore, the effects of SC alcoholic extract on the PK of four SC lignans and the drugs possibly co-administrated in vivo were studied in male Sprague-Dawley rat.

RESULTS

SC aqueous extract and alcoholic extract showed significant inhibitory effect on the activities of rat liver microsomal CYP1A2, 2C6, 2C11, 2D2, 2E1 and 3A1/2 in vitro. Multiple administrations of SC aqueous extract (1.5g/kg, qd×7d) and alcoholic extract (1.5g/kg, qd×7d) increased the activities, mRNA and protein expressions of CYP2E1 and CYP3A1/2, and meanwhile, inhibited the activities and mRNA expression of CYP2D2 in vivo. The in vivo metabolism of four SC lignans, such as schisandrin, schisantherin A, deoxyshisandrin and γ-schisandrin, and chlorzoxazone was significantly accelerated, exhibited by the reduced AUC and increased CLz/F, by 7-day pretreatment with SC alcoholic extract. However, both single and multiple dosing treatments of SC alcoholic extract remarkably decreased the in vivo metabolism of tacrolimus indicated by the enhanced AUC (7-12 fold) and elevated Cmax (10 fold).

CONCLUSION

These results revealed that the SC extracts exhibited multifaceted effects on rat hepatic CYP450 enzymes. Herb-drug interaction should be paid intense attention between SC components and drugs metabolized by different CYP450 enzymes.

The use of Chinese herbal products and its influence on tamoxifen induced endometrial cancer risk among female breast cancer patients: a population-based study

ETHNOPHARMACOLOGICAL RELEVANCE

The increased practice of traditional Chinese medicine (TCM) worldwide has raised concerns regarding herb-drug interactions. The purpose of our study was to analyze the use of Chinese herbal products (CHPs) and to estimate the influence of the use of CHP on tamoxifen induced endometrial cancer risk among female breast cancer patients in Taiwan.

METHODS

All patients newly diagnosed with invasive breast cancer receiving tamoxifen treatment from January 1, 1998 to December 31, 2008 were selected from the National Health Insurance Research Database. The usage, frequency of service, and CHPs prescribed among the 20,466 tamoxifen-treated female breast cancer patients were analyzed. The logistic regression method was employed to estimate the odds ratios (ORs) for utilization of CHPs. Cox proportional hazard regression was performed to calculate the hazard ratios (HRs) for subsequent endometrial cancer for CHP non-users and CHP users among female breast cancer patients who had undergone tamoxifen treatment.

RESULTS

More than half of the subjects had ever used a CHP. Jia-Wei-Xiao-Yao-San (Augmented Rambling Powder) and Shu-Jing-Huo-Xue-Tang (Channel-Coursing Blood-Quickening Decoction) were the two most commonly used CHPs. The HR for the development of endometrial cancer among CHP users was 0.50-fold (95% CI=0.38-0.64) compared to that of CHP non-users.

CONCLUSION

More than half of the study subjects had ever used a CHP. Jia-Wei-Xiao-Yao-San was the most commonly used CHP. Among female breast cancer patients who had undergone tamoxifen therapy, CHP consumption decreased the risk of subsequent endometrial cancer. Exploring potential Chinese herb-tamoxifen interactions and integrating both healthcare approaches are beneficial to the overall health outcomes of tamoxifen-treated female breast cancer patients.

Dose-response of oridonin on hepatic cytochromes P450 mRNA expression and activities in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Oridonin, the major terpene found in Rabdosia rubescens, is widely used as a dietary supplement or therapeutic drug. The effects of oridonin on drug processing genes, such as cytochrome P450 and nuclear receptors, were still unclear. Therefore, the present study investigated the influence of oridonin on the hepatic drug metabolizing system to evaluate the safety through its drug interaction potential.

MATERIALS AND METHODS

In this study, eight-week-old male C57BL/6 mice were treated oridonin orally (0, 25, 50, 100, 200 mg/kg, i.g.) for 15 days. The effects of oridonin on major Cyps in mice livers were examined at both the mRNA and enzyme activity levels.

RESULTS

In general, there are no significant influence of various dose of oridonin on mice liver function. However, oridonin significantly increased Cyps (1a, 2a, 2d, 2e, 2c and 3a family) mRNA expression. In addition, it could induce Cyps activity in microsome incubation at maximum dosage. To our knowledge, it is the first time to identify oridonin as a Cyps inducer in vivo. It also promotes the expression of CAR, PXR and POR.

CONCLUSION

These results indicate that, if studies in mice extrapolate to humans by orthologous genes, oridonin appears to be a risk to herb-drug interactions due to its induction effects on drug processing genes expression and activation.

Cytochrome P450 inhibitory potential and RP-HPLC standardization of trikatu--a Rasayana from Indian Ayurveda

ETHNOPHARMACOLOGICAL RELEVANCE

Trikatu is a very well known 'Rasayana' in Ayurveda and widely used as a polyherbal ayurvedic formulation in India. It consists of three well known plants, viz., Piper longum (PL), Piper nigrum (PN) and Zingiber officinale (ZO) in equal ratio. Trikatu has been prescribed for cough, cold, fever, asthma, respiratory problems and improvement of digestive disorders. The aim of the present study was to investigate the effect of individual ingredients of trikatu namely PL, PN, and ZO and formulations [Marketed formulation (MF) and laboratory formulation (LF)] on drug metabolizing enzymes (CYP3A4 and CYP2D6), to assess its herb-drug interaction potential through cytochrome P450 inhibition assays. Further this work was aimed to develop an RP-HPLC method for the identification and quantification of piperine and 6-gingerol in the crude drug trikatu.

MATERIALS AND METHODS

Enzyme inhibition effect of LF, MF, PL, PN and ZO was explored through CYP450-CO complex assay using rat liver microsomes (RLM) and a fluorescence screening method using individual isoenzymes (CYP3A4 and CYP2D6). The RP-HPLC method was developed for the identification and quantification of piperine and 6-gingerol in LF, MF and individual plant materials at the concentration of 1mg/mL.

RESULTS

RP-HPLC analysis confirmed the presence of piperine and 6-gingerol in LF and MF [Piperine: 7.89±2.12% (w/w) (MF), 6.70±2.13% (w/w) (LF)]; [6-gingerol: 5.3±1.21% (w/w) (MF), 4.95±2.34% (w/w) (LF)]. Inhibitory potential of MF and LF in CYP450-CO complex assay was found to be 37.54±3.12% (MF) and 35.12±2.31% (LF) and against CYP2D6 and CYP3A4 was estimated to be IC50 251.30±3.98 and 245.23±1.92μg/mL and IC50 225.50±1.02 and 223.254±0.92μg/mL respectively.

CONCLUSIONS

Different concentrations of the trikatu formulation and its individual components showed significantly (p<0.001) less inhibitory activity on individual isoenzymes as compared to the positive control. The crude drug exhibited inhibitory potential against the CYP450 enzymes in a concentration dependent manner. Outcome of the present study demonstrated that trikatu has less interaction potential with drug metabolizing enzymes.

Effect of Tacrolimus on the pharmacokinetics of bioactive lignans of Wuzhi tablet (Schisandra sphenanthera extract) and the potential roles of CYP3A and P-gp

We recently reported that Wuzhi tablet (WZ), a preparation of the ethanol extract of Wuweizi (Schisandra sphenanthera), had significant effects on blood concentrations of Tacrolimus (FK506) in renal transplant recipients and rats. The active lignans in WZ are schisandrin A, schisandrin B, schisandrin C, schisandrol A, schisandrol B, schisantherin A, and schisantherin B. Until now, whether the pharmacokinetics of these lignans in WZ would be affected by FK506 remained unknown. Therefore, this study aimed to investigate whether and how FK506 affected pharmacokinetics of lignans in WZ in rats and the potential roles of CYP3A and P-gp. After a single oral co-administration of FK506 and WZ, the blood concentration of lignans in WZ was decreased by FK506; furthermore, the AUC of schisantherin A, schisandrin A, schisandrol A and schisandrol B was only 64.5%, 47.2%, 55.1% and 57.4% of that of WZ alone group, respectively. Transport study in Caco-2 cells showed that these lignans were not substrates of P-gp, suggesting decreased blood concentration of lignans by FK506 was not via P-gp pathway. Metabolism study in the human recombinant CYP 3A showed that these lignans had higher affinity to CYP3A than that of FK506, and thus had a stronger CYP3A-mediated metabolism. It was concluded that the blood concentrations of these lignans were decreased and their CYP3A-mediated metabolisms were increased in the presence of FK506 since these lignans had higher affinity to CYP3A.

Concurrent Use of Conventional Drugs with Chinese Herbal Products in Taiwan: A Population-based Study

The increased use of Chinese herbal products (CHPs) worldwide has raised the concern of herb-drug interactions. The aim of this study was to determine the prevalence and utilization patterns of concurrent use of conventional drugs and CHPs in Taiwan. The usage and frequency of services in the co-prescription of a CHP and a conventional drug were evaluated. Subjects were recruited from a simple random sample of 1,000,000 subjects from over 22 million beneficiaries of the National Health Insurance in 2007. The logistic regression method was employed to estimate the odds ratios (ORs) for the co-prescription of a CHP and a conventional drug (CH + D) and a conventional drug alone (D-alone). The prevalence of the CH + D was 14.1%. Females, regular salary earners, and elderly (65 years and above) were more likely to consume a CHP and a conventional drug concurrently. Painkillers, especially acetaminophen, and anti-cough medicines were the top two conventional drugs that were most frequently co-prescribed with a CHP. Anti-cough medication is the most common conventional drug co-prescribed with CHP, after painkillers. We recommend that safety issues be investigated in future research and integrating both healthcare technologies may be beneficial for the overall health and quality of life of patients.

In vitro to in vivo evidence of the inhibitor characteristics of Schisandra lignans toward P-glycoprotein

Concomitant administration of herbal medicines with drugs that are P-glycoprotein (P-gp) substrates may produce significant herb-drug interactions. The purpose of this study was to evaluate the effects of Schisandra lignans extract (SLE) on P-gp thoroughly in vitro and in vivo, and to investigate the possible P-gp-based herb-drug interactions. In the in vitro experiments, the effect of SLE on the uptake and transport for P-gp substrates in Caco-2, LLC-PK1 and L-MDR1 cells were carefully investigated. Verapamil, a known P-gp inhibitor, was used as a positive control drug. Results shown that, 10 μM verapamil and SLE (0.5, 2.0, and 10.0 μg/ml) were observed to significantly enhance the uptake and inhibit the efflux ratio of P-gp substrates in Caco-2 and L-MDR1 cells. In vivo experiments showed that single-dose SLE at 500 mg/kg could increase the area under the plasma concentration time curve of digoxin and vincrisine significantly without affecting terminal elimination half-time. Long-term treatment with SLE for continuous 10 days could also increase the absorption of P-gp substrates with greatly down regulation of P-gp expression in rat intestinal and brain tissues. In conclusion, SLE was a strong P-gp inhibitor, which indicated a potential herb-drug interaction when SLE was co-administered with P-gp substrate drugs.

An overview of the evidence and mechanisms of herb-drug interactions

Despite the lack of sufficient information on the safety of herbal products, their use as alternative and/or complementary medicine is globally popular. There is also an increasing interest in medicinal herbs as precursor for pharmacological actives. Of serious concern is the concurrent consumption of herbal products and conventional drugs. Herb-drug interaction (HDI) is the single most important clinical consequence of this practice. Using a structured assessment procedure, the evidence of HDI presents with varying degree of clinical significance. While the potential for HDI for a number of herbal products is inferred from non-human studies, certain HDIs are well established through human studies and documented case reports. Various mechanisms of pharmacokinetic HDI have been identified and include the alteration in the gastrointestinal functions with consequent effects on drug absorption; induction and inhibition of metabolic enzymes and transport proteins; and alteration of renal excretion of drugs and their metabolites. Due to the intrinsic pharmacologic properties of phytochemicals, pharmacodynamic HDIs are also known to occur. The effects could be synergistic, additive, and/or antagonistic. Poor reporting on the part of patients and the inability to promptly identify HDI by health providers are identified as major factors limiting the extensive compilation of clinically relevant HDIs. A general overview and the significance of pharmacokinetic and pharmacodynamic HDI are provided, detailing basic mechanism, and nature of evidence available. An increased level of awareness of HDI is necessary among health professionals and drug discovery scientists. With the increasing number of plant-sourced pharmacological actives, the potential for HDI should always be assessed in the non-clinical safety assessment phase of drug development process. More clinically relevant research is also required in this area as current information on HDI is insufficient for clinical applications.