NATURAL HEALTH PRODUCTS AND DRUG DISPOSITION

Sinomenine pretreatment alleviates hepatic ischemia/reperfusion injury through activating Nrf-2/HO-1 pathway

INTRODUCTION

Ischemia-reperfusion (IR) injury is induced by an interrupted blood flow and succeeding blood restoration, which is common in the operation of liver transplantation. Serious IR injury is a major reason leading to transplant failure. Hepatic IR is featured by excessive inflammatory response, oxidative stress, and apoptosis. Sinomenine (SIN) is derived from the herb Sinomeniumacutum and shows properties of anti-inflammation and antiapoptosis in multiple IR-induced organ injuries. However, the effect of SIN in hepatic IR has not been investigated.

METHODS

This study aims to investigate impacts of SIN on hepatic IR and the involved signaling pathway. An in vivo rat model of syngeneic orthotopic liver transplantation was constructed to induce the hepatic IR injury.

RESULTS

Results showed that SIN pretreatment provided a significant prevention against IR-induced hepatic injury as manifested by the downregulated activities of serum alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase, the alleviatedoxidative stress as shown by increased activities of serum superoxide dismutase and glutathione peroxidase, and decreased serum level of malondialdehyde, the suppressed inflammatory responses as shown by downregulated serum tumor necrosis factor-α, interleukin (IL)-6, IL-8 levels, and upregulated IL-10 level, as well as attenuated apoptosis as shown by decreased protein expression of cleaved caspase-3 and -9. In line with these results, SIN pretreatment also alleviatedthe hepatic histopathological changes in IR rats and induced Nrf-2/HO-1 activation. The use of brusatol, a selective inhibitor for Nrf-2, effectively reversed SIN-induced above effects.

CONCLUSIONS

Altogether, our results demonstrate that SIN might be a useful therapeutic drug for preventing hepatic IR-induced injury during clinical liver transplantation.

NMR technique and methodology in botanical health product analysis and quality control

Botanicals have played an important role in maintaining human health and well-being throughout history. During the past few decades in particular, the use of botanical health products has gained more popularity. Whereas, quality, safety and efficacy concerns have continuously been critical issues due to the intrinsic chemical complexity of botanicals. Chemical analytical technologies play an imperative role in addressing these issues. Nuclear magnetic resonance (NMR) spectroscopy has proven to be a powerful and useful tool for the investigation of botanical health products. In this review, NMR techniques and methodologies that have been successfully applied to the research and development of botanical health products in all stages, from plants to products, are discussed and summarized. Furthermore, applications of NMR together with other analytical techniques in a variety of domains of botanical health products investigation, such as plant species differentiation, adulteration detection, and bio-activity evaluation, are discussed and illustrated with typical examples. This article provides an overview of the potential uses of NMR techniques and methodologies in an attempt to further promote their recognition and utilization in the field of botanical health products analysis and quality control.

Evaluation of potential herb-drug interactions based on the effect of Suxiao Jiuxin Pill on CYP450 enzymes and transporters

ETHNOPHARMACOLOGY RELEVANCE

Suxiao jiuxin pill (SJP) is a Chinese medical drug with anti-inflammatory, anti-apoptotic, and vasodilatory function. It is widely used in combination with other drugs for the treatment of coronary heart disease (CHD) and angina. Nevertheless, the effect of SJP on Cytochrome P450 (CYP450) enzymes and transporters' activity related to drug metabolism is rarely studied.

OBJECTIVE

The aim of this study was to investigate the effect of SJP on the activity of drug-metabolizing enzyme CYP450 and transporters.

MATERIALS AND METHODS

Human primary hepatocytes were used in present study. Probe substrates of CYP450 enzymes were incubated in human liver microsomes (HLMs) with and without SJP while IC₅₀ values were calculated. The inhibitory effect of SJP on the activity of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6 and 3A4 was evaluated. The inducing effect of SJP on the activity of CYP1A2, 2B6 and 3A4 was accessed. The inhibition of SJP on human OATP1B1 was investigated through cell-based assay. The inhibition of SJP on human MDR1 and BCRP was also estimated by means of the vesicles assay.

RESULTS

The results showed that the SJP under the concentration of 1000 μg/mL could inhibit the activity of CYP1A2, 2B6, 2C19, and 3A4, with IC₅₀ values of 189.7, 308.2, 331.2 and 805.7 μg/mL, respectively. There was no inhibitory effect found in the other 3 liver drug enzyme subtypes. In addition, SJP showed no induction effect on CYP1A2, 2B6 and 3A4, however it had a significant inhibitory effect on human-derived OATP1B1 at the concentration of 100 and 1000 μg/mL, with the IC₅₀ value of 21.9 μg/mL. Simultaneously, the SJP inhibited BCRP at high concentration of 1000 μg/mL but did not affect human MDR1.

CONCLUSIONS

Based on these research results above, it is suggested that the SJP can affect some of the CYP450 enzymes and transporters' activity. When used in combination with related conventional drugs, potential herb-drug interactions should be considered.

Effects of paeoniflorin on the activities and mRNA expression of rat CYP1A2, CYP2C11 and CYP3A1 enzymes in vivo

Paeoniflorin is the major constituent in extracts of the paeony root, the purpose of the present study was to assess the effects of paeoniflorin on the activities and mRNA expression of the rat hepatic drug-metabolizing enzymes cytochrome P450 (CYP1A2), CYP2C11 and CYP3A1 in vivo.Sprague-Dawley (SD) male rats were treated with paeoniflorin at the dosage of 25, 50 and 100 mg/kg or 0.9% sodium chloride solution by intragastric administration for 7 days, then were given probe drugs phenacetin (CYP1A2), tolbutamide (CYP2C11), or midazolam (CYP3A1) orally on the eighth day. Blood samples were collected at various times, and the plasma concentrations of the probe drugs were estimated with ultra-high-performance liquid chromatography. The mRNA expression levels of rat hepatic CYP1A2, CYP2C11 and CYP3A1 were analysed with real-time PCR.The pharmacokinetic results indicated that paeoniflorin inhibits the activities of CYP1A2, CYP2C11 and CYP3A1 in vivo. The effect was most pronounced on CYP3A1, according to the United States Food and Drug Administration classification of inhibitors of CYP3A, it reached the category of moderate inhibition. The mRNA expression levels of 3 CYP enzymes were also tended to be inhibited.We conclude that paeoniflorin can inhibit the activities of CYP1A2, CYP2C11 and CYP3A1 in vivo, which may affect the metabolism of drugs that are primarily dependent on these pathways.

The Protective Effect of Traditional Chinese Medicine on Liver Ischemia-Reperfusion Injury

Liver ischemia-reperfusion (I/R) injury occurs during transplantation and major hepatic surgery, which may lead to postoperative liver dysfunction. More and more traditional Chinese medicines (TCMs) have been used to treat liver ischemia-reperfusion injury. The purpose of this review is to evaluate the different protective effects of TCMs in the treatment of liver ischemia-reperfusion injury and to summarize its possible mechanisms. The results indicate that TCMs attenuate liver I/R injury via multiple mechanisms, including antioxidation stress, anti-inflammatory response, antiapoptosis, and inhibiting endoplasmic reticulum stress. However, the in-depth mechanism of the protective effects of these traditional Chinese medicines still remains unknown.

Chemical and sensory characterization of corn oil flavoured by citrus

Abstract A commercial and refined corn oil was added with fresh lemon and orange fruits to produce corn oil flavoured (COF), which were characterized for their quality parameters, fatty acid profile and concentrations of minor components. The sensory analysis was performed by a panel using the quantitative descriptive analysis and the hedonic score. Results showed that the addition of citrus fruits did not affect the oil quality indices, accomplishing the requirements for commercialization. The biophenols and pigments, initially absent in the refined oil, were detected in COF. The addition of orange or lemon fruits to the corn oil had no effects on oil stability, while the volatile profile in the headspace of flavoured oils showed the presence of several terpenes that were originally absent, among them: limonene; γ-terpinene; α-pinene and β-pinene. The sensory results confirmed that positive attributes and the acceptability of the unflavored corn oil can be improved by increasing amounts of both fruits.

Safety Evaluation of a New Traditional Chinese Medical Formula, Ciji-Hua'ai-Baosheng II Formula, in Adult Rodent Models

Background

Ciji-Hua'ai-Baosheng II Formula (CHB-II-F) is a new traditional Chinese medical formula that has been shown to reduce toxicity and side effects of chemotherapy and increase the probability of cancer patient survival. Whether CHB-II-F is safe as an adjunctive therapy for cancer patients receiving chemotherapy has yet to be determined.

Purpose

To evaluate the acute and subchronic toxic effects of CHB-II-F in rodent models.

Methods

In acute toxicity test, 24 Kunming mice were divided into 2 groups: untreated control and CHB-II-F 1.05 g/mL (31.44 g/kg) treated group. Treatment was administered to the treated group 3 times a day for 14 days. The overall health, adverse reactions, and mortality rate were documented. In subchronic toxicity test, 96 Sprague-Dawley rats were divided into 4 groups: untreated control, high dose CHB-II-F (H) (26.20 g/kg), medium dose CHB-II-F (M) (13. 10 g/kg), and low dose CHB-II-F (L) (6.55 g/kg) [equal to 24.375 g (dried medicinal herb)/kg] treated groups. Treated groups were given the treatments once a day for 4 weeks. The overall health and mortality rate were recorded every day. Body weight and food consumption were measured once a week. Hematologic and biochemical parameters, organ weights, and histopathologic markers were analyzed after 4 weeks. An additional 2 weeks were given as the treatment recovery period before end-point euthanization, and biochemical analyses were performed.

Results

The maximum tolerated dose (MTD) of CHB-II-F on mice was found to be 94.31 g/kg [equal to 351 g (dried medicinal herb)/kg], which is 108 times the human adult dose. In the acute toxicity test, administration of CHB-II-F 31.44 g/kg showed no adverse effect and did not cause mortality. In the subchronic toxicity test, after 4 weeks of treatment, compared to the controls, total cholesterol (TCHO) level, cardiac and splenic indexes, body weights of female rats, and mean corpuscular hemoglobin concentration (MCHC) in the CHB-II-F (H) group were significantly increased; triglyceride (TG) in the CHB-II-F (M) group and liver and splenic indexes in the CHB-II-F (L) group were increased. After the two-week recovery period, biofluid analyses, food consumption, and histopathologic examinations showed no abnormalities.

Conclusion

Administration of CHB-II-F had no obvious adverse effect on the overall health of rodent models. A daily maximum dose of less than 94.31 g/kg or 6.55 g/kg CHB-II-F for 4 continuous weeks was considered safe.

Rapid Authentication of Ginkgo biloba Herbal Products Using the Recombinase Polymerase Amplification Assay

Species adulteration in herbal products (HPs) exposes consumers to health risks. Chemical and morphological methods have their own deficiencies when dealing with the detection of species containing the same active compounds in HPs. In this study, we developed a rapid identification method using the recombinase polymerase amplification (RPA) assay to detect two species, Ginkgo biloba and Sophora japonica (as adulteration), in Ginkgo biloba HPs. Among 36 Ginkgo biloba HP samples, 34 were found to have Ginkgo biloba sequences, and 9 were found to have Sophora japonica sequences. During the authentication process, the RPA-LFS assay showed a higher specificity, sensitivity and efficiency than PCR-based methods. We initially applied the RPA-LSF technique to detect plant species in HPs, demonstrating that this assay can be developed into an efficient tool for the rapid on-site authentication of plant species in Ginkgo biloba HPs.

Dandelion root extract affects colorectal cancer proliferation and survival through the activation of multiple death signalling pathways

Dandelion extracts have been studied extensively in recent years for its anti-depressant and anti-inflammatory activity. Recent work from our lab, with in-vitro systems, shows the anti-cancer potential of an aqueous dandelion root extract (DRE) in several cancer cell models, with no toxicity to non-cancer cells. In this study, we examined the cancer cell-killing effectiveness of an aqueous DRE in colon cancer cell models. Aqueous DRE induced programmed cell death (PCD) selectively in > 95% of colon cancer cells, irrespective of their p53 status, by 48 hours of treatment. The anti-cancer efficacy of this extract was confirmed in in-vivo studies, as the oral administration of DRE retarded the growth of human colon xenograft models by more than 90%. We found the activation of multiple death pathways in cancer cells by DRE treatment, as revealed by gene expression analyses showing the expression of genes implicated in programmed cell death. Phytochemical analyses of the extract showed complex multi-component composition of the DRE, including some known bioactive phytochemicals such as α-amyrin, β-amyrin, lupeol and taraxasterol. This suggested that this natural extract could engage and effectively target multiple vulnerabilities of cancer cells. Therefore, DRE could be a non-toxic and effective anti-cancer alternative, instrumental for reducing the occurrence of cancer cells drug-resistance.

The role of dietary polyphenols in the management of erectile dysfunction-Mechanisms of action

The incidence of erectile dysfunction (ED) is on the increase and it is estimated that it will affect about 322 million men globally by the year 2025 if adequate measures are not taken to curb it. Natural polyphenols in plant based diets have gained public interest in recent times due to their roles in the prevention of various disease that implicate free radicals/reactive oxygen species and recently on ED. However, the role of polyphenols in the management of ED has not been explored due perhaps to limited data available. Hence this study which reviewed the role of dietary polyphenols in the management of ED and their mechanisms of action. Literature search was carried out in several electronic data bases such as Pubmed, Google Scholar, Medline, Agora and Hinari from1972 to 2016 to identify the current status of knowledge on the role of polyphenols in the management of erectile dysfunction. Progress made so far in this direction suggests inhibition of arginase, acetylcholinesterase, angiotensin converting enzyme, rho-kinase II; activation of endothelial and neuronal NO synthase; decreased synthesis of luteinizing hormone and testosterone reduction; activation of silent information regulator 2-related enzymes (sirtuin1) as well as free radical/reactive oxygen species inhibition as the mechanisms through which the polyphenols identified in this review exert beneficial roles in the management of ED.

Effects of salvianolic acid B and tanshinone IIA on the pharmacokinetics of losartan in rats by regulating the activities and expression of CYP3A4 and CYP2C9

Losartan (LST) is a common chemical drug used to treat high blood pressure and reduce the risk of stroke in certain people with heart disease. Danshen, prepared from the dried root and rhizome of Salvia miltiorrhiza Bunge, has been widely used for prevention and treatment of various cardiovascular and cerebrovascular diseases. There are more than 35 formulations containing Danshen indexed in the 2010 Chinese Pharmacopoeia, which are often combined with LST to treat cardiovascular and cerebrovascular diseases in the clinic. The effects of the two major components of Danshen, salvianolic acid B (SA-B) and tanshinone IIA (Tan IIA), on the pharmacokinetics of losartan and its metabolite, EXP3174, in rats were investigated by liquid chromatography coupled with mass spectrometry (LC-MS). Male Sprague-Dawley rats were randomly assigned to 3 groups: LST, LST+SA-B and LST+Tan IIA, and the main pharmacokinetic parameters were estimated after oral administration of LST, LST+SA-B and LST+Tan IIA. It was found that there are significant differences in the pharmacokinetic parameters among the three groups: Cmax, t1/2, AUC, AUMC in the LST+SA-B group was smaller than those in group LST, while larger in group LST+Tan IIA. Further, the effects of SA-B and Tan IIA on the metabolism of losartan was also investigated using rat liver microsomes in vitro. The results indicated that SA-B can induce the metabolism of LST, while Tan IIA can inhibit the metabolism of LST in rat liver microsomes in vitro by regulating activities of CYP450 enzymes. In addition, the effect of SA-B and Tan IIA on CYP3A4 and CYP2C9 expression was studied in Chang liver cells by western-blotting and Real-time PCR. It was concluded that the two components of Danshen, SA-B and Tan IIA have different influences on the metabolism of LST: SA-B can obviously speed up the metabolism of LST by inducing CYP3A4/CYP2C9 activities and expression, however, Tan IIA can slow down the metabolism of LST by inhibiting CYP3A4/CYP2C9 activities.

Quince peel polyphenolic extract blocks human colon adenocarcinoma LS174 cell growth and potentiates 5-fluorouracil efficacy

Background

Development of alternative cancer-specific drugs would be of paramount importance to overcome toxicity toward normal tissues and tumor resistance. Here, we investigated the potential anti-tumoral effect of peel (Peph) and pulp polyphenolic extracts from the Tunisian quince Cydonia oblonga Miller on both no-tumorigenic cells NIH 3T3 Fibroblasts and HEK 293 cells and human colon adenocarcinoma LS174 cells.

Methods

Cell proliferation and cytotoxicity were measured with MTT and LDH assays respectively. Cell cycle distribution and the apoptosis levels were assessed by flow cytometry. Intracellular reactive oxygen species (ROS) levels were determined using the fluorescent probe CM-H2DCFDA. Western blot was used to further characterize cell death and analyze the signaling pathways affected by Peph treatment. The expression level of VEGF-A was evaluated by real time quantitative PCR and further verified by quantifying the secreted cytokines by enzyme-linked immunosorbent assay.

Results

We found that Peph extract displayed the highest anti-proliferative effect specifically on LS174 cells. However, each Peph phenolic compound alone did not exhibit any anti-proliferative activity, suggesting a synergistic effect of phenolic molecules. Such effect was associated with a cell cycle arrest in the G1/S phase, a caspase-independent apoptosis and an increase of the ROS production. Peph extract inhibited the pro-survival signaling pathway NFκB and suppressed the expression of various cellular markers known to be involved in cell cycling (cyclin D1) and angiogenesis (Vascular Endothelial Growth Factor, VEGF). Interestingly, the combination Peph extract and 5-FU exerted synergistic inhibitory effect on cell viability.

Conclusion

These data propose the quince Peph extract as a promising cost effective non toxic drug to employ alone or in combination with conventional anti-colorectal cancer. Moreover, quince rich regimen may prevent the development and the progress of colon cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-016-0276-7) contains supplementary material, which is available to authorized users.

Research on the change of chemical composition in productive process of Re Du Ning injection by HPLC/Q-TOF MS

A high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC/Q-TOF MS) was developed for the analysis of chemical composition change in the production process of Re Du Ning injection, a Chinese medicine preparation with a combination of Lonicera japonica Thunb., Gardenia jasminoides Ellis and Artemisia annua L. A total of 90 compounds from raw materials-intermediates-Re Du Ning injection were detected; among them, 55 compounds were identified or tentatively characterized, and the characteristic ions of different types of compounds were described. Based on these studies, the different types of compounds in the various process routes were analyzed. A total of 28 compounds, including seven iridoid glycosides and six monoterpenes from G. jasminoides Ellis, five iridoid glycosides, nine phenolic acids and one unknown compound from L. japonica Thunb., were transferred to Re Du Ning injection, and two unknown compounds were generated in the production process of Re Du Ning injection. The results indicated that the Chinese Medicine Pharmaceutical process control is very important. This method could provide some reference for other Chinese medicine preparations.

Ethnic differences in medicinal plant use among University students: a cross-sectional survey of self-reported medicinal plant use at two Midwest Universities

BACKGROUND

Numerous surveys of medicinal plant use among college students abound, but none compare use between students enrolled in two different Universities with significantly different ethnic compositions. The objective of this study is to compare medicinal plant use between two different ethnic college populations and explore differences between student medicinal plant users and non-users for comparison with previous research.

METHODS

Students (n = 721) at a large research university (n = 498) and a Pan-Tribal University for Native Americans (n = 233) completed surveys in October 2011 to assess past year medicinal plant use. The Mann-Whitney U test, Chi Square test, and General Linear Model were used to compare demographics and self-reported use of medicinal plants among students at both Universities and between past year users and non-users.

RESULTS

Over 23% of university students surveyed reported past year medicinal plant use. Users were more likely to use commercial tobacco products and to report poorer health than non-users. While Native American student medicinal plant users reported significantly higher rates of commercial tobacco use, lower self-assessment of health, and less use of prescription medicine than non-Native users, no significant differences in prevalence of medicinal plant use were found between University student populations.

CONCLUSIONS

Results are consistent with preexisting data showing higher rates of medicinal plant use among college students compared to the larger US population of adults and demonstrate previously documented health disparities in Native American populations compared to non-Native Americans.

Common use of dietary supplements for bipolar disorder: a naturalistic, self-reported study

Background

Dietary supplements are taken by about half of Americans. Knowledge of dietary supplement use is important because they may interact with prescription drugs or other supplements, cause adverse reactions including psychiatric symptoms, or contain inherently toxic ingredients or contaminants. This study explores the use of dietary supplements by patients with bipolar disorder in the US.

Methods

Data were obtained from an ongoing, naturalistic study of patients with bipolar disorder who received pharmacological treatment as usual. The patients self-reported their daily mood, sleep, and medications taken, including all drugs prescribed for bipolar disorder or that the patient felt impacted their mood. These included other prescribed drugs, over-the-counter drugs and dietary supplements. Drugs that received premarketing approval from the FDA were not included as dietary supplements. Patient demographics and daily medication use were characterized.

Results

Data were available from 348 patients in the US who returned a mean 249.5 days of data. In addition to prescribed psychiatric drugs, 101 of the 348 patients (29 %) used a dietary supplement for at least 7 days and 69 (20 %) used a supplement long term (for at least 50 % of days). Of the 101 supplement users, 72 (71.3 %) took one supplement daily. The 101 patients tried over 40 different supplements, and the long-term users took 19 different supplements. The most commonly taken supplements for both groups were fish oil, B vitamins, melatonin, and multivitamins. Patients using supplements were more likely to be white (p < 0.001), older (p = 0.009), and ill for more years (p = 0.025).

Conclusions

Many patients with bipolar disorder use dietary supplements in addition to prescribed drugs. Physicians should obtain detailed information about all dietary supplements taken by patients with bipolar disorder.

Angelica sinensis (Umbelliferae) with proven repellent properties against Aedes aegypti, the primary dengue fever vector in Thailand

Botanical resources with great diversity in medicinal and aromatic plants are a rich and reliable source for finding insect repellents of plant origin, which are widely popular among today's consumers. Although some herbal-based repellents have been proven comparable to or even better than synthetics, commercially available natural repellents generally tend to be expensive, with short-lived effectiveness. This critical flaw leads to ongoing research for new and effective repellents, which provide longer protection against vector and nuisance-biting insects, while remaining safe, user friendly, and reasonably priced. This study aimed to evaluate the repellent activity of plant-derived products against the primary dengue vector, Aedes aegypti, by following the human bait technique of World Health Organization guidelines. Preliminary laboratory screening tests for repellency of 33 plant species clearly demonstrated Angelica sinensis as the most effective repellent from each kind of extracted product, with its essential oil and ethanolic extract having median complete protection times of 7.0 h (6.0-7.5) and 2.5 h (2.0-2.5), respectively. Due to its low yield (0.02 %), pungent smell, and little cause of irritation, A. sinensis essential oil did not qualify as a candidate for further repellent assessment. However, subsequent extractions of A. sinensis with different organic solvents of increasing polarity provided four extractants with varying degrees of repellency against A. aegypti. The hexane extract of A. sinensis provided excellent repellency, with a median complete protection time of 7.5 h (6.5-8.5), which was longer than that of ethanol (2.5, 2.0-2.5 h), acetone (1.75, 0.5-2.5 h), and methanol extracts (0.5, 0-1.0 h). By being the most effective product, A. sinensis hexane extract gave significant protection comparable to that of its essential oil and the standard synthetic repellent, N,N-diethyl-3-methylbenzamide (DEET: 6.25, 5.0-6.5 h). Qualitative gas chromatography/mass spectrometry analysis demonstrated the presence of phthalides and phthalates, including 3-N-butylphthalide, butylidenephthalide, ligustilide, and di-iso-octyl phthalate, as the principal constituents in A. sinensis products. The success of A. sinensis products, particularly that of hexane extract, has proved their potential as bioactive candidates in the next step for developing and producing alternative natural repellents with commercial aspirations.

Evaluation of the efficacy & biochemical mechanism of cell death induction by Piper longum extract selectively in in-vitro and in-vivo models of human cancer cells

Background

Currently chemotherapy is limited mostly to genotoxic drugs that are associated with severe side effects due to non-selective targeting of normal tissue. Natural products play a significant role in the development of most chemotherapeutic agents, with 74.8% of all available chemotherapy being derived from natural products.

Objective

To scientifically assess and validate the anticancer potential of an ethanolic extract of the fruit of the Long pepper (PLX), a plant of the piperaceae family that has been used in traditional medicine, especially Ayurveda and investigate the anticancer mechanism of action of PLX against cancer cells.

Materials & Methods

Following treatment with ethanolic long pepper extract, cell viability was assessed using a water-soluble tetrazolium salt; apoptosis induction was observed following nuclear staining by Hoechst, binding of annexin V to the externalized phosphatidyl serine and phase contrast microscopy. Image-based cytometry was used to detect the effect of long pepper extract on the production of reactive oxygen species and the dissipation of the mitochondrial membrane potential following Tetramethylrhodamine or 5,5,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolylcarbocyanine chloride staining (JC-1). Assessment of PLX in-vivo was carried out using Balb/C mice (toxicity) and CD-1 nu/nu immunocompromised mice (efficacy). HPLC analysis enabled detection of some primary compounds present within our long pepper extract.

Results

Our results indicated that an ethanolic long pepper extract selectively induces caspase-independent apoptosis in cancer cells, without affecting non-cancerous cells, by targeting the mitochondria, leading to dissipation of the mitochondrial membrane potential and increase in ROS production. Release of the AIF and endonuclease G from isolated mitochondria confirms the mitochondria as a potential target of long pepper. The efficacy of PLX in in-vivo studies indicates that oral administration is able to halt the growth of colon cancer tumors in immunocompromised mice, with no associated toxicity. These results demonstrate the potentially safe and non-toxic alternative that is long pepper extract for cancer therapy.

Identification and characterization of potent CYP2D6 inhibitors in lotus leaves

ETHNOPHARMACOLOGICAL RELEVANCE

The herb of lotus (Nelumbo nucifera) leaves is a commonly used traditional Chinese herbal medicine that is utilized for the treatment of sunstroke, to assuage thirst, and to cure both diarrhea and fever in China. Modern pharmacological studies have demonstrated that the herb exhibits various pharmacological effects, such as anti-hyperlipidemia, anti-obesity, anti-oxidant, anti-HIV, anti-microbial, and anti-hypoglycemic activities. Currently, the herb is becoming more popular in China as a "tea drink" or as a main ingredient of some herbal formulations, which implies that the herb and/or its products are now more likely to be concurrently administered with conventional medicines for losing body weight and reducing blood lipids. However, its potential inhibitory effect on human cytochrome P450 (CYP) has not been systemically investigated to date. The present study was performed to assess the potential inhibitory effects of lotus leaf alcoholic extract (LAE), its major fractions, and its main compounds on five CYP isoenzymes (CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4) in vitro.

MATERIAL AND METHODS

Five probe substrates were incubated with human liver microsomes in the presence or absence of the LAE, the alkaloid fraction (AF), the flavonoid fraction (FF), or the individual aporphine alkaloids, namely, nuciferine (NF), N-nornuciferine (N-NF), and 2-hydroxy-1-methoxyaporphine (HMA). After the incubation, the relative metabolites of the substrates were analyzed using LC-MS/MS.

RESULTS

The results showed that the LAE strongly inhibited CYP2D6 with an IC50 value of 12.05µg/mL and weakly inhibited other isoenzymes. In addition, FF was found to weakly inhibit CYP2D6, whereas AF exerted a markedly higher inhibitory effect on CYP2D6 activity with an IC50 value of 0.96µg/mL. The three aporphine alkaloids isolated from the AF (NF, N-NF, and HMA) significantly inhibited CYP2D6 with IC50 values of 3.78, 3.76, and 3.15µM, respectively. Their Lineweaver-Burk plots and Dixon plots showed that NF, N-NF, and HMA competitively inhibited CYP2D6 activity with Ki values of 1.88, 2.34, and 1.56µM, respectively.

CONCLUSION

The study revealed that the alkaloid compounds in lotus leaves exert a potent inhibitory effect on CYP2D6 isoenzyme. The possible drug interactions of the leaves and their preparations with conventional medicines should thus be taken into account.

Inhibition of baicalin on metabolism of phenacetin, a probe of CYP1A2, in human liver microsomes and in rats

Baicalin has been used as mainly bioactive constituent of about 100 kinds of traditional Chinese medicines in Chinese pharmacopoeia. The effect of baicalin on cytochrome P450 should be paid more attention because baicalin was used widely. The aim of this study was to investigate whether baicalin could inhibit CYP1A2 in pooled human liver microsomes (HLMs) and in rats in vivo and the gene polymorphisms could affect inter-individual variation in IC50 in 28 human livers. Phenacetin was used as probe of CYP1A2. Kinetic parameter of CYP1A2 and IC50 of baicalin on CYP1A2 to each sample were measured and the common CYP1A2 polymorphisms (-3860G>A and -163C>A) were genotyped. The results showed that baicalin exhibited a mixed-type inhibition in pooled HLMs, with a Ki value of 25.4 µM. There was substantial variation in Km, Vmax, CLint of CYP1A2 and IC50 of baicalin on CYP1A2 (3∼10-fold). The range was from 26.6 to 114.8 µM for Km, from 333 to 1330 pmol·min(-1)·mg(-1)protein for Vmax and from 3.8 to 45.3 µL·min(-1)·mg(-1) protein for CLint in HLMs (n = 28). The Mean (range) value of IC50 in 28 HLMs was 36.3 (18.9 to 56.1) µM. The genotypes of -3860G>A and -163C>A had no significant effect on the inhibition of baicalin on CYP1A2. The animal experiment results showed that baicalin (450 mg/kg, i.v.) significantly decreased the Cmax and CL of phenacetin, and increased C(60 min), t1/2, Vd and AUC (P<0.05). There were significant correlations between percentage of control in C(60 min), t1/2, CL, AUC of phenacetin and Cmax of baicalin in 11 rats (P<0.05). Protein binding experiments in vitro showed that baicalin (0-2000 mg/L) increased the unbound phenacetin from 14.5% to 28.3%. In conclusion, baicalin can inhibit the activity of CYP1A2 in HLMs and exhibit large inter-individual variation that has no relationship with gene polymorphism. Baicalin can change the pharmacokinetics of phenacetin in rats.

Dietary flavonoids modulate CYP2C to improve drug oral bioavailability and their qualitative/quantitative structure-activity relationship

This study aims to improve the drug oral bioavailability by co-administration with flavonoid inhibitors of the CYP2C isozyme and to establish qualitative and quantitative (QSAR) structure-activity relationships (SAR) between flavonoids and CYP2C. A total of 40 naturally occurring flavonoids were screened in vitro for CYP2C inhibition. Enzyme activity was determined by measuring conversion of tolbutamide to 4-hydroxytolbutamide by rat liver microsomes. The percent inhibition and IC50 of each flavonoid were calculated and used to develop SAR and QSAR. The most effective flavonoid was orally co-administered in vivo with a cholesterol-reducing drug, fluvastatin, which is normally metabolized by CYP2C. The most potent CYP2C inhibitor identified in vitro was tamarixetin (IC50 = 1.4 μM). This flavonoid enhanced the oral bioavailability of fluvastatin in vivo, producing a >2-fold increase in the area under the concentration-time curve and in the peak plasma concentration. SAR analysis indicated that the presence of a 2,3-double bond in the C ring, hydroxylation at positions 5, 6, and 7, and glycosylation had important effects on flavonoid-CYP2C interactions. These findings should prove useful for predicting the inhibition of CYP2C activity by other untested flavonoid-like compounds. In the present study, tamarixetin significantly inhibited CYP2C activity in vitro and in vivo. Thus, the use of tamarixetin could improve the therapeutic efficacy of drugs with low bioavailability.

Next revolution in the molecular theranostics of infectious diseases: microfabricated systems for personalized medicine

The molecular diagnosis of infectious diseases is currently going through a revolution sustained by the regulatory approval of amplification tests that have been shown to be equivalent or superior to existing gold standard methods. The recent approval of a microarray system for the pharmacogenomic profiling of cytochrome P450-mediated drug metabolism is paving the way to novel, rapid, sensitive, robust and economical microfabricated systems for point-of-care diagnostics, which are utilized closer and closer to the patient's bedside. These systems will enable the multiparametric genetic evaluation of several medical conditions, including infectious diseases. This forecoming revolution will position molecular theranostics in a broader integrated view of personalized medicine, which exploits genetic information from microbes and human hosts to optimize patient management and disease treatment.

Effects of aescin on cytochrome P450 enzymes in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Aescin, the main active component found in extracts of horse chestnut (Aesculus hippocastanum) seed a traditional medicinal herb, is a mixture of triterpene saponins. It has been shown to be effective in inflammatory, chronic venous and edematous treatment conditions in vitro and in vivo, and is broadly used to treat chronic venous insufficiency. The purpose of this study was to find out whether aescin influences the effect on rat cytochrome P450 (CYP) enzymes (CYP1A2, CYP2C9, CYP2E1 and CYP3A4) by using cocktail probe drugs in vivo; the influence on the levels of CYP mRNA was also studied.

MATERIALS AND METHODS

A cocktail solution at a dose of 5mL/kg, which contained phenacetin (20mg/kg), tolbutamide (5mg/kg), chlorzoxazone (20mg/kg) and midazolam (10mg/kg), was given as oral administration to rats treated with a single dose or multiple doses of intravenous aescin via the caudal vein. Blood samples were collected at a series of time-points and the concentrations of probe drugs in plasma were determined by HPLC-MS/MS. The corresponding pharmacokinetic parameters were calculated by the software of DAS 2.0. In addition, real-time RT-PCR was performed to determine the effects of aescin on the mRNA expression of CYP1A2, CYP2C9, CYP2E1 and CYP3A4 in rat liver.

RESULTS

Treatment with a single dose or multiple doses of aescin had inductive effects on rat CYP1A2, while CYP2C9 and CYP3A4 enzyme activities were inhibited. Moreover, aescin has no inductive or inhibitory effect on the activity of CYP2E1. The mRNA expression results were in accordance with the pharmacokinetic results.

CONCLUSIONS

Aescin can either inhibit or induce activities of CYP1A2, CYP2C9 and CYP3A4. Therefore, caution is needed when aescin is co-administration with some CYP1A2, CYP2C9 or CYP3A4 substrates in clinic, which may result in treatment failure and herb-drug interactions.

Herb–drug pharmacokinetic interaction of artificial calculus bovis with diclofenac sodium and chlorpheniramine maleate in rats

Objectives

To investigate the herb–drug pharmacokinetic interaction of artificial calculus bovis (ACB) with diclofenac sodium (DS) and chlorpheniramine maleate (CPM) in rats.

Methods

A sensitive high-performance liquid chromatography coupled with tandem mass spectrometry method was developed and validated for the simultaneous determination of DS and CPM in rat plasma. The proposed method was successfully applied to compare the herb–drug pharmacokinetic interaction of ACB with DS and CPM in rats following intragastric administration.

Key findings

The proposed method had good linearity and no endogenous material interfered with the analytes and internal standard peaks. The lower limit of quantification of DS and CPM was 1 and 0.1 ng/ml, respectively. There was no apparent pharmacokinetic interaction between DS and CPM. Co-administration of ACB with DS noticeably increased the area under the concentration–time curve (AUC0-∞) and peak plasma concentration (Cmax) of DS, while the parameters time of peak concentration (Tmax), clearance (ClZ/F) and apparent volume of distribution (VZ/F) of DS significantly decreased. Meanwhile, co-administration of ACB with CPM noticeably increased the Tmax, ClZ/F and VZ/F of CPM. A marked decline in AUC0-∞ and Cmax of CPM occurred in the presence of ACB.

Conclusions

This study indicated that co-administration of ACB with DS and CPM can result in an apparent herb–drug pharmacokinetic interaction in rats.

LC-MS/MS Identification of a Bromelain Peptide Biomarker from Ananas comosus Merr

Bromelain (Br) is a cysteine peptidase (GenBank AEH26024.1) from pineapple, with over 40 years of clinical use. The constituents mediating its anti-inflammatory activity are not thoroughly characterized and no peptide biomarker exists. Our objective is to characterize Br raw material and identify peptides in the plasma of Br treated mice. After SDS-PAGE in-gel digestion, Br (VN#3507; Middletown, CT, USA) peptides were analyzed via LC/MS/MS using 95% protein probability, 95% peptide probability, and a minimum peptide number = 5. Br spiked mouse plasma (1 ug/ul) and plasma from i.p. treated mice (12 mg/kg) were assessed using SRM. In Br raw material, we identified seven proteins: four proteases, one jacalin-like lectin, and two protease inhibitors. In Br spiked mouse plasma, six proteins (ananain, bromelain inhibitor, cysteine proteinase AN11, FB1035 precursor, FBSB precursor, and jacalin-like lectin) were identified. Using LC/MS/MS, we identified the unique peptide, DYGAVNEVK, derived from FB1035, in the plasma of i.p. Br treated mice. The spectral count of this peptide peaked at 6 hrs and was undetectable by 24 hrs. In this study, a novel Br peptide was identified in the plasma of treated mice for the first time. This Br peptide could serve as a biomarker to standardize the therapeutic dose and maximize clinical utility.

Selective induction of apoptosis and autophagy through treatment with dandelion root extract in human pancreatic cancer cells

OBJECTIVES

Pancreatic cancer has a 100% mortality rate; the aim of this study is to evaluate the efficacy of dandelion root extract (DRE) in inducing apoptosis and autophagy in aggressive and resistant pancreatic cancer cells.

METHODS

The effect of DRE was evaluated using WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate) assay. Apoptotic cell death was confirmed by nuclear condensation by Hoechst staining and externalization of phosphatidylserine to the outer leaflet of the plasma membrane by Annexin-V binding assay. Loss of mitochondrial membrane potential was observed using the JC-1 (5,5',6, 6'-tetrachloro-1,1',3,3' tetraethylbenzimidazolylcarbocyanine iodide) dye. The induction of autophagy was detected using a monodansylcadaverine assay and this was confirmed by immunofluorescence for light chain 3-II.

RESULTS

BxPC-3 and PANC-1 pancreatic cells were sensitive to aqueous DRE. This extract induces selective apoptosis in a dose- and time-dependent manner. Dandelion root extract caused the collapse of the mitochondrial membrane potential, leading to prodeath autophagy. Normal human fibroblasts were resistant at similar doses.

CONCLUSIONS

We demonstrate that DRE has the potential to induce apoptosis and autophagy in human pancreatic cancer cells with no significant effect on noncancerous cells. This will provide a basis on which further research in cancer treatment through DRE can be executed.

Evaluation of chinese-herbal-medicine-induced herb-drug interactions: focusing on organic anion transporter 1

The consumption of Chinese herbal medicines (CHMs) is increasing exponentially. Many patients utilize CHMs concomitantly with prescription drugs in great frequency. Herb-drug interaction has hence become an important focus of study. Transporter-mediated herb-drug interactions have the potential to seriously influence drug efficacy and toxicity. Since organic anion transporter 1 (OAT1) is crucial in renal active secretion and drug-drug interactions, the possibility of modulation of OAT1-mediated drug transport should be seriously concerned. Sixty-three clinically used CHMs were evaluated in the study. An hOAT1-overexpressing cell line was used for the in vitro CHMs screening, and the effective candidates were administered to Wistar rats to access renal hemodynamics. The regulation of OAT1 mRNA expression was also examined for further evidence of CHMs affecting OAT1-mediated transport. Among all the 63 CHMs, formulae Gui Zhi Fu Ling Wan (GZ) and Chia Wei Hsiao Yao San (CW) exhibited significant inhibitions on hOAT1-mediated [³H]-PAH uptake in vitro and PAH clearance and net secretion in vivo. Moreover, GZ showed concentration-dependent manners both in vitro and in vivo, and the decrease of rOAT1 mRNA expression indicated that GZ not only inhibited function of OAT1 but also suppressed expression of OAT1.

Natural Health Product Utilization in Warfarinized Children; Prevalence and Knowledge

Background:

The need for long-term thromboprophylaxis in children using warfarin therapy is increasing. Natural health products (NHPs) are administered to children by parents who perceive them to be useful and acceptable adjuncts or alternatives to conventional therapies. Interactions of NHPs with prescribed therapies may result in serious adverse events. NHP usage is underevaluated in children and there are no studies evaluating NHP usage in warfarinized children.

Objectives:

To explore NHP use in warfarinized children and their siblings to determine the prevalence, varieties, and reasons for NHP usage, as well as the potential effect on warfarinization (eg, time in therapeutic range [TTR]).

Methods:

This is a 3-phase cross-sectional cohort study that includes the (1) prevalence (2) NHP education and knowledge assessment, and (3) the follow-up NHP utilization phase.

Results:

Forty-six percent of warfarinized children consumed NHPs, with time in therapeutic range of 74%. The mean score for baseline knowledge of NHPs and warfarin following the education phase was 67%. Follow-up NHP use was 30%, and increased consistency of utilization with TTR was 83% (p < 0.05), consistent with education provided.

Conclusions:

The consistent prevalence rates over time of NHP usage in warfarinized children indicate the need for future studies. Education remains vital to combat the potential risks of NHP-warfarin interaction, encouraging patient disclosure and consistency.

Effects of Radix Astragali and Radix Rehmanniae, the components of an anti-diabetic foot ulcer herbal formula, on metabolism of model CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4 probe substrates in pooled human liver microsomes and specific CYP isoforms

The present study investigated the effects of Radix Astragali (RA) and Radix Rehmanniae (RR), the major components of an anti-diabetic foot ulcer herbal formula (NF3), on the metabolism of model probe substrates of human CYP isoforms, CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4, which are important in the metabolism of a variety of xenobiotics. The effects of RA or RR on human CYP1A2 (phenacetin O-deethylase), CYP2C9 (tolbutamide 4-hydroxylase), CYP2D6 (dextromethorphan O-demethylase), CYP2E1 (chlorzoxazone 6-hydroxylase) and CYP3A4 (testosterone 6β-hydroxylase) activities were investigated using pooled human liver microsomes. NF3 competitively inhibited activities of CYP2C9 (IC(50)=0.98mg/ml) and CYP3A4 (IC(50)=0.76mg/ml), with K(i) of 0.67 and 1.0mg/ml, respectively. With specific human CYP2C9 and CYP3A4 isoforms, NF3 competitively inhibited activities of CYP2C9 (IC(50)=0.86mg/ml) and CYP3A4 (IC(50)=0.88mg/ml), with K(i) of 0.57 and 1.6mg/ml, respectively. Studies on RA or RR individually showed that RR was more important in the metabolic interaction with the model CYP probe substrates. RR dose-dependently inhibited the testosterone 6β-hydroxylation (K(i)=0.33mg/ml) while RA showed only minimal metabolic interaction potential with the model CYP probe substrates studied. This study showed that RR and the NF3 formula are metabolized mainly by CYP2C9 and/or CYP3A4, but weakly by CYP1A2, CYP2D6 and CYP2E1. The relatively high K(i) values of NF3 (for CYP2C9 and CYP3A4 metabolism) and RR (for CYP3A4 metabolism) would suggest a low potential for NF3 to cause herb-drug interaction involving these CYP isoforms.

Polysaccharide peptides from Coriolus versicolor competitively inhibit model cytochrome P450 enzyme probe substrates metabolism in human liver microsomes

Polysaccharide peptide (PSP), isolated from COV-1 strain of Coriolus versicolor, is commonly used as an adjunct in cancer chemotherapy or health supplement in China. Previous studies have shown that PSP decreased antipyrine clearance and inhibited rat CYP2C11-mediated tolbutamide 4-hydroxylation and in human CYP2C9. In this study, the effects of the water extractable fraction of PSP on the metabolism of model CYP1A2, CYP2D6, CYP2E1 and CYP3A4 probe substrates were investigated in pooled human liver microsomes. PSP (1.25-20μM) dose-dependently decreased CYP1A2-mediated metabolism of phenacetin to paracetamol (IC(50) 19.7μM) and CYP3A4-mediated metabolism of testosterone to 6β-hydroxytestosterone (IC(20) 7.06μM). Enzyme kinetics studies showed the inhibition of CYP1A2 activity was competitive and concentration-dependent (K(i)=18.4μM). Inhibition of testosterone to 6β-hydroxytestosterone was also competitive and concentration-dependent (K(i)=31.8μM). Metabolism of dextromethorphan to dextrorphan (CYP2D6-mediated) and chlorzoxazone to 6-hydroxychlorzoxazone (CYP2E1-mediated) was only minimally inhibited by PSP, with IC(20) values at 15.6μM and 11.9μM, respectively. This study demonstrated that PSP competitively inhibited the CYP1A2- and CYP3A4-mediated metabolism of model probe substrates in human liver microsomes in vitro. The relatively high K(i) values for CYP1A2 and CYP3A4 would suggest a low potential for PSP to cause herb-drug interaction related to these CYP isoforms.

Investigation of cytochrome P450 1A2 and 3A inhibitory properties of Danshen tincture

Danshen (Salvia miltiorrhiza Bunge) as a famous Traditional Chinese medicine is widely used in the treatment of cardiovascular and cerebrovascular diseases in the world. Danshen tincture (DT), extracted from Danshen root with a mixture of water and alcohol, is a commonly used preparation method for human consumption. The aim of this study was to investigate the effects of DT on the cytochrome P450 (CYP) 1A2 and 3A activities by human and rat liver microsomes. Effects of DT were assessed with use of Danshen ethanolic extract (DEE) and selective substrates, markers of CYP activities. DEE (0.5-10 μg/ml) competitively inhibited human and rat liver microsomal CYP1A2 activity with inhibition constant (K(i)) values at 3.40 and 5.16 μg/ml, respectively. At the same time, DEE (2.5-20 μg/ml) not only noncompetitively inhibited human liver microsomal CYP3A4/5 activity with a K(i) of 11.9 μg/ml, but also competitively inhibited rat liver microsomal CYP3A1/2 activity with a K(i) of 52.1 μg/ml. The data indicate that DEE inhibited the metabolism of CYP1A2 and 3A substrates in human and rat liver in vitro with different mode of inhibition. This study may be helpful for clinical application of Danshen tincture.

The effect of garlic supplements and phytochemicals on the ADMET properties of drugs

INTRODUCTION

Garlic supplements have received wide public attention because of their health-beneficial effects. Although these products are considered as innocuous, several case reports and studies have shown the capacity of individual garlic phytochemicals/supplements to interfere with drug pharmacokinetics.

AREAS COVERED

This review covers recently published literature on garlic chemistry and composition, and provides a thorough review of published studies evaluating drug-garlic interactions. The authors illustrate the mechanisms underlying pharmacokinetic interactions, which could serve as important highlights in further research to explain results for drugs with narrow therapeutic indices or for drugs, utilizing multiple absorption, distribution and metabolism pathways.

EXPERT OPINION

To increase the relevance of further research on safety and efficacy of garlic supplements and phytochemicals, their composition should be addressed before conducting in vitro or in vivo research. It is also strongly recommended to characterize in vitro formulation performance to assess the rate and extent of garlic phytochemical release in order to anticipate the in vivo impact on the pharmacokinetics of concomitantly consumed drugs. The main conclusion of this review is that the impact of garlic on different stages of pharmacokinetics, especially on drug absorption and metabolism, is drug specific and dependent on the type/quality of utilized supplement.

Tanshinone I increases CYP1A2 protein expression and enzyme activity in primary rat hepatocytes

This study investigated the effects of Danshen and its active ingredients on the protein expression and enzymatic activity of CYP1A2 in primary rat hepatocytes. The ethanolic extract of Danshen roots (containing mainly tanshinones) inhibited CYP1A2-catalyzed phenacetin O-deethylation (IC(50)=24.6 μg/ml) in primary rat hepatocytes while the water extract containing mainly salvianolic acid B and danshenshu had no effect. Individual tanshinones such as cryptotanshinone, dihydrotanshinone, tanshinone IIA inhibited the CYP1A2-mediated metabolism with IC(50) values at 12.9, 17.4 and 31.9 μM, respectively. After 4-day treatment of the rat hepatocytes, the ethanolic extract of Danshen and tanshinone I increased rat CYP1A2 activity by 6.8- and 5.2-fold, respectively, with a concomitant up-regulation of CYP1A2 protein level by 13.5- and 6.5-fold, respectively. CYP1A2 induction correlated with the up-regulation of mRNA level of aryl hydrocarbon receptor (AhR), which suggested a positive feedback mechanism of tanshinone I-mediated CYP1A2 induction. A formulated Danshen pill (containing mainly danshensu and salvianolic acid B and the tanshinones) up-regulated CYP1A2 protein expression and enzyme activity, but danshensu and salvianolic acid B, when used individually, did not affect CYP1A2 activity. This study was the first report on the Janus action of the tanshinones on rat CYP1A2 activity.

Polysaccharide peptides from Coriolus versicolor competitively inhibit tolbutamide 4-hydroxylation in specific human CYP2C9 isoform and pooled human liver microsomes

Polysaccharide peptide (PSP), isolated from COV-1 strain of Coriolus versicolor, is commonly used as an adjunct in cancer chemotherapy in China. Previous studies have shown that PSP decreased antipyrine clearance and inhibited CYP2C11-mediated tolbutamide 4-hydroxylation in the rat both in vitro and in vivo. In this study, the effects of water extractable fraction of PSP on tolbutamide 4-hydroxylation was investigated in pooled human liver microsomes and in specific human CYP2C9 isoform. PSP (2.5-20μM) dose-dependently decreased the biotransformation of tolbutamide to 4-hydroxy-tolbutamide. Enzyme kinetics studies showed inhibition of tolbutamide 4-hydroxylase activity was competitive and concentration-dependent. In pooled human liver microsomes, PSP had a K(i) value of 14.2μM compared to sulfaphenazole, a human CYP2C9 inhibitor, showed a K(i) value of 0.32μM. In human CYP2C9 isoform, the K(i) value of PSP was 29.5μM and the K(i) value of sulfaphenazole was 0.04μM. This study demonstrated that PSP can competitively inhibit tolbutamide 4-hydroxylation in both pooled human liver microsomes and specific human CYP2C9 in vitro. This study compliments previous findings in the rat that PSP can inhibit human tolbutamide 4-hydroxylase, but the relatively high K(i) values in human CYP2C9 would suggest a low potential for PSP to cause herb-drug interaction.

Cree antidiabetic plant extracts display mechanism-based inactivation of CYP3A4

Seventeen Cree antidiabetic medicinal plants were studied to determine their potential to inhibit cytochrome P450 3A4 (CYP3A4) through mechanism-based inactivation (MBI). The ethanolic extracts of the medicinal plants were studied for their inhibition of CYP3A4 using the substrates testosterone and dibenzylfluorescein (DBF) in high pressure liquid chromatography (HPLC) and microtiter fluorometric assays, respectively. Using testosterone as a substrate, extracts of Alnus incana , Sarracenia purpurea , and Lycopodium clavatum were identified as potent CYP3A4 MBIs, while those from Abies balsamea , Picea mariana , Pinus banksiana , Rhododendron tomentosum , Kalmia angustifolia , and Picea glauca were identified as less potent inactivators. Not unexpectedly, the other substrate, DBF, showed a different profile of inhibition. Only A. balsamea was identified as a CYP3A4 MBI using DBF. Abies balsamea displayed both NADPH- and time-dependence of CYP3A4 inhibition using both substrates. Overall, several of the medicinal plants may markedly deplete CYP3A4 through MBI and, consequently, decrease the metabolism of CYP3A4 substrates including numerous medications used by diabetics.

Herb-drug pharmacokinetic interactions reviewed

IMPORTANCE OF THE FIELD

the global increase in the popularity of alternative medicines has raised renewed concerns regarding herb-drug interactions. These interactions are especially important for drugs with narrow therapeutic indices and may either be pharmacodynamic or pharmacokinetic in nature.

AREAS COVERED IN THIS REVIEW

pharmacokinetic interactions which may exist between herbs and drugs, and the mechanisms of these interactions with appropriate examples based on primary and secondary data in publications are discussed. The mechanisms covered include those that affect oral drug absorption (e.g., modulation of efflux and uptake transporters, complex formation, gastrointestinal motility and pH) and drug biotransformation (e.g., inhibition or induction of enzymes).

WHAT THE READER WILL GAIN

knowledge on the mechanisms of herb-drug pharmacokinetic interactions supported by an extended list of these types of interactions for quick reference. A critical evaluation of certain herb-drug pharmacokinetic interactions reported in the scientific literature.

TAKE HOME MESSAGE

as the incidence and severity of herb-drug pharmacokinetic interactions increase due to a worldwide rise in the use of herbal preparations, more clinical data regarding herb-drug pharmacokinetic interactions are needed to make informed decisions regarding patient safety.

HIV protease inhibitors: garlic supplements and first-pass intestinal metabolism impact on the therapeutic efficacy

BACKGROUND/AIMS

The aim of this study was to elucidate the impact of first-pass intestinal metabolism to therapeutic efficacy of antiretrovirals and to ascertain interaction mechanisms between garlic supplements (aged garlic extract) and HIV-protease inhibitors.

METHODS

In vitro permeability through rat jejunum, Caco-2 cell monolayers was determined and CYP3A4 metabolism studies were performed.

RESULTS

Saquinavir and darunavir efflux from enterocytes into gastrointestinal lumen significantly increased in the presence of aged garlic extract, whereas their CYP3A4 metabolism was inhibited. In the case of saquinavir a significant increase of its efflux was observed also in the presence of lower ritonavir doses. Because both drugs bound to different binding sites on P-glycoprotein and/or multidrug resistance associated protein 2 than garlic phytochemicals or ritonavir, lower amounts of antiretrovirals were absorbed.

CONCLUSIONS

The fractions of tested anti-HIV drugs absorbed could decrease significantly during self-medication with garlic supplements or ritonavir dose adjustments. Due to distinct saquinavir and darunavir preferences for binding sites on efflux transporters, the presence of other compounds (garlic phytochemicals, ritonavir), capable of influencing intestinal transporter-enzyme interplay, might lead to pharmacokinetic interactions observed in clinical studies and case reports with anti-HIV drugs.

Effects of the aqueous extract from Salvia miltiorrhiza Bunge on caffeine pharmacokinetics and liver microsomal CYP1A2 activity in humans and rats

Objectives

The effects of the aqueous extract of Salvia miltiorrhiza Bunge (Danshen) on metabolism/pharmacokinetics of caffeine and on liver microsomal CYP1A2 activity in humans and rats have been investigated.

Methods

The effects of Danshen aqueous extract on CYP1A2 activity were determined by metabolism of model substrates in the rat in vivo and in humans and rats in vitro. HPLC was used to determine model substrates and metabolites.

Key findings

In the rat, single dose Danshen aqueous extract treatment (100 or 200 mg/kg, i.p.) decreased metabolism of caffeine to paraxanthine, with overall decrease in caffeine clearance (6–20%), increase in area under the curve (AUC; 7–24%) and plasma half-life (t½ 14–16%). Fourteen-day Danshen aqueous extract treatment (100 mg/kg/day, i.p. or 200 mg/kg/day, p.o.) decreased caffeine clearance (16–26%), increased AUC (18–31%) and prolonged plasma t½ (8–10%). Aqueous extract of Danshen (125–2000 µg/ml) competitively inhibited human and rat liver microsomal CYP1A2 activity with inhibition constant (Ki) values at 190 and 360 µg/ml, respectively.

Conclusions

These studies demonstrated that Danshen aqueous extract affected the metabolism of CYP1A2 substrates through competitive inhibition and altered their clearance.

Public safety and dietary supplementation

Approximately 6 in 10 Americans report regularly using some type of dietary supplement, and approximately 1 in 6 Americans reports using herbal remedies on a regular basis. The diversity of manufacturers, manufacturing processes, and quality control issues are enormous. As with all plant products, herbal products are complex mixtures of a variety of chemical constituents with considerable variation in the growth, harvesting, and storage conditions, including different extraction procedures. Furthermore, not only is there variation in batches, but also the potential for contamination. In addition, herbal products have the potential to interact with pharmaceuticals. These problems have led to consumer and physician confusion about the use of herbal products and have not been satisfactorily resolved, because the Food and Drug Administration has only very recently started to fulfill its mission of consumer protection in the realm of dietary supplements. More importantly, we provide a working plan for addressing this important issue.

In vitro inhibitory effect of West African medicinal and food plants on human cytochrome P450 3A subfamily

AIM OF THE STUDY

In Africa, medicinal plants are used intensively and concomitantly with allopathic medicines in the treatment of opportunity diseases by many patients or by healthy person to prevent diseases. However, there is little information about the interactions between medicines and botanical products used currently in West Africa area. Therefore, the aim of the present investigation is to study the effect of some plant products on CYP3A4, CYP3A5 and CYP3A7, three individual enzymes of CYP3A subfamily, in vitro.

MATERIALS AND METHODS

Teas and ethanolic extracts of medicinal, food and co-administered plants were evaluated on CYP3A4, CYP3A5 and CYP3A7 individual enzymes in vitro using fluorometric assays.

RESULTS

Extracts of adjuvant plants such as Aframomum cuspidatum, and Aframomum melegueta, as well as one medicinal plant (Harrisonia abyssinica) inhibited CYP3A4, CYP3A5 and CYP3A7 activity more than 90%. Phyllanthus amarus showed high inhibition of CYP3A5 and CYP3A7. Food plants (Solanum macrocarpon and Talinum triangulare) inhibited CYP3A4 and CYP3A5 less than 20%.

CONCLUSION

These results indicate that plants tested in this study affect in vitro the activity of the main three CYP3A subfamily enzymes. These active plants could interfere with the metabolism at phase I of conventional drugs in vivo as well act as pharmacoenhancers in herbal mixtures.