Clinical and laboratory investigations in herbal poisonings

Oleuropein-Induced Acceleration of Cytochrome P450-Catalyzed Drug Metabolism: Central Role for Nuclear Receptor Peroxisome Proliferator-Activated Receptor α

Oleuropein (OLE), the main constituent of Olea europaea, displays pleiotropic beneficial effects in health and disease, which are mainly attributed to its anti-inflammatory and cardioprotective properties. Several food supplements and herbal medicines contain OLE and are available without a prescription. This study investigated the effects of OLE on the main cytochrome P450s (P450s) catalyzing the metabolism of many prescribed drugs. Emphasis was given to the role of peroxisome proliferator-activated receptor α (PPARα), a nuclear transcription factor regulating numerous genes including P450s. 129/Sv wild-type and Ppara-null mice were treated with OLE for 6 weeks. OLE induced Cyp1a1, Cyp1a2, Cyp1b1, Cyp3a14, Cyp3a25, Cyp2c29, Cyp2c44, Cyp2d22, and Cyp2e1 mRNAs in liver of wild-type mice, whereas no similar effects were observed in Ppara-null mice, indicating that the OLE-induced effect on these P450s is mediated by PPARα. Activation of the pathways related to phosphoinositide 3-kinase/protein kinase B (AKT)/forkhead box protein O1, c-Jun N-terminal kinase, AKT/p70, and extracellular signal-regulated kinase participates in P450 induction by OLE. These data indicate that consumption of herbal medicines and food supplements containing OLE could accelerate the metabolism of drug substrates of the above-mentioned P450s, thus reducing their efficacy and the outcome of pharmacotherapy. Therefore, OLE-induced activation of PPARα could modify the effects of drugs due to their increased metabolism and clearance, which should be taken into account when consuming OLE-containing products with certain drugs, in particular those of narrow therapeutic window. SIGNIFICANCE STATEMENT: This study indicated that oleuropein, which belongs to the main constituents of the leaves and olive drupes of Olea europaea, induces the synthesis of the major cytochrome P450s (P450s) metabolizing the majority of prescribed drugs via activation of peroxisome proliferator-activated receptor α. This effect could modify the pharmacokinetic profile of co-administered drug substrates of the P450s, thus altering their therapeutic efficacy and toxicity.

Mercury based drug in ancient India: The red sulfide of mercury in nanoscale

Mercury is one of the elements which had attracted the attention of the chemists and physicians of ancient India and China. Among the various metal based drugs which utilize mercury, we became interested in the red sulfide of mercury which is known in ancient Indian literature as rasasindur (alias rasasindura, rasasindoor, rasasinduram, sindur, or sindoor) and is used extensively in various ailments and diseases. Following various physico-chemical characterizations it is concluded that rasasindur is chemically pure α-HgS with Hg:S ratio as 1:1. Analysis of rasasindur vide Transmission Electron Microscopy (TEM) showed that the particles are in nanoscale. Bio-chemical studies of rasasindur were also demonstrated. It interacts with Bovine Serum Albumin (BSA) with an association constant of (9.76 ± 0.56) × 10³ M⁻¹ and behaves as a protease inhibitor by inhibiting the proteolysis of BSA by trypsin. It also showed mild antioxidant properties.

Method development for the determination of elements in Hypericum perforatum L. (St John's wort) herb and preparations using inductively coupled plasma–optical emission spectroscopy and microwave digestion

Objectives

A method was developed to analyze St John's wort (Hypericum perforatum L.) herb and preparations using inductively coupled plasma–optical emission spectroscopy (ICP-OES) to determine the quantity of 11 elements (Al, B, Ba, Ca, Cu, Fe, Mg, Mn, Ni, Sr and Zn).

Methods

This study includes the evaluation of digestion acids and calibration methods, as well as instrumental parameters such as choice of nebulizer and emission wavelength.

Key findings

Two nebulizers (Conikal and SeaSpray) performed similarly for most elements, and two optimum wavelengths were determined for each element. Five acids were evaluated for the digestion of the Polish Certified Reference Material Tea Leaves (INCT-TL-1), while three were taken forward to use for the different St John's wort formulations (i.e. herb, capsule and tablet). A simple protocol using 5 ml HNO3 was sufficient in most cases; however, variability was observed for elements often bound in silicates (e.g. Al, Fe and Zn). An external weighted calibration was also found to be preferential over unweighted, and the use of standard addition affected some concentration values up to 20%.

Conclusions

Therefore, this paper presents the development and optimized method parameters to be used with ICP-OES that will allow the analysis of 11 key elements present in St John's wort herb and preparations.

Elemental fingerprinting of Hypericum perforatum (St John's Wort) herb and preparations using ICP-OES and chemometrics

St. John's wort (SJW) (Hypericum perforatum) is a herbal remedy commonly used to treat mild depression. The elemental profiles of 54 samples (i.e., dry herbs, tablets and capsules) were evaluated by monitoring 25 elements using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The major elemental constituents in the SJW samples were Ca (300-199,000μg/g), Mg (410-3,530μg/g), Al (4.4-900μg/g), Fe (1.154-760μg/g), Mn (2.4-261μg/g), Sr (0.88-83.6μg/g), and Zn (7-64μg/g). For the sixteen elements that could be reliably quantified, principal component analysis (PCA) was used to investigate underlying patterns in the data. PCA models identified 7 key elements (i.e., Ba, Ca, Cd, Mg, Mo, Ni and Y), which described 85% of the variance in the dataset in the first three principal components. The PCA approach resulted in a general delineation between the three different formulations and provides a basis for monitoring product quality in this manner.

Identification and determination of synthetic pharmaceuticals as adulterants in eight common herbal weight loss supplements

Background:

Adulterated herbal weight loss products with containing undeclared synthetic drugs are common and responsible for many serious health damages.

Objectives:

The purpose of the study was to determine five synthetic adulterants in eight common herbal weight loss supplements, which are currently sold in Iran markets, to verify their presence in supplements, without mentioning on the labels.

Materials and Methods:

Eight common herbal weight loss samples were obtained from the Iran pharmaceutical market after advertising in the Persian language on satellite channels and internet. Five pharmacological classes of drugs used for weight loss, namely sibutramine, phenolphthalein, phenytoin, bumetanide and rimonabant, were investigated and quantified by GC-MS for the first three and LC-MS for the last two medications.

Results:

The most undeclared ingredients, which were illegally added include sibutramine, phenolphthalein, bumetanide, and phenytoin in the original super slim, herbaceous essence, super slim green lean, and fat loss, supplements, respectively. Rimonabant was not found. Caffeine, pseudoephedrine, theobromine and amfepramone were also found in the supplements using GC-MS assay.

Conclusions:

Adulterated synthetic substances were detected in the herbal weight loss products. Health care professionals should make people aware of the risks of taking herbal weight-loss supplements.

Cyclamen Trochopteranthum: Cytotoxic activity and possible adverse interactions including drugs and carcinogens

OBJECTIVE: To examine the effect of water extracts of cyclamen tubers on the expression of main cytochrome P450 (CYP450s) including CYP1A1, CYP1A2 CYP2E1, CYP2B6, CYP2C9 and CYP3A4 that participate in the metabolism of both drugs and carcinogens and cytotoxic activity in human cancer cell lines, namely HepG2 and Caco-2. METHODS: Cyclamen trochopteranthum tubers were extracted with dH(2)O and then lyophilized under vacuum. Infrared spectral study was made for extracts by Fourier transform infrared spectroscopy (FT-IR). Cytotoxic activity of cyclamen was determined by crystal violet staining in HepG2 and Caco-2 cells. CYP expression was determined by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Cyclamen water extract had moderate cytotoxic activity. It was found that lethal concentration (LC50) value of the cyclamen extract was 50 and 125 μg/mL in HepG2 and Caco-2 cell lines, respectively. Moreover, it caused induction and suppression of CYP450s mRNA levels in HepG2 and Caco-2 cells. CONCLUSION: Cyclamen may have a potential not only inhibition and/or induction of the metabolism of certain co-administered drugs but also development of toxicity, mutagenesis and malignant transformation due to induction or suppression of the CYP450s dependent drug metabolizing enzymes.

Sulfur fumigation processing of traditional chinese medicinal herbs: beneficial or detrimental?

Majority of traditional Chinese medicine (TCM) herbs need to undergo post-harvesting processing to convert raw material into the form readily used for prescription. In general, processing procedures are either according to China Pharmacopeia or based on traditional methods. Recently sulfur fumigation is increasingly used to replace traditional sun-drying for its pesticidal and anti-bacterial properties in a cheap and convenient manner. However, to date information on effects of sulfur fumigation on herbal safety and efficacy are limited. This article addresses potential destructive effects of sulfur fumigation on herbal efficacy and safety through reviewing currently available information. Since recently increased numbers of studies have demonstrated that sulfur fumigation-induced dramatic changes in chemical profiles of various sulfur-fumigated herbs, consequent alteration of efficacy, and/or potential incidence of toxicity are suspected. Therefore comprehensive investigations on effects of sulfur fumigation on toxicity, chemical profiles, pharmacokinetics, and bioactivities of TCM herbs are timely to provide scientific basis for standardization and regulation of this currently common but potentially harmful processing method.

Interaction of natural products with cell survival and signaling pathways in the biochemical elucidation of drug targets in cancer

The use of natural products with therapeutic properties is as ancient as human civilization and for a long time mineral, plant and animal products were the main sources of drugs. Worldwide sales of medicinal plants, crude extracts and finished products amounted to US$15 billion in 1999 and it increased to $23 billion in 2002. More interestingly, the influence of natural products upon anticancer drug discovery and design cannot be underestimated. Approximately 60% of all drugs in clinical trials are either a natural product, compounds derived from natural products or contain pharmacophores derived from active natural products. Thus, even today, in the presence of massive numbers of agents from combinatorial libraries, compounds from natural sources are still in the forefront of cancer chemotherapeutics as sources of active drug types, as well as being involved in drug discovery in diseases such as microbial and parasitic infections and the control of cholesterol/lipids, among other functions.

Quality control of plant food supplements

It is essential to guarantee the safety of unprocessed plants and food supplements if consumers' health is to be protected. Although botanicals and their preparations are regulated at EU level, at least in part, there is still considerable discretion at national level, and Member States may choose to classify a product either as a food supplement or as a drug. Accurate data concerning the finished products and the plant used as the starting point are of major importance if risks and safety are to be properly assessed, but in addition standardized criteria for herbal preparation must be laid down and respected by researchers and manufacturers. Physiologically active as well as potentially toxic constituents need to be identified, and suitable analytical methods for their measurement specified, particularly in view of the increasing incidence of economically motivated adulteration of herbal raw materials and extracts. It remains the duty of food operators to keep up with the scientific literature and to provide sufficient information to enable the adaptation of specifications, sampling schemes and analytical methods to a fast-changing environment.

Effects of Cyclamen trochopteranthum on hepatic drug-metabolizing enzymes

The modulatory effects of the Cyclamen trochopterantum tuber extract on hepatic drug-metabolizing enzymes, including aniline 4-hydroxylase (A4H; CYP2E1), ethoxyresorufin O-deethylase (EROD; CYP1A), methoxyresorufin O-demethylase (MROD; CYP1A), caffeine N-demethylase (C3ND; CYP1A2) aminopyrene N-demethylase (APND; CYP2C6), and erythromycin N-demethylase (ERND; CYP3A1), were examined in vivo in rats. The activities of all of these enzymes were induced by the cyclamen extract. In addition, Western-blot and RT-PCR results clearly showed that CYP2E1, CYP1A1/CYP1A2 and CYP2C6 protein and mRNA levels were substantially increased by four different doses of cyclamen. Although, the CYP3A1 protein level was increased significantly, the mRNA level was not changed. These results indicate that cyclamen tuber extract might have a potential not only to inhibit and/or induce the metabolism of certain co-administered drugs but also influence the development of toxicity and carcinogenesis due to the induction of the cytochrome P450-dependent drug-metabolizing enzymes.

Respiratory failure in a neonate after folk treatment with broom bush (Retama raetam) extract

OBJECTIVES

To increase the awareness of intoxication by folk herbal remedies in the pediatric population.

METHODS

Case report of a 7-day-old baby boy admitted to a pediatric intensive care unit in a university-affiliated hospital.

RESULTS

The patient presented with respiratory failure and central nervous system depression. Specific questioning of the parents revealed consumption of folk herbal remedy by the neonate. Mechanical ventilation was used for 24 hours until normal activity level resumed.

CONCLUSIONS

The possibility of intoxication in a neonate should not be overlooked. Folk herbal remedies, especially if taken in larger than recommended amounts, may be hazardous. Accessible herbal and folk medicine data bank will contribute to a better treatment of patients having side effects of these remedies.

Drug bioactivation, covalent binding to target proteins and toxicity relevance

A number of therapeutic drugs with different structures and mechanisms of action have been reported to undergo metabolic activation by Phase I or Phase II drug-metabolizing enzymes. The bioactivation gives rise to reactive metabolites/intermediates, which readily confer covalent binding to various target proteins by nucleophilic substitution and/or Schiff's base mechanism. These drugs include analgesics (e.g., acetaminophen), antibacterial agents (e.g., sulfonamides and macrolide antibiotics), anticancer drugs (e.g., irinotecan), antiepileptic drugs (e.g., carbamazepine), anti-HIV agents (e.g., ritonavir), antipsychotics (e.g., clozapine), cardiovascular drugs (e.g., procainamide and hydralazine), immunosupressants (e.g., cyclosporine A), inhalational anesthetics (e.g., halothane), nonsteroidal anti-inflammatory drugs (NSAIDSs) (e.g., diclofenac), and steroids and their receptor modulators (e.g., estrogens and tamoxifen). Some herbal and dietary constituents are also bioactivated to reactive metabolites capable of binding covalently and inactivating cytochrome P450s (CYPs). A number of important target proteins of drugs have been identified by mass spectrometric techniques and proteomic approaches. The covalent binding and formation of drug-protein adducts are generally considered to be related to drug toxicity, and selective protein covalent binding by drug metabolites may lead to selective organ toxicity. However, the mechanisms involved in the protein adduct-induced toxicity are largely undefined, although it has been suggested that drug-protein adducts may cause toxicity either through impairing physiological functions of the modified proteins or through immune-mediated mechanisms. In addition, mechanism-based inhibition of CYPs may result in toxic drug-drug interactions. The clinical consequences of drug bioactivation and covalent binding to proteins are unpredictable, depending on many factors that are associated with the administered drugs and patients. Further studies using proteomic and genomic approaches with high throughput capacity are needed to identify the protein targets of reactive drug metabolites, and to elucidate the structure-activity relationships of drug's covalent binding to proteins and their clinical outcomes.

Herbal bioactivation: the good, the bad and the ugly

It has been well established that the formation of reactive metabolites of drugs is associated with drug toxicity. Similarly, there are accumulating data suggesting the role of the formation of reactive metabolites/intermediates through bioactivation in herbal toxicity and carcinogenicity. It has been hypothesized that the resultant reactive metabolites following herbal bioactivation covalently bind to cellular proteins and DNA, leading to toxicity via multiple mechanisms such as direct cytotoxicity, oncogene activation, and hypersensitivity reactions. This is exemplified by aristolochic acids present in Aristolochia spp, undergoing reduction of the nitro group by hepatic cytochrome P450 (CYP1A1/2) or peroxidases in extrahepatic tissues to reactive cyclic nitrenium ion. The latter was capable of reacting with DNA and proteins, resulting in activation of H-ras oncogene, gene mutation and finally carcinogenesis. Other examples are pulegone present in essential oils from many mint species; and teucrin A, a diterpenoid found in germander (Teuchrium chamaedrys) used as an adjuvant to slimming diets. Extensive pulegone metabolism generated p-cresol that was a glutathione depletory, and the furan ring of the diterpenoids in germander was oxidized by CYP3A4 to reactive epoxide which reacts with proteins such as CYP3A and epoxide hydrolase. On the other hand, some herbal/dietary constituents were shown to form reactive intermediates capable of irreversibly inhibiting various CYPs. The resultant metabolites lead to CYP inactivation by chemical modification of the heme, the apoprotein, or both as a result of covalent binding of modified heme to the apoprotein. Some examples include bergamottin, a furanocoumarin of grapefruit juice; capsaicin from chili peppers; glabridin, an isoflavan from licorice root; isothiocyanates found in all cruciferous vegetables; oleuropein rich in olive oil; dially sulfone found in garlic; and resveratrol, a constituent of red wine. CYPs have been known to metabolize more than 95% therapeutic drugs and activate a number of procarcinogens as well. Therefore, mechanism-based inhibition of CYPs may provide an explanation for some reported herb-drug interactions and chemopreventive activity of herbs. Due to the wide use and easy availability of herbal medicines, there is increasing concern about herbal toxicity. The safety and quality of herbal medicine should be ensured through greater research, pharmacovigilance, greater regulatory control and better communication between patients and health professionals.