Antioxidant properties of -carboline alkaloids are related to their antimutagenic and antigenotoxic activities

Antidepressive, anxiolytic, and antiaddictive effects of ayahuasca, psilocybin and lysergic acid diethylamide (LSD): a systematic review of clinical trials published in the last 25 years

To date, pharmacological treatments for mood and anxiety disorders and for drug dependence show limited efficacy, leaving a large number of patients suffering severe and persistent symptoms. Preliminary studies in animals and humans suggest that ayahuasca, psilocybin and lysergic acid diethylamide (LSD) may have antidepressive, anxiolytic, and antiaddictive properties. Thus, we conducted a systematic review of clinical trials published from 1990 until 2015, assessing these therapeutic properties. Electronic searches were performed using the PubMed, LILACS, and SciELO databases. Only clinical trials published in peer-reviewed journals were included. Of these, 151 studies were identified, of which six met the established criteria. Reviewed studies suggest beneficial effects for treatment-resistant depression, anxiety and depression associated with life-threatening diseases, and tobacco and alcohol dependence. All drugs were well tolerated. In conclusion, ayahuasca, psilocybin and LSD may be useful pharmacological tools for the treatment of drug dependence, and anxiety and mood disorders, especially in treatment-resistant patients. These drugs may also be useful pharmacological tools to understand psychiatric disorders and to develop new therapeutic agents. However, all studies reviewed had small sample sizes, and half of them were open-label, proof-of-concept studies. Randomized, double-blind, placebo-controlled studies with more patients are needed to replicate these preliminary findings.

Phytochemical Constituents and Antioxidant and Antimicrobial Activity of Selected Plants Used Traditionally as a Source of Food

Many indigenous plants have also been used as a source of food and medicine in many African rural communities in the past. The study investigated the antimicrobial activity, phytochemical constituent, and antioxidant activity of selected traditional plants used traditionally as a source of food and medicine. The methanol and water extracts of different plant parts were analyzed for phytochemicals using standard phytochemical screening reagents while the broth microdilution assays were used to analyze antimicrobial activities. Alkaloids, phenols, flavonoids, saponins, tannins, and terpenes were found in one or more of the plant extracts, and all the plant extracts demonstrated scavenging activities. The back extracts of Sclerocarya birrea and the leaf extracts of Garcinia livingstonei exhibit the best antioxidant activities, while the water and methanol back extracts of S. birrea and G. livingstonei were the most active against all the tested foodborne bacteria.

Treatment with harmine ameliorates functional impairment and neuronal death following traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of mortality in young individuals, and results in motor and cognitive deficiency. Excitotoxicity is an important process during neuronal cell death, which is caused by excessive release of glutamate following TBI. Astrocytic glutamate transporters have a predominant role in maintaining extracellular glutamate concentrations below excitotoxic levels, and glutamate transporter 1 (GLT-1) may account for >90% of glutamate uptake in the brain. The β-carboline alkaloid harmine has been demonstrated to exert neuroprotective actions in vivo, and the beneficial effects were specifically due to elevation of GLT-1. However, whether harmine provides neuroprotection following TBI remains to be elucidated. The present study performed intraperitoneal harmine injections in rats (30 mg/kg per day for up to 5 days), in order to investigate whether harmine treatment attenuates brain edema and improves functional recovery in a rat model of TBI. The neuronal survival ratio and the protein expression of apoptosis-associated caspase 3 were also assessed in the hippocampus of the rat brain. Furthermore, the expression levels of GLT-1 and inflammatory cytokines were detected, in order to determine the underlying mechanisms. The results of the present study demonstrated that administration of harmine significantly attenuated cerebral edema, and improved learning and memory ability. In addition, harmine significantly increased the protein expression of GLT-1, and markedly attenuated the expression levels of interleukin-1β and tumor necrosis factor-α, thereby attenuating apoptotic neuronal death in the hippocampus. These results provided in vivo evidence that harmine may exert neuroprotective effects by synergistically reducing excitotoxicity and inflammation following TBI.

Synthesis of novel tetrahydrobenzazepine derivatives and their cytoprotective effect on human lymphocytes

Cytoprotective compounds such as amifostine play an important role in chemo- and radiotherapy due to their ability to reduce the side effects of these treatments. Our work was initiated with the intention to design, synthesise and test a new class of heterocyclic compounds that would have an antioxidative profile with the potential to be further developed as cytoprotective agents. The design was based on the privileged tetrahydrobenzazepine scaffold found in many natural products with a wide range of biological properties. This structure was further functionalised with moieties known to possess antioxidative features such as tertiary amine and styrene double bond. A series of eight tetrahydrobenzazepine derivatives of isoquinoline, 3,4-dihydro-β-carboline and pyridine were synthesised employing the Heck reaction as a key transformation. Some of the prepared compounds were tested for their in vitro effects on chromosome aberrations in peripheral human lymphocytes using the cytochalasin-B blocked micronucleus (MN) assay. Three tetrahydrobenzoazepine derivatives showed significant cytoprotective properties, comparable or even better to those of the radioprotective agent amifostine.

Pb-induced responses in Zygophyllum fabago plants are organ-dependent and modulated by salicylic acid

Zygophyllum fabago is a promising species for restoring heavy metal (HM) polluted soils, although the mechanisms involved in HM tolerance in this non-model plant remain largely unknown. This paper analyses the extent to which redox-active compounds and enzymatic antioxidants in roots, stems and leaves are responsible for Pb tolerance in a metallicolous ecotype of Z. fabago and the possible influence of salicylic acid (SA) pretreatment (24 h, 0.5 mM SA) in the response to Pb stress. SA pretreatment reduced both the accumulation of Pb in roots and even more so the concentration of Pb in aerial parts of the plants, although a similar drop in the content of chlorophylls and in the maximum quantum yield of photosystem II was observed in both Pb- and SA-Pb-treated plants. Pb increased the endogenous free SA levels in all organs and this response was enhanced in root tissues upon SA pretreatment. Generally, Pb induced a reduction in catalase, ascorbate peroxidase and glutathione reductase specific activities, whereas dehydroascorbate reductase was increased in all organs of control plants. SA pretreatment enhanced the Pb-induced H2O2 accumulation in roots by up-regulating Fe-superoxide dismutase isoenzymes. Under Pb stress, the GSH redox ratio remained highly reduced in all organs while the ascorbic acid redox ratio dropped in leaf tissues where a rise in lipid peroxidation products and electrolyte leakage was observed. Finally, an organ-dependent accumulation of proline and β-carboline alkaloids was found, suggesting these nitrogen-redox-active compounds could play a role in the adaptation strategies of this species to Pb stress.

Hydroxyl radical reactions and the radical scavenging activity of β-carboline alkaloids

β-Carbolines are bioactive pyridoindole alkaloids occurring in foods, plants and the human body. Their activity as hydroxyl radical (OH) scavengers is reported here by using three different methods: deoxyribose degradation, hydroxylation of benzoate and hydroxylation of 2'-deoxyguanosine to give 8-hydroxy-2'-deoxyguanosine (8-OHdG) as assessed by RP-HPLC (MS). Fenton reactions (Fe(2+)/Fe(3+) plus H2O2) were used for OH generation, and the radical increased in the presence of ascorbic acid or 6-hydroxydopamine as pro-oxidants. β-Carbolines were scavengers of OH in the three assays and in the presence of pro-oxidants. Tetrahydro-β-carboline-3-carboxylic acids were active against the hydroxylation of 2'-deoxyguanosine. β-Carbolines reacted with hydroxyl radicals (OH) affording hydroxy-β-carbolines, whereas tetrahydro-β-carbolines gave oxidative and degradation products. On the basis of IC50 and reaction rates (k), β-carbolines (norharman and harman), and tetrahydro-β-carbolines (tetrahydro-β-carboline, 1-methyltetrahydro-β-carboline and pinoline) were good OH radical scavengers and their activity was comparable to that of the indole, melatonin, which is an effective hydroxyl radical scavenger and antioxidant.

Sequence specific binding of beta carboline alkaloid harmalol with deoxyribonucleotides: binding heterogeneity, conformational, thermodynamic and cytotoxic aspects

BACKGROUND

Base dependent binding of the cytotoxic alkaloid harmalol to four synthetic polynucleotides, poly(dA).poly(dT), poly(dA-dT).poly(dA-dT), poly(dG).poly(dC) and poly(dG-dC).poly(dG-dC) was examined by various photophysical and calorimetric studies, and molecular docking.

METHODOLOGY/PRINCIPAL FINDINGS

Binding data obtained from absorbance according to neighbor exclusion model indicated that the binding constant decreased in the order poly(dG-dC).poly(dG-dC)>poly(dA-dT).poly(dA-dT)>poly(dA).poly(dT)>poly(dG).poly(dC). The same trend was shown by the competition dialysis, change in fluorescence steady state intensity, stabilization against thermal denaturation, increase in the specific viscosity and perturbations in circular dichroism spectra. Among the polynucleotides, poly(dA).poly(dT) and poly(dG).poly(dC) showed positive cooperativity where as poly(dG-dC).poly(dG-dC) and poly(dA-dT).poly(dA-dT) showed non cooperative binding. Isothermal calorimetric data on the other hand showed enthalpy driven exothermic binding with a hydrophobic contribution to the binding Gibbs energy with poly(dG-dC).poly(dG-dC), and poly(dA-dT).poly(dA-dT) where as harmalol with poly(dA).poly(dT) showed entropy driven endothermic binding and with poly(dG).poly(dC) it was reported to be entropy driven exothermic binding. The study also tested the in vitro chemotherapeutic potential of harmalol in HeLa, MDA-MB-231, A549, and HepG2 cell line by MTT assay.

CONCLUSIONS/SIGNIFICANCE

Studies unequivocally established that harmalol binds strongly with hetero GC polymer by mechanism of intercalation where the alkaloid resists complete overlap to the DNA base pairs inside the intercalation cavity and showed maximum cytotoxicity on HepG2 with IC50 value of 14 µM. The results contribute to the understanding of binding, specificity, energetic, cytotoxicity and docking of harmalol-DNA complexation that will guide synthetic efforts of medicinal chemists for developing better therapeutic agents.

Ayahuasca and cancer treatment

OBJECTIVES

Comprehensively review the evidence regarding the use of ayahuasca, an Amerindian medicine traditionally used to treat many different illnesses and diseases, to treat some types of cancer.

METHODS

An in-depth review of the literature was conducted using PubMed, books, institutional magazines, conferences and online texts in nonprofessional sources regarding the biomedical knowledge about ayahuasca in general with a specific focus in its possible relations to the treatment of cancer.

RESULTS

At least nine case reports regarding the use of ayahuasca in the treatment of prostate, brain, ovarian, uterine, stomach, breast, and colon cancers were found. Several of these were considered improvements, one case was considered worse, and one case was rated as difficult to evaluate. A theoretical model is presented which explains these effects at the cellular, molecular, and psychosocial levels. Particular attention is given to ayahuasca's pharmacological effects through the activity of N,N-dimethyltryptamine at intracellular sigma-1 receptors. The effects of other components of ayahuasca, such as harmine, tetrahydroharmine, and harmaline, are also considered.

CONCLUSION

The proposed model, based on the molecular and cellular biology of ayahuasca's known active components and the available clinical reports, suggests that these accounts may have consistent biological underpinnings. Further study of ayahuasca's possible antitumor effects is important because cancer patients continue to seek out this traditional medicine. Consequently, based on the social and anthropological observations of the use of this brew, suggestions are provided for further research into the safety and efficacy of ayahuasca as a possible medicinal aid in the treatment of cancer.

The β-carboline alkaloid harmine inhibits telomerase activity of MCF-7 cells by down-regulating hTERT mRNA expression accompanied by an accelerated senescent phenotype

The end replication problem, which occurs in normal somatic cells inducing replicative senescence, is solved in most cancer cells by activating telomerase. The activity of telomerase is highly associated with carcinogenesis which makes the enzyme an attractive biomarker in cancer diagnosis and treatment. The indole alkaloid harmine has multiple pharmacological properties including DNA intercalation which can lead to frame shift mutations. In this study, harmine was applied to human breast cancer MCF-7 cells. Its activity towards telomerase was analyzed by utilizing the telomeric repeat amplification protocol (TRAP). Our data indicate that harmine exhibits a pronounced cytotoxicity and induces an anti-proliferation state in MCF-7 cells which is accompanied by a significant inhibition of telomerase activity and an induction of an accelerated senescence phenotype by over-expressing elements of the p53/p21 pathway.

The β-carboline alkaloid harmine inhibits telomerase activity of MCF-7 cells by down-regulating hTERT mRNA expression accompanied by an accelerated senescent phenotype

The end replication problem, which occurs in normal somatic cells inducing replicative senescence, is solved in most cancer cells by activating telomerase. The activity of telomerase is highly associated with carcinogenesis which makes the enzyme an attractive biomarker in cancer diagnosis and treatment. The indole alkaloid harmine has multiple pharmacological properties including DNA intercalation which can lead to frame shift mutations. In this study, harmine was applied to human breast cancer MCF-7 cells. Its activity towards telomerase was analyzed by utilizing the telomeric repeat amplification protocol (TRAP). Our data indicate that harmine exhibits a pronounced cytotoxicity and induces an anti-proliferation state in MCF-7 cells which is accompanied by a significant inhibition of telomerase activity and an induction of an accelerated senescence phenotype by over-expressing elements of the p53/p21 pathway.

Identification of new natural DNA G-quadruplex binders selected by a structure-based virtual screening approach

The G-quadruplex DNA structures are mainly present at the terminal portion of telomeres and can be stabilized by ligands able to recognize them in a specific manner. The recognition process is usually related to the inhibition of the enzyme telomerase indirectly involved and over-expressed in a high percentage of human tumors. There are several ligands, characterized by different chemical structures, already reported in the literature for their ability to bind and stabilize the G-quadruplex structures. Using the structural and biological information available on these structures; we performed a high throughput in silico screening of commercially natural compounds databases by means of a structure-based approach followed by docking experiments against the human telomeric sequence d[AG₃(T₂AG₃)₃]. We identified 12 best hits characterized by different chemical scaffolds and conformational and physicochemical properties. All of them were associated to an improved theoretical binding affinity with respect to that of known selective G-binders. Among these hits there is a chalcone derivative; structurally very similar to the polyphenol butein; known to remarkably inhibit the telomerase activity.

Evaluation of Acute 13-Week Subchronic Toxicity and Genotoxicity of the Powdered Root of Tongkat Ali (Eurycoma longifolia Jack)

Tongkat Ali (Eurycoma longifolia) is an indigenous traditional herb in Southern Asia. Its powdered root has been processed to produce health supplements, but no detailed toxicology report is available. In this study, neither mutagenicity nor clastogenicity was noted, and acute oral LD50 was more than 6 g/kg b.w. After 4-week subacute and 13-week subchronic exposure paradigms (0, 0.6, 1.2, and 2 g/kg b.w./day), adverse effects attributable to test compound were not observed with respect to body weight, hematology, serum biochemistry, urinalysis, macropathology, or histopathology. However, the treatment significantly reduced prothrombin time, partial thromboplastin time, blood urea nitrogen, creatinine, aspartate aminotransferase, creatine phosphate kinase, lactate dehydrogenase, and cholesterol levels, especially in males (P < 0.05). These changes were judged as pharmacological effects, and they are beneficial to health. The calculated acceptable daily intake (ADI) was up to 1.2 g/adult/day. This information will be useful for product development and safety management.

Medicinal Plant Active Compounds Produced by UV-B Exposure

Ultraviolet (UV) radiation is a part of the sunlight reaching Earth surface. The UV spectrum of solar radiation is by convention divided into three parts: UV-A: 310–400 nm, UV-B: 280–310 nm and UV-C: less than 280 nm. UV-B is the most energetic component reaching Earth surface because the stratospheric ozone layer effectively absorbs completely wavelengths below 290 nm. UV-B is an increasing threat due to increasing UV-B levels on Earth surface as a consequence of depletion of stratospheric O₃. In general, the effects of atmospheric UV-B radiation are negative for biological life. Enhanced levels of UV-B radiation can indeed negatively change plant physiological processes, growth and productivity. However, while studying UV-B effects on medicinal plants, some interesting phenomena have been discovered. For example, basil plants respond positively to UV-B radiation by increasing oil yield (Chang et al. J Horticult For 1:27–31, 2009). In other studies medicinal plants show beneficial aspects in term of increase in volatile oil yield and secondary metabolite production (Kumari et al. Ecotoxicol Environ Safety 72:2013–2019, 2009c, 2010). Medicinal herbs have great market value in India and worldwide. The medicinal value of plants depends upon phenolics, antioxidants and volatile yield. Therefore further UV-B experiments increasing the levels of these compounds are needed.

Here we review the effect of UV-B exposure on metabolites, volatiles, and antioxidants potential in medicinal plants. This chapter reports: (1) aspects of the global market for medicinal and aromatic plants in India in order to assist the medicinal plant industry to make informed decisions. (2) The biodiversity loss due to wild harvesting of plants, and as an alternative the cultivation strategy of medicinal plants. (3) Main medicinal plant species having rich antioxidant potential. (4) Main secondary metabolites of plant origin such as phenylpropanoids, terpenes, alkaloids, and volatile oil, and other important metabolites containing high antioxidant level used in human diet and health. (5) UV-B factors that enhance the quality of medicinal plant by increasing the content of secondary bioactive products. (6) Secondary metabolic pathways involving regulation of key enzymes, chalcone synthase, and phenylalanine ammonia lyase. Understanding of UV-B responses on secondary plant metabolites expand new opportunities for plant enriched in medicinal active compounds.

Genotoxic and mutagenic properties of Bauhinia platypetala extract, a traditional Brazilian medicinal plant

ETHNOPHARMACOLOGICAL RELEVANCE

Bauhinia platypetala Burch. is a traditionally used Brazilian medicinal plant, although no evidence in the literature substantiates the safety of its use.

AIM OF THE STUDY

The aim of this study was to investigate the safety of the ethanolic extract and the ethereal fraction of B. platypetala leaves.

MATERIALS AND METHODS

The identification of chemical compounds from the B. platypetala ethanolic extract and its ethereal fraction was performed by GC/MS and ESI-MS/MS. The plant's toxicological, cytotoxic, mutagenic and genotoxic properties were determined in Saccharomyces cerevisiae strains and V79 cell culture by survival assays and comet assay.

RESULTS

The major compound identified in the B. platypetala ethanolic extract is palmitic acid, kaempferitirin and quercitrin, while the B. platypetala ethereal fraction was found to be rich in phytol, gamma-sitosterol and vitamin E. Moreover, the results indicated that the B. platypetala ethanolic extract has an anti-oxidative effect against H(2)O(2) in yeast. In addition, the B. platypetala ethanolic extract did not induce mutagenic effects on the S. cerevisiae N123 strain, but the ethereal fraction of B. platypetala at higher concentrations (250-500 μg/mL) induced cytotoxicity and mutagenicity. A slight cytotoxic effect was observed in mammalian V79 cells; however, both the B. platypetala ethanolic extract and its ethereal fraction were able to induce DNA strand breaks in V79 cells, as detected by the alkaline comet assay.

CONCLUSION

The B. platypetala ethanolic extract has antioxidant action and showed absence of mutagenic effects in yeast S. cerevisiae. On the other hand B. platypetala ethereal fraction is mutagenic and does not show antioxidant activity in yeast. In mammalian cells B. platypetala ethanolic extract and it's ethereal fraction induce cyotoxic and genotoxic action.

Treatment with aqueous extract from Croton cajucara Benth reduces hepatic oxidative stress in streptozotocin-diabetic rats

Croton cajucara Benth is a plant found in Amazonia, Brazil and the bark and leaf infusion of this plant have been popularly used to treat diabetes and hepatic disorders. The present study was designed to evaluate the oxidative stress as well as the therapeutic effect of Croton cajucara Benth (1.5 mL of the C. cajucara extract i.g.) in rats with streptozotocin-induced diabetes. Croton cajucara Benth was tested as an aqueous extract for its phytochemical composition, and its antioxidant activity in vitro was also evaluated. Lipid peroxidation and superoxide dismutase, catalase, and glutathione reductase activities were measured in the hepatic tissue, as well as the presence activation of p65 (NF-κB), through western blot. Phytochemical screening of Croton cajucara Benth detected the presence of flavonoids, coumarins and alkaloids. The extract exhibited a significant antioxidant activity in the DPPH-scavenging and the hypoxanthine/xanthine oxidase assays. Liver lipid peroxidation increased in diabetic animals followed by a reduction in the Croton-cajucara-Benth-treated group. There was activation of p65 nuclear expression in the diabetic animals, which was attenuated in the animals receiving the Croton cajucara Benth aqueous extract. The liver tissue in diabetic rats showed oxidative alterations related to the streptozotocin treatment. In conclusion the Croton cajucara Benth aqueus extract treatment effectively reduced the oxidative stress and contributed to tissue recovery.

The potential of synthetic thiourea compound to reduce the cytotoxic and genotoxic effects of paraquat in Hordeum vulgare and cultured human lymphocytes

This work evaluated the ability of one synthetic compound 1-(4-fluorophenylthiocarbamoyl)-4-methyl-piperazine (FTMP), thiourea derivative to reduce cytotoxic and genotoxic effects of free radical inducer paraquat (PQ) in two different test systems Hordeum vulgare and human lymphocytes in vitro. The mitotic index was used as a marker for cytotoxicity. To indicate genotoxicity, chromosome aberrations test and micronucleus induction test were used. FTMP manifested a weak genotoxic effect in both test systems. Clear evidence was obtained that conditioning treatment with FTMP (10(-6) , 5 × 10(-6) , and 10(-5) mol/l) could decrease chromosome aberrations and micronuclei induced by PQ in both test systems. "Aberration hot spots" in heterochromatin containing segments were reduced. The present data show that the thiourea synthetic compound FTMP provides genome protection against the harmful action of oxidative stress inductor PQ. Human lymphocytes were found to be more sensitive to the cytotoxic and clastogenic effects of FTMP conditioning treatment than Hordeum vulgare. Revealing the protective action of newly synthesized compounds could contribute to the improvement of our present knowledge of the mechanisms of mutagenesis and antimutagenesis.

Harmaline and harmalol inhibit the carcinogen-activating enzyme CYP1A1 via transcriptional and posttranslational mechanisms

Dioxins are known to cause several human cancers through activation of the aryl hydrocarbon receptor (AhR). Harmaline and harmalol are dihydro-β-carboline compounds present in several medicinal plants such as Peganum harmala. We have previously demonstrated the ability of P. harmala extract to inhibit TCDD-mediated induction of Cyp1a1 in murine hepatoma Hepa 1c1c7 cells. Therefore, the aim of this study is to examine the effect of harmaline and its main metabolite, harmalol, on dioxin-mediated induction of CYP1A1 in human hepatoma HepG2 cells. Our results showed that harmaline and harmalol at concentrations of (0.5-12.5μM) significantly inhibited the dioxin-induced CYP1A1 at mRNA, protein and activity levels in a concentration-dependent manner. The role of AhR was determined by the inhibition of the TCDD-mediated induction of AhR-dependent luciferase activity and the AhR/ARNT/XRE formation by both harmaline and harmalol. In addition, harmaline significantly displaced [(3)H]TCDD in the competitive ligand binding assay. At posttranslational level, both harmaline and harmalol decreased the protein stability of CYP1A1, suggesting that posttranslational modifications are involved. Moreover, the posttranslational modifications of harmaline and harmalol involve ubiquitin-proteasomal pathway and direct inhibitory effects of both compounds on CYP1A1 enzyme. These data suggest that harmaline and harmalol are promising agents for preventing dioxin-mediated effects.

Transcriptional and posttranslational inhibition of dioxin-mediated induction of CYP1A1 by harmine and harmol

Dioxins are widespread environmental contaminants that induce the carcinogen-activating enzyme, cytochrome P450 1A1 (CYP1A1) through an aryl hydrocarbon receptor (AhR)-dependent mechanism. We previously demonstrated that harmine inhibits the dioxin-mediated induction of Cyp1a1 activity in murine hepatoma cells. Therefore, the aim of this study is to determine the effect of harmine and its main metabolite, harmol, on the dioxin-mediated induction of CYP1A1 in human HepG2 and murine Hepa 1c1c7 hepatoma cells. Our results showed that harmine and harmol significantly inhibited the dioxin-mediated induction of CYP1A1 at mRNA, protein, and activity levels in a concentration-dependent manner in human and murine hepatoma cells. Moreover, harmine and harmol inhibited the AhR-dependent luciferase activity and the activation and transformation of AhR using the electrophoretic mobility shift assay. In addition, harmine and harmol displaced [(3)H]TCDD in the competitive ligand binding assay. At posttranslational level, both harmine and harmol decreased the protein stability of CYP1A1, suggesting that posttranslational mechanism is involved. Furthermore, we demonstrated that the underlying mechanisms of the posttranslational modifications of both compounds involve ubiquitin-proteasomal pathway and direct inhibitory effects of CYP1A1 enzyme. We concluded that harmine and its metabolite, harmol, are new inhibitors of dioxin-mediated effects.

Methodology for determining major constituents of ayahuasca and their metabolites in blood

There is an increasing interest in potential medical applications of ayahuasca, a South American psychotropic plant tea with a long cultural history of indigenous medical and religious use. Clinical research into ayahuasca will require specific, sensitive and comprehensive methods for the characterization and quantitation of these compounds and their metabolites in blood. A combination of two analytical techniques (high-performance liquid chromatography with ultraviolet and/or fluorescence detection and gas chromatography with nitrogen-phosphorus detection) has been used for the analysis of some of the constituents of ayahuasca in blood following its oral consumption. We report here a single methodology for the direct analysis of 14 of the major alkaloid components of ayahuasca, including several known and potential metabolites of N,N-dimethyltryptamine and the harmala alkaloids in blood. The method uses 96-well plate/protein precipitation/filtration for plasma samples, and analysis by HPLC-ion trap-ion trap-mass spectrometry using heated electrospray ionization to reduce matrix effects. The method expands the list of compounds capable of being monitored in blood following ayahuasca administration while providing a simplified approach to their analysis. The method has adequate sensitivity, specificity and reproducibility to make it useful for clinical research with ayahuasca.

Screening of medicinal plants from Iranian traditional medicine for acetylcholinesterase inhibition

To find new herbal compounds with an acetylcholinesterase (AChE) inhibitory effect, this study focused on herbal drugs and resins which have been used in Iranian traditional medicine for the treatment of cognitive disorders. Forty drugs were selected from authoritative written documents of Iranian traditional medicine. Each drug was extracted by accelerated solvent extraction using dichloromethane followed by methanol. The 80 extracts were screened for AChE inhibitory activity by a TLC bioautography method. The inhibiting effect of the 32 most active extracts was measured by a microplate colorimetric assay. Due to the best activity, the seeds of Peganum harmala L. were investigated in detail. From the TLC bioautography assay the alkaloids harmaline and harmine were identified as active compounds. This result was confirmed by means of HPLC-DAD. The IC(50) values were 41.2 μg/mL for the methanol extract, 95.5 μg/mL for the dichloromethane extract, 8.4 μg/mL for harmaline and 10.9 μg/mL for harmine. The concentrations of active compounds in the extracts were determined by a fast and precise HPLC method. As the amounts of harmaline and harmine in the extracts were correlated with the IC(50) values of the extracts, it can be concluded that these two alkaloids are responsible for the AChE inhibitory activity of P. harmala.

Methodology for and the determination of the major constituents and metabolites of the Amazonian botanical medicine ayahuasca in human urine

Ayahuasca, also known as caapi or yage among various South American groups, holds a highly esteemed and millennia-old position in these cultures' medical and religious pharmacopeia. There is now an increasing interest in the potential for modern medical applications of ayahuasca, as well as concerns regarding its increasing potential for abuse. Toxicological and clinical research to address these issues will require information regarding its metabolism and clearance. Thus, a rapid, sensitive and specific method for characterization and quantitation of the major constituents and of the metabolites of ayahuasca in urine is needed. The present research provides a protocol for conducting such analyses. The characteristics of the method, conducted by sample dilution and using HPLC-electrospray ionization (ESI)-selected reaction monitoring (SRM)-tandem mass spectrometry, are presented. The application of the analytical protocol to urine samples collected from three individuals that were administered ayahuasca has also been demonstrated. The data show that the major metabolite of the hallucinogenic component of ayahuasca, N,N-dimethyltryptamine (DMT), is the corresponding N-oxide, the first time this metabolite has been described in in vivo studies in humans. Further, very little DMT was detected in urine, despite the inhibition of monoamine oxidase afforded by the presence of the harmala alkaloids in ayahuasca. The major harmala alkaloid excreted was tetrahydroharmine. Other excretion products and metabolites were also identified and quantified. The method described would be suitable for use in further toxicological and clinical research on ayahuasca.

Evaluation of antigenotoxic effects of juices of plants Chelidonium majus L., Plantago major L. и Tussilago farfara L

The antigenotoxic effects of juices of three medicinal plants, Chelidonium majus L., Plantago major L. and Tussilago farfara L. has been studied in two bacterial tests — SOS chromotest and Rec assay. Antigenotoxic effect was determined against known genotoxic substances — nalidixic acid in SOS chromotest and furacilin in Rec assay. Preparations obtained from the leaves of Ch. majus L. exhibited significant antigenotoxic effect in both the SOS chromotest and the Rec assay. It was shown that dilution of the herb juice of T. farfara L resulted in high bioantimutagenic activity in SOS chromotest. P. major L. preparations did not display statistically significant antigenotoxic activity in the both tests used. Possible mechanisms of antigenotoxic effects of Ch. majus L. and T. farfara L. plants obtained are discussed.

Acute harmine administration induces antidepressive-like effects and increases BDNF levels in the rat hippocampus

Harmine is a beta-carboline alkaloid that inhibits monoamine reuptake systems. Findings point to an antidepressant effect of the compounds that increases the levels of monoamines after monoamine oxidase inhibition. The present study aims to compare the behavioral effects and the BDNF hippocampus levels of acute administration of harmine and imipramine in rats. To this aim, rats were acutely treated with harmine (5, 10 and 15 mg/kg) and imipramine (10, 20 and 30 mg/kg) and animal behavior was assessed in the forced swimming and open-field tests. Afterwards, hippocampal BDNF protein levels were assessed in imipramine- and harmine-treated rats by ELISA-sandwich assay. We observed that harmine at doses of 10 and 15 mg/kg, and imipramine at 20 and 30 mg/kg reduced immobility time, and increased both climbing and swimming time of rats compared to saline group, without affecting locomotor activity. Acute administration of harmine at the higher dose, but not imipramine, increased BDNF protein levels in the rat hippocampus. Finally, these findings further support the hypothesis that harmine could be a new pharmacological target for the treatment of mood disorders.

Direct analysis of psychoactive tryptamine and harmala alkaloids in the Amazonian botanical medicine ayahuasca by liquid chromatography-electrospray ionization-tandem mass spectrometry

A direct injection/liquid chromatography-electrospray ionization-tandem mass spectrometry procedure has been developed for the simultaneous quantitation of 11 compounds potentially found in the increasingly popular Amazonian botanical medicine and religious sacrament ayahuasca. The method utilizes a deuterated internal standard for quantitation and affords rapid detection of the alkaloids by a simple dilution assay, requiring no extraction procedures. Further, the method demonstrates a high degree of specificity for the compounds in question, as well as low limits of detection and quantitation despite using samples for analysis that had been diluted up to 200:1. This approach also appears to eliminate potential matrix effects. Method bias for each compound, examined over a range of concentrations, was also determined as was inter- and intra-assay variation. Its application to the analysis of three different ayahuasca preparations is also described. This method should prove useful in the study of ayahuasca in clinical and ethnobotanical research as well as in forensic examinations of ayahuasca preparations.

Effects of beta-carboline harmine on behavioral and physiological parameters observed in the chronic mild stress model: further evidence of antidepressant properties

The chronic mild stress (CMS) model has been used as an animal model of depression which induces anhedonic behavior in rodents. The present study was aimed to evaluate the behavioral and physiological effects of administration of beta-carboline harmine in rats exposed to CMS procedure. To this aim, after 40 days of exposure to CMS procedure, rats were treated with harmine (15 mg/kg/day) for 7 days. In this study, sweet food consumption, adrenal gland weight, adrenocorticotrophin hormone (ACTH) levels, and hippocampal brain-derived-neurotrophic factor (BDNF) protein levels were assessed. Our findings demonstrated that chronic stressful situations induced anhedonia, hypertrophy of adrenal gland weight, increase ACTH circulating levels in rats and increase BDNF protein levels. Interestingly, treatment with harmine reversed anhedonia, the increase of adrenal gland weight, normalized ACTH circulating levels and BDNF protein levels. Finally, these findings further support the hypothesis that harmine could be a new pharmacological tool for the treatment of depression.

Effects of CYP2D6 status on harmaline metabolism, pharmacokinetics and pharmacodynamics, and a pharmacogenetics-based pharmacokinetic model

Harmaline is a beta-carboline alkaloid showing neuroprotective and neurotoxic properties. Our recent studies have revealed an important role for cytochrome P450 2D6 (CYP2D6) in harmaline O-demethylation. This study, therefore, aimed to delineate the effects of CYP2D6 phenotype/genotype on harmaline metabolism, pharmacokinetics (PK) and pharmacodynamics (PD), and to develop a pharmacogenetics mechanism-based compartmental PK model. In vitro kinetic studies on metabolite formation in human CYP2D6 extensive metabolizer (EM) and poor metabolizer (PM) hepatocytes indicated that harmaline O-demethylase activity (V(max)/K(m)) was about 9-fold higher in EM hepatocytes. Substrate depletion showed mono-exponential decay trait, and estimated in vitro harmaline clearance (CL(int), microL/min/10(6)cells) was significantly lower in PM hepatocytes (28.5) than EM hepatocytes (71.1). In vivo studies in CYP2D6-humanized and wild-type mouse models showed that wild-type mice were subjected to higher and longer exposure to harmaline (5 and 15mg/kg; i.v. and i.p.), and more severe hypothermic responses. The PK/PD data were nicely described by our pharmacogenetics-based PK model involving the clearance of drug by CYP2D6 (CL(CYP2D6)) and other mechanisms (CL(other)), and an indirect response PD model, respectively. Wild-type mice were also more sensitive to harmaline in marble-burying tests, as manifested by significantly lower ED(50) and steeper Hill slope. These findings suggest that distinct CYP2D6 status may cause considerable variations in harmaline metabolism, PK and PD. In addition, the pharmacogenetics-based PK model may be extended to define PK difference caused by other polymorphic drug-metabolizing enzyme in different populations.

Occupational exposure of farm workers to pesticides: biochemical parameters and evaluation of genotoxicity

To assess the effects of exposure to complex mixtures of pesticides in farm workers from two communities from Rio Grande do Sul, Brazil, we evaluated the activities of butyrylcholinesterase (BChE) and delta-aminolevulinic acid dehydratase (ALA-D) enzymes, hematological, lipid parameters, and genotoxicity using two tests to detect DNA damage, the Comet assay in peripheral blood leukocytes and the micronucleus (MN) test in oral mucosa cells. The use of personal protective equipment (PPE), age and smoke habits were considered in the analysis. There was a significant decrease in the BChE and ALA-D activities in farm workers (n=37) relative to the control group (n=20) (P< or =0.05 and P< or =0.001, respectively). The Comet assay in peripheral blood leukocytes showed that the Damage index and Damage frequency observed in the exposed group were significantly higher in relation to the controls (P< or =0.001, and P< or =0.05, respectively). No differences were detected regarding the hematological parameters, lipids profile, and MN frequencies. In addition, no significant differences were observed between younger (< or =38 years) and older subjects (>38 years), or between smokers and non-smokers within the groups, either by Comet assay or MN test. However, the use of PPE seems to be important in the prevention of contamination, as suggested by BChE levels and Comet assay results.