Constituents of Erythroxylon coca. II. Gas-chromatographic analysis of cocaine and other alkaloids in coca leaves

Impurities, adulterants and cutting agents in cocaine as potential candidates for retrospective mining of GC-MS data

Cocaine is one of the most widely used illicit drugs worldwide. Cocaine powders seized by the Police may contain numerous other substances besides the drug itself. These can be impurities originating from the coca plant or the production process, or be purposely added to the drug formulation as adulterants and cutting agents. In forensic laboratories, identification of cocaine is routinely done through GC-MS analysis, but other components are often ignored even if the method allows for their detection. Yet, they can provide valuable insight into the history of a seizure and its potential connection to other samples. To explore this idea, an extensive review of common impurities and adulterants encountered in cocaine is presented. Based on their incidence, concentration in the end product and compatibility with GC-MS methods, their overall usefulness as candidates for the statistical investigation of existing forensic data is evaluated. The impurities cis- and trans-cinnamoylcocaine, tropacocaine, norcocaine and N-benzoylnormethylecgonine as well as the adulterants lidocaine, procaine, tetracaine, benzocaine, caffeine, acetylsalicylic acid, phenacetin, ibuprofen, levamisole, hydroxyzine and diltiazem are promising candidates to provide additional forensic intelligence. Future research on optimized routine GC-MS methods, signal reproducibility, comparison, statistics and databases is suggested to facilitate this concept. Ultimately, such an approach may significantly advance the amount of information that is extracted from routine casework data, elucidate developments in the cocaine markets in the past and facilitate Police work in the future. Preliminary assessment of existing data from the forensic laboratory of the Amsterdam Police has been included to show that the detection of the identified target impurities is feasible, and that small adjustments to the analysis method could significantly increase the detectability of these analytes in prospective drug screenings. Forensic intelligence based on retrospective data mining of cocaine containing casework samples may thus be realized with minimal additional laboratory efforts by using already available instrumentation, samples and data.

Can coca leaves contribute to improving the nutritional status of the Andean population?

BACKGROUND

Coca leaves (Erythroxylum coca) have been promoted as a food that could address the dietary deficiencies of the Andean population, but this is based on nutrient analyses of a small sample of leaves.

OBJECTIVE

We assessed the nutritional potential of eight samples of coca leaves grown in different regions of Peru.

METHODS

We used AOAC techniques to measure nutrients, nutrient inhibitors (phytate, polyphenols, oxalic acid, and fiber), and alkaloid concentrations, all expressed per 100 g dry weight (DW) of the ground leaves. Minerals were measured by inductively coupled lasma- mass spectrometry in n twondependent laboratories.

RESULTS

The leaves contained protein, , 20.28 g/1 0DW with lysine as the limiting amino acid; n-cbetarotene, 3.51 mg/100gDW ; vitamin E, 16.72 mg/100gDW ; trace amounts of vitamin D; calcium, 990.18 and 1033.17 mg/100 gDW at two different laboratories; iron, 29.16 and 29.16 mg/100 gDW; zinc, 2.71 and 2.63 mg/100 gDW; and magnesium, 225.19 and 196.69 mg/l001gDW Cocaine was the principal alkaloid, with a concentration of 0.56 g/100 gDW; other alkaloids were also identified. The results were compared with those for other edible leaves. The nutrient contributions of coca powder (5 g) and bread made with coca were compared with those of normal portions of alternative foods.

CONCLUSIONS

Two spoonfuls of coca leaf flour would satisfy less than 10% of dietary intakes for schoolchildren and adults for critical commonly deficient nutrients in the diet. Coca leaves do not provide nutritional benefits when eaten in the recommended quantities, and the presence of absorbable cocaine and other alkaloids may be potentially harmful; hence coca leaves cannot be recommended as a food.

Brazilian plants with possible action on the central nervous system: a study of historical sources from the 16th to 19th century

Brazil is a country rich in biodiversity, endemism, and cultural diversity, inhabited by different types of population. European expeditions and the migratory processes that began in the 16th century greatly contributed both to cultural diversity and to Brazilian popular therapeutics, and produced the first records on medicinal plants in Brazil. This study comprises a bibliographical survey of historic books found in Sao Paulo libraries (16th through 19th centuries) on medicinal plants exerting effects on the central nervous system (CNS). Thirty-four plants native to Brazil were selected from the reading of the books. Of these 34 plants, 13 were also recorded in ethnopharmacological studies among modern Brazilian communities and 16 have been studied phytochemically. Only eight have been the object of pharmacological studies, six of these, recently, with a request for a patent. Results showed that most of the species recorded in this study have been reported as medicinal for centuries, but have never been the object of pharmacological investigation down to the present time. Such results provide ideas for a selection of these species as potentially bioactive to be included in future pharmacological studies.

Identification of Erythroxylum taxa by AFLP DNA analysis

Erythroxylum coca, indigenous to the Andean region of South America, is grown historically as a source of homeopathic medicine. However, in the last century, cultivation of E. coca and several closely-related species for the production of illicit cocaine has become a major global problem. Two subspecies, E. coca var. coca and E. coca var. ipadu, are almost indistinguishable phenotypically; a related cocaine-bearing species also has two subspecies (E. novogranatense var. novogranatense and E. novogranatense var. truxillense) that are phenotypically similar, but morphologically distinguishable. The purpose of this research was to discover unique AFLP DNA patterns ("genetic fingerprinting") that characterize the four taxa and then, if successful, to evaluate this approach for positive identification of the various species of coca. Of seven different AFLP primer pairs tested, a combination of five proved optimal in differentiating the four taxa as well as a non-cocaine-bearing species, E. aerolatum. This method of DNA fragment separation was selective, and faster, for coca identification, compared with analyses based on flavonoid chemotaxonomy. Using the 5-primer AFLP approach, 132 known and unknown coca leaf accessions were evaluated. Of these, 38 were collected in 1997-2001 from illicit coca fields in Colombia, and all were genetically differentiated from coca originating in Peru and Bolivia. Based on the DNA profiling, we believe that the Colombian coca now represents a hybridization of E. coca var. ipadu. Geographical profiling within Colombia also seems feasible as new coca production areas are developed or new types of coca are introduced within traditional growing areas.

Comparative analysis of heroin and cocaine seizures

In this brief review the analytical techniques mainly used for comparative analysis of both cocaine and heroin seizures are reported. The characterization of illicit samples is carried out by means of a variety of techniques including thin-layer chromatography, high-performance liquid chromatography, gas chromatography and capillary electrophoresis. By means of these technique it is possible to resolve some component in illicit drugs and their application for comparative analyses is described in this review. Owing to the complexity and the variability of the mixture related to the origin and manufacturing impurities a unique analytical approach based on the application of a single technique it is not sufficient to achieve the requested global characterization of the sample for comparative purposes. Generally a complete characterization is obtained focusing on the identification of minor and major components, origin and manufacturing impurities other than trace compounds such as solvent residues. Nevertheless the application of a single robust methods able to resolve any possible significant marker compounds, is still not described and there is a need for a standardized general procedure suitable for a complete cross-examination of analytical data related to comparative analyses that can be carried out at an international level.

A study of the chemical composition of Erythroxylum coca var. coca leaves collected in two ecological regions of Bolivia

Coca-Erythroxylum coca Lamarck var. coca-remains one of the most common plants of the folk medicine of Bolivia used as a general stimulant. Aymara and Quechua natives prefer to chew the sweeter coca leaves from the Yungas (tropical mountain forests of the eastern slopes of the Andes) rather than those from the Chapare lowlands. The contents in cocaine and minor constituents of leaf samples cultivated in these regions does not rationalize this choice.

Identification and quantitation of alkaloids in coca tea

The consumption of coca tea is a common occurrence in many South American countries. The tea is often packaged in individual servings as tea bags which contain approximately 1 g of plant material. The consumption of coca tea leads to ingestion of cocaine and other alkaloids; however, there is little information available regarding the pharmacological or toxicological effects that result from consumption of coca tea. We performed a series of studies with coca tea bags from two South American countries, Peru and Bolivia. The alkaloidal content of the 'coca leaf' in coca tea bags was determined by two different extraction methods: Soxhlet extraction with methanol (exhaustive extraction), and mechanical agitation with methanol. Extracts were purified by solid-phase extraction (SPE) followed by analysis by gas chromatography/mass spectrometry (GC/MS). Coca tea prepared from Peruvian and Bolivian coca tea bags was also analyzed by SPE-GC/MS assay. In addition, urine specimens were analyzed from an individual who consumed one cup of Peruvian coca tea and one cup of Bolivian coca tea on separate occasions. Urine samples were analyzed by immunoassay (TDx) and SPE-GC/MS. Analysis of coca tea bags and coca tea indicated that cocaine, benzoylecgonine, ecgonine methyl ester and trans-cinnamoylcocaine were present in varying quantities. With exhaustive extraction, an average of 5.11 mg, and 4.86 mg of cocaine per tea bag were found in coca leaf from Peru and Bolivia, respectively. The average amounts of benzoylecgonine, ecgonine methyl ester in Peruvian coca leaf were 0.11 and 1.15 mg, and in Bolivian coca leaf were 0.12 and 2.93 mg per tea bag, respectively. trans-cinnamoylcocaine was found in trace amounts in Peruvian tea bags and 0.16 mg/tea bag of Bolivian tea. When tea was prepared, an average of 4.14 mg of cocaine was present in a cup of Peruvian coca tea and 4.29 mg of cocaine was present in Bolivian tea. Following the consumption of a cup of Peruvian tea by one individual, a peak urine benzoylecgonine concentration of 3940 ng/ml occurred 10 h after ingestion. Consumption of Bolivian coca tea resulted in a peak benzoylecgonine concentration of 4979 ng/ml at 3.5 h. The cumulative urinary excretion of benzoylecgonine after approximately 48 h, determined by GC/MS, was 3.11 mg and 2.69 mg after consumption of Peruvian and Bolivian coca tea, respectively. This study demonstrated that coca tea bags and coca tea contain a significant amount of cocaine and cocaine-related alkaloids and the consumption of a single cup of Peruvian or Bolivian coca tea produces positive drug test results for cocaine metabolites.

In-depth chromatographic analyses of illicit cocaine and its precursor, coca leaves

Chromatographic methodology used for the in-depth alkaloid analyses of coca leaves and for the characterization of alkaloidal impurities and manufacturing by-products in illicit refined cocaine samples is reviewed. This includes liquid-liquid partition and liquid-solid adsorption column chromatography, packed- and capillary-column gas chromatography with flame-ionization, electron-capture, nitrogen-phosphorous and mass spectrometric detection, and high-performance liquid chromatography with ultraviolet detection. The rationale supporting the presence and determination of processing impurities/by-products in cocaine samples is discussed, and chromatographic methodology used for the development of drug impurity signature profiles is presented.

Determination and in-depth chromatographic analyses of alkaloids in South American and greenhouse-cultivated coca leaves

Methodology is described for the detection and/or determination of cocaine and minor alkaloids in South American coca as well as in greenhouse- and tropical-cultivated field coca of known taxonomy. Coca leaf from Bolivia, Peru, Ecuador and Colombia were subjected to the determination of cocaine, cis- and trans-cinnamoylcocaine, tropacocaine, hygrine, cuscohygrine and the isomeric truxillines. The greenhouse samples were cocaine-bearing leaves of the genus Erythroxylum and included E. coca var. coca, E. novogranatense var. novogranatense and E. novogranatense var. truxillense, and the alkaloids determined were cocaine, ecgonine methyl ester, cuscohygrine, tropacocaine and the cinnamoylcocaines. The tropical-cultivated coca were E. novogranatense var. novogranatense and E. coca var. coca. Cocaine and minor alkaloids were isolated from basified powdered leaf samples using a toluene extractant, followed by acid-Celite column chromatography. The isolated alkaloids were determined by capillary gas chromatography with flame ionization or electron-capture detection. Methodology is also presented for the isolation and mass spectral analysis of numerous trace-level coca alkaloids of unknown structure.

A multidisciplinary overview of intoxicating snuff rituals in the western hemisphere

Part one of the paper discusses ethnobotanical, chemical and general pharmacological aspects of intoxicating snuff rituals in the western hemisphere. Four categories of ritual snuff ingredients arise from this multidisciplinary approach: It is well established that the plant contains one or more psychoactive principles and the Indian use of the plant as a ritual snuff ingredient is confirmed or quite probable: Anadenanthera, Erythroxylum, Nicotiana, Virola; It is well established that the plant contains one or more psychoactive principles, but the Indian use of the plant as a ritual snuff ingredient is not well recorded or even unlikely: Banisteriopsis, Cannabis, Datura, Ilex guayusa; The Indian use of the plant as a ritual snuff ingredient is confirmed or quite probable, but it is not well established that the plant contains one or more psychoactive principles: Justicia pectoralis, Pagamea macrophylla, Tanaecium nocturnum; The Indian use of the plant as a ritual snuff ingredient is not well recorded, and it is not well established that the plant contains one or more psychoactive principles: Acorus calamus, Capsicum, Macquira sclerophylla, Piper interitum. Part two of the paper discusses the nasal pharmacokinetics and efficacy of possible ritual snuff constituents. The literature yields convincing clinical evidence that atropine, cocaine, nicotine and scopolamine are effective following nasal application, but experimental confirmation of the efficacy of nasal tryptamine alkaloids is still awaited. In self-experiments, 6.4 mg/kg of caffeine produced substantial plasma levels via the nasal route, but 0.5 mg/kg of harmine did not produce measurable plasma levels, when taken as a nasal powder. Without additional experiments, it is difficult to give a definite explanation for this negative result.

Effects of the administration of coca alkaloids on the primary immune responses of mice: interaction with delta 9-tetrahydrocannabinol and ethanol

The effects of cocaine, its metabolites, and other alkaloids from Erythroxylon coca on the primary immune responses of ICR mice to sheep red blood cells (sRBC) and dinitrofluorobenzene (DNFB) were studied. The Jerne hemolytic plaque assay (PFC) was used to evaluate the humoral immune response to sheep red blood cells, and the delayed type hypersensitivity (DTH) response to DNFB was used to study cellular immune responsiveness. Drugs were given in single daily po doses for 5 consecutive days beginning on the day of immunization or 3 days prior to and on Days 3 and 4 after immunization. Inhibition of both PFC and DTH responses occurred at doses of 15 to 60 mg/kg of cocaine and was greatest when fed during immunization. Five other alkaloids also suppressed the PFC and/or DTH response. Cocaine was more suppressive than the six other alkaloids tested. Ethanol (5 g/kg) did not suppress the DTH response and only marginally suppressed the PFC response. delta 9-THC inhibited the PFC response at doses of 10 mg/kg and marginally suppressed the DTH response at doses of 30 mg/kg, but not at other doses ranging from 10 to 90 mg/kg. Coadministration of 5 g/kg ethanol and 15 mg/kg cocaine resulted in 50% antagonism of effects of cocaine on the PFC response and complete antagonism of the suppression of the DTH response, but only if these substances were given during the period of immunization. Like ethanol, delta 9-THC also abolished the inhibitory effects of cocaine on the PFC and DTH response but only if coadministered during the period of immunization. Coadministration of ethanol and delta 9-THC resulted in synergistic inhibition of both DTH and PFC responses.

Analysis of alkaloids in leaves of cultivated Erythroxylum and characterization of alkaline substances used during coca chewing

Several solvents were tested for the extraction of the alkaloids in Erythroxylum coca. The resulting crude extracts were analyzed by gas chromatography--mass spectrometry. Ethanol extraction was found to be the only quantitative method presenting no artifacts. It was established that cocaine and cis- and trans-cinnamoylcocaine were the endogenous alkaloids in E. coca leaves. From the several breakdown compounds arising during long-term extraction with H2SO4 or CHCl3, ecgonine methyl ester was the only alkaloid fully identified; ecgonine methyl ester was tentatively identified on the basis of its mass spectrum fragmentation pattern. Quantification by mass fragmentography of the three endogenous compounds was performed using a stable-isotope dilution technique on individual leaves of single branches of E. coca, E. novogranatense and E. novogranatense var. truxillense. The relative amounts of these alkaloids changed with leaf age as well as between species and varieties. The variation in alkaloid levels between individual leaves was too great to allow the use of the ratio between cocaine and the cinnamoylcocaine levels as a taxonomic marker. The initial pH value of 17 different alkaline substances traditionally used during coca leaf chewing was measured after dissolution in H2O; values ranged between 10.1 and 12.8. Buffer capacity was determined by titration with HCl. Three types of curve shapes were obtained which could correspond to NaOH, Na2CO3 and NaHCO3 titration curves. One sample of alkaline material had no buffer capacity at all. The recovery and breakdown of the cocaine contained in E. coca leaf power was monitored for one hour at various pHs at 37 degrees C. The levels of cocaine and benzoylecgonine did not change by more than 17% at any of the pHs tested (6.0, 9.0 and 11.5). It was concluded that the alkaline substances are mainly responsible for the transformation of the alkaloids to free bases and not for a major hydrolysis of cocaine.