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Pure, Natural Coca Leaf – A Healing Gift Of The Divine Plant


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The Cultivation Of Coca: Field Notes From The 18th Century

Editor’s Note: I’m not sure where these field notes came from, so I can’t cite the source. I found them in a folder on my desktop along with a number of 18th century texts that I had downloaded from archive.org, but failed to record their origin. However, there is enough here of interest that I decided to post without citing a source – something I am normally reluctant to do. These notes offer a detailed look at some interesting and potentially very useful traditional Coca cultivation, harvesting and preparation techniques gathered by this unknown author from contemporary sources in the late 1700’s or early 1800’s.

Botany Of The Coca Plant

Some botanists have considered the characteristic lateral lines of the Coca leaf as nerves. Martins was of the opinion these result from pressure of the margin of the leaf as it is rolled toward the midrib while in the bud, the pinching of the tissue causing the substance of the leaf to be raised, resembling a delicate nerve. The lines have been designated as “tissue folds” but there is no fold in either the epidermis or substance of the leaf. Histologically the lines are formed by a narrow band of elongated cells, which resemble the collenchyma cells of the neighboring epidermis and these doubtless serve to stiffen the blade. The lines have no connection with the veins of the leaf and in transmitted light seem like mere ghostly shadows which vanish under closer search.

Many observers have supposed they had found the original locality of wild Coca. Alcide d’Orbigny describes in his travels, having entered a valley covered with what he supposed to be the wild Coca shrub, but thinking he might be mistaken, he showed the plant to his mule driver, who was the proprietor of a cocal in Yungas, and he pronounced it undoubtedly Coca and gathered a quantity of the leaves. It has been asserted that wild Coca may be found in the province of Cochero, and one of the former governors of Oran, in the province of Salta, on the northern borders of the Argentine Republic, claims to have found wild Coca of excellent quality in the forests of that district. Poeppig also described having found wild specimens, known by the natives as Mama Coca, in the Cerro San Cristobal, near the Huallaga, some miles below Huanueo. These examples closely resemble the shrubs of cultivated Coca collected by Martins in the neighborhood of Ega, Brazil, near the borders of the Amazon, and correspond to the wild specimens commonly found throughout Peru.

In Colombia Humboldt, Bonpland and Kunth described Erythroxylon Hondense as the possible type of the originally cultivated Coca shrub, but there is a difference between the leaves of E. Coca and E. Hondense in the arrangement of their nervures, from which Pyrame de Candolle considers them as entirely distinct species. Andre speaks of Coca in the valley of the river Cauca as in abundance in both the wild and half- wild state, but an excellent authority denies that Coca is found wild in Colombia.  The exact locality where Coca is indigenous in a wild state has, however, never been determined. Though there are many Coca plants growing throughout the montaña outside of cultivation, it is presumed that these are examples where the seeds of the plant have either been unintentionally scattered or else are the remains of some neglected plantation where might have flourished a vigorous cocal under the Spanish reign. There are evidences of these scattered shrubs throughout the entire region where Coca will grow, but there is no historical data to base a conclusion that these represent wild plants of any distinct original variety, while the weight of testimony indicates that they are examples of the traditional plant which have escaped from cultivation.

Traditional Coca-Growing Regions

Although the heart of the habitat of Coca is in the Peruvian montaña from 7° S., north for some ten degrees, the shrubs are found scattered along the entire eastern curve of the Andes, from the Straits of Magellan to the borders of the Caribbean Sea, in the moist and warm slopes of the mountains, at an elevation from 1,500 to 5,000 and even 6,000 feet, being cultivated at a higher altitude through Bolivia than in Peru. Throughout this extent there are to be seen large plantations and many smaller patches where Coca is raised in a small way by Indians who come three or four times a year to look after their crop. In some localities, through many miles, these cocals cover the sides of the mountains for thousands of feet. During the Incan period the centre of this industry was about the royal city of Cuzco, and at present the provinces of Caravaya and of Sandia, east of Cuzco, are the site of the finest variety of Peruvian grown Coca. In this same region there grows coffee, cacao, cascarilla, potatoes, maize, the sugar cane, bananas, peaches, oranges, paltas, and a host of luscious fruits and many valuable dyes and woods.

There are still important Coca regions about Cuzco, and at Paucartambo and in several Indian towns along the Ilnanuco valley, situated in the very heart of the northern Montaña and noted for its coffee plantations. At one time this region was accredited with supplying Coca for all Peru, which probably meant the mining centres of Huancavelica—formerly more prominent than at present—and Cerro de Pasco, where the mines are still extensively worked. There are fine cocals at Mayro, on the Zuzu Piver, and at Pozuso—which are German colonies; at the latter place is located the laboratory of Kitz, one of the largest manufacturers of crude cocaine, whose product supplies some of the important German chemical houses. Still further to the northwest—in Colombia, there are a number of small plantations along the valley of Yupa, at the foot of the chain of mountains which separates the province of Santa Marta de Maracaibo, at the mouth of the Magdalena River. Eastward from the montaña Coca is cultivated near many of the tributaries of the Amazon, and through some portions of Brazil, where it is known as ypadu. The Amazonian plant is not only modified in appearance, but the alkaloidal yield is inferior.

Ideal Coca-Growing Conditions

The temperature in which Coca is grown must be equable, of about 18° C. (61.4° F.). If the mean exceeds 20° C. (68° F.), the plant loses strength and the leaf assumes a dryness which always indicates that it is grown in too warm a situation, and though the leaves may be more prolific, they have not the delicate aroma of choice Coca. It is for the purpose of securing uniform temperature and appropriate drainage that Coca by preference is grown at an altitude above the intense heat of the valleys, and where it is virtually one season throughout the year, the only change being between the hot sun or the profuse rains of the tropical montaña. As the temperature lowers with increase of altitude, when too great a height is reached the shrub is less thrifty and develops a small leaf of little market value, while as only one harvest is possible the expense of cultivation is too great to prove profitable.

Even close to the equator, in the higher elevations, there is always danger from frost, and for this reason some of the cocals about Huanuco have at times suffered serious loss. All attempts at Coca cultivation on a profitable scale near to Lima have failed not only because of the absence of rain, but because the season’s changing is unsuited.

A peculiar earth is required for the most favorable cultivation of Coca, one rich in mineral matter, yet free from limestone, which is so detrimental that even when it is in the substratum of a vegetable soil the shrub grown over it will be stunted and the foliage scanty. While the young Coca plants may thrive best in a light, porous soil, such as that in the warmer valleys, the full grown shrub yields a better quality of leaf when grown in clay. The red clay, common in the tropical Andes, is formed by a union of organic acids with the inorganic bases of alkaline earths, and oxides – chiefly of iron which in a soluble form are brought to the surface by capillarity.

These elements enter the Coca shrub in solution through its multiple fibrous root, which looks like a veritable wig. The delicate filaments are extended in every direction to drink in moisture, and as these root-hairs enter the interspaces of the soil, the particles of which are covered with a film of water, absorption readily takes place. The clay soil of the montaña affords this property in a high degree, while the hillside cultivation admits of an appropriate drainage the interspaces without which the delicate root would soon be rotted. As the water is absorbed from the soil, a flow by capillarity takes place to that point, and so the Coca root will drain a considerable space.

It is possible a metallic soil may have some marked influence on the yield of alkaloid. At Phara, where the best Coca leaves are grown, the adjacent mountains are formed of at least two per cent, of arsenical pyrites, a fact which is noteworthy because this is the only place in Peru where the soil is of such a nature. Most of the soil of the Andean hills where the best Coca is grown, originates in the decay of the pyritiferous schists, which form the chief geological feature of the surrounding mountains. This, commonly mixed with organic matter and salts from the decaying vegetation, or that of the trees burned to make a clearing, affords what might be termed a virgin earth – terre franche ou normale – which requires no addition of manures for invigoration. In the  conservatory it has been found, after careful experimentation, that a mixture of leaf mould and sand – terre de bruyere – forms the best artificial soil for the Coca plant.

Aside from an appropriate soil that is well drained, there is another important element to the best growth of Coca, and that is a humid atmosphere. Indeed, in the heart of the Montaña it is either hazy or drizzling during some portion of the day throughout the year, the intense glare of the tropical sun being usually masked by banks of fog, so that it would seem that one living here is dwelling in the clouds. At night the atmosphere is loaded with moisture and the temperature may be a little lower than during the day, though there is usually but a trifling variation day after day.

Coca Cultivation On A Cocal

The natural life of the Coca shrub exceeds the average life of man, yet new Cocals are being frequently set out to replace those plants destroyed through accident or carelessness. The young plants are usually started in a nursery, or almaciga, from seeds planted during the rainy season, or these may be propagated from cuttings. In the conservatory slips may be successfully grown if care is taken to retain sufficient moisture about the young plant by covering it with a bell glass.

The birds are great lovers of Coca seeds, and when these are lightly sown on the surface of the nursery it is necessary to cover the beds at night with cloths to guard against “picking and stealing.” Before sowing the seeds are sometimes germinated by keeping them in a heap three or four inches high and watering them until they sprout. They are then carefully picked apart and planted either in hills or the seeds are simply sown on the surface of the ground, and from that they take them up and set them in other places into earth that is well labored and tilled and made convenient to set them in. There is commonly over the beds of the nursery a thatched roof – huasichi – which serves as a protection to the tender growing shoots from the beating rain or melting fierceness of the occasional sun. The first spears are seen in a fortnight, and the plants are carefully nourished during six months, or perhaps even a year until they become strong enough to be transplanted to the field.

As a rule, all plants that are forty or fifty centimetres high (16 to 20 inches) may be set out, being placed in rows as we might plant peas or beans. In some cases, they are set in little walled beds, termed aspi, a foot square, care being taken that the roots shall penetrate straight into the ground. Each of these holes is set about with stones to prevent the surrounding earth from falling, while yet admitting a free access of air about the roots. In such a bed, three or four seedlings may be planted to grow up together, a method which is the outgrowth of laziness, as the shrubs will flourish better when set out singly. Usually the plants are arranged in rows, termed uachas, which are separated by little walls of earth – umachas – at the base of which the plants are set. In some districts the bottle gourd, maize, or even coffee, is sown between these rows, so as to afford a shield for the delicate shoots against sun or rain. At first the young plants are weeded – mazi as it is termed – frequently, and in an appropriate region there is no need for artificial watering: but the Coca plant loves moisture, and forty days under irrigation will cover naked shrubs with new leaves, but the quality is not equal to those grown by natural means.

In from eighteen months to two years the first harvest, or mitta, which literally means time or season—is commenced. The leaves are considered mature when they have begun to assume a faint yellow tint, or better—when their softness is giving place to a tendency to crack or break off when bent, usually about eight days before the leaf would fall naturally. This ripe Coca leaf is termed by the Indians cacha.

The Coca shrub, growing out of immediate cultivation, will sometimes attain a height of about twelve feet, but for the convenience of picking, cultivated plants are kept down to less than half that height by pruning – huriar or ecuspar – at the time of harvesting, by picking off the upper twigs, which increases the lateral spread of the shrub. The first harvest—or rather preliminary picking, is known as quita calzon, from the Spanish quitar—to take away, and calzon—breeches. As the name indicates, it is really more of a trimming than what might be termed a harvest, and the leaves gathered at this time have less flavor than those of the regular mittas. Each of the harvests is designated by name—which may vary according to the district. The first regular one in the spring – mitta de marzo – yields the most abundantly. Then, at the end of June, there is commonly a scanty crop known as the mitta de San Juan – the harvest of the festival of St. John – while a third, following in October or November, is the mitta de Todos Santos—the harvest of all saints.

Usually the shrubs are weeded only after each harvest, and there seems to be a prejudice against doing this at other times, though if the cocals are kept clear the harvest may be anticipated by more than a fortnight. Garcilasso tells how an avaricious planter, by diligence in cultivating his Coca, got rid of two-thirds of his annual tithes in the first harvest.

Harvesting & Curing Coca Leaf

Picking exerts a beneficial influence on the shrub, which otherwise would not flourish so well. The gathering – palla – is still done by women and children – palladores as they are termed – just as was the custom during the time of the Incas, though the Colombians will not permit women to take part in the Coca cultivation at any time.

Many writers have spoken of the extreme care with which the leaves are picked or pinched from the shrub, one by one; but to a casual observer the gathering seems to be done far more carelessly. The collector squats down in front of the shrub, and taking a branch strips the leaves off with both hands by a dexterous movement, while avoiding injury to the tender twigs. The pickers must be skilled in their work, for not only a certain knack, but some little force is requisite, as is shown by the wounds occasioned to even the hard skin of the hand of those who are accustomed to the task.

The leaves are collected in a poncho or in an apron of coarse wool, from which the green leaves – termed matu – are emptied into larger sacks –  materos – in which they are conveyed to the drying shed – matucanclia. Four or five expert pickers in a good cocal can gather a cesta—equivalent to a bale of twenty-five pounds, in a day.

Harvesting is never commenced except when the weather is dry, for rain would immediately spoil the leaves after they have been picked, rendering them black in color and unsalable, a condition which the Indians term Coca gonupa, or yana Coca.

Coca when gathered is stored temporarily in sheds matuhuarsi, which open into closed courts, the cachi, or matupampa, and the contents of these warehouses indicate the prosperity of the master of the cocal.  In the drying yards of these places the leaves are spread in thin layers two or three inches deep, either upon a slate pavement – pizarra – or simply distributed upon a hard piece of clear ground of the casa de hacienda. The closest guardianship must now be maintained over the leaves during the process of drying, and on the slightest indication of rain they are swept under cover by the attendants with the greatest rapidity.

Drying may be completed within six hours in good weather, and when properly dried under such favorable conditions, the leaf is termed Coca del dia and commands the highest price. A well cured mature Coca leaf is olive green, pliable, clean, smooth and slightly glossy, while those which are old or are dried more slowly assume a brownish green and are less desirable. After drying, the leaves are thrown in a heap, where they remain about three days while undergoing a sort of sweating process. When this commences the leaf is crisp, but sweating renders it soft and pliable. After sweating the leaves are again sun dried for a half hour or so, and are then ready for packing. If the green leaves cannot be immediately dried, they may be preserved for a few days if care be taken not to keep them in heaps, which would induce a secondary sweating or decomposition and give rise to a musty odor, termed Coca cespada, which clings even to the preparations made from such leaves.

The refinement of curing maintains a certain amount of moisture in the leaf, together with the peculiar Coca aroma, and it is exact discernment in this process which preserves the delicacy of flavor. When drying has been so prolonged as to render the leaf brittle and without aroma, the quality of Coca is destroyed. It has been suggested that an improvement might be made in drying through the use of sheds, where the leaves could be exposed in layers to an artificial heat, and a current of dry air, after the manner of the secaderos used in Cuba for drying coffee. But whether because of an unwillingness to adopt new methods, or because of some peculiar influence of the atmosphere imparted to the leaf in the native way of drying, all attempts to employ artificial methods have proved unsatisfactory.

Care & Preparation Of Coca Seeds

When the fruit has formed it changes color in ripening, through all the hues from a delicate greenish yellow to a deep scarlet vermilion, and upon the same shrub there may be a number of such colorations to be seen at one time. Monardes, writing centuries ago, said: ”The fruit is in the form of a grape, and as the fruit of the myrtle is reddish when it is ripening, and about of the same dimensions—when attaining its highest maturity becoming darker black.” I was going to say that the fruit resembles the smallest of oval cranberries, both in color and in shape, for I at one time found some little cranberries which appeared so much like the Coca fruit as to seem almost identical; but all cranberries are not alike, and there has already been too much confusion in hasty comparison, so I shall reserve my description for the more technical details. The fruit is gathered while yet scarlet during the March harvest, but if it is permitted to remain on the bush it becomes dark brown or black and shrivels to the irregular lobing of the contained nut.

In selecting the seeds care is taken to cast aside all fruit that is decayed, the balance being thrown into water, and those which are light enough to float are rejected as indicating they have been attacked by insects. The balance of the seeds are then rotted in a damp, shaded place, to extract the seed, which is washed and sun dried. When it is desired to preserve these any length of time the fruit is exposed to the hot sun, which dries the fleshy portion into a protective coating. But the seeds do not keep well. In Peru, perhaps they will retain germinating power for about fifteen days, while those from plants grown in the conservatory must be planted fresh, when still red, for if allowed to dry they become useless.

Natural Enemies Of The Coca Plant

With every detail to cultivation which tradition has inspired, the Coca crop is not always secure, for the cocals are subject to the attacks of several pests, which, while a constant source of annoyance may at times seriously damage the shrubs. Below an altitude of four thousand feet there is the iilo, a little butterfly, which during a dry spell deposits its eggs, and as the grubs develop they devour the younger leaves. In the older cocals an insect called mougna sometimes introduces itself into the trunk of the shrub and occasions its withering. M. Grandidier speaks of a disease termed cupa, or cuchupa, in the valley of the Santa Marta, which has destroyed an entire crop within eight days. From an attack of this not only the immediate leaf is rendered small and bitter, but during the following year the shrub remains unproductive, and a gall-like excrescence is developed termed saran moello—seeds of gall. Some cultivators at the first indication of this disease prune the affected twigs and so succeed in raising a new crop by the next harvest.

The ant, cuqui, which is a great pest through all the montaña, is a dangerous evil to the Coca plant. It not only cuts the roots, but disintegrates the bark and destroys the leaves, and in a single night may ruin an entire plantation. In fact, the sagacity of the traditional ant is outdone by these pests. Some of them are capable of carrying a kernel of corn, and an army of them will run off with a bag of corn in a night, kernel by kernel, making a distinct trail in the line of their depredations. They build their nests of leaves, twigs and earth, and even construct an underground system of channels to supply their hillocks with water. It is extremely difficult to keep them out of a cocal, as they will burrow under the deepest ditches, and the only method of being free from them is to destroy their hills wherever they are found.

Another enemy to the shrub is a long bluish earthworm, which eats the roots and so occasions the death of the plant. Then a peculiar fungus, known as taja, forms at times on the tender twigs, occasioned by injury or from poor nutrition.

Aside from these pests, there are a number of weeds which are particularly injurious to Coca, among which are the Panicuni platicaule, P. scandens, P. decumheus, Pannisetum Perurianum, Drimaria, and Pteris arachnoidea.”’ These plants grow rapidly and take so much nourishment from the soil as to destroy the nutrition of the Coca shrub. For a similar reason the planting of anything between the rows of Coca is now abandoned.


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Wild Coca Species Are Broadly Distributed – Not Just In The Andes!

Editor’s Note: This research paper is valuable for an understanding of the Coca plant in several important ways. First, it makes very clear that the alkaloid Cocaine along with other beneficial alkaloids present in varying concentrations in dozens of species of genus Erythrolylum, not just in the Coca plant of the Andes most closely associated with Cocaine production. These Cocaine and alkaloid-rich wild species are broadly distributed – principally but not exclusively in South America.

(An interesting aside – not mentioned by the authors of this study – is that in the 1800s there were dedicated efforts to cultivate Coca plants in many parts of the world including Puerto Rico, the Dominican Republic, Costa Rica, Mexico, Java, Algeria, and the Western US, so it is highly likely that if one looked carefully one would find wild, escaped descendants of the original plantings in at least some of those places today.)

Another thing that makes this research interesting is that the experiments were conducted on leaves of wild Erythroxylum species used botanical samples collected many years ago and kept since in collections in various research institutions. In other words, the samples tested were 30-50 years old!

The fact that the researchers found Cocaine in dozens of species by examining specimens that old begs the question – what is the Cocaine and beneficial alkaloid concentration in fresh specimens of these wild species? Since it is well-known among indigenous Andean people that fresh Coca leaves are superior to even year-old leaves, you have to think that fresh leaves from some of the wild species identified in this study would make a very nice Coca Leaf tea.

But the real “Wow!” factor to me in this research is that of the dozens of wild species of the genus Erythroxylum scattered around the world at least some have most or possibly all of the alkaloid and other plant constituents that provide the well-documented health benefits of the Erythroxylon Coca of the Andes. While the authors of this study found that almost all of the wild species that contained Cocaine had very small amounts, you have to wonder what a little TLC (tender loving cultivation) would do to the alkaloid content of at least some of these wild species? Who knows – this news might just inspire a whole new generation of PharmaBotanists to go forth and seek out these apparently 100% legal plants and in the process drive the DEA stark raving bonkers – not that they aren’t already.

Which brings me to another very valuable aspect of this research. The scientists not only tested decades-old leaves of wild species, they also tested contemporary Coca Leaf Tea products from Bolivia and Peru. Their findings should encourage anyone who is interested in using these readily available (in Bolivia and Peru) commercial products for dealing with health issues because the researchers conclude that some of the products sold in Bolivia and Peru are “pure Coca leaf” and others, even the “de-cocainized” products that are sold in the US (check Amazon), not only are not completely “de-cocainized” but they appear to still have a leaf chemistry profile that indicates they should be at least minimally effective for some therapeutic uses. The Teas available in the US are definitely not anywhere as effective as pure, natural whole Coca leaf – but they are not altogether useless either. And (some of) the commercial Coca Leaf teas produced and sold in both Bolivia and Peru are pure, natural Coca Leaf – the way the great spirit of Mama Coca made them.

Final comment – although I have included information from the original article on the testing procedures the scientists used in working on all of the Wild Coca species, I have left out their extensive data tables for the sake of both brevity and simplicity. However I have included their valuable list of references for readers who might like to follow up.

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Cocaine Distribution In Wild Erythroxylum Species

Stefan Bieri, Anne Brachet, Jean-Luc Veuthey, Philippe Christen (Corresponding author. Fax: +41 22 379 33 99, E-mail address: philippe.christen@pharm.unige.ch (P. Christen).

Laboratory of Pharmaceutical Analytical Chemistry, School of Pharmaceutical Sciences EPGL, University of Geneva, 20 Bd d’Yvoy, 1211 Geneva 4, Switzerland

Battelle, Agrochemical Product Development, 7 Route de Drize, 1227 Carouge-Geneva, Switzerland

Received 30 May 2005; received in revised form 10 August 2005; accepted 16 August 2005

Available online 30 September 2005

Abstract
Cocaine distribution was studied in leaves of wild Erythroxylum species originating from Bolivia, Brazil, Ecuador, Paraguay, Peru, Mexico, USA, Venezuela and Mauritius. Among 51 species, 28 had never been phytochemically investigated before. Cocaine was efficiently and rapidly extracted with methanol, using focused microwaves at atmospheric pressure, and analysed without any further purification by capillary gas chromatography coupled to mass spectrometry. Cocaine was reported for the first time in 14 species. Erythroxylum laetevirens was the wild species with the highest cocaine content. Its qualitative chromatographic profile also revealed other characteristic tropane alkaloids. Finally, its cocaine content was compared to those of two cultivated coca plants as well as with a coca tea bag sample.

© 2005 Elsevier Ireland Ltd. All rights reserved.

Keywords: Erythroxylaceae; Erythroxylum; Erythroxylum laetevirens; Cocaine; Tropane alkaloids; Gas chromatography; Mass spectrometry; Focused microwave assisted extraction

Introduction

The last 30 years have seen an increasing interest in cocaine analysis resulting from its expanding illicit use in Western Europe and North America. Regardless of the importance of cultivated coca plants from an economical point of view, these species always played a key role for South American natives (Grinspoon and Bakalar, 1981; Naranjo, 1981; Schultes, 1981; Plowman, 1984a).

Coca chewing in South America has persisted from ancient times, but is still poorly understood from many points of view. This traditional habit is largely considered
noxious by many regulatory authorities.

The family Erythroxylaceae is composed of four genera: Aneulophus, Erythroxylum, Nectaropetalum and Pinacopodium (Hegnauer, 1981). The genus Erythroxylum, by far the most well know genus of the family comprises roughly 230 species of tropical trees and shrubs, which are widely distributed in South America, Africa and Madagascar (Plowman and Hensold, 2004).

In 1907, Schulz divided this genus into 19 sections, providing a useful scheme for comparative phytochemical considerations. Erythroxylum and more particularly Erythroxylum coca and Erythroxylum novogranatense, as well as their varieties, is the only natural source of cocaine (Plowman, 1984b).

Even if some attention has been focused on non-cultivated Erythroxylum species for the possible presence of cocaine, systematic investigation of the genus is still incomplete and several species used in traditional medicine remain unknown (Evans, 1981).

Aynilian et al. (1974) reported the concentration of cocaine in herbarium specimens of seven Erythroxylum species. Holmstedt et al. (1977) analysed 62 samples of 13 tropical
South American species by capillary gas chromatography coupled to mass spectrometry (GC-MS). Cocaine was found only in the leaves of two species, Erythroxylum coca and Erythroxylum novogranatense, but no measurable amount of cocaine was detected in any of the other 11 species. Subsequently, Plowman and Rivier (1983), using more sensitive assays, detected trace amounts of cocaine in 13 neotropical wild Erythroxylum species
representing five sections of the genus. Besides, they found that two species from Venezuela, namely Erythroxylum recurrens and Erythroxylum steyermarkii, contained cocaine amounts comparable to those found in cultivated species.

This study is part of a large investigation of the genus Erythroxylum for tropane and related alkaloids (Brachet et al., 1997, 2002; Christen et al., 1993, 1995; Brock et al., 2005).

We report here on the specific investigation of cocaine in 51 wild species. Due to the presence of an appreciable amount of cocaine, Erythroxylum laetevirens was qualitatively investigated for the presence of other tropane alkaloids and its chromatographic profile was compared to those of two cultivated species, together with
a coca tea bag sample.

2. Materials and methods

2.1. Plant material and chemicals

Most species were collected in South America between 1979 and 1984 by the late T. Plowman and kindly provided by Dr. Laurent Rivier (Lausanne, Switzerland). Two species originating from sites other than South America were also included in this study, namely Erythroxylum areolatum from the Bahamas (USA) and Erythroxylum macrocarpum from Mauritius. A voucher specimen of all plants is deposited at our Institute.

For each species, only the leaves were analysed. Dry plant material was ground to a fine homogenous powder by a ballmill (MM 200 RETSCH, Switzerland) and finally sieved to an average particle size of less than 125 m.

Cocaine hydrochloride (COC) and Methadone hydrochloride (MET) were obtained from Siegfried Handel (Zofingen, Switzerland) and H¨ansler (Herisau, Switzerland), respectively.

2.2. Extraction procedure

Extractions were performed using focused microwaves at atmospheric pressure at a frequency of 2450MHz using a Soxwave 3.6 apparatus (Prolabo, France) with a programmable heating power. Typically, 100 mg of powdered plant material was placed into a 20mL quartz extraction vessel and hydrated with 10L of water prior to the addition of 5mL methanol.

The extraction was carried out at 125W for 30 seconds. Each extract solution was filtered on a 0.45 mm PTFE filter (Brachet et al., 2002). Solutions obtained from wild species were evaporated to dryness and taken up in 1mL methanol containing 10 ppm internal standard (methadone), while solutions from cultivated species were diluted four times with methanol. All samples were analysed by GC-MS without any further purification.

2.3. Gas chromatography

GC-MS analyses were carried out using a Hewlett-Packard 5890 series II chromatograph coupled to a HP 5972 mass selective detector (Agilent Technologies, Palo Alto, CA, USA). The mass detector operated in the electron impact ionization mode at 70 eV. Injections were performed in the splitless mode at 250o C with a splitless period of 60 s and with purge and septum purge flow rates of 30 and 3 mL/min, respectively.

Injections of 1 L were carried out with a HP 6890 series fast automatic liquid sampler
(Agilent Technologies). A laminar liner (Restek, Bellefonte, PA, USA) was used as well as a standard syringe with a 42mm long needle and a cone tip. Helium was used as carrier gas and operated in the constant flow mode (1 ml/min).

For qualitative analysis, a HP5-MS column, 30 mm×0.25 mm i.d.× 0.25 mm
film thickness was used with an initial oven temperature of 70 ◦C (1 min hold) and a linear temperature program from 70 to 285o C at 5 o C/min and hold at the final temperature for 15 min. Spectra were recorded in the mass range 30–500 Th with 1.3 scan/s and the MS transfer line was set at 280 o C.

For quantitative cocaine analysis, the oven was initially set at 70 ◦C (1 min hold) and linearly increased to 285 o C (5 min hold) at 30 ◦C/min. GCMS (SIM mode) was performed using the selective ion 303 Th (molecular ion of cocaine), the qualifier ion 272 Th and the target ion 182 Th (base peak of cocaine). Methadone (MET) was
used as internal standard with target ion 294 Th (molecular ion) and qualifier ion 72 Th (base peak of methadone). In order to enhance sensitivity, the potential of the electron multiplier was increased by a 400V increment for a period of time of 2 min which included elution of the internal standard and cocaine.

2.4. Quantification

Standard calibration curve was obtained with cocaine solutions at seven concentration levels between 0.1 and 100 ppm (0.1, 0.5, 1, 5, 25, 50 and 100 ppm) containing a fixed concentration (10 ppm) of methadone. Quantitative determination was based on the peak area ratio of the target ions of cocaine over methadone. A correlation coefficient of 0.9992 was obtained.

The relative standard deviations (R.S.D.) for six consecutive injections with a cocaine standard solution at 5 ppm was inferior to 5%, and inferior to 10% at 0.1 ppm, corresponding to the limit of quantification (LOQ). For any concentration level, the
three cocaine ions were detected at the corresponding elution time (between 9.55 and 9.57 min).

Cocaine was considered to be present in a species, but not quantified (NQ) when ions 182 and 303 Th were detected with a signal to noise ratio of at least 2. When the target ion 182 Th was not detected, the symbol ND was used, meaning that no cocaine
was present.

3. Results and discussion

Before any discussion of the results, it is important to emphasize that the time elapsed between plant harvesting and analysis is between 20 and 25 years. Since it is believed that a cocaine leaf content may vary with time, the quantitative results reported should be viewed from that perspective despite the fact that the preservation of cocaine in Erythroxylum coca leaves has been shown in 44 year-old herbarium samples (Aynilian et al., 1974).

A straightforward sample preparation method involving focused microwave-assisted extraction (FMAE) was used as already described by Brachet et al. (2002). This procedure was particularly well suited for mass limited samples, as it required no more than 100 mg of fine powdered plant material. Indeed, sample amounts of the various examined species at our disposal varied between a few hundred milligrams and a hundred and fifty grams. Furthermore, this method was extremely rapid (30 s), required low amount of organic solvent (5 mL) and thus allowed the extraction of numerous samples in a short period of time. In addition, it is environmentally friendly and does not necessitate additional sophisticated sample treatment before analysis.

After extraction, all of the investigated samples were qualitatively and quantitatively analysed by GC-MS in scan and SIM modes, respectively. The leaves of 51 Erythroxylum species belonging to seven different sections as described by Schulz (1907) were examined for their cocaine content. Among them, 28 species had not been
investigated previously. According to the age of the investigated plant material and due to the low cocaine content, concentration ranges rather than exact concentrations are reported.

Four domains, expressed in percentage of cocaine per gram dry mass, have been defined, namely: (++++) >0.005%; (+++) 0.001–0.005%; (++) 0.0005–0.001%; (+) 0.0001–0.0005%. The LOQ of the method turned out to be 0.0001% of cocaine per gram dry leaf. Retention time repeatability on the target ion (182 Th) was excellent (R.S.D. = 0.01%, n = 6) considering the high oven temperature program rate used for quantitative analyses.

Fig. 1 shows the extracted ion profiles in the case of Erythroxylum argentinum, which was the wild species with the lowest quantified cocaine content. It demonstrates the specificity of the method, which requires the simultaneous presence of the three cocaine ions, together with the precise retention time.

Cocaine was detected in 23 of the 51 species examined. All the investigated sections except one (Pachylobus) contained at least one cocaine-producing species. This
suggests, as indicated by previous studies (Aynilian et al., 1974; Plowman and Rivier, 1983), that cocaine is widely distributed among the genus Erythroxylum, irrespective of the sections.

Fourteen species are reported to contain cocaine for the first time – Erythroxylum amazonicum, Erythroxylum citrifolium, Erythroxylum laetevirens, Erythroxylum argentinum, Erythroxylum cumanense, Erythroxylum densum, Erythroxylum frangulifolium, Erythroxylum subrotundum, Erythroxylum cuneifolium, Erythroxylum divaricatum, Erythroxylum gonocladum, Erythroxylum andreii, Erythroxylum aturense, and Erythroxylum confusum.

Among them, Erythroxylum laetevirens, a shrub with pale-greenish flowers and green fruits, was the wild species with by far the highest cocaine content (0.011% dry weight). Thus, its alkaloid profile was accurately determined and compared with those of two cultivated Erythroxylum coca species, as well as with a “Mate de coca” commercially available on the market in La Paz in Bolivia.

Quantitative results showed that even if the cocaine content in Erythroxylum laetevirens was markedly higher than in all the other investigated wild species, it was nonetheless much lower than in the “Mate de coca”, as well as in the cultivated species. In the literature, it has been reported that in these species, the lowest cocaine content was found in the Ipadu variety (0.11–0.41%) and the highest content in the Truxillense variety (0.42–1.02%), while the cocaine content in the Novogranatense variety ranges from 0.17 to 0.76% (Holmstedt et al., 1977; Plowman and Rivier, 1983). Our results are in good agreement with these values and suggest that the “Mate de coca” probably consists
of coca leaves, but not from the Ipadu variety (Plowman, 1981; Schultes, 1981).

According to Engelke and Gentner, 1991, herbal tea bags sold under the name “Health Inca Tea” or “Mate de Coca” are commercially available since 1981 in Peru. The authors
mentioned that the investigated tea bags were produced and packed in Peru from the leaves of Erythroxylum novogranatense var. truxillense by a national enterprise. Even if the product was claimed to be decocainized, the percentage of cocaine present in the plant tissue raised up to 0.37%, corresponding to about 3.7 mg of cocaine per tea bag.

Similarly, Jenkins et al. (1996), analysed coca tea bags from Peru and Bolivia and indicated that cocaine, benzoylecgonine, ecgonine methyl ester and trans-cinnamoylcocaine were present in variable quantities.

After exhaustive extraction, they found an average cocaine content of roughly 5mg per tea bag consisting of 1 g plant material. When they prepared tea according to the labelling
instructions, an average of about 4mg cocaine was found per cup. These results were in good agreement with other investigations (Rivier, 1981; El Sohly et al., 1986; Siegel et al., 1986; Jackson et al., 1991). The cocaine content in the “Mate de coca” measured in the present study (0.60%), together with the qualitative chromatographic profile, indicate that the investigated tea bags consisted of basically pure coca leaves

Finally, as Erythroxylum laetevirens had not been investigated previously, a qualitative chromatographic profile of its alkaloid content was carried out and compared with those of cultivated coca species. All chromatographic profiles displayed a similar tropane alkaloid pattern. Indeed, hygrine, anhydro-ecgonine methyl ester, ecgonine methyl ester, cocaine, and two characteristic cinnamoylcocaines were unambiguously identified in all samples. The material that appeared between 20 and 27 min in all chromatographic profiles consisted mainly of fatty acids.

4. Conclusions

In the present study, the leaf samples of 51 different Erythroxylum species were investigated for their cocaine content. Twenty-eight species had not been examined previously and cocaine was detected in 23 wild Erythroxylum species. Cocaine content was less than 0.001% for all wild species, except for Erythroxylum laetevirens in which a 10 times higher amount was determined. The qualitative chromatographic profile of the
latter species was very similar to that of cultivated coca species.

In particular, the characteristic cinnamoylcocaines were present. Comparison of GC profiles and quantitative results showed that the so-called “Mate de coca”, also known as “Health Inca tea”, was mainly composed of pure coca leaves. Consequently, the
consumption of coca tea will result in ingestion of varying amounts of cocaine, together with other related tropane alkaloids.

Before any overall chemotaxonomic conclusions are drawn regarding the occurrence of cocaine throughout the genus, further phytochemical investigations on more species are required. It appears from the present study that Cocaine, even in trace amounts is not specifically produced by species belonging to a single section of the genus. Rather, it is widely distributed and thus cannot be used as a specific marker for the genus.

Besides classical botanical or chemotaxonomical approaches, some recent progress has been made in using DNA profiling to characterize the cocaine-producing species (Johnson et al., 2003). This technique, applied to the whole genus, should significantly
help to revise the classification of the species within the Erythroxylum genus.

Acknowledgements

The authors are indebted to Dr. L. Rivier who kindly provided the samples collected by the late Dr. T. Plowman, and who encouraged us to pursue this phytochemical investigation on the Erythroxylum genus.

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