The primary focus of this project has been the ethnobotany of medicinal plants used on the north coast of Peru.

Fieldwork for the present study started in the markets of Trujillo (Mayorista and Hermelindas) and Chiclayo (Modelo and Moshoqueque) in 2001.

Precedents for this study have been established by the late 17^th-century plant collections of Bishop Baltasar Jaime Martinez de Compañón 14, ethnoarchaeological analysis of the psychedelic San Pedro cactus 15, curandera depictions in Moche ceramics 16, and research on the medicinal plants of Southern Ecuador 1718 used in a field guide on the medicinal plants of the region 19.

Considerable progress has been made in the overall taxonomic treatment of the flora of Peru over the last few decades 20. However, while the Amazon rainforests have received a great deal of scientific attention, the mountain forests and remote highland areas are still relatively unexplored. The first floristic studies were conducted in the 1920's 21, followed by decades without any further research activity. Until the late 1990s little work had been done on vegetation structure, ecology, and ethnobotany in the mountain forests and coastal areas of the North.

In spite of the fact that Northern Peru is what Peruvian anthropologist Lupe Camino calls the "health axis," of the old Central Andean culture area stretching from Ecuador to Bolivia 22, little ethnobotanical and ethnomedical research has been published on the rich shamanic lore found here. The traditional use of medicinal plants in this region, which encompasses in particular the Departments of Piura, Lambayeque, La Libertad, Cajamarca, and San Martin (Fig. 1) dates as far back as the first millennium B.C. (north coastal Cupisnique culture) or at least to the Moche period (AC 100–800, Fig. 2), with healing scenes and healers frequently depicted in ceramics.

Healing altars (mesas) in Northern Peru often follow the old tradition by including all kinds of "power objects," frequently with a "pagan" background. Objects such as seashells, pre-Columbian ceramics, staffs, stones, etc. are very common on Peruvian mesas, and are blended with Christian symbols such as crosses and images of saints (Figs. 2, 3 and 4).

Treatments are most often performed in the homes of the individual healers, who normally have their mesas (healing altars) set up in their backyards. Healers also treat patients at altars and consultation chambers (consultorios) at their homes, at sacred sites in the countryside, or at sacred lagoons high up in the mountains. A curing ceremony normally involves purification of the patient by orally spraying blessed and enchanted herbal extracts on the whole body to fend off evil spirits and by nasal ingestion of tobacco juice and perfumes.

Patients are cleansed by spraying them with holy water and perfumes, and baths or "Spiritual Flowerings" (baños de florecimiento) are very important components of the healing tradition. In most cases the cleansing of the patients involves the nasal ingestion of tobacco juice and perfumes, and extracts of Jimson weed (Datura ferox), Brugmansia spp., and tobacco are used to purify the patients.

While the incantations used by healers during their curing sessions include Christian components (e.g. the invocation of Christ, the Virgin Mary, and any number of saints), references to Andean cosmology (e.g., to the apus or the spirits of the mountains) are very common. The use of guinea pigs as diagnostic instruments is standard in Northern Peru.

Early ethnobotanically oriented studies focused mainly on the famous "magical" and "mind altering" flora of Peru. A first study on "cimora" – another vernacular name for the San Pedro cactus (Echinopsis pachanoi), dates back to the 1940's 23. The first detailed study on a hallucinogen in Peru focused also on San Pedro, and tree datura (Brugmansia spp.) 242526. A variety of works on these species followed 27282930. Coca (Erythroxylon coca) also attracted early scientific attention 3132333435, as did the Amazonian Ayahuasca (Banisteriopsis caapi) 36373839. Chiappe and Millones 40 were the first to attempt an overview on the use of hallucinogens in shamanistic practices in Peru. More comprehensive accounts are provided by 414243.

In his classical study of "Uña de Gato", Peru's leading advocate for traditional medicine, and former director of the Instituto Nacional de Medicina Tradicional del Ministerio de Salud, Fernando Cabieses [44, p 34, 45–47] points out that the work of the Peruvian scholars Hermilio Valdizán and Angel Maldonado 21 was the pioneering effort in studying traditional medicine, leading to the emergence of medical anthropology nearly five decades later. In the interim the botanical exploration of the Peruvian flora and medicinal plants in particular included studies by Yakovleff 45 Weberbauer 46, Towle 47 and Valdivia 48. Most authors 49505152535455 focused on Quechua herbalism of the Cusco area. Other comprehensive studies centered on the border region of Peru and Bolivia around Lake Titicaca 56575859 and the Amazon 6061626364. Northern Peru, in contrast, has always been in the shadow of these more touristically important regions, and very few studies have been conducted to date 65666768.

During the 1970s the World Health Organization (WHO) was very proactive in advocating the integration of traditional medicine into public health programs in Third World countries. This culminated in the Alma Ata Declaration of 1978, which proclaimed "health for all in the year 2000" 69. Cabieses 44 describes his struggles to implement the UN tenets in Peru, together with Carlos Alberto Seguin 7071 who advocated the incorporation of traditional folk psychotherapy into the modern institutional framework. In 1979 they organized the First World Congress of Traditional Medicine. As a result, Cabieses and Seguin were nearly expelled from the prestigious Colegio Médico del Perú, the counterpart of the American Medical Association, and Peru's Minister of Public Health declined the invitation to participate in the inaugural ceremonies of the event.

In 1988, 4000 participants from 41 countries attended the Second Congress, and the Minister of Public Health, the Dean of the Colegio Médico, and the Mayor of Lima all participated in the inauguration ceremony, along with a long list of university authorities. Published acts of the congress included important contributions on the medicinal flora of Peru 7273; and 74 for the Southern Andes. Subsequent publications of note include 5356 for the southern highlands and 6263 for the Peruvian Amazon region.

While he was director of the National Institute of Traditional Medicine, Dr. Cabieses was instrumental in coordinating a network of 16 ethnobotanical gardens in Peru, which included the cultivation of medicinal plants used by traditional herbalists. He also facilitated scientific research on traditional medicine building a large database of herbal plant uses. The subsequent administration discontinued these innovative programs and erased the database.

Moran, King, and Carlson 75 trace the emergence of biodiversity prospecting in the decade after the Convention on Biological Diversity (CBD) was signed.

For biodiversity-rich developing countries the most critical element in the CBD is sovereignty over bioresources, since the treaty recognizes right of nation states to regulate and charge outsiders for access to their biodiversity. The sovereignty component is meant to replace the "common heritage" paradigm, which provides unrestricted access to biological resources. Ideally this paradigm shift is supposed to balance the way in which all involved interest groups can gain from biodiversity use by recognizing the economic, sociocultural, and environmental values of bioresources and the cost of their preservation.

In the time since the CBD was initiated, few of the 178 signatory nations have introduced legislation requiring benefit sharing for outside commercial access to their national bioresources, although some suggestions for implementation of the CBD have been brought forward 7677. The U.S. and Peru are two non-activist countries. The U.S. never even signed the treaty while Peru's legislation does not enable mechanisms to conserve biodiversity. Recent environmental laws are just as toothless.

Despite the lukewarm response to the CBD, the global shift in awareness concerning tropical deforestation provided an opportunity for ethnobotanists to assert that everyone has an interest in preserving rainforests because they might contain compounds that could cure cancer, HIV-AIDS, and other diseases, as documented by 787980818283. Income derived from the marketing of traditional medicinal knowledge was seen as an instrument to alleviate poverty and to finance conservation efforts 78848586. However, within a few years, ethnobotany – initially seen as an instrument that could help to salvage declining traditional knowledge and biodiversity – had simply become an instrument of theft and "biopiracy" for its critics 78.

Moran, King, and Carlson [75, p. 508–509] discuss the irony in this situation, indicating the fact that the majority of the biotech industry is not involved in bioprospecting, since most companies favor the use of cheaper and faster synthetic technologies over exploring for natural products. Nonetheless, biotechnology spawns ethical, social, and legal debates at the margins of pharmaceutical bioprospecting, including the collaboration between big business and big science, the ethics of genetic engineering, and the patentability of life forms as well as ideas about genetics and racism, culture and ethnicity. However, it is significant to note that, since the inauguration of the CBD, no pharmaceutical bioprospecting product developed by using traditional knowledge has generated an economic profit. Also, only a small number of bioprospecting research expeditions begin by using ethnobotany as a discovery methodology, with the work soon evolving into economic botany as the laboratory focus shifts to the plant's chemistry, biological activity, and pharmacology/toxicology. During drug discovery, active chemical components are isolated, often modified, and patented. Patented information then becomes a commodity in itself.

Manek and Lettington in Cultural Survival 87 point out that by focusing on indigenous knowledge as it relates to the environment, the CBD managed to sidestep some of the more politically charged aspects of the intellectual property rights (IPR) issue. The greatest impact on concerns over indigenous and local-community rights can be traced to the mercurial rise of biotechnology on the international trade front and the 1995 version of the Word Trade Organization (WTO) Agreement on Trade Related Aspects of Intellectual Property Rights (TRIPS). These two factors have created a large potential market for indigenous and local knowledge and resources, while at the same time raising concerns about the risk that these resources will be misappropriated. Thus this knowledge is receiving increasing international attention in terms of its relationship to human rights as well as its relevance to modern science. The situation has created opposing pressures calling for the rights of local and indigenous peoples on the one hand and further exploitation of their knowledge on the other. 758788 indicate that the biggest problem with the orthodox intellectual property system is its focus on material aspects of knowledge at the expense of the cultural. They advocate recognition of alternative worldviews in the formulation of new indigenous knowledge rights that are localized, relevant, pertinent, and effective.

In their article in Cultural Survival Bannister and Barrett 89 contend that bioprospecting is a form of economic botany that can run contrary to the ethnobotanical objectives of protecting biological and cultural diversity. The economic focus of this activity highlights issues concerning indigenous rights, cultural knowledge, and traditional resources – areas in which current intellectual property protection regimes are inadequate and inappropriate. However, indigenous communities are increasingly forced to employ intellectual property rights to protect these resources. Protection issues ought to be addressed well before the point at which employing intellectual property mechanisms seems to be the only alternative. Significant control lies at the point of decision about publication and dissemination of knowledge to the wider community, which raises important questions about facilitating the appropriation of cultural knowledge. The authors [89, p. 10] advocate a more "precautionary" approach to ethnobotanical inquiry in assisting indigenous communities in protecting cultural heritage and intellectual property rights.

Probably the major concern in many traditional communities is that their spiritual legacies will be profaned by a secularized and consumer-driven outside world. Often, however, legitimate economic considerations also play a role in the defensive reactions of these societies to the well-intended but naïve desire of the academic world to place its findings in the public domain. Greaves 88 and others 89 warned that the downside in this approach is that a "colonialized archive" can become easily mined for clues in the search for new drugs without the inconvenience of fieldwork or benefit sharing.

Although acknowledging genuine concerns about neocolonialism and biopiracy, we would submit that each situation has to be considered on its own merits, especially with regard to its specific cultural context. A first step in the evaluation process should involve the important distinction between "indigenous peoples" and "local communities" [75, p. 518–519]. The latter for the most part are farmers who speak the national language, practice the majority religion, and identify with the nation-state, especially with regard to their socioeconomic aspirations, whereas the former tend to be tribal and/or ethnic minorities, who seek collective rights and self-determination for their biological and cultural resources. It is often the case that in local communities traditional knowledge and resources are undocumented and in danger of disappearing, as their members continue to adapt to modernization and globalization. In cases such as these successful ethnobotanical intervention requires a methodology that combines "salvage ethnography" with "rapid assessment". This is the methodology that we are applying in Peru, which provides the rationale for the present paper.

India provides a positive example of the proactive application of this rationale. By taking advantage of the "novelty" criterion in international patent law with regard to the documentation of Ayurvedic medicine and other traditional practices, millennial Sanskrit texts, as well as modern publications are included in a traditional knowledge database, which is subsequently provided to patent agencies. The expectation is that, by placing the knowledge about long-term cultural precedents for traditional uses in the public domain, this research will prove that contemporary patent applications derived from local medicinal knowledge lack originality, i.e., they are not "novel" enough to qualify as inventions warranting protection under international patent law, and are thus not patentable.

Plants were collected in the field, in markets, and at the homes of traditional healers (curanderos) visited in August-September 2001, July-August 2002, July-August 2003, June-August 2004, July-August 2005 and July-August 2006. The specimens are registered under the collection series "RBU/PL," "ISA," "GER," "JULS," "EHCHL," "VFCHL," "TRUBH," and "TRUVANERICA," depending on the year of fieldwork and collection location (see Additional file 1).

Vouchers of all specimens were deposited at the Herbario Truxilliensis (HUT, Universidad Nacional de Trujillo), and Herbario Antenor Orrego (HAO, Universidad Privada Antenor Orrego Trujillo). In order to recognize Peru's rights under the Convention on Biological Diversity, especially with regard to the conservation of genetic resources in the framework of a study treating medicinal plants, the identification of the plant material was conducted entirely in Peru. No plant material was exported in any form whatsoever.

The nomenclature of plant families, genera, and species follows the Catalogue of the Flowering Plants and Gymnosperms of Peru 20. The nomenclature was compared to the TROPICOS database. Species were identified using the available volumes of the Flora of Peru 90, as well as 919293, and reference material in the herbaria HUT and HAO. Complete species names with author names for all species are given in Additional File 1.

Ethnobotanical data were collected from plant sellers while purchasing plant materials in local markets (mostly Mercado Mayorista and Mercado Hermelindas in Trujillo and Mercado Moshoqueque and Mercado Modelo in Chiclayo), by accompanying local healers (curanderos) to the markets when they purchased plants for curing sessions and into the field when they were harvesting. In addition, plants were collected by the project members in the field, and – together with the material purchased in the markets – taken to the homes of curanderos to discuss the plants' healing properties, applications, harvesting methodology, and origins. At the homes of curanderos the authors also observed the preparation of remedies and participated in healing rituals. Plant uses were discussed in detail with informants, after seeking prior informed consent from each respondent. Following a semi-structured interview technique 9495, respondents were asked to provide detailed information about the vernacular plant name in Spanish or Quechua; plant properties (hot/cold); harvesting region; ailments for which a plant was used; best harvesting time and season; plant parts use, as well as mode of preparation and application; and specific instructions for the preparation of remedies, including the addition of other plant species. All interviews were carried out in Spanish, with at least one of the authors present. Both authors are fluent in Spanish, and no interpreter was needed to conduct the interviews.

Data on plant species, families, vernacular names, plant parts used, traditional uses and modalities of use were recorded and are given in Additional File 1.

Many of the species reported in this paper are widely known by curanderos, herb vendors, as well as the general population of the region, and are employed for a large number of medical conditions. One hundred fifty to two hundred plant species, including most of the introductions, are commonly sold in the local markets. Rare indigenous species are either collected by the healers themselves, or are ordered from special collectors or herb vendors. The same plants are frequently used by a variety of healers for the same purposes, with only slight variations in recipes. However, different healers might give preference to different species for the treatment of the same medical condition. All species found were well known to the healers and herb vendors involved in the study, even if they themselves did not use or carry the species in question. Many species were often easily recognized by their vernacular names by other members of the population. This indicates that these remedies have been in use for a long time by many people. The use of some species, most prominently "San Pedro" (Echinopsis pachanoi), "Maichil" (Thevetia peruviana) and "Ishpingo" (various species of Nectandra), can be traced back to the Moche culture (AC 100–800). Representations of these plants are frequently found on Moche ceramics, and the remains of some were found in a variety of burials of high-ranking individuals of the Moche elite, e.g. the tomb of the "Lord of Sipan."

The healers interviewed in Northern Peru belonged entirely to the Mestizo community. The naming of plant species follows three general patterns. Plant names already used by original indigenous populations are often maintained, although slightly modified. Plants similar to species already known, or with similar habitus, often receive the same name (transposition). In other cases, completely new names are created (neology) 96.

The vernacular names of the plants used in Northern Peru reflect the historical development of plant use in the region. Introduced species (e.g. Apium graveolens – Apio, Foeniculum vulgare – Hinojo), native species similar to species found in Spain (e.g. Adiantum concinnum – Culantrillo, Matricaria frigidum – Manzanilla), as well as species growing mostly in the coastal regions of the area (e.g. Alternanthera porrigens – Sanguinaria), are often addressed with names derived from Spanish roots. Plants from the mountain forests and especially the Andean highlands or the Amazon are often known by their Quechua names (e.g. Pellaea ternifolia – Cuti Cuti, Amaranthus caudatus – Quihuicha, Banisteriopsis caapi – Ayahuasca), and a few plant names can be traced back to Mochica roots (e.g. Nectandra spp. – Espingo). Van den Eynden observed similar patterns in Southern Ecuador 96, although her study focused only on edible species. Ninehundred thirty-eight vernacular names were recorded for 510 plant species. About one third if all names represented Quechua names or had Mochica roots, while 66.5% of all names were of Spanish origin or had at least Spanish components. In comparison, 41% of the verbacular names of edible plants in Southern Ecuador were found to be of Mestizo origin. More than half of the indigenous species carry only one vernacular name, with the remaining species carrying a variety of indigenous names, often derived from the same root. In comparison, almost 75% of the introductions are known by one name only. The slight differences in plant names indicate that the species have been used in the region for a long time, and that their names reflect small variations in the local dialects.

A total of 510 taxa belonging to 250 genera and 126 families are now on record. Of these, 504 could be identified, most of them to the species level. A detailed overview of all plants encountered, their scientific and vernacular names, and all uses, is given in Additional File 1.

Four hundred thirty-three species (85%) were Dicotyledons, 46 (9%) Monocotyledons, 21 (4%) Pteridophytes and 5 (1%) Gymnosperms. Three species of Giartina (Algae) and one species of the Lichen genus Siphula were used. Four hundred twenty-two species (83%) were indigenous to Northern Peru, while 87 species (17%) were introductions. Many of the introduced species were medicinal plants that were brought in for the treatment of European diseases during colonial times (Table 1).

The families best represented were Asteraceae with 69 species, Fabaceae (35), Lamiaceae (25), and Solanaceae (21). Euphorbiaceae had 12 species, and Poaceae and Apiaceae 11 species (Table 2).

Northern Peruvian curanderos prefer to use either the leaves (in 25% of all uses) or the whole plant (24%) for the preparation of their remedies. In 19% of the cases the stems of the plants were used, most commonly together with the leaves. Flowers (10%), seeds (7%), fruits and roots (4% each), bark (3%), fruit peel (2%), and latex and wood (1% each) were only used for a small number of preparations (Table 4).

Almost two-thirds (64%) of the remedies employed in Northern Peru are prepared using fresh plant material. Many of the introduced species are cultivated in fields and gardens, but the majority of the indigenous species are collected wild. This indicates that a widespread system of plant collectors is needed to supply the fresh plant material needed in traditional medicine. Most healers agreed, however, that in most cases dried material could be used if fresh plants were not available. In 36% of all cases the remedies were prepared using specifically dried plant material. The main explanation for this was however, that the plant material had to be transported from other regions, and thus fresh material was not available (Table 5).

Healers in Northern Peru often employ very sophisticated mixtures of a variety of plants in their treatments. The use of single species for treatments was rare. Most commonly, plant material was boiled in water, or in some cases in sugarcane alcohol (aguardiente) to extract the active compounds. In some cases, plant material was macerated in cane alcohol or wine for longer periods of time, before use.

The curanderos all had strikingly exact recipes for treatment, with very specific quantities of plant material used to prepare remedies. These quantities did not differ greatly from one healer to another. Simultaneously, the amount of a specific remedy that was given to a patient was very similar among the different curanderos.

The most frequent way to administer remedies was to prepare a decoction and ingest it orally (52% of all uses), followed by application as a poultice (38%, plant crushed or boiled and applied). Seven percent of all plant uses entailed the preparation of a seguro, a bottle or small flask filled with plant material along with various perfumes. This amulet has to be carried by the patient at all times, or it is placed in the house and used for periodic blessings. Seguros contained anything from a handful to more than three-dozen different ingredients. In two percent of the plant uses the material was employed to fabricate charms, and in one percent of all applications the plant material was burned as incense, with the smoke inhaled for treatment (Table 6).

A variety of species normally used as food also had some medicinal applications, mostly as nutritional supplements to treat mineral and vitamin deficiencies and malnutrition, and were prepared and served as side-dishes or as ingredients of normal meals. Old Andean crops like Quinoa (Chenopodium quinoa), Kichwa (Amaranthus caudatus), Tarhui (Lupinus mutabilis) and Maca (Lepidium meyenii) – now globally used as a supplement – featured most prominently. Coastal species like Algarrobo (Prosopis pallida) were also used. Altogether 12 species (2.3%) were used in this way.

Palm staffs (Bactris spp.) are still used as power objects on Northern Peruvian mesas.

If the botanical documentation of Peruvian medicinal plants has been neglected for a long time, investigations on the phytochemical composition of useful plants is lagging even further behind. Most studies on the phytochemistry of Peruvian plants concentrate on a few "fashionable" species that have been marketed heavily on a global scale, especially Maca (Lepidium meyenii), Sangre de Drago (Croton lechleri), and Cat's claw/Uña de Gato (Uncaria tomentosa and Uncaria guianensis). The number of other Peruvian plants for which at least limited phytochemical studies exist is still minuscule, and most efforts are fueled by the fads and fashions of the international herbal supplement market. Studies involving multiple species were initiated as late as 1990s 9798, and are still the exception to the rule.