Actualized inventory of medicinal plants used in traditional medicine in Oaxaca, Mexico

Abstract

Background: Oaxaca is one of the most diverse states in Mexico from biological and cultural points of view. Different ethnic groups living there maintain deep and ancestral traditional knowledge of medicinal plants as well as traditional practices and beliefs about diseases/illnesses and cures. Previous ethnobotanical research in this state has helped document this knowledge, but with the addition of more studies, more records appear. We updated the inventory of medicinal knowledge between the different ethnic groups that inhabit the Oaxacan territory.

Methods: A database was constructed from two sources: (1) original data from a 3-year project in 84 municipalities of Oaxaca inhabited by eight ethnic groups and (2) different electronic databases.

Results: Records of 1032 medicinal plants were obtained; 164 families were registered, with Asteraceae, Fabaceae, and Rubiaceae being the most commonly used. A total of 770 species were reported in 14 vegetation types; the most important species came from temperate forests. Only 144 species corresponded to introduced species, and 272 were listed in a risk category. Illnesses of the digestive and genitourinary systems as well as culture-bound syndromes were treated with high numbers of medicinal plants. The Mestizo, Mixe, Mixtec, and Zapotec ethnic groups exhibited the greatest number of recorded medicinal plants. The 17 species that were used among almost all ethnic groups in Oaxaca were also used to cure the highest number of diseases.

Discussion: Inventories of medicinal plants confirm the persistence of traditional knowledge and reflect the need to recognize and respect this cosmovision. Many species are gathered in wild environments. The most important illnesses or diseases recorded in the present inventory are also mentioned in different studies, suggesting that they are common health problems in the rural communities of Mexico.

Conclusions: Medicinal plants are essential for ethnic groups in Oaxaca. It is necessary to recognize and understand the complex ancestral processes involved in the human-nature interaction and the role of these processes in the conservation of biodiversity and in the survivorship of ethnic groups that have persisted for centuries. Finally, this study serves as a wake-up call to respect those worldviews.

Keywords: Biodiversity; Cosmovision; Diseases; Ethnic groups; Gathering; Medicinal plants; Oaxaca; Risk category.

Fig. 1

Ten most representative botanical families with medicinal plant species used in Oaxaca, Mexico

Fig. 2

Number of medicinal plants recorded in each vegetation type in Oaxaca, Mexico. (Acronyms: OF oak forest, PF pine forest, MCF montane cloud forest, TDF tropical deciduous forest, NA not available, TEF tropical evergreen forest, RMV river-margin vegetation, TSF tropical semi-evergreen forest, SHR shrubland, GRS grassland, FF fir forest, TSDF tropical semi-deciduous forest, ODC oak-dominated chaparral, CT cardonal and tetechera, TTF tropical thorn forest)

Fig. 3

Number of species included in one of the risk categories by SEMARNAT [52] AND IUCN [53]

Fig. 4

Number of medicinal plant species used for different illness system, according to Pérez-Nicolás et al. [32] and WHO classification [51]

Fig. 5

Number of medicinal plant species that attended one, two, three or more illness systems. The number of species with no records is indicated (NA)

Fig. 6

Number of medicinal plants recorded for each ethnic group in Oaxaca, Mexico (black bars=total number of species recorded; gray bars=species added by JF102 project)

Fig. 7

A hierarchical classification analysis (HCA) using Ward’s method on the Euclidean distance matrix was followed. Groupings obtained from the HCA were graphically evaluated with principal component analysis (PCA) on a correlation matrix (PAST 4.01).The first two axes of the PCA explained approximately 97% of the variance.