Plants used as medicinal in Güémez, Tamaulipas, north-eastern Mexico

The use of medicinal plants in Mexico has a diverse and deeply-rooted tradition concerning. Plants play an important role in traditional medicine among the inhabitants of Güémez, Tamaulipas in northeastern Mexico. With the aim of obtaining quantitative information on the plants and their uses as medicinal sources, semi-structured interviews with 113 local residents were taken. In addition, Informant Consensus Factor (ICF) and Use Value (UV) were calculated. A total of 85 species of medicinal plants belonging to 44 families were identified. The most common families were Asteraceae, Lamiaceae and Euphorbiaceae. The most used part of the plant was the leaf and the most frequent preparation method was boiling, preparing as an infusion. A total of 50 medicinal uses were registered. Fever had highest ICF (0.93), whereas, according to UV, the most important plants were Artemisia ludoviciana Nutt., Mentha spicata L., Matricaria recutita L. and Achillea millefolium L. The information generated strengthens traditional knowledge, bringing new species and uses to the country ́s records for future phytochemical studies that could lead to new medicines.


Introduction
About 80% of the world's population relies on traditional medicine to satisfy primary health care needs (Bermúdez et al., 2005;Ayyanar and Ignacimuthu, 2011;Panyaphu et al., 2011). The World Health Organization has registered approximately 21,000 plant species for medicinal uses around the world (Malla et al., 2015). Medicinal plants are an important source of current drugs. About 25% of the world's prescription drugs come from plants (Bulut and Tuzlaci, 2013).

AcademicPres
Notulae Botanicae Horti Cluj-Napoca Agrobotanici 1131 Mexico has a diverse and deeply-rooted tradition concerning the use of medicinal plants (Estrada-Castillón et al., 2018). In Mexico, there are more than 23,400 vascular plants and 5,000 species are used for medicinal purposes and the most important families are Asteraceae, Lamiaceae, Fabaceae, and Euphorbiaceae (Casas et al., 2001;Camou-Guerrero et al., 2008;Alonso-Castro et al., 2012). Also is ranked sixth in the world regarding greatest cultural diversity (Mercado, 2013), as it has 62 ethnic groups (Juárez-Rosete et al., 2013). Most ethnic groups use medicinal plants because of their efficiency, tradition and low costs (Kayani et al., 2015;Tribess et al., 2015). In particular, rural areas contribute with most knowledge about medicinal plants (Kayani et al., 2015). These plants help communities to survive in remote areas (Gómez, 2012).
Nowadays, it's recognized that in Mexico and many countries around the world the transmission of knowledge regarding the use of medicinal plants from old to new generations is declining are experiencing loss of useful plants due (Quesada, 2008;Calvo et al., 2011;Hassan-Abdallah et al., 2013) as well as losing entire villages and local populations due to lack of work, education and medical care (Panyaphu et al., 2011). This fact is also a reality in rural communities because of globalization and the use of allopathic medicine (Esquivel-García et al., 2018). Therefore, it is important to rescue this knowledge to prevent the loss of ethnomedical traditions, which is a scientific and cultural heritage important for future generations.
The municipality of Güémez, located in the northeast of Mexico, covers 1.5% of the Tamaulipas state. Its economy is based on agriculture (citrus, safflower, bean, maize, henequen and sorghum), cattle raising and forestry production also take place on smaller scale. However, there are no local inhabitants selling medicinal plants. The local people live in houses of 'adobe' (building material made from soil and often organic material), wood and concrete. Health services are scarce with little medicine and few doctors. Some villages do not have drainage, clean water, electricity, so migration is commonplace due to lack of security, education and employment.
The objective of this study is to know the most commonly used medicinal plants and their uses by the inhabitants of the municipality of Güémez with the purpose to revaluing and saving this traditional knowledge in this region of Mexico.

Study area
The municipality of Güémez is located within the Sierra Madre Oriental and is part of the centralwestern region of State of Tamaulipas ( Figure 1) (24°06'-23°41'N and 99°30-98°45'W), its altitude is from 200 to 2,800 m. It covers 1,204.55 km 2 , has 43 localities with a population of 15,659 inhabitants, of which 80% live in urban areas and 20% in small villages called 'ejidos'. The climate of the region is temperate to sub-humid, in mountainous areas and semi-dry to very warm in the lowlands. The mean annual temperature ranges from 12 to 26 °C and the annual rainfall is 600 to 1,100 mm (INEGI, 2009).

Fieldwork
Wild and cultivated medicinal species in the study area were collected. Plant samples obtained were pressed and dried according to the method described by Sánchez-González and González (2007). Specimens were identified by the authors through the Manual of the Vascular Plants of Texas (Correll and Johnston, 1970), scientific names were consulted in The Plant List (http://www.theplantlist.org/). The complete collection of specimens was included in the CFNL herbarium (acronym according to Thiers, 2011). We include the common name in Spanish for all plants species registered during interviews.
The ICF adapted by Heinrich et al. (1998), is calculated according to following formula: ICF = (Nur-Nt) / (Nur -1) where Nur refers to number of citations of uses given in each category and Nt to number of species used. This method is used to test the homogeneity of information. The ICF offers a range of 0-1, where high values (about 1) are obtained, when there is a well-defined selection criterion in the community and/or if information is exchanged between informants, and the values are low (near zero) if plants are chosen at random or if there is no exchange of information about their use among informants.
The use value (Trotter and Logan, 1986), demonstrates the relative importance of locally known species and is calculated according to the following formula: UV = U / N, where U refers to number of citations per species and N to number of informants.

Richness of medicinal plants
According to the results of specimen identification, 85 species with medicinal uses, belonging to 41 families were reported by interviewees. Among them, 45 species are cultivated and 40 species are wild. The most common families of medicinal plants are Asteraceae (17.64%), Lamiaceae (11.76%), Euphorbiaceae (7.05%) and Rutaceae (4.70%). During the study, 126 samples were collected in the study area. Plants used for medicinal purposes in Güémez are presented in Appendix 1 in alphabetical order according to family and scientific name. The biological forms of the medicinal species mentioned by the interviewees were herbaceous (47 species), shrubs (21 species) and trees (17 species).
The most frequently used plant parts for the preparation of medicines were leaves (42 plants

Informant consensus factor (ICF)
There were 13 main categories of ailments based on ICF data. The ICF interval was 0.1 to 0.93. The results showed that the highest ICF was reported for the fever category with a value of 0.93, followed by ophthalmological problems (mainly eye infections) (0.75), intestinal parasites (mainly worms) (0.75), respiratory ailments (mainly colds) (0.72) and endocrine system (mainly diabetes) (0.66), gastrointestinal system (0.59) and bumps and wounds (0.59) ( Table 1).

Method of preparation of the traditional medicines
The medicinal plants used by the local inhabitants are prepared and administered in different ways. Various methods of preparation and application are presented. According to ailment, preparation differs such as being boiled (62 plants), taken raw (17 plants), fermented in water (6 plants), cooked (3 plants), fermented in alcohol (2 plants), and fried (1 plant) (Appendix 1). Boiled and crude are the most commonly used methods for preparation of remedies. As a result of the records of the interviews, 50 species of plants are prepared for consumption, 15 plants are prepared for external use, while 20 species are used to alleviate both internal and external ailments.

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The main routes of administration of the plants are oral (76%), followed by intestinal washes (24%) and poultices (4%). We do not include the exact proportions used for each medicinal plant, because there is a contradiction with respect to the exact dosage. The dose is usually measured by cups of infusion.
Most remedies are based on the use of a plant. However, Table 2 shows eleven combinations of medicinal plants reported by informants. Most are composed of six species, of which Mentha spicata is the plant most used in several combinations, followed by Psidium guajava, Ocimum basilicum, Ruta graveolens, Matricaria recutita and Poliomintha longiflora. The combination of the species Crataegus tracyi and Arctostaphylos pungens is the most recorded one found during the interviews. The main ailments treated with these mixtures are gastrointestinal diseases.  (Ghorbani et al., 2011;Bulut and Tuzlaci, 2013;Leto et al., 2013;Nawash et al., 2013;Bolson et al., 2015), probably due to the high diversity of its phytochemical constituents. Some studies have reported that this family has a wide range of biologically active compounds and has high species richness worldwide Thomas et al., 2009). Following the IUCN Red List of Threatened Species, the only species under protection status is Dalea scandens (Mill.) R.T. Clausen assessed as being of Least Concern (Groom, 2012).
The possible reasons that herbaceous plants have the highest frequency of use is because bioactive compounds can be easily extracted (Lulekal et al., 2013;Kayani et al., 2015) and their high availability (planted in gardens, wild habitat and roadsides) (Tsobou et al., 2013). Similar conclusions are drawn from other studies in other parts of the world (Ghorbani et al., 2011;Sivasankari et al., 2014;Yaseen et al., 2015).
The medicinal species best known by the population in the study area were those that were used for uncomplicated ailments, similar findings are reported by Pérez-Nicolás et al. (2017) for the state of Oaxaca in southeaster Mexico.
The most frequently used plant parts for the preparation of medicines were leaves. Several ethnomedicinal studies in Mexico, Bangladesh, China, Colombia and India have reported that leaves are the most used parts of plants (Singh and Singh, 2009;Teklehaymanot, 2009;Packer et al., 2012;Sivasankari et al., 2014;Pérez-Nicolás et al., 2017;Estrada-Castillón et al., 2018). This is because they are the most abundant part of a plant and they are easier to collect (Giday et al., 2003). It may also be due to their greater effectiveness, since leaves have increased amounts of secondary metabolites like alkaloids, tannins and inulins, which are active components of many medicines (Yemele et al., 2015). In addition, the use of leaves favors the conservation of plants, since the collection of roots can kill the plant and endanger the species (Telefo et al., 2012;Kadir et al., 2013).
In the study area the most frequently used medicinal species are Artemisia ludoviciana, Mentha spicata, Matricaria recutita and Ruta graveolens, in the same way such plants are used by the inhabitants of Santiago Camotlán, Oaxaca (Pérez-Nicolás et al., 2017).

Disease categories
Ethnobotanical studies reveal that stomach pain is the most frequent ailment treated by medicinal plants (Polat and Satil, 2012;Kayani et al., 2015;Tribess et al., 2015;Estrada-Castillón et al., 2018). Globally, gastrointestinal diseases account for 2.2 million deaths each year and are caused by viruses, bacteria or parasites (Monigatti et al., 2013). The second most notable illness was related to the kidneys, which may be due to low intake of water during the cold season and the hard-agricultural work (Kayani et al., 2015).
In the study area medicinal plants are also used for magical purposes, like to remove bad luck. This is a common practice in the Mexican tradition (Frei et al., 1998;Andrade-Cetto, 2009). Since ancient times in Mexico, people have believed that diseases were caused by evil spirits, witchcraft and magic (Gallardo-Arias, 2004). Local healers prescribe medicinal plants, through a ritual of prayers while rubbing medicinal plants on the body of sick person. Most informants mentioned that such traditional knowledge was transmitted by their parents and grandparents over the years.

Use Value (UV) and Informant Consensus Factor (ICF)
Most of the plant's species registered in this study are native to Europe and Asia and their use may have been popularized in Mexico because of their efficiency, adaptation and fast growth (Juárez-Rosete et al., 2013).
The high values of ICF could indicate that these diseases are common in the studied population, where there is a need to cure these diseases, and, thus, there is knowledge among the local population about the uses of medicinal plants (Nawash et al., 2013).

Method of preparation of the traditional medicines
Oral is the most routes of administration of plants used by the inhabitants of this study area because of their ease, similar findings have been reported in countries such as Pakistan (Kadir et al., 2012(Kadir et al., , 2013 and India (Ayyanar and Ignacimuthu, 2011).
Most remedies are based on the use of a plant and other is combinations of medicinal plants reported by informants. This can be attributed to the fact that any one plant can contain several compounds that perform different functions in the body (Focho et al., 2009). The plants are combined because people believe that the blend could improve the synergistic effect of the pharmacological effects of plants (Igoli et al., 2005;Giday et al., 2010).

Conclusions
This study reveals that for the inhabitants of the municipality of Güémez, the use of traditional medicine is frequent, and most local people still rely on plant-based remedies for common health problems. Thus, we emphasize the need to develop actions to avoid the loss of traditional knowledge of medicinal plants, not only to preserve this cultural heritage but also to record information on useful species that could be used to develop new medicines and provide other benefits, while contributing to protecting local biodiversity.