Use and knowledge of fuelwood in three rural caatinga (dryland) communities in NE Brazil

The caatinga (semi-arid vegetation) is a Brazilian biome with a significant but poorly studied biodiversity closely associated with a diverse cultural heritage. The present work focused on analyzing published information available concerning medicinal plants used by traditional communities. We sought to contribute to future phytochemical and pharmacological investigations by documenting the therapeutic uses of native caatinga plants within the aims of modern ethnopharmacological research. Twenty-one published works cited a total of 389 plant species used by indigenous and rural communities in northeastern Brazil for medicinal purposes. The relative importance index (RI) of each species in these inventories was calculated, and information concerning the plant's local status (spontaneous or cultivated), distribution, and habit was recorded. Of the 275 spontaneous (non-cultivated) species cited, 15.3% were endemic to the caatinga. A statistical relationship was verified between the relative importance of the species and their endemic status (p<0.05). Herbaceous plants were more numerous (169) than trees (90) or shrubs and sub-shrubs (130) at a statistically significant level (p<0.05). A survey of published information on the phytochemical and pharmacological status of the plants demonstrating the highest RI supported the veracity of their attributed folk uses.

Background The Caatinga (dry land vegetation) is one of the most characteristic vegetation types in northeastern Brazil. It occupies a large percentage of the semi-arid region there, and generally supports two major types of economic activity: seasonal agriculture and the harvesting of plant products. However, very little information is available concerning the interaction of people with the plants of the Caatinga. Methods A study was undertaken with the participation of 31 adults from a rural community in the state of Pernambuco, Brazil, in order to analyze the patterns of use of medicinal plant resources, and to test a number of hypotheses concerning their use and local knowledge about them. The sources of medicinal plants used by the local community, the differences in oral information concerning the use of plants with their effective uses, and the role of exotic plants in local folk medicine practices were examined. Results Forty-eight plant species were cited as having medicinal uses, of which 56.25% are native to the Caatinga region. The patterns of harvesting and the importance of these trees and shrubs as medicinal plants seem to be compatible with a hypothesis based on the seasonal availability of plant resources. There is no direct correlation between known medicinal plants and those used by the local population, which agrees with observations made in different tropical regions. However, this observation was not interpreted in terms of the idea of "erosion" of knowledge (commonly used to explain this lack of correlation), but rather to propose two new concepts: "mass knowledge" and "stock knowledge". Conclusion Native plants are a very significant component of locally used medicinal plants, although exotic plants are important for treating specific health problems – which leads the proposal of a hypothesis of diversification.

Medicinal plant use has persisted as a long standing tradition in the Mapuche communities of Southern Argentina and Chile. An ethnobotanical survey was conducted in the rural Curruhuinca community located near the mountain city of San Martin de los Andes, Argentina. Semi-structured interviews were carried out on 22 families in order to examine the present use of medicinal plants and their reputed therapeutic effects. Ecological variables, such as distance to the gathering site and biogeographical origin were also analyzed. Our results showed that the Curruhuinca dwellers cited 89 plant species for medicinal purposes, both of native and exotic origin. They know about 47 native plants, of which they use 40, and they know of 42 exotic medicinal plants of which they use 34. A differential pattern was observed given that only native species, relevant for the traditional Mapuche medicine, were collected at more distant gathering sites. The interviewees mentioned 268 plant usages. Those most frequently reported had therapeutic value for treating digestive ailments (33%), as analgesic/anti-inflammatory (25%) and antitusive (13%). Native species were mainly cited as analgesics, and for gynecological, urinary and "cultural syndrome" effects, whereas exotic species were mainly cited for digestive ailments. The total number of medicinal plants known and used by the interviewees was positively correlated with people's age, indicating that this ancient knowledge tends to disappear in the younger generations.