A comparison of knowledge about medicinal plants for three rural communities in the semi-arid region of northeast of Brazil

Aim: The aim of this research was to understand the importance of native and exotic plants in local medical systems in the Caatinga of the Brazilian northeast, and the influence of socio-economic factors on the acquisition of knowledge about these resources. Methods: A total of 55 people were interviewed in three rural communities using free list and semi-structured interviewes. Results: A total of 108 ethnospecies were reported, 99 of which were identified; 43 of these were preferred by informants. Most of the plants cited were exotic (51) but the difference in diversity among these plants and native plants (48) was not considered significant (p > 0.05). The exotic plants were predominantly herbaceous and used to cure diseases that native plants did not seem to treat. There were no differences between men's and women's knowledge of the plants (p > 0.05). However, for some communities, factors such as age and income were correlated with the number of citations and indications for plants, which suggested that older people and those with higher income levels had more knowledge about these properties. Conclusion: The data presented in this study showed the importance of exotic species in the region studied and demonstrated that plant knowledge can be perceived as a way to diversify options for medical treatment in the area. (C) 2009 Elsevier Ireland Ltd. All rights reserved.