Life strategy and chemical composition as predictors of the selection of medicinal plants from the caatinga (Northeast Brazil)

An ethnobotanical study was undertaken in conjunction with a phytochemical approach to the medicinal flora of the caatinga, popularly used in communities of the Xingó region (Northeast Brazil); the focus was on applying the apparency theory to explain the choice and use of these plants. Initially, an ethnobotanical study was carried out to survey the medicinal plants used in the region in which 339 people were interviewed using standardized questionnaires. To eliminate the effect of cultural interference, exotic plants cultivated intentionally were not considered, which resulted in a total of 41 species. In the field, data was obtained on the types of life strategies and habit for each species and plant parts indicated for medicinal use were collected. A phytochemical study was undertaken with five classes of chemical compounds for the species collected. Significant differences were found in the number of positive occurrences for each of the compound classes in relation to life strategy and habit. Strategist-K plants had a greater number of occurrences than strategist-r plants. In general, trees were more diversified than herbs and bushes in relation to the presence of compound classes. The scores (local relative importance)obtained for each plant are independent from compound classes found, habit, life strategy, and plant part used. Nevertheless, strategist-K species obtained the highest averages.