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    ABSTRACT: The variety of pathways for the introduction of a species into the medical collection of traditional communities has led many researchers to question the processes of selection and the use of these resources. A better comprehension of these processes will allow us to understand the cultural dynamics that are related to traditional medical practices, as well as to provide us with new ways in which to facilitate the exploration of natural products. This study aims to test the predictive power of the plant apparency hypothesis as it relates to medicinal plant selection by the rural communities of the Caatinga and the Atlantic Forest in northeast Brazil. Initially, a survey of the medicinal plants used by these communities was conducted using semistructured interviews. Subsequently, data on the life strategies and the habits of each species were collected. More detailed data on the specific plant parts indicated in interviews were also collected. A phytochemical screening for seven classes of chemical compounds was carried out to test the predictions of the plant apparency hypothesis. The medicinal plants from the Caatinga (especially those that are considered to be trees in habit) have a strong ability to accumulate quantitative compounds, and these species are most likely to be plants with significant biological activity related to these compounds; the medicinal plants from the Atlantic Forest, on the other hand, tend to have a high occurrence of qualitative compounds, especially in herbaceous life forms. It was concluded that the plant apparency hypothesis does not adequately explain the selection of medicinal plants in the two environments studied. Our findings highlight some important implications for bioprospecting that need to be further tested experimentally, and through systematic studies, in different regions.
    Pharmaceutical Biology 08/2011; 49(8):864-73. DOI:10.3109/13880209.2010.551777 · 1.34 Impact Factor
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    ABSTRACT: In the Northwest of Tunisia, mining works have occurred in an area of vital water reserves and resources (Oued Mellègue and Oued Mejerda), which represent nearly 81% of total potential of water in the region. Demographic growth, insufficient drinkable water, agriculture and industrial plants are factors responsible for the strong demand of this resource. Water supply is done by an interconnected battery of dams built on the major watercourses, the first of which, the Mellègue dam, was erected in the 1960s. Nowadays, most of the mines are closed for almost two decades although one is still active: (Jerissa for Fe). It is important to emphasise the fact that there are millions of cubic metres of abandoned tailings, mainly from Pb–Zn–Ba mines, which are not surveyed, representing a serious threat to the environment.Exposed superficial mineralised tailings, weathering of sulphide minerals, and the presence of siderite and phosphorites as well, accelerate the oxidation and generate leaching solutions rich in toxic base-metals (Cd, Pb, Hg, Zn, U, among others, are the most important). Trace element analyses performed on tailings and stream-sediments samples and the use of “Principal Component Analysis” statistical method, helped to understand the processes of toxic metals circulation in the natural environment. It showed that the major and trace metals fate and transfer from contamination sources into the river systems are based on three main factors: i) a mineralogical component which is representative of regional rocks (shales, siliciclastics, limestones, and dolostones), ii) a residual assemblage concerning the ore mineral micro phases (phosphorites and common and complex sulphides of Pb and Zn) and iii) hydrated iron oxyhydroxide components representing the complex geochemical processes taking place, which are extremely active in scavenging toxic metals in either weathered tailing profiles or continuously reworked stream depositional systems. In addition, the superficial lime fraction and the Triassic-derived gypsum and halite could play a significant role in precipitating and thus fixing heavy metals in the proximity of various sources of contamination defined by tailing areas which are constantly being leached.
    Journal of Geochemical Exploration 03/2009; 102(1):27-36. DOI:10.1016/j.gexplo.2008.11.016 · 2.43 Impact Factor