Thiago Antônio de Sousa Araújo

A new approach to study medicinal plants with tannins and flavonoids contents from the local knowledge

AIM OF THE STUDY The present work tested the power of different methodological strategies for identifying plants that could be interesting in terms of their phenolic compounds (especially flavonoids and tannins) by comparing a new index in which priority-determining criteria are based on the free-listing technique as well as on two randomized methods for choosing plants within an ethnodirected based approach. MATERIALS AND METHODS The present study was undertaken in the rural area of the municipality of Altinho located in the central region of Pernambuco State, northeastern Brazil. The ethnobotanical survey was divided into three different stages. The first stage was a general survey of 101 individuals on the use and knowledge of medicinal plants within the community. During the second stage local specialists were selected on the basis of the quality and quantity of information they offered during the initial phase of the investigation. The third stage consisted of returning to the specialists a final time in order to apply the free-listing technique. We also assumed that a plant could demonstrate anti-inflammatory and healing effects even without the presence of the compounds of interest of this study. RESULTS There is a strong association between tannin content and the effects popularly attributed to wound-healing and anti-inflammatory plants. No relationships were observed between plants used by the community to treat inflammation or healing with their flavonoid contents. CONCLUSION Thus, identifying Caatinga medicinal plants known with anti-inflammatory activity and healing capacities is a good criterion for identifying species with high levels of tannins, although these same criteria are not useful for identifying plants with high flavonoid contents.

How ethnobotany can aid biodiversity conservation: reflections on investigations in the semi-arid region of NE Brazil.

Ethnobotany is a relatively new discipline but its social and scientific roles are becoming more consistently defined and its importance as a tool for complimenting management and conservation strategies at local and regional levels is now well recognized by the scientific community throughout the world. In the present work we have collected information from four years of ethnobotanical study in an area of caatinga vegetation in the semi-arid region of northeastern Brazil with the goal of defining a model for conservation and management actions in the region. Drawing on ethnobotanical and ecological information obtained through traditional techniques of ethnobotanical and vegetation surveys, we discuss the uses of 166 native and exotic plant species and suggest specific actions and specific groups of species for conservation and sustainable use programs. We also discuss the limitations of our approach and indicate what information must still be collected in order to construct robust and workable plans of action.

The Inclusion and Selection of Medicinal Plants in Traditional Pharmacopoeias—Evidence in Support of the Diversification Hypothesis

The Inclusion and Selection of Medicinal Plants in Traditional Pharmacopoeias—Evidence in Support of the Diversification Hypothesis. An ethnobotanical study with phytochemical analyses was undertaken to examine the medicinal plants used by residents of a small rural community in northeastern Brazil. The present work tested two ideas that attempt to explain the inclusion and selection of medicinal plants in a given culture: the diversification hypothesis and the concept of versatility. The study involved 101 people and used semistructured interviews. A total of 61 plants were selected, including 25 exotic and 36 native species. Plants were classified according to their habit and analyzed for their phytochemical components. In addition, the relative importance (RI) of these plants was calculated, and a chemical diversity index (CDI) was created and applied to each of the species. Exotic and native plants were found to have significantly different occurrences of certain classes of compounds; this result supports the diversification hypothesis. It was therefore concluded that exotic plants are included in traditional pharmacopoeias to fill therapeutic vacancies that native plants cannot satisfy.

Antiproliferative Activity, Antioxidant Capacity and Tannin Content in Plants of Semi-Arid Northeastern Brazil

The objective of this study was to evaluate antiproliferative activity, antioxidant capacity and tannin content in plants from semi-arid northeastern Brazil (Caatinga). For this study, we selected 14 species and we assayed the methanol extracts for antiproliferative activity against the HEp-2 (laryngeal cancer) and NCI-H292 (lung cancer) cell lines using the (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazole) (MTT) method. In addition, the antioxidant activity was evaluated with the DPPH (2,2-diphenyl-2-picrylhydrazyl) assay, and the tannin content was determined by the radial diffusion method. Plants with better antioxidant activity (expressed in a dose able to decrease the initial DPPH concentration by 50%, or IC50) and with higher levels of tannins were: Poincianella pyramidalis (42.95 ± 1.77 µg/mL IC50 and 8.17 ± 0.64 tannin content), Jatropha mollissima (54.09 ± 4.36µg/mL IC50 and 2.35 ± 0.08 tannin content) and Anadenanthera colubrina (73.24 ± 1.47 µg/mL IC50 and 4.41 ± 0.47 tannin content). Plants with enhanced antiproliferative activity (% living cells) were Annona muricata (24.94 ± 0.74 in NCI-H292), Lantana camara (25.8 ± 0.19 in NCI-H292), Handroanthus impetiginosus (41.8 ± 0.47 in NCI-H292) and Mentzelia aspera (45.61 ± 1.94 in HEp-2). For species with better antioxidant and antiproliferative activities, we suggest future in vitro and in vivo comparative studies with other pharmacological models, and to start a process of purification and identification of the possible molecule(s) responsible for the observed pharmacological activity. We believe that the flora of Brazilian semi-arid areas can be a valuable source of plants rich in tannins, cytotoxic compounds and antioxidant agents.

Levels of Tannins and Flavonoids in Medicinal Plants: Evaluating Bioprospecting Strategies

There are several species of plants used by traditional communities in the Brazilian semiarid. An approach used in the search for natural substances that possess therapeutic value is ethnobotany or ethnopharmacology. Active substances that have phenolic groups in their structure have great pharmacological potential. To establish a quantitative relationship between the species popularly considered to be antimicrobial, antidiabetic, and antidiarrheal, the contents of tannins and flavonoids were determined. The plant selection was based on an ethnobotanical survey conducted in a community located in the municipality of Altinho, northeastern Brazil. For determination of tannin content was utilized the technique of radial diffusion, and for flavonoids, an assay based on the complexation of aluminum chloride. The group of plants with antimicrobial indications showed a higher content of tannins compared to the control groups. The results evidence suggests a possible relationship between these compounds and the observed activity.

Can the Apparency Hypothesis explain the selection of medicinal plants in an area of caatinga vegetation? A chemical perspective

This scientific note examines the ability of the apparency hypothesis to explain the selection of medicinal plants by members of a rural community located in the Caatinga dryland region of Pernambuco state. A total of 61 plants considered to be medicinal were examined phytochemically to test the premises of this hypothesis. It was concluded that apparency does not completely explain our findings.

Intracultural Variation in the Knowledge of Medicinal Plants in an Urban-Rural Community in the Atlantic Forest from Northeastern Brazil

This study assessed the intracultural knowledge of the use of medicinal plants in an urban-rural community in an Atlantic forest fragment in northeastern Brazil. We examined the importance of native and exotic species and the effects of gender and age on that knowledge. We also compared data obtained from different groups of informants (local experts and general community). We conducted 194 interviews between June 2007 and January 2008, using the freelist technique and semistructured forms to collect ethnobotanical data. Information obtained from the community was compared with that from six local experts who participated in a survey in 2003. From a total of 209 ethnospecies, exotic and herbaceous plants presented higher richness. With respect to the number of citations, women and older informants were shown to know a higher number of medicinal plants. Comparing knowledge of local experts with that of the general community, we noted that experts know a similar wealth of plant families and therapeutic indications, but the community knows a greater species richness. These results indicate that local experts may provide useful information for studies that search for a quick diagnosis of the knowledge of a given community.

Habitat influence on antioxidant activity and tannin concentrations of Spondias tuberosa

Context: Different habitat conditions can be responsible for the production of secondary metabolites and for the antioxidant properties of plant products. Objective: Thus, the aim of this study was to evaluate whether the antioxidant activity and tannin concentrations in the stem bark of Spondias tuberosa Arruda (Anacardiaceae) varied with collection site. Material and methods: The bark was collected from 25 individual trees, distributed in five different landscape units, as follows: agroforestry gardens, areas of pastures, maize cultivation areas, mountain areas and mountain bases, with the former 3 being considered as anthropogenic habitats, and the latter 2 considered as habitats with native coverage. The study was conducted in the rural area of the city of Altinho, Pernambuco State (Northeast Brazil). The DPPH (1,1-diphenyl-2-picrylhydrazyl) method was used to measure the antioxidant activity and tannin concentrations were evaluated by using the radial diffusion method. Results: The results demonstrated that there were no significant differences among the tannin concentrations of the individuals from the native (6.27% ± 1.75) or anthropogenic areas (4.63% ± 2.55), (H = 2.24; p > 0.05). In contrast, there were significant differences (H = 5.1723; p < 0.05) among the CE50 means of the antioxidant activities of the individuals from the native (32.10 µg/ml ± 5.27) and anthropogenic areas (27.07 µg/ml ± 2.29). However, correlations between the tannin concentrations and antioxidant activity of the extracts were not observed in the native (r = 0.39; p > 0.05) or in the anthropogenic areas (r = 0.38; p > 0.05). Discussion and conclusion: Because the variation of the antioxidant capacity of S. tuberosa bark was not accompanied by a variation in the tannin concentration, this property may be related to the presence of other metabolite(s).Context: Different habitat conditions can be responsible for the production of secondary metabolites and for the antioxidant properties of plant products.Objective: Thus, the aim of this study was to evaluate whether the antioxidant activity and tannin concentrations in the stem bark of Spondias tuberosa Arruda (Anacardiaceae) varied with collection site.Material and methods: The bark was collected from 25 individual trees, distributed in five different landscape units, as follows: agroforestry gardens, areas of pastures, maize cultivation areas, mountain areas and mountain bases, with the former 3 being considered as anthropogenic habitats, and the latter 2 considered as habitats with native coverage. The study was conducted in the rural area of the city of Altinho, Pernambuco State (Northeast Brazil). The DPPH (1,1-diphenyl-2-picrylhydrazyl) method was used to measure the antioxidant activity and tannin concentrations were evaluated by using the radial diffusion method.Results: The results demonstrated ...

Natural products from ethnodirected studies: revisiting the ethnobiology of the zombie poison.

Wade Daviss study of Haitian “zombification” in the 1980s was a landmark in ethnobiological research. His research was an attempt to trace the origins of reports of “undead” Haitians, focusing on the preparation of the zombification poison. Starting with this influential ethnopharmacological research, this study examines advances in the pharmacology of natural products, focusing especially on those of animal-derived products. Ethnopharmacological, pharmacological, and chemical aspects are considered. We also update information on the animal species that reportedly constitute the zombie poison. Several components of the zombie powder are not unique to Haiti and are used as remedies in traditional medicine worldwide. This paper emphasizes the medicinal potential of products from zootherapy. These biological products are promising sources for the development of new drugs.

Information Retrieval during Free Listing Is Biased by Memory: Evidence from Medicinal Plants

Free listing is a methodological tool that is widely used in various scientific disciplines. A typical assumption of this approach is that individual lists reflect a subset of total knowledge and that the first items listed are the most culturally important. However, little is known about how cognitive processes influence free lists. In this study, we assess how recent memory of use, autonoetic and anoetic memory, and long-term associative memory can affect the composition and order of items in free lists and evaluate whether free lists indicate the most important items. Based on a model of local knowledge about medicinal plants and their therapeutic targets, which was collected via individual semi-structured interviews, we classify each item recorded in free lists according to the last time that the item was used by the informant (recently or long ago), the type of relevant memory (autonoetic or anoetic memory) and the existing associations between therapeutic targets (similar or random). We find that individuals have a tendency to recall information about medicinal plants used during the preceding year and that the recalled plants were also the most important plants during this period. However, we find no trend in the recall of plants from long-term associative memory, although this phenomenon is well established in studies on cognitive psychology. We suggest that such evidence should be considered in studies that use lists of medicinal plants because this temporal cognitive limit on the retrieval of knowledge affects data interpretation.