Characterization and evaluation of native populations of cat's claw (Uncaria tomentosa and U. guianensis) in the valley of Juruá River, Acre, Brazil

Abstract

Among several medicinal species found in the Amazon, two stand out: Uncaria tomentosa (Willd.) D.C. and U. guianensis (Aubl.) Gmel. (Rubiaceae), both are popularly known as "cat's claw". Their medicinal properties are attributed to immune-stimulating and anti-inflammatory effects and cancerous cells growth inhibition. This work aimed to characterize and evaluate native populations of cat's claw in the Juruá River valley, seeking to estimate parameters for the elaboration of a management plan for these species. The survey and field observations were accomplished in three areas: Community Alto Pentecostes, Seringal São Salvador and Ashaninka Indigenous Reserve, located in the Municipalities of Cruzeiro do Sul, Mâncio Lima and Marechal Thaumaturgo, respectively. Samples of botanical material were collected and exsiccates were prepared for identification of species. The data collection was accomplished by randomic sampling, establishing transects in "várzea" (forest flood plain) ecosystems, "terra firme" (forest upland) and fallow (secondary forest). The results of the inventory presented a total of 374 plants in the sampled area, which corresponds to a density of 45.6 plants ha-1. From 82 sampling units established, 36 did not show any individual of the studied species and the plot of the greatest density presented a total of 33 plants. Analyzing the studied ecosystems separately, it was observed a gradient of decreasing density from forest flood plain to fallow and from fallow to forest upland. For plants with DBH (Diameter at Breast Height) from 5 to 9.9 cm the density was 14.9 individuals ha-1 and for plants with DBH from 10 to 14.9cm, 0.97 individuals ha-1. Using 5 cm DBH as minimum limit for cutting, there will be an average of 16 individuals ha-1 of both species, available for cutting. Considering the plant density present in the studied areas, the estimated production for dry bark of cat's claw could be around 13.26 kg ha-1 for U. tomentosa and 199 kg ha-1 for U. guianensis.