Copaifera langsdorffii Bark as a Source of Chemicals: Structural and Chemical Characterization

Abstract

The chemical composition and the anatomy of Copaifera langsdorffii bark are reported here for the first time by studying trees grown in a native forest area in the Amazon region, Brazil. The bark is thin, dark reddish brown, and exfoliates in irregular flakes. It is very dense, showing highly lignified cells and abundant sclereids, and cellular fillings of phenolic nature. It includes a poorly developed rhytidome and a periderm with thin- and thick-walled phellem cells. The mean chemical composition was: ash 3.7%, total extractives 21.3%, mainly corresponding to polar compounds soluble in ethanol and water, suberin 0.8%, and lignin 36.6%. The polysaccharides showed a predominance of glucose and xylose (66.4% and 23.5% of total monosaccharides, respectively). The ethanol-water bark extract had a high content in phenolics: total phenolics 589.2 mg gallic acid/g extract, flavonoids 441.9 mg catechin/g extract, and tannins 54.8 mg catechin/g extract. The antioxidant activity was high, comparable to known antioxidant reference compounds: 720.3 mg Trolox per g of extract or 92.1 mg Trolox per g of bark. After bark grinding, the finest fraction was enriched in polar extractives (40.6%). C. langsdorffii bark is a potential source of functional extractives, therefore representing a valorization of the residual bark obtained during the industrial tree processing for timber.