Wood anatomical features and chemical composition of prosopis kuntzei from the paraguayan chaco

Abstract

Anatomical features for Prosopis kuntzei Harms were studied by light and scanning electron microscopy. The wood is mainly diffuse-porous with indistinct growth ring boundaries. Vessel diameter ranges between 11 to 193 μn. The thick-walled fibres average 1275 μm in length. Parenchyma bands are 66 to 1066 μm apart. Heartwood extractives were studied in the vessels, rays and part of the fibres by means of scanning UV microspectrophotometry. The pyrolytic lignin content is 30.7%. The percentage of polyphenolic compounds, such as flavonoids, hydrolysable tannins and proanthocyanidins, is comparatively high at 5.8 %. Total extract contents were determined after organic solvent extractions (23.2 %) and water extractions (24.9%). The FTIR spectroscopy showed nearly identical spectra for the methanol and water extracts, with characteristic absorption bands for aromatic substances at 1615 and 1520 cm-1. The spectrum of the acetone extract differs only due to an additional but distinct absorption in the carbonyl range at 1695 cm-1. GC/MS analyses revealed that in the acetone and methanol extracts, tetrahydroxy-flavan-3-ols (isomers of catechin and epicatechin) were the main constituents with a ratio of 25.3 and 27.6%.