Maytenus ilicifolia, commonly known as "espinheira-santa", is a plant found in the Southern region of Brazil, and also in Paraguay, Uruguay and Argentina. The infusion of its leaves is mainly used for the treatment of gastric ulcers. Dried ground leaves (2 kg) were submitted to infusion extraction, from which an arabinogalactan was isolated as the major polysaccharide. An aliquot of the  infusion residue (730 g) was defatted with CHCl₃:MeOH (2:1 v/v), and then extracted with H₂O under reflux (3 h, x3). This extract was treated with x3V EtOH, resulting in crude polysaccharides precipitated (9 g). This mixture was submitted to freeze-thawing until precipitation ceased, and the chilled water-soluble portion (7.5 g) was treated with Fehling solution, yielding a precipitate (PEEAsp, 2.3 g) composed of a homogeneous polysaccharide (12,230 g/mol and dn/dc = 0.223), according to HPSEC analysis. PEEAsp contained uronic acid:Ara:Gal:Rha:Glc in an 80:9:7:2:2 molar ratio, determined by GC-MS analysis (the uronic acid was estimated colorimetrically, using m-hydroxydiphenyl). Carboxyl-reduction of PEEAsp showed that the uronic acid present is GalA, and ¹³C-NMR analysis of PEEAsp indicated only six signals at d 175.1, 98.6, 78.0, 71.3, 69.0, 68.4, attributed to C-6 (carboxyl group), C-1, C-4 substituted, C-5, C-3, e C-2, respectively. Methylation analysis of carboxyl-reduced PEEAsp showed 2,3,6-Me₃-Galp as the main derivative (83%). We thus conclude that PEEAsp is a galacturonan formed of a-GalpA (1®4)-linked units. Neutral monosaccharides could be derived from other polysaccharides also present in lesser amounts.

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