A Polysaccharide from a Tea (Infusion) of<i>Maytenus</i><i>i</i><i>licifolia</i>Leaves with Anti-ulcer Protective Effects

Abstract

Maytenus ilicifolia is a medicinal plant used as a tea (infusion) for treatment of stomach ulcers. This tea furnished a polysaccharide after several purification steps, consisting of a freezing-thawing process, Fehling precipitation, ultrafiltration, and dialysis. It consisted of arabinose, galactose, galacturonic acid, 4-O-methylglucuronic acid, rhamnose, and glucose in a 42:41:6:5:4:2 molar ratio. Methylation analysis, controlled Smith degradation, and NMR spectroscopy indicated that it was a type II arabinogalactan containing a (1-->3)-linked beta-d-Galp main chain, substituted at O-6 by (1-->6)-linked beta-d-Galp chains, which were mainly substituted at O-3 by (1-->5)- and (1-->3)-linked alpha-l-Araf chains, and nonreducing end-units of alpha-l-Araf and 4-O-Me-GlcpA. This polysaccharide significantly inhibited ethanol-induced gastric lesions in rats with an ED(50) of 9.3 mg/kg, suggesting that the arabinogalactan liberated from the infusion has a protective anti-ulcer effect.