A Polysaccharide from a Tea (Infusion) of Maytenus ilicifolia 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 β-d-Galp main chain, substituted at O-6 by (1→6)-linked β-d-Galp chains, which were mainly substituted at O-3 by (1→5)- and (1→3)-linked α-l-Araf chains, and nonreducing end-units of α-l-Araf and 4-O-Me-GlcpA. This polysaccharide significantly inhibited ethanol-induced gastric lesions in rats with an ED₅₀ of 9.3 mg/kg, suggesting that the arabinogalactan liberated from the infusion has a protective anti-ulcer effect.