Arabinogalactan in banana: Chemical characterization and pharmaceutical effects

It is generally recognized that banana has diverse health benefits. However, most of the molecules responsible for the health benefits remain unknown. In this work, an important polysaccharide was extracted from banana and purified. The molecular weight was determined to be 526.2 kDa. It was identified by chemical and spectroscopic methods as arabinogalactan with β-D-(1→6)-galactan as backbone. This arabinogalactan was comprised of three monosaccharides, including Ara, Gal and GlcA with a relatively molar ratio of 5.8: 5.9: 1.0. The side chains were identified to be α-L-Araf-(1→, β-D-GlcpA-(1→, α-L-Araf-(1→5)-α-L-Araf-(1→ and α-D-Galp-(1→3)-α-L-Araf-(1→. They were linked to β-D-(1→6)-galactan at O-3, respectively. The putative structure was drawn as below. This arabinogalactan could induce NO production. It could also inhibit ROS production with a dose-dependent behaviour.