Structural characterisation and anti-hepatoma activities of an acidic polysaccharide extracted from Morinda citrifolia L. (Noni) fruits

Noni (Morinda citrifolia L.), a traditional edible and medicinal plant, has health-promoting, anti-tumour potential. An acidic heteropolysaccharide, NONI-E2, was flash-extracted from noni fruits under optimised conditions (70 °C, 60:1 mL/g, 110 V, 50 s), yielding 16.08%. Purified NONI-E2 (16.7%) had a 28.26 kDa molecular weight, mainly contained galactose, xylose, and glucuronic acid, and showed pyranose rings, flocculent coral-like amorphous nanostructure, and Congo-red-indicated ordered conformation. It significantly inhibited tumour cells, especially HepG2 hepatoma cells, via mitochondrial depolarisation, Bcl-2/Bax modulation, and Caspase 8/12 activation, triggering extrinsic and intrinsic apoptosis. NONI-E2 is a promising anti-hepatoma agent for functional food or natural anticancer development.