Xylogalacturonan-enriched pectin from the fruit pulp of Adansonia digitata: Structural characterization and antidepressant-like effect

Abstract

The low methyl-esterified and acetylated xylogalacturonan (DM 20 %, DA 2 %, Mw ∼ 58 kDa) was isolated by water extraction for 4 h × 2 at 50 °C (yield 23 %) from the pulp of baobab fruit (Adansonia digitata L.). Subsequent tightening of the conditions for water extraction by mean increasing the temperature to 70 °C and time to 12 h led to the co-extraction of small amounts of starch components and RG I with xylogalacturonan. Structural analysis (DEAE-cellulose ion-exchange chromatography, HPSEC, monosaccharide analysis, NMR spectroscopy) revealed that about 12 mol. % of 1,4-linked α-GalpA residues were substituted by single β-Xylp residues at the O-3 position. The xylogalacturonan was found to possess an antidepressant-like effect in mice. The study offers using the baobab fruit as a rich source of soluble dietary fiber – water-soluble pectin with beneficial physiological effect.