Characterization of hemicelluloses from Neolamarckia cadamba (Rubiaceae) during xylogenesis

•Molecular structures of hemicelluloses extracted from N.cadamba were investigated synergistically.•(4-O-methyl) glucuronoxylan is the main type of hemicelluloses in N. cadamba..•The chain conformation of hemicelluloses extracted from N.cadamba were elucidated. In this study, hemicelluloses were isolated from the apical, middle and basal segments of N. cadamba using a 2N KOH extraction procedure. Chemical composition and structural characterization of the three hemicellulosic fractions obtained were comparatively investigated by a combination of HPLC, GPC, FTIR, 1H,13C, HSQC NMR and TGA techniques. According to the sugar analysis and spectral results, (4-O-methyl) glucuronoxylan was the primary hemicellulose identified in the samples with trace levels of mannan also present. All of the three samples showed spherical polymers in 0.005M sodium phosphate solution (containing 0.02N NaCl). Xylan in the middle and basal segment stems had higher molecular weights. Our findings show that during xylogenesis in N. cadamba, changes are observed in xylan content and molecular weight.