Characterization of hemicelluloses from Neolamarckia cadamba (Rubiaceae) during xylogenesis

In this study, hemicelluloses were isolated from the apical, middle and basal segments of N. cadamba using a 2 N 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 0.005 M sodium phosphate solution (containing 0.02 N 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.