Extraction, purification, physicochemical properties and antioxidant activity of a new polysaccharide from Ocimum album L. seed

摘要

In this study, a novel polysaccharide fraction from Ocimum album seed was extracted and then purified by Cellulose DEAE-52 and Sephadex G-200 anion exchange chromatography. The structural, physicochemical and antioxidant properties of the main polysaccharide fraction (OAP-1A) were evaluated. The purified polysaccharide contained 94.3% carbohydrate, 3.56% moisture and 2.14% ash and result of gel permeation chromatography (GPC) showed average molecular weight of 593 kDa. The results of high-performance liquid chromatography (HPLC) showed that OAP-1A was a neutral hetero-polysaccharide composed of mannose (35.7%), glucose (33.32%), galactose (19.6%) and rhamnose (11.38%). In addition, GC MS data. nuclear magnetic resonance (NMR) spectrum and Fourier transform infrared (FT-IR) analysis revealed that the backbone of OAP-1A consists of -> 3)-beta-D-Manp-(1 ->, -> 3,4)-beta-D-Manp-(1 ->, -> 3,6)-beta-D-Manp-(1 ->, -> 3)-alpha-D-Glcp-(1 ->, -> 6)-beta-D-Galp-(1 ->, -> 4)-alpha-L-Rhap-(1 -> and alpha-D-Glcp-(1 ->. X-ray diffraction (XRD) analysis showed semi-crystalline structure in OAP-1A. Differential scanning colorimeter (DSC) and thermo-gravimetry analysis (TGA) indicated that OAP-1A had relatively high thermal stability. Moreover. OAP-1A showed strong scavenging activity against 2,2-diphenyl-1-piaylhydrazyl (DPPH) radicals. (C) 2021 Published by Elsevier B.V.