Comparison of the immunological activities of arabinoxylans from wheat bran with alkali and xylanase-aided extraction

Differences in immunoregulatory activities of arabinoxylans (AXs) from wheat bran extracted by alkaline- and enzyme-based methods are unknown. We extracted AX from wheat bran by the 2 procedures. Chemical analysis revealed that alkaline-extracted AX (AX(A)) contained a lower amount of protein (4.10%) than enzyme-extracted AX (AX(E), 9.85%) and no ferulic acid (as compared with 43.5 mg/100 g in AX(E)). AX(A) consisted of a highly substituted population with a ratio of arabinose to xylose of 0.83 (AX(E): 0.56), meanwhile the weight-average molecular weight of AX(A) (3.517 x 10(5) Da) was about 10 times that of AX(E) (3.252 x 10(4) Da). Both AX(A) and AX(E) had potent stimulating effects on innate and acquired immune responses on oral administration in female BALB/c mice. AX(E) showed higher macrophage phagocytosis and delayed hypersensitivity reaction than did AX(A), with no significant differences in enhancing lymphocyte proliferation. Whether extracted by alkaline- or enzyme-aided methods, the obtained AXs could be explored as potent natural immunomodulators. (C) 2010 Elsevier Ltd. All rights reserved.