Structure and biological activities of hypochlorite oxidized zymosan

Zymosan (ZMI), a strong complement activating yeast cell preparation, is also a potent inflammatory substance, which shows immunopharmacological activity. Major component of ZYM is beta -glucan but contains other constituents, such as mannan, protein, and nucleic acid. We applied sodium hypochlorite (NaClO) treatment to ZYM to reduce impurities and compared the activity with native/parent ZYM. Oxidized ZYM (OX-ZYM) became a nitrogen-free agent. By NMR analysis of native OX-ZYM and zymolyase (endo-1,3-beta -glucanase) digest, OX-ZYM was found to contain 1,3-beta -linked and 1,6-beta -linked glucan moieties, while the latter degraded by sodium metaperiodate treatment. OX-ZYM also contained small amounts of anionic groups, partly reducible by sodium borohydride. Degree of polymerization (DP) of 1,6-beta -glucan moiety was estimated to be about DP10-DP50 by MALDI-TOF-MS analysis. In comparison with ZYM activities, OX-ZYM and derivatives showed strong antitumor activity to solid form of Sarcoma 180 in mice, and showed strong activity on alternative pathway of complement, but lost secondary response to ZYM-immune mice. These facts strongly suggested that a particulate form of beta -glucan was prepared by NaClO treatment of ZYM and at least a part of ZYM-mediated biological activity was found unmediated by beta -glucan moiety. (C) 2001 Elsevier Science Ltd. All rights reserved.