Preparation and some properties of low-molecular-weight selenotrisulfide compounds and selenium-containing, high-molecular-weight, heparin-related compounds

Low-molecular-weight selenotrisulfide (SeT) compounds were prepared by the reaction of thiol compounds [monothiols: thiosalicylic acid (TSA) and diethyldithiocarbamic acid (DDC); dithiols: dimercaptosuccinic acid, dithiothreitol and dithioerythritol] and selenious acid. For TSA, a SeT compound was isolated by preparative high-performance liquid chromatography (HPLC) and the reaction molar ratio of this thiol to seleniuous acid was analyzed by HPLC. A simple method for the preparation of DDC-SeT from DDC sodium salt and selenious acid was developed, by which pure DDC-SeT could be isolated without any further purification processes. Similar SeT compounds were prepared from other dithiocarbamate derivatives. The SeT compounds were also prepared from dithiols. It was shown that the reaction molar ratios of dithiol compounds to selenious acid were not always 2 : 1. For a high-molecular-weight selenium compound, a heparin-selenocystamine conjugate (Hep-SeCyst) was prepared. After the oxidation of heparin with periodate, selenocystamine (SeCyst) was introduced into the heparin molecule. The selenium content in the conjugate was approximately 1%, and it was determined that the conjugate contains selenol groups or groups that can be converted to selenol. Similar high-molecular-weight selenium compounds were prepared from dextran and dextran sulfate. Hep-SeCyst exhibited antioxidative activities in a few in vitro systems.