STUDIES ON THE THERMOSTABLE ANTITHIAMINE FACTOR : (II) THIAMINE DECOMPOSING SUBSTANCES OF HORSETAIL : THE BASIDIUM OF EQUISETUM ARVENSE L.

Abstract

In order to study the thermostable antithiamine factor (SF) of horsetail, the thiamine decomposing activities of paper chromatograms of horsetail extract were estimated and it was found that two pigments and some fluorescent substances had a strong activity. From ethyl acetate fraction of alcoholic extract of horsetail, yellow needle crystals, i. e., articulatin (C_<20>H_<18>O_<12>・2H_2O, m.p. 191°), was isolated. When articulatin was hydrolysed, yellow needles, i e., articulatidin (C_<l4>H_6O_7・l^I/2H_2O, m.p. 291-293°), and glucose were produced. It is, therefore, supposed that articulatin was pentahydroxyanthraquinone-glucoside. Because articulatin and articulatidin had a strong thiamine decomposing activity, a part of SF of horsetail was considered to be formed of these pigments.