METAL-CONTAINING COMPONENTS IN MEDICINAL-PLANTS .3. MANGANESE-CONTAINING COMPONENTS IN THEAE-FOLIUM AS ORAL MAGNETIC-RESONANCE-IMAGING CONTRAST MATERIALS

A manganese-containing component from the water-extract of Theae foliu m (green tea) was found to exert an augmentative effect in magnetic re sonance imaging (MRI) contrast and may possibly be a manganese(II) com plex with st pectin-like polysaccharide capable of shortening the spin -lattice relaxation time (T-1) of water protons, Even though only the manganese(II) ion with S=5/2 is active in T-1-shortening ability, whic h should enhance contrast, complexation of this ion with the polysacch aride causes a marked increase in its activity, This manganese-contain ing pectin-like polysaccharides should prove useful as a low-toxic ora l gastrointestinal contrast material in MRI.