Isolation, partial characterisation of antithiamine factor present in rice-bran and its effect on TPP-transketolase system and Staphylococcus aureus.

1. A light yellow viscous oily antithiamine compound designated as Compound X was isolated from rice-bran and it was composed of three components--glucose, a yellow viscous oily substance (Fraction A) and a reddish brown amorphous substance (Fraction B). 2. 1 mg of Compound X inactivated 3.5 microgram of thiamine hydrochloride whereas 1 mg of Fraction A inactivated 26.5 microgram of thiamine hydrochloride. Fraction B had no antithiamine activity. 3. Fraction A was partially characterised as benzene nucleus with ortho dihydroxyl groups, one methyl group and a side chain containing hydroxyl and carboxylic acid groups. 4. Compound X as well as Fraction A inhibited the utilisation of ribose-5-phosphate by TPP-TK system of human erythrocyte hemolysate and the growth of Staphylococcus aureus was retarded by these compounds.