Patent ID: 7244462

Claim:
An isolated amino acid derivative, or salt form thereof, represented by formula (1): wherein R 1 represents any substituent selected from the group consisting of a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a hydroxylalkyl group having 1 to 3 carbon atoms; R 2 represents any substituent selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, a hydroxylalkyl group having 1 to 3 carbon atoms, a carbamoyl group, a carbamoyl group having an alkyl having 1 to 3 carbon atoms, and a carboxyl group; and R 3 represents a substituent represented by formula (2): wherein R a , R b , R c , R d , and R e each independently represent any substituent selected from the group consisting of a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, and an alkoxy group having 1 to 3 carbon atoms; R b and R c , and/or R d and R e may together form an alkylene group having 1 to 4 carbon atoms, respectively, with the proviso that however compounds concurrently having R 1 of a hydroxyl group, R 2 of a carboxyl group, and R 3 of a 3-indolylmethyl group in the formula (1) are excluded from said derivative.