Indospicine, a Hepatotoxic Amino Acid from Indigofera Spicat A: Isolation, Structure, and Biological Studies

Abstract

Indospicine (L-2-amino-6-amidinohexanoic acid) has been newly characterized as a component of a higher plant, being isolated from the leaves and seeds of Indigofera 8picata. Indospicine was hydrolysed in distilled water at 120°C to 2-aminopimelamic acid and ammonia (1 mole). Mild acid hydrolysis of the latter compound yielded optically pure L-oc-aminopimelic acid. The infrared, nuclear magnetic resonance, and mass spectra of indospicine and of its degradation products supported the proposed structure. When injected subcutaneously into mice (1 mg/g body weight) indospicine produced fat accumulation and cytologioal ohanges in the liver. The fat aocumulation was inhibited by simultaneous injeotion of arginine but not by oanavanine. A substantial part of the hepatotoxioity of extracts of 1. 8picata seed was accounted for in terms of indospicine. The ooncentration of indospicine in the seeds exoeeded that in the leaves and stems of the plant.