CInomatographic Investigations of Indole Compounds 81 



acetic acid showed that the compound occurring at low Rf possessed 

 growth-promoting activity (Figure 2), a result which is consistent with 

 the activity previously reported for authentic indole-3-acetylaspartic 

 acid (1) . With the ethyl-acetate extraction technique used in this se- 

 ries of experiments, it has been possible to demonstrate the presence 

 of one or more of these aspartic acid condensation products in the 

 extracts of all the pea-treated indole acids, except in that obtained 

 from indole-3-carboxylic acid. Thus, in addition to the metabolites 

 produced in the (3-oxidative degradation of these acids in pea tissue, 

 all the higher homologues yielded small blue spots with low Rf val- 

 ues which corresponded chromatographically with either indole-3- 

 acetyl- or indole-3-propionylaspartic acids (Figure 1). 



co-(Indole-3-)alkanecarbonaniides 



With the exception of indole-3-carbonamide, all members of this 

 series showed growth-promoting activity in the three tests employed 

 (Table 2). Such activity is consistent with hydrolysis of these amides 

 with the test tissue to the corresponding carboxylic acid, which may 

 then be active per se or converted to an active product by (3-oxida- 

 tion. Although no conversion of amide to acid occurred in the ab- 

 sence of tissue, clear evidence for this was found on the chromato- 

 grams obtained from metabolism experiments with both wheat and 

 pea tissues (Figure 3) and from the bioassay results of comparable 

 chromatograms (Figure 4). Thus, the chromatogram of metabolized 

 acetamide and jjropionamide showed distinct blue spots (at Rf 0.24 

 and 0.30) when sprayed with Ehrlich's reagent, which corresponded 

 respectively to indole-3-acetic and (3-(indole-3-) propionic acids. Each 

 chromatogram also showed a second spot with a high Rf value which 

 represented the unchanged amide present in the extract. The metab- 

 olized butyramide and valeramide yielded three large blue spots on the 

 chromatograms which corresponded with three major peaks of 

 activity in the bioassay results. In the case of the butyramide, the first 

 two spots correspond respectively to indole-3-acetic and -butyric acids, 

 whereas the third spot near the solvent front was the residual amide. 

 Similarly, on the valeramide chromatograms, the first two major spots 

 correspond respectively to indole-3-propionic and -valeric acids and 

 the third spot was again due to the residual amide. This amide also 

 yielded appreciable quantities in the extracts from both wheat and 

 pea-treated solutions of the unknown acidic compound at Rf 0.25 

 which gave a distinct greenish-orange spot with Ehrlich's reagent. 

 The presence of aspartic acid conjugation products with low Rf val- 

 ues was again observed on the chromatograms from pea metabolism 

 experiments (Figure 3). 



