Isolation and partial characterization of avenacin, an antibiotic-like substance from oats

by Maizel, Jacob Valentine

Abstract (Summary)
A procedure has been described for isolation and bioassay of a potent antifungal substance from the roots of oat seedlings. The purified substance has been named avenacin. Avenacin gives half-maximal inhibition of Neurospora at a concentration of 0.4 µg/ml and has been found to inhibit a number of plant pathogenic fungi and Mycobacterium tuberculosis at various concentratio a less than 50 µg/ml. Microanalysis of avenacin has given the following composition: C, 59.28%; H, 7.75%; N, 1.41% and 0 by difference, 31.56%. The molecular weight is 1000 and the empirical formula is C44±1 H78±2 O20±1 N. The ultraviolet absorption spectrum of avenacin has maxima at 353, 255 and 222 mµ, in methanol. Alkaline hydrolysis of avenacin liberates the chromophore, N-methyl anthranilic acid, which is esterified to an aglycone in intact avenacin. Brief acid hydrolysis of avenacin liberates a mixture of oligo- and monosaccharides and a conjugate of N-methyl anthranilic acid with the aglycone. Subsequent basic hydrolysis of the conjugate frees the aglycone and N-methyl anthranilic acid. Further acid hydrolysis of the oligo- and monosaccharide fraction gives a hoxose-pentose mixture in the molar ratio of 2:l. Chromatography in methyl ethyl ketone-acetic acid water (30:3:10 v/v) did not separate the pentose from arabinose or the hexose from glucose and galactose. Evidence concerning the structure of avenacin is summarized and biological properties are discussed.
Bibliographical Information:

Advisor:Herschel K. Mitchell

School:California Institute of Technology

School Location:USA - California

Source Type:Master's Thesis



Date of Publication:01/01/1960

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