On some constituents showing positive reaction by Ehrlich's aldehyde reagent in brown-rotted tissues of sweet potato.

Abstract

Sweet potatoes are often brown-rotted as a result of infection by Helicobasidum mompa TANAKA, Ceratostomella fimbriata (E. et H.) ELL, or Thielavia basicola ZOPF.
When a section of the affected tissue is mounted in EHRLIOH'S aldehyde reagent, a red color develops in the browned tissue and its periphery. An oily substance giving the same coloration with the reagent has been isolated from the browned tissues. The results of analysis of the oily substance, show that the latter consists of two compounds, the one, ipomoeamaron, first described by HIURA in 1943(3) as a sesquiterpene, having a formula C₁₅H₂₂O₃, and the other, a terpene having a lower boiling point; both reacting positive with the reagent. The occurrence of these substances is usully accompanied with the browning of tissues.
The oily substance may play a roll in the resistance of the host tissue against the invasions of the above pathogens.