Toxic Constituents of Rayless Goldenrod

Abstract

Bacillus cereras has been found to be an excellent assay organism in the study of the toxin isolated from rayless goldenrod. Two compounds which inhibit the growth of Bacillus cereus have been isolated from the crude toxin. One of these, dehydrotremetone (2-isopropenyl-5-acetylbenzofuran) recently has been reported to occur in white snakeroot, a poisonous plant that produces symptoms in higher animals similar to those produced by rayless goldenrod. The second, more abundant and more toxic compound, toxol, has not been reported previously. Toxol is shown to be optically active 2-isopropenyl-3-hydroxy-5acetyi-2,3-dihydrobenzofuran.(1) This investigation was generously suppurto*d by tin* National Institutes of Health through research grant RG-8346.(2) To whom inquiries should be sent.(3)

Experimental Rayless Goldenrod (Isocoma pluriflora) Toxicosis in Goats

“…Various toxins have been described in rayless goldenrod 3,5,6,9,16 . In addition to the previously mentioned tremetol, 5,6 several monoterpenes, sesquiterpenes, 16 and essential oils 3 have also been described. In vitro studies using a tremetol mixture suggests that at least 1 component of this mixture or of its metabolites inhibits oxidative phosphorylation, most likely by inhibiting the tricarboxylic acid cycle 15 .…”

“…Rayless goldenrod is a known toxic plant and has a history of sporadically poisoning livestock for more than 100 years 4,10 . Various toxins have been described in rayless goldenrod 3,5,6,9,16 . In addition to the previously mentioned tremetol, 5,6 several monoterpenes, sesquiterpenes, 16 and essential oils 3 have also been described.…”

Phytotoxic activities of (2R)-6-hydroxytremetone

“…suggest that the phytotoxic effects of (2R)-6-hydroxytremetone is not mediated by a competition with cytokinins, as previous studies reported growth inhibition on bacteria, whose cellular division is not dependent on cytokinin production [7]. This interference probably endows hydroxytremetone-producing plants with the advantage to invade new niches such as wild environments, or to compete with traditional crops.…”

Naturally Occurring Benzofurans

“…and its oxime, as well as thier two C-methyl groups and optical inactivity suggest this ketone is the completely unsaturated analog of tremetone (23). Dehydrotremetone (24) has been synthesized by Horton et Acetylation of methyl benzofuran-2carboxylate with acetyl chloride in presence of aluminum chloride gave methyl 5-acetylbenzofuran-2-carboxylate (28); its ethylene ketal, 29. As with tremetone, ozonization of 24 afforded benzaldehyde; catalytic hydrogenation resulted in the uptake of two moles of hydrogen and formation of dihydrotremetone (25), structurally identical with the product isolated by hydrogenation of tremetone.…”