Ryania insecticide: analysis and biological activity of 10 natural ryanoids

Phillip R. Jefferies, Robert F. Toia, Brian Brannigan, Isaac N Pessah, John E. Casida

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36 Scopus citations


Ryania insecticide, the powdered stemwood of Ryania speciosa, was analyzed by HPLC and 1H NMR for the content (ppm, w/w) of 10 ryanoids. The compounds were isolated and their potencies compared for toxicity to housefly adults (injection, piperonyl butoxide as a synergist), flour beetle larvae (dietary exposure), and mice (intraperitoneal) and for competition with [3H]ryanodine for binding to the Ca2+ release channel complex. Ryanodine (range 450-600 ppm) and 9,21-dehydroryanodine (650-700 ppm) are essentially equipotent and account for almost all of the biological activity of ryania in each of these systems. 9-Hydroxy-10-epiryanodine (7-17 ppm) and three 8ax-hydroxy-10-epiryanodine derivatives [10-(O-methyl) (28-33 ppm), dehydro (30-64 ppm), and 10-(O-methyl)dehydro (22-32 ppm)] are very effective with houseflies but not in the other assays. 18-Hydroxyryanodine (<10 ppm), ryanodyl 3-(pyridine-3-carboxylate) (42-58 ppm), 8ax,18-dihydroxy-10-(O-methyl)-10-epiryanodine (5-10 ppm), and 9-hydroxyanhydroryanodine (12-17 ppm) are all of low activity. The potency of a ryanoid at the Ca2+ release channel is a better predictor of toxicity to mice and beetle larvae than to housefly adults.

Original languageEnglish (US)
Pages (from-to)142-146
Number of pages5
JournalJournal of Agricultural and Food Chemistry®
Issue number1
StatePublished - 1992

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Food Science
  • Chemistry (miscellaneous)


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