Abstract
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 language | English (US) |
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Pages (from-to) | 142-146 |
Number of pages | 5 |
Journal | Journal of Agricultural and Food Chemistry® |
Volume | 40 |
Issue number | 1 |
State | Published - 1992 |
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)
- Food Science
- Chemistry (miscellaneous)