Spinosad is a naturally-occurring insecticide found in the the soil bacterium
S. spinosa.
1 It is a mixture of the macrocyclic lactones spinosyn A (Item No.
16528) and spinosyn D (Item No.
19158), which act as agonists of insect nicotinic acetylcholinesterase receptors (nAChRs). Oral administration of spinosad induces toxicity in fruit flies including
C. capitata, B. curcurbitae, and
B. dorsalis (LC
50s = 2.8-4.2, 4.3-5.5, and 3.1-3.3 μg/ml, respectively) but has low toxicity in vertebrates.
2,3,4 It also inhibits canine P-glycoprotein (P-gp; IC
50 = 0.2 μg/ml).
5 Formulations containing spinosad have been used in the agricultural and veterinary control of insects.
