TY - JOUR
T1 - Characterization of furanocoumarin metabolites in parsnip webworm, Depressaria pastinacella
AU - Nitao, James K.
AU - Berhow, Mark
AU - Duval, Sandra M.
AU - Weisleder, David
AU - Vaughn, Steven F.
AU - Zangerl, Arthur
AU - Berenbaum, M. R.
N1 - Funding Information:
Acknowledgments—We thank Mark Carroll for providing webworms at critical times during the project. This work was supported in part by NSF DEB990387 to M.R.B. and A.R.Z.
PY - 2003/3/1
Y1 - 2003/3/1
N2 - Although metabolites of furanocoumarins have been characterized in a wide range of organisms, to date they have been identified in only a single insect species, Papiliopolyxenes. Depressariapastinacella, the parsnip webworm, like P. polyxenes a specialist on Apiaceae, routinely consumes plant tissues higher in furanocoumarin content than does P. polyxenes and is capable of faster cytochrome P-450-mediated detoxification of these compounds. In this study, we characterized metabolites of xanthotoxin, a linear furanocoumarin, and sphondin, an angular furanocoumarin, in midguts and frass of parsnip webworms. Two metabolites were isolated and identified from webworms fed artificial diet containing xanthotoxin. LC-ESI-MS analysis resulted in the determination of a MW of 266 for the compound in the frass and one of the compounds in the midgut; 1H NMR confirmed its structure as 6-(7-hydroxy-8-methoxycoumaryl)hydroxyacetic acid (HCHA). The second compound from the midgut had a MW of 252 and was identified by 1H NMR and 13C NMR analysis as 6-(7-hydroxy-8-methoxycoumaryl)-hydroxyethanol) (HMCH). Whereas HCHA has been found in frass of Papilio polyxenes fed xanthotoxin, HMCH has not been reported previously in insects. Although the first step of metabolism of xanthotoxin in webworms as well as P. polyxenes is likely the formation of an epoxide on the furan ring, angular furanocoumarin metabolism in webworms appears to differ. The principal metabolite of sphondin was identified as demethylated sphondin (6-hydroxy-2H-furo[2,3-h]-1-benzopyran-2-one) by LC-ESI-MS and confirmed by 1H NMR and 13C NMR analyses. That webworms produce metabolites of xanthotoxin in common not only with other Lepidoptera (e.g., HCHA) but with other vertebrates (e.g., HMCH) suggests a remarkable conservatism in the metabolic capabilities of cytochrome P-450s and raises the possibility that insects may share other detoxification reactions with vertebrates with respect to toxins in foodplants.
AB - Although metabolites of furanocoumarins have been characterized in a wide range of organisms, to date they have been identified in only a single insect species, Papiliopolyxenes. Depressariapastinacella, the parsnip webworm, like P. polyxenes a specialist on Apiaceae, routinely consumes plant tissues higher in furanocoumarin content than does P. polyxenes and is capable of faster cytochrome P-450-mediated detoxification of these compounds. In this study, we characterized metabolites of xanthotoxin, a linear furanocoumarin, and sphondin, an angular furanocoumarin, in midguts and frass of parsnip webworms. Two metabolites were isolated and identified from webworms fed artificial diet containing xanthotoxin. LC-ESI-MS analysis resulted in the determination of a MW of 266 for the compound in the frass and one of the compounds in the midgut; 1H NMR confirmed its structure as 6-(7-hydroxy-8-methoxycoumaryl)hydroxyacetic acid (HCHA). The second compound from the midgut had a MW of 252 and was identified by 1H NMR and 13C NMR analysis as 6-(7-hydroxy-8-methoxycoumaryl)-hydroxyethanol) (HMCH). Whereas HCHA has been found in frass of Papilio polyxenes fed xanthotoxin, HMCH has not been reported previously in insects. Although the first step of metabolism of xanthotoxin in webworms as well as P. polyxenes is likely the formation of an epoxide on the furan ring, angular furanocoumarin metabolism in webworms appears to differ. The principal metabolite of sphondin was identified as demethylated sphondin (6-hydroxy-2H-furo[2,3-h]-1-benzopyran-2-one) by LC-ESI-MS and confirmed by 1H NMR and 13C NMR analyses. That webworms produce metabolites of xanthotoxin in common not only with other Lepidoptera (e.g., HCHA) but with other vertebrates (e.g., HMCH) suggests a remarkable conservatism in the metabolic capabilities of cytochrome P-450s and raises the possibility that insects may share other detoxification reactions with vertebrates with respect to toxins in foodplants.
KW - Cytochrome P-450
KW - Depressaria pastinacella
KW - Furanocoumarin metabolites
KW - Insect-plant interactions
KW - Papilio polyxenes
KW - Sphondin
KW - Xanthotoxin
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U2 - 10.1023/A:1022872704016
DO - 10.1023/A:1022872704016
M3 - Article
C2 - 12757327
AN - SCOPUS:0242416964
SN - 0098-0331
VL - 29
SP - 671
EP - 682
JO - Journal of Chemical Ecology
JF - Journal of Chemical Ecology
IS - 3
ER -