Induction of detoxification enzymes by quercetin in the silkworm.
Quercetin is one of the most abundant flavonoids and the defense secondary metabolites in plants. In this study, the effect of quercetin on the growth of the silkworm larvae was investigated. Cytochrome P450 monooxygenases (P450s), glutathione S-transferases (GSTs), and carboxylesterases (COE) were assayed after exposure to different concentrations of quercetin for 3 d (short-term) and 7 d (long-term), respectively. The results showed that the weight gain of the silkworm larvae significantly decreased after the larvae were treated by different concentrations of quercetin except for the treatment with 0.5% quercetin. Activities of P450, GST, and COE were induced by 0.5 or 1% concentration of quercetin. In the midgut, the induction activity of P450s was reached to the highest level (2.3-fold) by 1% quercetin for 7 d, the highest induction activities of GSTs toward CHP and CDNB were 4.1-fold and 2.6-fold of controls by 1% quercetin after 7 d exposure, respectively. For COEs, the highest activity (2.3-fold) was induced by 0.5% quercetin for 7 d. However, P450s in whole body were higher inducible activities in short-term treatment than those in long-term treatment. The responses of eight cytochrome P450 (CYP) genes belonged to CYP6 and CYP9 families and seven GST genes were detected with real-time polymerase chain reaction. In addition, the genes induced by quercetin significantly were confirmed by qRT-PCR. CYP6AB5, CYP6B29, and GSTe8 were identified as inducible genes, of which the highest induction levels were 10.9-fold (0.5% quercetin for 7 d), 6.2-fold (1% quercetin for 7 d), and 7.1-fold (1% quercetin for 7 d), respectively.
The Institute of Agricultural and Life Sciences, Chongqing University, Chongqing 400044, China.
Yue-E
YE
Zhang
Hui-Jing
HJ
Ma
Dan-Dan
DD
Feng
Xiao-Fei
XF
Lai
Zhao-Min
ZM
Chen
Ming-Yue
MY
Xu
Quan-You
QY
Yu
Ze
Z
Zhang
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D012831:Bombyx / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D043182:Carboxylesterase / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D007814:Larva / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D011794:Quercetin / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000975:Antioxidants; D003577:Cytochrome P-450 Enzyme System; D011794:Quercetin; D005982:Glutathione Transferase; D043182:Carboxylesterase