Publication: Quinone reductase inducers in Azadirachta indica A. juss flowers, and their mechanisms of action
Issued Date
2005-01-01
Resource Type
ISSN
2476762X
15137368
15137368
Other identifier(s)
2-s2.0-32944477098
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Mahidol University
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SCOPUS
Bibliographic Citation
Asian Pacific Journal of Cancer Prevention. Vol.6, No.3 (2005), 263-269
Suggested Citation
Hathaitip Sritanaudomchai, Thanit Kusamran, Worapun Kuakulkiat, Nuntavan Bunyapraphatsara, Ankana Hiransalee, Anong Tepsuwan, Wannee R. Kusamran Quinone reductase inducers in Azadirachta indica A. juss flowers, and their mechanisms of action. Asian Pacific Journal of Cancer Prevention. Vol.6, No.3 (2005), 263-269. Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/16401
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Title
Quinone reductase inducers in Azadirachta indica A. juss flowers, and their mechanisms of action
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Abstract
We have previously shown that the flowers of neem tree (Azadirachta indica A. Juss, family Meliaceae), Thai variety, strongly induced the activity of glutathione S-transferase (GST) while resulting in a significant reduction in the activities of some cytochrome P450-dependent monooxygenases in rat liver, and possess cancer chemopreventive potential against chemically-induced mammary gland and liver carcinogenesis in rats. In the present study, 2 chemicals possessing strong QR inducing activity were fractionated from neem flowers using a bioassay based on the induction of QR activity in mouse hepatoma Hepa 1c1c7 cultured cells. Spectroscopic characteristics revealed that these compounds were nimbolide and chlorophylls, having CD (concentration required todouble QR specific activity) values of 0.16 and 3.8 μg/ml, respectively. Nimbolide is a known constituent of neem leaves, but was found for the first time here in the flowers. Both nimbolide and chlorophylls strongly enhanced the level of QR mRNA in Hepa 1c1c7 cells, as monitored by northern blot hybridization, indicating that the mechanism by which these constituents of neem flowers induced QR activity is the induction of QR gene expression. These findings may have implication on cancer chemopreventive potential of neem flowers in experimental rats previously reported.