Mutagenicity, kaempferol

The plant is known elaborate a series of quite unusual phenanthrene alkaloid derivatives, of which aristoliukine-C, aristofolin A and E, aristolochic acid-la methyl ester, and aristolochic acid. Other chemical constituents found in this plant are flavonoid glycosides such as kaempferol-3-O-rutinoside and quercetin kaempferol-3-O-rutinoside (3,4). Exposure to Aristolochiaceae family is associated with the development of cancer in humans. A significant advance is the toxicological effects of aristolochic acid has been provided by the work of Pezzuto et al. They showed that aristolochic acid is a mutagen... 

Quercetin (2) is easily the most active flavonol in the Salmonella test, yet it is at least an order of magnitude less potent than such familiar mutagens as benz[a]pyrene and chrysene. Quercetin, galangin (6), kaempferol (7) and rhamnetln (3) are more or less active in several other in vitro tests designed to detect genetic toxicity. For example, quercetin has been shown to transform hamster embryo cells (kaempferol did not)... 

Mutagenic activity of a food colorant derived from hibiscus was observed in the Ames assay in Salmonella typhimurium strains TA98 and TAIOO with or without activation by S9. The compounds responsible for the mutagenic activity were identified as kaempferol and/or quercetin (Takeda and Yasui 1985). Although quercetin has been shown to have mutagenic activity in vitro, in vivo tests indicate a lack of mutagenicity in animals (Harwood et al. 2007). 

The structural requirements for 8-hydroxyflavone activation are distinct from those for flavonols such as quercetin or kaempferol. Whereas B-ring hydroxylation, 2,3-unsaturation, and 3-hy-droxylation appear critical for flavonol mutagenicity, the B-ring and 2,3-positions do not appear to be involved in the activation of 8-substituted flavones. The 5,7,8-substitution pattern on the A-ring is particularly effective at conferring high activity in the flavone series. The seven most active compounds known at present all have -OH or -OCH substituents at these positions. 

Maruta, A., Enaka, K. and Umeda, H. (1979). Mutagenicity of quercetin and kaempferol on cultured mamnalian cells. Gann 70, 273-276. 

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