We have partially purified a herbal extract (which contains a mixture of flavonoids) in which we found anticancer properties. Further, we checked intracellular ROS generation doses dependently. I doubt that flavonoids are generally ROS scavengers, but in our case they are producing intracellular ROS in cancer cells. Could any one explain this to me?
Here you can find some examples of a so-called "futile" redox cycling with the formation of reactive oxygen species:
Miura, et al. 1998. Active oxygens generation by flavonoids. Biol. Pharm. Bull. 21: 93–96.
Metodiewa et al. 1999. Quercetin may act as a cytotoxic prooxidant after its metabolic activation to semiquinone and quinoidal product. Free Radical Biol. Med. 26: 107–116.
Hope it can help...
Thanks to Mr.Jun LU and Fulvio for good papers i will go through it.one small question herbal extract what iam using having prooxidants.i need to prove that by which techniques?.but DPPH assay with herbal compound showing antioxidant nature.Is there any explanation for this?.Thanks in advance.
The data interpretation of DPPH is not trivial. For a discussion, see as an example the paper of Wolf Bors and coworkers, Kinetic study of flavonoid reactions with stable radicals, JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY, 2004, 52, 10, 2816-2820 DOI: 10.1021/jf049880h)
Intracellular ROS data is so good with 2 cell lines when tested with herbal extract .Time depend intracellular ROS increse has been observed.when i use NAC (antioxidant)intracellular ROS dropdown.Now after seeing DPPH data iam confused.
Thanks Seyed for proper explanation.
even i found articles regarding this.some are here.
THE JOURNAL OF BIOLOGICAL CHEMISTRY VOL. 282, NO. 18, pp. 13468–13476, May 4, 2007.
THE JOURNAL OF BIOLOGICAL CHEMISTRY Vol. 280, No. 36, Issue of September 9, pp. 31498–31507, 2005 .
Toxicology in Vitro 26 (2012) 16–23.
from this i came to know Antioxidants can be ROS producers in turn induce apoptosis in cancer cells.
thanks @Alaaeldin ,Phenolic compounds at pH 7.2 oxidant or antioxidants ? as media pH generally 7.2.
Please refer the attached file as an additional information
Article Antioxidative and radioprotective potential of rutin and que...
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