Related Experiment Video
Updated: Jul 14, 2026
05:19
Magnetic Resonance Imaging Assessment of Carcinogen-induced Murine Bladder Tumors
Published on: March 29, 2019
Effects of various plant polyphenols on bladder carcinogen benzidine-induced mutagenicity
Patrudu S Makena1, King-Thom Chung
1Department of Biology, The University of Memphis, TN 38152, United States. spmakena@gmail.com
Summary
Plant polyphenols inhibit benzidine-induced mutagenicity and lipid peroxidation. These compounds may act by inhibiting bioactivating enzymes and chelating iron, offering a protective role against oxidative damage.
Area of Science:
- Biochemistry
- Toxicology
- Natural Products Chemistry
Background:
- Benzidine is a known human bladder carcinogen.
- Benzidine induces mutagenicity and lipid peroxidation via oxidative stress.
- Plant polyphenols are investigated for their potential chemopreventive properties.
Purpose of the Study:
- To evaluate the inhibitory effects of various plant polyphenols on benzidine-induced mutagenicity.
- To assess the impact of these polyphenols on benzidine-mediated lipid peroxidation.
- To elucidate the mechanisms underlying the protective effects of plant polyphenols.
Main Methods:
- Ames Salmonella microsome/mutagenicity assay using Salmonella TA102 tester strain.
- Thiobarbituric acid reactive substances (TBARS) assay to measure lipid peroxidation.
- Inclusion of rat liver S9 mix to assess metabolic activation and oxidative stress.
Main Results:
- Several non-mutagenic plant polyphenols strongly inhibited benzidine-induced mutations.
- Plant polyphenols significantly reduced benzidine-mediated and iron-mediated lipid peroxidation in a time-dependent manner.
- Isoliquirtigenin, quercetin dihydrate, and rhein were found to be mutagenic in tester strain TA102.
Conclusions:
- Plant polyphenols exhibit significant inhibitory effects against benzidine's mutagenicity and oxidative damage.
- Inhibition may occur through blocking bioactivating enzymes (cytochrome P-450, peroxidase) and iron chelation.
- These findings highlight the potential of plant polyphenols as protective agents against carcinogen-induced toxicity.
Related Concept Videos
01:25Mutagenicity and Carcinogenicity
Mutagenicity and carcinogenicity refer to the ability of drugs to cause genetic defects and induce cancer, respectively. The International Agency for Research on Cancer (IARC) classifies agents into four groups based on their carcinogenic potential. Group 1 agents are known human carcinogens; group 2A agents are probably carcinogenic to humans; group 3 agents lack data to support their role in carcinogenesis; and group 4 includes agents for which data support that they are not likely to be...
01:30Spontaneous and Induced Mutations
Spontaneous mutations arise infrequently during DNA replication due to errors in the process. A key factor behind these errors is tautomeric shifts in nitrogenous bases, where bases transition from keto to enol forms or amino to imino forms. This shift can alter base-pairing rules, leading to mutations. Additionally, reactive oxygen species (ROS) arising from aerobic metabolism can damage DNA, resulting in depurination (loss of a purine base) or depyrimidination (loss of a pyrimidine base).
01:26Physical Properties of Amines
Amines with low molecular weight are usually gaseous at room temperature, while those with high molecular weight are liquid or solids in nature. Usually, low molecular weight amines have a rotten fish-like smell. Diamines typically have a pungent smell. For instance, cadaverine and putrescine, depicted in Figure 1, are two molecules responsible for decaying tissue.
01:27Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase
Phase II biotransformation reactions are essential for detoxifying and eliminating xenobiotics, including many pharmaceutical compounds. These reactions typically involve conjugation, the covalent attachment of polar endogenous groups such as glucuronic acid, sulfate, methyl, or acetyl moieties to functional groups introduced during Phase I metabolism. The resulting conjugates are more water-soluble, enabling efficient renal or biliary excretion.The major classes of Phase II enzymes include...
01:25Bioactivation and Tissue Toxicity
Bioactivation is a metabolic process that transforms less reactive substances into highly reactive metabolites, initiating tissue toxicity. This transformation can lead to various toxic effects, including carcinogenesis and teratogenesis. Reactive metabolites are classified into two main types: electrophiles and free radicals.Electrophiles are electron-deficient species and are produced primarily by the enzyme cytochrome P-450 during the metabolism of compounds containing carbon, nitrogen, or...
01:11Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Genetic polymorphisms in drug targets have emerged as critical determinants of interindividual variability in drug response and toxicity. Pharmacogenomic investigations increasingly focus on identifying these variations to personalize and optimize therapeutic interventions. A drug target may be a receptor, enzyme, or signaling protein involved in pharmacologic responses or disease-related pathways. While early pharmacogenetic studies focused primarily on drug metabolism, current research...