Inhibition of phthalocyanine-sensitized photohemolysis of human erythrocytes by polyphenolic antioxidants: description of quantitative structure–activity relationships

• Published in: Cancer letters 2000-08, Vol.157 (1), p.39-44
• Main Authors: MAROZIENE, A, KLIUKIENE, R, SARLAUSKAS, J, CENAS, N
• Format: Article
• Language: English
• Subjects: Antioxidant; Antioxidants - pharmacology; Biological and medical sciences; Dose-Response Relationship, Drug; Drug Interactions; Drug toxicity and drugs side effects treatment; Erythrocytes; Erythrocytes - drug effects; Erythrocytes - radiation effects; Flavonoids - pharmacology; Hemolysis - drug effects; Hemolysis - radiation effects; Humans; Indoles - antagonists & inhibitors; Indoles - pharmacology; Kinetics; Medical sciences; Organometallic Compounds - antagonists & inhibitors; Organometallic Compounds - pharmacology; Pharmacology. Drug treatments; Phenols - pharmacology; Photobiology; Photosensitization; Polymers - pharmacology; Polyphenol; Radiation-Sensitizing Agents - pharmacology; Reactive Oxygen Species - metabolism; Singlet oxygen; Structure-Activity Relationship; Toxicity: cardiovascular system
• ISSN: 0304-3835; 1872-7980
• DOI: 10.1016/S0304-3835(00)00469-9

Polyphenolic antioxidants protected against Al-phthalocyanine tetrasulfonate-sensitized photohemolysis of human erythrocytes. A quantitative structure–activity relationship has been obtained to describe the protective effects of di- and trihydroxybenzenes: log cI 50 (μM)=(1.8620±1.5565)+(3.6366±2.8245) E 1 7 (V)−(0.4034±0.0765) log P ( r 2=0.8367), where cI 50 represents the concentrations of compounds for the 2-fold increase in the lag-phase of hemolysis, E 1 7 represents the compound single-electron oxidation potential, and P represents the octanol/water partition coefficient. The cI 50 for quercetin and taxifolin were close, and cI 50 for morin, kaempferol and hesperetin were lower than might be predicted by this equation. The protection from hemolysis by azide, a quencher of singlet oxygen ( 1O 2) was accompanied by increase in cI 50 of polyphenols, indicating that azide and polyphenols competed for the same damaging species, 1O 2. These findings point out to two factors, determining the protective efficiency of polyphenols against 1O 2, namely, ease of electron donation and lipophilicity.