Effect of antioxidants on radical intensity and cytotoxic activity of eugenol.
The effect of antioxidants on the radical intensity of 2-methoxy-4-(2-propenyl)phenol (eugenol) was investigated, using ESR spectroscopy. Eugenol produced radicals in alkaline solutions, with an optimum pH of 9.5. The intensity of eugenol radical was a positive function of its concentration, reaching a plateau level at 100 mM. The eugenol radical was rapidly diminished under alkaline conditions. Water-soluble antioxidants, such as cysteine, N-acetyl-L-cysteine, glutathione and sodium ascorbate, completely scavenged the eugenol radical. Gallic acid at lower doses significantly, but not completely, scavenged the eugenol radical. Among water-insoluble antioxidants, terpenes (beta-carotene, retinol, lycopene) effectively scavenged the eugenol radical, whereas phenolic compounds (alpha-tocopherol, Trolox) were inactive. Millimolar concentrations of eugenol were cytotoxic against human salivary gland and oral squamous carcinoma cell lines. Addition of sodium ascorbate or beta-carotene reproducibly reduced the cytotoxic activity of eugenol. The applicability of the antioxidants in dentistry was discussed.
Analysis Center, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
K
K
Satoh
Y
Y
Ida
H
H
Sakagami
T
T
Tanaka
S
S
Fujisawa
D000111:Acetylcysteine / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell; D002338:Carotenoids / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects*; D002839:Chromans / Q000494:pharmacology; D003545:Cysteine / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D005054:Eugenol / Q000737:chemistry* / Q000633:toxicity*; D005609:Free Radicals; D005707:Gallic Acid / Q000494:pharmacology; D005978:Glutathione / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D000077276:Lycopene; D009062:Mouth Neoplasms; D012468:Salivary Gland Neoplasms; D014407:Tumor Cells, Cultured; D014801:Vitamin A / Q000494:pharmacology; D014810:Vitamin E / Q000494:pharmacology; D014815:Vitamins / Q000494:pharmacology*; D019207:beta Carotene / Q000494:pharmacology
D000975:Antioxidants; D002839:Chromans; D005609:Free Radicals; D014815:Vitamins; D019207:beta Carotene; D014801:Vitamin A; D014810:Vitamin E; D002338:Carotenoids; D005054:Eugenol; D005707:Gallic Acid; D005978:Glutathione; D003545:Cysteine; D001205:Ascorbic Acid; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; D000077276:Lycopene; D000111:Acetylcysteine