Abstract: Compoundswith two phenolic OH groups like curcumin possess efficient antioxidant and anti-inflammatory activity. We synthesized p-cresol dimer (2,2'-dihydroxy-5,5'-dimethylbiphenol, 2a) and p-methoxyphenol dimer (2,2'-dihydroxy-5,5'-dimethoxybiphenol, 2b) by ortho-ortho coupling reactions of the parent monomers, p-cresol (1a) and p-methoxyphenol (1b), respectively. Their antioxidant activity was determined using the induction period method, and their cytotoxicity towards RAW 264.7 cells was also investigated using a cell counting kit. The stoichiometric factors n (number of free radicals trapped by one mole of antioxidant moiety) for 2a and 2b were 3 and 2.8, respectively, being greater than those for 1a and 1b. The ratio of the rate constant of inhibition to that of propagation (kinh/kp) for 2a and 2b was similar to that for 2-t-butyl-4-methoxyphenol (BHA), a conventional food antioxidant. The 50% inhibitory dose (ID50) declined in the order 1b > 1a >> 2b > 2a > BHA. The cytotoxicity for 2a and 2b was significantly greater than that for the parent monomers (p < 0.001), but smaller than that for BHA (p < 0.01). Compounds 2a and 2b may be useful as food antioxidants.
Keywords: p-cresol dimer; p-methoxyphenol dimer; antioxidant; cytotoxicity
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Kadoma, Y.; Murakami, Y.; Ogiwara, T.; Machino, M.; Yokoe, I.; Fujisawa, S. Radical-Scavenging Activity and Cytotoxicity of p-Methoxyphenol and p-Cresol Dimers. Molecules 2010, 15, 1103-1112.
Kadoma Y, Murakami Y, Ogiwara T, Machino M, Yokoe I, Fujisawa S. Radical-Scavenging Activity and Cytotoxicity of p-Methoxyphenol and p-Cresol Dimers. Molecules. 2010; 15(3):1103-1112.
Kadoma, Yoshinori; Murakami, Yukio; Ogiwara, Takako; Machino, Mamoru; Yokoe, Ichiro; Fujisawa, Seiichiro. 2010. "Radical-Scavenging Activity and Cytotoxicity of p-Methoxyphenol and p-Cresol Dimers." Molecules 15, no. 3: 1103-1112.