Absence of mutagenicity of acid pyrogallol-containing hair gels

Pyrogallol induces oxidative stress defects in the fission yeast S. pombe

Apart from the beneficial roles of pyrogallol in industries, it also tends to produce free radicals that trigger apoptosis in human cells. In this study, we checked the toxic effect of pyrogallol in fission yeast S. pombe cells. We observed that the wild type and wat1/pop3 delete cells were unable to grow on plates containing pyrogallol in a dose-dependent manner. Furthermore, the wat1/pop3 delete cells exhibit higher sensitivity against pyrogallol as compared to wild type cells suggesting that the pyrogallol induces oxidative stress. The exposure to pyrogallol also leads to the production of ROS and affects the sporulation in S. pombe.

The Inhibitory Effects of Aqueous Extract from Guava Twigs,Psidium guajavaL., on Mutation and Oxidative Damage

This study examines the inhibitory effects of the aqueous extract from guava twigs (GTE),Psidium guajavaL., on mutation and oxidative damage. The results show that GTE inhibits the mutagenicity of 4-nitroquinoline-N-oxide (4-NQO), a direct mutagen, and 2-aminoanthracene (2-AA), an indirect mutagen, towardSalmonella typhimuriumTA 98 and TA 100. In addition, GTE shows radical scavenging, reducing activities, tyrosinase inhibition, and liposome protection effects. Meanwhile, GTE in the range of 0.1–0.4 mg/mL protects liver cells fromtert-butyl-hydroperoxide-(t-BHP-) induced cytotoxicity. Furthermore, the cytotoxicity inhibition of GTE in thet-BHP-treated cells was demonstrated in a dose-dependent manner. High-performance liquid chromatography analysis suggests that the major phenolic constituents in GTE are gallic acid, ferulic acid, and myricetin. These active phenolic components may contribute to the biological protective effects of GTE in different models. The data suggest that GTE exhibiting biological activities can be applied to antimutation, antityrosinase, and antioxidative damage.

Pyrogallol-associated dermal toxicity and carcinogenicity in F344/N rats and B6C3F1/N mice

Pyrogallol (CAS No. 87-66-1), a benzenetriol used historically as a hair dye and currently in a number of industrial applications, was nominated to the National Toxicology Program (NTP) for testing based on the lack of toxicity and carcinogenicity data. Three-month and two-year toxicity studies to determine the toxicity and carcinogenicity of pyrogallol when applied to naïve skin (i.e. dermal administration) were conducted in both sexes of F344/N rats and B6C3F1/N mice. In the three-month studies, adult rodents were administered pyrogallol in 95% ethanol five days per week for 3 months at doses of up to 150 mg/kg body weight (rats) or 600 mg/kg (mice). Based on the subchronic studies, the doses for the two-year studies in rats and mice were 5, 20 and 75 mg/kg of pyrogallol. All mice and most rats survived until the end of the three-month study and body weights were comparable to controls. During the two-year study, survival of dosed rats and male mice was comparable to controls; however survival of 75 mg/kg female mice significantly decreased compared to controls. The incidences of microscopic non-neoplastic lesions at the site of application were significantly higher in all dosed groups of rats and mice and in both the 3-months and two-year studies. In the two-year study, hyperplasia, hyperkeratosis and inflammation tended to be more severe in mice than in rats, and in the mice they tended to be more severe in females than in males. The incidence of squamous cell carcinoma at the site of application (SOA) in 75 mg/kg female mice and SOA squamous cell papillomas in 75 mg/kg male mice were greater than controls. Pyrogallol was carcinogenic in female mice and may have caused tumors in male mice.

Inhibitory effects of water extract from longan twigs on mutation and nitric oxide production

This study examines the inhibitory effects of water extract from longan twigs (WLTs) on mutation and nitric oxide (NO) production. The results show that WLT inhibited the mutagenicity of 2-aminoanthracene (2-AA), an indirect mutagen, and 4-nitroquinoline-N-oxide (4-NQO), a direct mutagen toward Salmonella typhimurium TA 98 and TA 100. In addition, WLT in the range 0-0.6 mg/ml showed radical scavenging, reducing activities and chelating activity, as well as decreased lipid oxidative damage. Meanwhile, WLT also inhibited tyrosinase activity and NO generation in lipopolysaccharide (LPS) stimulated macrophages. High performance liquid chromatography analysis suggests that the major phenolic constituents in WLT are epicatechin, ellagic acid and gallic acid. These bioactive components may contribute to the protective effects of WLT. Our data suggests that WLT can be applied to antimutation, anti-inflammation and antityrosinase.