Oxidative stress is involved in the pathogenesis of many conditions and is caused by free radicals in concentrations that overwhelm the natural scavenging mechanisms and cause pain and inflammation. This investigation sought to determine whether pain from temporomandibular disorders was associated with increased oxidative stress as measured by biomarkers in saliva and serum. Both salivary and serum levels of the oxidative stress biomarkers including 8-hydroxydeoxyguanosine, malondialdehyde and total antioxidant status were compared in patients with mild and severe TMJD pain and with healthy controls. These biomarkers were determined spectrophotometrically in saliva and serum from 10 high TMJD pain patients, 10 low TMJD pain patients, and 10 healthy control subjects from National Institute of Dental Research's TMJ Implant Registry and Repository. Linear and logistic regression analyses were used to evaluate the association between each biomarker and TMJD pain. The mean levels of log 8-hydroxydeoxyguanosine (saliva P < 0·0001, serum P = 0·0008), malondialdehyde (saliva P = 0·002, serum P = 0·004) and total antioxidant status (saliva P = 0·005; serum P = 0·001) achieved statistically significant differences between groups. In linear regression analysis, both salivary and serum levels of each biomarker were associated with TMJD pain. In a multivariable analysis, again, both salivary levels and serum levels were also different between groups. Salivary levels of oxidative stress ratios of 8-hydroxydeoxyguanosine, malondialdehyde and total antioxidant status were significantly different between patients with TMJD pain and controls and was comparable to that in serum. These biomarkers hold promise as a potential diagnostic and therapeutic strategy.

Freeze-dried water extract of potato peels (pp), containing chlorogenic, caffeic, gallic, and protocatechuic acids, was tested for effectiveness as a natural antioxidant. The pp was prepared from peel waste of Russet Burbank potatoes. Safety concerns regarding the use of pp in foods were investigated. The pp was examined for mutagenic activity using the in vitro Salmonella typhimurium-Escherichia coli microsome assay and found to be nonmutagenic. Plate count of pp revealed <10 CFU/g. The antibacterial activity of the pp was species dependent. It was effective only at high concentration against gram negative and one gram positive bacteria but it was bacteriostatic.

Aqueous extracts of potato peel waste were freeze-dried. High performance liquid chromatography (HPLC) of the freeze-dried extracts revealed that chlorogenic (50.31%), gallic (41.67%), protocatechuic (7.815/o), and caffeic (0.21%) acids were the major phenolics. During 15 days storage of the freeze-dried extract, no degradation of phenolics occurred. After 4 days storage at 63"C, 5.OOg of sunflower oil containing either the freeze-dried extract (200 ppm) or butylated hydroxyanisole (BHA) (200 ppm) reached peroxide values (PV) of 37.38 and 37.47 meq kg-r respectively. L-ascorbic acid-6-palmitate was the best antioxidant (PV= 10.65 meq kg-') but the freeze-dried extract was as good as BHA.

Phenolics were extracted from potato peel waste using water or methanol. Phenolic acids in the extracts were quantified by HPLC. The greatest amounts of phenolic acids resulted when potato homogenate was refluxed with water for 30 min. yielding a total concentration of 48 mg/lOOg. Four phenolic acids (chlorogenic. gallic, protocatechuic, and caffeic) were characterized as major components. Aqueous extracts were stored 20 days and after 7 days at 25'C exposed to light, chlorogenic acid had degraded to caffeic acid.

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