33F-1 |
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Y. V. YUAN1, N. A. Walsh, and M. Carrington. (1) School of Nutrition, Ryerson University, 350 Victoria St., Toronto, ON M5B 2K3, Canada Previously, extracts of the red alga, Palmaria palmata, known as dulse, exhibited hydroxyl and free radical scavenging activities. Laminaria and Porphyra sp. have been reported to reduce the risk of intestinal or mammary cancer in animal studies. An underlying mechanism of these anticarcinogenic effects of seaweeds may involve effects on cell proliferation. The objective of the present study was to characterize the antioxidant and cytotoxic activities of dulse in vitro. The 1-butanol soluble fractions from the methanol extracts of two different grades of dulse (grade 1 and 2) were evaluated for the ability to inhibit lipid oxidation initiated by the azo dyes 2,2'-azo-bis(2-amidinopropane) dihydrochloride (AAPH) and 2,2'-azobis(2,4- dimethylvaleronitrile) (AMVN) in linoleic acid emulsions. The effect of the dulse extracts on cell proliferation was evaluated in a human cervical adenocarcinoma cell culture (HeLa cells). The reducing activity and total polyphenol content of the dulse extracts were also examined in this study. The grade 1 and 2 dulse extracts inhibited (P < 0.05) thiobarbituric acid reactive substances (TBARS) production as a measure of lipid oxidation initiated by the aqueous azo compound, AAPH, in a linoleic acid emulsion. Neither extract influenced TBARS production initiated by the hydrophobic azo compound, AMVN. The dulse extracts had similar polyphenol contents, but the reducing activity of the grade 1 extract < grade 2 extract. After 72 hrs incubation, the grade 1 and 2 dulse extracts inhibited HeLa cell proliferation between 0-78% using 0.5 to 5 mg/mL dulse extract. The dulse extracts inhibited TBARS production initiated by AAPH indicating that the active antioxidant components were hydrophilic in nature. The efficacy of the extracts may have involved reducing activity and polyphenol compounds. The dulse extracts inhibited HeLa cell proliferation suggesting that dulse may also contain anticarcinogenic compounds as demonstrated in this study.
Session 33F, Nutraceuticals & Functional Foods: Antioxidants and phytochemical analysis
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