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Updated: May 12, 2026

Valorization of the Red Seaweed Gracilaria gracilis Through a Biorefinery Approach
Published on: November 21, 2023
Radical scavenging and singlet oxygen quenching activity of extracts from Indian seaweeds
N M Sachindra1, M K W A Airanthi, M Hosokawa
1Faculty of Fisheries, Hokkaido University, 3-1-1 Minato, Hakodate, 041-8611 Japan ; Central Food Technological Research Institute (Council of Scientific and Industrial Research), Mysore, 570 020 India.
Abstract:
Free radicals and singlet oxygen are responsible for oxidative stress related diseases and many natural compounds are known to have antioxidant properties. In this study, extracts from brown and red seaweeds of Indian origin were evaluated for their ability to scavenge different radicals and quench singlet oxygen. The crude extract in methanol and its fractions in different solvents were evaluated for their activity. The methanol extract and its fractions from brown seaweed exhibited higher 2,2'-azinobis(3-ethylbenzothizoline-6-sulfonic acid) radical scavenging activity with more than 90% scavenging in butanol and ethyl acetate fractions and correlated with polyphenol content. There was a significant difference (p≤0.001) in hydroxyl radical scavenging activity between different fractions of the same seaweed. Among the crude extracts, extract from Gracilaria corticata showed the highest (14.0%) activity. Crude extract from brown seaweeds showed higher peroxyl radical scavenging activity compared to red seaweeds. In fractions from brown seaweed extracts, highest activity was observed in ethyl acetate fraction (>88%) followed by hexane fraction (>40 %). Ethyl acetate fraction from crude extract showed higher inhibitory activity against hemoglobin induced linoleic acid oxidation. Singlet oxygen quenching activity of the crude extract from brown seaweed was lower (<13%) compared to red seaweeds (16.4-20.5%).
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