Vol. 1 Issue 1, pp: (1-16), March 2016.
Article Number: PRJA45923613
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1Department of Chemical Technology, University of Calcutta, Kolkata, West Bengal 700 009, India.
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This article has been retracted at the request of the publisher. A Chemist noticed an error which was communicated to the corresponding author and the editors of the journal. The manuscript was then re-assigned to three external reviewers. Here are some of their comments:
Apologies are offered to readers and the entire scientific community that these errors were not detected during peer review period.
α-lipoic acid was isolated from de-oiled rice bran by solvent extraction, followed by purification. α-lipoic acid was isolated using ten different solvents/solvent mixtures. A 1:10 proportion of de-oiled bran and solvents/solvent mixture was maintained. The mixtures were intensely blended followed by ultrasonication. Finally, they were purified by protein removal and treatment with alkali. The most effective solvent system for maximum yield of α-lipoic acid was water:ethanol (2:1) which yielded an amount of (0.43+0.02)% α-lipoic acid. Identity of the isolated and purified product was confirmed by HPLC, FTIR, NMR and GC analysis methods. HPLC retention time at 2.96 minutes and GC retention time at 19.80 minutes were obtained which were similar to those of the procured standard α-lipoic acid. FTIR and NMR techniques confirmed the atypical S–S linkage of α-lipoic acid, its carboxylic acid group and the ring structure. Finally varying concentrations of α-lipoic acid were prepared in water and their antioxidant efficacy were analysed by virtue of seven in vitro assay entities. A positive outcome was observed with α-lipoic acid in response to all the antioxidant assays performed. A concentration of 0.1% α-lipoic acid indicated to be the most effective one in terms of providing maximum antioxidant potency.Key words: α-lipoic acid; antioxidant; isolation; purification; rice bran; solvent extraction.