Antioxidant activity screening of a series of synthesized 2-aryl thiazolidine-4- carboxylic acids

Antioxidants play an important role in inhibiting and scavenging radicals, thus providing protection to humans against infections and degenerative diseases. The present article focuses on the synthesis and antioxidant activity studies of a variety of 2-aryl thiazolidine -4-carboxylic acids. A series of twenty fully characterized 2-aryl thiazolidine-4-carboxylic acids have been synthesized by nucleophilic cyclization of L-Cysteine hydrochloride with aromatic aldehydes including some novel moieties. The series is screened for their total antioxidant activity, Nitric oxide, DPPH radical scavenging activity and are also studied for kinetic studies on ABTS radical scavenging. We observed that, the aromatic substituent at position 2 in thiazolidine ring influences the antioxidant potential of the moiety. The nature of the substituent and their position on aromatic ring has been correlated with observed antioxidant activity. Though, CH3 group on aromatic ring shows better radical scavenging property than other groups like Cl, Br, OCH3 , N(CH3), NO2, COOH; the presence of phenolic OH on aromatic ring has demonstrated a vital role in enhancing radical scavenging activity. The diphenolic aromatic substituents have exhibited merely equivalent antioxidant properties in comparison with ascorbic acid.