Synthesis of Novel 5-Aminosalicylic Acid Schiff Bases by Grinding Method: Evaluation for in Vitro Antioxidant and Antibacterial Activities

Abstract

Grinding technique as a method employing green chemistry was selected for the synthesis of Schiff bases from 5-aminosalicylic acid and substituted benzaldehydes. Two known and eight novel 5-aminosalicylic acid Schiff bases were synthesized and recrystallized using methanol. All the compounds were characterized by their physical data and spectral studies such as IR, 1 H NMR, 13 C NMR and Mass. The synthesized compounds were evaluated for in vitro antioxidant activity by scavenging 1,1-diphenyl-2picrylhydrazyl (DPPH) and nitric oxide free radicals at 100μM concentration. The activity data revealed that the compounds with 4-hydroxy-3,5-dimethoxy substitution and 3,4-methylenedioxy substitution on N-benzylidene ring showed highest antioxidant activity in DPPH and nitric oxide scavenging models respectively. The activity of these compounds was found to be greater than 5-aminosalicylic acid and the standards employed. All the compounds were evaluated for antibacterial activity by agar well diffusion method using gram negative and gram positive bacteria such as E. coli, P. aeruginosa, S. aureus and B. subtilis. The results indicate that the evaluated compounds showed good to moderate antibacterial activity.

Metal Complex

“…These Schiff bases form a new family of compounds with promising antibacterial and anticancer properties. Schiff base metal complexes, which are derived from halogenated salicylaldehyde, have a broad variety of applications in research involving biocatalytic, anti-HIV, antibacterial, and luminous probes for DNA and RNA breakage reactions [23][24][25]. These derivatized complexes are also employed as fungicides, insecticides, and flavoring agents for bouquets and liquor [26][27][28][29][30][31][32].…”

Synthesis, characterization, and biological activity assessment of new metal complexes of Schiff bases produced from benzoin

“…Schiff bases are considered one of the most important organic compounds that are easy to prepare and of wide importance because they possess important medicinal properties as substances with high efficacy against bacteria, fungi, and anti-tumors, which increases the effectiveness of these compounds, and their consistency with transition metals that have high effectiveness in increasing the immunity of living cells, such as zinc, manganese, and silver [1] Schiff base compounds are known to be prepared by a condensation reaction between amine and carbonyl compounds such as aldehydes and ketones, which produces a compound with a functional group called the azomethine which is considered a very effective group in terms of pharmacology. In addition to their consistency with metal atoms through the donation of the double electron to the nitrogen atom, where they are stable complexes with important therapeutic properties in the preparation of many anti-inflammatory drugs [2]. Web Site: www.kjps.isnra.org E-mail: kjps@uoalkitab.edu.iq 29 Chemical sciences are currently heading towards the preparation of more drugs, antibiotics, and anti-cancer drugs that can be said to be new drugs or drugs developed from existing ones to help humans combat stubborn germs that are beginning to show resistance to traditional drugs used at the present time.…”