Synthesis, Characterization and Antioxidant Activity of 4-Hydroxychalcone Derived Schiff Base

Chiang, Kuan Lin (2025) Synthesis, Characterization and Antioxidant Activity of 4-Hydroxychalcone Derived Schiff Base. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

A novel Schiff base of (E)-2(4-hydroxybenzylidene)-N-methylhydrazine-1-carbothioamide (4-OHB-MHCT) was successfully synthesized from 4-hydroxybenzaldehyde (4-OHBenz) and 4-methyl-3-thiosemicarbazide (4-M-3-TSC) via acid-catalyzed condensation reaction. The synthesized compound was characterized using different physicochemical and spectroscopic analysis, such as ATR-FTIR, DSC, UV-Vis, and HPLC-MS. The antioxidant activities of the compound were determined by using both 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging and Ferric Reducing Antioxidant Power (FRAP) assays. The compound predominantly existed as thione tautomer in solid. The IC₅₀ of compound, 4-OHB-MHCT : 8.59 ± 2.06 μM, IC₅₀ value of AA : 7.50 ± 3.79 μM while FRAP value of 4-OHB-MHCT : 42.17 ± 0.10 mMol Fe²⁺ /g , FRAP value of AA : 12.76 ± 0.10 mMol Fe²⁺ /g. The AEAC of IC₅₀ value obtained was 8.43 x 104 mg ascorbic acid / 100 g sample, showing a high level of antioxidant activity. Although 4-OHB-MHCT has a higher IC₅₀ value than AA, however it shows a higher potency in antioxidant activity when compared to the raw materials in both DPPH & FRAP analysis due to it exhibits the lowest IC₅₀ value & shows the highest FRAP value as compared to the raw materials, and the FRAP value of 4-OHB-MHTC is greater than AA.