Study of antioxidant,anti-protease and anti-urease potential of schiff bases of acetophenone with different amines

Summary: seven acetophenone-derived schiff bases were synthesized with different amines including 2-aminobenzoic acid (hl1),4-aminobenzoic acid (hl2),2-naphthylamine (hl3),phenylhydrazine (hl4),1,2-ethanediamine (hl5),1,2-diaminobenzene (hl6) and 1,4- diaminobenzene (hl7),and were subjected to various assays including frap (ferric reducing antioxidant power),dpph (1,1-diphenyl-2-picrylhydrazyl),phosphomolybdate,reducing power,and lipid peroxidation inhibition. they were also evaluated for protease and urease inhibitory activities. based on the results,structure-activity relationship (sar) was determined. only two bases,hl1 and hl4,exhibited antioxidant or free radical scavenging activity in dpph assay. hl4 was most potent (ic50 15 μg/ml),while hl1 was only slightly active. as hl4 was the only base with hydrogen bonded to nitrogen,most probably it involves hydrogen transfer (ht) mechanism. all the bases exhibited a range of antioxidant activity in assays involving electron transfer (et). in the reducing power assay,hl5,hl6 and hl7 showed considerable potential while in frap assay,hl7 was most active followed by hl3. in phosphomolybdate assay,hl6 had the highest potency followed by hl7,while hl4 and hl3 also displayed good activity. all the bases showed moderate to high lipid peroxidation inhibitory activity. hl7 exhibited highest protease inhibitory activity (ec50 43.9 μg/ml) followed by hl6 (ec50 52 μg/ml). hl4 and hl5 did not show protease inhibitory activity at all. hl2 was most potent in inhibiting urease activity ( ec50 29.91 μg/ml). hl5 and hl6 showed moderate activity. the study showed how variation in structures of schiff bases alters their antioxidant and anti-enzymatic activities.