Synthesis and antioxidant activity evaluations of melatonin-based analogue indole-hydrazide/hydrazone derivatives

Figures & data

Figure 1.  Modifications made on MLT molecule.

Table 1.  Antioxidant activity results of synthesized compounds.

Compounds^a	Superoxide radical inhibition (%)		DPPH scavenging activity	LP (% inhibition)
	1 mM	0.1 mM	IC50 µM	0.1 mM
1a	64 ± 3.0	P	42 ± 2	20.68 ± 0.55
1b	P	P	60 ± 2	31.03 ± 0.71
1c	P	P	60 ± 1	34.48 ± 0.36
1d	39 ± 7.5	P	19 ± 2	37.93 ± 0.25
1e	7.0 ± 1.5	P	21 ± 1	37.93 ± 0.33
1f	NA	NA	55 ± 4	20.68 ± 0.44
1g	P	P	22 ± 3	41.38 ± 0.29
1h	93 ± 2.4	P	20 ± 2	44.83 ± 0.36
1i	45 ± 2.0	NA	22 ± 1	41.37 ± 0.28
1j	79 ± 2.5	NA	2 ± 0.4	51.72 ± 0.22
1k	88 ± 4.8	P	24 ± 2	37.93 ± 0.12
1l	46 ± 1.7	P	23 ± 1	41.37 ± 0.19
1m	93 ± 3.0	P	15 ± 2	37.93 ± 0.84
1n	91 ± 2.0	P	28 ± 1	27.58 ± 0.29
1o	89 ± 5.2	NA	20 ± 4	27.58 ± 0.52
1p	95 ± 1.0	NA	20 ± 2	31.03 ± 0.55
1r	86 ± 4.5	P	30 ± 5	31.03 ± 0.61
1s	81 ± 5.7	P	19 ± 3	34.48 ± 0.54
1t	88 ± 3.5	P	24 ± 1	34.48 ± 0.32
1u	P	P	650 ± 19	44.82 ± 0.54
1v	P	25 ± 1.2	—	27.58 ± 0.60
1y	P	NA	—	41.38 ± 0.56
Melatonin	80 ± 1.5	20 ± 1.4	780 ± 25	46 ± 1.4
BHT	—	—	15 ± 2	-

P= prooxidant, NA = no activity.

^aCompounds were diluted with DMSO (solvent showed no antioxidant activity).

Figure 2.  Synthetic pathway of melatonin analogues.