ascorbic-acid and 1-3-4-thiadiazole

The initial steps in preclinical drug developing research concern the synthesis of new compounds for specific therapeutic use which needs to be confirmed by in vitro and then in vivo testing. Nine thiazolidinone derivatives (numerically labeled 1-9) classified as follows: 1,3-thiazole-based compounds (1 and 2); 1,3,4-thiadiazole based compounds (3 and 4); substituted 5-benzylideno-2-adamantylthiazol[3,2-b][1,2,4]triazol-6(5H)ones (5-8); and an ethylaminothiazole-based chalcone (9), were tested for antioxidant activity (AOA) by using three in vitro assays: DPPH (1,1-diphenyl-2-picrylhydrazyl scavenging capacity test); FRAP (ferric reducing antioxidant power test); and TBARS (thiobarbituric acid reactive substances test). Compounds 1-4 and 9 in particular are newly synthesized compounds. Also, traditional antioxidants Vitamins E and C and α-lipoic acid (α-LA) were tested. The results of DPPH testing: Vitamin C 94.35%, Vitamin E 2.99% and α-LA 1.57%; compounds: 4 33.98%; 2 18.73%; 1 15.62%; 5 6.59%; 3 4.99%; 6-9 demonstrated almost no AOA. The results of TBARS testing (% of LPO inhibition): Vitamin C 62.32%; Vitamin E 36.29%; α-LA 51.36%; compounds: 1 62.11%; 5 66.71%; 9 60.93%; 4, 6 and 7 demonstrated ∼50%; 3 and 8 displayed ∼38%; 2 23.51%. By FRAP method, Vitamins E and C showed equal AOA, ∼100%, unlike α-LA (no AOA), and AOA of the tested compounds (expressed as a fraction of the AOA of Vitamin C) were: 2 and 4-75%; 8, 3 and 1-45%; 5-7 and 9-27%. Different red-ox reaction principles between these assays dictate different AOA outcomes for a single compound. Vitamin C appeared to be the superior antioxidant out of the traditional antioxidants; and compound 4 was superior to other tested thiazolidinone derivatives. Vitamin C appeared to be the superior antioxidant out of the traditional antioxidants; and compound 4 was superior to other tested thiazolidinone derivatives. Phenyl-functionalized benzylidene, amino-carbonyl functional domains and chelating ligand properties of the thiazolidinone derivatives correlated with AOA.

Topics: Antioxidants; Ascorbic Acid; Biphenyl Compounds; Oxidation-Reduction; Picrates; Thiadiazoles; Thiazoles; Thiobarbituric Acid Reactive Substances; Thioctic Acid; Vitamin E

Two 2-amino-1,3,4-thiadiazoles containing phenolic hydroxyl groups were combined with different carboxylic acid chlorides giving sixteen amide derivatives with good antioxidant and antiproliferative potential. The compound 3'c with an adamantane ring displayed excellent DPPH radical scavenging activity and good cytotoxic activity against human acute promyelocytic leukemia HL-60 cells, while 1,3,4-thiadiazole 3'h with 4-chlorophenyl moiety was found to be the most effective in inhibition of survival of lung carcinoma A549 cells. All examined thiadiazoles except 3a and 3'a exerted higher cytotoxic activities on A549 and HL-60 cancer cells when compared with normal fibroblasts MRC-5, pointing to selectivity in their antiproliferative action. Some of the most active novel compounds 3c, 3'c, 3'g and 3'h induced significant increase in the percentage of HL-60 cells in the subG1 cell cycle phase in comparison with the control cells. The induction of cell death in HL-60 cells by these compounds was at least partially dependent on activation of caspase-3 and caspase-8. The compounds 3c and 3'c exerted strong antiangiogenic activity. Furthermore, compounds 3c, 3'c, 3'g and 3'h showed the ability to down-regulate the MMP2 and VEGFA expression levels in the treated HL-60 cells when compared with the control cell samples.

Topics: A549 Cells; Angiogenesis Inhibitors; Antioxidants; Caspase 3; Caspase 8; Cell Line; Cell Proliferation; Cell Survival; Down-Regulation; G1 Phase Cell Cycle Checkpoints; HL-60 Cells; Humans; Hydroxybenzoates; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Structure-Activity Relationship; Thiadiazoles; Vascular Endothelial Growth Factor A

A new class of oxadiazoles is prepared by treating aminosulfonylacetic acids with different carboxylic acid hydrazides. Interconversion of oxadiazoles to thiadiazoles is carried out with thiourea. The compounds are screened for antimicrobial and antioxidant activities.

Topics: Anti-Infective Agents; Antioxidants; Bacteria; Biphenyl Compounds; Microbial Sensitivity Tests; Nitric Oxide; Oxadiazoles; Picrates; Thiadiazoles