hymecromone and 2-2--azino-di-(3-ethylbenzothiazoline)-6-sulfonic-acid

The antioxidant activity of 4-hydroxycoumarin synthetic derivatives and 4-methylumbelliferone were determined taking 4-hydroxycoumarin as the reference compound. Six 3-aryl-4-hydroxycoumarin derivatives were synthesized from 4-hydroxycoumarin as precursor in order to evaluate changes in their antioxidant properties due to C3-aryl substituent nature. Free radical scavenging capacities of these compounds against two different species DPPH(·) and ABTS(·+) and the protecting ability towards the β-carotene-linoleic acid co-oxidation enzymatically induced by lipoxygenase were measured. In addition, the relationship between the activities of these molecules against DPPH radical and the bond dissociation energy of O-H (BDE) calculated using methods of computational chemistry was evaluated.

Topics: 4-Hydroxycoumarins; Antioxidants; Benzothiazoles; Biphenyl Compounds; Enzyme Inhibitors; Free Radical Scavengers; Lipoxygenase; Oxidation-Reduction; Picrates; Structure-Activity Relationship; Sulfonic Acids; Thermodynamics

Time-resolved fluoroimmunoassay (TR-FIA) and various enzyme immunoassays (EIA) were compared in order to determine the detection system which showed the greatest degree of sensitivity without sacrificing specificity. The system chosen for the evaluation of these assays was the detection of antibodies to human immunodeficiency virus (HIV). For EIA, horseradish peroxidase (HRP) and alkaline phosphatase (AP) were investigated, each with a number of different substrates. HRP with its fluorogenic substrate, 3-(p-hydroxyphenyl)propionic acid (HPPA) was 1.6 times (p less than 0.01) more sensitive than with 3,3',5,5'-tetramethylbenzidine (TMB) and four times (p less than 0.001) more sensitive than with 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS). AP with its fluorogenic substrate, 4-methylumbelliferyl phosphate (4MeUP), was 6-7 times (p less than 0.001) more sensitive than with phenolphthalein monophosphate (PMP) and 8-13 times (p less than 0.001) more sensitive than with p-nitrophenyl phosphate (pNPP). TR-FIA with Eu3(+)-labelled anti-human IgG was equivalent in sensitivity to HRP with TMB and AP with 4MeUP.

Topics: Acquired Immunodeficiency Syndrome; Alkaline Phosphatase; Aniline Compounds; Benzidines; Benzothiazoles; Chromogenic Compounds; Fluoroimmunoassay; HIV; Horseradish Peroxidase; Humans; Hymecromone; Immunoenzyme Techniques; Organophosphorus Compounds; Phenolphthaleins; Phenylpropionates; Sensitivity and Specificity; Sulfonic Acids

The mutagenic action of six compounds used in ELISA, EMIT and EIA assays, was investigated by means of the fluctuation test, with Klebsiella pneumoniae as a test organism, and the Ames' plate incorporation test using Salmonella typhimurium TA 98, TA 100 and TA 1537. It appears that 2,2'-azino-di(3-ethyl-benzthiazoline sulphonic acid (6)) or ABTS exerts mutagenic action on Klebsiella pneumoniae at a concentration of 11 g/l, on Salmonella typhimurium TA 100 at a top agar concentration of 0.1 g/l, on Salmonella typhimurium TA 98 at 0.2 g/l and on Salmonella typhimurium TA 1537 at 10 g/l. With umbelliferone, mutagenic action was found only with Klebsiella pneumoniae at a concentration of 0.8 g/l or higher. With o-phenylenediamine, strong mutagenic activity was found only with strain TA 98 and metabolic activation at a top agar concentration of 0.001 g/l. With 5-aminosalicylic acid, beta-methylumbelliferone and p-nitrophenyl-phosphate, no mutagenic action was observed.

Topics: Aminosalicylic Acids; Benzothiazoles; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Hymecromone; Immunoenzyme Techniques; Klebsiella pneumoniae; Mutagenicity Tests; Mutagens; Phenylenediamines; Salmonella typhimurium; Sulfonic Acids; Umbelliferones