crocin and 2-2--azobis(2-amidinopropane)

A new AAPH-Incubating HPLC-DAD-HR MS/MS method was developed for the rapid and high-throughput screening of antioxidants directly in natural products and applied to Gardenia jasminoides fruit. This method was assumed that the peak areas of compounds with potential antioxidant activity in HPLC chromatograms would be significantly reduced or disappeared after incubating with the AAPH which can release ROO at physiological conditions (37 °C, pH 7.4). Additionally, the activity of antioxidants can be evaluated by comparing the peak reduction rates and the screened components can be further identified by HRMS/MS. Then, 17 potential natural antioxidants from the crude extract of GJF was screened. Among them, three major components including crocin I, crocin II and crocetin showed excellent ROO scavenging activity, which were further validated by the ORAC assay. In conclusion, our study provided a simple and effective strategy to rapidly screen antioxidants in natural products.

Topics: Antioxidants; Biological Products; Chromatography, High Pressure Liquid; Fruit; Gardenia; Tandem Mass Spectrometry

The authors examined the possible peroxyl radical scavanger effect of some non-steroidal antiinflammatory drugs and isomeric dihidroxy benzoic acids by means of the test based on 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-initiated degradation of crocin. The method is based on spectrophotometric determination of crocin, of which rate of AAPH-initiated degradation can be decreased in the presence of antioxidants with peroxyl radical scavanger activity. The authors studied the crocin degradation-inhibitory effect of phenacetin, paracetamol (acetaminophen), indomethacin, ibuprofen, diclofenac sodium, salicylic acid, salicylamide as well as the 2,3-, 2,4-, 2,5- and 3,4-dihydroxy substituted benzoic acids in 200 microM concentration. In the 60 minute studies the 2,3-, 2,5- and 3,4-dihydroxy benzoic acids proved to show the most effective degradation inhibitory effect. The results draw attention to the different antioxidant activity of salicylic acid and its hydroxylated metabolites (2,3- and 2,5-dihydroxy benzoic acids) formed under physiological conditions.

Topics: Acetaminophen; Amidines; Anti-Inflammatory Agents, Non-Steroidal; Carotenoids; Free Radical Scavengers; Phenacetin; Salicylates

The pro-oxidant activity of potent oxidants and foods was determined using the kinetic analysis of crocin bleaching. In its reduced form, crocin has an absorption band at 443 nm, which disappears upon oxidation by a generic radical species. Hydroxyl radicals generated by hydrogen peroxide, peroxyl radicals from ABAP, and the stable free radical DPPH(*) were allowed to react with crocin in an aqueous solution at 40 degrees C. Pro-oxidant activity was taken as the ratio between the decrease in crocin absorbance at 5 min and the relevant oxidant concentration. The test proposed was used to evaluate the pro-oxidant activity of widely consumed foods such as pasteurized skim milk and bread. They both exerted significant pro-oxidant activities, which were attributed to the early nonenzymatic browning products formed upon heat treatment.

Topics: Amidines; Animals; Bepridil; Biphenyl Compounds; Bread; Carotenoids; Chemical Phenomena; Chemistry, Physical; Food; Hydrogen Peroxide; Hydroxyl Radical; Kinetics; Milk; Oxidants; Oxidation-Reduction; Peroxides; Picrates; Solutions; Water