Antiphotooxidative Effect of Ascorbic Acid Microemulsion in Virgin Coconut Oil

This study was intended to determine the effectiveness of ascorbic acid microemulsion for inhibiting photooxidation of virgin coconut oil （VCO）. The ascorbic acid microemulsion was prepared by mixing ascorbic acid, deionized water, surfactant mixture, and VCO as continuous phase. Ascorbic acid microemulsion at 50, 100, 150, 200, or 250 ppm was dispersed into VCO. The same level of ascorbyl palmitate, TBHQ （tertiary butylhydroquinone）, and BHA （butylated hidroxyanisole） were added into VCO and used for comparison. All of these samples were subsequently subjected to photooxidation under fluorescent light exposure （4,000 lux） for up to 8 hours at room temperature （30 ~ 1 ~C）. Peroxide values and p-anisidine values of photooxidized samples were measured at 1 hour interval. The result indicated that at the level of 250 ppm, ascorbic acid which was included into the microemulsion system effectively inhibited photooxidation of VCO in comparison with the other antioxidants. This study confirmed that a highly hydrophilic singlet oxygen quencher （SOQ） such as ascorbic acid can be successfully incorporated into the microemulsion system and the addition of ascorbic acid microemulsion effectively inhibited photooxidation of VCO during storage under fluorescent light.

Upregulation of Nrf2-regulated gene expression by tBHQ alleviates cyclophosphamide-induced hematotoxicity in mice

Hematological toxicity （bone marrow suppression） is the most common dose-limiting adverse effect of chemotherapies. The nuclear factor erythroid 2-related factor 2 （Nrf2） is a pivotal coordinator of cellular defensive responses against chemical insults in many tissues including bone marrow. In the present study, the effects of tert-butylhydroquinone （tBHQ） on the expression of Nrf2-regulated genes in peripheral blood cells and cyclophosphamide （CTX）-induced hematotoxicity in mice were investigated. CTX induced apoptosis of peripheral blood nucleated cells and leukopenia in mice, accompanied by mobilization of bone marrow hematopoietic cells, tBHQ treatment induced the expression of Nrf2-regulated genes such as heine oxygenase 1 （HO1） and glutamate-cysteine ligase catalytic subtmit （GCLC） in RAW264.7 mouse macrophage cells and peripheral blood cells both in vitro and in vivo. Interestingly, pretreatment with tBHQ alleviated CTX-induced mouse peripheral blood cell apoptosis and leukopenia in vivo, indicating possible involvement of Nrf2 in the protection against CTX-induced hematotoxicity. This study provides new information on the chemotherapy-induced hematotoxicity, and suggests Nrf2 could serve as a target for the development of chemoprotectants against hematotoxicity.

Chemometrics-assisted excitation-emission fluorescence spectroscopy for simultaneous determination of ethoxyquin and tert-butylhydroquinone in biological fluid samples

A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix （EEM） fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin （EQ） and tert-butylhydroquinone （TBHQ） contents in biological fluid samples was developed. After a simple data preprocessing that was to insert zeros below the first-order Rayleigh scattering, the second-order calibration method based on the alternating normalization-weighed error （ANWE） algorithm was used to deal with EEM data. Via the introduced ＂second-order advantage＂, the individual con- centrations of the analytes of interest could be obtained even in the presence of uncalibrated interferences. The experimental concentration ranges for the analytes were as follows： EQ, from 4.58 to 20.6 p.g mL-1 in plasma and from 6.87 to 20.6 gg mL-1 in urine; TBHQ, from 4.49 to 20.2 ~tg mL-1 in plasma and from 6.73 to 22.4 I.tg mL-l in urine. The recoveries from spiked bi- ological fluid samples were in the ranges of 92.8%-106.2% for EQ and 94.6%-107.2% for TBHQ. These results demonstrate that the three-dimensional EEM fluorescence with second-order calibration method is a powerful tool for obtaining both EQ and TBHQ quantitative results in plasma and urine samples, and could be applied to more complex matrices.