Kinetics of radical-scavenging activity of hesperetin and hesperidin and their inhibitory activity on COX-2 expression.
Kinetics of radical-scavenging activity of hesperetin and hesperidin and their inhibitory activity on COX-2 expression.
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发表时间：
2005-09
影响因子：
2
通讯作者：
A. Hirata;Y. Murakami;Masao Shoji;Y. Kadoma;S. Fujisawa
中科院分区：
文献类型：
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作者：
A. Hirata;Y. Murakami;Masao Shoji;Y. Kadoma;S. Fujisawa
通过差示扫描量热法（DSC）监测由2，2 '-偶氮二异丁腈（AIBN，一种R* 自由基）或过氧化苯甲酰（BPO，一种PhCOO* 自由基）在70 ℃下在接近厌氧条件下引发的甲基丙烯酸甲酯的聚合，研究黄烷酮橙皮素和橙皮苷的自由基清除活性。它们的化学计量因子测定了抗氧化剂对自由基的抑制速率常数（n）和抑制速率常数与增殖速率常数之比（k（inh）/k（p）），并与trolox进行了比较。（2.0）>橙皮素（0.8）>橙皮苷（0.2），而在BPO体系中，其顺序为橙皮素（0.9）> trolox（0.1）>橙皮苷（0.0）。在AIBN体系中，k（inh）/k（p）值按橙皮苷（195）>橙皮素（33）> trolox（12）的顺序下降，而在BPO体系中，k（inh）/k（p）值按橙皮苷（362）> trolox（127）>橙皮素（18）的顺序下降。对于具有相对小的k（inh）/k（p）值的橙皮素，约1的n值表明作为酚类单体的偶联反应的结果形成二聚体。相反，BPO体系中橙皮苷和trolox的n值<< 1导致非常高的k（inh）/k（p）值。橙皮苷也更能够抑制甲基丙烯酸甲酯自由基的生长，虽然它的n值很小，这表明该化合物也可以抑制多不饱和脂肪酸自由基。在250-500 μ M的浓度范围内，橙皮素和橙皮苷显示出对RAW 264.7细胞中LPS诱导的考克斯-2基因表达的有效抑制，表明这些化合物的抗炎活性。橙皮素和橙皮苷抑制考克斯-2基因表达的能力可能是其抗氧化活性的结果。
The radical-scavenging activities of the flavanones hesperetin and hesperidin were investigated by differential scanning calorimetry (DSC) monitoring of the polymerization of methyl methacrylate initiated by 2,2'-azobisisobutyronitrile (AIBN, an R* radical) or benzoylperoxide (BPO, a PhCOO* radical) at 70 degrees C under nearly anaerobic conditions. Their stoichiometric factor (number of free radicals trapped by one mole of antioxidant moiety (n)) and the ratio of the rate constant of inhibition to that of propagation (k(inh)/k(p)) were determined and compared with that for trolox The n value declined in the order trolox (2.0) > hesperetin (0.8) > hesperidin (0.2) in the AIBN system, whereas it declined in the order hesperetin (0.9) > trolox (0.1) > hesperidin (0.0) in the BPO system. The k(inh)/k(p) value declined in the order hesperidin (195) > hesperetin (33) > trolox (12) in the AIBN system, whereas it declined in the order hesperidin (362) > trolox (127) > hesperetin (18) in the BPO system. The n value of about 1 for hesperetin with a relatively small k(inh)/k(p) value suggests the formation of dimers, as a result of the coupling reaction of phenolic monomers. In contrast, n values << 1 for hesperidin and trolox in the BPO system resulted in very high values for k(inh)/k(p). Hesperidin was also much more able to suppress the growth of methyl methacrylate radicals, although its n value was small, suggesting that this compound may also suppress polyunsaturated fatty acid radicals. In the concentration range 250-500 microM, hesperetin and hesperidin showed potent inhibition of LPS-induced expression of the COX-2 gene in RAW 264.7 cells, suggesting the anti-inflammatory activity of these compounds. The ability of hesperetin and hesperidin to suppress COX-2 gene expression may be a consequence of their antioxidant activity.