Yu Jun, Wang Limin, Walzem Rosemary L, Miller Edward G, Pike Leonard M, Patil Bhimanagouda S
Texas A&M University-Kingsville Citrus Center, 312 North International Boulevard, Weslaco, Texas 78596, USA.
J Agric Food Chem. 2005 Mar 23;53(6):2009-14. doi: 10.1021/jf0484632.
A variety of in vitro models such as beta-carotene-linoleic acid, 1,1-diphenyl-2-picryl hydrazyl (DPPH), superoxide, and hamster low-density lipoprotein (LDL) were used to measure the antioxidant activity of 11 citrus bioactive compounds. The compounds tested included two limonoids, limonin (Lim) and limonin 17-beta-D-glucopyranoside (LG); eight flavonoids, apigenin (Api), scutellarein (Scu), kaempferol (Kae), rutin trihydrate (Rut), neohesperidin (Neh), neoeriocitrin (Nee), naringenin (Ngn), and naringin(Ng); and a coumarin (bergapten). The above compounds were tested at concentration of 10 microM in all four methods. It was found that Lim, LG, and Ber inhibited <7%, whereas Scu, Kae, and Rut inhibited 51.3%, 47.0%, and 44.4%, respectively, using the beta-carotene-linoleate model system. Lim, LG, Rut, Scu, Nee, and Kae showed 0.5% 0.25%, 32.2%, 18.3%, 17.2%, and 12.2%, respectively, free radical scavenging activity using the DPPH method. In the superoxide model, Lim, LG, and Ber inhibited the production of superoxide radicals by 2.5-10%, while the flavonoids such as Rut, Scu, Nee, and Neh inhibited superoxide formation by 64.1%, 52.1%, 48.3%, and 37.7%, respectively. However, LG did not inhibit LDL oxidation in the hamster LDL model. But, Lim and Ber offered some protection against LDL oxidation, increasing lag time to 345 min (3-fold) and 160 min (33% increase), respectively, while both Rut and Nee increased lag time to 2800 min (23-fold). Scu and Kae increased lag time to 2140 min (18-fold) and 1879 min (15.7-fold), respectively. In general, it seems that flavonoids, which contain a chromanol ring system, had stronger antioxidant activity as compared to limonoids and bergapten, which lack the hydroxy groups. The present study confirmed that several structural features were linked to the strong antioxidant activity of flavonoids. This is the first report on the antioxidant activity of limonin, limonin glucoside, and neoeriocitrin.
使用多种体外模型，如β-胡萝卜素-亚油酸、1,1-二苯基-2-苦基肼（DPPH）、超氧化物和仓鼠低密度脂蛋白（LDL），来测定11种柑橘生物活性化合物的抗氧化活性。所测试的化合物包括两种柠檬苦素，柠檬苦素（Lim）和柠檬苦素17-β-D-葡萄糖苷（LG）；八种黄酮类化合物，芹菜素（Api）、黄芩素（Scu）、山奈酚（Kae）、芦丁三水合物（Rut）、新橙皮苷（Neh）、新 Eriocitrin（Nee）、柚皮素（Ngn）和柚皮苷（Ng）；以及一种香豆素（补骨脂素）。上述化合物在所有四种方法中均以10微摩尔的浓度进行测试。结果发现，使用β-胡萝卜素-亚油酸酯模型系统时，Lim、LG和补骨脂素的抑制率<7%，而Scu、Kae和Rut的抑制率分别为51.3%、47.0%和44.4%。使用DPPH法时，Lim、LG、Rut、Scu、Nee和Kae的自由基清除活性分别为分别为0.5%、0.25%、32.2%、18.3%、17.2%和12.2%。在超氧化物模型中，Lim、LG和补骨脂素抑制超氧自由基的产生2.5%-10%，而Rut、Scu、Nee和Neh等黄酮类化合物分别抑制超氧形成64.1%、52.1%、48.3%和37.7%。然而，LG在仓鼠LDL模型中未抑制LDL氧化。但是，Lim和补骨脂素对LDL氧化有一定保护作用，使延迟时间分别增加到345分钟（3倍）和160分钟（增加33%），而Rut和Nee都将延迟时间增加到2800分钟（23倍）。Scu和Kae分别将延迟时间增加到2140分钟（18倍）和1879分钟（15.7倍）。总体而言，似乎含有色满醇环系统的黄酮类化合物比缺乏羟基的柠檬苦素和补骨脂素具有更强的抗氧化活性。本研究证实了几种结构特征与黄酮类化合物的强抗氧化活性有关。这是关于柠檬苦素、柠檬苦素葡萄糖苷和新 Eriocitrin抗氧化活性的首次报道。
