Kim Young-Hee, Bang Chae-Young, Won Eun-Kyung, Kim Jong-Pyung, Choung Se-Young
Department of Hygienic Chemistry and Kyung Hee East-West Pharmaceutical Research Institute, College of Pharmacy, Kyung Hee University, Seoul, Korea.
J Med Food. 2009 Aug;12(4):885-92. doi: 10.1089/jmf.2008.1127.
Vaccinium uliginosum L. (also known as bog bilberry) is a low-growing deciduous shrub classified in the Ericaceae family of plants, which includes numerous Vaccinium berries, blueberries, and cranberries. Berries of the Ericaceae family are known to contain organic acids, vitamins, glycosides, and anthocyanins and have been reported to have antioxidant activity. In order to identify the antioxidative principles of V. uliginosum, we separated water extracts into polyphenol, anthocyanin-rich (pigment), and sugar/acid fractions by using ethyl acetate, acidic methanol (MeOH), and 0.01 N HCl. Antioxidant activities were assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide radical, and hydroxyl radical assays. The crude extract and fractions containing polyphenol and pigment exhibited the greatest antioxidant activities with 50% inhibitory concentration (IC(50)) values of 85.8 microg/mL, 33.2 microg/mL, and 16.7 microg/mL, respectively, for the DPPH assay and 48.1 microg/mL, 83.8 microg/mL, and 51.9 microg/mL for the nonenzymatic superoxide radical assay. The fractions containing polyphenol, pigment, and sugar/acid significantly inhibited xanthine oxidase. To investigate the functional compounds from the active fractions, we purified the polyphenol fraction and separated the compounds by using chromatographic techniques. The crude extract was dissolved in MeOH and further purified by reversed-phase high-performance liquid chromatography (HPLC) using MeOH-water (35:65 vol/vol) (with 0.04% trifluoroacetic acid) to obtain VU-EA-1 (16.6 mg), VU-EA-2 (8.5 mg), VU-EA-3 (19.8 mg), VU-EA-4 (12.8 mg), VU-EA-5 (6.5 mg), and VU-EA-6 (23.5 mg). The MeOH-washed fraction from the HPLC was concentrated and purified by reversed-phase HPLC using MeOH-water (50:50 vol/vol) to give VU-EA-10 (12.4 mg). Antioxidant activity was assessed by DPPH, superoxide radical, and hydroxyl radical assays. The isolated compounds exhibited dose-dependent antioxidant activity with IC(50) values of 7.6 microg/mL (VU-EA-10) for the DPPH assay, 67.8 microg/mL (VU-EA-4) for the nonenzymatic superoxide radical assay, and 3.7 microg/mL (VU-EA-10) and 7.6 microg/ml (VU-EA-6) for the enzymatic superoxide radical assay and 30% inhibitory concentration values of 0.58 microg/mL (VU-EA-1), 0.57 microg/mL (VU-EA-5), and 0.70 microg/mL (VU-EA-6) for the hydroxyl radical assay. In conclusion, V. uliginosum had potent antioxidative activity, and flavonoids were isolated as the main active principles.
笃斯越桔（也称为沼泽蓝莓）是一种低矮的落叶灌木，属于杜鹃花科植物，该科包括众多越桔属浆果、蓝莓和蔓越莓。已知杜鹃花科的浆果含有有机酸、维生素、糖苷和花青素，并且据报道具有抗氧化活性。为了确定笃斯越桔的抗氧化成分，我们使用乙酸乙酯、酸性甲醇（MeOH）和0.01 N盐酸将水提取物分离为多酚、富含花青素（色素）和糖/酸部分。通过2,2-二苯基-1-苦基肼（DPPH）、超氧自由基和羟基自由基测定来评估抗氧化活性。粗提取物以及含有多酚和色素的部分表现出最大的抗氧化活性，对于DPPH测定，其50%抑制浓度（IC50）值分别为85.8 μg/mL、33.2 μg/mL和16.7 μg/mL，对于非酶促超氧自由基测定，其IC50值分别为48.1 μg/mL、83.8 μg/mL和51.9 μg/mL。含有多酚、色素和糖/酸的部分显著抑制黄嘌呤氧化酶。为了研究活性部分中的功能化合物，我们纯化了多酚部分并使用色谱技术分离化合物。将粗提取物溶解在甲醇中，并使用甲醇-水（35:65体积/体积）（含0.04%三氟乙酸）通过反相高效液相色谱（HPLC）进一步纯化，得到VU-EA-1（16.6 mg）、VU-EA-2（8.5 mg）、VU-EA-3（19.8 mg）、VU-EA-4（12.8 mg）、VU-EA-5（6.5 mg）和VU-EA-6（23.5 mg）。将HPLC的甲醇洗脱部分浓缩并使用甲醇-水（50:50体积/体积）通过反相HPLC纯化，得到VU-EA-10（12.4 mg）。通过DPPH、超氧自由基和羟基自由基测定来评估抗氧化活性。分离出的化合物表现出剂量依赖性抗氧化活性，对于DPPH测定，IC50值为7.6 μg/mL（VU-EA-10），对于非酶促超氧自由基测定，IC50值为67.8 μg/mL（VU-EA-4），对于酶促超氧自由基测定，IC50值为3.7 μg/mL（VU-EA-10）和7.6 μg/mL（VU-EA-6），对于羟基自由基测定，30%抑制浓度值为0.58 μg/mL（VU-EA-1）、0.57 μg/mL（VU-EA-5）和0.70 μg/mL（VU-EA-6）。总之，笃斯越桔具有强大的抗氧化活性，黄酮类化合物被分离为主要活性成分。
