Agbor Gabriel A, Vinson Joe A, Oben Julius E, Ngogang Jeanne Y
Department of Chemistry, University of Scranton, Scranton, PA, 18510, USA.
J Herb Pharmacother. 2007;7(2):49-64. doi: 10.1300/j157v07n02_04.
Reactive oxygen species are known to play a role in numerous pathological conditions, and antioxidants from plant sources have been of great help in modulating this effect. This study assesses the methanolic extracts of the leaves of three Piper species (Piper guineense Schum and Thonn., Piper nigrum L. and Piper umbellatum L.) (Piperaceae) for their polyphenolic concentration and free radical scavenging activity. The Folin-Ciocalteu method was used to assess the polyphenolic concentration while the reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide radical, hydroxyl radical, nitric oxide scavenging and metal chelating activities were employed in studying the radical scavenging activity of the extracts. All three spices exhibited a marked polyphenolic concentration and dose dependent free radical scavenging activity. The free polyphenolic concentration of the three spices was in the order P. umbellatum (15.9 +/- 1.9 mg/g) > P. guineense (12.6 +/- 0.3 mg/g) > P. nigrum (9.8 +/- 0.8). The three Piper extracts exhibited a 79.8-89.9% scavenging effect on DPPH, an 85.1-97.9% scavenging effect on nitric oxide at a dose level of 10 mg/ml and a 47.1-51.6% scavenging effect on superoxide radical at a dose level of 8 mg/ml extraction. Piper extracts also exhibited a 57-76.1% scavenging effect on hydroxyl radical at 5 mg/ml, a 0.4-0.6 reducing power and an 88.3-93.9% metal chelating activity at a dose level of 8 mg/ml of extract. Thus, these Piper species can play a role in the modulation of free radical induced disorders.
已知活性氧在多种病理状况中发挥作用，而植物源抗氧化剂在调节这种作用方面有很大帮助。本研究评估了三种胡椒属植物（几内亚胡椒Piper guineense Schum和Thonn.、黑胡椒Piper nigrum L.以及伞叶胡椒Piper umbellatum L.）（胡椒科）叶片的甲醇提取物的多酚浓度和自由基清除活性。采用福林-西奥尔特法评估多酚浓度，同时利用还原能力、1,1-二苯基-2-苦基肼（DPPH）、超氧阴离子自由基、羟自由基、一氧化氮清除及金属螯合活性来研究提取物的自由基清除活性。所有三种香料均表现出显著的多酚浓度和剂量依赖性自由基清除活性。三种香料的游离多酚浓度顺序为：伞叶胡椒（15.9±1.9毫克/克）＞几内亚胡椒（12.6±0.3毫克/克）＞黑胡椒（9.8±0.8毫克/克）。三种胡椒提取物对DPPH的清除率为79.8 - 89.9%，在剂量水平为10毫克/毫升时对一氧化氮的清除率为85.1 - 97.9%，在提取剂量水平为8毫克/毫升时对超氧阴离子自由基的清除率为47.1 - 51.6%。胡椒提取物在5毫克/毫升时对羟自由基的清除率为57 - 76.1%，在提取物剂量水平为8毫克/毫升时还原能力为0.4 - 0.6，金属螯合活性为88.3 - 93.9%。因此，这些胡椒属植物可在调节自由基诱导的疾病中发挥作用。
