Wenzig Eva M, Oleszek Wieslaw, Stochmal Anna, Kunert Olaf, Bauer Rudolf
Institute of Pharmaceutical Sciences, Department of Pharmacognosy, University of Graz, Universitaetsplatz 4, 8010 Graz, Austria.
J Agric Food Chem. 2008 Oct 8;56(19):8885-90. doi: 10.1021/jf801289m. Epub 2008 Sep 9.
Yucca schidigera Roezl. (Agavaceae) has been traditionally used to treat a variety of diseases including arthritis and rheumatism. Phenolic constituents isolated from yucca bark, such as resveratrol, trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, and the yuccaols, have been shown to possess various activities in vitro, such as antioxidant, radical scavenging, iNOS expression inhibitory, and platelet aggregation inhibitory effects. In the present study, the influence of a phenolic-rich fraction from yucca bark and of its main phenolic constituents on key enzymes of arachidonate metabolism was investigated. The fraction and the pure phenolics were shown to inhibit COX-1, COX-2, and LTB 4 formation by 5-LOX in vitro to different extents. The degree of COX-1 inhibition was found to be strongly dependent on the substitution pattern of ring B of the stilbenic moiety. The same trend was observed for the COX-2 inhibitory potential, which was, however, in general much lower for the yuccaols as compared with resveratrol. Resveratrol was also the only compound possessing an LTB 4 formation inhibitory activity. The inhibitory activity on key enzymes of arachidonate metabolism observed in this study might contribute to the explanation of the anti-inflammatory and antiplatelet effects observed for Y. schidigera and its phenolic constituents.
丝兰（龙舌兰科）传统上被用于治疗多种疾病，包括关节炎和风湿病。从丝兰树皮中分离出的酚类成分，如白藜芦醇、反式-3,3',5,5'-四羟基-4'-甲氧基芪以及丝兰醇，已显示在体外具有多种活性，如抗氧化、自由基清除、诱导型一氧化氮合酶表达抑制和血小板聚集抑制作用。在本研究中，研究了丝兰树皮中富含酚类的部分及其主要酚类成分对花生四烯酸代谢关键酶的影响。该部分和纯酚类在体外均显示出不同程度地抑制COX-1、COX-2和5-脂氧合酶介导的白三烯B4生成。发现COX-1的抑制程度强烈依赖于芪类部分B环的取代模式。COX-2抑制潜力也观察到相同趋势，然而，与白藜芦醇相比，丝兰醇的抑制潜力总体上要低得多。白藜芦醇也是唯一具有白三烯B4生成抑制活性的化合物。本研究中观察到的对花生四烯酸代谢关键酶的抑制活性可能有助于解释丝兰及其酚类成分所观察到的抗炎和抗血小板作用。
