倒卵葉楠根部、五掌楠莖部之化學成分及生物活性之研究

摘要倒卵葉楠 (Macilus obovatifolia (Hay.) Kanehira & Sasaki) 為樟科 (Lauraceae) 植物，多為常綠小喬木或灌木，主要分布於恆春半島，為台灣固有種。高雄醫學大學藥用植物學研究室對台灣產植物約1,400種進行活性篩選，發現本植物根部之甲醇抽出物具抗氧化及細胞毒之活性。本植物根部之化學成分及活性未被完全研究，由於根部之乙酸乙酯可溶部及正丁醇可溶部具抗氧化活性層，利用活性導向分割法分離出四個新的lignan類化合物：epi-henricine B (539)、混合物threo-(7ʹR,8ʹR or 7ʹS,8ʹS)-methyl machilusol D (540) 和threo-(7ʹS,8ʹS or 7ʹR,8ʹR)-methyl machilusol D (541)、isofragransol A (542) 以及24個已知化合物，其中化合物542和fragransol A (547) 是以混合物狀態存在。以上化合物皆以各種圖譜分析來決定結構。活性試驗中，539、licarin A (33)、guaiacin (2)、 (±)-syringaresinol (140)、(–)-epicatechin (23) 具有清除ABTS自由基的能力，SC50值在20分鐘內分別為11.70 ± 0.46、12.3 ± 1.1、11.0 ± 0.1、10.6 ± 0.3和 9.5 ± 0.2 μM。kachirachirol B (17) 對於NCI-H460 cell line具有細胞毒活性，IC50值為 3.12 μg/ml. 五掌楠 (Neolitsea konishii (Hay.) Kanehira & Sasaki) 為樟科新木薑子屬，多為常綠小喬木，主要分布於琉球及台灣。經活性篩選後，發現其莖部之甲醇萃取物具有抑制Escherichia coli β-glucuronidase (eβg)、抗血小板凝集及抗發炎活性。過去其莖部曾被分離出19個已知化合物，但無eβg活性之研究，因此本研究採取五掌楠莖部進行化學成分分析及生物活性研究。由乙酸乙酯可溶部利用活性導向分割法分離出一個新的1,3-diphenylbutanoid類化合物：(−)-konishibutanin (551)、兩個新的lignan類化合物：neokoninins A 和B (552 和553)，以及20個已知化合物。以上化合物皆由各種圖譜分析決定結構。活性試驗中，132-hydroxy-(132-R)-pheophytin a (455) 具有抑制eβg活性，抑制率為88 %，trans-9,9'-O-di-(E)-feruloyl-(−)-secoisolariciresinol (557) 具有抑制U46619凝集因子和fMLP誘導超氧陰離子的活性，IC50值分別為7.89 ± 0.35及2.43 ± 0.03 μM。

關鍵字

倒卵葉楠；五掌楠；樟科；抗氧化活性；抑制大腸桿菌葡萄醣醛酸酶活性；抗發炎活性；抗血小板凝集活性

並列摘要

Abstract Machilus obovatifolia (Hay.) Kanehira & Sasaki (Lauraceae) is a small evergreen tree, endemic to Taiwan, and distributes in Hengchun Peninsula. In a series of studies on the active chemical constituents of Formosan plants, over 1,400 species were screened for anti-oxidantive and cytotoxic activities in vitro, the methanolic extracts of this plant have been shown anti-oxidantive activity and cytotoxicity. The phytochemistry and biological activities of its root have not been extensively studied. Bioassay-guided fractionation of the root of Machilus obovatifolia led to the isolation of four new lignans, epi-henricine B (539), mixture of threo-(7ʹR,8ʹR or 7ʹS,8ʹS)-methyl machilusol D (540) and threo-(7ʹS,8ʹS or 7ʹR,8ʹR)-methyl machilusol D (541), and isofragransol A (542), along with 24 known compounds. The compounds 542 and fragransol A (547) were obtained as isomeric mixture. Among these isolates, guaiacin (2), (–)-epicatechin (23), licarin A (33), (±)-syringaresinol (140), and 539 showed ABTS cation radical scavenging activity, with SC50 values of 11.0 ± 0.1, 9.5 ± 0.2, 12.3 ± 1.1, 10.6 ± 0.3, and 11.7 ± 0.5 μΜ in 20 min, respectively. In addition, kachirachirol B (17) showed cytotoxicity against the NCI-H460 cell line with IC50 value of 3.12 μg/ml. Neolitsea konishii (Hay.) Kanehira & Sasaki (Lauraceae) is a small evergreen tree and distributes in Ryukyus and Taiwan. In a bioactivity screening program on the Formosan plants, the methanolic extracts of the stem of Neolitsea konishii have been shown anti-eβg, anti-platelet aggregation and anti-inflammatory activities. 19 known compounds had been isolated from the stem of this plant previously. The anti-eβg activity of the stem of N. konishii have not been investigated. Therefore, the aim of this study is the isolation of chemical constituents and evaluation of their biological activities. Bioassay-guided fractionation of the stem of N. konishii led to isolation of one new 1,3-diphenylbutanoid, (−)-konishibutanin (551) and two new lignans, neokoninins A and B (552 and 553), along with 20 known compounds. Among the isolates, 132-hydroxy-(132-R)-pheophytin a (455) exhibited potent anti-eβg activity with inhibition ratio of 88 %. In addition, trans-9,9'-O-di-(E)-feruloyl-(−)- secoisolariciresinol (557) showed potent inhibitory U46619 factor and fMLP-induced superoxide generation in human neutrophils activity with IC50 values of 7.89 ± 0.35 and 2.43 ± 0.03 μM.

並列關鍵字

Macilus obovatifolia ； Neolitsea konishii ； Lauraceae ； anti-oxidantive activity ； anti-Escherichia coli β-glucuronidase (eβg) activity ； anti-inflammatory activity ； anti-platelet aggregation activity