| 摘要: | 蕨類植物不論在世界傳統醫學或是民間用藥上都具有廣泛的應用價值。瓶爾小草科植物錫蘭七指蕨 (Helminthostachys zeylanica (L.) Hook.) 為台灣民間常用的抗發炎草藥，同時廣泛使用於中國、東南亞、印度等地區。在抗發炎活性預試驗中發現錫蘭七指蕨的各種分劃層在10 ?慊/mL的濃度下對抑制人類嗜中性白血球超氧自由基生成有明顯的活性 (Inh %, 80.6~89.5 %)，因此本研究對錫蘭七指蕨抗發炎之活性成分物質作進一步的分離與研究。本研究使用高效液相層析系統從錫蘭七指蕨根莖部的正己烷分劃層與乙酸乙酯分劃層純化得十八個化合物，並經由各種光譜分析確認其結構式，已完全確定這十八個的結構，其中包含一個新骨架的聚乙醯生合成物(聚乙醯生合成物)：6-hydroxy-8-tetradecyloxacyclooctan-2,7-dione (16)；十二個黃酮類新化合物：ugonins M~X (4-15) 以及五個已知黃酮類化合物：ugonins J~L (1-3)、5,4'-dihydroxy-4",4"-dimethyl-5"-methyl-5"H-dihydrofurano[2",3": 6,7]flavanone (17) 與quercetin (18)。這些化合物經進行抗發炎的初步活性篩選 (包含抑制超氧自由基產生與抑制彈性蛋白酶釋放試驗)以及乳酸去氫酶 (LDH) 毒性試驗，發現化合物2、3、4、6、8、10、11、13、16具有抑制超氧自由基產生之活性；而化合物3、4、6、8、9、10、11、13、15、16則具抑制彈性蛋白酶釋放之活性，在所有測試化合物中只有5具有LDH毒性。根據活性篩選結果，本研究進一步的討論這些化合物的結構與抑制彈性蛋白酶釋放活性關係，發現牻牛兒基(geranyl group) 與黃酮主結構的合環、牻牛兒基結構上的羥基存在與黃酮主結構上BC環的共平面可能都是影響抑制彈性蛋白酶釋放活性的因素。除此之外，本研究進一步的推測此ugonin類黃酮化合物的生合成路徑。
Due to the application of modern isolation techniques and extensive application of biochemistry, it increasingly become important to search new entities from traditional herbs or folk medicine as new drugs to treat human diseases. Among them, ferns are important medicinal resources in many human societies. Helminthostachys zeylanica (L.) Hook. (Ophioglossaceae), also known as “Ding-Di-U-Gon” in Chinese, has been used for centuries in the treatment of inflammation and various hepatic disorders. This medicinal fern is also used in India and Sri Lanka. Preliminary bioactivity screening indicated that the ethyl acetate extract of H. zeylanica had a potent inhibitory effect on human neutrophil-generated superoxide anions in the presence of formyl-L-methionyl-L-leucyl-L-phenylalanine/ cytochalasin B (FMLP/CB) at 10 ?慊/mL. Therefore, investigation on the bioactivity of secondary metabolites isolated from H. zeylanica was ocurried out. Herein, this thesis reported on the constituents of the rhizomes of H. zeylanica, isolated and purified by reversed-phase semi-preparative HPLC, including: 12 new flavonoids (ugonins M-X (3-15)), one new acetogenin (16), along with five known flavonoids (ugonins J~L (1-3)), 5,4'-dihydroxy-4",4"-dimethyl-5"-methyl-5"H-dihydrofurano[2",3":6,7]fla-vanone (17), and quercetin (18). The structures of the new isolates were elucidated by spectroscopic and chemical methods. The inhibitory effects of these isolates on the generation of superoxide, release of elastase by human neutrophils in response to FMLP/CB, and release of lactate dehydrogenase been evaluated. Among them, compounds 2, 3, 4, 6, 8, 10, 11, 13, and 16 showed inhibitory activities on superoxide anion generation by human neutrophils in response to FMLP/CB (IC50 values: 0.45~5.82 μM). Cpmpounds 3, 4, 6, 8, 9, 10, 11, 13, 15, and 16 exhibited inhibitory activities on elastase release by human neutrophils in response to FMLP/CB (IC50 values: 0.43~3.84 μM). Of all the compounds examined, only 5 showed toxicity in the lactate dehydrogenase release assay. Furthermore, we had a discussion about the structure-activity-relationship (SAR) of these isolates. The ugonins isolated in this experiment also provided direct evidence of biosynthesis, For example, ugonin X is an important intermediate of ugonins H and I in the biosynthesis from flavonols; ugonins P and S are important intermediates in the biostnthesis of ugonin L from flavones. |
