| 摘要: | 鱷嘴花 (Clinacanthus nutans (Burm. f.) Lindau) 為爵床科 (Acanthaceae) 鱷嘴花屬植物，以全株或葉片入藥，又名憂遁草或沙巴蛇草。該植物為中國南部至西南部地區以及東南亞地區，如泰國、印尼、馬來西亞等國家的原生植物。鱷嘴花傳統醫療上用於治療炎症、皰疹病毒感染和癌症等。迄今為止，許多研究已經證實鱷嘴花具抗發炎、抗氧化、抗菌、抗病毒、抗增殖和抗腫瘤等作用。
儘管發現了鱷嘴花可能的活性成分，並對這些成分進行了可能的藥理活性研究，但中草藥標準化一直是限制中草藥發展的關鍵瓶頸。為了確保大眾用藥安全，確認中草藥的基原、一致性和重現性有其必要。為了達到世界衛生組織 (WHO) 傳統醫藥戰略的目標: “通過對產品、執業過程和從業人員的管理來促進中醫藥使用的安全性和有效性” 。制定良好的品質管制方法是必要的，以做為產品品質規範的參考標準。
為了順應國際潮流，本研究目的為：一、整理並回顧已發表之鱷嘴花藥理研究成果，為進一步開發利用和研究鱷嘴花提供參考；二、開發基原鑑定方法；三、依藥典標準開發方法，提出鱷嘴花品質規格建議值；四、執行鱷嘴花抗氧化活性測試。
此論文分為兩個主要部分：鱷嘴花文?Y?鰣z (systematic review) 與質量控制 (Quality control) 研究。該綜述總結了鱷嘴花藥理作用、毒理學研究和化學成分相關研究。根據文獻回顧結果，發現鱷嘴花具有作為藥用植物的潛力。由於品質因素直接反映了中草藥的安全性和有效性，因此，為確保中草藥上市販賣前的品質，建立品質管制標準與方法極其重要。
本研究赴馬來西亞和臺灣各地草藥零售商、批發商和草藥栽培基地收集了十批鱷嘴花，並依照藥典標準開發方法，進行外觀性狀鑑定、顯微鑑定、化學規格、化學分析(薄層層析、高效液相層析)、安全性評估 (農藥殘留、黃麴毒素、二氧化硫)和抗氧化活性等實驗。
鱷嘴花可經由外部形態及顯微特徵有效地進行品種鑑定。化學分析揭示了薄層層析與高效液相層析以夏佛塔?? (schaftoside) 作為指標成分；薄層層析額外以羽扇豆醇 (lupeol) 和β-穀固醇 (β-sitosterol) 做為指標成分。本研究建立的薄層層析與高效液相層析方法均優於或修訂自藥典及專著所建議的實驗方法。
本研究藉由重現性、精密度和穩定性測試驗證了所開發高效液相層析方法。高效液相層析指紋圖譜還為品質管制提供了替代分析工具，並能充分呈現鱷嘴花化學成分組成，以利未來更進一步研究。
本研究亦進行五項化學規格實驗，包含測定總灰分、酸不溶性灰分、乾燥減重、水抽提物、50％乙醇抽提物和70％乙醇抽提物，實驗結果發現部分鱷嘴花批次超出了藥典的化學規格規範值。因此，本研究針對化學規格提出新建議值。
在安全性評估方面，本研究檢測真菌毒素(黃麴毒素)、農藥殘留和二氧化硫。值得一提的是實驗結果發現僅在新鮮樣品檢測出合格範圍內的黃麴黴毒素(B1和B2) 。所有批次均未檢出農藥殘留和二氧化硫。
依據鱷嘴花抗氧化活性研究結果，發現其葉子的抗氧化活性比莖來得更高。然而，若與抗壞血酸和蘆丁(均為強抗氧化活性對照成分)相比，無論葉和莖都被認為具有較弱的抗氧化活性。
總結來說，本研究所開發的品質管制實驗方法與規格建議值，可作為鱷嘴花品質評估參考。
Clinacanthus nutans (Burm. f.) Lindau (C. nutans), a native plant from the family of Acanthaceae is endemic in southern to southwestern regions of China as well as Southeast Asia especially in Thailand, Indonesia and Malaysia. It has been used traditionally in the treatment of inflammation, herpes viral infection and cancer. Research to date on its pharmacological action had shown some anti-inflammatory, anti-oxidative, antibacterial, antiviral, antiproliferative and antitumorigenic effects.
Despite finding potential bioactive ingredients and search for the possible pharmacological effects of these chemical compounds, standardization of the herb is always the key bottlenecks restricting the development of herbal medicine. There is a need of ensuring the authentication, consistency and reproducibility of the herb to assure the public safety. In order to meet the objective of WHO traditional medicine strategy: “to promote the safe and effective use of TCM through the regulation of products, practices and practitioners”, it is necessary to develop good quality control methods as a reference in regulating products.
Hence, in order to cope with the international trend, this study aimed: 1) to review current available pharmacological studies of C. nutans; 2) to develop an identification method for C. nutans; 3) to provide quality specification of C. nutans according to the pharmacopoeias standard; and 4) to examine its antioxidant activity.
The thesis was divided into 2 main components: a comprehensive review precedes the quality control studies. The review summarized the studies related to pharmacological actions of C. nutans, the toxicology studies and known phytochemical constituents available in C. nutans. Based on the review, it was found that C. nutans has its potential as a medicinal plant. Since quality reflect directly to the safety and effectiveness of the plant, it is indeed important to have a quality control standards and methods to measure the quality before it is marketed.
Ten batches of C. nutans were collected from the herbal retailers, wholesalers or direct from the herbal plantations around Malaysia and Taiwan. A series of experiments from morphological (macroscopic and microscopic) identifications, chemical analysis (thin layer chromatography, high performance liquid chromatography) to safety assessments and antioxidant activity were carried out according to the pharmacopoeia standards.
Macroscopic and microscopic identification allowed C. nutans to be readily distinguished through its special features. Chemical profiling revealed schaftoside was chosen as the standard marker for both TLC and HPLC analysis. Lupeol and β-sitosterol were available based on TLC results but were not selected as reference standards in HPLC. Both TLC and HPLC methods were upgraded and revised as compared to the suggested method in monograph and pharmacopoeia.
HPLC method was validated based on reproducibility, precision and stability tests. The HPLC chromatographic fingerprint also provided an alternative analytical tool for quality control and acted as an approach to express a various pattern of chemical ingredients available for future studies.
The determination of ash, acid-insoluble ash, total loss of drying (water content), extractives (water, 50% and 70% ethanol (EtOH) as solvents) were performed and some of the results were found to be exceeding limits of monograph and pharmacopoeia. Hence, new suggestion of limit for each test was proposed.
In terms of safety measurements, the presence of mycotoxins (aflatoxins), pesticide residues and sulfur dioxide were tested. The highlight of these tests was all batches of the fresh samples were detected with aflatoxin (B1 and B2) but at a minimal amount (within the permitted range). None of the samples were detected with pesticide residues and sulfur dioxide.
Based on the antioxidant activity studies, leaves of C. nutans exhibited higher antioxidant activities compared to the stems. However, when compared to the ascorbic acid and rutin (strong antioxidant positive control), both leaves and stems were considered to have weak antioxidant activities.
Concisely, the study suggested methods and proposed limits that can be used as the reference for the quality control of the Clinacanthus nutans (Burm. f.) Lindau. |
