土肉桂枝條抽出物之生物活性評估

Evaluation of bioactivities of Extractives from Twigs of Cinnamomum osmophloeum

蔡明桐(Meng-Thong Chua)

指導教授 ： 張上鎮

國立臺灣大學/生物資源暨農學院/森林環境暨資源學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.02566

摘要

土肉桂(Cinnamomum osmophloeum Kaneh)為台灣特有樹種之一。本研究目的係分析其枝條抽出成分和探討其生物活性。首先，以水蒸餾法萃取土肉桂枝條精油，再以氣相層析-質譜儀分析鑑定出其主成分為L-Bornyl acetate和Caryophyllene oxide，其含量分別為15.9%及13.0%。再以乙醇溶劑萃取枝條抽出物，並利用液相-液相分配分為正己烷、乙酸乙酯、正丁醇及水等4個分離部。至於生物活性評估則包括海蝦致死試驗、抗腐朽菌試驗、抗病媒蚊幼蟲試驗、抗發炎活性試驗及抗氧化活性試驗。由海蝦致死試驗結果發現，精油具有顯著的毒殺作用(LC50 = 28.2 μg/mL)，然而乙醇抽出物及其各分離部對海蝦並無太大毒性（LC50 > 500 μg/mL）。抗腐朽菌試驗結果亦顯示，精油對Lenzines betulina白腐菌和Laetiporus sulphureus褐腐菌具有不錯的抗菌活性，其IC50值分別為193.1及148.2 μg/mL。枝條乙醇抽出物及其各分離部則對此兩種菌皆沒有顯著的抑制效果(IC50 > 500 μg/mL)。由抗病媒蚊幼蟲試驗結果顯示，精油具不錯的抗病媒蚊幼蟲活性，對Aeades aegypti埃及斑蚊及Aeades albopictus白線斑蚊的LC50分別為64.5及80.3 μg/mL。除此之外，精油能有效抑制LPS誘發RAW 264.7小鼠巨噬細胞所生成之一氧化氮(NO)及前列腺素E2 (PGE2)，顯示其具良好之抗發炎活性。另外，利用DPPH自由基清除效應、超氧自由基補捉試驗、還原力測定、金屬螯合效果及脂質過氧化試驗等來評估枝條乙醇抽出物及其各分離部之抗氧化活性，同時亦測定其總酚含量。土肉桂枝條乙醇抽出物之正丁醇可溶部在DPPH自由基清除效應、超氧自由基補捉試驗、還原力測定、及脂質過氧化試驗均顯現最佳的效果，且其總酚含量亦最高(496.7 mg of GAE/g )。而土肉桂枝條乙醇抽出物之水可溶部則具有不錯的金屬螯合能力,其EC50值為1691.9 μg/mL因此，進一步由正丁醇可溶部分離出具抗氧化能力之Kaempferol-7-O-rhamnoside。綜合上述試驗結果顯示，土肉桂枝條精油具有不錯的抗腐朽、抗病媒蚊及抗發炎活性。然而乙醇抽出物具有相當好的抗氧化活性且對海蝦並沒有太大毒性，故頗具潛力開發為保健食品

關鍵字

土肉桂 ； 枝條 ； 精油 ； 抽出物 ； 海蝦致死活性 ； 抗腐朽活性 ； 抗病媒蚊幼蟲活性 ； 抗氧化活性 ； 總酚含量 ； 抗發炎活性

並列摘要

Cinnamomum osmophloeum Kaneh is an indigenous tree species that grows in Taiwan. Phytochemical characteristics and bioactivities of the C. osmophloeum twigs extractives were investigated in this study. The essential oil of C. osmophloeum’s twigs was obtained by hydrodistillation and its chemical constituents were further analyzed by GC-MS. The major compounds present in twig’s essential oil are L-bornyl acetate and caryophyllene oxide with a content of 15.9% and 13.0%, respectively. The twigs were also extracted with ethanol and followed by separating it by liquid-liquid partition to produce n-hexane, ethyl acetate (EtOAc), n-butanol (BuOH) and water soluble fractions. Extractives of C. osmophloeum twigs bioactivities were evaluated by various assays including brine shrimp lethality (BST), antifungal, mosquito larvicidal, anti-inflammatory and antioxidant assay. In the brine shrimp lethality assay, essential oil of C. osmophloeum’s twigs showed significant toxicity against Artemia salina Leach with a LC50 of 28.2 μg/mL, while twigs crude extractives and their derived fractions didn’t show any significant toxic effects because of their LC50 > 500 μg/mL. Essential oil of C. osmophloeum’s twigs also exhibited excellent inhibitory effects against Lenzines betulina and Laetiporus sulphureus in antifungal assay, with IC50 values of 193.1 and 148.2 μg/mL, respectively, while crude extractives and their derived fractions did not show any significant inhibitory effects against the fungi mentioned above (IC50 > 500 μg/mL)。In mosquito larvicidal assay, essential oil of twigs were also exhibited excellent activities against Aeades aegypti and Aeades albopictus with a LC50 value of 64.5 and 80.3 μg/mL, respectively, while other soluble fractions did not show any activities (LC50 > 400 μg/mL). Furthermore, essential oil from C. osmophloeum twigs exhibited excellent anti-inflammatory activities against nitric oxide (NO) production and prostaglandin E2 (PGE2) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. The antioxidant activities of C. osmophloeum extractives were carried out by using various antioxidant assays, including DPPH radical and superoxide radical scavenging assays, reducing power assay, lipid peroxidation by using mouse brain homogenates, and metal chelating ability assay. In addition, total phenolic contents were also determined. Results revealed that butanol soluble fraction exhibited the strongest performance in DPPH radical scavenging activity assay, superoxide radical scavenging assay, reducing power and lipid peroxidation by using mouse brain homogenates. Furthermore, butanol soluble fraction has the highest total phenolic contents (496.7 mg of GAE/g). Phenolic compounds were founded rich in C. osmophloeum twig extractives and thus, this is correlated well with their antioxidant activities. Water soluble fraction of C. osmophloeum extractives showed good metal chelating ability with an EC50 value of 1691.6 μg/mL. Consequently, kaempferol- 7-O-rhamnoside was isolated from BuOH soluble fraction. These results demonstrated that, essential oils of C. osmophloeum twig have excellent antifungal, mosquito larvacidal and anti-inflammatory activities. Ethanolic crude extractives of C. osmophloeum twigs have excellent antioxidant activities and did not show any toxic effects against brine shrimp, so it has good potential as a source for nature health products.

並列關鍵字

Cinnamomum osmophloeum ； twig ； essential oil ； extractives ； brine shrimp lethality ； antifungal activity ； mosquito larvicidal activity ； antioxidant activity ； total phenolics contents ； antiinflammatory activity

參考文獻

Chang, S. T., S. Y. Wang and C. L. Wu (2000) Evaluation of antitumor potential of lignans from Taiwania (Taiwania cryptomeriodies Hayata). (in Chinese) Quart. J. Chin. For. 33:277-282.

Committee of the Flora of Taiwan (1996) Flora of Taiwan 2nd Edition pp.445-446

Su, Y. C., C. L. Ho, E. I. C. Wang and S. T. Chang (2006) Antifungal activities and chemical compositions of essential oils from leaves of four eucalypts. T. J. For. Sci. 21:49-61.

Tung, Y. T., J. H. Wu and S. T. Chang (2005) Preliminary studies on the antioxidant activity of ethanolic extracts from the twig of Acacia confusa Merr. (in Chinese) Quart. J. Chin. For. 38:367-375.

Adams, R. P. (2001) Identification of essential oil components by gas chromatograpy/quadrupole mass spectroscopy. Allured, lllinois. 456 pp.