伽羅木醇型土肉桂葉子精油之抗焦慮活性

伽羅木醇型土肉桂（Cinnamomum osmophloeum Kaneh. ct. linalool）為臺灣特有的土肉桂6種化學品系之一，本研究探討不同植株、不同採收季節及不同成熟度對精油收率、成分和含量的影響。試驗以水蒸餾法萃取伽羅木醇型土肉桂葉子精油，再以氣相層析−質譜儀（GC-MS）分析其成分，並以火焰離子偵測器氣相層析儀（GC-FID）配合異構物管柱確定成分之絕對立體組態及定量成分；另外，本研究也評估不同萃取時間（1 h、2 h、6 h和10 h）對精油收率和成分的影響。試驗結果發現，12株伽羅木醇型土肉桂葉子精油收率之平均值為3.7%，平均Linalool含量為90%，其絕對立體組態為S-(+)-Linalool，在每克絕乾成熟葉子含量平均為31.0 mg。此外，伽羅木醇型土肉桂葉子精油收率和S-(+)-Linalool含量並不會隨著季節氣候的變化而有大幅動的變動，其含量相當穩定，又比較不同成熟度的葉子時，以成熟葉含量較為豐富。同時從不同萃取時間證實，以水蒸餾法萃取精油，只需要1 h即可獲得全部精油及純的S-(+)-Linalool。本研究進一步以焦慮症動物模式（開放場地試驗、光暗試驗及高腳十字迷宮試驗）評估伽羅木醇型土肉桂葉子精油及其主成分S-(+)-Linalool之抗焦慮活性。將4週齡大的ICR小白鼠，利用口服灌餵高低劑量（500及250 mg/kg）伽羅木醇型土肉桂葉子精油、500 mg/kg S-(+)-Linalool、500 mg/kg R-(−)-Linalool及市售抗焦慮藥物Trazodone hydrochloride（75 mg/kg），連續餵食及記錄體重變化率14天後，進行焦慮症動物模式。動物模式後犧牲小鼠，並立即分析腦組織（大腦皮質前區、海馬迴和紋狀體）神經傳導物質含量及檢測血液中血糖、總膽固醇、三酸甘油酯、Aspartate aminotransferase（AST）和Alanine aminotransferase（ALT）含量差異。試驗結果顯示，伽羅木醇型土肉桂葉子精油及其主成分S-(+)-Linalool，具有降低小鼠在開放場地試驗、光暗試驗及高腳十字迷宮試驗的焦慮情緒，並且不會影響其活動力，而降低焦慮之功效主要源自於小鼠腦組織（大腦前區皮質和海馬迴）的單胺類神經傳遞物質濃度降低；另外，從紋狀體的多巴胺（Dopamine）的濃度增加，可知道伽羅木醇型土肉桂葉子精油及其主成分S-(+)-Linalool具有開發成為改善帕金森氏症病症的潛力。此外餵食S-(+)-Linalool小鼠體重增加率從第9天開始較控制組減少35%及其血液中三酸甘油酯值較控制組下降26%，同時不會增加肝臟、腎臟和脾臟負擔也無臟器病變的發生。綜合上述結果顯示，伽羅木醇型土肉桂葉子精油來源、成分及含量穩定，且具有優良抗焦慮功效，因此具有發展為低成本、低副作用及高品質的抗焦慮食品及保健產品之潛力。

關鍵字

絕對立體組態鑑定；抗焦慮活性；伽羅木醇型土肉桂；保健產品；葉子精油； S-(+)-Linalool ；單胺類神經傳導物質

並列摘要

Cinnamomum osmophloeum Kaneh. ct. linalool is one chemotype of the indigenous cinnamon in Taiwan. In this study, hydrodistillation was used for extracting the leaf essential oil (LEO) of C. osmophloeum ct. linalool collected from various plants and seasons, and GC-MS and GC-FID were used to examine variations and contents of chemical composition in LEOs. Moreover, the absolute configuration of the main constituent and its content of LEO were illustrated by GC-FID with chiral column. In addition, we also investigated the effect of the extraction time (1 h, 2 h, 6 h, and 10 h) on the yield of LEO and the content of main constituents. Results from this study revealed that the average LEO yield of 12 plants was 3.7%, and there were more than 90% linalool in them. The linalool in the LEO was proved to be pure S-(+)-linalool and its average content in 12 plants is 31.0 mg. Furthermore, there were no obvious differences in LEO yield and S-(+)-linalool content from various plants and seasons, and the mature leaves have more S-(+)-linalool content. On the other hand, we also identified that LEO and S-(+)-linalool from C. osmophloeum ct. linalool leaves can be completely extracted out by 1 h hydrodistillation. This study recorded the rate of weight changes in mice, and examined the anxiolytic potency of LEO from C. osmophloeum ct. linalool and its main constituent on 4-week ICR mice by using the following animal models, including open field test (OFT), light-dark test (LDT) and elevated plus maze test (EPT). After oral administrations of LEO (250 mg/kg and 500 mg/kg), S-(+)-linalool (500 mg/kg), R-(−)-linalool (500 mg/kg) and trazodone hydrochloride (75 mg/kg) for 14 days, their anxiolytic effects on mice behavior were evaluated, and rate of weight changes were recorded. Brain tissue and blood of the mice were collected after sacrifice for analyses. And then, monoamines in brain tissue sample (frontal cortex, hippocampus and striatum) were measured and blood biochemical values (Glucose, Total cholesterol, Triglyceride, Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT)) in mice blood were also assessed. The results showed that LEO from C. osmophloeum ct. linalool and S-(+)-linalool can significantly increase time spending in the center area of OFT, illuminated area of LDT and open arms of EPT without side effects on locomotor activity, indicating excellent anxiolytic responses. It was also found that the levels of the neurotransmitters (serotonin, dopamine and norepinephrine) decreased in frontal cortex and hippocampus, which could result in the anxiolytic effects in animal models. In addition, mice administrated LEO from C. osmophloeum ct. linalool and S-(+)-linalool have increased the level of dopamine in striatum, indicating that LEO from C. osmophloeum ct. linalool and S-(+)-linalool could be used in Parkinson's disease treatment. We also found that body weight and triglyceride levels of mice after oral administration of S-(+)-linalool was less than control group. The injuries of liver and organ in mice were not observed in this study. The finding obtained suggested that LEO from C. osmophloeum ct. linalool and its major compound, S-(+)-linalool, possess anxiolytic properties without any side effects and thus support their potential uses as cheap and safe additives and health products with anxiolytic effects.

並列關鍵字

Absolute configuration ； Anxiolytics ； Cinnamomum osmophloeum Kaneh. ct. linalool ； Health products ； Leaf essential oil ； S-(+)-Linalool ； Neurotransmitters