香蜂草可能經由調節單胺類神經傳導物質 而具有抗憂鬱效果

Abstract

憂鬱症已被世界衛生組織（WHO）列為21世紀三大疾病之一。以失能調整人年（disability adjusted life year, DALY）估算，預估於2030年憂鬱症將會成為高負擔疾病第一位（WHO, 2008）。而我國行政院衛生署2010統計顯示國人自殺死亡人數自民國86年起進入國人10大死因之列，並長達12年之久。憂鬱症的病理至今尚未完全明瞭，而有學者提出單胺類假說，指出腦中神經傳導物質失調與憂鬱症相關，並以此開發出多種抗憂鬱藥物。在抗憂鬱藥物的治療下，不僅會造成醫療成本急遽增加，且因抗憂鬱藥物的副作用使病人治療順從性不高，因此發展替代療法之保健素材是具有極大發展潛力。本研究欲探討香蜂草之抗憂鬱效果。由文獻指出，香蜂草（Melissa officinalis L.）可以治療因神經緊張所引起的痙攣、失眠或消化不良等症狀。香蜂草所含的多酚類成分─迷迭香酸（rosmarinic acid, RA），亦被研究證實具有神經保護作用。因此本實驗是使用香蜂草水萃物及其可能活性成分RA進行急性期（一天）及亞急性期（十天）動物試驗，皆以強迫游泳試驗（forced swimming test, FST）作為誘導大鼠產生類憂鬱症狀的實驗模式來進行研究，分析強迫游泳時的類憂鬱行為並且以HPLC分析腦部神經傳導物質的濃度。結果顯示，無論於急性期或亞急性期，給予香蜂草水萃物及RA皆可減少強迫游泳試驗中不活動時間之類憂鬱行為，並且在亞急性試驗發現，給予香蜂草水萃物可顯著增加游泳時間。進一步分析腦中單胺類神經傳導物質發現，急性試驗中，香蜂草水萃物及RA有顯著降低單胺類神經傳導物質代謝率；亞急性期中，香蜂草水萃物不僅降低單胺類神經傳導物質代謝率，更具有顯著提升單胺類神經傳物質的濃度。綜合以上結果，香蜂草水萃物及可能活性成分RA確實可能可透過調節單胺類神經傳導物質達到抗憂鬱效果。

According to the World Health Organization (WHO) statistics in 2008, major depressive disorder will become the first leading disability disease in the world in 2030. Therefore, it is necessary for investigating the pathophysiology of depression and the antidepressant therapeutics. However, depression pathologies are multifactorial. Monoamine dysregulation hypothesis is one of major causes of depression. The antidepressants used in clinics nowadays bring a lot of side effects. Thus, looking for the alternative therapies and prevention strategies for depression are very important issues. Melissa officinalis L. (Lemon balm), herbal medicine, has traditionally been attributed with sedative, sleep aid and memory enhancing effects. In a previous study, it was demonstrated that rosmarinic acid which is one of phenolic acids in lemon balm produces antidepressive-like and neuroprotective activities. Therefore, the aim of this study is to investigate the antidepressant effects of water extract lemon balm and rosmarinic acid by evaluating the animal behavior in forced swimming test and the content of monoamine neurotransmitters in brain. Our results showed that in acute and subacute test, water extract of lemon balm and rosmarinic acid exhibited significantly reduction of immobility time in forced swimming test, and increased swimming time in subacute test. Further analysis on monoamines indicated that the water extract of lemon balm and rosmarinic acid significantly decreased the monoamines turnover rate in acute test. In subacute test, the water extract of lemon balm not only markedly decreased the monoamines turnover rate but increased monoamines. In conclusion, water extract of lemon balm has antidepressant like effects possibly via the regulation of monoamine neurotransmitters. Moreover, rosmarinic acid might be active compound in lemon balm.