人工培養的北蟲草子實體之急毒性及基因毒性評估

The Acute Toxicity and Genotoxicity Evaluations of Cultured Fruiting Body of Cordyceps militaris

中華冬蟲夏草，也就是冬蟲夏草，它是一種中國傳統滋補的昂貴中草藥材，具有抗糖尿病、抗腫瘤、免疫調節、抗氧化及抗老化等活性。由於天然中華蟲草的產量稀少。價格昂貴，因此市面上出現了很多偽品或仿冒品時，人們也就開始尋找與冬蟲夏草有相同藥理活性的替代品。目前市面上常常使用較便宜的北蟲草作為冬蟲夏草的天然替代品。但北蟲草之價格仍然昂貴，故有許多相對較便宜人工培養的北蟲草出現在市面上，因此本研究計畫評估人下培養的北蟲草子實體是否具有急毒性及基因毒性。在急毒性方面，給予SD大白鼠單一大劑量2000mg/kg人工培養的北蟲草子實體後，測量第七天及第十四天的體重。接著以微核實驗在螢光顯微鏡下計數1000個網狀細胞中有多少個是含有微核的網狀細胞，來評估人工培養的北蟲草子實體是否其基因毒性。微核試驗為一種方便、便宜，快速的方法，而mitomycin C為一種已知具有細胞毒性的抗癌藥物，在本實驗中作為誘導微核的正對照組。在給予SD大白鼠2000mg/kg人工培養的北蟲草子實體後48小時，收集股骨的骨髓細胞偵測微核數目。另外，在ICR小鼠，則是同樣給予單一大劑量2000mg/kg人工培養的北蟲草子實體後，分別在第24、48及72小時，收集眼窩血偵測微核數目。此外，在ICR小鼠，也分別每天重複給予125mg/kg至1000mg/kg人工培養的北蟲草子實體達七天，以評估其是否具有基因毒性。從我們的實驗結果得知，給予單一大劑量2000mg/kg人工培養的北蟲草子實體，在SD大白鼠的體重與對照組〈給予methylcellulose〉之間並無明顯差異，也無死亡狀況，微核數目在兩組之間也無明顯差異，因此初步認為人工培養的北蟲草子實體在SD大白鼠並不其急毒性及基因毒性。此外，不管是單一大劑量〈2000mg/kg〉給予後3天，或是125~100mg/kg的劑量連續重複給予七天，微核數目在兩組之間也無明顯差異，故初步認為人工培養的北蟲草子實體在ICR小鼠一樣不具有基因毒性。

The Chinese herbal drug DongChongXiaChao. a medicinal and edible mushroom originating from the fungus Cordyceps sinensis (CS), is beneficial to human health in a number of aspects since it possesses anti-diabetic, anti-tumour, immunomodulatory, anti-oxidative and anti-ageing activity. Because CS is so scarce in nature and high in price, a counterfeit and a mimic derived are frequently found in markets. Cordyceps militaris (CM) is another species of Cordyceps spp., which has also been used as a folk medicine in China for a long time and it is a popularly using and cheaper natural of CS. Recently, a huge amount of effort has been devoted to cultivating CM in a controlled environment in order to improve its availability. The purpose of this study was to evaluate whether the cultured fruiting body of CM has acute toxicity and genotoxicity at SD rats and ICR mice. In the acute toxicity, a single maximum dose (2000 mg/kg) of CM were given by oral gavage to SD rats, we had measured the body weights of all animals at the 7th and 14th days. Then we planed to evaluate the genotoxicity of cultured fruiting body of CM by the micronucleus test. The micronucleus test is a convenient, cheap and fast assay to check genotoxicity by counting how many reticulocytes contained micronuclei (MN) in 1000 reticulocytes. Mitomycin C (MMC) is a famous anti-tumor cytotoxic drug, we used it as a positive control to induced MN. We had sampled bone marrow cells of SD rats at the 48 hours after 2000 mg/kg CM treatment, and collected the orbital peripheral blood of ICR mice at the 24, 48 and 72 hours with same treatment. We also evaluated the possible genotoxicity of CM in ICR mice with multiple doses (125~1000 mg/kg) for 7 days. The body weights and MN numbers were not significant difference between the groups of SD rats treated with CM or methylcellulose. Thus, we suggest that CM was no acute toxicity and genotoxicity at SD rats when a single maximum 2000 mg/kg dose was orally administered. The MN numbers were not significant difference between the groups of ICR mice treated with CM or methylcellulose. Thus, the cultured fruit body of CM also did not induce genotoxicity when treatment with a single maximum dose (2000 mg/kg) for 3 days or multiple doses continuous for 7 days in ICR mice.