臺灣蟲草屬真菌之類緣關係及生物活性物質之研究

Abstract

蟲草屬類群(Cordyceps-like)真菌廣泛地作為藥用用途或食品添加劑，在中華歷史及西藏中草藥文化中，作為珍貴藥材享譽盛名。一般而言，蟲草屬類群真菌可透過以下特點與其他真菌進行區分:柄狀子囊座、子囊殼排列方式、子囊的形態特徵及寄主。臺灣有關蟲草屬(Cordyceps)真菌之相關研究屈指可數並零星散佈於歷史文獻中。蟲草屬真菌能產生各式生物活性物質，例如: 蟲草素(Cordycepin)、腺苷(Adenosine)和各種酵素，也因此蟲草屬真菌常作為增能劑與民俗藥物，在傳統中醫學中更被認為有利於癌症與糖尿病的治療。本研究目的有三: (一)依據形態與親緣演化評估台灣地區之蟲草屬真菌之自然分類地位。(二)透過高效液相層析儀探討台灣蟲草屬真菌之菌絲溫水萃取液之蟲草素與腺苷含量。(三)比較台灣地區新採集之蟲草屬真菌與市面商用菌株之蟲草素與腺苷含量。研究期間，於臺灣各處採集共獲59株蟲草屬菌株，並於採後進行形態構造紀錄。利用單對與合併的基因序列片段(nrLSU、ITS、tef1-α、rpb1、rpb2)進行親源演化分析並評估自然分類地位。結合親源演化分析與形態鑑定，共發現七種蟲草屬新種(Cordyceps sp. nov. 1–7)與四隻蟲草屬新紀錄種(C. blackwelliae、C. lepidopterorum、C. jakajanicola與C. rosea)。同時，我們還描述了C. rosea完整世代的型態。高效液相層析結果表示所有新採集之蟲草屬菌株皆會產生腺苷。然而，只有三種蟲草屬真菌具有產生蟲草素的能力，分別為C. militaris、Cordyceps sp. nov. 4 (NTUCC 18-144)與Cordyceps sp. nov. 7 (NTUCC 18-145)。此外，我們的結果指出新採集之C. militaris (NTUCC 18-120) 比市售菌株具有更強的蟲草素生合成能力。

Cordyceps-like taxa are widely used for medicinal purpose or food additives and have been described as precious herbal medicine in ancient Chinese history and Tibetan social community. Generally, Cordyceps taxa are characterized by well-developed often stipitate stromata, arrangement of perithecia, ascospore morphology and host affiliation. Knowledge of the Cordyceps species in Taiwan is based on relatively few records that are scattered throughout the literature. Cordyceps species produce various bioactive compounds, such as cordycepin, adenosine and enzymes, which have been widely used as energizers and folk medicines that can be conducive to cancer and diabetes treatments in traditional Chinese medicines. The main purposes of this study were 1) to evaluate the natural classification of Cordyceps species in Taiwan based on morphology and phylogeny, 2) to investigate cordycepin and adenosine production of Cordyceps species in Taiwan by high-performance liquid chromatography (HPLC) based on the hot-water extract from its mycelium, 3) to compare the level of cordycepin production of the newly collected Taiwan Cordyceps isolates with commercially available Cordyceps species. A total of 59 fresh Cordyceps strains were collected and their morphological characteristics were recorded. Phylogenetic reconstruction using single and multi-loci (nrLSU+ITS+tef1-α+rpb1+rpb2) DNA sequences data were used to evaluate the natural classification of the new strains. Within this phylogenetic framework and considering the diagnostic morphological characters, seven new species (Cordyceps sp. nov. 1–7) were described. In addition, four new records, namely (C. blackwelliae, C. lepidopterorum, C. jakajanicola and C. rosea) were also made. Furthermore, we illustrated the holomorph of C. rosea for the first time. The results of our HPLC analyses showed that all isolates used in this study produced adenosine. However, only three Cordyceps species, namely C. militaris, Cordyceps sp. nov. 4 (NTUCC 18-144) and Cordyceps sp. nov.7 (NTUCC 18-145) proposed in this study were able to produce cordycepin. Moreover, our results indicated that C. militaris (NTUCC 18-120) collected in this study, produced a higher level of cordycepin compared to commercially available Ophiocordyceps sinensis and C. militaris.