The Secondary Metabolites Of Xylaria Sp. NCY2 And Tubercularia Sp. TF5 Isolated From Gymnosperm Plants

Endophytes are the microbes that colonize living, internal tissues of plants without causing any immediate, overt negative effects. They are natural constituent of microecosystem inside plants and have established a harmonious relationship with their hosts in the long-term evolution process. Endophytes represent a dependable source of bioactive and chemically novel compounds since their secondary metabolites are abundant.Gymnosperm plants are the most ancient xylophyte, many of them are pharmaceutical plants. China has very rich gymnosperm plants. Studies on endophytic fungi will promote the development of microbial medicine and help the protection of the valuable and rare plants. We have studied the secondary metabolites of the endophytic fungi from gymnosperm plants in Fujian province, Taxus mairei and Torreya jackii Chun, in order to discover the structure novel compounds with potential for new drugs.92 strains of endophytic fungi were obtained from the bark of Taxus mairei and Torreya jackii Chun collected in Shaowu and Sha countries, Fujian province. The antitumor and antimicrobial activities of the fermentation broths of these endophytic fungi were tested. The results showed that the fermentation broths of 45 strains (about 48.9% of the total strains isolated) show noticeable growth inhibition against one or more indicator fungi, and about 19.6% of them have high activities against fungi; 15 (about 16.3%) of them have inhibition activities against HeLa, KB and/or HL-60 tumor cells with the ID₅₀≤1:50, and 5 (about 5.4%) of them have the high activities with the ID₅₀≤1:200.The strain NCY2 was identified by morphological and molecule biological methods to be Xylaria sp. According to the results of bioactivity screening, TLC analysis and Phylogeny among the isolates, two strains namely NCY2 and TF5, were chosen for further chemical research. Seven new sesquiterpenoids (H19, H21, NC, H53, H41, H59, H60) and eight new polyketides (hp2, H63, H50-2, H51-1, H51-2, H48, H40, hp7), along with 6 known compounds were isolated from liquid still culture of strain NCY2. A new diterpene glucoside compound (T9) and 8 known compounds were isolated from the fermentation culture of the strain TF5 on agar medium.The antitumor and antimicrobial activities of the 16 new compounds were measured and they showed weak activities, the further researches on their bioactivities were valuable.The results of this study indicated that endophytic fungi from gymnosperm plants are important source of novel chemically compounds, they are precious resources with potential for exploitation new drugs.