綠藻源真菌株Acremonium tubakii NTU60之活性成分研究

Abstract

海洋環境複雜多變，具有豐富的真菌多樣性。本研究的藻體在基隆海科館附近沿岸採得，以進行藻源真菌的單離與菌株之抗菌活性篩選。其中，由腸石髮 (Ulva intestinalis) 所分離的頂孢黴菌 (Acremonium tubakii NTU60) 之粗萃物具有明顯的抑菌活性，因此在大量培養後，利用分離、純化技術找出具有活性的的次級代謝物。NTU60透過液態曝氣培養與固態糙米醱酵，進行化合物之分離、純化計獲得10個化合物。化合物Cephaibol A－C (1－3)、Cephaibol E (4)、Glycocholic acid (5)、Cholic acid (6)、Glycochenodeoxycholate (7)、Glycodeoxycholsaeure (8)、Helvolic acid (9) 與1-Linoleoyl glycerol (10)。在生物活性方面，Cephaibol A (1) 具有抑制新型隱球菌 (Cryptococcus neoformans) 的活性，其最小抑制濃度 (MIC) 為8 μg/mL；Cephaibol B (2) 與Helvolic acid (9) 抑制金黃色葡萄球菌 (Staphylococcus aureus) 的活性，其MIC分別為16 μg/mL與4 μg/mL；Cephaibol B (2) 對於人類抗藥性卵巢癌細胞 (Paclitaxel-resistant ovarian cancer cells, TOV-21G-RT) 與人類肝細胞癌細胞 (Hepatocellular carcinoma cells; SK-Hep-1) 細胞株具有毒殺活性，其半抑制濃度 (IC50) 分別為6.2 ± 0.1 μM與3.1 ± 0.5 μM；Cephaibol E (4) 在20 μM濃度下，沒有細胞毒性，卻對於小鼠小膠質細胞 (BV-2) 產生一氧化氮具有抑制活性，其效果為5.3 ± 1.5 μM。

The marine environment is extremely complex which contains a broad spectrum of fungal diversity. The algae of this study was collected from the seaboard near the National Museum of Marine Science and Technology, and the antimicrobial activity of the alga-derived fungi were screened. Among them, the crude extract of Acremonium tubakii NTU60, which was isolated from Ulva intestinalis, exibited significant antibacterial activity. In order to determine the best condition for enhancing chemical diversity, NTU60 were cultured in liquid- and solid-state fermentation. A series of separation and purification of the bioactive compound was thus carried out. Ten compounds, including cephaibols A－C (1－3), cephaibol E (4), glycocholic acid (5), cholic acid (6), glycochenodeoxycholate (7), glycodeoxycholsaeure (8), helvolic acid (9) and 1-Linoleoyl glycerol (10) were isolated from liquid- or solid-state fermented products of Acremonium tubakii NTU60. Cephaibol A (1) exhibited the activity of inhibiting Cryptococcus neoformans with a minimum inhibitory concentration (MIC) of 8 μg/mL, while Cephaibol B (2) and Helvolic acid (9) showed the activity of inhibiting Staphylococcus aureus with the MIC 16 μg/mL and 4 μg/mL, respectively. On the other hand, Cephaibol B (2) also showed cytotoxic activity against paclitaxel-resistant ovarian cancer cells (TOV-21G-RT) and hepatocellular carcinoma cells (SK-Hep-1), the half inhibitory concentrations (IC50) were 6.2 ± 0.1 μM and 3.1 ± 0.5 μM, respectively. Cephaibol E (4) showed the inhibitory effect on LPS-induced NO production murine brain microglial cell line (BV-2) with 5.3 ± 1.5 μM, without cytotoxic activity.