Khan Md Imdadul Huque, Sohrab Md Hossain, Rony Satyajit Roy, Tareq Fakir Shahidullah, Hasan Choudhury Mahmood, Mazid Md Abdul
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh.
BCSIR Laboratories Dhaka, Dr. Qudrat-I-Khuda Road, Dhanmondi, Dhaka 1205, Bangladesh.
Toxicol Rep. 2016 Oct 19;3:861-865. doi: 10.1016/j.toxrep.2016.10.005. eCollection 2016.
Endophytes have the potential to synthesize various bioactive secondary metabolites. The aim of the study was to find new cytotoxic and antibacterial metabolites from endophytic fungus, sp. isolated from the leaves of (L.) Benth. ex Kurz. (Fam: Apocyanaceae).
The endophytic fungus was grown on potato dextrose agar medium and extracted using ethyl acetate. Secondary metabolites were isolated by chromatographic separation and re-crystallization, and structures were confirmed by H NMR, C NMR and mass spectroscopic data. The cytotoxicity was determined by WST-1 assay and brine shrimp lethality bioassay, while antibacterial activity was assessed by disc diffusion method.
Two naphthoquinones, namely anhydrofusarubin () and methyl ether of fusarubin (2), were isolated from sp. The isolated compounds and by WST-1 assay against human leukemia cells (K-562) showed potential cytotoxicity with IC values of 3.97 μg/mL and 3.58 μg/mL, respectively. Initial screening of crude ethyl acetate extract and column fractions F-8 and F-10 exhibited noticeable cytotoxicity to brine shimp nauplii with LC values of 42.8, 1.2 and 2.1 μg/mL, respectively. Moreover, the isolated compound 2 (40 μg/disc) showed prominent activities against , , and with an average zone of inhibition of 27 mm, 25 mm, 24 mm and 22 mm, respectively and the activities were compared with kanamycin (30 μg/disc).
Our findings indicate that anhydrofusarubin () and methyl ether of fusarubin () might be useful lead compounds to develop potential cytotoxic and antimicrobial drugs.
内生菌有合成多种生物活性次生代谢产物的潜力。本研究的目的是从分离自长节珠（Apocynaceae科）叶片的内生真菌中寻找新的具有细胞毒性和抗菌活性的代谢产物。
将内生真菌接种于马铃薯葡萄糖琼脂培养基上，用乙酸乙酯提取。通过色谱分离和重结晶分离次生代谢产物，并用核磁共振氢谱（¹H NMR）、核磁共振碳谱（¹³C NMR）和质谱数据确定其结构。通过WST-1法和卤虫致死生物测定法测定细胞毒性，同时采用纸片扩散法评估抗菌活性。
从该内生真菌中分离得到两种萘醌，即脱水镰孢菌素（anhydrofusarubin）和镰孢菌素甲醚（methyl ether of fusarubin）。通过WST-1法测定分离得到的化合物对人白血病细胞（K-562）的细胞毒性，结果显示化合物1和2的半数抑制浓度（IC）值分别为3.97 μg/mL和3.58 μg/mL，具有潜在的细胞毒性。对粗乙酸乙酯提取物以及柱层析馏分F-8和F-10的初步筛选显示，它们对卤虫无节幼体具有明显的细胞毒性，LC值分别为42.8、1.2和2.1 μg/mL。此外，分离得到的化合物2（40 μg/纸片）对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌和铜绿假单胞菌均表现出显著活性，平均抑菌圈直径分别为27 mm、25 mm、24 mm和22 mm，并将其活性与卡那霉素（30 μg/纸片）进行比较。
我们的研究结果表明，脱水镰孢菌素（anhydrofusarubin）和镰孢菌素甲醚（methyl ether of fusarubin）可能是开发潜在细胞毒性和抗菌药物的有用先导化合物。
