Abstract

Five new α-pyrones, xylariaopyrones E–I (1–5), along with three known analogues (6–8) were isolated from the cultivation broth of the endophytic fungus Xylariales sp. (HM-1). The structures of the new compounds including their absolute configurations were elucidated by comprehensive spectroscopic methods and quantum ECD calculations. Xylariaopyrone E (1) is the first example of α-pyrone derivative with a novel [3, 2, 0] bridge ring system via a ketal function group in the side chain. In bioactivity assays, xylariaopyrones E–G (1–3) showed moderate inhibiting activities against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa with MIC values from 25.4 to 64.5 μg/mL, whereras xylariaopyrone G (3) exhibited significant inhibition of monoamine oxidase B with an IC₅₀ value of 15.6 μmol/L. Xylariaopyrone H (4) and the known compound 7 showed moderate toxicity against brine shrimp larvae with inhibition rates of 42.8% and 44.5%, respectively.

摘要

从内生真菌Xylariales sp.的培养液中分离出五种新的α-吡喃酮，即 xylariaopyrones E-I ( 1 – 5 ) 以及三种已知的类似物 ( 6 – 8 )。(HM-1)。通过综合光谱方法和量子ECD计算阐明了新化合物的结构，包括它们的绝对构型。Xylariaopyrone E ( 1 ) 是α-吡喃酮衍生物的第一个例子，它通过侧链中的缩酮官能团具有新颖的[3, 2, 0]桥环系统。在生物活性测定中，xylariaopyrones E–G ( 1 – 3) 对大肠杆菌、金黄色葡萄球菌和铜绿假单胞菌具有中等抑制活性，MIC 值为 25.4 至 64.5 μg/mL，而 xylariaopyrone G ( 3 ) 对单胺氧化酶 B 有显着抑制作用，IC ₅₀值为 15.6 μmol/L。Xylariaopyrone H ( 4 ) 和已知化合物7对盐水虾幼虫表现出中等毒性，抑制率分别为 42.8% 和 44.5%。