Núcleo de Bioensaios, Biossíntese e Ecofisiologia de Produtos Naturais (NuBBE), Departamento de Química Orgânica, Instituto de Química, UNESP - Universidade Estadual Paulista, 14801-970, Araraquara-SP, Brazil.
Departamento de Química, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos - UFSCar, 13565-905, São Carlos-SP, Brazil.
Sci Rep. 2019 Aug 23;9(1):12318. doi: 10.1038/s41598-019-48655-7.
A chemical study of the EtOAc extract of Nemania bipapillata (AT-05), an endophytic fungus isolated from the marine red alga Asparagopsis taxiformis - Falkenbergia stage, led to the isolation of five new botryane sesquiterpenes, including the diastereomeric pair (+)-(2R,4S,5R,8S)-(1) and (+)-(2R,4R,5R,8S)-4-deacetyl-5-hydroxy-botryenalol (2), (+)-(2R,4S,5R,8R)-4-deacetyl-botryenalol (3), one pair of diastereomeric botryane norsesquiterpenes bearing an unprecedented degraded carbon skeleton, (+)-(2R,4R,8R)-(4) and (+)-(2R,4S,8S)-(5), which were named nemenonediol A and nemenonediol B, respectively, in addition to the known 4β-acetoxy-9β,10β,15α-trihydroxyprobotrydial (6). Their structures were elucidated using 1D and 2D NMR, HRESIMS and comparison with literature data of similar known compounds. The absolute configurations of 2, 3 and 4 were deduced by comparison of experimental and calculated electronic circular dichroism (ECD) spectra, while those of 1 and 5 were assigned from vibrational circular dichroism (VCD) data. Compound 4 weakly inhibited acetylcholinesterase, whereas compound 1 inhibited both acetylcholinesterase and butyrylcholinesterase. Compounds 1, 3, 5 and 6 were tested against two carcinoma cell lines (MCF-7 and HCT-116), but showed no significant citotoxicity at tested concentrations (IC > 50 µM).
从海洋红藻 Asparagopsis taxiformis - Falkenbergia 阶段分离出的内生真菌 Nemania bipapillata (AT-05) 的 EtOAc 提取物的化学研究导致分离出五个新的 botryane 倍半萜，包括非对映异构体对 (+)-(2R,4S,5R,8S)-(1) 和 (+)-(2R,4R,5R,8S)-4-去乙酰基-5-羟基 botryenalol (2)、 (+)-(2R,4S,5R,8R)-4-去乙酰基 botryenalol (3)、一对具有前所未有的降解碳骨架的 botryane 降倍半萜非对映异构体， (+)-(2R,4R,8R)-(4) 和 (+)-(2R,4S,8S)-(5)，分别命名为 nemenonediol A 和 nemenonediol B，此外还有已知的 4β-乙酰氧基-9β,10β,15α-三羟基 probotrydial (6)。它们的结构通过 1D 和 2D NMR、HRESIMS 和与类似已知化合物的文献数据的比较来阐明。通过比较实验和计算的电子圆二色性 (ECD) 光谱，推断出 2、3 和 4 的绝对构型，而 1 和 5 的绝对构型则通过振动圆二色性 (VCD) 数据确定。化合物 4 对乙酰胆碱酯酶有弱抑制作用，而化合物 1 对乙酰胆碱酯酶和丁酰胆碱酯酶均有抑制作用。化合物 1、3、5 和 6 对两种癌细胞系 (MCF-7 和 HCT-116) 进行了测试，但在测试浓度下没有显示出显著的细胞毒性 (IC > 50 μM)。
