New mono- and dimeric members of the secalonic acid family:: Blennolides A-G isolated from the Fungus Blennoria sp.
New mono- and dimeric members of the secalonic acid family:: Blennolides A-G isolated from the Fungus Blennoria sp.
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DOI：
10.1002/chem.200800035
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发表时间：
2008-01-01
影响因子：
4.3
通讯作者：
Schulz, Barbara
中科院分区：
文献类型：
--
作者：
Zhang, Wen;Krohn, Karsten;Schulz, Barbara
Blennolides A-G（2-8）是7种不常见的色满酮类化合物，与Secalonic acid B（1）一起从Blennoria sp.来自Carpobrotits edidis的内生真菌。这是首次报道的blennolides 2和3（半癸酸B和E）的分离，其存在作为二聚体癸酸的单体单元已经很久了。拟定结构4的化合物（β-diversonolic酯）需要修订，因为其报告的数据不符合blennesterone C（4）的既定结构。其他单体，blennolides D-F（5-7）似乎是由blennolides A（2）和B（3）通过氢化芳环的重排而衍生的。异源二聚体8由单体blennestrin A（2）和重排的blennestrin E的11-脱羟基衍生物（6）组成，扩展了具有麦角黄质型骨架的麦角色素家族。新化合物的结构通过详细的光谱分析进行了阐明，并通过单晶的X-射线衍射研究进一步证实了2。绝对构型由CD光谱的TDDFT计算确定，包括固态CD/TDDFF方法。初步研究表明，这些化合物对紫色微孢菌和巨大芽孢杆菌分别具有较强的抗真菌和抗菌活性。它们也对细菌小球藻和大肠杆菌有活性。
Blennolides A-G (2-8), seven unusual chromanones, were isolated together with secalonic acid B (1) from Blennoria sp., an endophytic fungus from Carpobrotits edidis. This is the first reported isolation of the blennolides 2 and 3 (hemisecalonic acids B and E), the existence of which as the monomeric units of the dimeric secaIonic acids had long been postulated. A compound of the proposed structure 4 (beta-diversonolic ester) will need to be revised, as its reported data do not fit those of the established structure of blennolide C (4). Other monomers, the blennolides D-F (5-7) seem to be derived from blennolides A (2) and B (3) by rearrangement of the hydroaromatic ring. The heterodimer 8, composed of the monomeric blennolide A (2) and the rearranged 11-dehydroxy derivative of blennolide E (6), extends the ergochrome family with an ergoxanthin type of skeleton. The structures of the new compounds were elucidated by detailed spectroscopic analysis and further confirmed by an X-ray diffraction study of a single crystal of 2. The absolute configurations were determined by TDDFT calculations of CD spectra, including the solid-state CD/TDDFF approach. Preliminary studies showed strong antifungal and antibacterial activities of these compounds against Microbotryum violaceum and Bacillus megaterium, respectively. They were also active against the alga Chlorella fusca and the bacterium Escherichia coli.