Geosmin (1) is a microbial terpene metabolite that is responsible for the typical smell of soil and causes an off-odor of food and water. Eudesmane sesquiterpenes are commonly found in plant essential oils. Here we describe the discovery of four geosmin-type metabolites, 7R-hydroxygeosmin (2), 3-oxogeosmin (3), 2R-hydroxy-7-oxogeosmin (4), 5-deoxy-7β,9β-dihydroxygeosmin (5), the plant-like eudesmanes 4β,10α-eudesmane-5β,11-diol (6) and (1S,5S,6S,7S,10S)-10α-eudesm-4(15)-ene-1α,6α-diol (7), and the known 1(10)E,5E-germacradiene-2,11-diol (8) from a bacterial endophyte (Streptomyces sp. JMRC:ST027706) of the mangrove plant Bruguiera gymnorrhiza. By means of NMR, MS, and ECD spectroscopy, all chemical structures as well as the absolute configurations for the new compounds were elucidated. Compounds 2–5 represent the first geosmin-related metabolites directly as bacterial natural products. The plant-derived eudesmane-5β,11-diol (6) and (1S,5S,6S,7S,10S)-10α-eudesm-4(15)-ene-1α,6α-diol (7) are also now reported as bacterial products. The broad antimicrobial activities of 6 against a suite of fungal and bacterial pathogens including methicillin-resistant Staphylococcus aureus suggest that this terpene could be an important active principle of the medicinal plant Cymbopogon distans. The discovery of geosmin metabolites from one actinomycete indicated that these bacteria could possess enzymes for modifying geosmin and offer a possibility for bioremediation.

中文翻译：

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来自细菌红树林内生菌的氧化土臭素和类植物 Eudesmanes。

土臭素 ( 1 ) 是一种微生物萜烯代谢物，它产生典型的土壤气味并导致食物和水的异味。Eudesmane倍半萜通常存在于植物精油中。在这里，我们描述了四个土臭味素型代谢物的发现，7 - [R -hydroxygeosmin（2），3- oxogeosmin（3），2 - [R羟基-7- oxogeosmin（4），5-脱氧7β，9β-dihydroxygeosmin（5 )，植物样eudesmanes 4β,10α-eudesmane-5β,11-diol ( 6 ) 和 (1 S ,5 S ,6 S ,7 S ,10 S )-10α-eudesm-4(15)-ene- 1α,6α-二醇 ( 7)，以及已知的 1(10) E ,5 E -germacradiene-2,11-diol ( 8 ) 来自红树林植物Bruguiera gemnorrhiza的细菌内生菌（Streptomyces sp. JMRC:ST027706）。通过 NMR、MS 和 ECD 光谱，阐明了新化合物的所有化学结构以及绝对构型。化合物2 – 5代表了第一种直接作为细菌天然产物的土臭素相关代谢物。植物来源的eudesmane-5β,11-diol ( 6 ) and (1 S ,5 S ,6 S ,7 S ,10 S )-10α-eudesm-4(15)-ene-1α,6α-diol (7 ) 现在也被报道为细菌产品。6对包括耐甲氧西林金黄色葡萄球菌在内的一系列真菌和细菌病原体的广泛抗菌活性表明，这种萜烯可能是药用植物Cymbopogon distans的重要活性成分。从一种放线菌中发现土臭素代谢物表明这些细菌可能拥有修饰土臭素的酶，并为生物修复提供了可能性。