New Spirotetronate Antibiotics, Lobophorins H and I, from a South China Sea-Derived Streptomyces sp. 12A35

Abstract

Strain 12A35 was isolated from a deep-sea sediment collected from the South China Sea and showed promising antibacterial activities. It was identified as Streptomyces sp. by the 16S rDNA sequence analysis. Bioassay-guided fractionation using HP20 adsorption, flash chromatography over silica gel and octadecylsilyl (ODS) and semi-preparative HPLC, led to the isolation and purification of five metabolites from the fermentation culture of 12A35. Two new spirotetronate antibiotics, lobophorins H (1) and I (2), along with three known analogues, O-β-kijanosyl-(1→17)-kijanolide (3), lobophorins B (4) and F (5) were characterized by 1D, 2D-NMR and MS data. These compounds exhibited significant inhibitory activities against Bacillus subtilis. Compounds 1 and 5 exhibited moderate activities against Staphylococcus aureus. In particular, the new compound lobophorin H (1) showed similar antibacterial activities against B. subtilis CMCC63501 to ampicillin.

Marine natural products

“…Ohmyungsamycins A 129 and B 130 inhibited growth of several HTCLs and of Gram-positive and Gram-negative bacteria with ohmyungsamycin A 129 being much more potent than B 130. 160 162 The polycyclic polyketide akaeolide 137 was isolated from a Streptomyces sp. (sediment, Miyazaki Harbour, Japan) as a modest cytotoxin to 3Y1 rat broblasts.…”

Extreme environments: microbiology leading to specialized metabolites

“…Chemical investigation of Marinactinospora thermotolerans, Streptomyces scopuliridis and Streptomyces drozdowiczii strains recovered from deep‐sea samples collected off South China (3865 m) led to the isolation of the cyclic peptides, marthiapeptide A ( 97 ), desotamide ( 98 ), desotamide B‐D ( 99 – 101 ) and marfomycins A–F ( 102 – 107 ) all of which showed antimicrobial activity against pathogenic Gram‐positive bacteria (Zhou et al , ; Song et al ). Additionally, three spirotetronate polyketides, lobophorin E ( 108 ), F ( 109 ) and H ( 110 ) extracted from two Streptomyces strains isolated from the same location at a depth of 2134 m, were shown to have antibacterial activity against a panel of Gram‐positive bacteria (Niu et al ; Pan et al ). Furthermore, a novel piezotolerant actinobacterium, Dermacoccus abyssi , isolated from Mariana Trench sediment produced novel phenazine metabolites, dermacozines A‐J ( 111–120 ); dermacozines F ( 116 ) and G ( 117 ) showed interesting antiproliferative activity towards the leukaemia cell line K562 with IC 50 values of 9 and 7 mmol l −1 (Abdel‐Mageed et al ; Wagner et al ).…”

Marine Pharmacology in 2012–2013: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis, and Antiviral Activities; Affecting the Immune and Nervous Systems, and Other Miscellaneous Mechanisms of Action

“…[53]; three new halogenated sesquiterpenes ( 40 – 42 ), isolated from the Chinese marine red alga Laurencia okamurai [54]; a new spirotetronate antibiotic, lobophorin H ( 43 ) from a South China Sea- Streptomyces sp. 12A35 [55]; a new cyclopeptide marthiapeptide A ( 44 ), isolated from the South China Sea-derived bacterium Marinactinospora thermotolerans [56]; two known napyradiomycin A1 ( 45 ) and napyradiomycin B3 ( 46 ) from a Chinese marine-derived Streptomyces sp. strain SCSIO [57,58]; two new hydroanthraquinone analogues 4a- epi -9α-methoxydihydrodeoxybostrycin ( 47 ) and 10-deoxy-bostrycin ( 48 ), isolated from a South China Sea marine-derived fungus Nigrospora sp., isolated from an unidentified sea anemone [59]; a novel cyclic peptide ohmyungsamycin A ( 49 ) from a Korean Streptomyces sp.…”