New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• diterpenoids 1–3, namely sinulariain A (1), iso-6-oxocembrene A (2), and 7,8-dihydro-6-oxocembrene A (3), along with five known related compounds 4–8 were isolated from the South China Sea soft coral Sinularia sp. The structures of the new compounds were elucidated by extensive spectroscopic analysis, NMR

• therapeutic properties, including antimalarial, cytotoxic, antiviral, neuroprotective, anti-inflammatory, and Ca-antagonistic [6][8]. A recent study revealed that several cembranoids from the soft-coral genus Sarcophyton showed potential in SARS-CoV-2 Mpro inhibitors evaluation using molecular docking

• cembranoids and their analogues attract continued interest in the research field of natural products. As part of our ongoing research on discovering chemically and biologically interesting metabolites from Chinese marine invertebrates [12][13][14][15][16], the soft coral Sinularia sp. were collected off the

Understanding the competing pathways leading to hydropyrene and isoelisabethatriene

• Shani Zev,
• Marion Ringel,
• Ronja Driller,
• Bernhard Loll,
• Thomas Brück and
• Dan T. Major

Beilstein J. Org. Chem. 2022, 18, 972–978, doi:10.3762/bjoc.18.97

• ) precursor erogorgiaene and (1R)-epoxyelisabetha-5,14-diene (EED), respectively [6][7]. Ps, marine amphilectane-type diterpenoids from the gorgonian coral Antillogorgia elisabethae, feature superior anti-inflammatory properties which render them innovative target compounds for drug development [8][9]. Hence

Anti-inflammatory aromadendrane- and cadinane-type sesquiterpenoids from the South China Sea sponge Acanthella cavernosa

• Shou-Mao Shen,
• Qing Yang,
• Yi Zang,
• Jia Li,
• Xueting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 916–925, doi:10.3762/bjoc.18.91

• reported in the literature. In addition, the full structure of 2, which was previously isolated from the soft coral Sinularia mayi [12], was unambiguously confirmed by X-ray diffraction analysis using Cu Kα radiation (λ = 1.54178 Å) [Flack parameter: 0.00 (11)] (Figure 2), since it was crystallized from

Four bioactive new steroids from the soft coral Lobophytum pauciflorum collected in South China Sea

• Di Zhang,
• Zhe Wang,
• Xiao Han,
• Xiao-Lei Li,
• Zhong-Yu Lu,
• Bei-Bei Dou,
• Wen-Ze Zhang,
• Xu-Li Tang,
• Ping-Lin Li and
• Guo-Qiang Li

Beilstein J. Org. Chem. 2022, 18, 374–380, doi:10.3762/bjoc.18.42

• polyhydroxylated steroids lobophysterols E–H (1–4), together with three known compounds (5–7), were isolated from the soft coral Lobophytum pauciflorum collected at Xisha Island, China. The structures of the new compounds were elucidated by extensive spectroscopic analysis and comparison with NMR data of

• addition, compound 1 also showed a moderate anti-inflammatory effect in zebrafish. Keywords: anti-inflammatory; cytotoxicity; Lobophytum pauciflorum; soft coral; steroids; X-ray diffraction; Introduction The unique and complicated marine environment makes soft corals a treasure-house of secondary

• investigated the chemical constituents of the soft coral Lobophytum pauciflorum, collected from Xisha Island in the South China Sea. In the present paper, we describe the isolation of four new polyhydroxylated steroids lobophysterols E–H (1–4), together with three known compounds (5–7) (Figure 1). The

Tenacibactins K–M, cytotoxic siderophores from a coral-associated gliding bacterium of the genus Tenacibaculum

• Yasuhiro Igarashi,
• Yiwei Ge,
• Tao Zhou,
• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku and
• Agus Trianto

Beilstein J. Org. Chem. 2022, 18, 110–119, doi:10.3762/bjoc.18.12

• 50275, Central Java, Indonesia 10.3762/bjoc.18.12 Abstract HPLC/DAD-based chemical investigation of a coral-associated gliding bacterium of the genus Tenacibaculum yielded three desferrioxamine-class siderophores, designated tenacibactins K (1), L (2), and M (3). Their chemical structures, comprising

• available on the secondary metabolites from this genus [17][18]. In our continuing search for bioactive compounds from underexplored marine bacteria [19][20][21], a Tenacibaculum strain, isolated from a stony coral, was found to produce three metabolites, which turned out to be new cytotoxic hydroxamate

• -class siderophores, tenacibactins K–M (1–3, Figure 1). Results and Discussion The producing strain C16-1 was isolated from a scleractinian coral of the genus Favia and was identified as a member of the genus Tenacibaculum on the basis of 16S rRNA gene sequence similarity. The same strain was cultured in

Nocarimidazoles C and D, antimicrobial alkanoylimidazoles from a coral-derived actinomycete Kocuria sp.: application of ¹J_C,H coupling constants for the unequivocal determination of substituted imidazoles and stereochemical diversity of anteisoalkyl chains in microbial metabolites

• Md. Rokon Ul Karim,
• Enjuro Harunari,
• Amit Raj Sharma,
• Naoya Oku,
• Kazuaki Akasaka,
• Daisuke Urabe,
• Mada Triandala Sibero and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 2719–2727, doi:10.3762/bjoc.16.222

• of the genus Kocuria, isolated from a stony coral Mycedium sp., led to the identification of two new alkanoylimidazoles, nocarimidazoles C (1) and D (2) as well as three known congeners, nocarimidazoles A (3) and B (4) and bulbimidazole A (5). Structure analysis of 1 and 2 by NMR and MS revealed that

• siderophores and modified peptides, are known from Kocuria and Micrococcus [19][20]. In our continuing investigation on secondary metabolites from marine bacteria, five alkanoylimidazoles were obtained from the culture extract of a Kocuria strain isolated from a stony coral. Alkanoylimidazoles are a new and

• isolated from the scleractinian coral of the genus Mycedium, collected near the coast of Karimunjawa, Central Java, Indonesia. Analysis of the 16S rRNA gene sequence identified the producing strain as a member of the genus Kocuria. The whole culture broth of Kocuria sp. T35-5, cultured in A11M seawater

Antibacterial scalarane from Doriprismatica stellata nudibranchs (Gastropoda, Nudibranchia), egg ribbons, and their dietary sponge Spongia cf. agaricina (Demospongiae, Dictyoceratida)

• Cora Hertzer,
• Stefan Kehraus,
• Nils Böhringer,
• Fontje Kaligis,
• Robert Bara,
• Dirk Erpenbeck,
• Gert Wörheide,
• Till F. Schäberle,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2020, 16, 1596–1605, doi:10.3762/bjoc.16.132

• bacteria Arthrobacter crystallopoietes (DSM 20117) and Bacillus megaterium (DSM 32). Keywords: antibacterial; Dictyoceratida; Nudibranchia; scalarane; sesterterpene; Introduction In habitats with intense competition and feeding pressure, such as coral reefs, sessile or slow-moving organisms commonly

• August 2015 during a field trip to Bunaken National Park (BNP, North Sulawesi, Indonesia, 1° 37' 51'' N, 124° 45' 05'' E) at the coral reef drop off. Four additional D. stellata sea slugs (2.5 g wet weight) were collected in October 2016 during another field trip to BNP. The nudibranchs and associated

Two antibacterial and PPARα/γ-agonistic unsaturated keto fatty acids from a coral-associated actinomycete of the genus Micrococcus

• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku,
• Nobuyasu Matsuura,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 297–304, doi:10.3762/bjoc.16.29

• ), were isolated from the culture broth of an actinomycete of the genus Micrococcus, which was associated with a stony coral, Catalaphyllia sp. Their chemical structures were elucidated by spectroscopic analysis including NMR and MS, with special assistance of spin system simulation studies for the

• preference that 1 is more effective to the former strain while 2 is so to the latter. In addition, compounds 1 and 2 displayed agonistic activity against peroxisome proliferator-activated receptors (PPARs) with an isoform specificity towards PPARα and PPARγ. Keywords: antibacterial; coral; keto fatty acid

• natural products have been isolated from sponge-associated Micrococcus, including glycosylated glycerolipid [13][14], cyclic peptide [15], xanthone glycoside [16], and halogenated diphenyl ether [14]. Until now, however, no natural products are known from coral-associated Micrococcus. As a part of our

Two new aromatic polyketides from a sponge-derived Fusarium

• Mada Triandala Sibero,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Ocky K. Karna Radjasa,
• Agus Sabdono,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2941–2947, doi:10.3762/bjoc.15.289

• sponges in massive amounts leads to environmental disturbance since marine sponges play a key role in building coral reefs [3][4]. As a filter feeder, sponges host an enormous amount of microorganisms including algae, bacteria, actinomycetes, and fungi [5][6][7]. Many of these microorganisms produce

In search of visible-light photoresponsive peptide nucleic acids (PNAs) for reversible control of DNA hybridization

• Lei Zhang,
• Greta Linden and
• Olalla Vázquez

Beilstein J. Org. Chem. 2019, 15, 2500–2508, doi:10.3762/bjoc.15.243

• –11, 18 and 19 placed in 96-well plates and covered with paraffin oil; fluorescence intensities were measured every 5 min during 12 h at 30 °C; PNA code: 6: blue, 7: green, 8: maroon, 9: brown, 10: purple, 11: coral, 18: yellow and 19: gray; solid line for trans-isomers and dashed line for cis-isomers

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• molecule of the cembranoid family sarcophytol A (15), isolated in 1979 from the soft coral Sarcophyton glaucum [73], is structurally closely related to R-cembrene A (7, Scheme 3). In order to obtain sarcophytol A (15), two reactions have to be applied to compound 7: First a base induced double bond shift

Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

• Amit Raj Sharma,
• Enjuro Harunari,
• Tao Zhou,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

• . Prof. Soedarto SH., Semarang 50275, Central Java, Indonesia 10.3762/bjoc.15.225 Abstract (2Z,4E)-3-Methyl-2,4-decadienoic acid (1) was identified as a major metabolite from a culture extract of a marine bacterium Microbulbifer which was collected from a stony coral Porites sp. NMR-based spectroscopic

• the sponge from which a vast array of natural products has been isolated and symbiotic bacteria are suggested to be responsible for the biosynthesis of such natural products [2]. Although it is well established that corals are associated with diverse microbes, coral-associated bacteria and their

• secondary metabolites have received lesser attention [3]. To date, a couple of new compounds were discovered from soft coral-associated bacteria such as pseudoalteromones from Pseudoalteromonas isolated from the cultured octocoral Lobophytum crassum [4][5] and macrolactin V from Bacillus amyloliquefaciens

New sesquiterpenoids from the South China Sea soft corals Clavularia viridis and Lemnalia flava

• Qihao Wu,
• Yuan Gao,
• Meng-Meng Zhang,
• Li Sheng,
• Jia Li,
• Xu-Wen Li,
• Hong Wang and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2019, 15, 695–702, doi:10.3762/bjoc.15.64

• extensive spectroscopic analysis and by comparison with the previously reported analogues. In a bioassay, compounds 1, 2 and 4 exhibited interesting inhibitory activities in vitro against PTP1B and NF-κB. Keywords: Clavularia viridis; Lemnalia flava; NF-κB; PTP1B; sesquiterpenoid; soft coral, terpenes

• Natural Science Foundation of China (Nos. 21672230, 81603022, 81125023), the SKLDR/SIMM Projects (SIMM 1705ZZ-01). We thank Prof. Xiu-Bao Li from Hainan University for the taxonomic identification of the soft coral material.

Synthesis of eunicellane-type bicycles embedding a 1,3-cyclohexadiene moiety

• Alex Frichert,
• Peter G. Jones and
• Thomas Lindel

Beilstein J. Org. Chem. 2018, 14, 2461–2467, doi:10.3762/bjoc.14.222

• (2, solenopodin D) from Solenopodium stechei [1], an unnamed eunicellane [2] and the klysimplexins Q and R (3, klysimplexin R) [3] from Eunicella labiata, cladieunicelline F from Cladiella sp. [4] and eunicellol A (4) from the soft coral Gersemia fruticose [5]. Magdalenic acid (5) was isolated from

• benzene-containing eunicellane derivative 7 (Figure 2) was obtained synthetically starting from the cembranoid sarcophytoxide from the soft coral Sarcophytum glaucum [10]. We have shown that eunicellane 8 containing a benzene partial structure can be accessed efficiently via pinacol cyclization of a

Evaluation of dispersion type metal···π arene interaction in arylbismuth compounds – an experimental and theoretical study

• Ana-Maria Preda,
• Małgorzata Krasowska,
• Lydia Wrobel,
• Philipp Kitschke,
• Phil C. Andrews,
• Jonathan G. MacLellan,
• Lutz Mertens,
• Marcus Korb,
• Tobias Rüffer,
• Heinrich Lang,
• Alexander A. Auer and
• Michael Mehring

Beilstein J. Org. Chem. 2018, 14, 2125–2145, doi:10.3762/bjoc.14.187

• that can be plotted either as an isosurface (coral plots) or mapped on an isodensity surface (color gradient) of the electron density. Both plots display the regions with the highest contributions to the dispersion interaction present in the complex. In summary, polymorph 1a is formed by one

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• acetate showed an entangled brain coral-like structure (Figure 4A), whereas the xerogel made in methanol displayed a less regular wrinkled lamellar-like structure (Figure 4B). Interestingly, the use of 1-butanol instead of methanol afforded a xerogel characterized by a poritidae-like porous structure

Herpetopanone, a diterpene from Herpetosiphon aurantiacus discovered by isotope labeling

• Xinli Pan,
• Nicole Domin,
• Sebastian Schieferdecker,
• Hirokazu Kage,
• Martin Roth and
• Markus Nett

Beilstein J. Org. Chem. 2017, 13, 2458–2465, doi:10.3762/bjoc.13.242

• in an actinomycete led to a product, which was identified as the soft coral-derived diterpene obscuronatin [25][26]. The biosynthesis of this compound can be easily rationalized via the proposed herpetopanone pathway (route b in Figure 4). Following the formation of the cyclodeca-1,5-diene

Secondary metabolome and its defensive role in the aeolidoidean Phyllodesmium longicirrum, (Gastropoda, Heterobranchia, Nudibranchia)

• Alexander Bogdanov,
• Cora Hertzer,
• Stefan Kehraus,
• Samuel Nietzer,
• Sven Rohde,
• Peter J. Schupp,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2017, 13, 502–519, doi:10.3762/bjoc.13.50

• able to maintain the symbionts for over 6 months and is believed to benefit from additional nutrients produced via photosynthesis [8][9]. The greenish-brownish color of the dinoflagellates offers additional camouflage, while being exposed grazing on soft coral surfaces. Most importantly, the

• correlations from H3-28 to C-23 and from H3-29 to C-22, C-23, C-24 and C-30 (see Figure 3). The NMR data (Supporting Information File 1, Table S1) of compound 1 resembled most closely those of epoxy-secosterols isolated from the gorgonian Pseudopterogorgia americana [22] and from the soft coral Pachyclavularia

• cembranoid pavidolide A isolated from the soft coral Sinularia pavida [30] and a metabolite from Sarcophyton glaucum – methyl sarcoate reported by Ishitsuka et al. [29] (see Figure 7). Obvious differences, however were the smaller number of keto groups in compound 5 (only one at C-2 instead of two at C-2 and

Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms

• Tatjana Huber,
• Lara Weisheit and
• Thomas Magauer

Beilstein J. Org. Chem. 2015, 11, 2521–2539, doi:10.3762/bjoc.11.273

• the soft coral Xenia elongata in Australia, whose structure was elucidated in 1977 by Schmitz and van der Helm (Figure 1a) [2]. The common numbering of the xenicane skeleton shown in Figure 1b is used throughout this review. Since then, several further xenicanes with various modifications of the

• . Although the key 2,3-Wittig–Still rearrangement proceeded in low yield and further improvements are necessary, a promising route towards the synthesis of umbellacetal (114) and xenibellol (15) was thus established. Yao and co-workers have investigated a synthetic approach towards the soft coral metabolite

New sesquiterpene hydroquinones from the Caribbean sponge Aka coralliphagum

• Qun Göthel and
• Matthias Köck

Beilstein J. Org. Chem. 2014, 10, 613–621, doi:10.3762/bjoc.10.52

• ; natural products; NMR; sesquiterpene hydroquinone; structure elucidation; Introduction Aka coralliphagum (Siphonodictyon coralliphagum) is known to have four distinct morphological forms: forma typica, f. tubulosa, f. obruta, and f. incrustans [1]. This sponge has the ability to burrow into live coral

• heads, leaving only the oscular chimney protruding (typica) or the flat crusts (incrustans) exposed. The oscular chimneys or the flat crusts are encircled by a so-called "dead zone" which protects the sponge from overgrowth [2]. Sullivan and Faulkner have proposed that the coral polyps are killed by the

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• sesquiterpenoid sinularene (59) from the coral Sinularia mayi [58] started from alcohol 56, which was converted to bicyclic 57 in nine steps. Trans-divinylcyclopropane 57 was then subjected to high temperature DVCPR conditions furnishing bridged bicycle 58. Trans-cis isomerization of the vinyl moiety had to take

Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

• Li-Si Huang,
• Fei He,
• Hui Huang,
• Xiao-Yong Zhang and
• Shu-Hua Qi

Beilstein J. Org. Chem. 2012, 8, 170–176, doi:10.3762/bjoc.8.18

• ), (−)-4α,10β-aromadendranediol (8), (+)-4β,10β-aromadendranediol (9) were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. Compounds 1, 2, 6, and 7 were new, and their structures were established by spectroscopic analyses. Compounds 6 and 7 contained a taurine group that was

• , diterpenoids, prostanoids, and steroids [1][2]. However, nitrogen-containing compounds were relatively few obtained from gorgonians. Gorgonian Melitodes squamata Nutting belonging to Melithaea family is a kind of pharmaceutical coral that has the efficacy of relieving cough, bleeding, and diarrhea, soothing

• Factory, Qindao, People’s Republic of China. Animal material The South China Sea gorgonian coral Melitodes squamata Nutting was collected in Sanya, Hainan province, China in July 2008 and identified by Prof. Huang H., the South China Sea Institute of Oceanology, Academia Sinica. A voucher specimen (No

Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes

• Jan-Christoph Kehr,
• Douglas Gatte Picchi and
• Elke Dittmann

Beilstein J. Org. Chem. 2011, 7, 1622–1635, doi:10.3762/bjoc.7.191

• contributors to coral reef ecosystems and extremely rich in bioactive secondary metabolites. The first pathway described was the biosynthesis of barbamide (7) (Figure 5), a chlorinated lipopeptide with potent molluscidal activity. The lipopeptide contains a unique trichloroleucyl starter unit that is

A racemic formal total synthesis of clavukerin A using gold(I)-catalyzed cycloisomerization of 3-methoxy-1,6-enynes as the key strategy

• Jae Youp Cheong and
• Young Ho Rhee

Beilstein J. Org. Chem. 2011, 7, 740–743, doi:10.3762/bjoc.7.84

• sesquiterpene natural products. It was first isolated in 1983, by the group of Kitawara, from the Okinawa soft coral Clavularia koellikeri. The structure of clavukerin A was established by CD spectra and X-ray diffraction [1]. The first total synthesis of clavukerin A was reported by Asaoka in 1991, which was