New potato micro-tuber-inducing cyclohexene compounds related to theobroxide from Lasiodiplodia theobromae.
Takei Ryo,Takahashi Kosaku,Matsuura Hideyuki,Nabeta Kensuke
Bioscience, biotechnology, and biochemistry
Two new cyclohexene compounds related to theobroxide (3) were isolated from the mycelia of Lasiodiplodia theobromae OCS71. The structures of these compounds were determined to be (4S,5S)-4,5-dihydroxy-2-methyl-cyclohex-2-enone (1) and (3aS,4R,5S,7aR)-4,5-dihydroxy-7-methyl-3a,4,5,7a-tetrahydrobenzo[1,3]dioxol-2-one (2) by means of spectroscopic analyses and chemical correlation to 3. Compound 2 was shown to take up the carbonate ion to form a carbonic acid ester non-enzymatically. The compounds also showed potato micro-tuber-inducing activities at a concentration of 10(-3) M, using a culture of single-node segments of potato stems in vitro.
Ambuic acid and torreyanic acid derivatives from the endolichenic fungus Pestalotiopsis sp.
Ding Gang,Li Yan,Fu Shaobin,Liu Shuchun,Wei Jiangchun,Che Yongsheng
Journal of natural products
Six new ambuic acid (1) derivatives (2-7) and a new torreyanic acid analogue (8) have been isolated from the crude extract of endophytic fungus Pestalotiopsis sp. inhabiting the lichen Multiclavula [corrected] sp. The structures of these compounds were elucidated primarily by NMR and MS methods, and their absolute configurations were assigned by application of the CD excitation chirality method. Compounds 1 and 2 displayed antimicrobial activity against the Gram-positive bacterium Staphylococcus aureus.
Quinone/hydroquinone meroterpenoids with antitubercular and cytotoxic activities produced by the sponge-derived fungus Gliomastix sp. ZSDS1-F7.
He Wei-Jun,Zhou Xiao-Jiang,Qin Xiao-Chu,Mai Yong-Xin,Lin Xiu-Ping,Liao Sheng-Rong,Yang Bin,Zhang Tianyu,Tu Zheng-Chao,Wang Jun-Feng,Liu Yonghong
Natural product research
Fifteen compounds, including six quinone/hydroquinone meroterpenoids, purpurogemutantin (1), macrophorin A (2), 4'-oxomacrophorin (3), 7-deacetoxyyanuthone A (4), 2,3-hydro-deacetoxyyanuthone A (5), 22-deacetylyanuthone A (6), anicequol (7), three roquefortine derivatives, roquefortine C (8), (16S)-hydroxyroquefortine C (9), (16R)-hydroxyroquefortine C (10), dihydroresorcylide (11), nectriapyrone (12), together with three fatty acid derivatives, methyl linoleate (13), phospholipase A (14), methyl elaidate (15), were isolated from the sponge-derived fungus Gliomastix sp. ZSDS1-F7 isolated from the sponge Phakellia fusca Thiele collected in the Yongxing island of Xisha. Their structures were elucidated mainly by extensive NMR spectroscopic and mass spectrometric analyses. Among these compounds, compounds 1-3 and 5-7 showed significant in vitro cytotoxicities against the K562, MCF-7, Hela, DU145, U937, H1975, SGC-7901, A549, MOLT-4 and HL60 cell lines, with IC values ranging from 0.19 to 35.4 μM. And compounds 2-4 exhibited antitubercular activity with IC values of 22.1, 2.44 and 17.5 μM, respectively. Furthermore, compound 7 had anti-enterovirus 71 activity with MIC value of 17.8 μM. To the best of our knowledge, this is the first report to product two quinone/hydroquinone meroterpenoids skeletons (linear skeleton and drimane skeleton) from the same fungal strain.
Chemical and bioactive natural products from Microthyriaceae sp., an endophytic fungus from a tropical grass.
Almeida C,Ortega H,Higginbotham S,Spadafora C,Arnold A E,Coley P D,Kursar T A,Gerwick W H,Cubilla-Rios L
Letters in applied microbiology
UNLABELLED:In screening for natural products with antiparasitic activity, an endophytic fungus, strain F2611, isolated from above-ground tissue of the tropical grass Paspalum conjugatum (Poaceae) in Panama, was chosen for bioactive principle elucidation. Cultivation on malt extract agar (MEA) followed by bioassay-guided chromatographic fractionation of the extract led to the isolation of the new polyketide integrasone B (1) and two known mycotoxins, sterigmatocystin (2) and secosterigmatocystin (3). Sterigmatocystin (2) was found to be the main antiparasitic compound in the fermentation extract of this fungus, possessing potent and selective antiparasitic activity against Trypanosoma cruzi, the cause of Chagas disease, with an IC50 value of 0.13 μmol l(-1) . Compounds 2 and 3 showed high cytotoxicity against Vero cells (IC50 of 0.06 and 0.97 μmol l(-1) , respectively). The new natural product integrasone B (1), which was co-purified from the active fractions, constitutes the second report of a natural product possessing an epoxyquinone with a lactone ring and exhibited no significant biological activity. Strain F2611 represents a previously undescribed taxon within the Microthyriaceae (Dothideomycetes, Ascomycota). SIGNIFICANCE AND IMPACT OF THE STUDY:The present study attributes new antiparasitic and psychoactive biological activities to sterigmatocystin (2), and describes the structure elucidation of the new natural product integrasone B (1), which possesses a rare epoxyquinone with a lactone ring moiety. This is also the first report of sterigmatocystin (2) isolation in a fungal strain from this family, broadening the taxonomic range of sterigmatocystin-producing fungi. The study also presents taxonomic analyses indicating that strain F2611 is strongly supported as a member of the Microthyriaceae (Ascomycota), but is not a member of any previously known or sequenced genus.
Isolation of bioactive steroids from the Stropharia rugosoannulata mushroom and absolute configuration of strophasterol B.
Wu Jing,Kobori Hajime,Kawaide Misaki,Suzuki Tomohiro,Choi Jae-Hoon,Yasuda Nobuhiro,Noguchi Keiichi,Matsumoto Tetsuo,Hirai Hirofumi,Kawagishi Hirokazu
Bioscience, biotechnology, and biochemistry
The absolute configuration of strophasterol B (1) isolated from the fruiting bodies of Stropharia rugosoannulata was determined by an X-ray crystallographic analysis. Three compounds (2 to 4) were isolated from the mushroom which suppressed or promoted lettuce growth.
Bioactive spirobisnaphthalenes from the endophytic fungus Berkleasmium sp.
Shan Tijiang,Tian Jin,Wang Xiaohan,Mou Yan,Mao Ziling,Lai Daowan,Dai Jungui,Peng Youliang,Zhou Ligang,Wang Mingan
Journal of natural products
Nine new spirobisnaphthalenes, palmarumycins B1-B9 (1-9), along with 13 known compounds (10-22), were isolated from cultures of the fungus Berkleasmium sp., an endophyte isolated from the medicinal plant Dioscorea zingiberensis C. H. Wright. The structures of the new compounds were elucidated by analysis of the 1D and 2D NMR and HRESIMS spectra and by comparison with known compounds. Compounds 7-9 contain an uncommon 2,3-dihydro-1H-inden-1-one unit. All isolated compounds were evaluated for their antibacterial activities against Bacillus subtilis, Staphylococcus hemolyticus, Agrobacterium tumefaciens, Pseudomonas lachrymans, Ralstonia solanacearum, and Xanthomonas vesicatoria and for their antifungal effects against the spore germination of Magnaporthe oryzae. Palmarumycin C8 (22) exhibited the best antibacterial and antifungal effects. In addition, diepoxin δ (11) and palmarumycin C8 (22) showed pronounced cytotoxic activities against five human cancer cell lines (HCT-8, Bel-7402, BGC-823, A 549, A 2780) with IC50 values of 1.28-5.83 μM.
Larvicidal spirobisnaphthalenes from the endophytic fungus Berkleasmium sp. against Aedes albopictus.
Tian Jin,Liu Xin Chao,Liu Zhi Long,Lai Daowan,Zhou Ligang
Pest management science
BACKGROUND:In our screening programme for new agrochemicals from endophytic fungi, the ethyl acetate extract of an endophytic Berkleasmium sp. isolated from the medicinal plant Dioscorea zingiberensis was found to possess strong larvicidal activity against the Asian tiger mosquito, Aedes albopictus. RESULTS:Bioassay-guided fractionation of the fungal extract has led to the isolation of seven spirobisnaphthalenes, including palmarumycins C8, C12, C15 and B6 and diepoxins γ, δ and ζ. Among them, palmarumycins C8 and B6 showed strong larvicidal activity against the fourth-instar larvae of A. albopictus, with LC50 values of 8.83 and 11.51 µg mL(-1) respectively. Interestingly, only spirobisnaphthalenes with a chlorine substituent possessed strong larvicidal activity. CONCLUSION:The results indicated that the spirobisnaphthalenes derived from the endophytic fungus Berkleasmium sp. could be promising leads for the development of new larvicides against A. albopictus.
Molecular basis of dimer formation during the biosynthesis of benzofluorene-containing atypical angucyclines.
Huang Chunshuai,Yang Chunfang,Zhang Wenjun,Zhang Liping,De Bidhan Chandra,Zhu Yiguang,Jiang Xiaodong,Fang Chunyan,Zhang Qingbo,Yuan Cheng-Shan,Liu Hung-Wen,Zhang Changsheng
Lomaiviticin A and difluostatin A are benzofluorene-containing aromatic polyketides in the atypical angucycline family. Although these dimeric compounds are potent antitumor agents, how nature constructs their complex structures remains poorly understood. Herein, we report the discovery of a number of fluostatin type dimeric aromatic polyketides with varied C-C and C-N coupling patterns. We also demonstrate that these dimers are not true secondary metabolites, but are instead derived from non-enzymatic deacylation of biosynthetic acyl fluostatins. The non-enzymatic deacylation proceeds via a transient quinone methide like intermediate which facilitates the subsequent C-C/C-N coupled dimerization. Characterization of this unusual property of acyl fluostatins explains how dimerization takes place, and suggests a strategy for the assembly of C-C and C-N coupled aromatic polyketide dimers. Additionally, a deacylase FlsH was identified which may help to prevent accumulation of toxic quinone methides by catalyzing hydrolysis of the acyl group.
Heterologous Expression of Fluostatin Gene Cluster Leads to a Bioactive Heterodimer.
Yang Chunfang,Huang Chunshuai,Zhang Wenjun,Zhu Yiguang,Zhang Changsheng
The biosynthesis gene cluster (fls) for atypical angucycline fluostatins was identified from the marine derived Micromonospora rosaria SCSIO N160 and was confirmed by gene knockouts and the biochemical characterization of a bifunctional oxygenase FlsO2. The absolute configuration of the key biosynthetic intermediate prejadomycin was determined for the first time by Cu Kα X-ray analysis. Heterologous expression of the intact fls-gene cluster in Streptomyces coelicolor YF11 in the presence of 3% sea salts led to the isolation of two new compounds: fluostatin L (1) and difluostatin A (2). Difluostatin A (2), an unusual heterodimer, exhibited antibacterial activities.
Biosynthesis of colabomycin E, a new manumycin-family metabolite, involves an unusual chain-length factor.
Petříčková Kateřina,Pospíšil Stanislav,Kuzma Marek,Tylová Tereza,Jágr Michal,Tomek Petr,Chroňáková Alica,Brabcová Eva,Anděra Ladislav,Krištůfek Václav,Petříček Miroslav
Chembiochem : a European journal of chemical biology
Colabomycin E is a new member of the manumycin-type metabolites produced by the strain Streptomyces aureus SOK1/5-04 and identified by genetic screening from a library of streptomycete strains. The structures of colabomycin E and accompanying congeners were resolved. The entire biosynthetic gene cluster was cloned and expressed in Streptomyces lividans. Bioinformatic analysis and mutagenic studies identified components of the biosynthetic pathway that are involved in the formation of both polyketide chains. Recombinant polyketide synthases (PKSs) assembled from the components of colabomycin E and asukamycin biosynthetic routes catalyzing the biosynthesis of "lower" carbon chains were constructed and expressed in S. aureus SOK1/5-04 ΔcolC11-14 deletion mutant. Analysis of the metabolites produced by recombinant strains provided evidence that in both biosynthetic pathways the length of the lower carbon chain is controlled by an unusual chain-length factor supporting biosynthesis either of a triketide in asukamycin or of a tetraketide in colabomycin E. Biological activity assays indicated that colabomycin E significantly inhibited IL-1β release from THP-1 cells and might thus potentially act as an anti-inflammatory agent.
Peniginsengins B⁻E, New Farnesylcyclohexenones from the Deep Sea-Derived Fungus sp. YPGA11.
Cheng Zhongbin,Xu Wei,Liu Lijun,Li Shumin,Yuan Wangjun,Luo Zhuhua,Zhang Jingjie,Cheng Yongjun,Li Qin
Chemical examination of the EtOAc extract of the deep sea-derived fungus sp YPGA11 resulted in the isolation of four new farnesylcyclohexenones, peniginsengins B⁻E (⁻), and a known analog peniginsengin A (). The structures of compounds ⁻ were determined on the basis of comprehensive analyses of the nuclear magnetic resonance (NMR) and mass spectroscopy (MS) data, and the absolute configurations of , , and were determined by comparisons of experimental electronic circular dichroism (ECD) with calculated ECD spectra. Compounds ⁻, characterized by a highly oxygenated 1-methylcyclohexene unit and a (4,8)-4,8-dimethyldeca-4,8-dienoic acid side chain, are rarely found in nature. Compounds ⁻ exhibited antibacterial activity against .
A new polyoxygenated farnesylcyclohexenone from Fungus Penicillium sp.
Yang Yabin,Yang Fangfang,Zhao Lixing,Duang Rongting,Chen Guangyi,Li Xiaozhan,Li Qiling,Qin Shaohuan,Ding Zhongtao
Natural product research
A new polyoxygenated farnesylcyclohexenone, peniginsengin A (1), was isolated from the fermentation of Penicillium sp. YIM PH30003, an endophytic fungus associated with Panax notoginseng (Burk.) F. H. Chen. The structure was assigned based on a combination of 1 D and 2 D NMR and mass spectral data. The cytotoxicity and antimicrobial activities of compound 1 were investigated.
Cytotoxic alkylated hydroquinone, phenol, and cyclohexenone derivatives from Aspergillus violaceofuscus Gasperini.
Myobatake Yusuke,Takemoto Kenji,Kamisuki Shinji,Inoue Natsuki,Takasaki Ayato,Takeuchi Toshifumi,Mizushina Yoshiyuki,Sugawara Fumio
Journal of natural products
New alkylated hydroquinones violaceoid A (1), violaceoid B (2), and violaceoid C (3), an alkylated phenol violaceoid D (4), and a cyclohexenoid violaceoid E (5) were isolated from a culture broth of Aspergillus violaceofuscus Gasperini isolated from moss. The structures were identified by interpretation of spectroscopic data (1D and 2D NMR, MS, and IR). Two known compounds, the cyclohexenoid 6 and eupenoxide (7), were also isolated. Compound 6 was isolated for the first time as a natural product and named violaceoid F. Isolated compounds were tested for cytotoxic activity against five human cancer cell lines and a mouse macrophage cell line. Violaceoid A was the most potent of the seven compounds against all cell lines. Violaceoid C and D exhibited cytotoxicity against the leukemia cell lines with LD50 values 5.9-8.3 μM, while violaceoid F was found to be cytotoxic against HCT116 and RAW264.7 with LD50 values of 6.4 and 6.5 μM, respectively. These results demonstrate that violaceoid derivatives are a new class of cytotoxic hydroquinones with a hydroxymethyl and a linear alkyl substituent.
A new compound from an endophytic fungus Alternaria tenuissima.
Wu Wen-Bin,Yue Gao-Chao,Huang Qi-Lin,Sun Ling-Ling,Zhang Wen
Journal of Asian natural products research
A new secondary metabolite, named altertoxin IV (1), together with altertoxin II (2), was isolated from the fermentation broth of Alternaria tenuissima, an endophytic fungal strain residing in the stem of Tribulus terrestris L. The structure of new compound 1 was established by HR-ESI-MS, multinuclear NMR spectroscopy, and single crystal X-ray diffraction method. In their in vitro bioassay, compound 2 exhibited moderate cytotoxic activity against PC-3 cell lines with an IC50 value of 14.28 μM.
Characterization of four new antifungal yanuthones from Aspergillus niger.
Petersen Lene M,Holm Dorte K,Knudsen Peter B,Nielsen Kristian F,Gotfredsen Charlotte H,Mortensen Uffe H,Larsen Thomas O
The Journal of antibiotics
Four new yanuthone analogs (1-4) were isolated from the filamentous fungus Aspergillus niger. The structures of the new compounds were elucidated on the basis of UHPLC-DAD-HRMS data and one-dimensional and two-dimensional NMR spectroscopy. Labeling studies with (13)C8-6-methylsalicylic acid identified three class I yanuthones originating from the polyketide 6-methylsalicylic acid (yanuthone K, L and M (1-3)) and a class II yanuthone, which was named yanuthone X2 (4). The four new compounds were tested toward the pathogenic yeast Candida albicans and all displayed antifungal activity. Yanuthone X2 represents the first example of a bioactive class II yanuthone, demonstrating the pharmaceutical potential of this class.
Effectors of thioredoxin reductase: Brevetoxins and manumycin-A.
Tuladhar Anupama,Hondal Robert J,Colon Ricardo,Hernandez Elyssa L,Rein Kathleen S
Comparative biochemistry and physiology. Toxicology & pharmacology : CBP
The activities of two effectors, brevetoxin (PbTx) and manumycin-A (Man-A), of thioredoxin reductase (TrxR) have been evaluated against a series of fourteen TrxR orthologs originating from mammals, insects and protists and several mutants. Man-A, a molecule with numerous electrophilic sites, forms a covalent adduct with most selenocystine (Sec)-containing TrxR enzymes. The evidence also demonstrates that Man-A can form covalent adducts with some non-Sec-containing enzymes. The activities of TrxR enzymes towards various substrates are moderated by Man-A either positively or negatively depending on the enzyme. In general, the reduction of substrates by Sec-containing TrxR is inhibited and NADPH oxidase activity is activated. For non-Sec-containing TrxR the effect of Man-A on the reduction of substrates is variable, but NADPH oxidase activity can be activated even in the absence of covalent modification of TrxR. The effect of PbTx is less pronounced. A smaller subset of enzymes is affected by PbTx. With a single exception, the activities of most of this subset are activated. Although both PbTx variants can react with selenocysteine, a stable covalent adduct is not formed with any of the TrxR enzymes. The key findings from this work are (i) the identification of an alternate mechanism of toxicity for the algal toxin brevetoxin (ii) the demonstration that covalent modification of TrxR is not a prerequisite for the activation of NADPH oxidase activity of TrxR and (iii) the identification of an inhibitor which can discriminate between cytosolic and mitochondrial TrxR.
New type II manumycins produced by Streptomyces nodosus ssp. asukaensis and their biosynthesis.
Hu Y,Floss H G
The Journal of antibiotics
Five new type II manumycins, containing the hydroxyquinol mC7N unit, asukamycins A-II, B-II, C-II, D-II, E-II, were discovered in cultures of Streptomyces nodosus ssp. asukaensis. The biosynthetic origin of the type II manumycins from the type I compounds, containing an epoxyquinol mC7N unit, was deduced from the time course of production and proven by preparing [7'-13C]asukamycin A and demonstrating its incorporation into asukamycin A-II.
Pestaloquinols A and B, isoprenylated epoxyquinols from Pestalotiopsis sp.
Ding Gang,Zhang Fan,Chen Hong,Guo Liangdong,Zou Zhongmei,Che Yongsheng
Journal of natural products
Two new isoprenylated epoxyquinol derivatives, pestaloquinols A (2) and B (3), and their putative biosynthetic precursor, cytosporin D (1), were isolated from the crude extract of the plant endophytic fungus Pestalotiopsis sp. The structures of these compounds were elucidated primarily by NMR experiments. Pestaloquinols A (2) and B (3) possess a previously undescribed nonacyclic ring system and showed cytotoxicity against HeLa cells.
Biosynthetic origins of the epoxyquinone skeleton in epoxyquinols A and B.
Fujita Katsuki,Ishikawa Fumihiro,Kakeya Hideaki
Journal of natural products
The biosynthetic origins of epoxyquinols A (1) and B (2) produced by an unidentified fungus have attracted considerable interest because these compounds could be assembled from a biosynthetic precursor, epoxycyclohexenone aldehyde (3), via an electrocyclization/intermolecular Diels-Alder dimerization cascade reaction. Furthermore, very little is known about the biosynthetic origins of naturally occurring epoxyquinone moieties. We herein describe the incorporation of (13)C at specific positions within the structure of a shunt product, epoxycyclohexenone (4), using stable isotope feeding experiments with sodium [1-(13)C]-acetate and sodium [1,2-(13)C2]-acetate. The results of these experiments strongly suggest that the epoxyquinone skeleton is assembled by a polyketide synthase.
Stereocontrolled synthesis of a complex library via elaboration of angular epoxyquinol scaffolds.
Lei Xiaoguang,Zaarur Nava,Sherman Michael Y,Porco John A
The Journal of organic chemistry
We have accomplished the synthesis of a complex chemical library via elaboration of angular epoxyquinol scaffolds with distinct skeletal frameworks. The key strategy involves highly stereocontrolled [4 + 2] Diels-Alder cycloadditions of chiral, nonracemic epoxyquinol dienes to generate the scaffolds. Further scaffold diversification involves hydrogenation, epimerization, dehydration, and condensation of the carbonyl group with alkoxyamine and carbazate building blocks. Further elaboration of the scaffolds also provided new skeletal frameworks using hydroxyl-directed Diels-Alder cycloaddition and reductive N-N bond cleavage. The overall process afforded 244 highly complex and functionalized compounds. Preliminary biological screening of the library uncovered six compounds which showed significant inhibition of Hsp 72 induction.
A new NF-κB inhibitor based on the amino-epoxyquinol core of DHMEQ.
Saitoh Tsuyoshi,Shimada Chika,Takeiri Masatoshi,Shiino Mitsuhiro,Ohba Shigeru,Obata Rika,Ishikawa Yuichi,Umezawa Kazuo,Nishiyama Shigeru
Bioorganic & medicinal chemistry letters
The amino-epoxyquinols 6a and 6b were synthesized as soluble derivatives of an NF-κB inhibitor DHMEQ (1). In spite of the opposite configuration from 1, 6b rather than 6a affected the deactivation of NF-κB, based on NO secretion and MALDI-TOF MS analysis. It was indicated that 6b inhibited the activation by different manner from that of 1.
Chemoenzymatic access to versatile epoxyquinol synthons.
Pinkerton David M,Banwell Martin G,Willis Anthony C
The enantiomerically pure and readily available metabolites 10-12 have been converted over four simple steps into the epoxyquinol derivatives 22-24, respectively. Compounds 23 and 24 or their immediate precursors have been exploited in efficient total syntheses of (-)-bromoxone (ent-1), (-)-epiepoformin (ent-2), (-)-harveynone (4), (+)-panepophenanthrin (6), and (+)-hexacyclinol (9).
Fungal metabolite, epoxyquinol B, crosslinks proteins by epoxy-thiol conjugation.
Kamiyama Hiroshi,Usui Takeo,Uramoto Masakazu,Takagi Hiroshi,Shoji Mitsuru,Hayashi Yujiro,Kakeya Hideaki,Osada Hiroyuki
The Journal of antibiotics
Epoxyquinol B (EPQB) is a fungal metabolite, containing two alpha,beta-epoxy ketones. We previously showed that EPQB inhibited the signal transduction involved in angiogenesis through the binding to cysteine residues of receptor kinases. However, the inhibitory mechanism was undefined. In this report, we found that one EPQB molecule is covalently bound to two L-cysteine molecules through two epoxide residues on EPQB. Furthermore, EPQB crosslinked binding proteins through the cysteine residues. These results suggest that EPQB inhibits receptor kinases by crosslinking with other protein or by intramolecular crosslinking.
Polyoxygenated Cyclohexenoids with Promising α-Glycosidase Inhibitory Activity Produced by Phomopsis sp. YE3250, an Endophytic Fungus Derived from Paeonia delavayi.
Huang Rong,Jiang Bo-Guang,Li Xiao-Nian,Wang Ya-Ting,Liu Si-Si,Zheng Kai-Xuan,He Jian,Wu Shao-Hua
Journal of agricultural and food chemistry
Seven new polyoxygenated cyclohexenoids, namely, phomopoxides A-G (1-7), were isolated from the fermentation broth extract of an endophytic fungal strain Phomopsis sp. YE3250 from the medicinal plant Paeonia delavayi Franch. The structures of these compounds were established by spectroscopic interpretation. The absolute configurations of compounds 1 and 4 were confirmed by X-ray crystallographic analysis and chemical derivative approach. All isolated compounds showed weak cytotoxic activities toward three human tumor cell lines (Hela, MCF-7, and NCI-H460) and weak antifungal activities against five pathogenic fungi (Candida albicans, Aspergillus niger, Pyricularia oryzae, Fusarium avenaceum, and Hormodendrum compactum). In addition, compounds 1-7 showed a promising α-glycosidase inhibitory activity with IC values of 1.47, 1.55, 1.83, 2.76, 2.88, 3.16, and 2.94 mM, respectively, as compared with a positive control of acarbose (IC = 1.22 mM).
A cyclic carbonate and related polyketides from a marine-derived fungus of the genus Phoma.
Liu Zimin,Jensen Paul R,Fenical William
Two metabolites, phomoxin and phomoxide, as well as the previously synthesized antibiotic eupenoxide, have been isolated from the fermentation broth of a marine-derived fungus of the genus Phoma (strain CNC-651). The new compounds are highly oxygenated polyketides of a new structural class. Phomoxin contains an unusual cyclic carbonate functionality that is rare among natural products. The structures of the new metabolites were assigned by spectroscopic methods that relied heavily on 2D NMR spectroscopic analysis.
Morphology regulatory metabolites from Arthrobotrys oligospora.
Zhang Hui-Xiang,Tan Jian-Lin,Wei Lu-Xia,Wang Yan-Li,Zhang Chuan-Ping,Wu De-Kai,Zhu Chun-Yan,Zhang Ying,Zhang Ke-Qin,Niu Xue-Mei
Journal of natural products
Novel autoregulatory metabolites, arthrosporols A-C (1-3), involved in regulating the morphological switch in fungi, were purified and characterized from the carnivorous fungus Arthrobotrys oligospora. These compounds possess a novel hybrid carbon skeleton consisting of an epoxy-cyclohexenol combined with a rare monocyclic sesquiterpenol substructure. This is the first report of a monocyclic sesquiterpenol of this type of fungal origin. Compounds 1-3 displayed significant inhibitory activities toward the formation of conidiophores, while compounds 1 and 3 showed the opposite effects on the formation of a two-dimensional network with increasing rates of 40-90% and inhibiting rates of 30-90%, respectively.
Fungal Highly Reducing Polyketide Synthases Biosynthesize Salicylaldehydes That Are Precursors to Epoxycyclohexenol Natural Products.
Liu Ling,Tang Man-Cheng,Tang Yi
Journal of the American Chemical Society
Fungal highly reducing polyketide synthases (HRPKSs) are highly programmed multidomain enzymes that synthesize reduced polyketide structures. Recent reports indicated salicylaldehydes are synthesized by HRPKS biosynthetic gene clusters, which are unexpected based on known enzymology of HRPKSs. Using genome mining of a HRPKS gene cluster that encodes a number of redox enzymes, we uncover the strategy used by HRPKS pathways in the biosynthesis of aromatic products such as salicylaldehyde , which can be oxidatively modified to the epoxycyclohexanol natural product trichoxide . We show selective β-hydroxyl groups in the linear HRPKS product are individually reoxidized to β-ketones by short-chain dehydrogenase/reductase enzymes, which enabled intramolecular aldol condensation and aromatization. Our work expands the chemical space of natural products accessible through HRPKS pathways.