Two New Cyclic Pentapeptides from the Marine‐Derived Fungus Aspergillus versicolor

Two new cyclic pentapeptides, named versicotides A ( 1 ) and B ( 2 ), were obtained from a marine‐derived fungus strain ZLN‐60, identified as Aspergillus versicolor. Their structures were established on the basis of chemical and spectroscopic evidence. Versicotides are new cyclic pentapeptides which contain an L ‐alanine residue, two anthranilic acid (=2‐aminobenzoic acid) residues, and two N‐methyl‐L ‐alanine residues. Antitumor activities were evaluated by the SRB and MTT methods.     

Benzodiazepine Alkaloids from Marine‐Derived Endophytic Fungus Aspergillus ochraceus

A new fungus‐derived benzodiazepine analogue, 2‐hydroxycircumdatin C ( 1 ), and a compound which has been isolated from a natural resource for the first time, but has been previously synthesized, namely (11aS)‐2,3‐dihydro‐7‐methoxy‐1H‐pyrrolo[2,1‐c][1,4]benzodiazepine‐5,11(10H,11aH)‐dione ( 2 ), along with five structurally related known alkaloids ( 3 – 7 ), were isolated from Aspergillus ochraceus, an endophytic fungus derived from the marine brown alga Sargassum kjellmanianum. Their structures were established on the basis of spectroscopic methods. The absolute configuration of 1 was determined through CD evidence. Compound 1 displayed significant DPPH radical‐scavenging activity with an IC₅₀ value of 9.9 μM , which is 8.9‐fold more potent than that of butylated hydroxytoluene (BHT), a well‐known synthetic positive control.     

Two New Secoanthraquinone Derivatives from the Marine‐Derived Endophytic Fungus Aspergillus wentii EN‐48

Two new secoanthraquinone derivatives, wentiquinones A ( 1 ) and B ( 2 ), together with the eight known compounds 3 – 10 , were isolated from the culture extracts of Aspergillus wentii EN‐48, an endophytic fungus derived from an unidentified marine brown algal species of the genus Sargassum. The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis.     

Sesterterpenes and 2H‐Pyran‐2‐ones (=α‐Pyrones) from the Mangrove‐Derived Endophytic Fungus Fusarium proliferatum MA‐84

Two new tricyclic sesterterpenes, fusaprolifins A and B ( 1 and 2 ), and three new 2H‐pyran‐2‐one derivatives, prolipyrones A – C ( 3 – 5 ), were isolated and characterized from Fusarium proliferatum MA‐84, an endophytic fungus obtained from the fresh tissue of the marine mangrove plant Bruguiera sexangula. In addition, two known sesterterpenes, terpestacin ( 6 ) and fusaproliferin ( 7 ), and one known 2H‐pyran‐2‐one derivative, gibepyrone D ( 8 ), were also identified. The structures of these compounds were elucidated by detailed spectroscopic analyses. Fusaprolifin A ( 1 ) showed moderate activity against brine shrimp (Artemia salina), with a lethality rate of 49.5% at 100 μg/ml, while fusaprolifin B ( 2 ) showed weak activity.     

Furanone Derivatives from Aspergillus sp. XW‐12, an Endophytic Fungus in Huperzia serrata

Two new 5‐methoxyfuran‐3(2H)‐one derivatives, huaspenone A ( 1 ) and B ( 2 ), together with four known ones, i.e., aspertetronin A ( 3 ), aspertetronin B ( 4 ), gregatin E ( 5 ), and penicilliol A ( 6 ), were isolated from the cultures of an endophytic fungus Aspergillus sp. XW‐12, derived from the stems of Huperzia serrata. The structures of the new isolates were established by detailed interpretation of the 1D‐ and 2D‐NMR and HR‐ESI‐MS data.     

Oxepine‐Containing Diketopiperazine Alkaloids from the Algal‐Derived Endophytic Fungus Paecilomyces variotii EN‐291

Two new oxepine‐containing diketopiperazine‐type alkaloids, varioloids A and B ( 1 and 2 , resp.), were isolated from the algal‐derived fungus Paecilomyces variotii EN‐291. The structures and absolute configurations were determined by detailed interpretation of 1D‐ and 2D‐NMR spectroscopic data and by analysis of acidic hydrolysates. Compounds 1 and 2 exhibited potent activity against the plant‐pathogenic fungus Fusarium graminearum with MIC values of 8 and 4 μg/ml, respectively.     

Structure and Absolute Configuration of Aspergilumamide A,a Novel Lumazine Peptide from the Mangrove‐Derived Fungus Aspergillus sp.

A novel lumazine peptide, aspergilumamide A ( 1 ), as well as a known analog penilumamide ( 2 ), were isolated from the mycelia of a marine‐derived fungus Aspergillus sp. (33241), obtained from the mangrove Bruguiera sexangula var. rhynchopetala collected from the South China Sea. The structure of 1 was identified by comprehensive spectroscopic analysis, including 1D‐ and 2D‐NMR, ESI‐MS, and MS/MS experiments. The absolute configuration of 1 was determined by Marfey's method.     

Ophiobolin Sesterterpenoids and Pyrrolidine Alkaloids from the Sponge‐Derived Fungus Aspergillus ustus

Chemical examination of the fungus Aspergillus ustus isolated from the Mediterranean sponge Suberites domuncula yielded the five new ophiobolin‐type sesterterpenoids 1 – 5 and the two new pyrrolidine alkaloids 6 and 7 , together with the known compound aurantiamine and cerebroside D. The structures of the new compounds were unambiguously elucidated on the basis of extensive spectroscopic‐data analysis (1D‐ and 2D‐NMR, MS, and UV) and comparison with literature data. All compounds were evaluated for their cytotoxicity against murine lymphoma cell line L5178Y.     

Two New Octahydronaphthalene Derivatives from Trichoderma spirale,an Endophytic Fungus Derived from Aquilaria sinensis

Two new octahydronaphthalene derivatives, trichodermic acid A ( 1 ) and trichodermic acid B ( 2 ), along with a known analog, trichodermic acid ( 3 ), and a known modified dipeptide, trichodermamide A ( 4 ), were isolated from the extract of Trichoderma spirale, an endophytic fungus present in the medicinal plant Aquilaria sinensis. The structures of these compounds were established by extensive analysis of their spectroscopic data including 1D‐ and 2D‐NMR and MS data.     

Two New Meroterpenes from the Mangrove Endophytic Fungus Aspergillus sp. 085241B

Two new meroterpenes, ‘acetoxydehydroaustin B’ ( 1 ) and ‘1,2‐dihydro‐acetoxydehydroaustin B’ ( 2 ) were isolated in the form of a mixed crystal from the mangrove endophytic fungus Aspergillus sp. 085241B. Their structures and absolute configurations were determined by extensive analysis of their spectra and X‐ray diffraction data. In a preliminary bioassay, the mixed crystal did not exhibit activities against cancer cell lines of MDA‐MB‐435, SKBR3, HepG2, HEP3B, PC‐3, and A549, as well as against α‐glucosidase and tyrosinase.     

Triazoles and Other N‐Containing Metabolites from the Marine‐Derived Endophytic Fungus Penicillium chrysogenum EN‐118

Two new triazoles, chrysotriazoles A and B ( 1 and 2 , resp.), along with two known quinazolinones, 3 and 4 , two known 2‐(4‐hydroxyphenyl)acetamides, 5 and 6 , and two known N‐(4‐hydroxystyryl)formamides, 7 and 8 , were isolated and identified from the culture extract of Penicillium chrysogenum EN‐118, an endophytic fungus obtained from the marine brown alga Sargassum pallidium. The structures of the isolated compounds were elucidated by NMR‐spectroscopic analysis, and that of compound 1 was confirmed by X‐ray crystallographic analysis of its p‐bromobenzoate derivative. Compounds 4, 5 , and 7 showed moderate cytotoxicities against Du145, A‐549, and HeLa cell lines.     

Two New Citrinin Dimers from a Volcano Ash‐Derived Fungus,Penicillium citrinum HGY1‐5

Two new citrinin dimers, penidicitrinin A ((2R,3S,5aS,9R,10S,12aR,12bR)‐2,3,5a,6,9,10,12a,12b‐octahydro‐7,12a‐dihydroxy‐12b‐methoxy‐2,3,4,9,10,11‐hexamethyl‐5H‐difuro[2,3‐b : 2′,3′‐h]xanthen‐5‐one; 1 ) and penidicitrinin B ((1S,3R,4S)‐1‐{2,6‐dihydroxy‐4‐[(1S,2R)‐2‐hydroxy‐1‐methylpropyl]‐3‐methylphenyl}‐3,4‐dihydro‐3,4,5‐trimethyl‐1H‐2‐benzopyran‐6,8‐diol; 2 ), together with three known citrinin monomers were isolated from a volcano ash‐derived fungus, Penicillium citrinum HGY1‐5. Their structures were established by spectroscopic methods, and they showed no cytotoxicity against two tumor cell lines.     

Alkaloid and Anthraquinone Derivatives Produced by the Marine‐Derived Endophytic Fungus Eurotium rubrum

Cultivation of the fungal strain Eurotium rubrum, an endophytic fungus that was isolated from the inner tissue of the semi‐mangrove plant Hibiscus tiliaceus, resulted in the isolation of one new dioxopiperazine alkaloid, 12‐demethyl‐12‐oxo‐eurotechinulin B ( 1 ), and one new anthraquinone derivative, 9‐dehydroxyeurotinone ( 2 ), together with ten known compounds including variecolorin J ( 3 ), eurotechinulin B ( 4 ), variecolorin G ( 5 ), alkaloid E‐7 ( 6 ), cryptoechinuline G ( 7 ), isoechinulin B ( 8 ), 7‐isopentenylcryptoechinuline D ( 9 ), 2‐O‐methyl‐9‐dehydroxyeurotinone ( 10 ), emodin ( 11 ), and emodic acid ( 12 ). The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data as well as by comparison with literature reports. Some of the purified compounds were evaluated for antibacterial, antifungal, and cytotoxic activities.     

Palmarumycins from the Endophytic Fungus Lasiodiplodia pseudotheobromae XSZ‐3

One new and three known spiro‐dioxynaphthalene compounds, related to palmarumycins, were isolated from the extracts of fungus Lasiodiplodia pseudotheobromae XSZ‐3. Their structures were established by spectroscopic methods (1D‐ and 2D‐NMR, HR‐ESI‐MS, etc.). The absolute configuration of 1 was determined by comparison of quantum‐chemical TDDFT (time‐dependent density‐functional theory) calculated and experimental ECD (electronic circular dichroism) spectra. The cytotoxic activities of 1 – 4 against HL‐60 cell line were evaluated by trypan blue‐staining assay.     

11‐ and 4′‐Epimers of Chaetomugilin A,Novel Cytostatic Metabolites from Marine Fish‐Derived Fungus Chaetomium globosum

11‐ and 4′‐epichaetomugilin A were isolated from a strain of Chaetomium globosum that was originally isolated from the marine fish Mugil cephalus. 11‐Epichaetomugilin A is the first compound to have an opposite absolute configuration at C(11) to that of other azaphilones isolated to date. Their absolute configurations were elucidated on the basis of spectroscopic analyses, including 1D‐ and 2D‐NMR techniques, and some chemical transformations. 11‐Epichaetomugilin A weakly inhibited the growth of cultured P388 cells and HL‐60 cells (IC₅₀ 88.9 and 66.7 μM , resp.).     

Diketopiperazine Alkaloids Produced by the Endophytic Fungus Aspergillus fumigatus from the Stem of Erythrophloeum fordii Oliv.

Four new diketopiperazine alkaloids, rel‐(8R)‐9‐hydroxy‐8‐methoxy‐18‐epi‐fumitremorgin C ( 1 ), rel‐(8S)‐19,20‐dihydro‐9,20‐dihydroxy‐8‐methoxy‐9,18‐di‐epi‐fumitremorgin C ( 2 ), rel‐(8S,19S)‐19,20‐dihydro‐9,19,20‐trihydroxy‐8‐methoxy‐9‐epi‐fumitremorgin C ( 3 ), and (3S,8S,9S,18S)‐8,9‐dihydroxyspirotryprostatin A ( 4 ), together with the eight known compounds 5 – 12 , were isolated from the endophytic fungus Aspergillus fumigatus. The structures of the new compounds were determined by extensive spectroscopic methods including HR‐ESI‐MS, NMR, and CD experiments. Compound 12 showed weak inhibitory activity in vitro against the release of β‐glucuronidase in rat polymorphonuclear leukocytes induced by the platelet‐activating factor. None of the twelve compounds exhibited detectable cytotoxic activities toward five human tumor cell lines (HCT‐8, Bel‐7402, BGC‐823, A549, and A2780) in the MTT assay.     

New Cytochalasins from the Marine‐Derived Fungus Xylaria sp. SCSIO 156

Two new cytochalasins, 18‐deoxycytochalasin Q ( 1 ) and 21‐O‐deacetylcytochalasin Q ( 2 ), together with four known analogues, cytochalasin Q ( 3 ), 19,20‐epoxycytochalasin Q ( 4 ), 21‐O‐deacetyl‐19,20‐epoxycytochalasin Q ( 5 ), and cytochalasin D ( 6 ), were isolated from the fungus Xylaria sp. SCSIO156 originated from the South China Sea marine sediment. The structures of 1 and 2 were elucidated by MS and 1D‐ and 2D‐NMR data analyses, and comparison with known compounds. The known compounds 3 – 6 were identified by comparison of their MS and NMR data with those reported in the literature. In the in vitro antitumor assay, compounds 2 – 6 showed mild cytotoxicity against three tumor cell lines (MCF‐7, SF‐268, and NCI‐H460).     

Oleanane‐Type Triterpenoids from the Endophytic Fungus Pestalotiopsis clavispora Isolated from the Chinese Mangrove Plant Bruguiera sexangula

Three new triterpenoid derivatives, named (15α)‐15‐hydroxysoyasapogenol B ( 1 ), (7β,15α)‐7,15‐dihydroxysoyasapogenol B ( 2 ), and (7β)‐7,29‐dihydroxysoyasapogenol B ( 3 ), were isolated from cultures of the plant endophytic fungus Pestalotiopsis clavispora. Their structures and relative configurations were elucidated by extensive spectroscopic analysis and X‐ray crystallography.     

Anthraquinone Derivatives and an Orsellinic Acid Ester from the Marine Alga‐Derived Endophytic Fungus Eurotium cristatum EN‐220

Cultivation of the fungal strain Eurotium cristatum EN‐220, an endophyte obtained from the marine alga Sargassum thunbergii, resulted in the isolation of one new anthraquinone glycoside, 3‐O‐(α‐D ‐ribofuranosyl)questinol ( 1 ) and one new orsellinic acid ester, cristatumside A ( 2 ), together with three known aromatic glycosides, 3‐O‐(α‐D ‐ribofuranosyl)questin ( 3 ), isotorachrysone 6‐O‐α‐D ‐ribofuranoside ( 4 ), and asperflavin ribofuranoside ( 5 ), as well as three anthraquinone derivatives, asperflavin ( 6 ), eurorubrin ( 7 ), and (+)‐variecolorquinone A ( 8 ). The structures of these compounds were determined by extensive analysis of their spectroscopic data, as well as by their comparison with those in the literature. Each of the isolated compounds was evaluated for its antimicrobial activity and brine shrimp lethality.