An anti-inflammatory isoflavone from soybean inoculated with a marine fungus Aspergillus terreus C23-3

A new isoflavone derivative compound 1 (psoralenone) was isolated from soybean inoculated with a marine fungus Aspergillus terreus C23-3, together with seven known compounds including isoflavones 2-6, butyrolactone I (7) and blumenol A (8). Their structures were elucidated by MS, NMR, and ECD. Psoralenone displayed moderate in vitro anti-inflammatory activity in the LPS-induced RAW264.7 cell model. Compound 2 (genistein) showed moderate acetylcholinesterase (AChE) inhibitory activity whereas compounds 2, 5 (biochanin A), 6 (psoralenol), and 7 exhibited potent larvicidal activity against brine shrimp. Compounds 3 (daidzein), 4 (4'-hydroxy-6,7-dimethoxyisoflavone), and 5-7 showed broad-spectrum anti-microbial activity, and compound 7 also showed moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity.

Altenusin derivatives from mangrove endophytic fungus Alternaria sp. SK6YW3L

Five new altenusin derivatives, compounds 1–5, along with six known analogues 6–11, were isolated from a culture of the endophytic fungus Alternaria sp. SK6YW3L, which was isolated from a fresh fruit of the mangrove plant Sonneratia caseolaris, collected from the South China Sea.

Polyketides with α-Glucosidase Inhibitory Activity from a Mangrove Endophytic Fungus, Penicillium sp. HN29-3B1

Five new compounds, pinazaphilones A and B (1, 2), two phenolic compounds (4, 5), and penicidone D (6), together with the known Sch 1385568 (3), (±)-penifupyrone (7), 3-O-methylfunicone (8), 5-methylbenzene-1,3-diol (9), and 2,4-dihydroxy-6-methylbenzoic acid (10) were obtained from the culture of the endophytic fungus Penicillium sp. HN29-3B1, which was isolated from a fresh branch of the mangrove plant Cerbera manghas collected from the South China Sea. Their structures were determined by analysis of 1D and 2D NMR and mass spectroscopic data. Structures of compounds 4 and 7 were further confirmed by a single-crystal X-ray diffraction experiment using Cu Kα radiation. The absolute configurations of compounds 1-3 were assigned by quantum chemical calculations of the electronic circular dichroic spectra. Compounds 2, 3, 5, and 7 inhibited α-glucosidase with IC50 values of 28.0, 16.6, 2.2, and 14.4 μM, respectively, and are thus more potent than the positive control, acarbose.

Bioactive Metabolites from Mangrove Endophytic Fungus Aspergillus sp. 16-5B

Chemical investigation of the endophytic fungus Aspergillus sp. 16-5B cultured on Czapek’s medium led to the isolation of four new metabolites, aspergifuranone (1), isocoumarin derivatives (±) 2 and (±) 3, and (R)-3-demethylpurpurester A (4), together with the known purpurester B (5) and pestaphthalides A (6). Their structures were determined by analysis of 1D and 2D NMR spectroscopic data. The absolute configuration of Compound 1 was determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra, and that of Compound 4 was revealed by comparing its optical rotation data and CD with those of the literature. The structure of Compound 6 was further confirmed by single-crystal X-ray diffraction experiment using CuKα radiation. All isolated compounds were evaluated for their α-glucosidase inhibitory activities, and Compound 1 showed significant inhibitory activity with IC₅₀ value of 9.05 ± 0.60 μM. Kinetic analysis showed that Compound 1 was a noncompetitive inhibitor of α-glucosidase. Compounds 2 and 6 exhibited moderate inhibitory activities.

Microbacterins A and B, new peptaibols from the deep sea actinomycete Microbacterium sediminis sp. nov. YLB-01(T)

Two new peptaibols, namely microbacterins A (1) and B (2), were isolated from the deep sea inhabited actinomycete Microbacterium sediminis spp. nov. YLB-01(T). The sequences of the amino acid residues were determined on the basis of intensive NMR and ESI-MS/MS spectroscopic analysis, in addition to the Marfey's method and CD and optical rotation data for the configurational assignment. Both 1 and 2 exhibited significant cytotoxic activities against a panel of human tumor cell lines.

Peniphenones A-D from the mangrove fungus Penicillium dipodomyicola HN4-3A as inhibitors of Mycobacterium tuberculosis phosphatase MptpB

A pair of unusual benzannulated 6,6-spiroketal enantiomers [(-)-1 and (+)-1] and three new biogenetically related compounds (2-4), together with two known related analogues (5 and 6), have been isolated from a mangrove fungus, Penicillium dipodomyicola HN4-3A. Their structures were elucidated on the basis of spectroscopic analysis (1D and 2D NMR data) and X-ray crystallography. The absolute configurations of enantiomers (-)-1 and (+)-1 were determined using quantum chemical calculations of the electronic circular dichroic (ECD) spectra. Compounds 2 and 3 exhibited strong inhibitory activity against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB) with IC50 values of 0.16±0.02 and 1.37±0.05 μM, respectively.

Xylariterpenoids A–D, four new sesquiterpenoids from the Xylariaceae fungus

Four new sesquiterpenoids, sesquiterpenoids A–D (1–4), were isolated from solid cultures of the Xylariaceae fungus (no. 63-19-7-3).

Three pairs of variecolortide enantiomers from Eurotium sp. with caspase-3 inhibitory activity

7-O-methylvariecolortide A (1), variecolortide B (2), and variecolortide C (3), the rare variecolortides existing in racemic manner, were isolated from an endolichenic fungal strain Eurotium sp. (No. 17-11-8-1). With the chiral HPLC technology, (-)-(S)-7-O-methylvariecolortide A (1a), (+)-(R)-7-O-methylvariecolortide A (1b), (-)-(S)-variecolortide B (2a), (+)-(R)-variecolortide B (2b), (-)-(S)-variecolortide C (3a), and (+)-(R)-variecolortide C (3b) were successfully separated and obtained. Their absolute configurations were firstly assigned by ECD experiment and ECD calculation. According to the relation of isolated compounds, a plausible biosynthetic pathway for variecolortides was proposed. In caspase-3 enzymatic assay, compounds 1-3 showed inhibitory activity, with IC50 values of 1.7, 0.8 and 15.7 μM, respectively.

Griseusins F and G, spiro-naphthoquinones from a tin mine tailings-derived alkalophilic Nocardiopsis species

Griseusins F (1) and G (2), two 2a-hydro-8a-(2-oxopropyl)-substituted spiro-naphthoquinones with a previously undescribed C23 polyketide skeleton, were isolated from a Yunnan tin mine tailings-derived alkalophilic actinomycete, Nocardiopsis sp. YIM DT266. Their complete structure assignments with the absolute stereochemistry were elucidated by spectroscopic data, X-ray crystal diffraction, calculation of optical rotation, and CD spectroscopic analysis. Compounds 1 and 2 exhibited strong cytotoxicity (IC50 0.37-0.82 μM) and antibacterial activity (MIC 0.80-1.65 μg/mL) against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) in vitro.

Sesquiterpenoids from Incarvillea arguta: absolute configuration and biological evaluation

Diincarvilones A-D (1-4), incarvilone A (5), and a known compound, argutosine B (6), were isolated from Incarvillea arguta. The structures, including the absolute configurations of the new compounds, were determined by NMR spectroscopy, X-ray diffraction analysis, CD spectroscopy, and a variety of computational methods. The biological properties of these substances, including effects on intracellular Ca(2+) influx, nitric oxide (NO) production, and human cancer cells, were evaluated. The results showed that at the concentration of 10 μM (in HBSS buffer) diincarvilones A and B cause a persistent increase in cytoplasmic calcium levels in A549 cells.

Guaiane-type sesquiterpenoid glucosides from Gardenia jasminoides Ellis

Two new guaiane-type sesquiterpenoid glucosides (1 and 2) were isolated from the fruit of Gardenia jasminoides Ellis. Their structures were elucidated to be (1R,7R,10S)-11-O-β-D-glucopyranosyl-4-guaien-3-one (1) and (1R,7R,10S)-7-hydroxy-11-O-β-D-glucopyranosyl-4-guaien-3-one (2) by one- and two-dimensional NMR techniques ((1)H NMR, (13)C NMR, HSQC, HMBC and NOESY), MS, CD spectrometry and chemical methods.

Stereumins H-J, stereumane-type sesquiterpenes from the fungus Stereum sp

Stereumins H (1), I (2), and J (3), three sesquiterpenes possessing a novel stereumane-type backbone, were isolated from an extract of culture broth of the Basidiomycete Stereum sp. CCTCC AF 207024. The complete structural assignments including the absolute configurations are reported by using X-ray studies and density functional theory at the B3LYP/aug-cc-pVDZ//B3LYP/6-31G(d) level.

Cytotoxic polyphenols from the marine-derived fungus Penicillium expansum

Two new polyphenols containing both phenolic bisabolane sesquiterpenoid and diphenyl ether units, expansols A (1) and B (2), and two new phenolic bisabolane sesquiterpenoids, (S)-(+)-11-dehydrosydonic acid (3) and (7S,11S)-(+)-12-acetoxysydonic acid (4), along with two known compounds, (S)-(+)-sydonic acid (5) and diorcinol (6), were isolated from the metabolites of the marine-derived fungus Penicillium expansum 091006 endogenous with the mangrove plant Excoecaria agallocha. On the basis of spectroscopic analysis, chemical transformation, and theoretical calculation, the structures of 1-4 were elucidated as (S)-(+)-2-[3-hydroxy-4-(2- methoxy-6-methylheptan-2-yl)benzyl]-5-(3-hydroxy-5-methylphenoxy)-3-methylphenol, S-(+)-2-[3-hydroxy-4-(2-hydroxy-6-methylheptan-2-yl)benzyl]-5-(3-hydroxy-5-methylphenoxy)-3-methylphenol, (S)-(+)-3-hydroxy-4-(2-hydroxy-6-methylhept-6-en-2-yl)benzoic acid, and 4-[(2S,6S)-7-acetoxy-2-hydroxy-6-methylheptan-2-yl]-3-hydroxybenzoic acid, respectively. Expansol A (1) exhibited moderate cytotoxicity against the HL-60 cell line with an IC(50) value of 15.7 microM, and expansol B (2) inhibited the proliferation of A549 and HL-60 cells with IC(50) values of 1.9 and 5.4 microM, respectively.

Time-dependent density functional response theory for electronic chiroptical properties of chiral molecules

Methodology to calculate electronic chiroptical properties from time-dependent density functional theory (TDDFT) is outlined. Applications of TDDFT to computations of electronic circular dichroism, optical rotation, and optical rotatory dispersion are reviewed. Emphasis is put on publications from 2005 to 2010, but much of the older literature is also cited and discussed. The determination of the absolute configuration of chiral molecules by combined measurements and computations is an important application of TDDFT chiroptical methods and discussed in some detail. Raman optical activity (ROA) spectra are obtained from normal-mode derivatives of the optical rotation tensor and other linear response tensors. A few selected (ROA) benchmarks are reviewed.