α-Pyrone derivatives from the endolichenic fungus Nectria sp.

Five new α-pyrone derivatives, necpyrones A–E (1–5), together with seven known compounds (6–12), were isolated from the extract of an endolichenic fungus Nectria sp. Chemical structures of these compounds were elucidated by spectroscopic analyses (HRESIMS and NMR). The absolute configurations of C-6 in the pyrone ring as well as the chiral carbons at the aliphatic side chain resulted from hydroxyl substitute were finally determined on the basis of measurement of ECD and Kusumi–Mosher method.     

α-Pyrone derivatives with cytotoxic activities,from the endophytic fungus Phoma sp. YN02-P-3

Four new α-pyrone derivatives phomones C-F (1?4) together with four known compounds (5?8) were isolated from the endophytic fungus Phoma sp. YN02-P-3. Compound 1 is the first example of 6-α,β-unsaturated ester-2-pyrone dimers via intermolecular symmetrical [2 + 2] cycloaddition. The chemical structures of these compounds were determined from spectroscopic data (1D/2D NMR, MS and IR). The acetylated product (9) of 1 along with compounds 1–8 were then tested for their cytotoxicity against HL-60, PC-3 and HCT-116 cell lines. Compounds 2, 3, 5 and 9 with acetyl groups showed significant inhibitory activities against the three cell lines with IC₅₀ values in the range 0.52–9.85 μM. while compounds 1, 4 and 6–8 that possess no acetyl group showed no inhibitory activity (IC₅₀ > 50 μM), indicating that the acetyl group at 10- or 12- are essential for their cytotoxic activities. The structure-activity relationships of these phomones were also reported.     

Antifungal γ-Pyrone and Isoprenylated Cyclohexanoids from the Fungus Beenakia informis

Chemical investigation of the extract of the macroscopic fungus Beenakia informis led to the isolation of a previously unreported γ-pyrone and two new isoprenylated cyclohexanoids, together with speciocin N. Their structures were elucidated spectroscopically and the absolute configuration was determined by comparison of the experimental vs. calculated ECD curves. Three of the compounds showed very good to moderate activity against phytopathogenic fungi.     

Pestalofones A–E,bioactive cyclohexanone derivatives from the plant endophytic fungus Pestalotiopsis fici

Pestalofones A–E (1–5), five new cyclohexanone derivatives, have been isolated from cultures of the plant endophytic fungus Pestalotiopsis fici, along with the known compounds, isosulochrin (6), isosulochrin dehydrate (7), and iso-A82775C (8). The structures of 1–5 were determined by NMR spectroscopy, and the absolute configuration of 1 was assigned using the modified Mosher method. Compounds 1, 2, and 5 displayed inhibitory effects on HIV-1 replication in C8166 cells, whereas 3 and 5 showed significant antifungal activity against Aspergillus fumigatus.     

α-Glucosidase inhibition and antihyperglycemic activity of flavonoids from Ampelopsis grossedentata and the flavonoid derivatives

The dried leaves and stems of Ampelopsis grossedentata have been used as a health tea and herbal medicine for hundreds of years in China. The study was aimed at searching for novel α-glucosidase inhibitors among the richest components of A. grossedentata and their derivatives. Three known major components (1–3) were isolated by recrystallization process and six new derivatives (4–9) were obtained by etherification of the bioactive flavonoid. All compounds were evaluated for their inhibitory activities against α-glucosidase (from Saccharomyces cerevisiae). As a result, compound 9 showed a significant α-glucosidase inhibitory activity with IC₅₀ value of 9.3 μM and acted as a competitive inhibitor with the value of the inhibition constant (K_i) being 10.3 μM. The oral administration of compound 9 at a dose of 50 mg/kg significantly reduced the post prandial blood glucose levels of normal and streptozotocin (STZ)-induced diabetic mice. Furthermore, compound 9 significantly decreased the fasting blood glucose levels in STZ-induced diabetic mice.     

α-Santalol derivatives from Santalum album and their cytotoxic activities

A bioassay-guided fractionation of the heartwood of Santalum album led to the isolation of seven α-santalol derivatives including (9S,10E)-9-hydroxy-α-santalal, (10R,11S)-10,11-dihydroxy-α-santalol, (9E)-11,13-dihydroxy-α-santalol, and (10E)-12-hydroxy-α-santalic acid. Their structures were determined on the basis of results of spectroscopic analysis, including two-dimensional (2D) NMR spectroscopic data. The isolated compounds and derivatives were evaluated for cytotoxicity against HL-60 human promyelocytic leukemia cells and TIG-3 normal human diploid fibroblasts. Of these (9S,10E)-9-hydroxy-α-santalal, exhibited tumor-selective cytotoxicity. The apoptosis induction properties of sesquiterpenes with cytotoxic potency in HL-60 cells are also described.     

α-pyrone derivatives from endophytic fungus Diaporthe sp. RJ-41

A new α-pyrone derivative 1 and six known α-pyrone derivatives 2–7, along with known compounds 8–10 were isolated from the fermentation products of the endophytic fungus Diaporthe sp. RJ-41. Among them, nine compounds (1–9) were reported for the first time from the genus Diaporthe. This work expanded the knowledge of the chemical diversity of the genus Diaporthe, and the chemotaxonomic significance of the isolates was also discussed.     

α,α-trehalase from the brine shrimp Artemia salina. purification and properties

• 1.1. Trehalase (α,α-trehalose 1-d-glycohydrolase, E.C. 3.2.1.28) from cryptobiotic Artemia salina embryos was purified and characterized.
• 2.2. Most of the enzyme activity was present in an insoluble form and could be solubilized by deoxycholate treatment at high ionic strength and sonication.
• 3.3. The enzyme had a molecular weight of 75,000 and its isoelectric point was 6.2. It was optimally active at pH 5.6 with a K_m = 4.3 × 10⁻³ M for its natural substrate.
• 4.4. The enzyme was highly specific for trehalose, only lactose and cellobiose being hydrolyzed to a limited extent.

     

α-Isocedrene derivatives, 5-methyl coumarins and other constituents from the subtribe nassauviinae of the compositae

The investigation of four further representatives of the subtribe Nassauviinae afforded in addition to known compounds 17 α-isocedrene derivatives, four methyl coumarins, three methylchromones, three 1βH-guaiene derivatives and three nerolidol derivatives. The structures were elucidated by highfield NMR spectroscopy. The chemotaxonomy of the subtribe Nassauviinae is discussed briefly.     

New γ-pyranone and nucleoside derivatives from Penicillium sp.

Peniopyranone (1) and 2-methoxyl-β-l-Arabinofuroside uracil (2), together with six known compounds were isolated from the broth of Penicillium sp. (NO. 64). And their structures were established by comprehensive analysis of NMR, MS and CD spectra, the absolute configurations of Peniopyranone (1) were determined as 7S, 8S and 9R by calculating its ECD. The eight obtained metabolites were subjected to evaluate the preliminary cytotoxic activities to four cancer cell lines, but they showed no significant data with IC₅₀ > 50 μmol/mL. The results of acetylcholinesterase inhibiting assay showed that peniopyranone (1) displayed the inhibition activity to acetylcholinesterase with IC₅₀ at 15.2 μmol/mL.     

α-mannosidase and mannanase of some wood-rotting fungi

Cultivation media from 11 wood-rotting fungi contained α-mannosidase and mannanase activity. α-Mannosidase was studied in more detail inPhellinus abietis and mannanase was studied more intimately in basidiomycetesPhellinus abietis, Trametes sanguinea andPholiota aurivella. Suitable cultivation conditions and optimum conditions for the production of α-mannosidase and mannanase were determined. Both enzymes are constitutive; mannanase is extracellular, α-mannosidase was found in both mycelium and cultivation medium.     

Comparison of α-acetolactate synthase and α-acetolactate decarboxylase in Lactococcus spp. and Leuconostoc spp.

Summary Cell-free extracts of Leuconostoc and Lactococcus species were tested for their -acetolactate synthase and -acetolactate decarboxylase activities. In Leuconostoc mesenteroides subsp. cremoris, Leuconostoc mesenteroides subsp. mesenteroides and Leuconostoc lactis, the Km of -acetolactate synthase for pyruvate was close to 10 mM whereas it was 30 mM in Lactococcus lactis subsp. lactis biovar. diacetylactis. The Km of -acetolactate decarboxylase for -acetolactic acid was very low (0.3 mM) in Leuconostoc species in comparison to Lactococcus lactis subsp. lactis biovar. diacetylactis (60 mM). In the latter bacterium, -acetolactate decarboxylase showed a sigmoidal dependance upon -acetolactic acid and was activated by the three branchedchain amino acids: leucine, isoleucine and valine.     

The Production of β-Fructofuranosidase from Bifidobacterium spp.

The productions of β-fructofuranosidase from Bifidohacterium longum A1, B. adolescentis G1, and four other strains of Bifidobacteria were investigated. All strains used in this study were grown in modified BL broth containing a mixture of fructooligosaccharides [1^F (1-β-D-fructofuranosyl)_n-1sucrose, GF_n (n = 2 – 5)] as the only carbon source. Hydrolyses of 1-kestose, sucrose, and inulin were detected in the extract of the cell. The highest activity on 1-kestose was detected in the extract of B. longum A1 followed by B. adolescentis G1. The other extracts weakly attacked 1-kestose. The relative activities of the extract of B. adolescentis G1 for 1-kestose, nystose, 1^F-fructosylnystose, sucrose, and inulin were 100, 82.5, 50.8, 28.3, and 15.0, respectively. The relative activities for various substrates differed from invertases (yeast β-fructofuranosidases) and exo-inulinase from Penicillium trzehinskii.     

The ultrastructure of holdfasts, “rhizoids”, and “slime tracks” in thraustochytriaceous fungi and Labyrinthula spp.

Summary The fine structure of the holdfasts or rhizoids is described for the thraustochytriaceous organisms, Thraustochytrium motivum, Schizochytrium aggregatum, and an unidentified organism, denoted T-20, which resembles S. aggregatum and Labyrinthula spp. Labyrinthula algeriensis and L. minuta slime track ultrastructure is also described. The holdfasts, rhizoids, and tracks have the same basic fine structure and are collectively termed ectoplasmic nets. They are delimited by a unit membrane which is in continuity with the plasmalemma, contain no cytoplasmic organelles only membrane-limited cisternae, and contain a fibrogranular ground substance. The nets appear to arise from one or as many as 20 organelle complexes consist of an approximately disk-shaped electron-dense granular aggregate in which are embedded portions of cisternae of the endoplasmic reticulum or perinuclear clear continuum. The cisternae appear to contribute small (ca. 17 nm diameter) vesicles to the granular aggregate which coalesce to form internal membranes of the net elements. The sagenogenetosome underlies the plasmalemma where it evaginates to form the delimiting membrane of the main trunk element of the net. No continuous membrane separates the net contents from the cytoplasm, only the granular aggregate.In L. algeriensis, L. minuta, and T-20 the net is necessary for motility of nonflagellated, nonamoeboid cells. Presence of the nets is not associated with motility in S. aggregatum and T. motivum. The possible taxonomic significance of the observations is discussed.Contribution No. 456, Virginia Institute of Marine Science, Gloucester Point, Virginia 23062.Supported in part by the Oceanography Section, National Science Foundation, NSF Grant GA-31014.     

One new α-pyrone and one new fatty acid derivative from mangrove-derived fungus Phomopsis sp. HYP11

One new α-pyrone derivative (S)-3-(4-methoxy-3-methyl-2-oxo-2H-pyran-6-yl)butyl acetate (1) and one new fatty acid derivative (4S,5S)-5-acetoxy-4-hydroxyhexanoic acid (2), along with six known compounds (3–8) were obtained from the mangrove-derived fungus Phomopsis sp. HYP11. Their structures and absolute configurations were determined by detailed 1D and ²D NMR, HR-ESI-MS spectral, and quantum chemical electronic circular dichroism (ECD) calculations. Compounds 2, 3, 5, 6 and 8 showed antioxidant activity with the IC₅₀ values range of 0.09–0.67 mM, especially compounds 5 and 6 showed stronger antioxidant activity than the positive control trolox (IC₅₀ = 0.29 mM). Compound 8 showed weak antagonistic effect on Ralstonia solanacearum with the MIC value of 50 μg/mL.     

Interaction of A-nor A.19-dinor,and A-homo-5α-androstane derivatives with the androgen receptor and the epididymal androgen-binding protein

The equilibrium affinity constant for rat prostate androgen receptor and epididymal androgen binding protein (ABP) has been determined for thirty-four potential progestogens. Three A-nor-, four A,19-dinor-, and one A-homo-5α-androstane derivative bind to the androgen receptor (K_D<0.5 μM). Five of these compounds also bind to ABP with an affinity of the same order of magnitude. “Anordrin” (compound $\text{24}$) and “Dinordrins” (compounds $\text{10, 14, 15, 16, 17}$), which are potential female contraceptives, do not bind with high affinity to the androgen receptor or to ABP. The following modifications in A-nor derivatives favour binding to the receptor as compared to ABP: 19-nor substitution (compound $\text{1}$), C-18 methyl homologation (compound $\text{5}$), 2α-ethinylation (compound $\text{22}$). One 2α-allenyl A-nor derivative (compound $\text{25}$) and one A-homo derivative (compound $\text{34}$) bind almost exclusively to ABP. The interaction with either binding protein is decreased by oxidation or esterification of the hydroxyl group at C-17, and by addition of a 17 α-ethinyl group. The latter modifications are likely to increase the specificity of androstane derivatives for receptors other than androgen binding proteins, such as the progesterone receptor.     

Some foliicolous ectoparasites and associated fungi from Jabalpur (M.P.) — I

Summary The present paper describes nine ectoparasitic foliicolous fungi from Jabalpur (M.P.) India. These include four new species viz.Asterina woodfordiae Sahni onWoodfordia fruticosa (L.)Kurz.,Schiffnerula fici Sahni, onFicus infectoria Roxb.,Sarcihella fumosus Sahni onAegle marmelos Corr. andSarcinella odinae Sahni onOdina wodier Roxb.,Acremoniella sarcinellae Pat. &Har.,Fumago vagans Pers.,Stigmella palawanensis Syd. andSchiffnerula cassiae are new fungus records for this country.Mitteriella zizyphina Syd. has been recorded onZizyphus xylopyra Willd., for the first time from this state.Z. xylopyra is a new host record forM. zizyphina.     

Lanosterol 14α-demethylase. Similarity of the enzyme system from yeast and rat liver

The chemical synthesis of 24,25-dihydro[32-¹⁴C]lanosterol is described. The incubation of this material with a cell-free system from $\text{Saccharomvoes cerevisiae}$ or with a microsomal preparation from rat liver resulted in both cases in the release of [¹⁴C]formic acid. This result suggests that in the biosynthesis of ergosterol in yeast, as well as in that of cholesterol in higher animals, the 14α-methyl group of lanosterol is removed as formic acid. In both systems, the measurement of the rate of release of [¹⁴C]formic acid from 24,25-dihydro[32-¹⁴C]lanosterol provides a simple and direct assay of lanosterol 14α-demethylase. Carbon monoxide inhibited both yeast and liver 14α-demethylase.