Studies in the chemistry of erythrina alkaloid derivatives—III : Two isomers of 2,3,4,4a,5,6,7,7a,8,9,10,11-dodecahydro-2,10-dioxo-1H-benzo[d]naphthalene

Diketone 2,3,4,4a,5,6,7,7a,8,9,10,11-dodecahydro-2,10-dioxo-1H-benzo[d]-naphthalene prepared by annulation of N-(1-cyclohexenyl)pyrrolidine with vinyl methyl ketone, was found to consist of two stereoisomers. Theoretical dipole moments of these were calculated, and their structures were shown by moment dipole measurements to be cis A/B, cis A/C and trans A/B, cis A/C, respectively. The isomer trans A/B, cis A/B was converted into trans A/B, cis A/C dodecahydro-1H-benzo[d]naphthalene by the Wolff-Kishner reduction.     

Cytosporones O, P and Q from an endophytic Cytospora sp.

Cytosporones O, P and Q, together with the known compounds cytosporones B, C, D, E and dothiorelones A, B, C, and H were isolated from the ascomycete fungus Cytospora sp. during a chemotaxonomic study of fungal endophytes belonging to the related genera Cytospora and Phomopsis from Brazil. The structures were determined by NMR spectroscopy and mass spectrometry. With exception of cytosporones D, E, Q, and dothiorelone B, all compounds were consistently detected in the metabolite profiles of eight Cytospora isolates investigated; and were also produced by a distinct chemotype of Phomopsis.     

Chemical Characterization of Three Accessions of Brassica juncea L. Extracts from Different Plant Tissues

Indian mustard or Brassica juncea (B. juncea) is an oilseed plant used in many types of food (as mustard or IV range salad). It also has non-food uses (e.g., as green manure), and is a good model for phytoremediation of metals and pesticides. In recent years, it gained special attention due to its biological compounds and potential beneficial effects on human health. In this study, different tissues, namely leaves, stems, roots, and flowers of three accessions of B. juncea: ISCI 99 (Sample A), ISCI Top (Sample B), and “Broad-leaf” (Sample C) were analyzed by HPLC-PDA/ESI-MS/MS. Most polyphenols identified were bound to sugars and phenolic acids. Among the three cultivars, Sample A flowers turned were the richest ones, and the most abundant bioactive identified was represented by Isorhamnetin 3,7-diglucoside (683.62 µg/100 mg dry weight (DW) in Sample A, 433.65 µg/100 mg DW in Sample B, and 644.43 µg/100 mg DW in Sample C). In addition, the most complex samples, viz. leaves were analyzed by GC-FID/MS. The major volatile constituents of B. juncea L. leaves extract in the three cultivars were benzenepropanenitrile (34.94% in Sample B, 8.16% in Sample A, 6.24% in Sample C), followed by benzofuranone (8.54% in Sample A, 6.32% in Sample C, 3.64% in Sample B), and phytone (3.77% in Sample B, 2.85% in Sample A, 1.01% in Sample C). The overall evaluation of different tissues from three B. juncea accessions, through chemical analysis of the volatile and non-volatile compounds, can be advantageously taken into consideration for future use as dietary supplements and nutraceuticals in food matrices.     

epi-Aszonalenins A, B, and C from Aspergillus novofumigatus

Three new benzodiazepines have been isolated from an unusual chemotype of Aspergillus novofumigatus: epi-aszonalenins A, B, and C. The structures were elucidated by use of one- and two-dimensional NMR spectroscopic techniques and HR ESI MS. The relative configuration was established on the basis of a single crystal X-ray diffraction study of epi-aszonalenin A and the absolute configuration was determined by optical rotation comparison with the literature data. The absolute configurations of epi-aszonalenins B and C were determined by circular dichroism comparison to epi-aszonalenin A.     

Electrospray Ionization-Induced Protein Unfolding

Electrospray ionization mass spectrometry (ESI-MS) measurements were performed under a variety of solution conditions on a highly acidic sub-fragment (B3C) of the C-terminal carbohydrate-binding repeat region of Clostridium difficile toxin B, and two mutants (B4A and B4B) containing fewer acidic residues. ESI-MS measurements performed in negative ion mode on aqueous ammonium acetate solutions of B3C at low ionic strength (I?<?80?mM) revealed evidence, based on the measured charge state distribution, of protein unfolding. In contrast, no evidence of unfolding was detected from ESI-MS measurements made in positive ion mode at low I or in either mode at higher I. The results of proton nuclear magnetic resonance and circular dichroism spectroscopy measurements and gel filtration chromatography performed on solutions of B3C under low and high I conditions suggest that the protein exists predominantly in a folded state in neutral aqueous solutions with I?>?10?mM. The results of ESI-MS measurements performed on B3C in a series of solutions with high I at pH 5 to 9 rule out the possibility that the structural changes are related to ESI-induced changes in pH. It is proposed that unfolding of B3C, observed in negative mode for solutions with low I, occurs during the ESI process and arises due to Coulombic repulsion between the negatively charged residues and liquid/droplet surface charge. ESI-MS measurements performed in negative ion mode on B4A and B4B also reveal a shift to higher charge states at low I but the magnitude of the changes are smaller than observed for B3C.     

Relationship between Neuroprotective Effects and Structure of Procyanidins

This study evaluated the relationship between the neuroprotective effects of procyanidins and their structural characteristics. In vitro, a rat pheochromocytoma cell line (PC12) was exposed to the grape seed-derived procyanidin monomers: catechin (C), epicatechin (EC), and epicatechin gallate (ECG); the procyanidin dimers: procyanidin B1 (B1), procyanidin B2 (B2), procyanidin B3 (B3), procyanidin B4 (B4), procyanidin B1-3-O-gallate (B1-G), and procyanidin B2-3-O-gallate (B2-G); and the procyanidin trimers: procyanidin C1 (C1) and N-acetyl-l-cysteine (NAC) for 24 h. Cells were then incubated with 200 μM H₂O₂ for 24 h. In vivo, zebrafish larvae (AB strain) 3 days post-fertilization were incubated with NAC or procyanidins (C, EC, ECG, B1, B2, B3, B4, B1-G, B2-G, C1) in 300 µM H₂O₂ for 4 days. Different grape seed procyanidins increased the survival of PC12 cells challenged with H₂O₂, improved the movement behavior disorder of zebrafish caused by H₂O₂, inhibited the increase of ROS and MDA and the decrease of GSH-Px, CAT, and SOD activities, and up-regulated the Nrf2/ARE pathway. The neuroprotective effects of the procyanidin trimer C1 treatment group were greater than the other treatment groups. These results suggest that the neuroprotective effect of procyanidins is positively correlated with their degree of polymerization.     

Thermal methods for evaluating polymorphic transitions in nifedipine

The thermal behaviour of nifedipine was studied with the view to understand the various phase transitions between its polymorphs. The focus was on polymorph identification, accompanying morphological changes during crystallization and the nature of the phase transformations. These features were compared to the complexity of the crystallization mechanisms, studied by dynamic differential scanning calorimetry (DSC) heating techniques. DSC, thermogravimetry (TG) established the temperature limits for preparation of amorphous nifedipine from the melt. DSC studies identified that metastable form B, melting point ∼163 °C, was enantiotropically related to a third modification, form C, which existed at lower temperatures. Form C converted endothermically to form B at ∼56 °C on heating and was shown by hot stage microscopy (HSM) to be accompanied by morphological changes. Modulated temperature differential scanning calorimetry (MTDSC) showed discontinuities in the reversing heat flow signal during crystallization of amorphous nifedipine (from ∼92 °C) to form B, which suggested that a number of polymorphs may nucleate from the melt prior to form B formation. Identification of the number of nifedipine polymorphs included the use of combined DSC-powder X-ray diffraction (PXRD) and variable temperature powder X-ray diffraction (VTPXRD). The crystallization kinetics studied by dynamic DSC heating techniques followed by analysis using the Friedman isoconversion method where values of activation energy (E) and frequency factor (A) were estimated as a function of alpha or extent of conversion (α). The variations in E with α, from 0.05 to 0.9, for the amorphous to form B conversion could indicate the formation of intermediate polymorphs prior to form B. The form B to form A conversion showed a constancy in E on kinetic analysis from α 0.05 to 0.9, which suggested that a constant crystallization mechanism operated during formation of the thermodynamically stable form A.     

Effect of ethanediamine on bio-polishing of cotton fabrics with cellulase

n-Propylamine and n-butylamine showed an inhibitory effect on cellulase A and cellulase B, while ethanediamine displayed a positive effect on both of these cellulases. Relative filter paper activity and relative CMCase activity of cellulase A and cellulase B measured at 50 °C were increased by 16.0 and 25.2 %, and 18.9 and 13.9 %, respectively, by the appearance of ethanediamine at a certain concentration. Also the addition of ethanediamine maintained the thermal stability of cellulase A and B at 65 °C to some extent and showed a stronger stabilizing effect on cellulase A than cellulase B. Third, the addition of ethanediamine within a certain concentration range enhanced the bio-polishing effect of cotton fabric enzymatic treatment at 50 °C to some extent, obtaining a close bio-polishing effect of cotton fabrics treated at 50 °C; the addition of ethanediamine saved some of the dose of cellulase A and B. Last but not least, the appearance of ethanediamine broadened the operating temperature of cellulase A to 65 °C, and it had a less positive effect on cellulase B at 65 °C.     

Effects and Economic Sustainability of Biochar Application on Corn Production in a Mediterranean Climate

The effects of two types of biochar on corn production in the Mediterranean climate during the growing season were analyzed. The two types of biochar were obtained from pyrolysis of Pinus pinaster. B1 was fully pyrolyzed with 55.90% organic carbon, and B2 was medium pyrolyzed with 23.50% organic carbon. B1 and B2 were supplemented in the soil of 20 plots (1 m²) at a dose of 4 kg/m². C1 and C2 (10 plots each) served as control plots. The plots were automatically irrigated and fertilizer was not applied. The B1-supplemented plots exhibited a significant 84.58% increase in dry corn production per square meter and a 93.16% increase in corn wet weight (p << 0.001). Corn production was no different between B2-supplemented, C1, and C2 plots (p > 0.01). The weight of cobs from B1-supplemented plots was 62.3%, which was significantly higher than that of cobs from C1 and C2 plots (p < 0.01). The grain weight increased significantly by 23% in B1-supplemented plots (p < 0.01) and there were no differences between B2-supplemented, C1, and C2 plots. At the end of the treatment, the soil of the B1-supplemented plots exhibited increased levels of sulfate, nitrate, magnesium, conductivity, and saturation percentage. Based on these results, the economic sustainability of this application in agriculture was studied at a standard price of €190 per ton of biochar. Amortization of this investment can be achieved in 5.52 years according to this cost. Considering the fertilizer cost savings of 50% and the water cost savings of 25%, the amortization can be achieved in 4.15 years. If the price of biochar could be reduced through the CO₂ emission market at €30 per ton of non-emitted CO₂, the amortization can be achieved in 2.80 years. Biochar markedly improves corn production in the Mediterranean climate. However, the amortization time must be further reduced, and enhanced production must be guaranteed over the years with long term field trials so that the product is marketable or other high value-added crops must be identified.     

Volatolomics of Sardinian and Spanish Bituminaria: Characterization of Different Accessions Using Chemometrics

The present study aims to determine the volatile compositions of 15 different accessions of native Sardinian populations of Bituminaria morisiana (Pignatti & Metlesics) Greuter, Bituminaria bituminosa (L.) C. H. Stirt. (B. b.), and Spanish native accessions of B. bituminosa. Furthermore, we particularly focused on the essential oil characterization of these accessions and discriminated within populations with low furocoumarin content useful for fodder production in Mediterranean environments or furocoumarin extraction for pharmaceutical utilization. The plant extracts were analyzed by GC/MS, showing great variability in the content and composition. No differences were found in Bituminaria bituminosa (L.) C.H. Stirt. var. bituminosa essential oils, while the varieties Bituminaria bituminosa (L.) C.H. Stirt. var. crassiuscula P. Méndez, Fern. Galván & A. Santos and Bituminaria bituminosa (L.) C.H. Stirt. var. albomarginata P. Méndez, Fern. Galván & A. Santos are characterized by the presence of a high concentration of long-chain alcohols and of salicylic acid benzylic ester. In B. bituminosa var. albomarginata, we observed a different profile with predominance of a large concentration of alcohols as dodecanol and tetradecanol. The endemic B. morisiana can be identified for the predominant presence of farnesene. In methanolic fractions, we detected the presence of maltol, methyl citrate, methyl cumarate, santonin, and methyl linoleate. B. morisiana showed a low content of psoralens, and the accession of B. morisiana, from Siliqua indicated the presence of apocynin.     

Macrodasines A-G, macroline indole alkaloids incorporating fused spirocyclic tetrahydrofuran-tetrahydrofuran and tetrahydrofuran-tetrahydropyran rings

The bark extract of the Malayan Alstonia angustifolia Wall provided the spirocyclic alkaloids macrodasines A-G. The structures of the new compounds were established by analysis of the spectroscopic data and in the case of macrodasines A and B confirmed by X-ray diffraction analysis. Macrodasines A, B, C, and G incorporate fused spirocyclic tetrahydrofuran-tetrahydrofuran rings, while macrodasines D, E, and F incorporate fused tetrahydrofuran-tetrahydropyran rings. Macrodasines B, C, and E were found to show moderate levels of activity in reversing multidrug-resistance in drug-resistant KB cells.     

Enantioselective synthesis of chelidonine, a B/C-cis-11-hydroxyhexahydrobenzo[c]phenanthridine alkaloid

Both enantiomers of chelidonine, a B/C-cis-11-hydroxyhexahydrobenzo[c]phenanthridine alkaloid, were synthesized by manipulation of the B/C-dehydro ring juncture of benzo[c]phenanthridine skeleton using Sharpless asymmetric dihydroxylation and stereospecific catalytic hydrogenation after introduction of oxygen functions on the C ring as key reaction steps for the construction of stereogenic centers.     

Complete 1H and 13C NMR assignments for kanamycin A,kanamycin B and penta-N-acetyl-kanamycin B

The complete ¹H and ¹³C NMR assignments for kanamycin A, kanamycin B and penta-N-acetylkanamycin B were made by a combination of 1D- and 2D     

Enantioselective synthesis and stereochemical revision of communiols A-C

Enantioselective synthesis of the proposed structure of communiol C, an antibacterial tetrahydrofuran derivative produced by Podospora communis, and its stereoisomers revealed that the genuine stereochemistry of communiol C should be 3R, 5R, and 6S. Two other structurally related metabolites of the same microbial origin, communiols A and B, were also synthesized based on the revised stereochemistry.     

Polyfluorocycloalkenes. Part XIX. Some reactions and compounds from 1,2-bis(trifluoromethyl)octafluorocyclohexene

The title compound (A) gave a dichloro-adduct (D), which with lithium aluminum hydride yielded a complex mixture, from which a trace of trans 1H, 2H-1, 2-bis(trifluoromethyl)octafluorocyclohexane (E) was isolated. Catalytic hydrogenation of olefin (A) afforded cis 1H,2H-1,2-bis(trifluoromethyl)octafluorocyclohexane (C), and a small amount of 6H-1,6-bis(trifluoromethyl)heptafluorocyclohexene (B). Dehydrofluorination of the cis dihydride (C) by aqueous potash gave olefin (B) and 2,3-bis(trifluoromethyl)hexafluorocyclohexa-1,3-diene (G): fluorination of (G) by cobalt(III) fluoride gave back (A). Fluorination of compounds (C) and (B) afforded cis and trans 1H-1,2-bis(trifluoromethyl)nonafluorocyclohexane (J and H respectively). Both (H) and (J) were dehydrofluorinated to give olefin (A) exclusively, i.e. fluorine was lost preferentially from the tertiary →CF group. Ammonia and (A) gave 1,3-diamino-2-cyano-3-trifluoromethylhexafluorocyctohexene (K). Some hydro-polyfluoro-cyclohexanes took up small proportions of deuterium during dehydrofluorinations in the presence of deuterium oxide, but no interconversions of pairs of stereoisomers were observed.     

The stereoselective total syntheses of pectinolides A,B, and C

The stereoselective total synthesis of pectinolide B has been accomplished for the first time along with total syntheses of pectinolides A and C. MacMillan α-hydroxylation and Sharpless asymmetric dihydroxylation reactions are involved in generating the three stereogenic centers. Other important transformations in the synthesis are Z-selective Still–Gennari olefination, selective benzylation of the homoallylic alcohol, and a one-pot MOM deprotection followed by lactonization leading to all three pectinolides A–C being synthesized from a common intermediate. Pectinolides A, B, and C were synthesized from n-hexanal in 19, 20, and 18 steps with overall yields of 8.8%, 6.72%, and 9.2%, respectively.     

Purification and Biochemical Characterization of a Novel Thermo-stable Carboxymethyl Cellulase from Azorean Isolate Bacillus mycoides S122C

Bacillus mycoides S122C was identified as carboxymethyl cellulase (CMcellulase)-producing bacteria from the Azorean Bacillus collection (Lab collection), which was isolated from local soil samples. The bacteria was identified by 16S rRNA sequence and designated as B. mycoides S122C. NCBI blast analysis showed that the B. mycoides S122C 16S rRNA sequence has high identity compared to other B. mycoides strains. CMcellulase was purified from the culture filtrates using anion-exchange chromatography. After mono-Q purification, the protein folds and recovery were 13.7 and 0.76?%, respectively. SDS-PAGE analysis showed that the molecular weight of the purified CMcellulase protein was estimated to be about 62?kDa and that it was composed of a single subunit. MALDI-MS/MS analysis yielded each four peptides of the purified protein; it has identity to other cellulases. The purified CMcellulase showed high activity with CMcellulose followed by ??-glucan as a substrate. Optimum temperature and pH for the purified CMcellulase activity were found to be at 50?°C and pH?7.0, respectively. The purified CMcellulase was stable with about 60?% activity in broad pH ranges from 5 to 10 and temperature of 40 to 60?°C. However, purified CMcellulase was stable at about 70?% at 70?°C and also stable overall at 78?% for surfactants. CMcellulase activity was inhibited by ions such as HgCl₂, followed by CuSo₄, FeCl₂, and MnCl₂, while CoCl₂ activated CMcellulase activity. The purified CMcellulase activity was strongly inhibited by EDTA.     

Chemical Composition and Antifungal Activity of Myrcia multiflora and Eugenia florida Essential Oils

The essential oils of three specimens of Myrcia multiflora (A, B and C) and Eugenia florida were extracted by hydrodistillation, and the chemical compositions from the essential oils were identified by gas chromatography and flame ionization detection (CG/MS and CG-FID). The fungicide potential of the EOs against five fungicide yeasts was assessed: Candida albicans INCQS-40175, C. tropicalis ATCC 6258, C. famata ATCC 62894, C. krusei ATCC 13803 and C. auris IEC-01. The essential oil of the specimen Myrcia multiflora (A) was characterized by the major compounds: α-bulnesene (26.79%), pogostol (21.27%) and δ-amorphene (6.76%). The essential oil of the specimen M. multiflora (B) was rich in (E)-nerolidol (44.4%), (E)-γ-bisabolene (10.64%) and (E,E)-α-farnesene (8.19%), while (E)-nerolidol (92.21%) was the majority of the specimen M. multiflora (C). The sesquiterpenes seline-3,11-dien-6-α-ol (12.93%), eremoligenol (11%) and γ-elemene (10.70%) characterized the chemical profile of the EOs of E. florida. The fungal species were sensitive to the essential oil of M. multiflora (B) (9–11 mm), and the lowest inhibitory concentration (0.07%) was observed in the essential oil of M. multiflora (A) against the yeasts of C. famata. Fungicidal action was observed in the essential oils of M. multiflora (A) against C. famata, with an MIC of 0.78 µL/mL and 3.12 µL/mL; C. albicans, with an MFC of 50 µL/mL and M. multiflora (C) against C. albicans; and C. krusei, with a MFC of 50 µL/mL.