Cytotoxic and new tetralone derivatives from Berchemia floribunda (Wall.) Brongn

Two new alpha-tetralone (=3,4-dihydronaphthalen-1(2H)-one) derivatives, berchemiaside A and B (1 and 2, resp.), and one new flavonoid, quercetin-3-O-(2-acetyl-alpha-L-arabinofuranoside (3), together with ten known flavonoids compounds, eriodictyol (4), aromadendrin (5), trans-dihydroquercetin (6), cis-dihydroquercetin (7), kaempferol (8), kaempferol-3-O-alpha-L-arabinofuranoside (9), quercetin (10), quercetin-3-O-alpha-L-arabinofuranoside or avicularin (11), quercetin 3'-methyl ether, 3-O-alpha-L-arabinofuranoside (12), and maesopsin (13), were isolated from the bark of Berchemia floribunda. Their structures were determined by various NMR techniques and chemical studies. Compounds 3-13 were tested for their cytotoxic activity against human leukemia cells. Among them, kaempferol (8) and maesopsin (13) showed significant inhibitory activities against human leukemia cells CCRF-CEM and its multidrug-resistant sub-line, CEM/ADR5000, with IC(50) values of 14.0, 5.3, 10.2, and 12.3 microM, respectively.     

Antifungal metabolites from the rhizospheric Penicillium sp. YIM PH 30003 associated with Panax notoginseng

Two new N-benzoylamino acids, peniginseng A-B (1–2), and two new fatty acids, peniciginseng A-B (5–6), were isolated during the fermentation of Penicillium sp. YIM PH30003, an endophytic fungus associated with Panax notoginseng (Burk.) F.H. Chen. Their structures were assigned based on a combination of 1D and 2D NMR and mass spectral data. The N-benzoylamino acids (1–4) might share similar biosynthetic pathways with the rare siderophore pistillarin. Compounds 1–10 showed antifungal activities (MICs 16–128 μg/mL) against Fusarium solani, the pathogenic fungus of P. notoginseng.     

来自普哥滨珊瑚的一株Talaromyces sp.真菌的活性次生代谢产物

利用硅胶柱层析、制备型HPLC和重结晶等手段从普哥滨珊瑚分离的一株Talaromyces sp.真菌C21-1中筛选得到2个活性化合物,运用核磁共振、质谱和圆二色谱等技术鉴定这两个化合物分别为(R)-(-)-hydroxysydonic acid（1）和homodimeric WIN 64821（2）,补充完善了化合物2的核磁共振信号归属,并对化合物进行抗菌活性和乙酰胆碱酯酶抑制活性的测定,发现化合物1对白色假丝酵母Canidia albicans和耐甲氧基青霉素的金黄色葡萄球菌Methicillin-resistant Staphylococcus aureus（MRSA）具有一定的抑制作用,其最低抑菌浓度（MIC）分别为0.075mmol/L和0.2mmol/L,对副溶血弧菌Vibrio parahemolyticus的抑制活性较弱,在0.2mmol/L浓度下的抑制率为17%;化合物2最大浓度0.2mmol/L条件下对这3种菌均没有明显的抑制效果。化合物2表现出剂量依赖的乙酰胆碱酯酶抑制活性,0.5mmol/L时抑制率达到35.1%。     

Sesquiterpenoids from the endophytic fungus Trichoderma sp. PR-35 of Paeonia delavayi

A new bisabolane-type sesquiterpene, trichoderic acid (1), and a new acorane-type sesquiterpene, 2β-hydroxytrichoacorenol (2), along with three known compounds, cyclonerodiol (3), cyclonerodiol oxide (4), and sorbicillin (5), were isolated from the culture broth of Trichoderma sp. PR-35, an endophytic fungus isolated from Paeonia delavayi. Their structures were elucidated on the basis of their IR, MS, and 1D- and 2D-NMR analyses. The antibacterial and antifungal activities of 1-5 towards various types of bacteria and fungi were tested. Most of the compounds showed moderate or weak antimicrobial activities in an agar-diffusion assay.     

Massarilactones E-G, new metabolites from the endophytic fungus Coniothyrium sp., associated with the plant Artimisia maritima

Three new massarilactones E-G (1-3) and the massarilactone acetonide (4) were isolated from the ethyl acetate extract of the endophytic fungus Coniothyrium sp., associated with the plant Artimisia maritima. Their structures were determined by analysis of the 1D and 2D NMR and mass spectroscopic data. The structure of massarilactones E (1) was confirmed by X-ray diffraction analysis, and its absolute configuration determined by the solid-state CD/TDDFT method.     

Enantioseparation of racemic 4-aryl-3,4-dihydro-2(1H)-pyrimidones on chiral stationary phases based on 3,5-dimethylanilides of N-(4-alkylamino-3,5-dinitro)benzoyl L-alpha-amino acids

Three novel chiral packing materials for high-performance liquid chromatography were prepared by covalently binding of (2S)-N-(3,5-dimethylphenyl)-2-[(4-chloro-3,5-dinitrophenyl)carbonylamino]propan-amide (7), (2S)-N-(3,5-dimethylphenyl)-2-[(4-chloro-3,5-dinitrophenyl)carbonylamino]-4-methylpentanamide (8), and (2S)-N-(3,5-dimethylphenyl)-2-[(4-chloro-3,5-dinitrophenyl)carbonyl-amino]-2-phenylacetamide (9) to aminopropyl silica. The resulting chiral stationary phases (CSPs 1-3) proved effective for the resolution of racemic 4-aryl-3,4-dihydro-2(1H)-pyrimidone derivatives (TR 1-14). The mechanism of their enantioselection, supported by the elution order of (S)-TR 13 and (R)-TR 13 and molecular modeling of the complex of the slower running (S)-TR 13 with CSP 1 is discussed.     

Antifungal and new metabolites of Myrothecium sp. Z16, a fungus associated with white croaker Argyrosomus argentatus

AIMS: Fungal infection is still a life-threatening risk for the immunocompromised population such as AIDS patients and those who receive treatments with immunosuppressors and/or frequent administrations of wide-spectrum antibiotics, which inevitably lead to the drug resistance and unbalanced microflora populations. The present work was accordingly performed to characterize more potent antifungal metabolites from various cultures of marine fungi residing in white croaker Argyrosomus argentatus. METHODS AND RESULTS: The three most common opportunistic human pathogens Candida albicans (CCCCM ID 00148), Aspergillus niger (CCCCM ACCC 30005) and Trichophyton rubrum (CCCCM ID 00001) were selected as test fungi. A total of 16 cultivable fungal strains were isolated from the variant tissues of Ar. argentatus collected from the Yellow Sea, followed by preliminary antifungal screenings of the EtOAc extracts of the corresponding cultures. As a result, the inhibition of the three target fungi, plus being allergic to isolators' skin, were discerned with the EtOAc extract of the fungus under the isolation number Z16 that was identified subsequently as Myrothecium sp. by a combination of morphological and 18S rDNA finger-typing characteristics. A follow-up bioassay fractionation of the EtOAc extract, in conjunction with spectral analyses [MS, (1)H-NMR, (13)C-NMR, distortionless enhancement by polarization transfer (DEPT), heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond resonance (HMBC)] wherever required, afforded eventually the characterization of a new acid (compound 1: 4,5-ditridecyl-octanedioic acid), three macrocyclic trichothecenes including roridin A (compound 2), verrucarin A (compound 3) and 8beta-acetoxy-roridin H (compound 4), (22E,24R)-cerevisterol (compound 5) and N-phenyl-beta-amino-naphthalene (compound 6). In vitro antifungal tests showed that the three trichothecenes were active against A. niger, T. rubrum and C. albicans with MICs of 31.25, 62.5 and 125 microg ml(-1) for compound 2, 250, 125 and 31.25 microg ml(-1) for compound 3 as well as 125, 62.5 and 125 microg ml(-1) for compound 4 respectively. The MICs of ketoconazole (co-assayed herewith as a positive reference) against A. niger, T. rubrum and C. albicans were 31.25, 250, 31.25 microg ml(-1) respectively. A preliminary structure-activity relationship of the antifungal trichothecenes was highlighted in brief. CONCLUSIONS: The present investigation demonstrated that marine fungus Myrothecium sp. Z16 associated with white croaker (Ar. argentatus), was an efficient producer of a new acid and antifungal trichothecenes, the latter presumably being also the allergic substances in the culture. SIGNIFICANCE AND IMPACT OF THE STUDY: The title marine fungus was investigated to be a resource of new aliphatic acid, and trichothecenes with potent antifungal and dermal toxic actions.     

一种被毛孢(Hirsutella sp.)培养液中自由基清除剂的分析、分离和制备

[目的]在一次对虫生真菌代谢物进行大规模的清除自由基活性物质筛选中,发现一种被毛孢(Hirsutella sp.)菌株RCEF0881发酵液中存在有较强的清除自由基活性物质.本研究目的是初步搞清这些活性成分的具体组成,并制备出一定量的纯品用于进一步的结构鉴定.[方法]用有机溶剂法提取活性成分;用二苯基苦基苯肼自由基(DPPH)酶标仪法和薄层色谱法进行活性测定;用高分辨液质联用方法进行活性成分初步分析和鉴定;用反相制备色谱法制备活性组分.[结果]提取实验结果表明具清除自由基活性的物质能较好地被乙酸乙酯提取出来;液相色谱-质谱-活性测定分析表明提取物中活性组分的可能分子式分别为C7H6O4、C8H8O3和C12H14N2O.结合色谱特性、紫外光谱特征、质谱碎片和数据库查询可初步推断它们分别为二羟基苯甲酸、羟基甲基苯甲酸和生物碱类物质,但具体结构还有待于进一步确认.从高效液相色谱和质谱离子流的峰面积可知上述3种活性物质中C12H14N2O的含量最高.本研究成功地用反相制备色谱制备出该天然活性组分的纯品.该3种清除自由基活性物质都是首次发现存在于虫生真菌的代谢物中.     

Photoactivation of the manganese catalyst of O2 evolution. I. Biochemical and kinetic aspects

Photosynthetic O₂ evolution requires a Mn complex which is activated by light. An analysis of this activation process yielded the following results:

1.

1. In any given illumination, the time course is first order, the rate being proportional to the number of inactive O₂-evolving System II trapping centers (the quantum yield being invariant).     

Exploring the unbinding of Leishmania (L.) amazonensis CPB derived‐epitopes from H2 MHC class I proteins

New strategies to control Leishmania disease demand an extensive knowledge about several aspects of infection including the understanding of its molecular events. In murine models, cysteine proteinase B from Leishmania amazonensis promotes regulation of immune response, and fragments from its C‐terminus extension (cyspep) can play a decisive role in the host‐parasite interaction. The interaction between cyspep‐derived peptides and major histocompatibility complex (MHC) proteins is a crucial factor in Leishmania infections. Seven cyspep‐derived peptides, previously identified as capable of interacting with H‐2 (murine) MHC class I proteins, were studied in this work. We established a protocol to simulate the unbinding of these peptides from the cleft of H‐2 receptors. From the simulations, we estimated the corresponding free energy of dissociation (ΔG_d) and described the molecular events that occur during the exit of peptides from the cleft. To test the reliability of this method, we first applied it to a calibration set of four crystallographic MHC/peptide complexes. Next, we explored the unbinding of the seven complexes mentioned above. Results were consistent with ΔG_d values obtained from surface plasmon resonance (SPR) experiments. We also identified some of the primary interactions between peptides and H‐2 receptors, and we detected three regions of influence for the interaction. This pattern was systematically observed for the peptides and helped determine a minimum distance for the real interaction between peptides and H‐2 proteins occurring at ～25 Å. Proteins 2016; 84:473–487. © 2016 Wiley Periodicals, Inc.     

Tetralones and flavonoids from Pyrola calliantha

Two new tetralones, pyrolones A (1) and B (2), and a new flavonol glycoside, 2'-O-(4-hydroxybenzoyl)hyperin (3), were isolated from Pyrola calliantha (whole plant), together with six structurally related compounds, including 2'-O-galloylhyperin (4), hyperin (5), formononetin (6), quercetin 3-O-alpha-L-arabinopyranoside (7), quercetin 3-O-alpha-L-arabinofuranoside (8), and kaempferol 3-O-beta-D-galactopyranoside (9). The structures and absolute configurations of the new compounds were elucidated on the basis of spectroscopic (UV, ORD, CD, NMR) and mass-spectrometric (HR-ESI-MS) analyses.     

Biogenesis of chloroplast membranes X. Changes in the photosynthetic specific activity and the relationship between the light harvesting system and photosynthetic electron transfer chain during greening of Chlamydomonas reinhardi y-1 cells

Specific activities of photophosphorylation and light-dependent pH rise at different stages of the greening process, have been measured as a function of the illumination intensity.     

Metabolites from Two Dominant Thermophilic Fungal Species Thermomyces lanuginosus and Scytalidium thermophilum

Thermomyces lanuginosus and Scytalidium thermophilum are among the most ubiquitous thermophilic fungi in compost and soil. Chemical study on these two prevalent strains collected from Yunnan led to isolation of 23 metabolites, including one new metabolite, therlanubutanolide, and 15 known compounds, isolated from the YGP culture broth of Thermomyces lanuginosus and 7 known compounds isolated from Scytalidium thermophilum, respectively. Therlanubutanolide shared the quite similar features of the same carbon skeleton and saturation as natural hexadecanoic acids. This was the first reported discovery of such a lactone as natural occurring metabolite. All the compounds were reported for the first time from thermophilic fungi. Among them, N‐[(2S,3R,4E,8E)‐1,3‐dihydroxy‐9‐methyloctadeca‐4,8‐dien‐2‐yl]acetamide was for the first time reported to be a naturally occurring metabolite and its NMR data was first provided in this study. A type of PKS‐derived metabolites, three 3,4‐dihydronaphthalen‐1(2H)‐ones, which were widely found in plant pathogenic fungi as phytotoxins and reported to have antimicrobial activity, were obtained from both dominant thermophilic fungi. The frequent occurrence of such PKS phytotoxins in these two thermophilic fungi might suggest particular ecological interest.     

1H NMR studies of drugs with achiral and chiral lanthanide shift reagents: Applications to the anticonvulsant pheneturide

The anticonvulsant pheneturide, PNT, has been studied by 300 MHz ¹H NMR in CDCl₃ at ambient temperatures with the achiral lanthanide shift reagent (LSR) Eu(FOD)₃, and with the chiral LSR, Eu(HFC)₃. Both LSRs produced spectral simplification of the aryl proton signal region, and substantial lanthanide‐induced shifts (LIS). With added Eu(HFC)₃, enantiomeric shift differences (ΔΔδ) were induced for most nuclei of PNT, indicating substantial potential for direct determination of enantiomeric excess. Valley heights between corresponding signals in the PNT enantiomers as low as 3.6% were achieved for the meta resonance. Least squares line‐fitting was applied to the variation of chemical shift vs. [LSR]/[PNT] molar ratios for both LSRs. Tentative assignments were made for the NH absorptions based on two‐dimensional NMR (COSY45), as well as their relative magnitudes of LIS, ΔΔδ, and lanthanide‐induced line broadening. The PNT conformation reported in the crystal is believed to be retained in solution with added LSR. The relative senses of magnetic nonequivalence were found to be the same among the three sets of aryl protons, and among the three kinds of protons in the ethyl moiety, with high levels of added chiral LSR, using 2D NMR. Chirality 11:529–535, 1999. © 1999 Wiley‐Liss, Inc.     

Isolation and properties of particles containing the reactioncenter complex of Photosystem II from spinach chloroplasts

By density gradient centrifugation of the 80000 × g supernatant of digitonintreated spinach chloroplasts two main green bands and one minor green band were obtained. The purification and properties of the particles present in the main bands, which were shown to be derived from Photosystem I and Photosystem II, have been described previously; those of the particles in the minor fraction will be described in the present paper.

After purification, these particles show Photosystem II activity but are devoid of Photosystem I activity. They have a high chlorophyll a/chlorophyll b ratio and are enriched in β-carotene and cytochrome b₅₅₉. At liquid nitrogen temperature, photoreduction of C550 and photooxidation of cytochrome-b₅₅₉ can be observed. At room temperature, cytochrome b₅₅₉ undergoes slight photooxidation.

These properties indicate that this particle may be the reaction-center complex of Photosystem II. It is suggested that, in vivo, the Photosystem II unit is made up of a reaction-center complex and an accessory complex, the latter being found in one of the main green bands of the density gradient.     

Studies on electron transport associated with Photosystem I. I. Functional site of plastocyanin: Inhibitory effects of HgCl2 on electron transport and plastocyanin in chloroplasts

1. Incubation of chloroplasts with HgCl₂ at a molar ratio of HgCl₂ to chlorophyll of about unity, induced a complete inhibition of the methyl viologen Hill reaction, as well as methyl viologen photoreduction with reduced 2,6-dichlorophenolindophenol (DCIP) as electron donor. Photooxidation of cytochrome ? was similarly sensitive towards HgCl₂, whereas photooxidation of P700 was resistant to the poison. Photoreduction of cytochrome ? and light-induced increase in fluorescence yield were enhanced by the HgCl₂ treatment of chloroplasts.