Colour and stability of pure anthocyanins influenced by pH including the alkaline region

This study on anthocyanin colour variation (intensity, lambda max, absorptivity) over the pH range 1-9 during 60 days of storage, was conducted on petunidin 3-[6-O-(4-O-E-p- coumaroyl-O-alfa-L-rhamnopyranosyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside (petanin) and cyanidin 3-O-beta-D-glucopyranoside (cy3glc) at 10 and 23ºC. Compared to cy3glc, petanin afforded higher colour intensity and higher or similar stability throughout the whole pH range. At pH 4.0, 84% of petanin was intact after 60 days storage at 10ºC, while the corresponding solution of cy3glc was totally degraded. At pH 8.1 the colour intensity of petanin was even higher than at the lowest pH values. The visible lambda max absorption of petanin after 5 days at pH 8.1 at 10ºC was similar or higher than the corresponding absorptions of the fresh solutions of cy3glc at any pH. The use of anthocyanins like petanin as food colorants in slightly alkaline products (bakery, milk, egg, etc.) should therefore be considered at least in products with limited storage time kept in a refrigerator.Fundação para a Ciência e Tecnologi

Novel GHB-derived natural products from European mistletoe (Viscum album)

Context: The European white-berry mistletoe [Viscum album L. (Loranthaceae)] is among the oldest known medicinal plants. At present the most important application of mistletoe extracts is in the treatment of cancer. However, natural products specific to mistletoe have rarely been encountered in the current literature. Objective: To discover novel natural products specific to European mistletoe. Materials and methods: European mistletoe was extracted with methanol, purified to partition against diethyl ether and further purified with XAD-7 column chromatography. Pure compounds were separated by Sephadex column chromatography and preparative HPLC. The structures of the novel compounds were established using a combination of several 2D NMR spectroscopic techniques and mass spectrometry. Results: A new type of natural product derived from the methyl ester of g-hydroxybutyric acid (GHB) coupled to hydroxybenzoic acids, namely 3-(3'-carbomethoxypropyl) gallic acid and 3-(3'-carbomethoxypropyl)-7→3''-protocatechoyl galloate were characterized from European white-berry mistletoe. Condensation of the 3-hydroxyl of gallic acid with the 4-hydroxyl of GHB significantly reduced the radical scavenging properties of the former compound. Discussion and conclusion: The characterized compounds define a novel group of natural products that may be of particular interest because it appears that the two new compounds are not closely related to any known natural product.acceptedVersio

Acylated Flavone O-Glucuronides from the Aerial Parts of Nepeta curviflora

Nepeta curviflora Boiss. (Syrian catnip) is native to the Middle East. This medicinal plant is commonly used against nervous disorders, rheumatic pains, and high blood pressure. Herbal infusions prepared from various Nepeta spp. are extensively consumed as functional food. However, limited information has been known about the phenolic constituents of Syrian catnip. In this study, two acylated flavone 7-O-glucuronides, apigenin 7-O-(2″-O-(2‴-(E-caffeoyl)-β-glucuronopyranosyl)-β-glucuronopyranoside) (1) and luteolin 7-O-(2″-O-(2‴-(E-caffeoyl)-β-glucuronopyranosyl)-β-glucuronopyranoside) (2), along with the known phenolic compounds rosmarinic acid, caffeic acid, apigenin, and apigenin 7-O-β-glucopyranoside were isolated from the aerial parts of N. curviflora. The characterizations of these compounds were based on high-resolution mass spectrometry, UV, and extensive use of multidimensional NMR spectroscopy. The new compounds (1 and 2) were identified in the unmodified state and as dimethylesters.publishedVersio

Natural Products from Leaves of the Ancient Iranian Medicinal Plant Echium amoenum Fisch. & C. A. Mey.

For several millennia, leaves of Echium amoenum Fisch. & C. A. Mey., an important Iranian medicinal plant with nutritional value as nutraceutical, have been used as tea for the treatment of several conditions, including inflammation. The nutritional value of intake of E. amoenum tea has mainly been correlated to its rich content of mainly water-soluble antioxidants. Although the entire plant is utilized, only natural products of the flowers have previously been thoroughly investigated. The rare natural products bis(3-(3,4-dihydroxyphenyl)-1-methoxy-1-oxopropan-2-yl)-1-(3,4-dihydroxyphenyl)-6,7-dihydroxy-1,2-dihydronaphthalene-2,3-dicarboxylate, 4-Oxy-(E)-caffeoyl-2,3-dihydroxybutanoic acid methyl ester and 4-Oxy-(Z)-caffeoyl-2,3-dihydroxybutanoic acid methyl ester, in addition to the widely distributed compounds rosmarinic acid methyl ester and (E)-caffeic acid, were purified and characterized from leaves of Echium amoenum. The structures were determined by a combination of several 2D NMR spectroscopic techniques, circular dichroism spectroscopy and high-resolution mass spectrometry. The fact that bis(3-(3,4-dihydroxyphenyl)-1-methoxy-1-oxopropan-2-yl)-1-(3,4-dihydroxyphenyl)-6,7-dihydroxy-1,2-dihydronaphthalene-2,3-dicarboxylate belongs to a rare group of natural products which have previously been patented for their significant anti-inflammatory activity may rationalize the traditional treatment of inflammations with E. amoenum.publishedVersio

A novel bicyclic lactone and other polyphenols from the commercially important vegetable Anthriscus cerefolium

Garden chervil, Anthriscus cerefolium (L.) Hoffm. is an important herb commonly applied in Norwegian large-scale commercial kitchens. This species is a highly enriched source of phenolics, containing 1260 mg gallic acid equivalents (GAE) 100–1 g DM, however, the individual phenolic compounds have been scarcely characterized. Here we report on the qualitative and quantitative content of phenolics in garden chervil. The structure of the main phenolic compound was elucidated to be the previously undescribed compound 1,3-dicaffeoyl-5-malonyl-δ-quinide (1) by means of 1D- and 2D NMR and high-resolution mass spectrometry. The known flavones apigenin 7-O-β-(2″-apiofuranosylglucopyranoside) (= apiin) (2), apigenin 7-(2″-apiosyl-6″-malonylglucoside) (3) and luteolin 7-glucoside (4) were also identified. Compound 3 is reported for the first time from this plant species. The main phenolic compound, 1,3-dicaffeoyl-5-malonyl-δ-quinide, exhibited moderate cytotoxicity towards acute monocytic leukaemia cells (MOLM-13) and rat kidney epithelial cells (NRK) with EC50 between 400 and 600 µM.publishedVersio

Agrárpiaci Információk

Az AKI Agrárpiaci Információk című, havi megjelenési gyakoriságú kiadványának elsődleges célja a kisebb üzemméretű mezőgazdasági termelők ellátása a gazdálkodásukhoz szükséges aktuális információkkal. Ezen információk körébe tartozik a fontosabb mezőgazdasági termékek és a mezőgazdasági inputok piaci helyzetének alakulása. Emellett árinformációk, külkereskedelmi és egyéb agrárstatisztikai adatok és ahhoz kapcsoló elemzések is közlésre kerülnek a kiadványban

Glutamic Acid Residues in HIV-1 p6 Regulate Virus Budding and Membrane Association of Gag

The HIV-1 Gag p6 protein regulates the final abscission step of nascent virions from the cell membrane by the action of its two late (l-) domains, which recruit Tsg101 and ALIX, components of the ESCRT system. Even though p6 consists of only 52 amino acids, it is encoded by one of the most polymorphic regions of the HIV-1 gag gene and undergoes various posttranslational modifications including sumoylation, ubiquitination, and phosphorylation. In addition, it mediates the incorporation of the HIV-1 accessory protein Vpr into budding virions. Despite its small size, p6 exhibits an unusually high charge density. In this study, we show that mutation of the conserved glutamic acids within p6 increases the membrane association of Pr55 Gag followed by enhanced polyubiquitination and MHC-I antigen presentation of Gag-derived epitopes, possibly due to prolonged exposure to membrane bound E3 ligases. The replication capacity of the total glutamic acid mutant E0A was almost completely impaired, which was accompanied by defective virus release that could not be rescued by ALIX overexpression. Altogether, our data indicate that the glutamic acids within p6 contribute to the late steps of viral replication and may contribute to the interaction of Gag with the plasma membrane

The Host-Pathogen interaction of human cyclophilin A and HIV-1 Vpr requires specific N-terminal and novel C-terminal domains

<p>Abstract</p> <p>Background</p> <p>Cyclophilin A (CypA) represents a potential key molecule in future antiretroviral therapy since inhibition of CypA suppresses human immunodeficiency virus type 1 (HIV-1) replication. CypA interacts with the virus proteins Capsid (CA) and Vpr, however, the mechanism through which CypA influences HIV-1 infectivity still remains unclear.</p> <p>Results</p> <p>Here the interaction of full-length HIV-1 Vpr with the host cellular factor CypA has been characterized and quantified by surface plasmon resonance spectroscopy. A C-terminal region of Vpr, comprising the 16 residues ⁷⁵GCRHSRIGVTRQRRAR⁹⁰, with high binding affinity for CypA has been identified. This region of Vpr does not contain any proline residues but binds much more strongly to CypA than the previously characterized N-terminal binding domain of Vpr, and is thus the first protein binding domain to CypA described involving no proline residues. The fact that the mutant peptide Vpr^75-90R80A binds more weakly to CypA than the wild-type peptide confirms that Arg-80 is a key residue in the C-terminal binding domain. The N- and C-terminal binding regions of full-length Vpr bind cooperatively to CypA and have allowed a model of the complex to be created. The dissociation constant of full-length Vpr to CypA was determined to be approximately 320 nM, indicating that the binding may be stronger than that of the well characterized interaction of HIV-1 CA with CypA.</p> <p>Conclusions</p> <p>For the first time the interaction of full-length Vpr and CypA has been characterized and quantified. A non-proline-containing 16-residue region of C-terminal Vpr which binds specifically to CypA with similar high affinity as full-length Vpr has been identified. The fact that this is the first non-proline containing binding motif of any protein found to bind to CypA, changes the view on how CypA is able to interact with other proteins. It is interesting to note that several previously reported key functions of HIV-1 Vpr are associated with the identified N- and C-terminal binding domains of the protein to CypA.</p

PERBANDINGAN HASIL BELAJAR SISWA YANG MENGGUNAKAN E-BOOK DAN BUKU PAKET PADA MATERI EKOSISTEM DI KELAS X MAN BUNTET PESANTREN CIREBON

Berbagai bahan ajar atau sumber belajar yang ditawarkan kepada guru, kurang dimanfaatkan dengan baik, terutama oleh guru Biologi, sehingga pencapaian tujuan yang ditunjukkan siswa tidak sesuai dengan harapan. Bahan ajar eBook dan buku paket adalah alat pembelajaran yang dapat digunakan guru dalam menyampaikan materi Biologi. Bahan ajar eBook ini merupakan sumber belajar baru yang menyenangkan. eBook ini menyajikan mata pelajaran kepada siswa dengan memiliki kepraktisan dalam belajar. Berdasarkan hasil wawancara dengan salah satu guru Biologi dan siswa di MAN Buntet Pesantren Cirebon, proses pembelajaran Biologi di sekolah ini biasa menggunakan bahan ajar LKS dengan menyisipkan sesekali bahan ajar buku paket. Ini belum cukup untuk meningkatkan hasil belajar siswa. Penelitian ini bertujuan untuk mengkaji hasil belajar ekosistem yang menggunakan bahan ajar eBook dan pembelajaran dengan menggunakan bahan ajar buku paket. eBook sendiri merupakan buku yang berbentuk elektronik atau softcopy, sedangkan buku paket / pelajaran adalah tulisan seorang pengarang atau tim pengarang yang disusun dalam penelitian berdasarkan kurikulum atau tafsiran tentang kurikulum yang berlaku. Hasil belajar adalah tingkat penguasaan yang dicapai siswa dalam mengikuti program belajar mengajar sesuai dengan tujuan pendidikan yang ditetapkan melalui aspek kognitif. Ekosistem adalah kesatuan lingkungan hidup yang melakukan interaksi / timbal balik dengan lingkungannya. Penelitian ini dilakukan di MAN Buntet Pesantren Cirebon dengan populasi semua kelas X. Sampel kelas X.5 sebagai kelas eksperimen dan X.6 sebagai kelas kontrol. Penelitian ini dilakukan dari tanggal 23 april sampai 23 juni 2012, dengan menggunakan metode eksperimen dengan desain penelitian Randomized Control Group Pretest-posttest dan teknik pengumumpulan datanya dengan menggunakan test. Dari hasil penelitian diperoleh hasil belajar ekosistem siswa yang menggunakan bahan ajar eBook dan bahan ajar buku paket. Nilai rata-rata hasil belajar ekosistem, kelas eksperimen yang menggunakan baha ajar eBook adalah 54 pada pretest dan pada posttest adalah 74, sedangkan pada kelas kontrol dengan rata-rata 50 pada pretest dan pada posttest adalah 71. Dapat disimpulkan bahwa tidak terdapat perbedaan yang signifikan antara kelas yang menggunakan eBook dan buku paket. Kata Kunci : Hasil Belajar, Penggunaan eBook dan Buku Paket, Ekosiste

The intriguing Cyclophilin A-HIV-1 Vpr interaction: prolyl cis/trans isomerisation catalysis and specific binding

<p>Abstract</p> <p>Background</p> <p>Cyclophilin A (CypA) represents a potential target for antiretroviral therapy since inhibition of CypA suppresses human immunodeficiency virus type 1 (HIV-1) replication, although the mechanism through which CypA modulates HIV-1 infectivity still remains unclear. The interaction of HIV-1 viral protein R (Vpr) with the human peptidyl prolyl isomerase CypA is known to occur <it>in vitro </it>and <it>in vivo</it>. However, the nature of the interaction of CypA with Pro-35 of N-terminal Vpr has remained undefined.</p> <p>Results</p> <p>Characterization of the interactions of human CypA with N-terminal peptides of HIV-1 Vpr has been achieved using a combination of nuclear magnetic resonace (NMR) exchange spectroscopy and surface plasmon resonance spectroscopy (SPR). NMR data at atomic resolution indicate prolyl <it>cis</it>/<it>trans </it>isomerisation of the highly conserved proline residues Pro-5, -10, -14 and -35 of Vpr are catalyzed by human CypA and require only very low concentrations of the isomerase relative to that of the peptide substrates. Of the N-terminal peptides of Vpr only those containing Pro-35 bind to CypA in a biosensor assay. SPR studies of specific N-terminal peptides with decreasing numbers of residues revealed that a seven-residue motif centred at Pro-35 consisting of RHFPRIW, which under membrane-like solution conditions comprises the loop region connecting helix 1 and 2 of Vpr and the two terminal residues of helix 1, is sufficient to maintain strong specific binding.</p> <p>Conclusions</p> <p>Only N-terminal peptides of Vpr containing Pro-35, which appears to be vital for manifold functions of Vpr, bind to CypA in a biosensor assay. This indicates that Pro-35 is essential for a specific CypA-Vpr binding interaction, in contrast to the general prolyl <it>cis</it>/<it>trans </it>isomerisation observed for all proline residues of Vpr, which only involve transient enzyme-substrate interactions. Previously suggested models depicting CypA as a chaperone that plays a role in HIV-1 virulence are now supported by our data. In detail the SPR data of this interaction were compatible with a two-state binding interaction model that involves a conformational change during binding. This is in accord with the structural changes observed by NMR suggesting CypA catalyzes the prolyl <it>cis/trans </it>interconversion during binding to the RHFP³⁵RIW motif of N-terminal Vpr.</p