Phenethyl angelate - a new ester from immortelle essential oil?

Esters of angelic, senecioic and tiglic acids with various saturated/ unsaturated/aromatic alcohols contribute to the aroma of many essential oils. However, mass spectrometry with electron-impact ionization sometimes fails to distinguish these regio-/geometric isomers and this was the case with the minor constituent of Helichrysum italicum (immortelle) essential oil that was tentatively identified as the ester of 2- phenyl-1-ethanol with one of the mentioned acids. Our efforts to identify this phenethyl ester were also hampered by the inconsistency or by the lack of appropriate RI data in the literature. Therefore, we prepared and fully spectrally characterized (1D- and 2DNMR, IR, MS) synthetic samples of all three isomeric esters. Subsequent GC analyses of immortelle oil samples with spiked synthetic phenethyl esters unambiguously confirmed that the compound in question was phenethyl angelate. This rare plant secondary metabolite has been previously reported only twice as a constituent of samples of natural origin. However, the outcomes of our study strongly imply that this molecule was misidentified in these earlier studies with the corresponding senecioate/tiglate. Thus, the existing libraries of RI/MS data for tiglates and angelates have to be upgraded with appropriate data for senecioates to avoid these kinds of errors in the future.

Pyrrovobasine, Hybrid Alkylated Pyrraline Monoterpene Indole Alkaloid Pseudodimer Discovered Using a Combination of Mass Spectral and NMR-Based Machine Learning Annotations

A new vobasine-tryptamine-based monoterpene indole alkaloid pseudodimer was isolated from the stem bark of Voacanga africana. As a minor constituent occurring in a thoroughly investigated plant, this molecule was targeted...

Friction Weldability of a High Nb Containing TiAl Alloy

The friction weldability of Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y alloy has been investigated by optimizing process parameters and analyzing the microstructures and tensile properties of the joints. The as-cast alloy with a nearly lamellar (NL) microstructure and the as-forged alloys with a duplex (DP) microstructure have been successfully welded. All the joints have a severe deformation zone (SDZ) and a transition zone (TZ) between the parent metal (PM) and SDZ. SDZ, showing a biconcave lens geometry, has a maximum thickness of hundreds of micrometers at the periphery. TZ is hundreds of micrometers thick. All SDZs have a fine-grained DP microstructure with a grain size of a few micrometers. For the joint of the as-cast alloy, the TZ consists of deformed lamellar colonies as the major constituent and partially recrystallized grains as the minor constituent. For the joint of the as-forged alloy, the TZ is similar to both the PM and SDZ, showing a DP microstructure. The grain size, volume fraction of γ grains, and the remnant lamellar colonies all increase with the distance from the SDZ. All joints presented perfect metallurgical bonding. The strengths of the joints are higher than those of the corresponding PMs. This indicates that the studied alloy has good friction weldability.

Characterization of xyloglucan-specific fucosyltransferase activity in Golgi-enriched microsomal preparations from wheat seedlings

Xyloglucan (XyG) is a major hemicellulosic polymer in primary cell walls of dicotyledonous plants but represents only a minor constituent of cell walls from graminaceous monocotyledons (Poaceae). Our current information on XyG biosynthesis in vitro comes exclusively from studies on dicotyledonous plants. While XyG has been reported in grass cell walls, there are no studies of XyG biosynthesis in vitro in grasses. In this report, we investigated XyG structure and biosynthesis in etiolated wheat seedlings and showed that their walls contain small amounts (4-14%) of XyG. Furthermore, structural analysis using electrospray ionization mass spectrometry (ESI-MS) and high pH anion exchange chromatography (HPAEC) revealed that wheat XyG may be of XXGGG-type. Interestingly, detergent extracts from root microsomes were able to fucosylate tamarind XyG in vitro in a similar way as fucosyltransferase activity from Arabidopsis thaliana (AtFUT1) and pea (PsFUT1). Endoglucanase digestion of the [14C]fucosylated-tamarind XyG formed by the wheat fucosyltransferase activity released radiolabeled oligosaccharides that co-eluted with authentic fucoslyated XyG oligosaccharides (XXFG and XLFG). Although wheat fucosyltransferase activity was low, it appeared to be specific to XyG and required divalent ions (Mg2+ or Mn2+) for full activity. Together, these results suggest that the XyG fucosylation mechanism is conserved between monocots and dicots.

Solvoltylic micellization dalam penjumputan karoten dari biodiesel sawit

Carotene is a minor constituent with concentration of hundreds of ppm in Crude Palm Oil, which has economic value much more than biodiesel. Carotene in palm biodiesel (alkyl ester) needs to be concentrated before doing main process for its recovery. Solvolytic micellization is a good method to concentrate carotene in palm biodiesel. The objectives of this research are to know the best type and composition of solvents used and to evaluate effectiveness of multistage solvolytic micellization. Before running solvolytic micellization, adsorption process using Al2O3, Ca(OH)2 and activated carbon adsorbents is done to proof the importance of thickening process in carotene recovery from palm biodiesel. In this research, minor solvent is water. Types of tried major solvents are acetone, isopropanol, ethanol and methanol. To determine the best solvents composition, volumetric ratio of major solvent to crude biodiesel is varied from 1 to 8 and minor solvent to major solvent from 1% to 5%. Number of stages done in evaluation of multistage solvolytic micellization is 5. Parameters evaluated in every stage's output are shrinkage occurred and carotene content & yield. According to this research, the best main solvent is methanol. The best volumetric ratios of methanol to crude biodiesel and water to methanol are 5 and 2.5% respectively. Performing 5 stages of solvolytic micellization with the best condition according to this research can concentrate carotene from 649 ppm (0.0649%) to 70228ppm (7.0228%).Keywords: Palm Biodiesel; Carotene; Recovery; Solvolytic Micellization AbstrakKaroten adalah salah satu senyawa minor berkadar ratusan ppm dalam minyak sawit mentah yang memiliki nilai ekonomis jauh lebih tinggi dari biodiesel. Karoten dalam biodiesel (ester alkif) sawit perlu dipekatkan sebelum pelaksanaan proses utama penjumputannya. Solvolytic micellization merupakan metoda yang baik untuk memekatkan karaten di dalam biodiesel sawit. Tujuan penelitian ini adalah untuk mengetahui jenis dan komposisi terbaik pelarut serta mengevaluasi keefektifan multistage solvolytic micellization. Sebelum tempuhan solvolytic micellization dilakukan pembuktian perlunya proses pemekatan dalam penjumputan karaten dari biodiesel sawit melalui proses adsorpsi menggunakan adsorben Al2O3, Ca(OH)2 dan karbon aktif. Dalam penelitian ini, pelarut minor yang digunakan adalah air. Jenis-jenis pelarut utama yang dicoba adalah aseton, isopropanol, etanol, dan metana. Untuk menentukan komposisi terbaik pelarut, variasi dilakukan pada perbandingan volum pelarut utama terhadap volum biodiesel mentah (1 s/d 8) dan perbandingan volum pelarut minor terhadap volum pelarut utama (1 s/d 5 %). Untuk mengevaluasi keefektifan multistage solvolytic micellization, jumlah tahap yang dilakukan adalah 5. Parameter-parameter yang dievaluasi pada hasil dari setiap tahap yang dilakukan adalah penyusutan yang terjadi beserta kadar dan perolehan karoten yang dihasilkan. Pelarut utama terbaik menurut penelitian ini adalah metanol. Perbandingan volum metanol terhadap volum biodiesel mentah dan perbandingan volum air terhadap volum metanol yang terbaik secara berturut turut adalah 5 dan 2.5 %. Dengan melakukan solvolytic micellization sebanyak 5 tahap pada kondisi terbaik menurut hasil penelitian ini bisa memekatkan karoten dari konsentrasi 649ppm (0,0649%) menjadi 70228ppm (7,0228%).Kata Kunci: Biodiesel Sawit; Karoten; Penjumputan; Solvolytic Micellization

Cupolamide B, A Cyclic Heptapeptide from Theonella cupola

A new cyclic heptapeptide named cupolamide B (2) was isolated as a minor constituent from the Okinawan sponge Theonella cupola. The structure was elucidated by analyzing spectral data in combination with Marfey analysis of its acid lysate.

Essential Oil Composition and Antibacterial Activity of Hyptis colombiana from the Venezuelan Andes

Hyptis colombiana is an aromatic shrub native to the Colombian and Venezuelan Andes. Aerial parts were collected in Mérida State at about 3100 m above sea level in February 2005, and May and October 2006. The essential oil was found to contain germacrene D and β-caryophyllene as main constituents (about 50%). The February 2005 and October 2006 oils were found to have antibacterial activity against Staphylococcus aureus, but not the May 2006 oil, probably due to the lack of some minor constituent.