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N-glycans are biologically important oligosaccharides associated with the asparagine residue that may exist in protein-bound or unbound forms in all eukaryotes (including yeasts) and some bacteria. The- core structure of these oligosaccharides is based on the trimannosyl chitobiose structure resulting from cellular N-glycosylation. Preparative-scale amounts of these oligosaccharides are important for chemical, structural and functional studies due to their biological significance. Therefore, we explored a biochemical approach of oligosaccharide preparation using mutant-derived monoglucosylated lipid-linked oligosaccharides (LLOs) required for the assembly of N-linked glycoproteins and non-monoglucosylated free-oligosaccharides (fOSs) from misfolded N-linked glycoproteins using an N-glycosylation (alg) mutant of Saccharomyces cerevisiae. Oligosaccharide extracts of fOSs and LLOs from the alg8 S. cerevisiae mutant lacking the ALG8 gene were profiled using fluorescence- and evaporative light scattering-based HPLC. LLOs did not produce accumulated levels of the target mutant- related monoglucosylated (Glc1Man9GlcNAc2) at 100 ml scale. However, it was possible to detect truncated oligomannose (paucimannose) structures in the fOSs of the alg8 mutant.

A new indole alkaloid, 7-hydroxyspeciociliatine (1), was isolated from the fruits of Malaysian Mitragyna speciosa Korth., together with 11 known indole and oxindole alkaloids (3–13). The structure of the new compound was determined by spectroscopic analysis and chemical conversion. The opioid agonistic activity of the new alkaloid was investigated in guinea-pig ileum experiments. The compound was found to have a weak stimulatory effect on μ-opioid receptors.

A new modified stilbene dimer, diptoindonesin D (1), was isolated from the acetone extract of the tree bark of Hopea dryobalanoides, together with seven known compounds, parviflorol (2), (D)-balanocarpol (3), heimiol A (4), hopeafuran (5), (+)-α-viniferin (6), vaticanol B (7) and (D)-hopeaphenol (8). Cytotoxic properties of compounds 1-8 were evaluated against murine leukemia P-388 cells. Compound 8 was found to be the most active with IC50 of 5.7 μm

Two new indole alkaloids with the methyl chanofruticosinate skeletal system viz., methyl 3-oxo-12-methoxy-N1-decarbomethoxy-14,15-didehydrochanofruticosinate (1) and methyl 3-oxo-11,12-methylenedioxy-N-decarbomethoxy-14,15-didehydrochanofruticosinate (2), together with four known compounds, methyl 12-methoxy-N1-decarbomethoxychanofruticosinate, methyl 12-methoxychanofruticosinate, methyl 11,12-dimethoxychanofruticosinate and methyl 11,12-methylenedioxy-N1-decarbomethoxychanofruticosinate, were isolated in continuing studies on the leaves of Kopsia flavida Blume. The structures of the new indole alkaloids were assigned by NMR spectral data using various 2D-techniques.

A new Corynanthe-type indole alkaloid, (−)-9-methoxymitralactonine ( 1 ), having a highly conjugated system was isolated from the young leaves of Mitragyna speciosa in Malaysia, and its structure was first deduced by spectroscopic analysis and then confirmed by chiral-total synthesis starting from optically pure epoxy-ketone and 5-methoxy-3,4-dihydro-β-carboline. The chiral HPLC analysis demonstrated that the natural 9-methoxymitralactonine contained predominantly the (−)-enantiomer over the (+)-enantiomer in the ratio of 62:38.

Three new monoterpenoid indole alkaloids, i.e., 3,4,5,6-tetradehydromitragynine, mitralactonal, and mitrasulgynine carrying a sulfonate function, were isolated, together with seven known compounds, from the leaves of Mitragyna speciosa native to Malaysia.

The title compound, C19H18O5, is a diastereoisomer of crotocaudin, both being isolated from the plants of genus Croton. In isocrotocaudin, the furan moiety makes a dihedral angle with the adjacent lactone of 13.53 (17)°. The cyclo­hexyl ring of the diterpene moiety adopts a chair confirmation. The weak intermolecular C—H⋯O hydrogen bonds link the mol­ecules into linear chains along the c axis.

A known steroidal compound namely pregnenolone has been isolated from the roots of Holarrhena curtisii. The structure was elucidated through a combination of NMR, IR, GC-MS and MS method.

Equimolecular amounts of amino acids (l-leucine and l-valine) and d-glucose were refluxed at 140 °C for 2 h in propylene glycol. The volatiles were isolated by simultaneous steam distillation and extraction. The extracts were separated in advance by column chromatography on silica gel with a benzene−ether gradient. The resulting fractions were analyzed by GC and GC-MS. Twenty-seven compounds, including 13 pyrazines, 6 dioxolanes, 2 aldehydes, 2 acids, and 2 pyridines, were identified. Dioxolanes, aldehydes, and pyrazines are the major volatiles, and the percentages of their total gas chromatographic peak areas are 41.13, 23.67, and 17.69 respectively. Formation pathways and sensory properties are described. Keywords: Volatile compounds; Maillard reaction; model reaction system

The title compound, C13H10O2, has a trans configuration about the C=C double bond of the phenylethyl­ene side chain and the mol­ecule is nearly planar, with a dihedral angle between the pyrone and benzene rings of 8.54 (6)°. The crystal packing is stabilized by intermolecular C—H⋯O interactions, which form one-dimensional zigzag chains parallel to [100].

Mitragynine is one of the most dominant indole alkaloids present in the leaves of Mitragyna speciosa , a species of Rubiaceae. This alkaloid is believed to be synthesized via condensation of the amino acid derivative, tryptamine and secologanine by the action of strictosidine synthase (STR). The cDNA clone encoding STR from M. specios a was cloned through reverse-transcription polymerase chain reaction (RT-PCR) and denoted as StrMs1. The clone is a full-length cDNA with a size of 1257 bp, which contains an open reading frame of 1056 bp starting from base pair 18 to 1076. Sequence analysis showed that StrMs1 has high homology with other STRs of TIA-producing plants. Nucleotide sequence of StrMs1 was deposited in GenBank with accession number ADK91432. The deduced amino acid sequence has 352 residues with a predicted molecular weight of 39 kDa and isoelectric point at pH 5.78. Southern blot performed showed that there is only one copy of StrMs1 present in the genome of M. speciosa . Expression pattern on different tissues tested using RT-PCR revealed that besides leaf, the expression was also detected in root, stem and flower. Expression profiles under plant defense signal using salicylic acid (SA) was investigated on leaf tissues and the results showed that the transcript of StrMs1 were detected before and after treatment with salicylic acid. Result obtained from phylogenetic analysis suggested that StrMs1 is the most evolved protein among other STRs. However, the 3-D prediction of StrMs1 showed that there are alpha helices and beta propeller structures, which remain conserved withother STRs. Key word: Strictosidine synthase, Mitragyna speciosa, StrMs1, semiquantitative reverse-transcription polymerase chain reaction (RT-PCR), molecular evolution, protein prediction.

The structure of mitragynaline, an indole alkaloid isolated from Malaysian Mitragyna speciosa, was revised as formula 3 by analysis of the NMR spectra measured at low temperature and by chemical transformation with DDQ oxidation from the known alkaloid mitragynine ( 5 ).

Three new monoterpenoid indole alkaloids, i.e., 3,4,5,6-tetradehydromitragynine, mitralactonal, and mitrasulgynine carrying a sulfonate function, were isolated, together with seven known compounds, from the leaves of Mitragyna speciosa native to Malaysia.

The structure of mitragynaline, an indole alkaloid isolated from Malaysian Mitragyna speciosa, was revised as formula 3 by analysis of the NMR spectra measured at low temperature and by chemical transformation with DDQ oxidation from the known alkaloid mitragynine ( 5 ).

Nine alkaloids from Alstonia angustifolia have been assessed for antiprotozoal activities against Entamoeba histolytica and Plasmodium falciparum in vitro. Three dimeric alkaloids, macroacarpamine, macralstonine acetate (semisynthetic) and villastonine were found to possess significant activity against both protozoans, but were 4-8 times less potent than emetine against E. histolytica and 15-50 times less potent than chloroquine against P. falciparum. The monomeric alkaloids, alstonerine, alstophylline, 11-methoxyakuammicine, norfluorocurarine, pleiocarpamine and vincamajine were all considerably less active than the dimers : macralstonine base was found to be inactive

A new 2-arylbenzofuran derivative (diptoindonesin G) (1), along with nine known oligostilbenes, have been isolated and identified from the acetone extract of the tree bark of Hopea mengarawan. The structures of these compounds were determined based on spectroscopic data, including 2D NMR and HREIMS spectra. On cytotoxic evaluation of the isolated compounds against murin leukemia P-388 cells, compound 1 was the strongest in inhibiting the growth of the cells.

article i nfo Inflammatory reactions in the CNS, resulting from a loss of control and involving a network of non-neuronal and neuronal cells, are major contributors to the onset and progress of several major neurodegenerative diseases. Therapeutic strategies should therefore keep or restore the well-controlled and finely-tuned balance of immune reactions, and protect neurons from inflammatory damage. In our study, we selected plants of the Malaysian rain forest by an ethnobotanic survey, and investigated them in cell-based-assay- systems and in living brain tissue cultures in order to identify anti-inflammatory and neuroprotective effects. We found that alcoholic extracts from the tropical plant Knema laurina (Black wild nutmeg) exhibited highly anti-inflammatory and neuroprotective effects in cell culture experiments, reduced NO- and IL-6-release from activated microglia cells dose-dependently, and protected living brain tissue from microglia-mediated inflammatory damage at a concentration of 30 µg/ml. On the intracellular level, the extract inhibited ERK-1/2- phosphorylation, IkB-phosphorylation and subsequently NF-kB-translocation in microglia cells. K. laurina belongs to the family of Myristicaceae, which have been used for centuries for treatment of digestive and inflammatory diseases and is also a major food plant of the Giant Hornbill. Moreover, extract from K. laurina promotesalso neurogenesis in living braintissue afteroxygen-glucose deprivation. In conclusion, extract from K. laurina not only controls and limits inflammatory reaction after primary neuronal damage, it promotes moreover neurogenesis if given hours until days after stroke-like injury.

The major alkaloids present in very young leaves of Mitragyna speciosa from Malaysia were shown to be highly conjugated indoles, mitragynaline and corynantheidaline. Related compounds are also present in smaller amounts and two others were isolated and characterized (named mitragynalinic acid and corynantheidalinic acid). Mitragynaline is also present as a minor component in mature leaves of the plant.

Inflammatory reactions in the CNS, resulting from a loss of control and involving a network of non-neuronal and neuronal cells, are major contributors to the onset and progress of several major neurodegenerative diseases. Therapeutic strategies should therefore keep or restore the well-controlled and finely-tuned balance of immune reactions, and protect neurons from inflammatory damage. In our study, we selected plants of the Malaysian rain forest by an ethnobotanic survey, and investigated them in cell-based-assay-systems and in living brain tissue cultures in order to identify anti-inflammatory and neuroprotective effects. We found that alcoholic extracts from the tropical plant Knema laurina (Black wild nutmeg) exhibited highly anti-inflammatory and neuroprotective effects in cell culture experiments, reduced NO- and IL-6-release from activated microglia cells dose-dependently, and protected living brain tissue from microglia-mediated inflammatory damage at a concentration of 30 microg/ml. On the intracellular level, the extract inhibited ERK-1/2-phosphorylation, IkB-phosphorylation and subsequently NF-kB-translocation in microglia cells. K. laurina belongs to the family of Myristicaceae, which have been used for centuries for treatment of digestive and inflammatory diseases and is also a major food plant of the Giant Hornbill. Moreover, extract from K. laurina promotes also neurogenesis in living brain tissue after oxygen-glucose deprivation. In conclusion, extract from K. laurina not only controls and limits inflammatory reaction after primary neuronal damage, it promotes moreover neurogenesis if given hours until days after stroke-like injury.

A new methylated flavonol, 5,7,2 ′,4 ′-tetrahydroxy-3-methoxyflavone (1), had been isolated from the methanol extract of the wood of Morus australis, along with nine known compounds, kuwanon C (2), morusin (3), morachalcone A (4), oxyresveratrol (5), 4 ′-(2-methyl-2-buten- 4-yl)oxyresveratrol (6), moracins M (7) and C (8), alboctalol (9), and macrourin B (10). The structures of these compounds were determined based on spectral evidence, including UV, IR, NMR, and mass spectra. Cytotoxic properties of compounds 1 →10 were evaluated against murine leukemia P-388 cells. The prenylated stilbene 6 and 2-arylbenzofuran 8, and morusin (3) were found to have strong cytotoxic effects with IC50 values of 6.9, 8.7, and 10.1 μM, respectively.

A new oligostilbenoid derivative, diptoindonesin F (1), along with five known oligostilbenoids, (-)-ampelopsin A (2), (-)-alpha-viniferin (3), ampelopsin E (4), (-)-vaticanol B (5), and (-)-hemsleyanol D (6), were isolated from the methanol extract of the tree bark of Shorea gibbosa. The structure of the new compound was determined based on the analysis of spectroscopic data, including UV, IR, NMR 1-D and 2-D, and mass spectra. Cytotoxic properties of the isolated oligostilbenoids were evaluated against murine leukemia P-388 cells with the result that compounds 2 and 4 showed the highest cytotoxicity.

In the search for agents effective against immune-mediated disorders and inflammation, we have screened Malaysian medicinal plants for the ability to inhibit the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on the surface of murine endothelial cells (F-2), and mouse myeloid leukaemia cells (M1), respectively. Of 41 kinds (29 species, 24 genera, 16 families) of Malaysian plants tested, 10 and 19 plant samples significantly downregulated the expression of ICAM-1 and VCAM-1, respectively. Bioassay-directed fractionation of an extract prepared from the bark of Goniothalamus andersonii showed that its ingredients, goniothalamin (1) and goniodiol (2) inhibited the cell surface expression of both ICAM-1 and VCAM-1. The present results suggest that Malaysian medicinal plants may be abundant natural resources for immunosuppressive and antiinflammatory substances.

Three new indole alkaloids with methyl chanofruticosinates skeletal system, viz., methyl 12-methoxy-N1-decarbomethoxychanofruticosinate, methyl 12-methoxychanofruticosinate and methyl 11,12-dimethoxychanofruticosinate, in addition to methyl 11, 12-methylenedioxy-N1-decarbomethoxychanofruticosinate, have been isolated from the leaves of Kopsia flavida Blume. The structures of these three new indole alkaloids were assigned by NMR spectral data using various 2D-techniques.

In the title compound, C12H15NO3, the iso­quinoline moiety is essentially planar, except for the N and adjacent Csp3 atoms, which deviate from the mean plane by 0.198 (2) and 0.686 (2) A, respectively. The bond length between the N and carbonyl C atoms [1.353 (3) A] is close to a double-bond value, indicating electron delocalization. No significant intermolecular interactions are observed.

A new 2-arylbenzofuran derivative (diptoindonesin G) (1), along with nine known oligostilbenes, have been isolated and identified from the acetone extract of the tree bark of Hopea mengarawan. The structures of these compounds were determined based on spectroscopic data, including 2D NMR and HREIMS spectra. On cytotoxic evaluation of the isolated compounds against murin leukemia P-388 cells, compound 1 was the strongest in inhibiting the growth of the cells.

Two prenylated dihydrostilbenes have been isolated from the methanol extract of the flower of Croton laevifolius. The structures of these compounds were assigned as 3,5,3′,4′-tetrahydroxy-2,6,2′-tris(3-methylbut-2-enyl)dihydrostilbene (laevifolin A) and 3,5,3′,4′-tetrahydroxy-2,6,5′-tris(3-methylbut-2-enyl)dihydrostilbene (laevifolin B) based on spectroscopic evidence, including UV, IR, 1D and 2D NMR, and mass spectra. The chemotaxonomic significance of the presence of these dihydrostilbene derivatives is briefly discussed.

A new alkaloid, 4'-hydroxy-3', 5'-dimethoxybenzoylvincamajine [1], was isolated with nine known alkaloids from the roots of Alstonia angustifolia (Apocynaceae)

An investigation of the fresh leaves of Mitragyna speciosa has resulted in the isolation of a new alkaloid in addition to the indole alkaloids previously reported. The new alkaloid is the 3-dehydro derivative of mitragynine and its structure was elucidated by spectral means and chemical transformations. (-)-Epicatechin was also isolated from the leaves.