Isolation of new phytometabolites from Alpinia galanga willd rhizomes.

The current research was aimed to isolate newer phyto-metabolites from rhizomes of Alpinia galanga plant. Study involved preparation of Alpinia galanga rhizome methanolic extract, followed by normal phase column chromatography assisted isolation of new phytometabolites (using different combinations of chloroform and methanol), and characterization (by UV, FTIR, 13C-NMR, 1H-NMR, COSY, DEPT and Mass spectrometry). The isolation and characterization experiment offered two phytometabolites: an ester (Ag-1) and tetrahydronapthalene type lactone (Ag-2). Present study concludes and reports the two phytometabolites, benzyl myristate (Ag-1) and 3-Methyl-6α, 8ß-diol-7-carboxylic acid tetralin-11, 9ß-olide (Ag-2) for the first time in Alpinia galanga rhizome. The study recommends that these phytometabolites Ag-1 and Ag-2 can be utilized as effective analytical biomarkers for identification, purity and quality control of this plant in future.

Peak AAA fatty acid homolog contaminants present in the dietary supplement l-Tryptophan associated with the onset of eosinophilia-myalgia syndrome.

The eosinophilia-myalgia syndrome (EMS) outbreak that occurred in the USA and elsewhere in 1989 was caused by the ingestion of Showa Denko K.K. (SD) L-tryptophan (L-Trp). "Six compounds" detected in the L-Trp were reported as case-associated contaminants. Recently the final and most statistically significant contaminant, "Peak AAA" was structurally characterized. The "compound" was actually shown to be two structural isomers resulting from condensation reactions of L-Trp with fatty acids derived from the bacterial cell membrane. They were identified as the indole C-2 anteiso (AAA1-343) and linear (AAA2-343) aliphatic chain isomers. Based on those findings, we utilized a combination of on-line HPLC-electrospray ionization mass spectrometry (LC-MS), as well as both precursor and product ion tandem mass spectrometry (MS/MS) to facilitate identification of a homologous family of condensation products related to AAA1-343 and AAA2-343. We structurally characterized eight new AAA1-XXX/AAA2-XXX contaminants, where XXX represents the integer molecular ions of all the related homologs, differing by aliphatic chain length and isomer configuration. The contaminants were derived from the following fatty acids of the bacterial cell membrane, 5-methylheptanoic acid (anteiso-C8:0) for AAA1-315; n-octanoic acid (n-C8:0) for AAA2-315; 6-methyloctanoic acid (anteiso-C9:0) for AAA1-329; n-nonanoic acid (n-C9:0) for AAA2-329; 10-methyldodecanoic acid (anteiso-C13:0) for AAA1-385; n-tridecanoic acid (n-C13:0) for AAA2-385; 11-methyltridecanoic acid (anteiso-C14:0) for AAA1-399; and n-tetradecanoic acid (n-C14:0) for AAA2-399. The concentration levels for these contaminants were estimated to be 0.1-7.9 µg / 500 mg of an individual SD L-Trp tablet or capsule The structural similarity of these homologs to case-related contaminants of Spanish Toxic Oil Syndrome (TOS) is discussed.

Methyl 3-Hydroxymyristate, a Diffusible Signal Mediating phc Quorum Sensing in Ralstonia solanacearum.

Ralstonia solanacearum, a plant pathogenic bacterium causing "bacterial wilt" on crops, uses a quorum sensing (QS) system consisting of phc regulatory elements to control its virulence. Methyl 3-hydroxypalmitate (3-OH PAME) was previously identified as the QS signal in strain AW1. However, 3-OH PAME has not been reportedly detected from any other strains, and this suggests that they produce another unknown QS signal. Here we identify (R)-methyl 3-hydroxymyristate [(R)-3-OH MAME] as a new QS signal that regulates the production of virulence factors and secondary metabolites. (R)-3-OH MAME was synthesized by the methyltransferase PhcB and sensed by the histidine kinase PhcS. The phylogenetic trees of these proteins from R. solanacearum strains were divided into two groups, according to their QS signal types--(R)-3-OH MAME or (R)-3-OH PAME. These results demonstrate that (R)-3-OH MAME is another crucial QS signal and highlight the unique evolution of QS systems in R. solanacearum.

seco-Abietane diterpenoids, a phenylethanoid derivative, and antitubercular constituents from Callicarpa pilosissima.

Six new compounds, including five new seco-abietane diterpenoids, 12-deoxy-seco-hinokiol methyl ester (1), 12-deoxy-11,12-dihydro-seco-hinokiol methyl ester (2), callicarpic acid A (3), 9alpha-hydroxycallicarpic acid A (4), and callicarpic acid B (5), and a new phenylethanoid derivative, 4-hydroxyphenethyl tetradecanoate (6), have been isolated from the leaves and twigs of Callicarpa pilosissima, together with 14 known compounds (7-20). The structures of these new compounds were determined through analyses of physical data. 12-Deoxy-11,12-dihydro-seco-hinokiol methyl ester (2), callicarpic acid B (5), and alpha-tocopherol trimer B (15) exhibit antitubercular activities (MICs

Secondary metabolites from endophytic Streptomyces sp. Lz531.

From the branch tissue of Maytenus hookeri, the endophytic strain Lz531 was isolated, and determined to belong to Streptomyces, according to its 16S rRNA sequence. From the extracts of the fermentation broth of Streptomyces sp. Lz531, two new and four known compounds were isolated. The two new compounds were identified as cyclo(L-Pro-L-Val-L-Val) (1) and 13-methyl-N-(2-phenylethyl)tetradecanamide (2).

Single-step purification of myristoylated and nonmyristoylated recoverin and substrate dependence of myristoylation level.

Recoverin is cotranslationally modified by the covalent linkage of a myristoyl group to its N terminus. It is a member of a family of Ca(2+)-myristoyl switch proteins. Recombinant myristoylated revoverin is currently produced by the cotransformation of bacteria with recoverin and an enzyme that allows N-myristoylation and by supplementing the culture medium with myristic acid. A large variation in the myristoylation level of recoverin and in the amount of myristic acid supplied to the culture medium can be found in the literature. Moreover, although it is known to strongly affect bacterial growth, the amount of ethanol used to solubilize myristic acid is only scarcely mentioned. To improve our understanding of the parameters responsible for recombinant recoverin myristoylation, the effects of myristic acid and ethanol on recoverin myristoylation and expression levels have been systematically studied. In addition, a single-step purification procedure to produce purified myristoylated and nonmyristoylated recombinant recoverin has also been devised. Finally, sodium myristate has been used as an efficient alternative substrate to achieve high myristoylation and expression levels of recoverin. Given that a large number of proteins are myristoylated, these procedures could be applied to several other proteins in addition to recoverin.