Halogenated acetic and acrylic acids from the red alga Asparagopsis taxiformis

Nine halogenated acetic acids and nine halogenated acrylic acids have been identified in the aqueous extract of Hawaiian Asparagopsis taxiformis.     

A halogenated chamigrane epoxide and six related halogen-containing sesquiterpenes from the red alga Laurencia okamurai

From the red alga Laurencia okamurai a new chamigrane epoxide and six known halogenated chamigranes were isolated. The structure of the new epoxide     

Terpenoids from marine red alga Laurencia pinnatifida

A new halogenated chamigrene named pinnatifenol, a rearranged chamigrene derivative a diterpenoid have been isolated from the ethyl acetate fraction of marine red alga Laurencia pinnatifida. Their structures were elucidated by spectroscopic means.     

Sesquiterpenes from the marine red alga Laurencia distichophylla

A new cuparene-type sesquiterpene, isolaurenisol, has been isolated and identified from the New Zealand red alga Laurencia distichophylla. Major differences in the chemical composition of two morphologically indistinguishable samples of L. distichophylla are noted.     

Peroxidase from the red alga Cystoclonium purpureum

A particulate peroxidase has been extracted from the marine red alga Cystoclonium parpureum. Solubilisation was achieved by the use of either digit     

Halogenated diterpenoids from the red alga Laurencia nipponica

Chemical compositions of three collections of the red alga Laurencia nipponica from the western part of the Sea of Japan were studied. One of them contained a series of the previously known sesquiterpenoids. Another one gave C15 bromoallene ethers, predominantly. Finally, two new halogenated diterpenes, 15-bromoparguer-9(11)-ene-16-ol and 15-bromoparguer-7-ene-16-ol, were isolated from the third collection of the same species. Structures of these diterpenoids were established by 1D and 2D NMR (1H-1H COSY, DEPT, HMQC, HMBC and NOESY) along with molecular calculations for conformations having lowest energies and mass spectroscopy. Diversity and variability of halogenated secondary metabolites in L. nipponica were discussed.     

Laurequinone,a cyclolaurane sesquiterpene from the red alga Laurencia nidifica

From the red alga Laurencia nidifica a new sesquiterpene of cyclolaurane-type was isolated, and the structure elucidated by spectral analyses and chemical means.     

Two new polyhalogenated monoterpenes from the red alga Plocamium cartilagineum

The structures and absolute configurations of two new halogenated alicyclic monoterpenes isolated from the ether extract of the red alga Plocamium cartilagineum (Linn) Dixon were determined as: 1R,2S,4S,5R-5-chloro-2-E-chlorovinyl-1,4-dibromo-1,5-dimethylcyclohexane and 1S,2S,4R,5S-2-bromo-1-E-bromovinyl-4,5-dichloro-1,5-dimethylcyclohexane, respectively.     

Bromo-compounds of the red alga Lenormandia prolifera

Six bromo-compounds and one bromo-chloro-compound have been detected in Lenormandia prolifera (C.Ag.) J. Agardh (Amansieae; Rhodomelaceae). Hydrolysis of the red pigment floridorubin from the same alga yielded five bromo-, one bromo-chloro and one chloro-phenol. The two main phenols of floridorubin were 2,3-dibromo-4,5-dihydroxy benzyl alcohol (lanosol) and 3,5-dibromo-p-hydroxybenzyl alcohol.     

Sulfur and N-methylformamide from the marine red alga Erythrophyllum delesserioides

Elementant S (0.2 % dry wt) and N-methylformamide (0.2 % dry wt) were isolated from the marine red alga Erythrophyllum delesserioides.     

(−)-(S)-4-dimethylsulfonio-2-methoxybutyrate from the red alga Rytiphloea tinctoria

An unusual compound (?)-(S)-4-dimethylsulfonio-2-methoxybutyrate, was identified in aqueous—ethanolic extracts of the red alga Rytiphloea tinctoria.     

A c-15 non-terpenoid from the red alga Laurencia okamurai

The structure of a new C-15 bromoallene from the red alga Laurencia okamurai was deduced by spectral methods.     

Laurebiphenyl,a dimeric sesquiterpene of the cyclolaurane-type from the red alga Laurencia nidifica

Laurebiphenyl, a new, dimeric sesquiterpene of the cyclolaurane-type, was isolated from the red alga Laurencia nidifica. Its structure was determined by spectral and chemical means.     

Antibacterial bromophenols from the marine red alga Rhodomela confervoides

Two bromophenols, together with three known compounds, were isolated from the methanolic extract of the marine alga, Rhodomela confervoides. By means of MS and NMR spectroscopic analyses, they were identified as 3-bromo-4-[2,3-dibromo-4,5-dihydroxyphenyl] methyl-5-(hydroxymethyl) 1,2-benzenediol (1) and 3-bromo-4-[2,3-dibromo-4,5-dihydroxyphenyl] methyl-5- (ethoxymethyl) 1,2-benzenediol (2). Three known compounds were also isolated, namely 3-bromo-4-[2,3-dibromo-4,5-dihydroxyphenyl] methyl-5-(methoxymethyl) 1,2-benzenediol (3), 4,4'- methylenebis [5,6-dibromo-1,2-benzenediol] (4) and bis (2,3-dibromo-4,5-dihydroxybenzyl) ether (5). Compound 5 was the most active against five strains of bacteria with the MIC less than 70 microg/ml, while compounds 2, 3 and 4 exhibited moderate activity.     

Metabolism of 4-hydroxybenzaldehyde, 3-bromo-4-hydroxybenzaldehyde and bromide by cell-free fractions of the marine red alga Odonthalia floccosa

Cell-free fractions from Odonthalia floccosa incubated with 4-hydroxybenzaldehyde-[U-¹⁴C], 3-bromo-4-hydroxybenzaldehyde-[U-¹⁴C] and ⁸²Br^? formed the dibromo-dihydroxybenzaldehyde derivatives of the bromophenols (brominated benzylalcohols) which were also identified as naturally occurring products.     

Generation of 10,154 expressed sequence tags from a leafy gametophyte of a marine red alga, Porphyra yezoensis.

A total of 10,154 5'-end expressed sequence tags (EST) were established from the normalized and size-selected cDNA libraries of a marine red alga, Porphyra yezoensis. Among the ESTs, 2140 were unique species, and the remaining 8014 were grouped into 1127 species. Database search of the 3267 non-redundant ESTs by BLAST algorithm showed that the sequences of 1080 species (33.1%) have similarity to those of registered genes from various organisms including higher plants, mammals, yeasts, and cyanobacteria, while 2187 (66.9%) are novel. Codon usage analysis in the coding regions of 101 non-redundant EST groups showing significant similarity to known genes indicated the higher GC contents at the third position of codons (79.4%) than the first (62.2%) and the second position (45.0%), suggesting that the genome has been exposed to high GC pressure during evolution. The sequence data of individual ESTs are available at the web site http://www.kazusa.or.jp/en/plant/porphyra/EST/.     

A new isolation procedure and further characterisation of the lectin from the red marine alga Ptilota serrata

Ptilota serrata has been shown previously to contain a lectin (PSL) which is non-specific for human blood groups. We report here a new isolation procedure for PSL using a single step affinity chromatography technique on cross-linked guar gum and further characterisation studies. PSL was inhibited by galactose and its derivatives. The carbohydrates o-nitrophenyl-N-acetyl-α-D-galactoside, p-nitrophenyl-N-acetyl-β-D-galactoside and lactose were strong inhibitors. The glycoproteins porcine stomach mucin, asialo bovine mucin and asialofetuin were also inhibitory. The Mr of PSL, determined by gel filtration, was 55,470. SDS-PAGE revealed one single protein band with Mr of 18,390, indicating the native protein to be a trimer of apparently identical subunits. PSL was shown to contain large amounts of acidic and hydroxyl amino acids but low in basic amino acids. This revised version was published online in August 2006 with corrections to the Cover Date.     

Sesquiterpenes from the red alga Laurencia tristicha

Phytochemical investigation on Laurencia tristicha afforded eleven cuparane-derived sesquiterpenes, including ten monomers and one dimer, and their structures were elucidated by a combination of spectroscopic analysis and comparison with those reported in literature. Four compounds, laurinterol acetate, debromolaurinterol acetate, aplysinal, and (−)-α-bromocuparene were obtained from L. tristicha for the first time. Additionally, the chemotaxonomic significance of these cuparane-derived sesquiterpenes, as well as their plausible biogenetic pathway, was also discussed.