Methylated anthocyanidin glycosides from flowers of Canna indica

Methylated anthocyanin glycosides were isolated from red Canna indica flower and identified as malvidin 3-O-(6-O-acetyl-β-d-glucopyranoside)-5-O-β-d-glucopyranoside (1), malvidin 3,5-O-β-d-diglucopyranoside (2), cyanidin-3-O-(6″-O-α-rhamnopyranosyl-β-glucopyranoside (3), cyanidin-3-O-(6″-O-α-rhamnopyranosyl)-β-galactopyranoside (4), cyanidin-3-O-β-glucopyranoside (5) and cyanidin-O-β-galactopyranoside (6) by HPLC-PDA. Their structures were subsequently determined on the basis of spectroscopic analyses, that is, ¹H NMR, ¹³C NMR, HMQC, HMBC, ESI-MS, and UV-vis. Compounds (1-4) were found to be in major quantity while compounds (5-6) were in minor quantity.     

Inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 macrophage cells by lignans isolated from Euonymus alatus leaves and twigs

The 80% methanolic extract of Euonymus alatus leaves and twigs afforded three new lignans, (−)-threo-4,9,4′,9′-tetrahydroxy-3,7,3′,5′-tetramethoxy-8-O-8′-neolignan (1), (−)-threo-4,9,4′,9′-tetrahydroxy-3,5,7,3′-tetramethoxy-8-O-8′-neolignan (2), (7R,8R,7′R)-(+)-lyoniresinol (3), together with seventeen known lignans (4-20). The structures of 1-20 were elucidated by extensive 1D and 2D spectroscopic methods including ¹H NMR, ¹³C NMR, ¹H-¹H COSY, HMQC, HMBC and NOESY. All the isolated compounds except for dilignans (19 and 20) significantly inhibited nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells.     

Phytoconstituents from the root of Streptocaulon tomentosum and their chemotaxonomical relevance for separation from S. juventas

A new cardenolide, 17β-H-periplogenin-3-O-β-d-digitoxoside (1), and a new pregnane glycoside, Δ⁵-pregnene-3β,16α-diol-d-O-[2,4-O-diacetyl-β-digitalopyranosyl-(1 → 4)-β-d-cymaropyranoside]-16-O-[β-d-glucopyranoside] (2) were isolated from the roots of Streptocaulon tomentosum (Asclepiadaceae) together with a series of known compounds. Their chemotaxonomic significance for the separation of S. tomentosum from Streptocaulon juventas is discussed, suggesting a rather clear distinction of these species.     

Anthocyanins in Caprifoliaceae

The qualitative and relative quantitative anthocyanin content of 19 species belonging to the genera Sambucus, Lonicera and Viburnum in the family Caprifoliaceae has been determined. Altogether 12 anthocyanins were identified; the 3-O-glucoside (2), 3-O-galactoside (5), 3-O-(6″-O-arabinosylglucoside) (7), 3-O-(6″-O-rhamnosylglucoside) (9), 3-O-(2″-O-xylosyl-6″-O-rhamnosylglucoside) (10), 3-O-(2″-O-xylosylgalactoside) (11), 3-O-(2″-O-xylosylglucoside) (12), 3-O-(2″-O-xylosylglucoside)-5-O-glucoside (14), 3-O-(2″-O-xylosyl-6″-O-Z-p-coumaroylglucoside)-5-O-glucoside (15) and 3-O-(2″-O-xylosyl-6″-O-E-p-coumaroylglucoside)-5-O-glucoside (16) of cyanidin, in addition to the 3-O-glucosides of pelargonidin and delphinidin (1 and 3). Pigment 7 is the first complete identification of the disaccharide vicianose, 6″-O-α-arabinopyranosyl-β-glucopyranose, linked to an anthocyanidin.     

Acylated flavonol tetraglycosides from Delphinium gracile

An ethanol extract of the aerial parts of Delphinium gracile DC. yielded five flavonol glycosides quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(E-p-caffeoyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (1), quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (2), quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(Z-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (3), kaempferol-3-O-{[β-d-glucopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranoside-7-O-(4-O-acetyl)-α-l-rhamnopyranoside (4) kaempferol-3-O-{[β-d-glucopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranoside-7-O-(4-O-acetyl)-α-l-rhamnopyranoside (5) in addition to 4-(β-d-glucopyranosyloxy)-6-methyl-2H-pyran-2-one (6) and rutin. Structures were elucidated by spectroscopic methods.     

Isolation and structure of d-xylans from pericarp seeds of Opuntia ficus-indica prickly pear fruits

Xylans were isolated from the pericarp of prickly pear seeds of Opuntia ficus-indica (OFI) by alkaline extraction, fractionated by precipitation and purified. Six fractions were obtained and characterized by sugar analysis and NMR spectroscopy. They were assumed to be (4-O-methyl-d-glucurono)-d-xylans, with 4-O-α-d-glucopyranosyluronic acid groups linked at C-2 of a (1→4)-β-d-xylan. The sugar composition and the ¹H and ¹³C NMR spectra showed that their chemical structures were very similar, but with different proportions of d-Xyl and 4-O-Me-d-GlcA. Our results showed that, on average, the water soluble xylans have one nonreducing terminal residue of 4-O-methyl-d-glucuronic acid for every 11 to 14 xylose units, whereas in the water non-soluble xylans, xylose units can varied from 18 to 65 residues for one nonreducing terminal residue of 4-O-methyl-d-glucuronic acid.     

Bicarbonate use in three aquatic plants

Our study aimed to test the ability of aquatic plants to use bicarbonate when acclimated to three different bicarbonate concentrations. To this end, we performed experiments with the three species Ceratophyllum demersum, Egeria densa, Lagarosiphon major to determine photosynthetic rates under varying bicarbonate concentrations. We measured bicarbonate use efficiency, photosynthetic performance and respiration. For all species, our results revealed that photosynthetic rates were highest in replicates grown at low alkalinity. Thus, E. densa had approx. five times higher rates at low (264 ± 15 μmol O₂ g⁻¹ DW h⁻¹) than at high alkalinity (50 ± 27 μmol O₂ g⁻¹ DW h⁻¹), C. demersum had three times higher rates (336 ± 95 and 120 ± 31 μmol O₂ g⁻¹ DW h⁻¹), and L. major doubled its rates at low alkalinity (634 ± 114 and 322 ± 119 μmol O₂ g⁻¹ DW h⁻¹). Similar results were obtained for bicarbonate use efficiency by E. densa (136 ± 44 and 43 ± 10 μmol O₂ mequiv. L⁻¹ g⁻¹ DW h⁻¹) and L. major (244 ± 29 and 82 ± 24 μmol O₂ mequiv. L⁻¹ g⁻¹ DW h⁻¹). As to C. demersum, efficiency was high but unaffected by alkalinity, indicating high adaptation ability to varied alkalinities. A pH drift experiment supported these results. Overall, our results suggest that the three globally widespread worldwide species of our study adapt to low inorganic carbon availability by increasing their efficiency of bicarbonate use.     

Galactans from Cryptonemia species. Part II: Studies on the system of galactans of Cryptonemia seminervis (Halymeniales) and on the structure of major fractions

Cryptonemia seminervis biosynthesizes a family of d,l-hybrid galactans based on the classical 3-linked β-d-galactopyranosyl→4-linked α-d- and α-l-galactopyranosyl alternating sequence (A-units→B-units) with major amounts of α-d- and α-l-galactose and 3,6-anhydro-d- and l-galactose and lesser percentages of 3,6-anhydro-2-O-methyl-l-galactose, 2-O-methyl-, 4-O-methyl- and 6-O-methylgalactoses. The dispersion of structures in this family is based on five structural factors, namely: (a) the amount and position of substituent groups as sulfate (major), pyruvic acid ketals, methoxyl and glycosyl side-chain (4-O-methyl galactopyranosyl and/or xylosyl); (b) the ratio galactose/3,6-anhydrogalactose in the B-units; (c) the ratio d,l-galactoses and d,l-3,6-anhydrogalactoses also in the B-units, (d) the formation of diads and (e) the sequence of the diads in the linear backbone. Considering these variables it is not unexpected to find in the fractions studied at least 18 structural units producing highly complex structures. Structural studies carried out in two major fractions (S2S-3 and S2S-4) showed that these galactans were formed mainly by β-d-galactopyranosyl 2-sulfate (20 and 11.9 mol %), β-d-galactopyranosyl 2-sulfate 4,6-O-(1′-carboxyethylidene) (8.9 and 6.0 mol %) and β-d-galactopyranosyl 2,6-sulfate (5.4 and 18.6 mol %), together with 3,6-anhydro-α-l-galactopyranosyl (11.4 and 7.3 mol %) and 3,6-anhydro-α-l-galactopyranosyl 2-sulfate (4.9 and 15.4 mol %) and minor quantities of 12-15 other structural units.Preparative alkaline treatment carried out on fraction (S2S-3) produced a quantitative formation of 3,6-anhydro α-l-galactopyranosyl units from precursor units (α-l-galactose 6-sulfate and α-l-galactose 2,6-sulfate). Kinetic studies on this 3,6-anhydro cyclization show a rate constant of 5.2 × 10⁴ s⁻¹ indicating diads of the type G→L6S/2,6S. Data from chemical, spectroscopic and kinetic studies suggest that, in S2S-3, the agaran block in the d,l-hybrid galactan is composed of the following diads: G(6R)→L6S/2,6S and G2S(P)(2,6S)→LA(2S)(2R)(2M) and the carrageenan block of G2S(P)→D(2S)(2,3S)(3S)(3,6S) in a molar ratio of agaran to carrageenan structures of ∼2:1.     

Short term effects of hypoxia and bioturbation on solute fluxes, denitrification and buffering capacity in a shallow dystrophic pond

The effects of short term hypoxia on bioturbation activity and inherent solute fluxes are scarcely investigated even if increasing number of coastal areas are subjected to transient oxygen deficits. In this work dark fluxes of oxygen (O₂), dissolved inorganic carbon (TCO₂) and nutrients across the sediment-water interface, as well as rates of denitrification (isotope pairing), were measured in intact sediment cores collected from the dystrophic pond of Sali e Pauli (Sardinia, Italy). Sediments were incubated at 100, 70, 40 and 10% of O₂ saturation in the overlying water, with both natural benthic communities, dominated by the polychaete Polydora ciliata (11.100 ± 2.500  ind. m^− 2), and after the addition of individuals of the deep-burrower polychaete Hediste diversicolor. Below an uppermost oxic layer of ~ 1 mm, sediments were highly reduced, with up to 6 mM of S²⁻ in the 5 mm layer. Flux of S²⁻ and O₂ calculated from pore water gradients were 8.61 ± 1.12 and − 2.27 ± 0.56 mmol m^− 2 h^− 1, respectively. However, sediment oxygen demand (SOD) calculated from core incubation was − 10.52 ± 0.33 mmol m^− 2 h^− 1, suggesting a major contribution of P. ciliata to O₂-mediated sulphide oxidation. P. ciliata also strongly stimulated NH₄⁺ and PO₄³⁻ fluxes, with rates ~ 15 and ~ 30 folds higher, respectively, than those estimated from pore water gradients. P. ciliata activity was significantly reduced at 10% O₂ saturation, coupled to decreased rates of solutes transfer. The addition of H. diversicolor further stimulated SOD, NH₄⁺ efflux and SiO₂ mobilisation. Similarly to P. ciliata, the degree of stimulation of SOD and NH₄⁺ flux by H. diversicolor depended on the level of oxygen saturation. TCO₂ regeneration, respiratory quotients, PO₄³⁻ fluxes and denitrification of added ¹⁵NO₃⁻ were not affected by the addition of H. diversicolor, but depended upon the O₂ levels in the water column. Denitrification rates supported by water column ¹⁴NO₃⁻ and sedimentary nitrification were both negligible (< 0.5 µmol m^− 2 h^− 1). They were not significantly affected by oxygen saturation nor by bioturbation, probably due to the limited availability of NO₃⁻ in the water column (< 3 µM) and O₂ in the sediments. This study demonstrates for the first time the integrated short term effect of transient hypoxia and bioturbation on solute fluxes across the sediment-water interface within a simplified lagoonal benthic community.     

Steroidal saponins from the leaves of Beaucarnea recurvata

Thirteen steroidal saponins were isolated from the leaves of Beaucarnea recurvata Lem. Their structures were established using one- and two-dimensional NMR spectroscopy and mass spectrometry. Six of them were identified as: 26-O-β-d-glucopyranosyl (25S)-furosta-5,20(22)-diene 1β,3β,26-triol 1-O-α-l-rhamnopyranosyl-(1 → 2) β-d-fucopyranoside, 26-O-β-d-glucopyranosyl (25S)-furosta-5,20(22)-diene 1β,3β,26-triol 1-O-α-l-rhamnopyranosyl-(1 → 2)-4-O-acetyl-β-d-fucopyranoside, 26-O-β-d-glucopyranosyl (25R)-furosta-5,20(22)-diene-23-one-1β,3β,26-triol 1-O-α-l-rhamnopyranosyl-(1 → 2) β-d-fucopyranoside, 26-O-β-d-glucopyranosyl (25S)-furosta-5-ene-1β,3β,22α,26-tetrol 1-O-α-l-rhamnopyranosyl-(1 → 4)-6-O-acetyl-β-d-glucopyranoside, 26-O-β-d-glucopyranosyl (25S)-furosta-5-ene-1β,3β,22α,26-tetrol 1-O-α-l-rhamnopyranosyl-(1 → 2) β-d-fucopyranoside, and 24-O-β-d-glucopyranosyl (25R)-spirost-5-ene-1β,3β,24-triol 1-O-α-l-rhamnopyranosyl-(1 → 2)-4-O-acetyl-β-d-fucopyranoside. The chemotaxonomic classification of B. recurvata in the family Ruscaceae was discussed.     

Iridoids from Gentiana loureirii

Iridoid glycosides, 2′,3′,6′-tri-O-acetyl-4′-O-trans-p-(O-β-d-glucopyranosyl)coumaroyl-7-ketologanin (1), 2′-O-caffeoylloganic acid (2), 2′-O-p-hydroxybenzoylloganic acid (3), 2′-O-trans-p-coumaroylloganic acid (4), and 2′-O-cis-p-coumaroylloganic acid (5), were isolated from whole plants of Gentiana loureirii along with six known iridoids, 7-ketologanin (6), loganin (7), loganic acid (8), sweroside, boonein, and isoboonein, and three other known compounds. Their structures were elucidated by spectroscopic means and chemical correlations. The isolated iridoids were evaluated for antibacterial and antioxidant activities, but were either inactive or very weakly active.     

Au(III)-complexes of the alanyl-containing peptides glycylalanine and glycylalanylalanine - Synthesis, spectroscopic and structural characterization

As part of an investigation on the coordination ability of peptides, the dipeptide glycylalanine (H-Gly-Ala-OH), tripeptide glycylalanylalanine (H-Gly-Ala-Ala-OH) and their Au(III)-complexes have been characterized structurally. The quantum chemical calculations and linear-dichroic infrared (IR-LD) spectroscopy predict structures of the compound studied, which are compared with a single crystal X-ray diffraction of H-Gly-Ala-OH. The coordination processes with Au(III) are supported by data for ¹H NMR, ESI-MS, HPLC-MS-MS, TGV and DSC methods. The [Au(Gly-Ala)H₋₁Cl] and [Au(Gly-Ala-Ala)H₋₂] · 2H₂O complexes are formed via -NH₂, N⁻amide/s and groups of the peptides. One Cl⁻ ion is attached to the metal center as terminal ligand in the first complex. In both cases a near to square-planar geometry of the chromophors AuN₂OCl and AuN₃O is yielded.     

Metabolomics-oriented isolation and structure elucidation of 37 compounds including two anthocyanins from Arabidopsis thaliana

In order to conduct metabolomic studies in a model plant for genome research, such as Arabidopsis thaliana (Arabidopsis), it is a prerequisite to obtain structural information for the isolated metabolites from the plant of interest. In this study, we isolated metabolites of Arabidopsis in a relatively non-targeted way, aiming at the construction of metabolite standards and chemotaxonomic comparison. Anthocyanins (5 and 7) called A8 and A10 were isolated and their structures were elucidated as cyanidin 3-O-[2-O-(β-d-xylopyranosyl)-6-O-(4-O-(β-d-glucopyranosyl)-E-p-coumaroyl)-β-d-glucopyranoside]-5-O-[6-O-(malonyl)-β-d-glucopyranoside] and cyanidin 3-O-[2-O-(2-O-(E-sinapoyl)-β-d-xylopyranosyl)-6-O-(4-O-(β-d-glucopyranosyl)-E-p-coumaroyl)-β-d-glucopyranoside]-5-O-[β-d-glucopyranoside] from analyses of 1D NMR, 2D NMR (¹H NMR, NOE, ¹³C NMR, HMBC and HMQC), HRFABMS, FT-ESI-MS and GC-TOF-MS data. In addition, 35 known compounds, including six anthocyanins, eight flavonols, one nucleoside, one indole glucosinolate, four phenylpropanoids and a derivative, together with three indoles, one carotenoid, one apocarotenoid, three galactolipids, two chlorophyll derivatives, one steroid, one hydrocarbon, and two dicarboxylic acids, were also isolated and identified from their spectroscopic data.     

Flavones and flavone glycosides from Halophila johnsonii

Halophila johnsonii Eiseman is a shallow-water marine angiosperm which contains UV-absorbing metabolites. Studies on methanol extracts of H. johnsonii by means of HPLC-UV, NMR, HPLC-MS resulted in isolation and identification of seven previously unknown flavone glycosides: 5,6,7,3′,4′,5′-hexahydroxyflavone-7-O-β-glucopyranoside (1), 5,6,7,3′,4′,5′-hexahydroxyflavone-7-O-(6″-O-acetyl)-β-glucopyranoside (2), 6-hydroxyluteolin-7-O-(6″-O-acetyl)-β-glucopyranoside (3), 6-hydroxyapigenin-7-O-(6″-O-acetyl)-β-glucopyranoside (4), 6-hydroxyapigenin-7-O-(6″-O-[E]-coumaroyl)-β-glucopyranoside (5), 6-hydroxyapigenin-7-O-(6″-O-[E]-caffeoyl)-β-glucopyranoside (6) and 6-hydroxyluteolin-7-O-(6″-O-[E]-coumaroyl)-β-glucopyranoside (7). Also isolated were three known flavone glycosides, 6-hydroxyluteolin 7-O-β-glucopyranoside (8), scutellarein-7-O-β-glucopyranoside (9), and spicoside (10), and five known flavones, pedalitin (11), ladanetin (12), luteolin (13), apegenin (14) and myricetin (15). Qualitative comparison of the flavonoid distribution in the leaf and rhizome-root portions of the plant was also investigated, with the aim of establishing the UV-protecting roles that flavonoids played in the sea grass.     

Purification and structural investigation of a water-soluble polysaccharide from Flammulina velutipes

A novel water-soluble heteropolysaccharide FVP60-B was extracted from the fruiting bodies of Flammulina velutipes with boiling water and purified by Sephacryl S-300 and S-400, which molecular weight was estimated to be 1.3 × 10⁴ Da by HPLC. It is composed of l-fucose, d-mannose, d-glucose and d-galactose in a ratio of 1.16:0.82:1.00:3.08. Sugar analysis, methylation analysis together with ¹H, ¹³C and 2D NMR spectroscopy disclosed that FVP60-B is consisted of a α-(1 → 6)-d-galactopyranan backbone with a terminal fucosyl, terminal glucosyl and α-(1 → 6)-d-mannopyranan units on O-2 of 2,6-O-substituted-d-galactosyl units.     

Flavonoid profiles in the Heliohebe group of New Zealand Veronica (Plantaginaceae)

The Heliohebe group of Veronica (sect. Hebe) consists of five species occurring in the South Island of New Zealand. These species and a hybrid were analysed for their flavonoids. Five flavone glycosides were isolated and identified by NMR spectroscopy and three additional glycosides were detected by LC–UV–MS. Luteolin 7-O-, 3′-O- and 4′-O-glucosides and apigenin 7-O-glucoside were present in all six taxa investigated, 6-hydroxyluteolin glycosides were found in five and a luteolin caffeoylglycoside in four taxa, while a hypolaetin 7-O-glycoside was detected only in Veronica pentasepala. The 3′-O- and 4′-O-glucosides of luteolin are also common in other species of Veronica sect. Hebe (restricted to the Southern Hemisphere), but are rare in Northern Hemisphere species of Veronica and thus act as good chemotaxonomic markers for the section. The relatively simple flavonoid profiles found in the Heliohebe group are plesiomorphic and consistent with the group's status as sister to the Hebe clade. Based on the detected flavonoids, two groups could be distinguished within the Heliohebe clade: (1) Veronica hulkeana, Veronica lavaudiana and Veronica raoulii, characterised by luteolin caffeoylglycoside, and (2) V. pentasepala and Veronica scrupea, where this compound is replaced by a 6-hydroxyluteolin dihexoside.     

Potential allelopatic effects of stilbenoids and flavonoids from leaves of Carex distachya Desf.

The potential allelopathic effects of 14 stilbenoids and five flavonoids, isolated from leaves of Carex distachya Desf., were evaluated on the seed germination and seedling growth of three coexisting Mediterranean species (Dactylis hispanica, Petrorhagia velutina, and Phleum subulatum). The structures of the metabolites have been elucidated on the basis of their spectroscopic features (1D and 2D NMR experiments and EI–MS and ESI–MS data). The bioassays showed species-specific effects of the metabolites from C. distachya, specially on the plant growth (root and shoot elongation) which resulted significantly stimulated or inhibited at 10⁻⁴ M concentration. The effects on root elongation is generally greater than the shoot growth at all the tested concentrations (10⁻⁴–10⁻⁸ M). Cluster of biological data showed interesting relationships between the chemical structures of the compounds and their biological effects.     

Accumulation of lead by free and immobilized cyanobacteria with special reference to accumulation factor and recovery

Lead accumulation by free and immobilized cyanobacteria, Lyngbya majuscula and Spirulina subsalsa was studied. Exponentially growing biomass was exposed to 1-20 mg L⁻¹ of Pb(II) solution at pH 6, 7 and 8 for time periods ranging from 10 min to 48 h. L. majuscula accumulated 10 times more Pb (13.5 mg g⁻¹) than S. subsalsa (1.32 mg g⁻¹) at pH 6 within 3 h of exposure to 20 mg L⁻¹ Pb(II) solution and 76% of the Pb could be recovered using 0.1 M EDTA. This chelator (2 μM) did not influence Pb accumulation whereas 100 μM citrate increased that of S. subsalsa 6- to 8-fold. L. majuscula filaments enmeshed in a glass wool packed in a column removed 95.8% of the Pb from a 5 mg L⁻¹ Pb solution compared to free and dead biomass which removed 64 and 33.6% Pb respectively. A 92.5% recovery of accumulated Pb from the immobilized biomass suggests that repeated absorption-desorption is possible.     

Polyphenols isolated from antiradical extracts of Mallotus metcalfianus

Six flavonoids including two new flavones, luteolin 7-O-(4″-O-(E)-coumaroyl)-β-glucopyranoside), chrysoeriol-7-O-(4″-O-(E)-coumaroyl)-β-glucopyranoside) and a mixture of two pairs of diastereoisomeric flavonolignans, (±)-hydnocarpin 7-O-(4″-O-(E)-coumaroyl)-β-glucopyranoside)/(±)-hydnocarpin-D 7-O-(4″-O-(E)-coumaroyl)-β-glucopyranoside) with a 2:1 ratio were isolated from the whole plant of Mallotus metcalfianus Croizat, in addition to 10 known compounds. Their structures were evaluated on the basis of different spectroscopic methods, including extensive 1D and 2D NMR spectroscopy. Some extracts have moderate antimicrobial properties and interesting antiradical (DPPH) activity, as well as some compounds isolated from this species. Tannins were also identified in some active extracts.     

Influence of viscous Rhodella grisea (Rhodophyceae) proteoglycan on chemically induced cough reflex

An algal extracellular biopolymer (over 8.5 × 10⁵ Da) composed of carbohydrates (52%) and protein (∼13%) has been isolated from a red alga Rhodella grisea growing in natural conditions by concentration of water medium, alcohol precipitation, dialysis and freeze-drying. This mucilagineous biopolymer contained xylose and its 3-O- and 4-O-methyl derivatives (∼63%), galactose (∼12%), glucuronic acid (11-12%), glucose (∼5%), rhamnose (∼4%), fucose (∼3-4%) and low content of others accompaning sugars. When tested on the citric acid-induced cough and reactivity of airways smooth muscle in vivo in the test system guinea pigs, this biopolymer assigned a significant cough suppressing effect. The reactivity of airways smooth muscle was not affected indicating that expectoration effect was not suppressed by biopolymer application, which is important from the pharmacological point of view.