Structural diversity of d-galacto-d-mannan components isolated from lichens having ascomycetous mycosymbionts

d-Galacto-d-mannan fractions were isolated from six common Canadian lichens having ascomycetous mycosymbionts, namely Parmelia sulcata, Stereocaulon paschale, Peltigera aphthosa, Letharia vulpina, Actinogyra muehlenbergii, and an Usnea sp. Their chemical structures were compared with each other and those of six species previously investigated; only Parmelia sulcata and Cetraria islandica (Iceland moss) contained galactomannans of closely related structures. The structural diversity depends on substituents on the (1→6)-linked α-d-mannopyranosyl main-chains. The side-chains occur as monosubstituents at O-2 or O-4 or as disubstituents at O-2,4. Frequently, the main-chain units are unsubstituted. Thus far, eight types of substitution have been recognized (1–8) in which β-d-Galp is linked (1→4), α-d-Galp and α-d-Manp (1→2), and β-d-Galf (1→4).     

THE RESPONSE OF DIFFERENTCLADONIASPECIES AFTER TREATMENT WITH FERTILIZER OF LIME IN HEATHLAND

The effect of deposition of different fertilizers and of lime on lichens was investigated under field conditions. Three terricolous lichens were tested:Cladonia floerkeanaC. furcataandC. portentosa. The lichens were exposed to three types of powdered fertilizer (NPK-, N-, P-fertilizer) and lime. The applied nutrients were recorded in lichen thalli and soil. the influence on lichen growth rate and vegetation cover was estimated over 2 years. The response was a clear change in vegetation cover with an exceptional stimulating effect of NPK on the mossPolytrichum formosum. A lethal effect was observed onCladonia floerkeanafollowing exposure to lime. NPK and P had the most significant stimulatory effect onC. furcata. Only NPK promoted the growth ofC. portentosaand P, N or Ca had a negative effect.     

Depolymerization of legume seed galactomannan by Celloviridin G20x

The depolymerization of legume galactomannans by the commercial preparation Celloviridin G20x was studied with the aim of obtaining macromolecular fragments of a constant composition. Four galactomannans, representative of the entire range of monomer ratios characteristic of this class of phytopolysaccharides, were hydrolyzed. The galactomannans were isolated from oriental goat’s rue (Galega orientalis Lam., Man: Gal 1.1), guar (Cyamopsis tetragonoloba L., Man: Gal 1.6), honeylocust (Gleditsia triacanthos f. inermis L., Man: Gal 2.4), and sophora (Styphnolobium japonicum (L.) Schott., Man: Gal 5.1). Fragments with a monomer ratio close to that in the original polysaccharides were obtained with a high yield (75–80%). The degree of substitution of the 1,4-β-D-mannopyranose chain at position C-6 with α-galactose residues influenced the molecular weight of the final reaction product.     

Composition and Structure of Galactomannan from the Seed of Gleditsia ferox Desf.

Galactomannan, a heteropolysaccharide with a molecular weight of 1660 kDa, was isolated from the seed of Gleditsia ferox Desf., introduced in Russia, with a yield of 18.9%. Its aqueous solutions were optically active ([]_D = +30.5°) and highly viscous ([] = 1430 ml/g). An analysis of the heteropolysaccharide using chemical, enzymatic, and chromatographic procedures showed that it consists of D-mannopyranose and D-galactopyranose residues (molar ratio, 2.54 : 1). The main chain of this galactomannan consists of 1,4--D-mannopyranose residues, 39.2% of which are substituted at C6 with single residues of -D-galactopyranose. The probability of occurrence of mannobiose units differentially substituted with galactose was determined by ¹³C-NMR data and equaled, respectively, 0.37, 0.47, and 0.16 for non-substituted Man–Man units, monosubstituted Gal(Man–Man) and (Man–Man)Gal units taken together, and for the disubstituted Gal(Man–Man)Gal units.     

Oligosaccharides from “standardized intermediates”. Synthesis of a branched tetrasaccharide glycoside isomeric with the blood-group B,type 2 determinant

Building-block derivatives of the component monosaccharides were used to construct the tetrasaccharide glycoside 15, in which an α- d-Galp-(1→4)- d-Gal linkage replaces the α-(1→3) linkage of the human blood-group B, type 2, determinant structure. The initial coupling of 2-O-benzoyl-3,6-di-O-benzyl-4-O-(tetrahydropyran-2-yl)-α- d-galactopyranosyl chloride to allyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-β- d-glucopyranoside was followed by selective deprotection of the disaccharide product, either at O-4′ (to give 8) or O-2′ (to give 3). The conversion of 8 into 15 involved successive coupling with tetra-O-benzyl-α- d-galactopyranosyl bromide ( 8 → 11), O-debenzoylation at O-2′ ( 11 → 12), coupling with tri-O-benzyl-α- l-fucopyranosyl bromide ( 12 → 14), and O-debenzylation by hydrogenolysis ( 14 → 15). Alternatively, 3 was α- l-fucosylated to give 6, and 6 was selectively deprotected at O-4′ to give 7. However, attempts to α- d-galactosylate 7 were unsuccessful. The unsubstituted forms of the intermediate disaccharide ( 8) and trisaccharide ( 12) glycosides were obtained by appropriate deblocking procedures.     

A new subspecies and new combinations in Comarostaphylis (Ericaceae)

Comarostaphylis spinulosa subsp.glandulifera is described from the mountains of Oaxaca and Puebla, Mexico. Four new combinations inComarostaphylis are also made:C. arbutoides subsp.costaricensis, C. discolor subsp.rupestris, C. polifolia subsp.minor, andC. spinulosa.Arctostaphylos glabrata, A. rupestris, andA. spinulosa are lectotypified and the status ofC. polifolia is discussed.     

C-4′-Branched-chain sugar nucleosides: synthesis of isomers of psicofuranine

Photoamidation of 3-O-acetyl-1,2:5,6-di-O-isopropylidene-α-d-erythro-hex-3-enofuranose (1) afforded 3-O-acetyl-4-C-carbamoyl-1,2:5,6-di-O-isopropylidene-α-d-gulofuranose (2) and 3-O-acetyl-3-C-carbamoyl-1,2:5,6-di-O-isopropylidene-d-α-allofuranose (3) in 65 and 26% yields, respectively (based on consumed1). Treatment of2 with 5% hydrochloric acid in methanol yielded the spiro lactone5, which was deacetylated to yield7. Reduction of5 with sodium borohydride afforded 4-C-(hydroxymethyl)-1,2-O-isopropylidene-α-d-gulofuranose (9) in 79% yield. Oxidation of9 with sodium metaperiodate afforded a dialdose that was reduced with sodium borohydride to give 4-C-(hydroxymethyl)-1,2-O-isopropylidene-α-d-erythro-pentofuranose (11) in 88% yield. Treatment of the acetate12, derived from11, with trifluoroacetic acid, followed by acetylation, afforded the branched-chain sugar acetate14. Condensation of the glycosyl halide derived from14 withN⁶-benzoyl-N⁶, 9-bis-(trimethylsilyl)adenine yielded an equimolar anomeric mixture of protected nucleosides15 and16 in 40% yield. Treatment of the latter compounds with sodium methoxide in methanol afforded 9-[4-C-(hydroxymethyl)-β-d-erythro-pentofuranosyl]-adenine (17) and the α-d anomer18. The structure of3 was determined by correlation with the known 5,3′-hemiacetal of 3-C-(hydroxymethyl)-1,2-O-isopropylidene-α,α′-d-ribo-pentodialdose (25).     

A novel synthesis of 2-deoxy-α-glycosides

The key step of the synthesis involves the reaction of glycals [3,4,6-tri-O-acetyl-d-glucal (1), the new glycal derivative 4-O-acetyl-1,5-anhydro-2,6-dideoxy-3-C-methyl-3-O-methyl-l-ribo-hex-l-enitol (2), and 3-acetamido-4,6,-di-O-acetyl-1,5-anhydro-2,3-dideoxy-d-arabino-hex-l-enitol (3)] with 1.5 molar equivalents of several alcohols in the presence ofN-bromosuccinimide in acetonitrile to give mainly the corresponding 2-bromo-2-deoxy-α-glycopyranosides (4-21). The glycopyranosides (4-8 and16-21) from1 and3 have the α-d-manno configuration and those (10-15) from2 have the α-l-altro configuration. The yields are high from1, virtually quantitative from2, and moderate from3. Debromination of the 2-bromo-2-deoxy compounds with tributylstannane and a radical initiator gives the corresponding 2-deoxy-α-glycopyranosides (22-38) in quantitative yields. In particular, the branched-chain glycal2 reacts with alcohols to give exclusively the corresponding α-glycopyranosides (27-32) of cladinose in strikingly high overall yields. The stereoselectivity and regiospecificity of the bromination reaction are described. 1,3-Dibromo-5,5-dimethylhydantoin andN-bromoacetamide are also found to be useful for the reaction.     

Two new species of Costus (Costaceae) from Costa Rica

As a result of a review of the Costaceae for theManual de las Plantas de Costa Rica, two new species ofCostus (C. ricus andC. osae) are here described and illustrated. The assignment of the new species ofCostus subgen.Costus is discussed.     

New genera and species of ericaceae (Vaccinieae) from Costa Rica and Panama

Two new monotypic genera,Didonica andUtleya, are described, withD. pendula from Panama andU. costaricensis from Costa Rica.Disterigma trimera (Panama),D. utleyorum (Costa Rica, Panama, Colombia, and Ecuador),Lateropora santafeensis (Panama),Lysiclesia panamensis (Panama),Macleania talamancensis (Costa Rica),Themistoclesia costaricensis (Costa Rica) andT. horquetensis (Panama),Vaccinium costaricense andV. orosiense (both from Costa Rica) and V.jefense (Panama) are all described as new. New combinations are provided for the PanamanianVaccinium floccosum (=Symphysia floccosa) and the West IndianVaccinium racemosum (=Symphysia racemosa). Keys are provided for the Central American species ofDisterigma andThemistoclesia, the species ofLateropora andLysiclesia, and the Costa Rican and Panamanian species ofVaccinium. Six new species are illustrated.     

New species of Cuphea section Melvilla (Lythraceae) and an annotated key to the section

Three novelties inCuphea sectionMelvilla subsect.Pachycalyx are described from Brazil;C. andersonii andC. cylindracea from Pará, andC. sabulosa from Amazonas. An annotated key to the 47 species ofCuphea sectionMelvilla is provided, the first since the 1903 monograph of the family, which then included 27 species in the section. The key identifies those species ofCuphea with thick, dorsally convex, red- or yellow-tubed flowers distributed from Mexico to Argentina.     

Notes on calycophyllous Rubiaceae. Part I. Morphological comparisons of the genera Chimarrhis,Bathysa, and Calycophyllum,with new combinations and a new species,Chimarrhis gentryana

A comparison of some genera of the Condaminecae (Rubiaceae) with a few taxa of closely related tribes (Rondeletieae, Calycophylleae, and Cinchoneae) revealed that some species ofChimarrhis (Condamineeae s. 1.),Bathysa (Rondeletieae), andCalycophyllum (Calycophylleae) are often misassigned to genera. The taxonomic significance of calycophylls is discussed; the generic boundaries ofChimarrhis, Bathysa, andCalycophyllum are reevaluated; and their similarities and differences are discussed. As a result, a new calycophyllous species ofChimarrhis from the Amazon,C. gentryana, is described, two of its species are transferred toBathysa (B. Bathysoides, B. perijaënsis), and one species ofBathysa (B. difformis) is reduced to synonymy underChimarrhis (C. turbinata).     

Stereospecificity of the O→N acyl migration in 2,3,4,6-tetra-O-benzoyl-β-D-mannopyranosylamine

By heating tetra-O-benzoyl-α-D-mannopyranosyl bromide with sodium azide, 2,3,4,6-tetra-O-benzoyl-β-d-mannopyranosyl azide (3) was obtained. Catalytic hydrogenation of 3 produced 2,3,4,6-tetra-O-benzoyl-β-d-mannopyranosylamine (4). Ammonolysis of 4 afforded N-benzoyl-β-d-mannopyranosylamine (7) in good yield (60%) and a mixture of d-mannose and d-mannopyranosylamine (34%). No other compound was characterized. This result shows that, in O-acylated glycosylamines, O→N acyl migration is stereospecific and takes place when there is a cis relation between the O-acyl group at O-2 and the amino group at C-1.     

New taxa of Consolea Lemaire (Cactaceae: Opuntioideae) from Cuba

The ranges ofConsolea nashii andC. moniliformis were found to extend from the Bahamas and Hispaniola, respectively, into Cuba. Two new subspecies are now recognized on the basis of morphological and geographical discontinuities of populations:Consolea nashii subsp.gibarensis from the coastal thickets between Manatí and Maisí, northeastern Cuba, andC. moniliformis subsp.guantanamana from the cacti thorn-woodlands and thickets of Guantánamo and Santiago de Cuba Provinces, on the southern coast and adjacent dry plains of eastern Cuba. A key to the Cuban species ofConsolea is provided.     

Synthesis of novel indenoquinoxaline derivatives as potent α-glucosidase inhibitors

A series of new N-(11H-Indeno[1,2-b]quinoxalin-11-ylidene)benzohydrazide derivatives (3a–3p) were synthesized and evaluated for their α-glucosidase inhibitory activity. The synthesized compounds 3d, 3f, 3g, 3k, 3n, 3p and 4 showed significant α-glucosidase inhibitory activity as compared to acrabose, a standard drug used to treat type II diabetes. Structures of the synthesized compounds were determined by using FT-IR, ¹H NMR, ¹³C NMR, mass spectrometry and elemental analysis techniques.     

Castilleja (Scrophulariaceae) of Costa Rica and Panama

The mountains of Costa Rica and western Panama constitute a natural floristic region that is inhabited by six species ofCastilleja.Castilleja talamancensis, C. lentii andC. tayloriorum are described as new. The remaining three areC. arvensis,C. irasuensis andC. quirosii. All butC. arvensis are endemic to the area. The six species are keyed, described, illustrated, mapped and documented with literature and specimen citations.     

Two new species and new records for Pteris (Pteridaceae) from Colombia

A systematic review of the Colombian species of the tribe Pterideae (Pteridaceae) resulted in the discovery of two new species ofPteris:P. muricatopedata andP. albertiae, both in the Deflexa group. Two species are reported for the first time from Colombia:P. bakeri C. Chr. andP. lechleri Mett.     

Four new iridoid glucoside p-coumaroyl esters from Ajuga decumbens

From the methanolic extract of the dried whole plant ofAjuga decumbens, four new iridoid glucosidecis- andtrans-p-coumaroyl esters, decumbeside A (1), B (2), C (7) and D (8) were isolated together with the known reptoside (6) and 8-acetylharpagide (9). The structures of the new compounds have been elucidated on the basis of spectroscopic and chemical evidence.