Two Novel Ceramides with a Phytosphingolipid and a Tertiary Amide Structure from <Emphasis Type="Italic">Zephyranthes candida</Emphasis>

Two novel ceramides, Candidamide A (1) with a phytosphingolipid structure, and Candidamide B (2) with a tertiary amide structure, together with 12 known compounds (3–14) have been isolated from the bulbs of Zephyranthes candida, The structures of 1 and 2 have been elucidated to be 1,3,5,6-tetrahydroxy-2-(2′-hydroxytetracosanoyl amino)-8-(E)-octadecadiene (1) and (2S,3S,4R,8E,2′R)-2-[N-(2′-hydroxyoctadecanoyl)-N-(1′′,2′′-dihydroxyethyl)-amino]-8-hexacosene-1,3,4-triol (2) on the basis of spectroscopic evidence including IR, MS, NMR (¹H-NMR, ¹³C-NMR, DEPT, ¹H–¹H COSY, HSQC, HMBC). The known compounds were identified as (2S)-3′,7-dihydroxy-4′-methoxyflavan (3), (2S)-4′-hydroxy-7-methoxyflavan (4), (2S)-4′,7-dihydroxyflavan (5), 7-hydroxy-3′, 4′-methylenedioxyflavan (6), ambrettolide (7), β-sitostero1 (8), β-daucosterin (9), rutin (10), pancratistatin (11), lycorine (12), haemanthidine (13), and haemanthamine (14). In the antimicrobial assay, candidamide A (1) and candidamide B (2) displayed moderate activities against bacteria Staphylococcus aureus and Escherichia coli, and fungi Aspergillus niger, Candida albicans and Trichophyton rubrum.     

Novel imine from Hemsleya macrocarpa var. clavata

The new substance hemsleyin imine A (1) was isolated along with (2S,3S,4R,2′R)-2-(2′-hydroxytetracosanoylamino)-octadecan-1,3,4-triol (2), (2S,3R,4E,8E)-1-O-β-d-glucopyranosyl-3-hydroxy-2-(2′R-hydroxypalmitoylamino)-4,8-octadecadiene (3) from the rhizomes of Hemsleya macrocarpa var. clavata. Their chemical structures were established mainly by spectral analysis and chemical evidence. Compound 1 possesses the skeleton of an imine moiety, which is novel in natural products.     

A new ceramide from the basidiomycete Russula cyanoxantha

A new phytosphingosine-type ceramide (1) was isolated along with nine other compounds—5α,8α-epidioxy-(22E,24R)-ergosta-6,22-dien-3β-ol, 5α,8α-epidioxy-(24S)-ergosta-6-en-3β-ol, (24S)-ergosta-7-ene-3β,5α,6β-triol,(22E,24R)-ergosta-7, 22-dien-3β,5α,6β-triol, inosine, adenine, l-pyroglutamic acid, fumaric acid, and d-allitol from the ethanol and chloroform/methanol extract of the fruiting bodies of the basidiomycete Russula cyanoxanotha (Schaeff.) Fr. The structure of (1) was established as (2S,3S,4R,2′R)-2-(2′-hydroxytetracosanoylamino) octadecane-1,3,4-triol by means of spectroscopic and chemical methods.     

New glyceroglycolipid and ceramide from <Emphasis Type="Italic">Premna microphylla</Emphasis>

Iwo new compounds (1,2) were isolated from the ethanolic extract of the leaves of Premna microphylla, together with five known compounds. The structures of compounds 1 and 2 were elucidated as (2S,3S,4R,11E)-2-[(2R)-2-hydroxytetracosanoylamino]-11-octadecene-1,3,4-triol (1) and 1-O(9Z,12Z, 15Z-octadecatrienoyl)-3-O-[β-d-galactopyranosyl-(1→6)-O-β-d-galactopyranosyl-(1→6)-α-d-galactopyranosyl] glycerol (2) by means of spectroscopic and chemical methods.     

New Sphingolipids with a Previously Unreported 9-Methyl-C<Subscript>20</Subscript>-sphingosine Moiety from a Marine Algous Endophytic Fungus <Emphasis Type="Italic">Aspergillus niger</Emphasis> EN-13

Asperamides A (1) and B (2), a sphingolipid and their corresponding glycosphingolipid possessing a hitherto unreported 9-methyl-C₂₀-sphingosine moiety, were characterized from the culture extract of Aspergillus niger EN-13, an endophytic fungus isolated from marine brown alga Colpomenia sinuosa. The structures were elucidated by spectroscopic and chemical methods as (2S,2′R,3R,3′E,4E,8E)-N-(2′-hydroxy-3′-hexadecenoyl)-9-methyl-4,8-icosadien-1,3-diol (1) and 1-O-β-d-glucopyranosyl-(2S,2′R,3R,3′E,4E,8E)-N-(2′-hydroxy-3′-hexadecenoyl)-9-methyl-4,8-icosadien-1,3-diol (2). In the antifungal assay, asperamide A (1) displayed moderate activity against Candida albicans.     

A new glucoceramide from the watermelon begonia, <Emphasis Type="Italic">Pellionia repens</Emphasis>

A new glucoceramide named pellioniareside (1) was isolated from the aqueous ethanolic extract of whole plants of Pellionia repens, together with lupeol (2), uracil (3), (22E,20S,24R)-5α,8α-epidioxyergosta-6,22-dien-3-β-ol (4), and daucosterol (5). The structure and relative configurations of pellioniareside were identified as (2S,3S,4R,6E,8E)-1-O-β-d-glucopyranosyl-2-[(2R)-2-hydroxytetracosanoylamino]-1,3,4-octadecanetriol-6,8-diene by analysis of spectral data and by chemical evidence.     

Pecipamide,a New Sphingosine Derivative from the Cultures of <Emphasis Type="Italic">Polyporus picipes</Emphasis> (Basidiomycetes)

A new C₁₈-ceramide congener named pecipamide (1), together with the known ergosta-4,6,8(14),22-tetraen-3-one (2), was isolated from the solid fermentations of the basidiomycetous fungus Polyporus picipes. The structure of the new metabolite was established as (2′R,2S,3R)-N-2′-hydroxyheptadecanoyl-2-amino-octadecane-1,3-diol on the basis of spectroscopic data, including 1D- and 2D- nuclear magnetic resonance spectroscopy (NMR) experiments, as well as by means of mass spectrometric measurements (MS).     

New Nortriterpenoid and Ceramides From Stems and Leaves of Cultivated <Emphasis Type="Italic">Triumfetta cordifolia</Emphasis> A Rich (Tiliaceae)

To highlight the role of plants in traditional healing, the leaves and the stems of cultivated Triumfetta cordifolia were phytochemically studied yielding a new nor-ursane type (1), a new ceramide (2) and a new piperidinic ceramide derivative (3) named, respectively, 2α,19α-dihydroxy-3-oxo-23-nor-urs-12-en-28-oic acid, (2R)-2-hydroxy-N-[(2S,3S,4R,26E)-1,3,4-trihydroxy-26-triaconten-2-yl] tetradecanamide and (2R,8Z)-2-hydroxy-{(2S,3R,5R,6S)-3,5-dihydroxy-6-[(1E,5Z)-hexadeca-1,5-dienyl]-2-(β-d-glucopyranosyloxy)methyl piperidine-1-yl} tetracos-8-enamide (3). These were obtained together with lupeol (4), stigmasterol (5), 3-O-β-d-glucopyranoside of β-sitosterol (6), tormentic acid (7) from stems and heptadecanoic acid (8), β-carotene (9), oleanolic acid (10), and 24-hydroxytormentic acid (11) from leaves. The structures were determined on the basis of NMR data (¹H-, ¹³C-, 2D-NMR analyses), mass spectrometry and confirmed by chemical transformations as well as comparison of spectral data with those reported in the literature. The FRAP method was used to evaluate the antioxidant activity of fractions collected from flash chromatography and isolated compounds. Among the fractions, four reduced Fe^III-TPTZ to Fe^II-TPTZ while isolated pure compounds showed no activity.     

New glycosphingolipid containing an unusual sphingoid base from the basidiomycete Polyporus ellisii

A new 9-methyl-sphinga-4,8-dienine-containing glucocerebroside (1), together with two additional known analogs, cerebrosides B and D, was isolated from the chloroform-soluble lipid fraction of the ethanol and chloroform/methanol extract of the fruiting bodies of the basidiomycete Polyporus ellisli Berk. and characterized. The structure and relative stereochemistry of the new compound were identified as (2S,3R,4E,8E)-1-(β-d-glucopyranosyl)-3-hydroxy-2-[(R)-2′-hydroxyheptadecanoyl]amino-9-methyl-4,8-octadecadiene by means of spectroscopic (¹H, ¹³C, and two-dimensional nuclear magnetic resonance; mass spectrometry) and chemical methods.     

New cerebrosides from the basidiomycete <Emphasis Type="Italic">Cortinarius tenuipes</Emphasis>

Five cerebrosides (1–5), including three new ones named cortenuamide A (1), cortenuamide B (2), and cortenuamide C (3), were isolated from the fruiting bodies of the basid-iomycete Cortinarius tenuipes. The structures of those compounds were elucidated as (4E,8E)-N-d-2′-hydroxytetracosanoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8-sphingadienine (1), (4E,8E)-N-d-2′-hydroxytricosanoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8 sphingadienine (2), (4E, 8E)-N-d-2′-hydroxydocosanoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8-sphingadienine (3), (4E, 8E)-N-d-2′-hydroxyoctadecanoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8-sphingadienine (4), and (4E, 8E)-N-d-2′-hydroxypalmitoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8-sphingadienine (5) by spectral and chemical methods.     

Isolation and structure of glucosylceramides from the starfish Cosmasterias lurida

From the water-insoluble lipid fraction of the methylene chloride/methanol extract of the starfish Cosmasterias lurida, two new glucosylceramides together with a known glucosylceramide, ophidiacerebroside E, were isolated by chromatographic procedures and characterized by spectroscopic (¹H and ¹³C nuclear magnetic resonance, mass spectrometry) methods. The new compounds were identified as (2S, 3R, 4E, 8E, 10E)-1-(β-d-glucopyranosyloxy)-3-hydroxy-2-[(R)-2-hydroxyheptadecanoyl)amino]-9-methyl-4,8,10-octadecatriene (3) and (2S,3R,4E,8E,10E)-1-(β-d-glucopyranosyloxy)-3-hydroxy-2-[(R)-2-hydroxyoctadecanoyl)amino]-9-methyl-4,8,10-octadecatriene (4).     

Two novel glucosylceramides from gonads and body walls of the Patagonian starfish Allostichaster inaequalis

From the water-insoluble lipid fraction of the chloroform/methanol/water extract of the gonads and body walls of the Patagonian starfish Allostichaster inaequalis, two new glucosylceramides (4 and 7) were isolated together with the known phalluside-1 (1) and two glucosylceramides (2 and 3) previously isolated from the starfish Cosmasterias lurida. The new compounds were characterized as (2S,3R,4E,8E,10E)-1-(β-d-glucopyranosyloxy)-3-hydroxy-2-[(R)-2-hydroxy-15-tetracosenoyl] amino-4,8,10-octadecatriene (4) and (2S,3R,4E,15Z)-1-(β-d-glucopyranosyloxy)-3-hydroxy-2-[(R)-2-hydroxyhexadecanoyl] amino-4,15-docosadiene (7) by means of spectroscopic and chemical methods.     

Antibacterial and xanthine oxidase inhibitory cerebrosides from <Emphasis Type="Italic">Fusarium</Emphasis> sp. IFB-121, and endophytic fungus in <Emphasis Type="Italic">Quercus variabilis</Emphasis>

Two antibacterial and xanthine oxidase inhibitory cerebrosides, one of which is chemically new, were characterized from the chloroform-methanol (1∶1) extract of Fusarium sp. IFB-121, an endophytic fungus in Quercus variabilis. By means of chemical and spectral methods [IR, electrospray ionization MS (ESI-MS), tandem ESI-MS, ¹H and ¹³C NMR, distortionless enhancement by polarization transfer, COSY, heteronuclear multiple-quantum coherence, heteronuclear multiple-bond correlation, and 2-D nuclear Overhauser effect correlation spectroscopy], the structure of the new metabolite named fusaruside was established as (2S,2′R,3R,3′E,4E,8E,10E)-1-O-β-d-glucopyranosyl-2-N-(2′-hydroxy-3′-octadecenoyl)-3-hydroxy-9-methyl-4,8,10-sphingatrienine, and the structure of the other was identified as (2S,2′R,3R,3′E,4E,8E)-1-O-β-d-glucopyranosyl-2-N-(2′-hydroxy-3′-octadecenoyl)-3-hydroxy-9-methyl-4,8-sphingadienine. Both new and known cerebrosides, although inactive to Trichophyton rubrum and Candida albicans, showed strong antibacterial activities against Bacillus subtilis, Escherichia coli, and Pseudomonas fluorescens, with their minimum inhibitory concentrations being 3.9, 3.9, and 1.9 μg/mL, and 7.8, 3.9, and 7.8 μg/mL, respectively. Furthermore, both metabolites were inhibitory to xanthine oxidase, with the IC₅₀ value of fusaruside being 43.8±3.6 μM and the known cerebroside being 55.5±1.8 μM.     

Novel oxylipins from the temperate red alga polyneura latissima: Evidence for an arachidonate 9(S)-lipoxygenase

The oxylipin chemistry of the temperate red alga Polyneura latissima has been investigated. The structures of three novel oxylipins, 8-[1′(Z),3′(Z),6′(Z)-dodecatriene-1′-oxyl-5(Z),7(E)-octadienoic acid, 7(S ^*)-hydroxy-8(S ^*),9(S ^*)-epoxy-5(Z), 11(Z),14(Z)-eicosatrienoic acid, 7(R ^*)-hydroxy-8(S ^*), 9(S ^*)-epoxy-5(Z), 11(Z),14(Z)-eicosatrienoic acid, together with two known eicosanoids, 9(S)-hydroxy-5(Z), 7(E), 11(Z), 14(Z)-eicosatetraenoic acid, and 9, 15-dihydroxy-5(Z),7(E),11(Z),13(E)-eicosatetraenoic acid, were elucidated by spectroscopic methods and chemical degradation. The oxygenation pattern of these oxylipins suggests that P. latissima metabolizes polyunsaturated fatty acids via a 9(S)-lipoxygenase.     

Divinyl ethers and hydroxy fatty acids from three species ofLaminaria (brown algae)

Three species of brown algae,Laminaria sinclairii, L. saccharina andL. setchellii, have been investigated for the presence of oxylipins. From one,L. sinclairii, three new divinyl ether fatty acids have been characterized as methyl ester derivatives (methyl 12-[1′ (Z),3′(Z)-hexadienyloxy]-6(Z), 9(Z), 11(E)-dodecatrienoate, methyl 12-[1′ (Z), 3′ (Z)-hexadienyloxy]-9(Z), 11(E)-dodecatrienoate, and methyl 14-[1′ (Z),3′ (Z)-hexadienyloxy]-9(Z),11(E)-dodecadienoate, and methyl 14-[1′ (Z),3′(Z)-hexadienyloxy]-5(Z),8(Z),11(Z),13(E)-tetradecatetraenoate) by a variety of spectroscopic methods. In addition, one new [13(S)-hydroxy-6(Z),9(Z),11(E),15(Z)-octadecatetraenoic acid] and four known monohydroxy polyunsaturated fatty acids have been isolated from all three species as their methyl ester derivatives. The occurrence of these compounds in brown algae strongly suggests that these organisms possess an active lipoxygenase(s) with ω6 specificity. A preliminary summary of this work was presented at the XIVth International Seaweed Symposium, Brest, France, August 1992 (10).     

Optical properties of alkali and alkaline-earth lead borate glasses doped with Nd<Superscript>3+</Superscript> Ions

Spectroscopic and physical properties of Nd³⁺-doped alkali lead borate glasses of type 20R ₂O · 30PbO · 49.5B₂O₃ · 0.5Nd₂O₃ (R = Li and K) and alkaline-earth lead borate glasses 20RO · 30PbO · 49.5B₂O₃ · 0.5Nd2O3 (R = Ca, Ba, and Pb) have been investigated. Optical absorption spectra have been used to determine the Slater-Condon (F₂, F₄, and F₆), spin orbit ξ_4f, and Racah parameters (E₁, E₂, and E₃). The oscillator strengths and the intensity parameters Ω₂, Ω₄, and Ω₆ have been determined by the Judd-Ofelt theory, which, in turn, provide the radiative transition probability (A), total transition probability (A _T ), radiative lifetime (τ _R ), and branching ratio (β _R , %) for the fluorescent levels. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Ω₄/Ω₆), the value of which is in the range 0.2–1.5, typical of Nd³⁺ in different laser hosts. A red shift of the peak wavelength is observed upon addition of alkali or alkaline-earth oxides to the lead borate glass. A higher value of the W₂ parameter for potassium-doped glass indicates a higher covalency for this glass matrix. The relative intensity of the peaks ⁴I_9/2 → ⁴F_7/2, ⁴S_3/2 has also been studied. The text was submitted by the authors in English.     

Fatty acid hydroperoxide isomerase inSaprolegnia parasitica: Structural studies of epoxy alcohols formed from isomeric hydroperoxyoctadecadienoates

The major part (80%) of the fatty acid hydroperoxide isomerase activity present in homogenates of the fungus,Saprolegnia parasitica, was localized in the particle fraction sedimenting at 105,000×g. 13(S)-Hydroperoxy-9(Z),11(E)-octadecadienoic acid and 9(S)-hydroperoxy-10(E),12(Z)-octadecadienoic acid were both good substrates for the particle-bound hydroperoxide isomerase. The products formed from the 13(S)-hydroperoxide were identified as an α,β- and a γ,δ-epoxy alcohol, i.e., 11(R),12(R)-epoxy-13(S)-hydroxy-9(Z)-octadecenoic acid and 9(S),10(R)-epoxy-13(S)-hydroxy-11(E)-octadecenoic acid, respectively. The 9(S)-hydroperoxide was converted in an analogous way into an α,β-epoxy alcohol, 10(R),11(R)-epoxy-9(S)-hydroxy-12(Z)-octadecenoic acid and a γ,δ-epoxy alcohol, 12(R),13(S)-epoxy-9(S)-hydroxy-10(E)-octadecenoic acid. 9(R,S)-Hydroperoxy-10(E),12(E)-octadecadienoic acid and 13(R,S)-hydroperoxy-9(E),11(E)-octadecadienoic acid were poor substrates for theS. parasitica hydroperoxide isomerase. Experiments with 13(R,S)-hydroperoxy-9(Z),11(E)-octadecadienoic acid showed that the 13(R)-hydroperoxy enantiomer was slowly isomerized by the enzyme. The major product was identified as α,β-epoxy alcohol 11(R),12(R)-epoxy-13(R)-hydroxy-9(Z)-octadecenoic acid.     

A pathway for biosynthesis of divinyl ether fatty acids in green leaves

[1-¹⁴C]α-Linolenic acid was incubated with a particulate fraction of homogenate of leaves of the meadow buttercup (Ranunculus acris L.). The main product was a divinyl ether fatty acid, which was identified as 12-[1′(Z),3′(Z)-hexadienyloxy]-9(Z), 11(E)-dodecadienoic acid. Addition of glutathione peroxidase and reduced glutathione to incubations of α-linolenic acid almost completely suppressed formation of the divinyl ether acid and resulted in the appearance of 13(S)-hydroxy-9(Z), 11(E), 15(Z)-octadecatrienoic acid as the main product. This result, together with the finding that 13(S)-hydroperoxy-9(Z), 11(E), 15(Z)-octadecatrienoic acid served as an efficient precursor of the divinyl ether fatty acid, indicated that divinyl ether biosynthesis in leaves of R. acris occurred by a two-step pathway involving an ω6-lipoxygenase and a divinyl ether synthase. Incubations of isomeric hydroperoxides derived from α-linolenic and linoleic acids with the enzyme preparation from R. acris showed that 13(S)-hydroperoxy-9(Z), 11(E)-octadecadienoic acid was transformed into the divinyl ether 12-[1′(Z)-hexenyloxy]-9(Z), 11(E)-dodecadienoic acid. In contrast, neither the 9(S)-hydroperoxides of linoleic or α-linolenic acids nor the 13(R)-hydroperoxide of α-linolenic acid served as precursors of divinyl ethers.     

Novel ceramides and a new glucoceramide from the roots of <Emphasis Type="Italic">Incarvillea arguta</Emphasis>

Novel ceramides, rel-(3S,4S,5S)-3-[(2R)-2-hydroxycosanoyl-hexacosanoylamino]-4-hydroxy-5-[(4Z)-tetradecane-4-ene]-2,3,4,5-tetrahydrofuran (1a-g), and a new glucoceramide, 1-O-β-d-glucopyranosyl-(2S,3S,4R,8E)-2-[(2R)-2-hydroxytetracosanoylamino]-1,3,4-octodecanetriol-8-ene (2) were isolated from the aqueous ethanolic extract of the roots of Incarvillea arguta, together with eight known compounds: β-sitosterol (3), oleanolic acid (4), ursolic acid (5), piperin (6), maslinic acid (7), β-sitosterol 6′-O-acyl-β-d-glucopyranoside (8), 8-epideoxyloganic acid (9), and plantarenaloside (10). Their structures were elucidated on the basis of spectral data including IR, MS, NMR [¹H NMR, ¹³C NMR (distortionless enhancement by polarization transfer), ¹H−¹H COSY, heteronuclear multiplequantum coherence, and heteronuclear multiple-bond coherence correlations]. The relative configurations were established by nuclear Overhauser effect spectroscopy experiments and by comparison of the NMR spectral data and coupling constants with those already reported in the literature.     

Studies toward the synthesis of the shark repellent pavoninin-5

Sharks are the most dangerous predators of people in the sea, resulting in people being mauled and killed each year. A shark repellent could help to diminish this danger. The aglycone of the shark repellent pavoninin-5, (25R)-cholest-5-en-3β,15α,26-triol (5a), was synthesized from diosgenin (9). Removing mercury from the Clemmensen reduction of 9 gave a higher yield of (25R)-cholest-5-en-3β,16β,26-triol, 10a, and was also more environmentally friendly. Attempted methods for the transposition of the C-16β hydroxyl to the 15α position are described. A successful method for this transposition via the 15α-hydroxy-16-ketone, 8a, using the Barton deoxygenation reaction on the 16-alcohol 14b, is reported.