Showing papers in "Journal of Natural Products in 1996"
1,245 citations
TL;DR: It was revealed that Ca-SP selectively inhibited the penetration of virus into host cells, and retention of molecular conformation by chelation of calcium ion with sulfate groups was suggested to be indispensable to its antiviral effect.
Abstract: Bioactivity-directed fractionation of a hot H2O extract from a blue-green alga Spirulina platensis led to the isolation of a novel sulfated polysaccharide named calcium spirulan (Ca-SP) as an antiviral principle. This polysaccharide was composed of rhamnose, ribose, mannose, fructose, galactose, xylose, glucose, glucuronic acid, galacturonic acid, sulfate, and calcium. Ca-SP was found to inhibit the replication of several enveloped viruses, including Herpes simplex virus type 1, human cytomegalovirus, measles virus, mumps virus, influenza A virus, and HIV-1. It was revealed that Ca-SP selectively inhibited the penetration of virus into host cells. Retention of molecular conformation by chelation of calcium ion with sulfate groups was suggested to be indispensable to its antiviral effect.
370 citations
TL;DR: A crude MeOH extract of Syzygium aromaticum (clove) exhibited preferential growth-inhibitory activity against Gram-negative anaerobic periodontal oral pathogens, including Porphyromonas gingivalis and Prevotella intermedia.
Abstract: A crude MeOH extract of Syzygium aromaticum (clove) exhibited preferential growth-inhibitory activity against Gram-negative anaerobic periodontal oral pathogens, including Porphyromonas gingivalis and Prevotella intermedia. By means of bioassay-directed chromatographic fractionation, eight active compounds were isolated from this extract and were identified as 5,7-dihydroxy-2-methylchromone 8-C-beta-D-glucopyranoside, biflorin, kaempferol, rhamnocitrin, myricetin, gallic acid, ellagic acid, and oleanolic acid, based on spectroscopic evidence. The antibacterial activity of these pure compounds was determined against Streptococcus mutans, Actinomyces viscosus, P. gingivalis, and P. intermedia. The flavones, kaempferol and myricetin, demonstrated potent growth-inhibitory activity against the periodontal pathogens P. gingivalis and P. intermedia.
361 citations
TL;DR: In an ongoing survey of the bioactive potential of microorganisms associated with marine invertebrates, the culture media of a sponge-associated bacterial strain of Pseudomonas aeruginosa was found to contain metabolites which inhibit the growth of several Gram-positive microorganisms.
Abstract: In an ongoing survey of the bioactive potential of microorganisms associated with marine invertebrates, the culture media of a sponge-associated bacterial strain of Pseudomonas aeruginosa was found to contain metabolites which inhibit the growth of several Gram-positive microorganisms. A series of diketopiperazines (1-6) including a new natural product (6) and two known phenazine alkaloid antibiotics (7 and 8) were isolated from the culture broth of this bacterium.
268 citations
TL;DR: The methanol extract from the whole plant of Geum japonicum was found to inhibit the human immunodeficiency virus (HIV-1) protease through bioassay-directed fractionation of the extract, and a new triterpene acid showed potent inhibitory activity against HIV-1 protease.
Abstract: The methanol extract from the whole plant of Geum japonicum was found to inhibit the human immunodeficiency virus (HIV-1) protease. Through bioassay-directed fractionation of the extract, a new triterpene acid along with five known triterpene acids, ursolic acid, epipomolic acid, maslinic acid, euscaphic acid, and tormentic acid, were isolated. The structure of the new compound was determined by spectral means including 1H-1H COSY, HMQC, HMBC, and NOE experiments to be 2 alpha, 19 alpha-dihydroxy-3-oxo-12-ursen-28-oic acid (1). Of these compounds, 1, ursolic acid, and maslinic acid showed potent inhibitory activity against HIV-1 protease.
219 citations
TL;DR: A new antiinflammatory agent identified as 8-[C-beta-D-[2-O-(E)-cinnamoyl]glucopyranosyl]-2- [(R)-2-hydroxypropyl]-7-methoxy-5-methylchromone (1) has been isolated from Aloe barbadensis Miller.
Abstract: A new antiinflammatory agent identified as 8-[C-β-d-[2-O-(E)-cinnamoyl]glucopyranosyl]-2-[(R)-2-hydroxypropyl]-7-methoxy-5-methylchromone (1) has been isolated from Aloe barbadensis Miller. At a dose of 200 μg/mouse ear, 1 exhibited topical antiinflammatory activity equivlaent to 200 μg/ear of hydrocortisone. There was no reduction in thymus weight caused by treatment with 1 for any of the doses tested, while 200 μg/ear of hydrocortisone resulted in a 50% decrease in thymus weight.
192 citations
TL;DR: The lipid extract from a Curaçao collection of the marine cyanobacterium Lyngbya majuscula was toxic to the mollusc Biomphalaria glabrata and yielded a novel lipopeptide, barbamide, as the active compound.
Abstract: The lipid extract from a Curacao collection of the marine cyanobacterium Lyngbya majuscula was toxic to the mollusc Biomphalaria glabrata. Subsequent bioassay-guided fractionation of this extract yielded a novel lipopeptide, barbamide, as the active compound (LC100 = 10 micrograms/mL). The structure of barbamide was determined by spectroscopic methods and was found to contain several unique structural features, including a trichloromethyl group and the methyl enol ether of a beta-keto amide.
158 citations
TL;DR: Drying of the plant material had no effect on the qualitative composition of the oil and did not affect the ability of individuals familiar with marijuana smell to recognize the odor.
Abstract: The composition of the steam-distilled volatile oil of fresh and air-dried, indoor-grown marijuana was studied by GC/FID and GC/MS. In all, 68 components were detected of which 57 were fully identified. Drying of the plant material had no effect on the qualitative composition of the oil and did not affect the ability of individuals familiar with marijuana smell to recognize the odor.
152 citations
TL;DR: The majority of isolates demonstrate significant and selective in vitro antimalarial activity and a brief description of their possible structure-activity relationships is provided.
Abstract: In this short review, an approach to the isolation of potential antimalarial agents and lead compounds is outlined. A discussion of organism collection, followed by a description of biological testing and isolation methodologies, is also given. For two organisms, details of their secondary metabolite chemistry are reported. From one of these, Laurencia papillosa, the two aromatic compounds p-hydroxybenzaldehyde (1) and p-methoxybenzyl alcohol (2) were isolated. From the other, the tropical marine sponge Cymbastela hooperi, 15 diterpenes (3-17), which contain isonitrile, isothiocyanate, and isocyanate functionalities, are reported. Together with the diterpenes, three sesquiterpene hydrocarbons, 18-20, and the thiol, 21, were obtained. All structures were established by spectroscopic methods, particularly 1H-1H and 1H-13C shift-correlated 2D NMR spectroscopy and accurate mass measurement (HREIMS). The majority of isolates demonstrate significant and selective in vitro antimalarial activity. For compounds 4-17 a brief description of their possible structure-activity relationships is provided.
152 citations
TL;DR: Bioactivity-directed fractionation of the seeds of Annona muricata L. (Annonaceae) resulted in the isolation of five new compounds, three of which are among the first cis mono-tetrahydrofuran ring acetogenins to be reported.
Abstract: Bioactivity-directed fractionation of the seeds of Annona muricata L. (Annonaceae) resulted in the isolation of five new compounds: cis-annonacin (1), cis-annonacin-10-one (2), cis-goniothalamicin (3), arianacin (4), and javoricin (5). Three of these (1-3) are among the first cis mono-tetrahydrofuran ring acetogenins to be reported. NMR analyses of published model synthetic compounds, prepared cyclized formal acetals, and prepared Mosher ester derivatives permitted the determinations of absolute stereochemistries. Bioassays of the pure compounds, in the brine shrimp test, for the inhibition of crown gall tumors, and in a panel of human solid tumor cell lines for cytotoxicity, evaluated relative potencies. Compound 1 was selectively cytotoxic to colon adenocarcinoma cells (HT-29) in which it was 10,000 times the potency of adriamycin.
147 citations
TL;DR: Nigranoic acid showed activity in several anti-HIV reverse transcriptase and polymerase assays and its structure elucidation and unambiguous NMR spectral assignment were achieved by the combination of 1D- and 2D-NMR techniques with the aid of computer modeling.
Abstract: An A ring-secocycloartene triterpenoid, nigranoic acid (3,4-secocycloarta-4(28),24-(Z)-diene-3,-26-dioic acid, (1) was isolated from the stems of Schisandra sphaerandra, a Chinese traditional medicinal plant. Its structure elucidation and unambiguous NMR spectral assignment were achieved by the combination of 1D- and 2D-NMR techniques with the aid of computer modeling. Nigranoic acid showed activity in several anti-HIV reverse transcriptase and polymerase assays.
TL;DR: The crude organic extract of Dendropanax arboreus was selected as a candidate for bioassayguided fractionation on the basis of its relatively selective cytotoxicity to a subset of cell lines within the National Cancer Institute's disease-oriented in vitro tumor-screening panel.
Abstract: The crude organic extract of Dendropanax arboreus was selected as a candidate for bioassay-guided fractionation on the basis of its relatively selective cytotoxicity to a subset of cell lines within the National Cancer Institute's disease-oriented in vitro tumor-screening panel. The major compound responsible for the in vitro cytotoxicity was falcarinol (1). Several other known compounds were isolated and found to be cytotoxic, including dehydrofalcarinol (2), a diynene (3), falcarindiol (4), and dehydrofalcarindiol (5). In addition, two novel polyacetylenes, dendroarboreols A (6) and B (7), were isolated and characterized by standard and inverse-detected NMR methods. Compounds were selected from this series for absolute stereochemical determination using the modified Mosher method and preliminary in vivo evaluation using a LOX melanoma mouse xenograft model.
TL;DR: A novel lignin isolated from kenaf bast fibers had a high syringyl:guaiacyl ratio, was highly etherified, and was high in β-ether units with predominantly erythro stereochemistry as mentioned in this paper.
Abstract: A novel (possibly unique) lignin isolated from kenaf bast fibers had a high syringyl:guaiacyl ratio, was highly etherified, and was high in β-ether units with predominantly erythro stereochemistry. Moreover, it was extensively side-chain acetylated (primarily at γ), implicating 4-hydroxycinnamyl acetates as monomers in its biosynthesis.
TL;DR: Bioassay-directed fractionation of the CH2Cl2-MeOH extract of Euodia roxburghiana resulted in the isolation of two known quinoline alkaloids, buchapine and 2, and three new furoquinoline alkAloids, roxiamines A, B, and C (3-5).
Abstract: Bioassay-directed fractionation of the CH2Cl2-MeOH extract of Euodia roxburghiana resulted in the isolation of two known quinoline alkaloids, buchapine (1) and 2, and three new furoquinoline alkaloids, roxiamines A, B, and C (3-5). Compounds 1 and 2 protected CEM-SS cells from the cytopathic effects of HIV-1 in vitro (EC50 0.94 and 1.64 microM, respectively), but 3-5 were inactive against HIV-1.
TL;DR: Among these 14 compounds, 16 beta, 17-dihydroxy-ent-kauran-19-oic acid showed significant activity against HIV replication in H9 lymphocyte cells with an EC50 value of 0.8 microgram/mL (therapeutic index > 5).
Abstract: Phytochemical analysis of the fruits of Annona squamosa yielded 12 known kaurane derivatives (1-11, 13) and two new kaurane diterpenoids, which have been named annosquamosin A (16 beta-hydroxy-17-acetoxy-ent-kauran-19-al) (12) and annosquamosin B (19-nor-ent-kaurane-4 alpha,16 beta,-17-triol) (14). The structures of the new compounds were established by spectral analyses and chemical evidence. Among these 14 compounds, 16 beta, 17-dihydroxy-ent-kauran-19-oic acid (2) showed significant activity against HIV replication in H9 lymphocyte cells with an EC50 value of 0.8 microgram/mL (therapeutic index > 5).
TL;DR: The MeOH extract of the aerial parts of Ardisia japonica was tested, and it showed moderate in vitro anti-HIV activity, and a new triterpenoid saponin was identified whose structure elucidation was accomplished by 1H-1H correlation spectroscopy and NMR experiments.
Abstract: As part of our screening of anti-AIDS agents from medicinal plants, the MeOH extract of the aerial parts of Ardisia japonica was tested, and it showed moderate in vitro anti-HIV activity. Reexamination to identify the compounds responsible for the anti-HIV activity revealed several known compounds and a new triterpenoid saponin (4) whose structure elucidation was accomplished by 1H-1H correlation spectroscopy (COSY, HOHAHA, ROESY) and 1H-13C heteronuclear correlation (HETCOR) NMR experiments. All of the isolated compounds were tested and, although none of the triterpenoid saponins was active, bergenin and norbergenin showed weak anti-HIV activity.
TL;DR: Dendroamide A, one of three new bistratamide-type cyclic hexapeptides from the terrestrial blue-green alga Stigonema dendroideum Fremy, exhibits multidrug-resistance reversing activity.
Abstract: Dendroamide A (1), one of three new bistratamide-type cyclic hexapeptides from the terrestrial blue-green alga (cyanobacterium) Stigonema dendroideum Fremy, exhibits multidrug-resistance reversing activity. The gross structures of the three compounds, dendroamides A-C, were determined by NMR and mass spectral analyses. Their absolute stereochemistries were determined by Marfey and chiral GC/MS analyses of derivatives formed from acid hydrolysis of the intact and ozonized peptides.
TL;DR: Cercophorins A-C (3-5), three novel isocoumarin derivatives with antifungal and cytotoxic activities, have been isolated from the coprophilous fungus Cercophora areolata, a colonist of porcupine dung.
Abstract: Cercophorins A−C (3−5), three novel isocoumarin derivatives with antifungal and cytotoxic activities, have been isolated from the coprophilous fungus Cercophora areolata (JS 166 = UAMH 7495), a colonist of porcupine dung. Two additional new isocoumarins, decarboxycitrinone (1) and 4-acetyl-8-hydroxy-6-methoxy-5-methylisocoumarin (2), and a known tricothecene mycotoxin, roridin E (6), were also obtained from this species. Compounds 1−6 were isolated from ethyl acetate extracts of mycelia and liquid cultures of C. areolata through bioassay-guided fractionation and are the first metabolites to be reported from a member of the genus Cercophora. Their structures were assigned on the basis of MS, selective INEPT, and 2D-NMR experiments.
TL;DR: Reaction of the fungal sesquiterpene illudin S with excess paraformaldehyde in dilute H2SO4 gives (hydroxymethyl)acylfulvene, which was more toxic than a precursor, acylful vene, but less toxic than the parent compound illud in S to HL 60 cells.
Abstract: Reaction of the fungal sesquiterpene illudin S with excess paraformaldehyde in dilute H2SO4 gives (hydroxymethyl)acylfulvene. The primary allylic hydroxyl thus formed can undergo very facile replacement by a variety of nucleophiles. (Hydroxymethyl)acylfulvene (MGI.114) was more toxic than a precursor, acylfulvene, but less toxic than the parent compound illudin S to HL 60 cells.
TL;DR: Three alkaloids isolated from Evodia rutaecarpa, to aorta smooth muscle demonstrated that they produce a vasodilatory effect on endothelium-intact rat aortA with equal potency.
Abstract: The vasoreactivity of dehydroevodiamine (1), evodiamine (2), and rutaecarpine (3), quinazoline alkaloids isolated from Evodia rutaecarpa, to aorta smooth muscle demonstrated that they produce a vasodilatory effect on endothelium-intact rat aorta with equal potency. Compound 3 produced a full (100%) nitric oxide-dependent vasodilatation, whereas 2 and 1 produced a partially endothelium-dependent effect, 50% and 10%, respectively. At the same time, I and 2 may also act by other mechanisms, including probably an alpha1-adrenoceptor blocking action and a 5-HT antagonizing action, respectively.
TL;DR: Analysis of the Philippine marine sponge Xestospongia ashmorica afforded four new manzamine congeners 1-4 and four known compounds 5-9, which exhibited insecticidal activity toward neonate larvae of the polyphagous pest insect Spodoptera littoralis and was also active against Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus.
Abstract: Analysis of the Philippine marine sponge Xestospongia ashmorica afforded four new manzamine congeners 1-4 and four known compounds 5 and 7-9. Compound 1 is the 6-deoxy derivative of manzamine X, while 2-4 are the N-oxides of manzamine J (5), 3,4-dihydromanzamine A (6), and manzamine A (7), respectively. The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic (1H, 13C, COSY, 1H-detected direct, and long-range 13C-1H correlations) and mass spectrometric (EI, FAB-MS, and electrospray ionization) data. Alkaloid N-oxide structures were confirmed by conversion to the corresponding tertiary bases by reduction with Zn/HCl. This is the first report of the occurrence of bioactive manzamine N-oxides in marine sponges. Compound 7 exhibited insecticidal activity toward neonate larvae of the polyphagous pest insect Spodoptera littoralis (with an ED50 of 35 ppm) when incorporated in artificial diet and offered to larvae in a chronic feeding bioassay. Compound 7 was also active against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus. Cytotoxicity was studied in vitro using L1578y mouse lymphoma cells. From the alkaloids studied, the N-oxides 3 and 4 were the most active (ED50 = 1.6 micrograms/mL) followed by compound 7 (ED50 = 1.8 micrograms/mL).
TL;DR: During a chemotaxonomic survey of Calophyllum extracts present in the National Cancer Institute's natural product repository, four new pyranocoumarins were isolated from extracts of C. lanigerum var.
Abstract: During a chemotaxonomic survey of Calophyllum extracts present in the National Cancer Institute's natural product repository, four new pyranocoumarins were isolated from extracts of C. lanigerum var. austrocoriaceum and C. teysmannii var. inophylloide (King.) P. F. Stevens (Clusiaceae). The structure elucidation and anti-HIV activity of calanolide E2 (4), cordatolide E (5), pseudocordatolide C (6), and calanolide F (9), along with a simple prenylated coumarin precursor (11), are described here.
TL;DR: Three known neolignans found for the first time in a species of the Piperaceae, were isolated from Piper decurrens via insecticidal bioassay-guided fractionation, along with a small quantity of a new related compound.
Abstract: 2,3-Dihydro-2-(4'-hydroxyphenyl)-3-methyl-5(E)-propenylbenzofuran (conocarpan) (1), 2-(4'-hydroxy-3'-methoxyphenyl)-3-methyl-5(E)- propenylbenzofuran (eupomatenoid-5) (2), and 2-(4'- hydroxyphenyl)-3-methyl-5(E)-propenylbenzofuran (eupomatenoid-6) (3), three known neolignans found for the first time in a species of the Piperaceae, were isolated from Piper decurrens via insecticidal bioassay-guided fractionation, along with a small quantity of a new related compound, 2,3-dihydro-5-formyl-2-(4'-hydroxyphenyl)-3-methylbenzofuran (decurrenal) (4), and 3,7,11,15-tetramethyl-2(E)-hexadecen-1-ol (trans-phytol).
TL;DR: The isolated coumarins showed marked activity as inhibitors of eicosanoid-release from ionophore-stimulated mouse peritoneal macrophages.
Abstract: Four coumarins were isolated from the EtOAc extract of the flower-tops of Santolina oblongifolia Boiss. (Compositae). They were identified as 7-methoxycoumarin (herniarin) (1), 6,7-dihydroxycoumarin (aesculetin) (2), 6-methoxy-7-glucosidylcoumarin (scopolin) (3), and 6-hydroxy-7-methoxycoumarin (scopoletin) (4). This is the first report of the isolation of aesculetin and scopolin from the genus Santolina. The isolated coumarins showed marked activity as inhibitors of eicosanoid-release from ionophore-stimulated mouse peritoneal macrophages.
TL;DR: Two new lignans, interiotherins A and B and B, along with two known lignan, angeloylgomisin R and schisantherin D, were isolated from Kadsura interior and their structures and stereochemistries were determined from spectral data.
Abstract: Two new lignans, interiotherins A (1) and B (2), along with two known lignans, angeloylgomisin R (3) and schisantherin D (4), were isolated from Kadsura interior. Their structures and stereochemist...
TL;DR: A MeOH extract of Swertia chirata found to inhibit the catalytic activity of topoisomerase I of Leishmania donovani was subjected to fractionation to yield three secoiridoid glycosides: amarogentin, amaroswerin, and sweroside.
Abstract: A MeOH extract of Swertia chirata found to inhibit the catalytic activity of topoisomerase I of Leishmania donovani was subjected to fractionation to yield three secoiridoid glycosides: amarogentin (1), amaroswerin (2), and sweroside (3). Amarogentin is a potent inhibitor of type I DNA topoisomerase from Leishmania and exerts its effect by interaction with the enzyme, preventing binary complex formation.
TL;DR: Niruriside showed specific inhibitory activity against the binding of REV protein to RRE RNA with an IC50 value of 3.3 microM; however, nirur iside did not protect CEM-SS cells from acute HIV infection at concentrations up to 260 microM using an XTT dye reduction assay.
Abstract: During the screening of natural products for their ability to inhibit the binding of HIV-REV protein to [33P]-labeled RRE RNA, one novel compound, niruriside (1), was isolated from the MeOH extract of the dried leaf of Phyllanthus niruri L. by bioassay-guided fractionation. The structure of niruriside was determined by spectroscopic methods. Niruriside showed specific inhibitory activity against the binding of REV protein to RRE RNA with an IC50 value of 3.3 microM; however, niruriside did not protect CEM-SS cells from acute HIV infection at concentrations up to 260 microM using an XTT dye reduction assay.
TL;DR: Sclerotiamide causes significant mortality and unusual physiological effects in dietary assays against the corn earworm Helicoverpa zea.
Abstract: Sclerotiamide (1), a new fungal natural product related to the paraherquamides, was isolated by bioassay-guided fractionation of antiinsectan organic extracts from the sclerotia of Aspergillus sclerotiorum (NRRL 5167). The structure was determined primarily through 1H-NMR, 13C-NMR, HMQC, and HMBC experiments. Sclerotiamide causes significant mortality and unusual physiological effects in dietary assays against the corn earworm Helicoverpa zea.
TL;DR: Two new naphthoquinones exhibit inhibitory activity against cytomegalovirus (CMV), with EC50 values of 0.02 and 0.22 microgram/mL, respectively, against human CMV.
Abstract: Two new naphthoquinones, rhinacanthin-C (1) and rhinacanthin-D (2), exhibit inhibitory activity against cytomegalovirus (CMV), with EC50 values of 0.02 and 0.22 μg/mL, respectively, against human C...