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Biomedical subjects

O Sticher

Publications and source records attributed to O Sticher.

At least 55 records · Page 3Linked to original sources
PubMed1997

Triterpene saponins from Cyclamen coum var. coum.

From the tubers of Cyclamen coum (Primulaceae) three new saponins, cyclaminorin (1), cyclacoumin (3) and mirabilin lactone (4) were isolated together with a known saponin, deglucocyclamin (2). The structures of the new compounds were established as 13 beta,28-epoxy-3 beta-(([beta-D-glucopyranosyl-(1-->2)]- [beta-D-glucopyranosyl-(1-->4)]-alpha-L-arabinopyranosyl) oxy) 16 alpha-hydroxy-olean-30-al (1), 13 beta,28-epoxy-3 beta-((([beta-D-xylopyranosyl-(1-->2) -beta-D-glucopyranosyl-(1-->4)]-[beta-D-glucopyranosyl-(1-->2)]- alpha-L-arabinopyranosyl)oxy)-16 alpha,23-dihydroxy-olean-30-al (3) and 16 alpha-hydroxy-3 beta-((([beta-D-xylopyranosyl-(1-->2)]- [beta-D-glucopyranosyl-1-->6)]-beta D-glucopyranosyl-(1-->4))- [beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl)-oxy) olean-12-eno-30,28-lactone (4). Structure elucidattions were accomplished using both spectral (NMR, MS, IR) and chemical methods.

Carbohydrate Sequence↗
PubMed1997

Cycloartane triterpene glycosides from the roots of Astragalus melanophrurius.

From the roots of Astragalus melanophrurius eight known saponins (1-8) were isolated. Based on spectral data (IR, 1H- and 13C-NMR, and FABMS), the structures were established as astrasieversianins II (1) and X (4), astragalosides I (2), II (3), IV (5) and VI (7), and cyclocanthosides E (6) and G (8). The isolates were evaluated in a broad range of bioassay systems and found to be inactive. Modest antibacterial activity was observed, however, as was immunomodulatory activity, as indicated by stimulation of isolated human lymphocytes.

Adjuvants, Immunologic↗
PubMed1996

Antibacterial hydroperoxysterols from Xanthosoma robustum.

Three new hydroperoxysterols, 24-hydroperoxy-4 alpha, 14 alpha- dimethylcholesta-8,25-dien-3 beta-ol, 25-hydroperoxy-4 alpha, 14 alpha-dimethylcholesta-8,23-dien-3 beta-ol and 25-hydroperoxycycloart-23-en- 3 beta-ol, have been isolated from the aerial parts of Xanthosoma robustum, besides 24-hydroperoxycycloart-25-en-3 beta-ol, 4 alpha, 14 alpha-dimethylcholesta-8,24-dien-3 beta-ol and cycloartenol. Additionally, the two new diols, 4 alpha, 14 alpha-dimethylcholesta-8,25-dien-3 beta, 24-diol and 4 alpha, 14 alpha-dimethylcholesta-8,23-dien-3 beta, 25-diol were obtained from the first two hydroperoxysterols, respectively, by reduction with triphenylphosphine. The structures have been defined by chemical and spectroscopic studies. The four hydroperoxysterols exhibited antibacterial activities against Escherichia coli, Bacillus subtilis and Micrococcus luteus.

Anti-Bacterial Agents↗
PubMed1996

Leonticins A-C, three octasaccharide saponins from Leontice kiangnanensis.

Three octasaccharide saponins, leonticins A, B, and C (1-3), were isolated from the tubers of Leontice kiangnanensis. Their structures were elucidated by a combination of chemical degradation and spectral methods including negative FABMS and NMR measurements as 3-O-beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosylhederagenin 28-O-alpha-L-rhamnopyranosyl (1-->4)-beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl(1-->4)-alpha-L-rhamnopyranosyl (1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (1), 3-O-[beta-D-xylopyranosyl(1-->3)-beta-D-galactopyranosyl(1-->4)-beta-D- glucopyranosyl (1-->3)][beta-D-glucopyranosyl(1-2)]-alpha-L-arabinopyranosyloleanoli c acid 28-O-alpha-L-rhamnopyranosyl (1-->4)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranoside (2), and 3-O-[beta-D-xylopyranosyl (1-->3)-beta-D-galactopyranosyl(1-->4)-beta-D-glucopyranosyl(1-->3)] [beta-D-glucopyranosyl(1-->2)]-alpha-L-arabinopyranosylechinocystic++ + acid 28-O-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl- (1-->6)-beta-D-glucopyranoside (3), respectively. The complete assignments of the proton and carbon resonances for 1-3 were achieved based on extensive 2D NMR analysis (DQF-COSY, TOCSY, ROESY, HSQC, and HMBC).

Anti-Inflammatory Agents↗
PubMed1995

Biological screening of traditional medicinal plants from Papua New Guinea.

Based on ethnopharmacological literature, 17 species of medicinal plants used in the traditional medicine in Papua New Guinea were collected. Extracts of different polarities were tested in a preliminary biological screening for their antimicrobial (Escherichia coli, Bacillus subtilis, Micrococcus luteus and Penicillium oxalicum) and molluscicidal activity against Biomphalaria glabrata as well as for their toxicity to brine shrimp. The pretreated plant extracts were also investigated for their ability to inhibit protein kinase C and tyrosine-specific protein kinase of epidermal growth factor receptor. Furthermore, all plants were screened for the presence of alkaloids.

Alkaloids↗
PubMed1995

Antibacterial triterpenoids from Dillenia papuana and their structure-activity relationships.

Two new oleanene-type triterpenoids, dillenic acids D and E, have been isolated from the leaves and stems of Dillenia papuana together with the new natural product 3-oxoolean-12-en-30-oic acid. Together with these compounds, the known compound, betulinic acid (3 beta-hydroxy-20(29)-lupen-28-oic acid) was isolated as the major component of the fractions studied. Dillenic acids D and E were characterized as 2,3-seco-2-oxoolean-12-en-3-methylester-30-oic acid and 1 alpha,3 beta-dihydroxyolean-12-en-30-oic acid and their nuclear magnetic resonance data were unambiguously assigned using two-dimensional nuclear magnetic resonance techniques. A comparison of antibacterial activities of these compounds with the earlier reported dillenic acids A-C indicated that, aside from a double bond in gamma- or delta-position to a carboxylic group, a ketone function in ring A of an oleanene-skeleton may be required for the observed activity.

Anti-Bacterial Agents↗
PubMed1995

Biological activities of cyanobacteria: evaluation of extracts and pure compounds.

A total of 80 lipophilic and hydrophilic extracts obtained from 20 samples of cultured freshwater and terrestrial cyanobacteria were investigated for their biological activities. Of all the extracts, 26% exhibited a significant lethal effect against brine shrimp. Out of 54 extracts tested for antimicrobial activity, 78% showed antibacterial and 45% antifungal activities. Of 30 extracts tested for cytotoxicity against KB cells, none was found to be active. Bioassay-guided fractionation of the lipophilic extracts of Fischerella ambigua led to the isolation of three compounds; ambigols A (1) and B (2), and tjipanazole D (3). Compounds 1 and 2 exhibited antibacterial, antifungal, cytotoxic, molluscicidal, and anti-inflammatory, and antiviral activities. Tjipanazole D (3) showed moderate antibacterial properties.

Animals↗
PubMed1994

Cytotoxic and antibacterial dihydrochalcones from Piper aduncum.

Bioactivity-guided fractionation of a CH2Cl2 extract from the leaves of Piper aduncum afforded three new dihydrochalcones, piperaduncins A [3], B [4], and C [5], as well as two known dihydrochalcones, 2',6'-dihydroxy-4'-methoxydihydrochalcone [1] and 2',6',4-trihydroxy-4'-methoxydihydrochalcone [2] (asebogenin), together with sakuranetin, anodendroic acid methyl ester, and the carotenoid lutein. The structures of the isolates were elucidated by spectroscopic methods, mainly 1D- and 2D nmr spectroscopy. The proposed stereochemistry for compound 4 was deduced by NOESY spectroscopy and the corresponding energy minimum was established by molecular modelling calculations and translated into a 3D structure.

Animals↗
PubMed1994

Inerminosides A and B, two novel complex iridoid glycosides from Clerodendrum inerme.

The leaves of Clerodendrum inerme have yielded two new iridoid biglycosides which have been characterized as 2'-O-[5"-O-(8-hydroxy-2,6-dimethyl-2(E)-octenoyl)-beta-D-apiofuranosy l]- mussaenosidic acid (inerminoside A) [1], and 2'-O-[5"-O-(8-hydroxy-2,6-dimethyl-2(E),6(E)-octadienoyl)-beta-D- apiofuranosyl]-8-epi-loganic acid (inerminoside B [2]), respectively. Structure elucidation was carried out both chemically and spectroscopically.

Africa↗
PubMed1994

Antibacterial triterpenoid acids from Dillenia papuana.

Three new oleanene-type triterpenoids, dillenic acids A [1], B [2], and C [3], and two known compounds, 3-oxoolean-1,12-dien-30-oic acid [4] (a new natural product) and the lupene derivative betulinaldehyde, have been isolated from the Papua New Guinean medicinal plant Dillenia papuana. The structures of the new compounds were elucidated as 2 alpha-hydroxy-3-oxoolean-12-en-30-oic acid, 2-oxo-3 beta-hydroxyolean-12-en-30-oic acid and 1 alpha-hydroxy-3-oxoolean-12-en-30-oic acid. The 1H- and 13C-nmr data of all new compounds were assigned unambiguously using a variety of 2D nmr experiments including 1H-1H-COSY, HMQC, HMBC, and NOESY experiments. Of these compounds, 1-4 showed antibacterial activities against Bacillus subtilis, Escherichia coli, and Micrococcus luteus.

Anti-Bacterial Agents↗
PubMed1994

Biological activities of selected marine natural products.

Sixty-nine natural products derived from Phaeophyta (brown algae), Rhodophyta (red algae), Porifera (sponges), Cnidaria (soft corals), and Mollusca (nudibranchs) were investigated for their cytotoxic, antimalarial, and antimicrobial effects. Fifty-six were found to mediate a positive response in one or more of these test systems.

Animals↗
PubMed1993

Periandrin V, a further sweet triterpene glycoside from Periandra dulcis.

A new sweet triterpene glycoside, periandrin V, was isolated from the roots of Periandra dulcis and identified as 3 beta-O-[beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl]-25 -al-olean-18(19)-en-30-oic acid on the basis of chemical and spectral evidence. The structure of an acid-rearranged product of periandrin V and the parent compound, periandrin I, was determined as 1(10-->25) abeo-3 alpha, 25 alpha-epoxy-olean-5(10), 18-dien-30-oic acid methyl ester.

Carbohydrate Sequence↗
PubMed1993

Two phenethyl alcohol glycosides from Scutellaria orientalis subsp. pinnatifida.

Two new phenethyl alcohol glycosides, darendoside A and B (= deacyl martynoside) were isolated from the methanolic extract of the aerial parts of Scutellaria orientalis subsp. pinnatifida, along with four known glycosides, syringin, martynoside, leucosceptoside A and verbascoside. On the basis of chemical and spectral evidence the structures of darendoside A and B were determined as beta-(4-hydroxyphenyl)ethyl O-beta-D-apiofuranosyl-(1-->2)-O-beta-D-glucopyranoside and beta-(3-hydroxy-4-methoxyphenyl)ethyl O-alpha-L-rhamnopyranosyl-(1-->3)-O-beta-D-glucopyranoside (= deacyl martynoside), respectively.

Carbohydrate Sequence↗
PubMed1993

Karsoside and scropolioside D, two new iridoid glycosides from Scrophularia ilwensis.

Two new iridoid glycosides, karsoside [1] and scropolioside D [2], were isolated from the aerial parts of Scrophularia ilwensis. Their structures were elucidated on the basis of chemical and spectral data as 6'-O-(beta-D-xylopyranosyl)-methylcatalpol and 6-O-[(2",4"-di-O-acetyl-3"-O-trans-cinnamoyl)-alpha-L-rhamnopyranosyl]- catalpol, respectively. Additionally, four known iridoids (aucubin, harpagide, 8-O-acetylharpagide, and ajugol), a phenylpropanoid glycoside (angoroside C), and two flavonoids (quercetin-3-O-rutinoside and kaempferol-3-O-rutinoside) were isolated and identified.

Acetylation↗
PubMed1993

A novel amino acid glycoside and three amino acids from Allium sativum.

A novel amino acid glycoside (-)-N-(1'-deoxy-1'-beta-D-fructopyranosyl)-S-allyl-L-cysteine sulfoxide [1], was isolated from a hydrophilic extract of the leaves of Allium sativum (Alliaceae), together with three known compounds: (+)-S-allyl-L-cysteine sulfoxide [2],(+)-S-methyl-L-cysteine sulfoxide [3], and (+)-S-(trans-1-propenyl)-L-cysteine sulfoxide [4]. The latter two substances were isolated for the first time from garlic. The structure elucidation of 1 was performed by extensive chemical, spectroscopic (ir, fabms, 1D and 2D(1)H- and (13)C-nmr measurements) and chromatographic experiments. For the first time, detailed nmr data and the unambiguous assignment of all (13)C-nmr data for compounds 2-4 were reported. Compound 1, the amino acid glycoside, revealed a significant inhibition of in vitro platelet aggregation induced by ADP and epinephrine, whereas none of the amino acids tested displayed any activity.

Amino Acids↗
PubMed1993

Quality of Ginkgo preparations.

A survey of known and of recently isolated constituents from Ginkgo leaves is given. The structures of flavonoids and terpene lactones which are considered to be the active compounds as well as their qualitative and quantitative determination in Ginkgo leaves and phytomedicines are presented. In the case of flavonoid analysis three selective methods worked out in our laboratories are described. The quality control of terpene lactones is discussed on the basis of a recently published paper. Finally, the standardization methods used for the quality control of Ginkgo preparations as well as the question as to whether or not phytomedicine generics--so called "phytogenerics"--exist, is discussed.

Carbohydrate Sequence↗