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Biomedical subjects

O Sticher

Publications and source records attributed to O Sticher.

At least 19 recordsLinked to original sources
PubMed1992

Balanitoside, a furostanol glycoside, and 6-methyldiosgenin from Balanites aegyptiaca.

In addition to a known spirostanol glycoside, balanitin-3, and a new sapogenol, 6-methyldiosgenin, a new furostanol saponin, balanitoside has been isolated from the fruits (mesocarp) of Balanites aegyptiaca. The structure of the glycoside has been determined as 26-O-beta-D-glucopyranosyl-3 beta, 22,26-trihydroxy-furost-5-ene 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D- glucopyranosyl-(1-->4)-beta-D-glucopyranoside, on the basis of spectroscopic and chemical evidence.

Carbohydrate Sequence↗
PubMed1992

Four new antibacterial sesterterpenes from a marine sponge of the genus Luffariella.

The structures of four new sesterterpenoid compounds 1-4 isolated from a marine sponge of the genus Luffariella, collected from The Great Barrier Reef, Australia, have been determined by analysis of their 1H-nmr, 13C-nmr, ir, uv, and eims spectral data. The new metabolites 1-4 were found to co-occur with the compounds manoalide, secomanoalide, Z-neomanolaide [5], and E-neomanoalide.

Animals↗
PubMed1992

New phenolic glucosides from the leaves of Eurya tigang.

Three new compounds, 6'-O-coumaroyl-1'-O-[2-(4-hydroxyphenyl)ethyl]-beta-D-glucopyra nos ide [1] (eutigoside A), 6'-O-coumaroyl-1'-O-[2-(1-hydroxy-4-oxo-2,5-cyclohexadien-1- yl)ethyl]-beta-D-glucopyranoside [2] (eutigoside B), and 6'-O-cinnamoyl-1'-O-[2-(1-hydroxy-4-oxo-2,5-cyclohexadien-1-yl)eth yl]- beta-D-glucopyranoside [3] (eutigoside C) have been isolated from the leaves of Eurya tigang, along with other known compounds (afzelin, quercitrin, p-coumaric acid, methyl-alpha-D-fructofuranoside, isorengyol, and euryanoside). Their structures were determined by chemical and spectroscopic methods (uv, ir, ms, 1H-1H COSY, and 1H-13C COSY).

Animals↗
PubMed1992

Antimalarial activity of sesquiterpenes from the marine sponge Acanthella klethra.

Five sesquiterpenoids containing isonitrile or isothiocyanate groups were isolated from the sponge Acanthella klethra. Compounds 1 and 2 were identified as axisonitrile 3 and the corresponding isothiocyanate derivative, respectively. Compounds 3-5 were found to be eudesmane sesquiterpenes. None of these compounds was cytotoxic toward cultured KB-3 cells, but varying degrees of activity were observed with cultured Plasmodium falciparum. Compound 1 demonstrated greatest promise as an antimalarial agent.

Animals↗
PubMed1992

Indole alkaloids with in vitro antiproliferative activity from the ammoniacal extract of Nauclea orientalis.

Nine angustine-type alkaloids were isolated from ammoniacal extracts of Nauclea orientalis L. (Rubiaceae). Three of them, 10-hydroxyangustine and the two diastereoisomeric 3,14-dihydroangustolines, have not been described in the literature thus far. The structures of the isolates were determined with spectroscopic methods, mainly 1D- and 2D-NMR spectroscopy. The compounds were found to exhibit in vitro anti-proliferative activity against the human bladder carcinoma T-24 cell line and against EGF (epidermal growth factor)-dependent mouse epidermal keratinocytes. By using overpressure layer chromatography, it was shown that minor quantities of these alkaloids occur in dried Nauclea orientalis leaves. The use of ammonia in the extraction process results in a significant increase in the formation of angustine-type alkaloids from strictosamide-type precursors.

Alkaloids↗
PubMed1991

Phlinosides D and E, phenylpropanoid glycosides, and iridoids from Phlomis linearis.

Two new phenylpropanoid glycosides, phlinosides D and E were isolated from the methanolic extract of the aerial parts of Phlomis linearis, along with the known iridoid glucosides, lamiide, ipolamiide and auroside (= 5-hydroxy-8-epiloganin). On the basis of chemical and spectral evidence the structures of phlinosides D and E were determined as 3,4-dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1----2)-al pha-L-rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside and 3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1----2) -alpha-L- rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside, respectively.

Acetylation↗
PubMed1991

New indole alkaloid glycosides from Nauclea orientalis.

Two new indole alkaloid glycosides, 10-hydroxystrictosamide and 6'-O-acetylstrictosamide, as well as the known alkaloids strictosamide and vincosamide were isolated from the leaves of Nauclea orientalis L. The structures of the isolated compounds were determined using spectroscopic methods, mainly 1D- and 2D-NMR spectroscopy.

Animals↗
PubMed1990

Phlinosides A, B and C, three phenylpropanoid glycosides from Phlomis linearis.

Three new phenylpropanoid glycosides, phlinosides A, B and C were isolated from a methanolic extract of the aerial parts of Phlomis linearis. On the basis of chemical and spectral evidence their structures were determined as 3,4-dihydroxy-beta-phenylethoxy-O-beta-D-glucopyranosyl-(1----2)-a lpha-L- rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside, 3,4 dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1----2)-alpha- L- rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside and 3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1----2) -alpha- L-rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside, respectively.

Glycosides↗
PubMed1987

Rapid and sensitive determination of dehydroascorbic acid in addition to ascorbic acid by reversed-phase high-performance liquid chromatography using a post-column reduction system.

An improved procedure for the direct determination of l-dehydroascorbic acid (DHAA), in addition to l-ascorbic acid (AA), has been developed. The two biologically active forms of vitamin C were separated using reversed-phase high-performance liquid chromatography. DHAA was reduced to AA with dithiothreitol (DTT) in a post-column reaction system. Complete conversion was achieved at 50 degrees C using a 1-ml reaction coil. Recoveries were in the range of 95-99% and both forms could be detected spectrophotometrically at 267 nm with high sensitivity. Reproducible results [relative standard deviations 2.4% (DHAA) and 1.0% (AA), n = 5] were obtained when the method was applied to the analysis of rose hip samples.

Ascorbic Acid↗