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Biomedical subjects

J L McLaughlin

Publications and source records attributed to J L McLaughlin.

At least 91 records · Page 5Linked to original sources
PubMed1994

Kneglomeratanol, kneglomeratanones A and B, and related bioactive compounds from Knema glomerata.

One new phenylalkyl phenol, kneglomeratanol [1], and two new acetophenones, kneglomeratanones A [2] and B [3], together with ten known compounds, 3-(12'-phenyldodecyl)-phenol [4], 3-(10'-phenyldecyl)-phenol [5], 5-pentadecylresorcinol [6], 5-(10'-phenyldecyl)-resorcinol [7], 5-(12'-phenyldodecyl)-resorcinol [8], 2,4-dihydroxy-6-(10'-phenyldecyl)-acetophenone [9], 2-hydroxy-6-(12'-phenyldodecyl)-benzoic acid [10], formononetin, biochanin A, and 8-O-methylretusin, have been isolated from the stem bark of Knema glomerata. Brine shrimp lethality was used for the activity-directed chromatographic fractionations. All of these compounds showed moderate but significant toxicities to three human tumor cell lines and inhibited the growth of crown gall tumors on discs of potato tubers.

Acetophenones↗
PubMed1994

Bioactive annonaceous acetogenins from the bark of Xylopia aromatica.

Bioactive Annonaceous acetogenins have been isolated from the EtOH extract of the bark of Xylopia aromatica by bioactivity-directed fractionation using lethality to brine shrimp. These acetogenins include xylopianin [1 , xylopiacin [2], and xylomaticin [3], which are three new mono-tetrahydrofuran ring type acetogenins, in addition to the known compounds, annomontacin, gigantetronenin, gigantetrocin A, and annonacin. Compounds 1 and 2 are unusual in having hydroxylation at C-8; 3 has the same functionalities as annonacin but with 37 carbons instead of 35 carbons. The structures were elucidated by spectral analysis of the parent compounds and/or simple chemical derivatives. These acetogenins showed cytotoxicities, comparable to adriamycin, against three human solid tumor cell lines.

Animals↗
PubMed1994

Two new bioactive monotetrahydrofuran Annonaceous acetogenins from the bark of Xylopia aromatica.

Xylopien [1] and xylomatenin [2], two new bioactive monotetrahydrofuran Annonaceous acetogenins, have been isolated from an EtOH extract of the bark of Xylopia aromatica, using bioactivity-directed fractionation employing lethality to brine shrimp. These new compounds each have a double bond in the hydrocarbon chain and have been identified as C-23, C-24 dehydro analogs of xylopiacin and xylomaticin. Their structures were elucidated by spectral analyses of the parent compounds and/or simple chemical derivatives. Their absolute stereochemistries have been established by 1H- and 2D nmr experiments utilizing the production of Mosher esters. These acetogenins showed cytotoxic potencies superior to adriamycin against three human solid tumor cell lines.

4-Butyrolactone↗
PubMed1993

Mode of action of bullatacin: a potent antitumor and pesticidal annonaceous acetogenin.

Bullatacin, a compound isolated from plants of the Annonaceae, and its analogues show in vivo potential as antitumor agents based on their efficacy in normal mice bearing L1210 murine leukemia and athymic mice bearing A2780 conventional ovarian cancer xenografts. These compounds also have interesting potential as insecticides and inhibit respiration in insect-derived Sf9 cells with high potency. Their toxicity in both cases probably arises from their strong inhibition of mitochondrial electron transport with a specific action at complex I.

Animals↗
PubMed1993

Biologically active acetogenins from stem bark of Asimina triloba.

In continuing our research with cytotoxic and pesticidal components from the stem bark of the North American paw paw, Asimina triloba, the novel cytotoxic monotetrahydrofuran Annonaceous acetogenins, cis- and trans-annonacin-A-one, cis- and trans-gigantetrocinone and cis-isoannonacin, in addition to the known compounds, trans-isoannonacin and squamolone, have been identified. Brine shrimp lethality testing was used to direct the fractionation. The structures were elucidated by spectral analysis and/or chemical synthesis. These acetogenins have potent cytotoxicities against the human tumour cell lines of A-549 (lung carcinoma), MCF-7 (breast carcinoma) and HT-29 (colon adenocarcinoma).

Animals↗
PubMed1993

30-, 31-, and 32-hydroxybullatacinones: bioactive terminally hydroxylated annonaceous acetogenins from Annona bullata.

From Annona bullata, three more pairs of new ketolactone Annonaceous acetogenins were isolated by bioactivity-directed isolation. They are hydroxylated adjacent bistetrahydrofuran (THF) acetogenins and are named (2,4-cis and trans)-32-hydroxybullatacinone (1 and 2), (2,4-cis and trans)-31-hydroxybullatacinone (3 and 4), and (2,4-cis and trans)-30-hydroxybullatacinone (5 and 6). The structures were elucidated by analysis of the 1H- and 13C-nmr spectra of 1-6 and their acetates and the ms of their tri-trimethylsilyl (TMSi) derivatives as compared with bullatacinone [7]. This is the first time that Annonaceous acetogenins with OH groups at successive positions near the end of the aliphatic chain have been reported. All of the new compounds showed potent activities in the brine shrimp lethality test and against human solid tumor cells in culture, with selectivities exhibited especially toward the colon cancer cell line (HT-29).

Animals↗
PubMed1993

Kinase inhibitors from Polygonum cuspidatum.

Bioassay-directed fractionation of a medicinal plant, Polygonum cuspidatum (Polygonaceae), has led to the discovery of a hydroxystilbene, resveratrol [1], as an inhibitor of a protein-tyrosine kinase (p56lck) partially purified from bovine thymus. Both trans and cis isomers of resveratrol possess comparable protein-tyrosine kinase inhibitory activity. Comparison of the IC50 values of resveratrol for protein-tyrosine kinase inhibitory activity with those of piceid (resveratrol-O3-beta-glucoside) [2] and resveratrol-O4'-beta-glucoside [3] shows the requirement of free hydroxyl groups on both phenyl rings for the protein-tyrosine kinase inhibition. Protein kinase C inhibitory analysis suggests the requirements of two free hydroxyl groups on one phenyl ring only.

Animals↗
PubMed1993

Guinea pig maximization test of the bark extract from pawpaw, Asimina triloba (Annonaceae).

Several acetogenins, characteristic of the Annonaceae, have been found to exhibit pesticidal and feeding-deterrent activities against a variety of pests and are undergoing commercial development as pesticides. The sensitizing potential of one of these plants, pawpaw, Asimina triloba Dunal, was examined in the current study. The potential of Fraction F020 (a pesticidal crude extract of pawpaw stem bark) to sensitize and elicit an allergic contact dermatitis response was determined by using a modified guinea pig maximization test (GPMT). Fraction F020 is a weak sensitizer and the active compound, asimicin, a trihydroxy-bistetrahydrofuran fatty acid gamma-lactone, is a weak irritant.

Animals↗
PubMed1992

Bullatencin, 4-deoxyasimicin, and the uvariamicins: additional bioactive Annonaceous acetogenins from Annona bullata Rich. (Annonaceae).

Additional bioactive Annonaceous acetogenins have been isolated from the EtOH extract of the bark of Annona bullata Rich. by bioactivity-directed fractionation using lethality to brine shrimp. These acetogenins include bullatencin, a new single tetrahydrofuran acetogenin having a double bond in the hydrocarbon chain; 4-deoxyasimicin, a new adjacent bis-tetrahydrofuran acetogenin; and the uvariamicins, an isomeric mixture of four single tetrahydrofuran acetogenins showed selective cytotoxicities for certain human solid tumor cell lines comparable to or better than adriamycin.

Animals↗
PubMed1992

Biologically active gamma-lactones and methylketoalkenes from Lindera benzoin.

Brine shrimp lethality-directed fractionation of the 95% EtOH extract of ripe berries from Lindera benzoin led to the isolation of three new C21 alkane-alkene gamma-lactones designated isolinderanolide, isolinderenolide, and linderanolide as well as the known series of C17 and C19 obtusilactones (isoobtusilactone A, obtusilactone A, isoobtusilactone, and obtusilactone) previously isolated from Lindera obtusiloba. The novel (6Z,9Z,12Z)-pentadecatrien-2-one, the known (6Z,9Z)-pentadecadien-2-one, and the known (+)-(Z)-nerolidol were also isolated as bioactive compounds. The structural elucidation and biological activities of these compounds are reported.

Animals↗
PubMed1992

Additional bioactive compounds and trilobacin, a novel highly cytotoxic acetogenin, from the bark of Asimina triloba.

Fractionation of the EtOH extract of the bark of Asimina triloba, monitoring by brine shrimp lethality, has led to the isolation and structural elucidation of a novel highly cytotoxic Annonaceous acetogenin, trilobacin [1], in addition to six known compounds: asimicin 2], bullatacin [3], bullatacinone [4], N-p-coumaroyltyramine [5], N-trans-feruloyltyramine [6], and (+)-syringaresinol [7]. Acetogenin 1 was identified as a diastereomer of asimicin [2] by spectral and chemical methods, and both 1 and 2 showed potent and selective cytotoxicities in the NCI human tumor cell line screen.

Antineoplastic Agents, Phytogenic↗
PubMed1992

Emodin, a protein tyrosine kinase inhibitor from Polygonum cuspidatum.

Bioassay-directed fractionation of a Chinese medicinal plant, Polygonum cuspidatum (Polygonaceae), has led to the discovery of an anthraquinone, emodin [1], as a strong inhibitor of a protein tyrosine kinase (p56lck) partially purified from bovine thymus. Comparison of the IC50 values of emodin for protein tyrosine kinase inhibitory activity with physcion [2] and emodin-O8-D-glucoside [3], also isolated from the same plant, reveal the importance of the hydroxyl groups at C-6 and C-8 for the observed activity.

Animals↗
PubMed1992

Bioactive constituents from the twigs of Asimina parviflora.

The EtOH extract of Asimina parviflora (Annonaceae), when subjected to activity-directed fractionation using lethality to brine shrimp, led to the isolation and identification of five bioactive compounds: asimicilone [1], which is a new 2-quinolone alkaloid, 6-cis-docosenamide [2], which is a new amide of a long hydrocarbon chain fatty acid, and three known compounds, asimicin, (+)-syringaresinol, and beta-sitosterol-beta-D- glucopyranoside. The structure determination of the new alkaloid was performed by extensive nmr analyses, including HMQC and HMBC. Selective cytotoxic activities of these compounds in three human solid tumor cell lines are also reported.

Animals↗
PubMed1992

Gigantetronenin and gigantrionenin: novel cytotoxic acetogenins from Goniothalamus giganteus.

Gigantetronenin [1] and gigantrionenin [6], two new monotetrahydrofuran Annonaceous acetogenins each possessing a double bond along the hydrocarbon chain, have been isolated from the bark of Goniothalamus giganteus by the use of brine shrimp lethality for bioactivity-directed fractionation. The structures were elucidated based on spectroscopic and chemical methods. Compounds 1 and 6 both show selective and potent cytotoxicities to human tumor cells in culture as well as toxicity to brine shrimp. A known cytotoxic acetogenin, annomontacin [11], was also isolated from this plant. The biogenetic pathway of the acetogenins from G. giganteus is discussed.

Animals↗