Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LACTONES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,135 records · Page 63Linked to original sources
PubMedDate not supplied

cis-clerodane diterpene lactones from Amphiachyris dracunculoides.

Four cis-ent-neoclerodane lactones, amphiacrolide A [2], amphiacrolide B [3], amphiacrolide C [4] and amphiacrolide D [5] were isolated from the aerial parts of Amphiachyris dracunculoides, and their structures established by physical and chemical methods. High field 1H- and 13C-nmr assignments were made for each compound and some of their derivatives by using one- and two-dimensional nmr techniques including nOe difference, COSY, and CH-correlation of one-bond and multiple bond (COLOC) relationships. A chemical correlation of the amphiacrolides to gutierolide [1], a compound with absolute stereochemistry determined by X-ray analysis, established the stereochemistry for the group. Consequently, a compound having reported properties identical with amphiacrolide D [5] must have its structure revised to contain the beta-faced epoxide. Amphiacrolide A [2] had not been reported previously.

Diterpenes↗
PubMedDate not supplied

A diterpenoid lactone from Aplysia juliana.

A new diterpenoid lactone, angasiol acetate [1], has been isolated from the sea hare Aplysia juliana collected from the Karachi coastline of the Arabian ocean. The structure, including the absolute configuration of 1, was determined by single-crystal X-ray diffraction and spectroscopic techniques.

Animals↗
PubMedDate not supplied

[Annomonysvin: a new cytotoxic gamma-lactone-monotetrahydrofuranyl acetogenin from Annona montana].

The structure of annomontacin [I], a novel monotetrayhydrofuran fatty acid gamma-lactone (acetogenin) isolated from the seeds of Amnona montana, was determined by spectral analysis. The cytotoxicities in vitro of annomontacin [I], annonacinone [2], and annonacin were measured against murine leukemia L1210, human breast adenocarcinoma MDA-MB231, and human breast carcinoma MCF7 cell lines and compared with adriamycin.

4-Butyrolactone↗
PubMedDate not supplied

Cytotoxic norditerpene lactones from Ileostylus micranthus.

Three new compounds 2-4 and two known compounds 1 and 5 have been isolated from the cytotoxic fraction of an extract from a New Zealand mistletoe, Ileostylus micranthus. Compounds 1-5 are shown to be norditerpene lactones and have strong cytotoxicity. The compounds are proposed to have been assimilated by the mistletoe from the host tree, Podocarpus totara.

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↗
PubMed1993

The isolation and structural elucidation of four novel triterpene lactones, pseudolarolides A, B, C, and D, from Pseudolarix kaempferi.

Four novel triterpene lactones, pseudolarolides A [1], B [2], C [3], and D [4], were isolated from the seeds of Pseudolarix kaempferi. Their structures and stereochemistry were elucidated from spectral data. Compound 2 shows potent cytotoxicity against three human cancer cell lines, KB (nasopharyngeal), A-549 (lung), and HCT-8 (colon), and against a murine leukemia cell line (P-388) with ED50 values of 0.49, 0.67, 0.73, and 0.79 micrograms/ml, respectively.

Animals↗
PubMed1993

New sesquiterpene alpha-methylene lactones from the Egyptian plant Jasonia candicans.

Extracts of the plant Jasonia candicans possess antimicrobial activity. ET2O/MeOH extracts were subjected to liquid chromatography, and several sesquiterpenes were isolated and identified including the known compounds confertin [1], 4,11(13)-eudesmadien-12-oic acid [2], and 11-eudesmen-4-ol [3]. Two new diol alpha-methylene lactone antimicrobial agents were identified from nmr and mass spectral data and X-ray crystallography as (4 alpha, 5 alpha, 8 beta, 10 beta)-4,10-dihydroxy-1,11(13)-guaidien-12,8-olide [4] and (4 alpha, 5 alpha, 8 beta, 10 alpha)-4,10-dihydroxyl-1,11 (13)-guaidien-12,8-olide[5], which differ in stereochemistry at the C-10 tertiary alcohol center.

Lactones↗
PubMed1993

Two new sesquiterpene lactones from Ceiba pentandra.

Two new sesquiterpene lactones showing moderate antimicrobial activity have been isolated from the root bark of Ceiba pentandra (Bombacaceae) in addition to the known compounds 8-formyl-7-hydroxy-5-isopropyl-2-methoxy-3-methyl-1,4-naphthaquinone+ ++ [1], and 7-hydroxycadalene [2]. The new compounds were characterized as 2,7-dimethoxy-5-isopropyl-3-methyl-8,1-naphthalene carbolactone [3] and 2-hydroxy-5-isopropyl-7-methoxy-3-methyl-8,1-naphthalene carbolactone [4] by chemical and spectroscopic studies.

Anti-Infective Agents↗
PubMed1996

Cis-clerodane diterpene lactones from Amphiachyris dracunculoides. 3.

Five cis-clerodane lactones, amphiacrolides J (1), K (2), L (3), M (4), and N (5), were isolated from the aerial parts of the composite Amphiachyris dracunculoides. The first four are new compounds, and the fifth was previously reported from another source. All compounds were assigned stereochemical structures based upon spectral and chemical data, including high-field 1D and 2D NMR for complete assignment of 1H- and 13C-NMR spectra. Amphiacrolide N (5) was converted to amphiacrolide J (1) by treatment with MeOH and TFA, and amphiacrolide L (3) was prepared from amphiacrolide B (9) by CrO3 oxidation to ketone 10 followed by its reduction with NaBH4.

Diterpenes↗
PubMed1997

Structure-cytotoxicity relationships of some helenanolide-type sesquiterpene lactones.

This study deals with the cytotoxicity of helenanolide-type (10 alpha-methylpseudoguaianolide) sesquiterpene lactones. We determined the influence of substitution patterns on the toxicity of 21 helenanolides to a cloned Ehrlich ascites tumor cell line, EN2. Within a series of helenalin esters, the acetate (2) and isobutyrate (3) were more toxic than helenalin itself (1). Esters with larger acyl groups (tiglate 4 and isovalerate 5) exhibited a decreased toxicity compared with the parent alcohol (1). Similar relationships were observed between the 6,8-diastereomer of helenalin, mexicanin I (6) and its acetate (7) and isovalerate (8). In contrast, cytotoxicity within a series of 11 alpha, 13-dihydrohelenalin esters (9-12) was shown to be directly related to the size and lipophilicity of the ester side chain, dihydrohelenalin (9) being the least toxic compound in this group. Investigation of several 2,3-dihydrohelenalin derivatives (13-21) with 2 alpha-hydroxy-4-oxo- and 2 alpha,4 alpha-dihydroxy- or -O-acyl-substituted cyclopentane rings (arnifolins and chamissonolides, respectively), for which no pharmacological data have been reported so far, revealed further interesting influences of the substitution pattern on cytotoxicity. The results may be interpreted in terms of lipophilicity and steric effects on the accessibility of the reactive sites considered responsible for biological activity.

Animals↗
PubMed1998

Two new ergostane-type steroidal lactones from Withania coagulans.

Two new withanolides (steroidal lactones) named coagulin F [27-hydroxy-14,20-epoxy-1-oxo-(22R)-witha-3,5,24-trienolide] (1) and coagulin G [17beta,27-dihydroxy-14,20-epoxy-1-oxo-(22R)-witha-2,5, 24-trienolide] (2) were isolated from the whole plant of Withania coagulans, and their structures were deduced by spectral analysis.

Acetylation↗
PubMed2001

Chain extension of sugar delta-lactones with the enolate of tert-butyl bromoacetate and elaboration into functionalized C-ketosides, C-glycosides, and C-glucosyl glycines.

[structure: see text] We describe the synthesis of a series of exocyclic sugar epoxides 1 prepared in a one-step procedure from sugar delta-lactones with the enolate of tert-butyl bromoacetate. Ring opening of the sugar oxiranes provides C-ketosides while reduction affords functionalized C-glycosides bearing an alpha-hydroxy ester moiety. The alpha-hydroxy ester can be converted into C-glucosyl glycine analogues 2.

Acetates↗
PubMed2002

K(2)CO(3)-catalyzed Michael addition-lactonization reaction of 1,2-allenyl ketones with electron-withdrawing group substituted acetates. An efficient synthesis of alpha-pyrone derivatives.

[reaction: see text] Alpha-pyrone derivatives were synthesized via the base catalyzed or promoted reaction of 1,2-allenyl ketones and electron-withdrawing group substituted acetates. The reaction was believed to proceed through a Michael addition C-C double-bond migration-lactonization process.

Acetates↗
PubMed2002

Kinetic resolution of racemic lactones by conjugate additions of allylic organolithium species: direct formation of three contiguous centers with high diastereo- and enantioselectivities.

[reaction: see text] Kinetic resolution of racemic alpha,beta-unsaturated lactones by the organolithium species produced from asymmetric lithiation of N-Boc-N-(p-methoxyphenyl)cinnamylamine provides conjugate addition products with three contiguous stereogenic centers in yields of 62-77% with diastereomeric ratios from 75:25 to >99:1 and enantiomeric ratios for the major diastereomers from 94:6 to 98:2.

Crystallography, X-Ray↗