Showing papers on "Diterpene published in 1993"
TL;DR: The chemical structures of four cyclic peptides, Lyciumins A-D, three acyclic diterpene glycosides, lyciumosides I-III and other three compounds, a tryptophan derivative glycoside, a monoterpene Glycoside and a steroidal glycosIDE isolated from Lycium chinense are elucidated by a combination of chemical, 1H- and 13C-NMR, and mass spectrometric studies.
Abstract: The chemical structures of four cyclic peptides, lyciumins A-D (1-4), three acyclic diterpene glycosides, lyciumosides I-III (5-7) and other three compounds, a tryptophan derivative glycoside (8), a monoterpene glycoside (9) and a steroidal glycoside (10) isolated from Lycium chinense, have been elucidated by a combination of chemical, 1H- and 13C-NMR, and mass spectrometric studies Lyciumins are interesting because of their monocyclic octapeptides containing a novel C-N linkage between tryprophan N1 and glycine C alpha
80 citations
TL;DR: Bioassay-directed fractionation of the MeCOEt extract of Porella cordeana yielded drimenin and aristolone, which were moderately toxic towards DNA-repair-deficient mutants of Saccharomyces cerevisiae.
Abstract: Bioassay-directed fractionation of the MeCOEc extract of Pwe&a cordeana yielded drimenin (l) and arisrolone 141, which were moderately toxic towards DNA-repair- deficient mutants of Saccharomyces cwevisiae. Three inactive sesquiterpenes, 7-ketoisodrimenin (2),7-ketoisodrimenin-5-ene 131, and norpinguisanolide, were also obtained. Compounds 2 and 3 are new. Bioassays that detect the presence of compounds that act by a specific biochemical mechanism likely to result in selective anticancer activity are becoming more frequently deployed in the biological screening of natural product extracts (1-4). One assay recently developed (4) utilizes DNA repair- or recombination-deficient mutants of the yeast Saccharomyces cerwisiae to detect the presence of compounds which induce DNA damage. This assay was recently employed in our laboratory to isolate three bioactive sterols from Pseudobersama mossambicensis (5). The present paper documents the further use of such an approach in the isolation of two moderately bioactive sesquiterpenes from the liverwort Porella cordeana (Hueb.) Moore (Porellaceae). Two novel but inactive drimane sesquiter- penes were also isolated. Previous phytochemical studies ofPo. cordeuna have afforded the sesquiterpenes pinguisanin, norpinguisone methyl ester, porellapinguisanolide, porellapinguisenone, spiropinguisan, and striatenone, and the diterpene perrottetianal
61 citations
TL;DR: Four new diterpenoids wikstroemioidin A–D, together with eight known compounds, isodonal, longikaurin D, adenolin B, effusanin A, effUSanin E, 5,3′,4′-trihydroxy-6,7,8-trimethoxy flavone, ursolic acid and sitosterol were isolated from the leaves of Isodon wik Stroemioides.
57 citations
TL;DR: The results obtained show that the free catechol grouping is essential for antimicrobial activity against Gram-positive bacteria and that activity appears to be independent of the closing position of the lactone group in the class A compounds.
49 citations
TL;DR: In this article, the E-and Z-isomers of 12,15-dihydroxylabda-8(17),13-dien-19-oic acid, 2α-hydroxycommunic acid as well as 15,16-bisnor-8,17-epoxy-13-oxolabd-11E-en-19 oic acid were determined by spectral methods.
49 citations
TL;DR: A linear diterpene, isolated from the brown alga Bifurcaria bifurcata collected on the Atlantic coasts from Morocco, has been characterized by spectral methods and chemical reactions as mentioned in this paper.
48 citations
TL;DR: In this article, the chloroform extract of Croton lechleri sap was chemically examined, and the major constituents characterized by mass and NMR spectroscopy, and four diterpenoids were found to be novel compounds possessing a clerodane skeleton.
47 citations
TL;DR: Two new labdane diterpenes, namely preleoheterin and leoheheterin, have been isolated from Leonurus heterophyllus as mentioned in this paper, and the previously known hispanolone and galeopsin have also been found in the same source.
44 citations
42 citations
TL;DR: Six new cembrane derivatives of α-methylene-δ-lactone derivatives were isolated from the lipid extract of the Caribbean gorgonian Eumicea mammosa, and the structures of these were determined by means of spectroscopic analyses.
Abstract: Eleven cembrane-type diterpenes were isolated from the lipid extract of the Caribbean gorgonian Eumicea mammosa. Of these, four α-methylene-δ-lactone derivatives, 1-4, and one α-methylene-γ-lactone, 5, had been previously isolated from various gorgonians. The structures of six new cembrane derivatives, eupalmerone {7}, pseudoplexauric acid methyl ester {8}, (7E,11E)-(1S,3S,4R)-3,4;15,17-diepoxycembra7,11-diene {11}, (-)-eunicenone {12}, cembranoid chlorohydrin 14, and diketone 15, were determined by means of spectroscopic analyses, and compounds 7 and 8 were chemically correlared with known cembranoid diterpenes eupalmerin {2} and pseudoplexaurol {9}, respectively
38 citations
TL;DR: In this paper, two new diterpenes, orthosiphols D and E, were isolated from the aerial parts of Orthosiphon stamineus and the structures of the new compounds were elucidated mainly by spectroscopic methods.
TL;DR: In this paper, a rearranged abietane skeleton of cyrtophyllone A (1) and B (2) was characterized using spectral analysis (UV, IR, MS, two dimensional (2D) NMR and CD) and X-ray diffraction.
Abstract: Tow novel abietane derivatives, cyrtophyllones A (1) and B (2), together with six known compounds, teuvincenone F (3), unicinatone (4), sugiol (5), friedelin (6), clerodolone (7), stigmasta-5, 22, 25-trien-3β-ol (8) and clerosterol (9), were isolated from the stem of Clerodendron cyrtophyllum. One of the abietane diterpenes, cyrtophyllone A, possesses a rearranged-abietane skeleton wich contains a 17(15-16)-abeo-abietane framework. The stereo-structure proposed for 1 was characterized as 16(S)-12, 16-epoxy-11, 14-dihydroxy-6-methoxy-17(15-16)-abeo-abieta-5, 8, 11, 13-tetraen-7-one on the basis of spectral analysis (UV, IR, MS, two dimensional (2D) NMR and CD) and X-ray diffraction. The structure of 2 was also characterized as (+)-11, 12, 16-trihydroxy-abieta-8, 11, 13-trien-7-one by a combination of spectroscopic comparison with sugiol.
TL;DR: In this paper, the roots of Solidago canadensis were investigated for the isolation of seven clerodane-type diterpenes related to kolavenic acid.
TL;DR: The essential oil of Ageratum conyzoides L. (Asteraceae) growing in Reunion (Indian Ocean) was investigated using capillary GC and GC-MS.
Abstract: The essential oil of Ageratum conyzoides L. (Asteraceae) growing in Reunion (Indian Ocean) was investigated using capillary GC and GC–MS. Two main components 7-methoxy-2,2-dimethylchromene (Precocene I) and β-caryophyllene, a large number of terpenoids and some chromenes are reported. Two new compounds, coumarin and phytol (a diterpene alcohol), were identified.
TL;DR: The remaining chinanetype diterpene having an isopropyl group at C-11 is first reported and Occurrence of all four types of diterpenes in this plant is significant.
TL;DR: In this paper, five new furanoid diterpene glycosides, named borapetoside C (1), D (2), E (3), F (4), and G (5), were isolated from the stems of Tinospora tuberculata Beumee (Menispermaceae).
TL;DR: In this article, sandaracopimaradien-9α-ol-1-one, sandararcopimadien -1α,6β, 9α-triol and sandaraceradien 1α,9α -diol have been isolated from the rhizomes of Kaempferia sp.
TL;DR: Three new natural diterpenes: 5,6-didehydro-7-hydroxy-taxodone (1), 17-hydroxcryptotanshinone (2) and salvicanaraldehyde (4) plus the known compounds: taxodione, taxodone, cryptotaninone (3), 7α,hydroxyroyleanone, ferruginol, 6,7-dimethylsalvicanol (6,7)-dimethyl salvicanolin (7), demethylsalvanicanol,
TL;DR: Extracts of timber of Erythroxylum pictum yielded sitosterol and 29 diterpenes, of which 15 were new and 4,5 seco-ro
TL;DR: From the roots of the medicinal plant Iostephane heterophylla, two new bisabolenes and a new ent -kaurenoid diterpene, along with xanthorrhizol, eight polycyclic diterpenes, scopoletin and 8-hydroxy-6-acetyl-2,2-dimethyl-chromene were isolated.
TL;DR: The new natural diterpenes, 16acetoxycarnosic acid, 16-hydroxy-20-deoxocarnosol and 16hydroxyrosmanol plus the known compounds were isolated from the aerial parts of Salvia mellifera as mentioned in this paper.
TL;DR: Two new C-16 hydroxylated abietane diterpenes and the known compounds cryptotanshinone and isopimaradiene have now been isolated from Salvia mellifera and identified by rigorous spectroscopic and X-ray crystallographic analyses as mentioned in this paper.
TL;DR: The structure of (3 R )-serrulat-14-ene-3,7,8,20-tetraol, a compound suitable for conversion into the seco -pseudopterosins, was established on the basis of spectroscopic and chemical evidence.
TL;DR: These results established that the natural compound (+)-1, a platelet aggregation inhibitor, has a normal absolute stereochemistry like that of manool.
Abstract: Enantioselective total synthesis of the labdane diterpene (-)-1, was achieved starting from the R-(-)-enantiomer of the Wieland-Miescher ketone (3). The enantiomer (+)-1 was obtained by partial synthesis via microbial transformation of sclareol (24). These results established that the natural compound (+)-1, a platelet aggregation inhibitor, has a normal absolute stereochemistry like that of manool (2). The B-norlabdane-related compound 44 was also synthesized using a novel ring contraction reaction.
TL;DR: From the leaves of Conyza trihecatactis, the labdane-type diterpenes and diterpene xylosides ent-sclareol, ent-3β-hydroxymanool, and ent-manool 13-O-β- d -xylopyranoside are isolated.
TL;DR: Aerial parts of Fagonia bruguieri afforded two new erythroxan-type diterpenes: 15,16-dihydroxy-7-oxo- cis-ent -eryTHrox-3-ene (fagonone) and 16- O -acetylfagonone, the first reported occurrence of diterPenes in the family Zygophyllaceae and the first known ent -erystroxane.
TL;DR: The isolation and structures of a new tricyclic diterpene 2 and a new daucadiene sesquiter pene hydrocarbon 3 from the sponge Higginsia sp.
Abstract: The isolation and structures of a new tricyclic diterpene 2 and a new daucadiene sesquiterpene hydrocarbon 3 from the sponge Higginsia sp. are described. Revision of the relative stereochemistry of a previously reported daucadiene hydrocarbon is suggested
TL;DR: The rhizomes of Hedychium coronarium (Zingiberaceae) have yielded two new diterpenes which have been identified by spectroscopic methods, notably long-range heteronuclear coupling (HMBC) as discussed by the authors.
Abstract: The rhizomes of Hedychium coronarium (Zingiberaceae) have yielded two new diterpenes which have been identified by spectroscopic methods, notably long-range heteronuclear coupling (HMBC). Coronarin-D methyl ether is a labdane diterpene typical of those previously isolated from this species. The second compound, identified as 14,15,16-trinorlabda-8(17),11-(E)-dien-13-al, appears to be an unusual trinorditerpene catabolite which could be formed by degradation of the normal labdanes produced by this species.
TL;DR: Four new biologically active diterpenes, trifoliones A, B, C, and D, were isolated from the tuber of Sagittaria trifolia L and exhibited inhibitory effects on the histamine release from rat mast cells induced by compound 48/80 or calcium ionophore A-23187.
Abstract: Four new biologically active diterpenes, trifoliones A, B, C, and D, were isolated from the tuber of Sagittaria trifolia L. together with three new glycosides, sagittariosides a and b and arabinothalictoside. Their stereostructures were determined on the basis of chemical and physicochemical evidence which included the application of a modified Mosher's method and an exciton chirality method. Trifoliones A, B, C, and D exhibited inhibitory effects on the histamine release from rat mast cells induced by compound 48/80 or calcium ionophore A-23187.
TL;DR: In this paper, the structures of spiramines E (1), F (2) and G (3) were elucidated by chemical and spectroscopic means, and the structure of spiramine E was shown to be stable.
Abstract: Structures of spiramines E (1), F (2) and G (3) were elucidated by chemical and spectroscopic means