ent-Labdane diterpenes from the aquatic plant Potamogeton pectinatus

Four new ent-labdane diterpenes were isolated from the freshwater aquatic plant Potamogeton pectinatus, together with two known furano-ent-labdanes. The new compounds were assigned the structures methyl-15,16-epoxy-12(R)-acetoxy- 8(17), 13(16),14-ent-labdatrien-19-oate,15,16-epoxy-12(R)-acetoxy-8(17), 13(16),14-ent-labdatrien-19-oic acid, 8(17),13-ent-labdadien-15 --> 16-lactone-19-oic acid and 16-hydroxy-8(17),13-ent-labdadien-15,16-olid-19-oic acid by spectroscopic means. Some of these labdanes showed a strong algicidal activity against Raphidocelis subcapitata.     

Identification of the polar constituents of Potamogeton species by HPLC-UV with post-column derivatization, HPLC-MSn and HPLC-NMR, and isolation of a new ent-labdane diglycoside

The polar extracts of Potamogeton pectinatus, P. lucens, P. perfoliatus and P. crispus (Potamogetonaceae) were analyzed by HPLC-UV-MS and their chromatographic profiles were very similar. The polar constituents of P. pectinatus were more exhaustively investigated by HPLC-UV with post-column derivatization, HPLC-MS(n) and HPLC-NMR, which allowed the on-line identification of various known flavones (dereplication). One of these compounds, luteolin 3'-O-glucoside, has never been characterized in the Potamogeton genus. The HPLC-UV-MS and HPLC-NMR analyses revealed also the presence of ent-labdane diterpene glycosides in the polar extracts of P. pectinatus and P. lucens and led to the isolation of a new ent-labdane diglycoside from P. pectinatus, beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-15,16-epoxy-12-oxo-8(17),13(16),14-ent-labdatrien-19-oate.     

Lactone diterpenes from the aquatic plant Potamogeton natans

Four lactone diterpenes and two related glucosides with a labdane skeleton have been isolated from the aquatic plant Potamogeton natans. The structures of three new compounds were determined as 19-acetoxy-20-oxo-8(17),13-ent-labdadien-15-->16 lactone, 8(17), 13-ent-labdadien-15-->16,19-->20 dilactone and 6'-acetyl-19-glucopyranosyloxy-8(17),13-ent-labdadien-15-->16 lactone, respectively, by means of spectral analysis. Antialgal assays showed inhibitory activity for some compounds.     

ent-Clerodane diterpenes and other constituents from the liverwort Adelanthus lindenbergianus (Lehm.) Mitt

Eleven ent-clerodanes, 13-hydroxy-cis-ent-cleroda-3,14-diene, 15-hydroxy-cis-ent-cleroda-3,13(E)-diene, 1beta,12:15,16-diepoxy-cis-ent-cleroda-13(16),14-dien-18alpha,6alpha-olide, 8beta,12:15, 16-diepoxy-cis-ent-cleroda-13(16),14-dien-18alpha,6alpha-olide, 1beta,16:15,16-diepoxy-cis-ent-cleroda-12,14-dien-18alpha,6alpha-olide, 7beta,12:8beta,12-diepoxy-15-hydroxy-cis-ent-cleroda-13-en-16,15:18alpha,6alpha-diolide, 7beta,12:8beta,12-diepoxy-16-hydroxy-cis-ent-cleroda-13-en-15,16:18alpha,6alpha-diolide, 1alpha-acetoxy-8beta,12-epoxy-15-hydroxy-cis-ent-cleroda-13-en-16,15:18alpha,6alpha-diolide, 1beta,12-epoxy-16-hydroxy-cis-ent-cleroda-13-en-15,16:18alpha,6alpha-diolide, 8beta,12-epoxy-15-hydroxy-trans-cleroda-13-en-16,15:18alpha,6alpha-diolide, 8beta,12-epoxy-16-hydroxy-trans-cleroda-13-en-15,16:18alpha,6alpha-diolide along with the known clerodane diterpenes anastreptin and orcadensin have been isolated from the liverwort Adelanthus lindenbergianus (Lehm.) Mitt. Furthermore, three eudesmane sesquiterpenes together with the known (-)-1beta,10-epoxyaristolan, 3,4-seco-4(23),20(29)-lupadien-3,28-dicarboxylic acid dimethyl ester and two acetophenone derivatives were identified by spectroscopic methods, essentially MS and NMR experiments.     

Chemosystematic investigations of irregular diterpenes in Anisotome and related New Zealand Apiaceae

A chemosystematic HPLC-UV and HPLC-MS investigation of New Zealand members of the Apiaceae was performed. Diterpenes were identified and quantified in methanolic extracts from subaerial parts of 28 taxa and 54 samples of Aciphylla, Anisotome, Apium, Gingidia, Lignocarpa, Oreomyrrhis, and Scandia. Six diterpenes (1-2, 4-7) and four polyacetylenes (8-11) were identified. The known compounds were the diterpenes anisotomenoic acid 1, anisotomene-1-ol 2, 16-acetoxyanisotomenoic acid 4 and anisotomene-1,12-diol 5; and the polyacetylenes falcarinol 8, falcarindiol 9, (+)-9(Z),17-octadecadiene-12,14-diyne-1,11,16-triol 10, and (+)-9(Z),17-octadecadiene-12,14-diyne-1,11,16-triol 1-acetate 11. New irregular diterpenes 13,14-dihydroanisotom-12E-ene-1,14-diol 6 and 14-methoxy-13,14-dihydroanisotom-12E-ene-1-ol 7 were isolated from A. haastii. Isomers of the new semi-synthetic diterpene 16-hydroxyanisotomenoic acid 3 were detected in extracts of Anisitone flexuosa. Structure elucidation was performed by HR mass spectrometry and 1D and 2D NMR spectroscopy. In crude extracts, compounds were identified by their HPLC retention times and their on-line HPLC-UV and MS spectra. Anisotomene diterpenes occurred in eight out of 16 species of the genus Anisotome, but were not detected in any of the other genera. In contrast, polyacetylenes were present in all the genera investigated.     

Clerodane and labdane diterpenoids from Nuxia sphaerocephala

Seven diterpenoids including four clerodane and three labdane derivatives, (13S)-ent-7beta-hydroxy-3-cleroden-15-oic acid (1), ent-7beta-hydroxy-2-oxo-3-cleroden-15-oic acid (2), ent-2,7-dioxo-3-clero-den-15-oic acid (3), ent-18-(E)-caffeoyloxy-7beta-hydroxy-3-cleroden-15-oic acid (4) (13S)-ent-18-(E)-coumaroyloxy-8(17)-labden-15-oic acid (5), ent-18-(E)-caffeoyloxy-8(17)-labden-15-oic acid (6), ent-15-(E)-caffeoyloxy-8(17)-labden-18-oic acid (7), have been isolated from an ethyl acetate extract of the leaves of Nuxia sphaerocephala, together with 17 known compounds. 3-Oxolup-20(29)-en-30-al (3-oxolupenal) (8) and 3beta-hydroxylup-20(29)-en-30-al (3beta-hydroxy-lupenal) (9) showed the best inhibitory activity against Plasmodium falciparum with the IC(50) values between 1.55 and 4.67 microg/ml in vitro, respectively. The structure and the relative stereochemistry of the compounds were established on the basis of their spectroscopic properties. The absolute configuration at C-13 of 1 and 5 was determined by the PGME amide procedure.     

Fatty acids as natural specific inhibitors of the proto-oncogenic protein Shp2

Src homology-2 domain-containing protein tyrosine phosphatase (Shp2), a novel proto-oncogenic protein, is an important target in cancer therapy research. Approximately 2000 plant extracts were screened to find its natural specific inhibitors, with the ethyl acetate (EtOAc) active extract of the root of Angelica dahurica showing considerable inhibitory effects (IC(50)=21.6 mg/L). Bioguided isolation of EtOAc extract led to 13 compounds, including 10 fatty acids and derivatives. All these compounds were isolated from the plant for the first time. The inhibitory effects of these compounds on the enzyme activities of Shp2, VH1-related human protein (VHR), and hematopoietic protein tyrosine phosphatase (HePTP) were investigated. 8Z,11Z-Feptadecadienoic acid (4), 14Z,17Z-tricosadienoic acid (5), caffeic acid (9), and 2-hydroxy-3-[(1-oxododecyl) oxy]propyl-β-d-glucopyranoside (11) showed considerable selective inhibition of Shp2 activity. After treatment of HepG2 cells with the compounds, only compound 5, a polyunsaturated fatty acid, strongly induced poly (ADP-ribose) polymerase (PARP) cleavage in a dose- and time-dependent manner and increased the activities of caspase-3, caspase-8, and caspase-9 at 100 μM. Compound 5 also inhibited colony formation of HepG2 cells in a dose-dependent manner. Thus, this study reported fatty acids as specific Shp2 inhibitors and provided the molecular basis of one active compound as novel potential anticancer drug.     

A Study on Pollen Morphology of Potamogeton,Zannichellia and Triglochin from China

The pollen morphology of 19 species in the genera Potamogeton, Zannichellia and Triglochin from China was examined under light and scanning electron microscopes. 1. Pollen characteristics (1) Potamogeton L. (Plate 1, 2:1-8) Pollen grains spheroidal, subspheroidal, rarely oblate or ovoid, (17-35)24.41×27.76(18-45)μm in size; anaperturate; exine 1-2μm thick, 2layered or obscure; crass-reticulate, reticulate or finely-reticulate under LM, distinctly reticulate under SEM; muri uniform or not uniform, smooth or granular, rarely with processes; bacula thicker or thinner at the intersection of muri. (2) Zannichellia L. (Plate 2:9) Pollen grains spheroidal, ,(20-26)23.1×24.15(21-27) μm in size; anaperturate; exine 1 μm thick, stratification obscure; nearly reticulate under LM, shallowly reticulate under SEM; luminae shallow, large and irregular, muri very thin and not uniform; bacula absent. (3) Triglochin L. (Plate 2:10-11) Pollen grains spheroidal or subspheroidal; (20-30)23.65×23.7(20-30) μm in size; anaperturate; exine about 1μm thick, stratification obscure, finely reticulate under LM, distinctly reticulate under SEM; luminae rather large or minute; muri uniform, with 1-2 lines of granules, bacula present or absent. 2. Pollen types of Potamogeton L. (1) Thin muri--thick bacula: Potamogeton pectinatus, P. intramongolicus, P. filiformis, P. pamiricus; (2) Uniform muri and bacula: 1) Large pollen subtype: Potamogeton crespus; 2) Medium-sized pollen subtype: Potamogeton heterophyllus, P. perfoliatus, P. distinctus, P. malaianus; 3) Minute pollen subtype: Potamogeton oxyphyllus, P. obtusifolius, P. lucens, P. cristatus, P. gramineus, P. octandrus, P. pusillus     

Abietane diterpenes from the cones of Cedrus atlantica

Five new abietanes, three of them isolated as the corresponding acetate derivatives, i.e., 9alpha,13alpha-epidioxiabiet-8(14)-en-18-ol, 7alpha,18-diacetoxy, 9beta,13beta-epidioxiabiet-8(14)-ene, 7alpha,18-diacetoxyabiet-8(14)-en-13beta-ol, 7alpha,18-diacetoxy-13beta-methoxyabiet-8(14)-ene, and 13beta-hydroxyabiet-8(14)-en-7-one, were isolated from the neutral part of the hexane extract of the cones of Cedrus atlantica collected in Middle Atlas, Morocco. The structures of these compounds were established by spectroscopic techniques, including 2D NMR spectra, and in the case of 1, by chemical correlation. The cytotoxicity of these abietane diterpenoids was tested against five cell lines.     

Diterpenoids from Calceolaria inamoena

Four 9-epi-ent-labdanes were isolated from the aerial parts of Calceolaria inamoena. Their structures, 2beta-hydroxy-9-epi-ent-labda8(17)-13(E)dien-15-oic acid, 2beta-hydroxy-9-epi-ent-labda8(17)-13(Z)dien-15-oic acid, 2beta-hydroxy-9-epi-ent-labda8(17)-13(E)dien-15-al and 2beta-hydroxy-9-epi-ent-labda-8(17)-13(Z)dien-15-al, were established by spectroscopic methods including by analysis of 2 dimensional heteronuclear correlation experiments 1H/13C (normal and long range), and NOE and gs-sel-1D-NOESY and TOCSY of their methyl ester or acetyl derivatives.     

Sesquiterpenes from the east African sandalwood Osyris tenuifolia

The essential oil of the east African sandalwood Osyris tenuifolia was investigated by chromatographic and spectroscopic methods. Beside several already known sesquiterpenes four new compounds could be isolated by preparative gas chromatography and their structures investigated by mass spectroscopy and NMR techniques. Two of the new compounds--tenuifolene (17) and ar-tenuifolene (15)--show a new sesquiterpene backbone. 2,(7Z,10Z)-Bisabolatrien-13-ol (23) and the cyclic ether lanceoloxide (21) belong to the bisabolanes.     

Genetic structure and morphological variation of British populations of the hybrid Potamogeton x salicifolius

Potamogeton x salicifolius Wolfg. is one of the three most frequently recorded Potamogeton hybrids in the British Isles and Europe. It is thought to be the hybrid between P. lucens and P. perfoliatus. Its scattered distribution suggests that it has arisen several times in Britain. Most British populations of P. x salicifolius can be identified by their morphological characteristics, which are intermediate between those of the putative parents P. lucens and P. perfoliatus . However, the population at the Ouse Washes, Cambridgeshire, differs from other populations in its greater similarity to P . lucens . A genetic study of eight British populations, using six isozyme systems, revealed that most populations consist of a single multi-enzyme phenotype. This suggests that they were the result of a single hybridization event and are therefore maintained through vegetative reproduction. By contrast, the Ouse Washes population consists of three multi-enzyme phenotypes. This variation is likely to have resulted from multiple hybridization events, although we cannot exclude the possibility that the plants are partially fertile. The isozyme systems studied were unable to identify P. lucens and P. perfoliatus unambiguously, and consequently did not provide evidence for their putative parentage of P. x salicifolius. However, at a local level the banding patterns of the hybrids were generally consistent with the local multi-enzyme phenotypes of these putative parents.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 99–111.     

Diterpenoids and triterpenoids from Euphorbia guyoniana

Two new compounds with tigliane and cycloartane skeletons: 4,12-dideoxy(4alpha)phorbol-13-hexadecanoate (1) and 24-methylenecycloartane-3,28-diol (2), respectively, in addition of four known diterpenoids and 13 triterpenoids: 3-benzoyloxy-5,15-diacetoxy-9,14-dioxojatropha-6(17),11-diene (4), ent-abieta-8(14),13(15)-dien-16,12-olide (5), ent-8alpha,14alpha-epoxyabieta-11,13(15)-dien-16,12-olide (6), ent-3-hydroxyatis-16(17)-ene-2,14-dione (7), 3beta-hydroxytaraxer-14-en-28-oic acid (8), beta-sitosteryl-3beta-glucopyranoside-6'-O-palmitate (9), multiflorenyl acetate (10), multiflorenyl palmitate (11), peplusol (12), 24-methylenecycloartanol (3), lanosterol (13), euferol (14), butyrospermol (15), cycloartenol (16), obtusifoliol (17), cycloeucalenol (18) and beta-sitosterol (19), were isolated from the roots of Euphorbia guyoniana. Their structures were established on the basis of physical and spectroscopic analysis, including 1D and 2D homo- and heteronuclear NMR experiments (COSY, HSQC, HMBC and NOESY) and by comparison with the literature data.     

Three labdane diterpenoids from Aframomum sceptrum (Zingiberaceae)

Three labdane diterpenoids, 8beta,17-epoxy-3beta,7beta-dihydroxy-12(E)-labden-16,15-olide (1), methyl 8beta,17-epoxy-3beta,7beta,15-trihydroxy-12(E)-labden-16-oate (2) and 3beta,7beta,8beta,12zeta,17-pentahydroxylabdan-16,15-olide (3) have been isolated from the seeds of Afromomum sceptrum K. Schum (Zingiberaceae) and their structures assigned on the basis of their spectroscopic properties. Nerolidol, and the known flavonoids 3-acetoxy-4',5,7-trihydroxyflavanone, and 3,4',5,7-tetrahydroxyflavanone were also obtained.     

Diterpene constituents of leaves from Juniperus brevifolia

The dichloromethane extract from leaves of Juniperus brevifolia, through chromatographic fractionations yield six compounds: 3beta-hydroxy-abieta-8,11,13-trien-7-one, 18-hydroxy-sandaracopimara-8(14),15-dien-7-one, sandaracopimara-8(14),15-dien-18-yl formate; and the first examples of sandaracopimaranes and abieta-8,11,13-triene diterpenoids with a large aliphatic chain on C-18, abieta-8,11,13-trien-18-yl hexadecanoate, 7-oxoabieta-8,11,13-trien-18-yl hexadecanoate, sandaracopimara-8(14),15-dien-18-yl hexadecanoate. Moreover fifteen known compounds were also isolated, some of them for the first time identified on Juniperus genus. The compound abieta-8,11,13-trien-18-yl formate is reported for the first time as a natural product. All the structures were established by spectroscopic methods. 2D NMR techniques have allowed the revision of certain previously reported (13)C NMR assignments. Studies on the isolated new compounds showed those possessing a diterpenol ester of a long-chain fatty acid present lipophilicity very distinct from other diterpenoid compounds.     

Antialgal furano-diterpenes from Potamogeton natans L

Six furano-ent-labdanes, 19-acetoxy-15,16-epoxy-8(17),13(16),14-ent-labdatrien-20-al, 15,16-epoxy-12-oxo-8(17),13(16),14-ent-labdatrien-20,19-olide, 12(S)-hydroxy-15,16-epoxy-8(17),13(16),14-ent-labdatrien-20,19-olide, 10alpha,19-dihydroxy-15,16-epoxy-8(17),13(16),14-nor-ent-labdatriene, 19,20-dihydroxy-15,16-epoxy-8(17),13(16),14-ent-labdatriene, 15,16-epoxy-12-oxo-8(17),13(16),14-ent-labdatrien-19,20-olide, were isolated, together with the known potamogetonin, from the aquatic plant Potamogeton natans. Their structures were determined on the basis of their chemical and spectral data. The compounds showed in vitro phytotoxicity against Raphidocelis subcapitata, a microalga used in aquatic tests.     

Cytotoxic clerodane diterpenes from Glossocarya calcicola

Three clerodane diterpenes were isolated and identified from leaf extract of Glossocarya calcicola. Compound has been characterised as (rel)-10betaH-trans-12xi-(2-methylbut-2(E)-enoyl)-1beta-(isobutanoyl)-6alpha,13xi-dihydroxyclerodan-4(20),8(18)-dien-7,15-dione-15,16-oxide, to which we have assigned the trivial name calcicolin-A. The other two compounds had the same skeletal structure and C-12 substituent but in compound, the C-1 esterifying group becomes 2-methylbut-2(E)-enoic acid and in it becomes 2-methylbutanoic acid. Although anti-insect activity was not observed for G. calcicola, cytotoxicity against insect and human carcinoma cell lines was detected.     

Polar lipid and fatty acid profiles – Re-vitalizing old approaches as a modern tool for the classification of mycoplasmas?

A set of 20 Mollicutes strains representing different lines of descent, including the type species of the genus Mycoplasma, Mycoplasma mycoides, Acholeplasma laidlawii and a strain of Mesoplasma, were subjected to polar lipid and fatty acid analyses in order to evaluate their suitability for classification purposes within members of this group. Complex polar lipid and fatty acid profiles were detected for each examined strain. All strains contained the polar lipids phosphocholine-6'-alpha-glucopyranosyl-(1'-3)-1, 2-diacyl-glycerol (MfGL-I), 1-O-alkyl/alkenyl-2-O-acyl-glycero-3-phosphocholine (MfEL), sphingomyelin (SphM), 1-O-alkyl/alkenyl-glycero-3-phosphocholine (lysoMfEL), the unknown aminophospholipid APL1 and the cholesterol Chol2. A total of 19 strains revealed the presence of phosphatidylethanolamine (PE) and/or phosphatidylglycerol (PG), and the presence of diphosphatidylglycerol (DPG) was detected in 13 strains. The unknown aminolipid AL1 was found in the extracts of 17 strains. Unbranched saturated and unsaturated compounds predominated in the fatty acid profiles. Major fatty acids were usually C16:0, C18:0, C18:1 omega9c and 'Summed feature 5' (C18:2 omega6, 9c/C18:0 anteiso). Our results demonstrated that members of the M. mycoides cluster showed rather homogenous polar lipid and fatty acid profiles. In contrast, each of the other strains was characterized by a unique polar lipid profile and significant quantitative differences in the presence of certain fatty acids. These results indicate that analyses of both polar lipid and fatty acid profiles could be a useful tool for classification of mycoplasmas.     

Microbiological transformation of two labdane diterpenes, the main constituents of Madia species, by two fungi

Microbial transformation of 13R,14R,15-trihydroxylabd-7-ene (5) and 13R,14R,15-trihydroxylabd-8(17)-ene (6) by the fungus Debaryomyces hansenii gave 1 (13R,14R,15-trihydroxy-6-oxolabd-8-ene) and 3 (7alpha,13R,14R,15-tetrahydroxy-labd-8(17)-ene), respectively. While, microbial transformation of 5 by Aspergillus niger afforded 2 (3beta,13R,14R,15-tetrahydroxy-labd-7-ene), and 13R,14R,15-trihydroxylabd-8,17-ene (6) gave 3 and 4 (3R,14R,15-3-oxotetrahydroxy-labd-7-ene). The structures of the new compounds, 1 and 2, were assigned by 1D and 2D high-field NMR spectroscopic methods. Antimicrobial activity of these compounds were tested and their MIC were determined.     

Polyhydroxylated steroids from the soft coral Sinularia dissecta

A repeated silica gel column chromatography followed by HPLC purification on the methanol extract of marine soft coral Sinularia dissecta, resulted in the isolation of fifteen polyhydroxylated steroids (1-15), involving six new C-18 functionalized steroids, 3beta-acetoxy-1alpha,11alpha-dihydroxygorgost-5-en-18-oic acid (1), gorgost-5-en-1alpha,3beta,11alpha,18-tetrol (2), 18-acetoxy-1alpha,3beta,11alpha-trihydroxygorgost-5-ene (3), 24(S)-3beta-acetoxy-1alpha, 11alpha-dihydroxyergost-5-en-18-oic acid (4), 24(S)-ergost-5-en-1alpha,3beta,11alpha,18-tetrol (5), and dissectolide (6). The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, (1)H and (13)C NMR, HMQC, HMBC, and NOESY) analysis. Compound 6 was found as an unusual sterol bearing a lactone functionality.