Havardic acids A-F and havardiol,labdane diterpenoids from Grindelia havardii

Seven new labdane diterpenoids, designated as havardic acids A-F (as methyl esters) and havardiol, have been obtained from the dichloromethane extract of the aerial parts of Grindelia havardii, and their structures have been deduced on the basis of NMR, MS and IR data. Havardic acid E has lost carbons-14 and -15, whereas havardic acid F and havardiol have lost carbon-17.     

A New Depigmenting‐Antifungal Methylated Grindelane from Grindelia chiloensis

The new methylated grindelane diterpenoid, 7β ‐hydroxy‐8(17)‐dehydrogrindelic acid ( 1b ), together with the known 7α ‐hydroxy‐8(17)‐dehydrogrindelic acid ( 2a ), 6‐oxogrindelic acid ( 3a ), 4β ‐hydroxy‐6‐oxo‐19‐norgrindelic ( 4a ), 19‐hydroxygrindelic acid ( 5a ), 18‐hydroxygrindelic acid ( 6a ), 4α ‐carboxygrindelic acid ( 7a ), 17‐hydroxygrindelic acid ( 8a ), 6α ‐hydroxygrindelic acid ( 9a ), 8,17‐bisnor‐8‐oxagrindelic acid ( 10a ), 7α ,8α ‐epoxygrindelic acid ( 11a ), and strictanonic acid ( 12a ) as methyl esters were obtained from an Argentine collection of Grindelia chiloensis (Cornel .) Cabrera . Their structures and relative configurations were established on the basis of spectroscopic analysis. CHC l₃ extract from the aerial parts and their pure compounds were evaluated for their antifungal and depigmenting effects. Methyl ester derivative of 10a ( 10b ) exhibited a remarkable mycelial growth inhibition against Botritis cinerea with an IC ₅₀ of 13.5 μg ml^?1. While the new grindelane 1b exerted a clear color reduction of the yellow‐orange pigment developed by Fusarium oxysporum against UV ‐induced damage.     

Seasonal variation in resource allocation of extractable compounds in Asclepias,Chrysothamnus and Grindelia

The yields of whole plant hexane and methanol soluble extractables from Asclepias speciosa; Chrysothamnus itnauseosus subsp, consimilis and Grindelia squarrosa were examined throughout the growing season. The yields of non-polar extractables remained relatively constant during the growing season with increases in late summer or early fall according to the species. Each of the three taxa showed a similar pattern with the methanol soluble fraction reaching a maximum in June. However, a second maximum was observed in Asclepias and Grindelia in August. Protein content was examined in Asclepias and Grindelia and was found to decline throughout the growing season. Individual components of the hexane extract of Asclepias were examined and several components were found to vary seasonally. Principal components analysis of the nonpolar components revealed that the components with high intercorrelations were members of five chemical biosynthetic classes: alkanes, fatty acids, pentacyclic triterpenoids and tetracyclic sterols. Canonical variate analysis grouped the samples by date of sample from May to September-October.     

Rare,seven-membered cyclic ether labdane diterpenoid from Dodonaea polyandra

Previous phytochemical studies on the leaf resin of dioecious plant species Dodonaea polyandra have identified the presence of furanoclerodane diterpenoids. As part of ongoing research on this species the chemical profile of an individual plant displaying male flowers was investigated. Repeated chromatographic separation of a resinous extract from the leaves of the plant yielded three labdane diterpenoids, 13,17-epoxy-13-methyl-15-oxo-labda-7-ene (1), 17-hydroxy-13-methyl-labda-7,13Z-diene-15-oic acid (2) and 13-methyl-17-oxo-labda-7,13Z-diene-15-oic acid (3) and a fourth known labdane diterpenoid (4) reported as being isolated from a natural source for the first time. Structural elucidation was carried out using conventional 1D and 2D NMR and mass spectrometry together with other complementary techniques (UV and IR). The leaf extract from this individual of D. polyandra with male flowers present displays a marked difference in the chemical composition of diterpenoids compared to previously studied extracts from the leaves of this species.     

Diterpenes related to grindelic acid and further constituents from Grindelia species

The aerial parts of Grindelia stricta afforded in addition to known compounds 21 diterpenes, all closely related to grindelic acid. The aerial part     

A new ent-kaur-16-en-19-oic acid from the aerial parts of Inula bifrons

The phytochemical study of the chloroform extract of the aerial parts of Inula bifrons (L.) L. led to the isolation of one new ent-kaurane diterpenes acid along with twelve known compounds (two ent-kaurane diterpenoids, an eudesmane acid, five sesquiterpene lactones, three triterpenoids and β-sitosterol). All known compounds are found for the first time in I. bifrons. Their structures were elucidated by using spectral methods (NMR, HRESIMS and IR). The distribution of these compounds in the genus Inula and their chemotaxonomic significance is discussed.     

Diterpenoids from Pinus massoniana resin and their cytotoxicity against A431 and A549 cells

Five diterpenoids and 14 known diterpenoids were isolated from the petroleum ether extract of Pinus massoniana resin. Their structures were elucidated by spectroscopic data interpretation. The cytotoxic activities of these compounds were evaluated using the MTT method. The results showed that three of the less polar diterpenoids had strong cytotoxicity against A431 and A549 cancer cells, whereas those of high polarity had none.     

Toxicity of daphnane-type diterpenoids from Genkwa Flos and their pharmacokinetic profile in rat

Daphnane-type diterpenoids (DDs) are the main types of plant diterpene orthoesters known and have remarkable biological activities. However, the in vivo toxicity and pharmacokinetic profile of DDs remains unkonwn. The aim of this study was to investigate the toxicity and pharmacokinetic profile of DDs from Genkwa Flos (Thymelaeaceae). The toxicity of diterpenoids was evaluated after oral administration of total diterpenoids extract from Genkwa Flos to rats, and the blood concentration of diterpenoids was analyzed by ultra performance liquid chromatography tandem triple-quadrupole mass spectrometry (UPLC–TQ-MS). The diterpenoids were confirmed to be the toxic components of Genkwa Flos. The pharmacokinetic profile of these diterpenoids was quite different due to their different structures. Although the contents of yuanhuafine and yuanhuapine were low in the extract, the blood concentrations were extremely high. In contrary, the contents of genkwanine F and Wikstroemia factor M₁ in the extract were much higher, but they could not be detected in the blood. This result implied that yuanhuafine and yuanhuapine but not genkwanine F and Wikstroemia factor M₁ were the potentail toxic components of Genkwa Flos in vivo. This paper shows for the first time the toxicity of diterpenoids from Genkwa Flos was correlated with their blood concentration and when DDs were used for medicinal purposes, their contents in herb as well as their blood concentrations should be considered.     

Chemical study of the seeds of Erythrophleum ivorense A. Chev. (Fabaceae)

The Chemical study of methanolic extract of the seeds from Erythrophleum ivorense led to the isolation of one original cassane diterpenoid (1) along with six known cassane diterpenoids (2–7). In addition, the known compounds (2–7) are isolated for the first time in E. ivorense. Their structures were established according to their spectral data (NMR, HRESIMS, IR). This result confirms that cassane-type diterpenoids are one of the major constituents of Erythrophleum species. The identification of these compounds and their chemotaxonomic significance is discussed.     

Cassane diterpenoids from stem bark of Erythrophleum suaveolens [(Guill. et Perr.), Brenan]

Phytochemical investigation of the stem bark of Erythrophleum suaveolens yielded four new cassane diterpenoids; 6α-hydroxy-cassamic acid, methyl ester, 4β-carbomethoxy-14-methyltotarol, 6α-hydroxy-nor-cassamine, and 8,9-dehydro-nor-cassamine, along with four known cassane diterpenoids. All structures were elucidated on the basis of one- and two-dimensional NMR, HRMS and ESIMS analysis.     

Grindelane diterpenoids from Grindelia campórum and Chrysothamnus paniculatus

The structures of nine grindelic acid related diterpenes isolated as methyl esters from Grindelia camporum and Chrysothamnus paniculatus, were elucidated based on their spectral properties.     

Germacrane derivatives from Santolina chamaecyparissus

The aerial parts of Santolina chamaecyparissus subsp. squarrosa yieleded five new germacrane derivatives and a known eudesmane dialcohol.     

New alkamide and ent-kaurane diterpenoid derivatives from Senecio erechtitoides (Asteraceae)

Fractionation of a MeOH/CH₂Cl₂ (1/1) extract of the aerial parts of Senecio erechtitoides led to the isolation of six compounds including the hitherto unknown N-phenethylamide derivative named N-(p-hydroxyphenethyl)pentacosanamide (1), and a kauranoid derivative named derivative named ent-7-oxo-16α,17-dihydroxykauran-19-oic acid (2), as well as four known compounds, ent-Kaur-16-en-19-oic acid (3), ent-7β-hydroxykaur-16-en-19-oic acid (4), ent-7-oxokaur-16-en-19-oic acid (5), steppogenin 4′-O-β-d-glucoside (6). Their structures and relative configurations were elucidated on the basis of spectroscopic methods, chemical reactions, and comparison with previously known analogs. All isolates were evaluated for their antimicrobial activity and only diterpenoids were found to possess a potent inhibitor effect against the range of microorganism.     

Allelopathic potential of Artemisia frigida and successional changes of plant communities in the northern China steppe

In the northern China steppe, overgrazing has decreased the abundance of many species that were originally dominant, but increased the abundance of Artemisia frigida. We aimed to determine whether the adaptive and competitive abilities of A. frigida are associated with allelopathy. Soil nutrient characteristics could not explain the poor growth of the originally dominant species. Volatile compounds released from A. frigida leaves and aqueous extracts (0.025, 0.05, 0.075, 0.10, and 0.15 g ml^?1) from A. frigida leaves and roots and from soil under A. frigida inhibited seed germination and seedling growth of three dominant species (Leymus chinensis, Stipa krylovii, and Cleistogenes squarrosa). Allelopathic activity varied according to extract concentration, test species, and extract source. Germination was most strongly inhibited in S. krylovii, followed by L. chinensis and then C. squarrosa. Seedling growth was most strongly inhibited in L. chinensis, followed by S. krylovii and then C. squarrosa. Gas chromatography–mass spectrometry analyses of the leaf volatiles identified 27 compounds, primarily monoterpene or sesquiterpene compounds and their oxygen-containing derivatives, such as eucalyptol, beta.-myrcene, 1,6-octadien-3-ol,3,7-dimethyl, 3-carene, bicyclo[2.2.1]heptan-2-one,1,7,7-trimethyl-,(1R), cis-sabinenehydrate, camphene, and alpha-Pinene. These findings suggest that allelochemicals from A. frigida can modify the surrounding micro-habitat. The responses of target plants to allelopathy of A. frigida may be one reason for changes in plant community succession in the northern China steppe.     

Two new diterpenoids from the roots of Pygmacopremna herbacea

Two new diterpenoids, neobharangi-δ-lactone (1) and bharangi quinone (2) along with two known compounds neobharangin (3) and bharangin (4) were isolated from the ethyl acetate extract of root nodules of Pygmacopremna herbacea. The structures of the new compounds were established by 1D and 2D NMR spectroscopic data.     

Diterpenoids from Salvia oxyodon and Salvia lavandulifolia

Three new diterpenoids have been detected in Salvia oxyodon and identified as 3β-hydroxy-dehydroabietic acid, 3β-acetoxy-abieta-8(14)-en-18-oic acid 9α,13α-endoperoxide and 3β-hydroxy-abieta-8(14)-en-18-oic acid 9α,13α-endoperoxide. Salvia lavandulifolia yielded two known compounds ursolic acid and galdosol.     

Clerodane and 19-norclerodane diterpenoids from the tubers of Dioscorea antaly

Two clerodane diterpenoids, antadiosbulbins A and B and two 19-norclerodane diterpenes, 8-epidiosbulbins E and G along with the known diosbulbin E as well as nine known phenolics including five phenanthrenes and stilbenes and four flavonoids were isolated from the ethyl acetate soluble part of the methanolic extract of the tubers of Dioscorea antaly, a yam endemic to Madagascar. Structures were determined by analysis of the spectral data, mainly 2D-NMR and mass spectrometry.     

Sesquiterpene lactones and diterpenoids from Helianthus argophyllus

Three germacranolide sesquitepene lactones (argophyllin-A and -B and eupatolide), three diterpenoids (ciliaric acid, (?)-16-α-hydroxy-kaur-11-en-19-oic acid and (?)-16-α-hydroxykaurane) and one flavonoid (nevadensin) were isolated and characterized from a chloroform extract of Helianthus argophyllus. Argophyllin-A and -B are both described here for the first time. Their structures were deduced by ¹H NMR and ¹³C NMR. Argophyllin-A and -B were found to show anti-auxin effects while eupatolide exhibited weak insecticidal activity.     

New natural diterpene acids from Juniperus communis

Three new diterpene acids have been isolated from the leaves of Juniperus communis and their structures, elucidated by spectroscopic methods, were identified as 7-oxo-13-epi- pimara-8,15-dien-18-oic acid, 7α-hydroxysandaracopimaric acid and (14 S)-14,15-dihydroxylabda- 8(17),13(16)-dien-19-oic acid. Biflavonyls, fatty acids and diterpenoids with known structures were also isolated.