Labdane diterpenoids from Halimium viscosum and H. verticilatum

In addition to three known acids, six new diterpenoid acids with a labdane skeleton, were isolated from the acid fraction of Halimium viscosum. Fou     

Preleosibirin,a prefuranic labdane diterpene from ballota nigra subsp. foetida

From the aerial parts of Ballota nigra subsp. foetida a new prefuranic labdane diterpene, preleosibirin, has been isolated. Its structure was established by spectroscopic means and by correlation with the previously known diterpenoid leosibirin.     

Further diterpenoids from Plectranthus ornatus and P. grandidentatus

A new halimane diterpenoid and the previously known labdane rhinocerotinoic acid were isolated from Plectranthus ornatus Codd. In addition, a new monoacetyl derivative of the abietane coleon U was found among the constituents of Plectranthus grandidentatus Gürke. These diterpenes could be significant from both chemotaxonomic and biogenetic points of view.     

The structure of leocardin,two epimers of a diterpenoid from Leonurus cardiaca

From the aerial part of Leonurus cardiaca a new labdane diterpenoid, leocardin, has been isolated and its structure was established by spectroscopic and chemical means. It has been shown to be 8β-acetoxy-9α,13α,15,16-bisepoxy-15-hydroxy-7-oxo-labdan-6β,19-olide present as a C-15 epimeric mixture.     

Galeuterone and pregaleuterone,labdane diterpenoids from Galeopsis reuteri

From the aerial part of Galeopsis reuteri a furanic labdane diterpenoid, galeuterone, and its prefuranic derivative, pregaleuterone, have been isolated. The structures of these substances have been established mainly by spectroscopic means.     

NO inhibitory constituents as potential anti-neuroinflammatory agents for AD from Blumea balsamifera

Our continuous search for new nitric oxide (NO) inhibitory substances as anti-neuroinflammatory agents for AD resulted in the isolation of one new labdane diterpenoid and three new guaiane sesquiterpenoids, as well as ten known compounds from Blumea balsamifera. Their structures were elucidated by NMR spectroscopic data analysis and the time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. The anti-neuroinflammatory effects were examined by inhibiting NO release in LPS-induced murine microglial BV-2 cells. The possible mechanism of NO inhibition of some bioactive compounds was also investigated using molecular docking, which revealed the interactions of bioactive compounds with the iNOS protein.     

New tetranorlabdane diterpenoids from the fruits of Elettaria cardamomum Maton

A pair of new tetranorlabdane diterpenoid epimers, named elettarins A (1) and B (2), together with five known labdane diterpenes (3–7), were isolated from Elettaria cardamomum Maton. The structures of elettarins A and B were established based on spectroscopic data (HRESIMS, 1D/2D NMR), and ECD experimentation. All isolates were evaluated for their inhibitory activities against nitric oxide (NO) production on BV-2 microglia cells.     

Andrographolide Induces Apoptosis in Gastric Cancer Cells through Reactivation of p53 and Inhibition of Mdm-2

Doklady Biochemistry and Biophysics - Andrographolide is a labdane diterpenoid isolated from Andrographis paniculata. The plant extract and andrographolide has long been used in traditional...     

Cuceolatins A–D: New Bioactive Diterpenoids from the Leaves of Cunninghamia lanceolata

Four new diterpenoids named cuceolatins A–D, including three labdane‐type ( 1 – 3 ) and one abietane‐type ( 4 ) as well as three known labdane analogs ( 5 – 7 ), were reported from the leaves of Cunninghamia lanceolata. Structural assignments for these compounds were conducted by analyses of spectroscopic data, and their absolute configurations were determined by time‐dependent density functional theory (TD‐DFT) based electronic circular dichroism (ECD) calculations. Among them, the abietane‐type diterpenoid (11‐hydroxy‐12‐methoxyabieta‐8,11,13‐trien‐3‐one ( 4 )) showed significant cytotoxicity against human MDA‐MB‐231, MCF‐7, and HeLa tumor cell lines with IC₅₀ measurements of 4.3, 2.8 and 4.5 μm , respectively, while the labdane‐type diterpenoids with a 4α‐carboxy group ( 1 – 3 and 5 ) exhibited moderate antibacterial activity towards Bacillus subtilis and Staphylococcus aureus with IC₅₀ values all below 25 μm .     

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.     

Labdane derivatives from hemizonia species

The investigation of three Hemizonia species afforded in addition to known compounds seven new labdane derivatives, all derived from labd-13-en-15-ol. The absolute configuration of these diterpenes was determined by degradation of the triol by periodate cleavage, which afforded a known norditerpene ketone. From H. fitchii two new chromene esters and the cis-isomer of a known coumarate were isolated. H. congesta afforded in addition to labdane derivatives a hydroxycubebol.     

Labdane Diterpenoids from Coleus forskohlii （Willd.） Briq.

in order to investigate the active substances of Coleus forskohlii（Wiiid.） Brlq., a new labdane dlterpenold, 12- hydroxy-8,13E-labdadlen-15.olc acid, together with two 8,13-epoxylabd-14-ene-11-one dlterpenolds, 6-acetyl-1- deoxyforskolln and 6-acetyl-1,9-dldeoxyforskolln, was Isolated on the basis of various chromatographic technlques and spectroscopic methods.     

Semiatrin,a neo-clerodane diterpenoid from Salvia semiatratha

From the aerial part of Salvia semiatratha, a known diterpenoid and a new neo-clerodane diterpenoid, semiatrin, were isolated. The structure of the new diterpenoid was established mainly by spectroscopic means.     

New labdane diterpenes from Araucaria cooki

Eight new and seven known labdane diterpenes were identified in the oleoresin of Araucaria cooki.     

New diterpenes from Araucaria cunninghami

Eleven labdane diterpenes, nine of which are new compounds, were identified in the oleoresin of Araucaria cunninghami.     

Labdane diterpenes from Brickellia glomerata

The leaves of B. glomerata afforded three new labdane diterpenes. Their structures and stereochemistry were established by spectroscopic methods and chemical transformations.     

A novel Ca2+-signal transduction inhibitor,kujigamberol C,isolated from Kuji amber

ABSTRACT

A novel labdane type diterpenoid, 15-nor-8-labden-13-ol, named kujigamberol C, was isolated from Kuji amber using a modified isolation method to increase the yield of biologically active compounds. The structure was determined using HREIMS, 1D and 2D NMR. Kujigamberol C showed growth-restoring activity against mutant yeast via Ca²⁺-signal transduction.     

Ent-labdanes from austrobrickellia patens

The aerial parts of Austrobrickellia patens afforded five new labdane derivatives. In addition a caryophyllenic acid and several known compounds were isolated.     

Rearranged labdane diterpenoids from Galeopsis angustifolia

From the aerial part of Galeopsis angustifolia collected in Spain, a labdane and three rearranged labdane diterpenoids have been isolated. The structures of these new substances have been established by chemical and spectroscopic means and by correlation with known compounds. A sample of the same species collected in Italy and other species of Galeopsis showed some remarkable chemical differences. The taxonomic significance of these results is discussed briefly.     

Five new labdane diterpene oxides from Eupatorium jhanii

Five new labdane diterpene oxides jhanol, jhanidiol, jhanol acetate, jhanidiol-18-monoacetate and jhanidiol diacetate were isolated from the aerial parts of Eupatorium jhanii.