New diterpene isocyanides from a sponge

Six new diterpene isocyanides have been isolated from a sponge ($\text{Adocia}$ sp.). Their structures support the biosynthetic suggestion for the formation of diisocyanoadociane reported from the same sponge.     

A new diterpene glycoside from Rabdosia rubescens

A new ent-kaurene beta-D-glucoside was isolated from Rabdosia rubescens, together with the known compounds oridonin, ponicidin, and pedalitin. The structure of new compound was determined, on the basis of spectral data and X-ray crystallographic analysis, to be ent-7 beta,20-epoxy-kaur-16-ene-1 beta,6 alpha,7 alpha,14 alpha,15 alpha-pentanol 1-O-beta-D-glucopyranoside.     

Two new diterpene polyesters from Euphorbia decipiens

Two new myrsinol-type diterpene polyesters 3,5,13,17-tetra-O-acetyl-7-O-benzoyl-15-hydroxymyrsinol (1) and 3,5,13,17-tetra-O-acetyl-7-O-butanoyl-13-hydroxymyrsinol (2), with a tricyclic carbon skeleton have been isolated from Euphorbia decipiens Boiss. & Buhse. The structure elucidation of the isolated compounds was based primarily on HREIMS, EIMS, IR, UV, ID-, and 2D-NMR analyses, including COSY, HMQC, HMBC, and NOESY correlations. Compounds 1 and 2 also showed activity against urease enzyme.     

Two new diterpene alkaloids from Delphinium chrysotrichum

Chemical investigation on the ethanol extract from the whole plants of Delphinium chrysotrichum resulted in the isolation of two new diterpene alkaloids named delphatisine A (1) and delphatisine B (2), respectively. The structures of the new compounds were deduced on the basis of their spectral data (IR, HREIMS, EIMS, 1D, 2D-NMR). This is the first report on the isolation of diterpenoid alkaloids from the D. chrysotrichum.     

Anticandidal pimaradiene diterpene from Phlomis essential oils

In the present study, it was aimed to investigate the phytochemical profile and antimicrobial effects of Phlomis lunariifolia Sm., Phlomis amanica Vierh., Phlomis monocephala P.H. Davis, Phlomis sieheana Rech. fil, Phlomis armeniaca Willd. essential oils collected from Turkey. The Phlomis essential oils were obtained from the aerial parts by hydrodistillation and were subsequently analyzed both by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). Chromatographic separations followed by structure identification of individual compounds of interest from Phlomis essential oils were conducted using 1D and 2D NMR, FT-IR, UV and HRMS techniques. In addition, antimicrobial studies using a microdilution assay and TLC bioautography were applied to the essential oils and the relevant components. The analysis of the essential oils led to the identification of 143 compounds, where an unknown volatile compound was detected as the major compound (22.8% and 12.7%) in the essential oils of P. amanica and P. monocephala, respectively. After chromatographic clean up, the isolation and characterization of this compound resulted in (−)-8(14),15-isopimaradien-11α-ol. The sesquiterpene germacrene-D was identified as the major constituent of P. lunariifolia (7.7%), P. sieheana (16.6%) and P. armeniaca (23.4%) oils. 4-Methoxycarbonyl-7-methyl cyclopenta[c]pyrane – a fulvoiridoid – was obtained by acid hydrolysis from iridoid ipolamiide which was shown to be present in the oils of P. armeniaca (1.4%) and P. sieheana (0.2%). Furthermore, Phlomis essential oils were investigated for their antifungal properties using a TLC bioautographic assay where the diterpene was shown as the active principle against Candida albicans and Candida tropicalis when compared with standard antifungal agents. Minimum inhibitory concentrations against various human pathogenic bacteria (from 125 to >1000 μg/ml), C. albicans and C. tropicalis (62.5–1000 μg/ml), were determined using a microdilution assay. The results obtained from this study suggest that essential oils and their individual compounds thereof may be potential resource and ingredients for pharmaceuticals or cosmetics with antimicrobial activity.     

Additional minor diterpene glycosides from Stevia rebaudiana

From the commercial extract of the leaves of Stevia rebaudiana, two additional new diterpenoid glycosides were isolated and their structures were characterized as 13-[(2-O-beta-glucopyranosyl-3-O-beta-D-xylopyranosyl-beta-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid beta-D-glucopyranosyl ester (1) and 13-[(2-O-beta-D-xylopyranosyl-beta-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid beta-D-glucopyranosyl ester (2) on the basis of extensive spectral data (NMR and MS) and chemical studies.     

A new furanoid diterpene from Caesalpinia pulcherrima

A new cassane-type diterpene isovouacapenol E (1) was isolated from the leaves of Caesalpinia pulcherrima, together with the known compounds caesaldekarin A (3), spathulenol (4), caryophyllene oxide (5), phytol, and sitosterol. The structure of 1 was elucidated by spectral data interpretation.     

A new diterpene glycoside from Stevia rebaudiana

From the commercial extract of the leaves of Stevia rebaudiana, a new diterpene glycoside was isolated besides the known steviol glycosides including stevioside, rebaudiosides A-F, rubusoside and dulcoside A. The new compound was identified as 13-[(2-O-β-D-glucopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-(2-O-α-L-rhamnopyranosyl-β-D-glucopyranosyl) ester (1) on the basis of extensive spectroscopic (NMR and MS) and chemical studies.     

A new casbane diterpene from Euphorbia pekinensis

A new casbane diterpenoid, referred to as pekinenin G, together with one cembrane diterpene and four known casbane diterpenoids were isolated from the roots of Euphorbia pekinensis. Their structures were elucidated on the basis of spectroscopic studies and comparison with related known compounds. The six compounds showed different cytotoxic activities against four human cancer cell lines.     

A new tigliane-type diterpene from Euphorbia dracunculoides Lam

One new tigliane-type diterpene, 4-deoxy-4(β)H-8-hydroperoxyphorbol-12-benzoate-13-isobutyrate (1), together with two known diterpenoids, 3-acetyl-5,8-dibenzoyl-14α-propanoyl-13,17-epoxy-7-myrsinaone diterpene with C9–C10 cyclised to form an additional lactone ring (2), Euphodendriane A (3) have been isolated from the whole plants of Euphorbia dracunculoides Lam. Their structures were elucidated by means of extensive spectroscopic analysis (NMR and HR-ESI-MS) and comparison with data reported in the literature. This is the first isolation of 8-hydroperoxy tigliane diterpene (1) from the genus of Euphorbia. All compounds were evaluated for their antifungal activities.     

Cembranoid diterpenes and a briarane diterpene from corals

Two new cembrane diterpenes (+)-polydactylide (1) and (+)-7alpha,8beta-dihydroxydeepoxysarcophine (2) together with (+)-sarcophine (3) and (+)-sarcophytoxide (4) have been isolated from the soft coral Sinularia polydactyla. The new cembrane diterpene (-)-7beta-hydroxy-8alpha-methoxydeepoxysarcophine (5) has been obtained from the soft coral Sarcophyton trocheliophorum and the known briarane diterpene briaexcavatolide W (6) from the gorgonian coral Briareum sp.The structures were determined primarily by NMR spectroscopy. The assignment of NMR signals was performed by means of (1)H-(1)H COSY, ROESY, HMQC and HMBC experiments.     

Relative stereochemistry of a diterpene from Salvia cinnabarina

The relative stereochemistry of 3,4-secoisopimara-4(18),7,15-triene-3-oic acid, a diterpenoid with antispasmodic, hypotensive and antibacterial activities isolated from Salvia cinnabarina, was determined by an X-ray diffraction analysis of a single crystal of a suitable crystalline derivative.     

Anti-inflammatory sesquiterpenes from Curcuma zedoaria

From the methanolic extract of the rhizome of Curcuma zedoaria, we isolated anti-inflammatory sesquiterpene furanodiene (1) and furanodienone (2) along with new sesquiterpene compound 3 and known eight sesquiterpenes, zederone (4), curzerenone (5), curzeone (6), germacrone (7), 13-hydroxygermacrone (8), dehydrocurdione (9), curcumenone (10), and zedoaronediol (11). Their structures were elucidated on the basis of spectroscopic data. The anti-inflammatory effect of isolated components on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation of mouse ears were examined. Compounds 1 and 2 suppressed the TPA-induced inflammation of mouse ears by 75% and 53%, respectively, at a dose of 1.0 micromol. Their activities are comparable to that of indomethacin, the normally used anti-inflammatory agent.     

Anti-inflammatory metabolites from marine sponges

Marine sponges are a rich source of biologically active secondary metabolites with novel chemical structures. Eighty four anti-inflammatory compounds have been isolated from marine sponges. This is the first comprehensive review presenting the structures and anti-inflammatory activities of marine sponge metabolites. (100 references).     

A new myrsinol-type diterpene polyester from Euphorbia dracunculoides Lam

A new myrsinol-type diterpene polyester, 14-deoxo-3β-O-propinoyl-2α,5α,7β,15β-tetra-O-acetyl-14α-O-benzoyl-myrsinol (1), and its known analogue, 14-deoxo-3β-O-prorionyl-5α,15β-di-O-acetyl-7β-O-nicotinoyl-myrsinol-14β-acetate (2), together with a monoterpenoid, pubinernoid A (3), two indole alkaloids, neoechinulin A (4) and dihydroxyisoechinulin A (5), two benzene derivatives, siringin (6) and (3-methoxyphenyl) acetic acid (7), were isolated from the 70% acetone extract of the aerial parts of Euphorbia dracunculoides Lam. Their structures were elucidated on the basis of spectroscopic evidence and comparison with literature reports. The absolute configuration of 1 was deduced by comparing experimental and calculated ECD spectra. Among them, compounds 4 and 5 were first obtained from the plant source. In addition, the ¹³C NMR data of compound 2 was reported for the first time.     

Demethylenedelpheline — A new diterpene alkaloid from Delphinium corumbosum

Abu Ali Ibn Sina [Avicenna] Tadzhik State Medical Institute, Dushanbe. Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 50–51, January–February, 1989.