Cytotoxic and apoptosis-inducing ent-kaurane-type diterpenoids from the Japanese liverwort Jungermannia truncata NEES

Five new ent-kaurane-type diterpenoids and a new gymnomitrane (=barbatane)-type sesquiterpenoid have been isolated from the Japanese liverwort Jungermannia truncata NEES, together with twelve previously known ent-kaurane-type diterpenoids. The structures of the new compounds were elucidated by two-dimensional (2D) NMR experiments and chemical reaction. Some of the isolated compounds showed cytotoxicity against human leukemia cell lines and induced apoptosis.     

Two new icetexane diterpenoids from Salvia przewalskii

Two new icetexane diterpenoids, przewalskin C, D (1, 2), together with sixteen known diterpenoids, were isolated from Salvia przewalskii. Eight of known ones (compounds 3, 12-18) were reported firstly from this plant. To the best of our knowledge, it's the first report of icetexane diterpenoids from this plant. The identification and structural elucidation of these compounds were based on 1D- and 2D-NMR spectral data analysis.     

Terpenoids from the liverwort Chandonanthus hirtellus

A new bicyclogermacrane sesquiterpenoid, two new cembrane diterpenoids and five new dolabellane diterpenoids, along with known terpenoids, have been isolated from the Malaysian liverwort Chandonanthus hirtellus. The structures of the new compounds were established by spectroscopic and chemical methods in addition to X-ray crystallographic studies.     

Tricyclic diterpenoids of the dolastane ring system from the marine alga dictyota divaricata

Four new oxygenated tricyclic diterpenoids have been isolated from the Caribbean brown alga Dictyota divaricata. The structures of these new compounds were secured by an X-ray analysis of a convenient diol derivative, followed by interconversion where possible. The new diterpenoids belong to the dolastane group first isolated from the herbivorous mollusc Dolabella auricularia and their isolation here indicates that the sea hare most likely derived these compounds from brown seaweeds of the family Dictyotaceae.     

Abietane Diterpenoids Isolated from Clerodendrum bracteatum and Their Antioxidant and Cytotoxic Activities

Two new abietane diterpenoids (1,2), along with five known diterpenoids (3–7), were first isolated and purified from the stems of Clerodendrum bracteatum. The structures of the new compounds were established by extensive analysis of mass spectrometric and 1-D, 2-D NMR spectroscopic data. Their antioxidant activities were determined on DPPH radical scavenging and ABTS. The in vitro cytotoxic activities of the compounds were evaluated against the HL-60 and A549 cell lines by the MTT method.     

Secoatisane‐ and Isopimarane‐Type Diterpenoids from the Chinese Mangrove Excoecaria agallocha L.

Phytochemical investigations of the stems and leaves of the Chinese mangrove Excoecaria agallocha L. yielded one new secoatisane‐type diterpenoid, agallochaol C ( 1 ), three new isopimarane‐type diterpenoids, agallochaols D–F ( 2 – 4 ), along with four known diterpenoids 5 – 8 . The structures of new compounds 1 – 4 were determined on the basis of spectroscopic‐data interpretation and chemical evidence.     

Terpenoids with potent antimycobacterial activity against Mycobacterium tuberculosis from Trigonostemon reidioides roots

Phytochemical investigation of Trigonostemon reidioides roots led to the isolation of fourteen compounds. These included six new diterpenoids, trigonoreidons A?F (1?6), together with eight known diterpenoids 7?14. The structures of the new compounds were elucidated by spectroscopic techniques and the absolute configuration at the asymmetric carbon was determined by the modified Mosher's method. The structure of trigonoreidon B (2) was confirmed by X-ray crystallographic analysis. The known compounds were identified by comparison of the spectroscopic and physical data with those of reported values. The isolated compounds were evaluated for antimycobacterial activity against Mycobacterium tuberculosis. Among the compounds that exhibited antimycobacterial activity, the diterpenoids rediocide C (12) and rediocide G (14) were the most active compounds, with the MIC value of 3.84 μM.     

Three New Diterpenoids from Euphorbia sororia L.

Three new diterpenoids with jatrophane‐type skeleton, sororianolides A–C ( 1 – 3 , resp.), were isolated from Euphorbia sororia. The identification and structure elucidation of these compounds were based on 1D‐ and 2D‐NMR‐spectral data analysis. It was the first time to isolate diterpenoids in this species.     

A new diterpenoid glucoside and two new diterpenoids from the fruit of Vitex agnus-castus

A new labdane-type diterpenoid glucoside and two new labdane-type diterpenoids were isolated from the fruit (chasteberry) of Vitex agnus-castus L. (Verbenaceae) along with 14 known compounds comprising seven labdane-type diterpenoids, one halimane-type diterpenoid, two oleanane-type triterpenoids, two ursane-type triterpenoids, one aromadendrane-type sesquiterpenoid, and one flavonoid. Their structures were characterized on the basis of spectroscopic data as well as chemical evidence. Furthermore, the antioxidative activities of the flavonoid were evaluated using five different analyses.     

Two New Abietane Diterpenoids from the Stems of Clerodendrum kaichianum P. S. Hsu

Two new abietane diterpenoids, named 17‐hydroxyteuvincenone G ( 1 ) and 17‐hydroxyteuvincen‐5(6)‐enone G ( 2 ), together with four known diterpenoids, were isolated from the stems of Clerodendrum kaichianum P. S. Hsu . Their structures were elucidated by extensive NMR and MS analyses, and by comparison with literature data. The new compounds showed significant cytotoxicities against the HL‐60 and A‐549 tumor cell lines.     

Diterpenoids from the fruits of Rhododendron molle, potent analgesics for acute pain

Rhododendron molle G. Don is one of the most potent traditional Chinese medicines for pain relief. Prior investigations have shown that Rhododendrons are rich sources of terpenoids. In our continuing efforts to identify structurally unique and biologically interesting diterpenoids, the fruits of R. molle were collected from Guangxi Province. A chemical study was carried out on the EtOH extract, which led to the isolation of 18 diterpenoids including 12 new compounds. The isolation and structural elucidation of new compounds 1–12, as well as the evaluation of the antinociceptive activities of these compounds were reported.     

Preparative isolation of diterpenoids from Salvia bowleyana Dunn roots by high-speed countercurrent chromatography combined with high-performance liquid chromatography

The root of Salvia bowleyana Dunn (Lamiaceae) is used as a traditional Chinese medicine that has multiple therapeutic effects. In this study, an efficient strategy was developed to separate diterpenoid compounds, which are the main active ingredients in Salvia bowleyana Dunn roots, from complex crude extracts by high-speed countercurrent chromatography combined with preparative high-performance liquid chromatography. A two-phase solvent system comprising n-hexane–ethyl acetate–methanol–water (7:3:7:3, v/v/v/v) was selected for high-speed countercurrent chromatographic separation. Three major diterpenoids, 6α-hydroxysugiol ( 7 ), sugiol ( 8 ), and 6, 12-dihydroxyabieta-5,8,11,13-tetraen-7-one ( 9 ) were obtained at purities of 98.9, 95.4, and 96.2%, respectively, and minor diterpenoids were enriched via one-step separation. The enriched minor diterpenoids were further purified by continuous preparative high-performance liquid chromatography to yield two new norabietanoids ( 1 , 6 ) and four known compounds ( 2 – 5 ). The structures of these new compounds were determined using NMR spectroscopy, high-resolution electrospray ionization mass spectrometry, and electronic circular dichroism spectroscopy. The results suggest that high-speed countercurrent chromatography combined with preparative high-performance liquid chromatography efficiently isolates diterpenoids, including minor components, from complex natural products.     

ent‐Kaurane Diterpenoids from Isodon japonicus

Two new 6,7‐seco‐ent‐kaurane diterpenoids, isojaponins A ( 1 ) and B ( 2 ), together with 18 known ent‐kaurane diterpenoids were isolated from the aerial parts of Isodon japonicus. The structures of the two new compounds were elucidated by extensive 1D‐ and 2D‐NMR spectroscopic methods in combination with MS experiments.     

Three new 18-oxygenated ent-kaurane diterpenoids from Isodon leucophyllus

Three new 18-oxygenated ent-kaurane diterpenoids, isoleuconins A-C (1-3) and ten known diterpenoids were isolated from the aerial parts of Isodon leucophyllus. The structures were elucidated by 1D and 2D NMR spectroscopic analysis. All of the compounds were evaluated for their cytotoxicity. Rabdokunmin A (13) showed significant cytotoxicity against HT-29 cells, with an IC50 value of 6.2 microM.     

Daphnane‐Type Diterpenoids from the Flower Buds of Daphne genkwa

Three new daphnane‐type diterpenoids, genkwanines M–O ( 1 – 3 , resp.), together with seven known daphnane‐type diterpenoids, genkwanines D and H, genkwaine F, genkwadaphnine, yuanhuatine, yuanhuafine, and yuanhuapine ( 4 – 10 , resp.), were isolated from the flower buds of Daphne genkwa during a phytochemical investigation. The structures of the new compounds were elucidated on the basis of spectroscopic analyses, especially 2D‐NMR spectra (HSQC, HMBC, and NOESY).     

Diterpenoids from Isodon Eriocalyx

Two new diterpenoids, Maoecrystal U and epi‐maoecrystal P , together with nine known diterpenoids and eight other known compounds were isolated from Isodon eriocalyx ( ). The structures of two new diterpenoids were elucidated as 6β‐acetoxy‐15β‐hydroxy‐3α,20‐epoxy‐ent‐kaur‐16‐ene‐1,7‐dione and 16(S)‐methoxymethy‐6β,7β‐dihydroxy‐7α,20‐epoxy‐ent‐kaur‐2,3‐ethenylene‐1,15‐dione on the basis of spectroscopic evidence, especially by 2D NMR techniques.     

Study of the secretion from a scale insect (Ceroplastes ceriferus) diterpenoids and sesterterpenoids

Structures of four new minor sesterterpenoids 1–3,18 and three new diterpenoids 12–14 isolated from the secretion of Ceroplastes ceriferus are described. All four sesterterpenoids are 14-membered monocyclic compounds; one of them has been chemically correlated with cericeroic acid¹ of proven absolute stereochemistry. The “cyclic wax” was a complex mixture of esters consisting of fatty acids (C₁₀-C₃₂) and unusual cyclic alcohols (diterpenoids and sesterterpenoids)     

Diterpenoids from Salvia ceratophylla

Salvia ceratophylla L. has yielded four known and two new diterpenoids together with two triterpenic acids, a steroid and a flavone. The structures of the compounds were established by spectroscopic analyses. One of the known compounds candidissiol exhibited a high antibacterial activity against Staphylococcus epidermidis and Proteus mirabilis.     

Stepwise Diagnostic Product Ions Filtering Strategy for Rapid Discovery of Diterpenoids in Scutellaria barbata Based on UHPLC-Q-Exactive-Orbitrap-MS

Diterpenoids are considered the major bioactive components in Scutellaria barbata to treat cancer and inflammation, but few comprehensive profiling studies of diterpenoids have been reported. Herein, a stepwise diagnostic product ions (DPIs) filtering strategy for efficient and targeted profiling of diterpenoids in Scutellaria barbata was developed using UHPLC-Q-Exactive-Orbitrap-MS. After UHPLC-HRMS/MS analysis of six diterpenoid reference standards, fragmentation behaviors of these references were studied to provide DPIs. Then, stepwise DPIs filtering aimed to reduce the potential interferences of matrix ions and achieve more chromatographic peaks was conducted to rapidly screen the diterpenoids. The results demonstrated that stepwise DPIs were capable of simplifying the workload in data post-processing and the effective acquisition of low abundance compounds. Subsequently, DPIs and MS/MS fragment patterns were adopted to identify the targeted diterpenoids. As a result, 381 diterpenoids were unambiguously or tentatively identified, while 141 of them with completely new molecular weights were potential new diterpenoids for Scutellaria barbata. These results demonstrate that the developed stepwise DPIs filtering method could be employed as an efficient, reliable, and valuable strategy to screen and identify the diterpenoid profile in Scutellaria barbata. This might accelerate and simplify target constituent profiling from traditional Chinese medicine (TCM) extracts.     

Cytotoxic cassane diterpenoids from the seeds of Caesalpinia sappan

Phytochemical investigation on the seeds of Caesalpinia sappan led to the isolation of five new cassanetype diterpenoids, named 11-oxo-phanginin A(1), caesalsappanins O–Q(2–4) and phanginin U(5),together with five known compounds. The structures of the new compounds were elucidated by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. All the new compounds showed moderate cytotoxic effects on human breast cancer MCF-7 and human colon cancer HCT116 cell lines.