Three New Clerodane Diterpenoids from the Bulbils of Dioscorea bulbifera L. var. sativa

From the bulbils of Dioscorea bulbifera L. var. sativa, three new clerodane diterpenoids, bafoudiosbulbin C (=methyl (2β,8α,12S)‐17‐oxo‐2,19 : 8,19 : 12,17 : 15,16‐tetraepoxycleroda‐3,13(16), 14‐triene‐18‐carboxylate; 1 ), bafoudiosbulbin D (=methyl (2β,6β,12R)‐17,19‐dioxo‐2,19 : 6,17 : 8,12 : 15,16‐tetraepoxycleroda‐13(16),14‐diene‐18‐carboxylate; 2 ), and bafoudiosbulbin E (=methyl (2β,3α,4α,6β,12R)‐17,19‐dioxo‐2,19 : 3,4 : 6,17 : 8,12 : 15,16‐pentaepoxycleroda‐13(16),14‐diene‐18‐carboxylate; 3 ) were isolated, together with the known compounds bafoudiosbulbins A and B, 3‐O‐β‐D ‐glucopyranosyl‐β‐sitosterol, and 6′‐stearoyl‐3‐O‐β‐D ‐glucopyranosyl‐β‐sitosterol. Their structures were established by high‐field NMR techniques (¹H,¹H‐COSY, ¹³C‐DEPT, HSQC, HMBC, and NOESY), MS analyses, as well as by comparison of their spectral data with those of related compounds.     

neo‐Clerodane Diterpenoids from the Aerial Part of Scutellaria barbata

Three new neo‐clerodane diterpenoids, barbatellarines C–E ( 1 – 3 ), were isolated from the CHCl₃‐soluble fraction of the aerial part of Scutellaria barbata. Their chemical structures were elucidated by detailed analysis of NMR and MS data. Compounds 1 and 2 were C(13) epimers, which was confirmed by an NOE difference experiment and the NOESY spectrum. The relative configuration was determined on the basis of the ¹H‐NMR J‐value and NOE data, while the absolute configuration of the previously isolated analogue, barbatellarine B ( 4 ), as a representative member of the group, was assigned by CD analysis.     

Two New Diterpenoids and Other Constituents from Isodon japonicus

Two new ent‐kaurene diterpenoids, 15α,20‐dihydroxy‐6,7‐seco‐entkaur‐16‐ene‐7,1α(6,11α)‐diolide ( 1 ), 6β‐butyroxy‐3β‐hydroxy‐6,7‐seco‐6,20‐epoxy‐7,1α‐olide‐entkaur‐16‐en‐15‐one ( 2 ), together with 25 known compounds, 3 – 27 , were isolated from the leaves of Isodon japonicus. Their structures were established by spectroscopic methods, including 2D‐NMR techniques.     

Two New Furanoid Diterpenoids from Tinospora sagittata

Two new clerodane‐based furanoid diterpenoids, tinosagittones A and B ( 1 and 2 , resp.), were isolated from the roots of Tinospora sagittata, together with five known diterpenoids, i.e., columbin ( 3 ), its glucoside palmatoside C ( 4 ), isocolumbin ( 5 ), 6‐hydroxycolumbin ( 6 ), and tinophylloloside ( 7 ). Their structures were established by mass spectrometry and spectroscopic methods, especially 2D‐NMR techniques.     

Splendidins A – C,Three New Clerodane Diterpenoids from Salvia splendens

Three new clerodane diterpenoids, splendidins A–C ( 1 – 3 , resp.), were isolated from Salvia splendens, together with six known ones. Their structures were elucidated by extensive spectroscopic analysis. Splendidin C ( 3 ) was the first diterpenoid glucoside reported from this plant. These compounds were evaluated for their cytotoxic activity; however, none of them were cytotoxic.     

Two New Diterpenoids from Callicarpa pedunculata

Two new diterpenoids, pedunculatic acid A (= (4R,5α,7α)‐7‐ethoxy‐9β,13β‐dioxyabiet‐8(14)‐en‐18‐oic acid; 1 ) and pedunculatic acid B (= (4S,5α,12β)‐8β,14β‐epoxy‐12‐hydroxy‐11‐oxototaran‐19‐oic acid; 2 ), together with three known sesquiterpenoids, were isolated from the Chinese medicinal herb Callicarpa pedunculata R. Brown . Their structures were elucidated by spectroscopic analyses, including 1D‐ and 2D‐NMR, and by high‐resolution mass spectrometry.     

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.     

Two ent‐Kaurane Diterpenoids from Rubus corchorifolius L. f.

A further chemical investigation of the plant Rubus corchorifolius L. f., collected in Hunan Province, afforded two new ent‐kauranoids 6 and 7 . Their structures were elucidated by various spectroscopic methods.     

Structure Elucidation of Two New Diterpenoids from Isodon phyllostachys: Phyllostacins A and B

Two new ent‐kaurane‐derived diterpene derivatives, phyllostacins A ( 1 ) and B ( 2 ), were isolated from the aerial parts of Isodon phyllostachys, together with two known compounds, irroratin A ( 3 ) and serrin B ( 4 ). Both 1 and 2 were found to be present as diastereoisomers. In the case of 1 , the corresponding diastereoisomeric diacetates 5 and 6 were prepared and separated. The structures of the new compounds were elucidated by extensive 1D‐ and 2D‐NMR spectroscopic methods, in combination with MS experiments. In (D₅)pyridine solution, the two epimers of 1 are present in equal amounts, but in CDCl₃ or CD₃OD, the (S)‐epimer predominates in the mixture of hemiacetals.     

ent‐Kaurane Diterpenoids from Isodon phyllostachys

Phytochemical investigation of the medicinal plant Isodon phyllostachys led to the isolation of four new ent‐kaurane diterpenoids, phyllostacins F–I ( 1 – 4 , resp.), together with 11 known compounds, rosthorin A ( 5 ), rabdoternin C ( 6 ), enmenol ( 7 ), oridonin ( 8 ), lasiocarpanin ( 9 ), xerophilusin B ( 10 ), ponicidin ( 11 ), macrocalin B ( 12 ), phyllostachysin A ( 13 ), sculponeatin C ( 14 ), and macrocalyxoformin E ( 15 ). The structures of the new compounds were established by spectroscopic methods, including extensive 1D‐ and 2D‐NMR analyses. Compounds 1, 2, 7, 10 , and 13 were evaluated for their inhibitory activity against K562 and HepG2 cell lines.     

Two Novel Triterpenoids from Portulaca oleracea L.

Two novel triterpenoids, (2α,3α)‐3‐{[4‐O‐(β‐D ‐glucopyranosyl)‐β‐D ‐xylopyranosyl]oxy}‐2,23‐dihydroxy‐30‐methoxy‐30‐oxoolean‐12‐en‐28‐oic acid ( 1 ) and (2α,3α)‐2,23,30‐trihydroxy‐3‐[(β‐D ‐xylopyranosyl)oxy]olean‐12‐en‐28‐oic acid ( 2 ) were isolated from Portulaca oleracea L., and they both showed weak cytotoxic activity assayed with the MTT method.     

Two Novel Abietane Diterpenoids from Illicium wardii A.C.Sm.

Two novel abietane diterpenoids, wardinols A and B ( 1 and 2 , resp.), together with five known diterpenoids, 3 – 7 , were isolated from the fruits of Illicium wardii A.C.Sm . Their structures were elucidated on the basis of intensive spectroscopic analysis, including 1D‐ and 2D‐NMR spectroscopy. Wardinol A ( 1 ) is a rare 9,10‐epoxy‐9,10‐secoabietane diterpenoid. All of the isolated compounds were evaluated for their cytotoxicities against three human tumor cell lines, A549, HCT116, and CCRF‐CEM.     

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).     

Clerodane Diterpenoids from an Edible Plant Justicia insularis: Discovery,Cytotoxicity, and Apoptosis Induction in Human Ovarian Cancer Cells

Objectives: The toxicity of chemotherapeutic anticancer drugs is a serious issue in clinics. Drug discovery from edible and medicinal plants represents a promising approach towards finding safer anticancer therapeutics. Justicia insularis T. Anderson (Acanthaceae) is an edible and medicinal plant in Nigeria. This study aims to discover cytotoxic compounds from this rarely explored J. insularis and investigate their underlying mechanism of action. Methods: The cytotoxicity of the plant extract was evaluated in human ovarian cancer cell lines and normal human ovarian surface epithelia (HOE) cells using a sulforhodamine B assay. Bioassay-guided isolation was carried out using column chromatography including HPLC, and the isolated natural products were characterized using GC-MS, LC-HRMS, and 1D/2D NMR techniques. Induction of apoptosis was evaluated using Caspase 3/7, 8, and 9, and Annexin V and PI based flow cytometry assays. SwissADME and SwissTargetPrediction web tools were used to predict the molecular properties and possible protein targets of identified active compounds. Key finding: The two cytotoxic compounds were identified as clerodane diterpenoids: 16(α/β)-hydroxy-cleroda-3,13(14)Z-dien-15,16-olide (1) and 16-oxo-cleroda-3,13(14)E-dien-15-oic acid (2) from the Acanthaceous plant for the first time. Compound 1 was a very abundant compound (0.7% per dry weight of plant material) and was shown to be more potent than compound 2 with IC₅₀ values in the micromolar range against OVCAR-4 and OVCAR-8 cancer cells. Compounds 1 and 2 were less cytotoxic to HOE cell line. Both compounds induced apoptosis by increasing caspase 3/7 activities in a concentration dependent manner. Compound 1 further increased caspase 8 and 9 activities and apoptosis cell populations. Compounds 1 and 2 are both drug like, and compound 1 may target various proteins including a kinase. Conclusions: Clerodane diterpenoids (1 and 2) in J. insularis were identified as cytotoxic to ovarian cancer cells via the induction of apoptosis, providing an abundant and valuable source of hit compounds for the treatment of ovarian cancer.     

Highly Acylated 3,4‐Secograyanane Diterpenoids from the Fruits of Pieris formosa

From the fruits of Pieris formosa, four new highly acylated 3,4‐secograyanane diterpenoids, secorhodomollolides E–H ( 1 – 4 , resp.), along with two known ones, secorhodomollolides C and D ( 5 and 6 , resp.), were obtained. Their structures were established mainly by spectroscopic methods, including 1D‐ and 2D‐NMR spectroscopy, and mass spectrometry.     

Bisyinshanic Acids A and B,Two Novel Diterpene Dimers from the Roots of Euphorbia yinshanica

Two novel diterpene dimers with a bismagdalenic acid skeleton, bisyinshanic acids A and B ( 1 and 2 , resp.), along with eight known diterpenoids ( 3 – 10 ), were isolated from the roots of Euphorbia yinshanica. Their structures were elucidated on the basis of spectroscopic evidence.     

Paecilomycines A and B,Novel Diterpenoids,Isolated from Insect‐Pathogenic Fungi Paecilomyces sp. ACCC 37762

Two new diterpenoids, named paecilomycine A ( 1 ) and paecilomycine B ( 2 ), including a novel skeleton with a five‐membered lactone ring, together with three known labdane diterpenoids, rel‐(1R,3S,4aS,5R,8aS)‐5‐[(3E)‐4‐carboxy‐3‐methylbut‐3‐en‐1‐yl]decahydro‐3‐hydroxy‐1,4a‐dimethyl‐6‐methylidenenaphthalene‐1‐carboxylic acid ( 3 ), botryosphaerin E ( 4 ), and agathic acid ( 5 ), were isolated from solid culture of the insect pathogenic fungi strain Paecilomyces sp. The structures of all compounds were established on the basis of comprehensive spectroscopic studies. The relative configurations of 1 and 2 were determined by single‐crystal X‐ray diffraction analyses.     

A Novel Atisane Diterpenoid from Spiraea japonica var. acuta

A novel ent‐atisane lactone, spiramilactone E ( 1 ), was isolated from Spiraea japonica var. acuta Yu . Its structure was elucidated by extensive spectroscopic analyses, and unequivocally confirmed by single‐crystal X‐ray diffraction (Fig. 2). Compound 1 contains a γ‐lactone moiety between the 6‐OH function and C(20), and β‐configuration for the 7‐OH group, in contrast to known related diterpenes previously isolated from the S. japonica complex.     

Verticillane‐Type Diterpenoids and an Eudesmanolide‐Type Sesquiterpene from the Formosan Soft Coral Cespitularia hypotentaculata

Four new diterpenes, cespihypotins W–Z ( 1 – 4 ), having the verticillane skeleton and characterized by an α,β‐unsaturated γ‐hydroxycyclopentanone moiety, and a new eudesmanolide‐type sesquiterpene, cespilactam A ( 5 ), containing an α,β‐unsaturated γ‐lactam residue, were isolated from the AcOEt‐soluble fraction of the Taiwanese soft coral Cespitularia hypotentaculata. The structure and relative configuration of these metabolites was elucidated through extensive interpretation of MS, COSY, HSQC, HMBC, and NOESY experiments and by comparison of their NMR data with those of related compounds.     

Chemical composition and biological activities of the essential oil from Pulicaria undulata (L.) C. A. Mey. growing wild in Egypt

Abstract

Pulicaria undulata is used as a traditional herbal remedy in Egypt. We used gas chromatography-mass spectrometry for analysis of essential oil of this plant growing wild in Egypt and 64 compounds were identified. The oil was rich in oxygenated monoterpenes (64.0%) and aromatic derivatives (18.8%). The major components were carvacrol (46.5%), xanthoxylin (18.1%) and carvotanacetone (8.7%). The oil of the Egyptian plant showed significant differences from the oil results reported on this species derived from different accessions. Antioxidant activity was performed by FRAP, DPPH and ABTS assays, and the oil demonstrated a powerful antioxidant properties. Furthermore, cytotoxicity was assessed using MTT assay against three cell lines (A375, T98G, HCT116) and the oil showed moderate results with IC₅₀ of 18.53, 40.64 and 22.23?μg/ml; respectively. The oil showed a good anti-acetylcholinesterase activity (IC₅₀?=?139.2?μg/ml) using Ellman method. In conclusion, the studied oil exhibited a peculiar fingerprint and promising biological activities.