New Triterpenoid Glycosides from the Roots of Camellia oleifera Abel

Five new triterpenoid saponins, oleiferosides I–M ( 1 – 5 , resp.) were isolated from the roots of Camellia oleifera Abel . Their structures were elucidated by a combination of 1D‐ and 2D‐NMR spectroscopy, mass spectrometry, and chemical methods. All the compounds were identified as oleanane‐type saponins with sugar moieties linked to C(3) of the aglycone. In addition, cytotoxic activities of these saponins were evaluated against four human tumor cell lines (A549, B16, BEL‐7402, and MCF‐7) by using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) in vitro assay. All of the compounds showed significant cytotoxic activities against the tested cell lines.     

Isolation and Characterization of Bioactive Cyclotides from Viola labridorica

Many Violaceae plants contain cyclotides, which are plant cyclopeptides distinguished by a cyclic cystine knot motif with 28–37 amino acid residues. In the current study, four new cyclotides, vila A–D ( 1 – 4 , resp.), together with a known cyclotide, varv D ( 5 ), were isolated from Viola labridorica (Violaceae). A chromatography‐based method was used to isolate the cyclotides, which were characterized using tandem mass spectrometry and 2D‐NMR spectroscopy. Several of the cyclotides showed cytotoxic activities against five cancer cell lines, i.e., U251, MDA‐MB‐231, A549, DU145, and BEL‐7402, with vila A and B ( 1 and 2 , resp.) being the most cytotoxic. The isolated cyclotides showed no antibacterial activity against Staphyloccocus aureus and Candida albicans. Homology modeling of the cyclotide structures was used to analyze structure–activity relationships.     

Pyrrolizidine Alkaloids and Bisabolane Sesquiterpenes from the Roots of Ligularia cymbulifera

The new pyrrolizidine alkaloid glycoside 1 , and the three new highly oxygenated bisabolane sesquiterpenes 4 – 6 , together with the two known pyrrolizidine alkaloids 2 and 3 , were isolated from the roots of Ligularia cymbulifera (W. W. Smith ) Hand .‐Mazz . Their structures were established on the basis of spectroscopic analysis, especially 1D‐ and 2D‐NMR data. The cytotoxic activities of compounds 1, 2 , and 4 – 6 were evaluated against hepatoma (BEL‐7402), human leukemia (HL‐60), human ovarian carcinoma (HO‐8910), and nasopharyngeal carcinoma (KB) cell lines (Tables 1–3). Compound 6 s howed weak cell‐growth inhibition of BEL‐7402 cell.     

A New Nortriterpene from the Root of Celastrus hypoleucus

A new nortriterpene, 2‐hydroxy‐3‐methyl‐21‐oxo‐12,24‐dinor‐D : B‐friedooleana‐1,3,5(10),7‐tetraen‐29‐oic acid ( 1 ), was isolated from the root of Celastrus hypoleucus, together with the two known compounds, celastorol ( 2 ) and pristimerine ( 3 ). Their structures were elucidated on the basis of spectroscopic analyses. Compounds 1 – 3 exhibited in vitro significant antioxidant (against lipid peroxidation; by the TBARS method) and antitumor activities (against cancer cell lines P‐388, A‐549, HL‐60, and BEL‐7402).     

Three New 3,6‐Dioxygenated Diketopiperazines from the Basidiomycete Lepista sordida

Three new 3,6‐dioxygenated diketopiperazines, lepistamides A–C ( 1 – 3 ), along with a known compound, diatretol ( 4 ), were isolated from the mycelial solid cultures of the basidiomycete Lepista sordida. Their structures were elucidated by spectroscopic means. The isolated diketopiperazines were evaluated for the cytotoxic activity against Astc‐a‐1, Bel 7402, and HeLa cell lines, and their biogenetic pathway was discussed.     

Sesquiterpene Lactones from Daucus glaber

Six new sesquiterpene lactone esters, daucoguaianolactones A–F ( 1 – 6 ), and one new sesquiterpene lactone, daucoeudesmanolactone A ( 7 ) were isolated from the leaves and stems of Daucus glaber (Forssk .) Thell ., along with the known sesquiterpene lactones talasins A and B and badkhysin. The structures of 1 – 6 were established on the basis of extensive 1D‐ and 2D‐NMR spectroscopic studies and that of 7 by X‐ray crystallography. Compounds 4, 7 , and talasins A and B showed moderate cytotoxicity against P‐388 leukemia cells.     

Pintoxolanes A–C,Highly Functionalized 3,14‐Oxa‐bridged Cembranoids from the Caribbean Gorgonian Coral Eunicea pinta

Three new cembrane‐based diterpenes possessing the rare 3,14‐oxa‐bridged moiety were isolated from the hexane extract of a southwestern Caribbean gorgonian octocoral, Eunicea pinta, together with seven known cembranoid diterpenes. The structures of pintoxolanes A–C ( 1 – 3 , resp.), including their relative configurations, were deduced from spectroscopic data and chemical‐correlation experiments. Experimental evidence hinting to a plausible biogenesis of the 3,14‐oxalane moiety is provided. Preliminary cytotoxicity data for compounds 1 – 3 toward human cancer cell lines are also provided.     

New Cytotoxic Myrsinane‐Type Diterpenes from Euphorbia prolifera

Four new myrsinol diterpenes, proliferins A–D ( 1 – 4 , resp.) were isolated from the EtOH extracts of the roots of Euphorbia prolifera, along with four known compounds, euphorprolitherin B ( 5 ), euphorprolitherin D ( 6 ), SPr5 ( 7 ), and 14‐desoxo‐3‐O‐propionyl‐5,15‐di‐O‐acetyl‐7‐O‐nicotinoylmyrsinol‐14β‐acetate ( 8 ). Their structures were established on the basis of spectroscopic methods, including HR‐ESI‐MS, and 1D‐ and 2D‐NMR techniques. The cytotoxicity of compounds 1, 3 , and 4 against cancer cells was evaluated, with compound 1 being active against A2780 cancer cells.     

Three New Bisabolane Sesquiterpenes from Ligularia songarica

Three new bisabolane sesquiterpenes, songaricalarins F–H ( 1 – 3 , resp.), and five known analogs, 4 – 8 , were isolated from roots and rhizomes of Ligularia songarica. The structures were elucidated by spectroscopic methods, including 2D‐NMR techniques. The isolated compounds were also evaluated for their cytotoxic activities, against human lung carcinoma (A‐549) and human breast adenocarcinoma (MCF‐7) cell lines, and three compounds were found to show moderate cytotoxicities.     

Cytotoxic Terpenoids from Turraea pubescens

Three new triterpenoids, turrapubesols A–C ( 1 – 3 ), and one new sesquiterpenoid, 1α,4α‐dihydroxyeudesman‐11‐ene ( 4 ), along with 12 known terpenoids were isolated from Turraea pubescens. The structures of the terpenoids were established on the basis of extensive spectroscopic analyses and by a chemical transformation. The previous assignment of the NMR data for guaidiol ( 5 ) was corrected. Some of the triterpenoids exhibited cytotoxicity against the P‐388 cell line.     

Four New Nortriterpenoids from Schisandra lancifolia

Four new highly oxygenated nortriterpenoids, lancifodilactones O–R ( 1 – 4 ), together with six known ones, i.e., 5 – 10 , were isolated from the leaves and stems of Schisandra lancifolia. Their structures were elucidated by spectroscopic analyses, including 1D‐ and 2D‐NMR experiments and mass spectrometry. Compounds 1 – 3 were evaluated for their cytotoxicity against NB4, A549, SHSY5Y, PC‐3, and MCF‐7 cell lines. No compounds exhibited significant cytotoxicity, the IC₅₀ values being above 50 μM .     

Three New ent‐Labdane Diterpenoids from the Wood of Excoecaria agallocha Linn.

An extensive study of metabolites present in Excoecaria agallocha Linn . led to the isolation of three new ent‐labdane‐type diterpenoids, named agallochaexcoerins A–C ( 1 – 3 ), besides three known compounds. The skeleton present in compound 1 is rather unusual, containing of a seven‐membered lactone. The structures were elucidated on the basis of spectroscopic studies and comparison with known related compounds. The isolated compounds 1 – 6 were not active against Raw 264.7 (macrophage‐like), K 562 (leukemia), and COLO 205 (colon) human carcinoma cell lines.     

New Cembrane Diterpenes from Taiwanese Soft Coral Sinularia flexibilis

A chemical investigation of the Taiwanese soft coral Sinularia flexibilis has resulted in the isolation of three new cembrane diterpenes designated sinuladiterpenes G–I ( 1 – 3 , resp.). The structures of 1 – 3 were determined on the basis of spectroscopic analyses, especially 2D‐NMR and HR‐ESI‐MS.     

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.     

Three New Diterpenoids from Isodon nervosus

Three new ent‐kaurane diterpenoids, rabdonervosins D–F ( 1 – 3 ), were isolated from the leaves and stems of Isodon nervosus. Their structures were elucidated on the basis of spectroscopic methods including 1D‐ and 2D‐NMR analyses. Compounds 1 – 3 were evaluated for their cytotoxicity against HepG2, CNE2, PC‐9/ZD, HeLa, MCF‐7, and HCT116 cell lines. No compounds exhibited potent cytotoxicity.     

Tricycloalternarenes A – E: Five New Mixed Terpenoids from the Endophytic Fungal Strain Alternaria alternata Ly83

Five new mixed terpenoids, tricycloalternarenes (TCAs) A–E ( 1 – 5 ), together with two known compounds, TCA 1b ( 6 ) and TCA 2b ( 7 ), were isolated from the solid‐state‐cultured endophytic fungus Alternaria alternata of Maytenus hookeri. Their structures were identified by extensive spectroscopic (especially 2D‐NMR) experiments. Compound 7 showed weak activity against human tumor cell lines by MTT assay.     

Phochinenins A – F,Dimeric 9,10‐Dihydrophenanthrene Derivatives,from Pholidota chinensis

Six new compounds, phochinenins A–F ( 1 – 6 ), dimerized from 9,10‐dihydrophenanthrene and dihydrostilbene through direct coupling or an oxygen bridge, along with eight known compounds, were isolated from the whole plants of Pholidota chinensis. Their structures were elucidated on the basis of extensive spectroscopic investigations (1D‐, 2D‐NMR, and HR‐EI‐MS).     

Norlignans and Phenylpropanoids from Metasequoia glyptostroboides Hu et Cheng

Five new compounds, i.e., the three new norlignans metasequirins G–I ( 1 – 3 ) and the two new phenylpropanoids 7‐(3‐ethoxy‐5‐methoxyphenyl)propane‐7,8,9‐triol (=1‐(3‐ethoxy‐5‐methoxyphenyl)propane‐1,2,3‐triol; 4 ) and 7‐(3‐hydroxy‐5‐methoxyphenyl)propane‐7,8,9‐triol (=1‐(3‐hydroxy‐5‐methoxy‐phenyl)propane‐1,2,3‐triol; 5 ), were isolated from the branches and stems of Metasequoia glyptostroboides Hu et Cheng . Their structures were elucidated by physical, chemical, and spectroscopic methods, including 1D‐ and 2D‐NMR and HR‐ESI‐MS. The cytotoxicites of the five compounds were tested against A549 and Colo 205 cell lines by the MTT method.     

Cytotoxic Diterpenes from the Root Tuber of Curcuma wenyujin

Bioassay‐guided fractionation of ethanolic extract from the root tuber of Curcuma wenyujin afforded three new diterpenes, curcumrinols A–C ( 1 – 3 ), where 2 is the (14S)‐epimer of 1 . The structures of 1 – 3 were established on the basis of spectroscopic analysis, mainly NMR and MS. 1 – 3 were tested in vitro for their cytotoxic activity against the HL‐60 and K562 cancer cells. Among the compounds tested, 1 exhibited medium cytotoxicity against K‐562 and HL60 human cancer cells with IC₅₀ values of 11.2 and 3.2 μg/ml, respectively. However, 2 showed only weak activity against the above cancers cells, which suggested that C(14) may be an important position for cytotoxic activity.     

Kadsufolins A – D and Related Cytotoxic Lignans from Kadsura oblongifolia

Kadsufolins A–D ( 1 – 4 , resp.), four new dibenzocyclooctane‐type lignans, were isolated from the roots and stems of Kadsura oblongifolia, together with eleven known lignans. Their structures and configurations were elucidated by spectroscopic methods including 2D‐NMR techniques. The compounds were also evaluated for cytotoxic activity against human tumor cell lines A549 (lung carcinoma), DU145 (prostate carcinoma), KB (epidermoid carcinoma of the nasopharynx), and HCT‐8 (ileocecal carcinoma). Kadsufolin A ( 1 ), kadsufolin D ( 4 ), angeloylbinankadsurin A, and heteroclitin B were found to show cytotoxic activities against A549, DU145, KB and HCT‐8 with GI₅₀ values of 5.1–20.0 μg/ml.