New Eunicellin Diterpenes and 9,10‐Secosteroids from the Gorgonian Muricella sibogae

Bioactivity‐guided isolation of the rare gorgonian Muricella sibogae (Nutting ) yielded the two new eunicellin diterpenes sibogin A and B ( 1 and 2 ), the three new 9,10‐secosteroids sibogol A–C ( 6 – 8 ), together with the three known eunicellin diterpenes 3 – 5 and the five known 9,10‐secosteroids 9 – 13 . Their structures were established by extensive spectral analysis (1D‐ and 2D‐NMR, IR, and MS). The cytotoxicity of the isolates 1 – 13 was evaluated in vitro against the selected tumor cell lines P388 and BEL‐7402. All the compounds showed only weak activity against P388 cell lines, with an inhibition rate ranging from 10 to 60% at a concentration of 50 μg/ml, whereas the were inactive against BEL‐7402 cell lines.     

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.     

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).     

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.     

Two New Polyoxygenated Triterpenoids from Actinidia valvata

Two new polyoxygenated triterpenoids, (2β,3α,6α)‐2,3,6,20,23,30‐hexahydroxyurs‐12‐en‐28‐oic acid ( 1 ) and (2β,3α)‐2,3,20,23,24,30‐hexahydroxyurs‐12‐en‐28‐oic acid O‐β‐D ‐glucopyranosyl ester ( 2 ) were isolated from the roots of Actinidia valvata Dunn . Their structures were elucidated by means of extensive spectroscopic studies. Both compounds showed moderate cytotoxic activity in vitro against the BEL‐7402 and SMMC‐7721 tumor cell lines.     

Diterpenoids from the Hainan Soft Coral Sinularia parva

Two new cembrane diterpenes, sinulaparvalides A and B ( 1 and 2 , resp.), which contain an intriguing seven‐membered lactone moiety, along with the four known related cembranoids 3 – 6 , were isolated from the Hainan soft coral Sinularia parva. The structures of compounds 1 and 2 were established by spectroscopic methods, mainly on the basis of 2D‐NMR techniques, and were confirmed by single‐crystal X‐ray diffraction analysis. The in vitro cytotoxic activities of these compounds were tested on human colon carcinoma (HCT‐116), human promyelocytic leukemia (HL‐60), and human lung carcinoma (A‐549) tumor cell lines.     

Seven New Acyl Glycosides from Erycibe obtusifolia

Seven new acyl glycosides, benzyl 5‐O‐vanilloyl‐β‐d ‐apiofuranosyl‐(1→6)‐β‐d ‐glucopyranoside ( 1 ), 4‐hydroxy‐3‐methoxyphenyl 5‐O‐syringoyl‐β‐d ‐apiofuranosyl‐(1→6)‐β‐d ‐glucopyranoside ( 2 ), isopentyl 5‐O‐syringoyl‐β‐d ‐apiofuranosyl‐(1→6)‐β‐d ‐glucopyranoside ( 3 ), 3,4,5‐trimethoxyphenyl 5‐O‐sinapoyl‐β‐d ‐apiofuranosyl‐(1→6)‐β‐d ‐glucopyranoside ( 4 ), 6‐methoxy‐7‐[(6‐O‐sinapoyl‐β‐d ‐glucopyranosyl)oxy]coumarin ( 5 ), 6‐methoxy‐7‐[(2‐O‐sinapoyl‐β‐d ‐glucopyranosyl)oxy]coumarin ( 6 ), and isopentyl β‐d ‐apiofuranosyl‐(1→6)‐[5‐O‐syringoyl‐β‐d ‐apiofuranosyl‐(1→2)]‐β‐d ‐glucopyranoside ( 7 ), were isolated from Chinese folk herb Erycibe obtusifolia. Their structures were elucidated on the basis of extensive spectroscopic analysis, including UV, IR, MS, and 1D‐ and 2D‐NMR techniques. Further, these compounds were evaluated against HCT‐8 (human colon carcinoma), Bel‐7402 (human liver carcinoma), BGC‐823 (human stomach carcinoma), A549 (human lung carcinoma), and A2780 (human ovarian carcinoma) cell lines, however, none of them exhibited a significant bioactivity (IC₅₀ > 10 μm ).     

New Briaranes from the South China Sea Gorgonian Junceella fragilis

Three new briarane diterpenes, junceellonoids C–E ( 1 – 3 ), along with six known briaranes, junceellin A ( 4 ), praelolide ( 5 ), and junceellolides A‐D ( 6 – 9 ), were isolated from the EtOH/CH₂Cl₂ extracts of the South China Sea gorgonian coral Junceella fragilis. The structures of 1 – 3 were established by extensive spectroscopic analysis, including 1D‐ and 2D‐NMR data. Compounds 1 and 2 exhibited mild cytotoxicity against human galactophore carcinoma (MDA‐mB‐231 and MCF‐7) cells at the concentration of 100 μM .     

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.     

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.     

Musellactone,A New Lactone From Musella Lasiocarpa

A new lactone ( 1 ), named musellactone, was isolated from the aerial parts of Musella lasiocarpa, along with eight known compounds. The structures were chemically characterized by spectroscopic methods. Musellactone ( 1 ), and 2‐methyl‐9‐(4′‐hydroxyphenyl)‐phenalen‐1‐one ( 2 ), showed different effects against five bacteria strains, and 1,2,3,4‐tetrahydro‐1,2‐dimethyl‐6,7‐isoquinolinediol ( 3 ), showed significant cytotoxic activities in vitro against KB, HL‐60 and BEL‐7404 human carcinoma cell lines.     

Two New Cytotoxic Nonsulfated Pentasaccharide Holostane (=20‐Hydroxylanostan‐18‐oic Acid γ‐Lactone) Glycosides from the Sea Cucumber Holothuria grisea

Two new lanostane‐type nonsulfated pentasaccharide triterpene glycosides, 17‐dehydroxyholothurinoside A ( 1 ) and griseaside A ( 2 ), were isolated from the sea cucumber Holothuria grisea. Their structures were elucidated by spectroscopic methods, including 2D‐NMR and MS experiments, as well as chemical evidence. Compounds 1 and 2 possess the same pentasaccharide moieties but differ slightly in their side chains of the holostane‐type triterpene aglycone. The structures of the two new glycosides were established as (3β,12α)‐22,25‐epoxy‐3‐{(O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[O‐3‐O‐methyl‐β‐D ‐glucopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranosyl‐(1→4)‐6‐deoxy‐β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐xylopyranosyl)oxy}‐12,20‐dihydroxylanost‐9(11)‐en‐18‐oic acid γ‐lactone ( 1 ) and (3β,12α)‐3‐{(O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[O‐3‐O‐methyl‐β‐D ‐glucopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranosyl‐(1→4)‐6‐deoxy‐β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐xylopyranosyl)oxy}‐12,20,22‐trihydroxylanost‐9(11)‐en‐18‐oic acid γ‐lactone ( 2 ). The 17‐dehydroxyholothurinoside A ( 1 ) and griseaside A ( 2 ) exhibited significant cytotoxicity against HL‐60, BEL‐7402, Molt‐4, and A‐549 cancer cell lines.     

Phytoquinoids and Secoprezizaane‐Type Sesquiterpenes from Illicium arborescens

A phytochemical investigation of the MeOH extract of Illicium arborescens yielded the two new phytoquinoid epimers, 2,3‐didehydro‐5‐O‐methyl‐11‐epiillifunone E ( 1 ) and 2,3‐didehydro‐5‐O‐methylillifunone E ( 2 ), as well as five new sesquiterpene lactones (8,9‐secoprezizaane‐type sesquiterpenes). Two of them, i.e., 3 and 4 , were minwanensin‐type sesquiterpenes, the other two, i.e., 5 and 6 , had the anisatin‐type (or floridanolide type) skeleton, and the fifth, i.e., 7 , was a dunnianin‐type sesquiterpene. Their structures were established by analyses of 1D‐ and 2D‐NMR, HR‐MS, and chemical evidence. The in vitro cytotoxic activity of compounds 1 – 7 was tested against four human tumor cell lines, including HeLa (cervical epitheloid), WiDr (colon), Daoy (medulloblastoma), and Hep2 (liver carcinoma) human‐tumor cells.     

New Clerodane Diterpenoids from Casearia membranacea

Bioassay‐guided fractionation of an AcOEt extract of Casearia membranacea resulted in the isolation of six new clerodane diterpenes, caseamembrins G–L ( 1 – 6 ). The structures of the new compounds, including their relative configurations, were established by an extensive study of their spectral data, especially 2D NMR. The cytotoxic activities of the isolated diterpenes against human oral epidermoid (KB), cervical epitheloid (Hela), and liver (Hep59T/VGH) carcinoma cell lines were investigated.     

Cytotoxic Withaphysalins from Physalis minima

A novel withanolide, withaphysalin P ( 1 ) with a nine‐membered ring, and six other new withaphysalins, 2 – 7 , together with the three known withaphysalins 8 – 10 were isolated from Physalis minima L. The structures were deduced by means of spectroscopic analyses, and that of withaphysalin P ( 1 ) was confirmed by a single‐crystal X‐ray diffraction analysis. Plausible biosynthetic pathways were postulated (Scheme 1). All compounds were tested for their antiproliferative activities toward the human colorectal‐carcinoma HCT‐116 cells and human nonsmall‐cell lung‐cancer NCI‐H460 cells (Table 4). Compounds 1 – 3, 7 – 10, 7a , and 7b displayed moderate cytotoxic activity against the two human cancer cell lines.     

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.     

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.     

Triterpenoid Saponins from the Spikes of Prunella vulgaris

Three new oleanane‐skeleton triterpenoid saponins, 3β,4β,16α‐17‐carboxy‐16,24‐dihydroxy‐28‐norolean‐12‐en‐3‐yl 4‐O‐β‐D ‐xylopyranosyl‐β‐D ‐glucopyranosiduronic acid ( 1 ), (3β,4β,16α)‐17‐carboxy‐16,24‐dihydroxy‐28‐norolean‐12‐en‐3‐yl β‐D ‐glucopyranosiduronic acid methyl ester ( 2 ), and (3β,4β)‐24‐hydroxy‐16‐oxo‐28‐norolean‐12‐en‐3‐yl 4‐O‐β‐D ‐xylopyranosyl‐β‐D ‐glucopyranosiduronic acid ( 3 ), together with eight known constituents, i.e., the oleanane‐type triterpenoids 4 – 6 , and the ursane‐type triterpenoids 7 – 11 , were isolated from the spikes of Prunella vulgaris. The new structures were established by means of detailed spectroscopic analysis (IR, HR‐ESI‐MS, 1D‐ and 2D‐NMR experiments). Compounds 1 – 3 were tested for their inhibition activity against the growth of tumor cell lines; only compound 3 displayed marginal inhibition activity.     

Three New Lignan Derivatives from Lindera glauca (Siebold et Zucc.) Blume

Two new aryl‐tetralin lignan glycosides, linderanosides A and B ( 1 and 2 , resp.), and a new dihydrobenzofuran neolignan glycoside, linderanoside C ( 3 ), together with five known lignan derivatives ( 4 – 8 ) were isolated from the trunk of Lindera glauca. The structures of these new compounds were determined through spectroscopic analyses, including extensive 2D‐NMR data and acid hydrolysis. The absolute configurations of the compounds were clarified by circular dichroism (CD) spectroscopic studies. Compounds 1 – 8 were evaluated for their cytotoxicity against A549 (non‐small cell lung adenocarcinoma), SK‐OV‐3 (ovarian cancer cells), A498 (human kidney epithelial cells), and HCT‐15 (colon cancer cells) human tumor cell lines using sulforhodamine B assays in vitro.     

Indoloquinazoline Alkaloids from Araliopsis tabouensis

Three new indoloquinazolidine‐type alkaloids, 8,13‐dihydro‐2‐methoxyindolo[2′,3′: 3,4]pyrido[2,1‐b]quinazolin‐5(7H)‐one ( 1 ), 8,13‐dihydro‐2‐methoxy‐13‐methylindolo[2′,3′: 3,4]pyrido[2,1‐b]quinazolin‐5(7H)‐one ( 2 ), and 5,8,13,14‐tetrahydro‐2‐methoxy‐14‐methyl‐5‐oxo‐7H‐indolo[2′,3′: 3,4]pyrido[2,1‐b]quinazolim‐6‐iun chloride ( 3 ) were isolated from Araliopsis tabouensis, together with three known compounds. The structures of the new compounds were determined primarily from 1D‐ and 2D‐NMR analysis. The antimalarial activities of compounds 1 – 5 were evaluated against Plasmodium falciparum D6 and W2 clones. The IC₅₀ values in antimalarial bioassay for compounds 2 – 5 varied from 1.8 to 4.7 μg/ml.