Penicidones A-C, three cytotoxic alkaloidal metabolites of an endophytic Penicillium sp

Along with the known secondary metabolites lumichrome, physcion, and emodin-1,6-dimethyl ether, three alkaloids named penicidones A-C (1-3) were isolated from the culture of Penicillium sp. IFB-E022, an endophytic fungal strain residing in the stem of Quercus variabilis (Fagaceae). The structures of penicidones A-C were established by a correlative interpretation of spectroscopic data including IR, UV and HR-ESI-MS, as well as by analysis of a set of 1D and 2D NMR experiments. The stereochemistry of compounds 1 and 2 was obtained by comparison of the optical rotation with those of vermistatin and its analogues. Penicidones A-C were the first group of natural products possessing a penicidone framework. Compounds 1-3 exhibited moderate cytotoxicity against four cancer cell lines.     

ent-Kaurene diterpenoids from Isodon oresbius

Three new ent-kaurene diterpenoids, oreskaurins A-C (1-3), together with ten known ent-kaurene diterpenoids, enmenin monoacetate (4), effusanin E (5), adenolin B (6), maoecrystal G (7), enmelol (8), trichokaurin (9), sodoponin (10), trichorabdal A (11), nodosin (12), enmein (13), and a flavonoid, vitexin (14), were isolated from Isodon oresbius. Their structures were determined by spectroscopic means. Compound 12 showed inhibitory activity toward K562 cells with IC(50)=1.43 microg/ml.     

The phytoalexins from cauliflower, caulilexins A, B and C: isolation, structure determination, syntheses and antifungal activity

Our continuous search for phytoalexins from crucifers led us to examine phytoalexin production in florets of cauliflower (Brassica oleracea var. botrytis) under abiotic (UV light) elicitation. Four known (isalexin, S-(-)-spirobrassinin, 1-methoxybrassitin, brassicanal C) and three new (caulilexins A-C) phytoalexins were isolated. The syntheses and antifungal activity of caulilexins A-C against the economically important pathogenic fungi Leptosphaeria maculans, Rhizoctonia solani and Sclerotinia sclerotiorum, and the first synthesis of brassicanal C are reported.     

Antibacterial and cytotoxic xanthones from the roots of Cratoxylum formosum

Chemical investigation of the roots of Cratoxylum formosum has resulted in the isolation and characterization of xanthones: three new, named formoxanthone A-C and three known together with three known anthraquinones. Their structures were established on the basis of analysis of spectroscopic evidence. In addition, antibacterial and cytotoxic activities of the isolates were also evaluated.     

Thelephantins D-H: five p-terphenyl derivatives from the inedible mushroom Thelephora aurantiotincta

Five p-terphenyl derivatives named thelephantins D-H (1-5) together with nine known compounds, thelephantins A-C (6-8), ganbajunin E (9), p-hydroxylbenzoic acid (10), ganbajunin C (11), thelephorin A (12), 2-O-methylatromentin (13) and atromentin (14), were isolated from the methanolic extract of fruit bodies of the Thelephoraceous Basidiomycete Thelephora aurantiotincta. Their structures were elucidated by high-resolution MS, 2D NMR, IR and UV spectroscopic analysis.     

Iridoid and phenolic glycosides from Morinda coreia

From the leaves and branches of Morinda coreia, six compounds [yopaaosides A-C, 10-O-acetylmonotropein, 6-O-acetylscandoside and 3,4,5-trimethoxyphenyl 1-O-beta-apiofuranosyl (1"-->6')-beta-glucopyranoside] have been isolated together with five known compounds. Structural elucidations were based on analyses of physical and spectroscopic data.     

Bafoudiosbulbins F and G, further clerodane diterpenoids from Dioscorea bulbifera L. var sativa and revised structure of Bafoudiosbulbin B

From the bulbils of Dioscorea bulbifera L. var sativa, two clerodane diterpenoids, Bafoudiosbulbins F (1) and G (2), together with five known compounds: Bafoudiosbulbins A-C, 3,5,4'-trihydroxy-3'-methoxybibenzyl, and kaempferol were isolated. Their structures were established by spectroscopic techniques, including (1)H, (13)C NMR, NOESY, ROESY, COSY, TOCSY, HSQC, and HMBC. The relative stereochemistry of compounds 1 and 2 was assigned on the basis of X-ray crystallographic diffraction analysis. Furthermore, the structure of Bafoudiosbulbin B was revised using extensive 2D NMR techniques as well as chemical transformation.     

Plocoralides A-C, polyhalogenated monoterpenes from the marine alga Plocamium corallorhiza

Three new polyhalogenated monoterpenes, plocoralides A-C (1-3) along with three known compounds (4-6) have been isolated from the organic extract of the red alga P. corallorhiza. Structures of the new compounds were characterized as 4,8-dibromo-1,1-dichloro-3,7-dimethyl-2E,6E-octadiene (1), 4,6-dibromo-1,1-dichloro-3,7-dimethyl-2E,7-octadiene (2) and 4,8-dibromo-1,1,7-trichloro-3,7-dimethyl-2E,5Z-octadiene (3) on the basis of one- and two-dimensional NMR spectroscopic data and MS analyses. Compounds 2-6 show moderate cytotoxicity toward esophageal cancer cells.     

Lanostane triterpenoids from the inedible mushroom Fomitopsis spraguei

Investigation of the methanolic extract of the inedible mushroom Fomitopsis spraguei (Polyporaceae) led to the isolation of five lanostane-type triterpenoids (1-5): three new compounds named fomitopsins A-C (2-4), and two known compounds, quercinic acid C (1) and 3alpha-carboxyacetyl-12beta-hydroxyquercinic acid (5). Their structures were determined by 2D NMR, MS, IR, UV spectra, and X-ray crystallographic analyses. An X-ray crystal structure analysis of quercinic acid C (1) established its stereochemistry as 3R,12R-dihydroxy-24R-methyl-23-oxo-25S-lanost-8-en-26-oic acid.     

Flavone glucosides with immunomodulatory activity from the leaves of Pleioblastus amarus

Three flavone glucosides, pleiosides A-C, were isolated from the leaves of Pleioblastus amarus, along with two known flavones: tricin and tricetin 3,5-dimethoxy-7-O-β-d-glucopyranoside. Their structures were elucidated by extensive spectral studies. Pleiosides A-C were found to inhibit the proliferation of murine T and significantly stimulate the proliferation of murine B lymphocytes in vitro.     

Antioxidative polyphenols from walnuts (Juglans regia L.)

Three hydrolyzable tannins, glansrins A-C, together with adenosine, adenine, and 13 known tannins were isolated from the n-BuOH extract of walnuts (the seeds of Juglans regia L.). Glansrins A-C were characterized as ellagitannins with a tergalloyl group, or related polyphenolic acyl group, based on spectral and chemical evidence. The 14 walnut polyphenols had superoxide dismutase (SOD)-like activity with EC(50) 21.4-190 microM and a remarkable radical scavenging effect against 1,1-diphenyl-2-picrylhydrazyl (DPPH) (EC(50) 0.34-4.72 microM).     

Rare merosesquiterpenoids from basidiomycete Craterellus odoratus and their inhibition of 11β-hydroxysteroid dehydrogenases

Rare merosesquiterpenoids, craterellins A-C (1-3), were isolated from cultures of basidiomycete Craterellus odoratus together with the previously known massarinolin C (4). Structures of 1-3 were elucidated on the basis of extensive spectroscopic analysis. Compounds 1-3 possess a rare, epoxymethylenecyclohexanetriol-bicyclofarnesane sesquiterpene hybrid skeleton. Compounds 1-4 were evaluated for their inhibitory activities against two isozymes of 11β-hydroxysteroid dehydrogenases (11β-HSD1 and 11β-HSD2).     

New bisabolane sesquiterpenoids from a marine-derived fungus Aspergillus sp. isolated from the sponge Xestospongia testudinaria

Three new phenolic bisabolane sesquiterpenoid dimers, disydonols A-C (1-3), and one known compound (S)-(+)-sydonol (4) were isolated from the fermentation broth of a marine-derived fungus Aspergillus sp., which was isolated from the sponge Xestospongia testudinaria collected from the South China Sea. Their structures were elucidated on the basis of comprehensive spectral analysis including 1D and 2D NMR spectra and HR-ESI-MS. These compounds were evaluated for cytotoxic activity against HepG-2 and Caski human tumour cell lines. Among them, compounds 1 and 3 exhibited cytotoxicity against the two cell lines.     

Furanoflavonoid glycosides from Pongamia pinnata fruits

Pongamia pinnata fruits afforded three new furanoflavonoid glucosides, pongamosides A-C (1-3), and a new flavonol glucoside, pongamoside D (4). The structures of these compounds were established on the basis of spectroscopic studies. This is the first time that furanoflavone glucosides have been found as naturally occurring compounds.     

Cytotoxic dihydrobenzophenanthridine alkaloids from the roots of Macleaya microcarpa

Five dihydrobenzophenanthridine alkaloids, named as maclekarpine A-E, were isolated from the roots of Macleaya microcarpa, together with 10 known benzophenanthridine/dihydrobenzophenanthridine derivatives and a known amide. Their structures were determined on the basis of spectroscopic methods. The relative configuration of maclekarpine A was solved by X-ray single-crystal diffraction, which also contributed to the establishment of the relative configuration of maclekarpine B and C, as well as the assignment of the absolute configuration of maclekarpine A-C with aid of their CD curves. Cytotoxicity of the isolated compounds against five human tumor cell-lines was evaluated, with some having activity with IC₅₀ values ranging from 0.1 to 3.5 μM.     

Hydrazidomycins, cytotoxic alkylhydrazides from Streptomycesatratus

Three unusual alkyhydrazide natural products, named hydrazidomycin A (1), B (2) and C (3), were isolated from the chloroform extract of a Streptomycesatratus culture, and their structures were elucidated by MS and NMR techniques. Hydrazidomycins A-C exhibited moderate to strong cytotoxic activities in a panel of 42 cell lines, with hydrazidomycin A being the most potent compound (mean IC(50)=0.37 μM).     

Newbouldiosides A-C, phenylethanoid glycosides from the stem bark of Newbouldia laevis

From the stem bark of Newbouldia laevis three phenylethanoid glycosides, designated as newbouldioside A-C, were isolated together with a sodium salt of analogue B and the known compounds, verbascoside, 5-hydroxydehydro-iso-alpha-lapachone, 3,8-dihydroxydehydro-iso-alpha-lapachone, apigenin and luteolin. The structures of the phenylethanoid glycosides were elucidated by spectroscopic methods as beta-(3,4-dihydroxyphenyl)ethyl 5-O-syringoyl-beta-D-apiofuranosyloxy-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->3)]-beta-D-glucopyranoside, ss-(3,4-dihydroxyphenyl)ethyl 5-O-syringoyl-beta-D-apiofuranosyloxy-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->3)]-6-O-E-feruloyl-beta-D-glucopyranoside, and beta-(3,4-dihydroxyphenyl)ethyl 3-O-E-feruloyl-beta-D-apiofuranosyloxy-(1-->2)-O-alpha-L-rhamnopyranosyl-(1-->2)-6-O-E-sinapoyl-beta-D-glucopyranoside, respectively.     

New polyhydroxylated sterols stylisterols A-C and a novel 5,19-cyclosterol hatomasterol from the Okinawan marine sponge Stylissa sp

New polyhydroxylated sterols, stylisterol A-C (1-3), and a novel 5,19-cyclosterol, hatomasterol (4) were isolated from the Okinawan sponge Stylissa sp. Structural determinations of these compounds were made by spectroscopic analysis and chemical conversion. Assessment of cytotoxicity toward HeLa cells was also determined.     

Abietane diterpenoid dimers from the roots of Salvia prionitis

Three abietane diterpenoid dimers, bisprioterones A-C (1-3), were isolated from roots of the Chinese folk medicinal plant Salvia prionitis Hance (Labiatae). Compounds 1-3 possessed two different abietane diterpenoid skeleta, which were linked via either a C-C single bond (1 and 2) or an ether bridge (3). Their structures were elucidated by analysis of 1D and 2D NMR spectroscopic data. The structure of 1 was further confirmed by a single-crystal X-ray diffraction determination.     

neo-Clerodane diterpenoids from Scutellaria barbata with cytotoxic activities

Three neo-clerodane diterpenoids, named barbatins A-C (1-3), and the neo-clerodane diterpenoid nicotinyl ester, named scutebarbatine B (4), were isolated from the whole plant of Scutellaria barbata D. Don. Their structures were elucidated by spectroscopic analyses (UV, IR, HRFAB-MS, 1D NMR and 2D NMR). In vitro, compounds 1-4 showed significant cytotoxic activities against three human cancer lines, namely, HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells, with IC50 values in the range 3.5-8.1 microM.