Three acylated flavone glycosides from Sideritis ozturkii Aytac & Aksoy

From the aerial parts of Sideritis ozturkii, three new flavonoids, chrysoeriol 7-O-[2'-O-caffeoyl-O-acetyl-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside], chrysoeriol 7-O[2'-O-caffeoyl-beta-D-glucopyranosyl-(1 -->2)-beta-D-glucopyranoside] and chrysoeriol 7-O[2'-O-p-coumaroyl-6'-beta-O-acetyl-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside] named as ozturkosides A, B and C, respectively, were isolated, along with three known phenylethanoid glycosides, verbascoside, leucoseptoside A, martynoside and five known diterpenoids, 7-epicandicandiol, linearol, sidol, sideroxol, epoxyisolinearol. The structures were elucidated mainly by spectroscopic methods.     

The microbiological transformation of 7alpha-hydroxy-ent-kaur-16-ene derivatives by Gibberella fujikuroi

The biotransformation of 7alpha-hydroxy-ent-kaur-16-ene (epi-candol A) by the fungus Gibberella fujikuroi gave 7alpha,16alpha,17-trihydroxy-ent-kaur-16-ene and a seco-ring B derivative, fujenoic acid, whilst the incubation of candicandiol (7alpha,18-dihydroxy-ent-kaur-16-ene) and canditriol (7alpha,15alpha,18-trihydroxy-ent-kaur-16-ene) afforded 7alpha,18,19-trihydroxy-ent-kaur-16-ene and 7alpha,11beta,15alpha,18-tetrahydroxy-ent-kaur-16-ene, respectively. The presence of a 7alpha-hydroxyl group in epi-candol A avoids its biotransformation along the biosynthetic pathway of gibberellins, and directs it to the seco-ring B acids route. The 15alpha-hydroxyl group in canditriol inhibits oxidation at C-19 and direct hydroxylation at C-11(beta). The formation of fujenoic acid, from 7alpha-hydroxy-ent-kaur-16-ene, probably occurs via 7alpha-hydroxykaurenoic acid and 7-oxokaurenoic acid, with subsequent hydroxylation at the C-6(beta) position.     

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.     

Cytotoxic ent-kaurene diterpenoids from Isodon phyllostachys

ent-Kaurene diterpenoids, phyllostachysins D-H (1-5), together with nine known compounds, rabdoloxins A-B (6-7), rabdoinflexin B (8), amethystoidin A (9), rabdokunmin D (10), macrocalyxin E (11), 5,7-dihydroxy-4'-hydroxylflavone (12), oleanolic acid (13) and daucosterol (14), were isolated from aerial parts of Isodon phyllostachys. Structures were elucidated on the basis of spectroscopic methods, especially using 2D-NMR spectroscopic analyses. All ent-kaurenoids were tested for their cytotoxic effects against K562 cells. Compound 9 was the most potent with an IC50 value of 0.69 microg/ml.     

Four new labdane diterpene oxides from Sideritis gomerae

Four new labdane diterpene oxides gomeraidehyde, 13-epigomeraldehyde, gomeric acid and 13-epigomeric acid as well as eperu-13-ene-8β,15-diol were isolated from the aerial part of Sideritis gomerae.     

Diterpenoids from Isodon enanderianus

Four ent-kauranoids, 6-epiangustifolin and enanderinanins F-H, as well as 11 known ent-kaurane diterpenoids, macrocalin B, xerophilusin A, trichorabdal A, trichorabdal B, effusin, angustifolin, longikaurin D, longikaurin F, enanderinanin B, xerophilusin G and shikokianin were isolated from the aerial parts of Isodon enanderianus. The new diterpenoids were identified as 6-epiangustifolin (11alpha-hydroxy-6alpha-methoxy-6,19-epoxy-6,7-seco-ent-kaur-16-en-15-one-7,20-olide), enanderinanin F (19-acetoxy-6,20:6,11beta-diepoxy-6,7-seco-ent-kaur-16-en-15-one-1beta,7-olide), enanderinanin G (1beta,6beta,7beta-trihydroxy-19-acetoxy-16beta-methoxymethyl-7alpha,20-epoxy-ent-kaur-15-one) and enanderinanin H (6beta,7beta,14beta-trihydroxy-1alpha,11beta-acetonide-7alpha,20-epoxy-ent-kaur-16-en-15-one), respectively, on the basis of spectral data, especially by 2D NMR techniques. 6-Epiangustifolin showed significant cytotoxic activity against K562 cell.     

Cytotoxic ent-kaurane diterpenoids from Isodon sinuolata

Five (1–5) ent-kaurane diterpenoids and 17 other known ones, were isolated from the leaves and stems of Isodon sinuolata. Their structures were determined on the basis of spectroscopic methods including 1D and 2D NMR spectroscopic analysis. All compounds were evaluated for cytotoxicity against a small panel of cell lines. Some compounds exhibited significant cytotoxicity.     

ent-Beyerane diterpenoids from the heartwood of Excoecaria parvifolia

Chromatographic fractionations of the toluene extract of the heartwood of Excoecaria parvifolia collected in Australia resulted in the isolation of 12 beyerane diterpenes (1-12), and the triterpene, lupeol. Four of the isolated diterpenoids (5-7 and 12) have unusual structures: ent-3-oxa-beyer-15-en-2-one, (5); ent-15,16-epoxy-2-hydroxy-19-norbeyer-1,4-dien-3-one (6); methyl ent-2,4-seco-15,16-epoxy-4-oxo-3,19-dinorbeyer-15-en-2-oate (7); and ent-2,17-dihydroxy-19-norbeyer-1,4,15-trien-3-one (12). The structures were established by spectroscopic analyses, NMR data comparisons with similar diterpenes, and chemical correlations. All the diterpenes are assumed to have the same absolute configuration as the co-occurring (+)-stachenol (4). Diosphenol 2 and nor-lactone 5 exhibited significant potency in bioassays for cytotoxic activity against leukemia cells (L1210). Plausible biosynthetic pathways are proposed to explain the origin of the diterpene metabolites.     

Three ent-trachylobane diterpenes from the leaf exudates of Psiadia punctulata

Three ent-trachylobane diterpenes have been isolated from the leaf exudates of Psiadia punctulata and characterised as 6α,17,19-ent-trachylobantriol; 2α,18,19-ent-trachylobantriol; and 2β,6α,18,19-ent-trachylobantetraol. The structures were determined on the basis of spectroscopic evidence.     

ent-Abietane diterpenoids from Isodon rubescens var. rubescens

ent-Abietane diterpenoids, hebeiabinins A-F (1-5), together with seven known diterpenoids were isolated from leaves of Isodon rubescens var. rubescens. The structures of 1-5 were established on the basis of spectroscopic analyses, including application of 2D NMR spectroscopic techniques. The diterpenoids isolated were evaluated for the cytotoxicity against A549, HT-29, and K562 tumor cells. Compound 5 was the most active with IC(50) value of 0.91 microM against A549 cells.     

6-Methylcryptoacetalide, 6-methyl-epicryptoacetalide and 6-methylcryptotanshinone from Salvia aegyptiaca

From the whole plant of Salvia aegyptiaca, 6-methylcryptoacetalide, 6-methyl-epicryptoacetalide and 6-methylcryptotanshinone have been isolated and characterized, mainly by spectroscopic means. In addition to these novel diterpenoids, the known compounds 3beta-hydroxy-olean-12-en-28-oic acid, 3beta-hydroxy-oleana-11,13(18)-dien-28-oic acid, sitosterol-3beta-glucoside, sitosterol, stigmasterol, 5-hydroxy-7,3',4'-trimethoxyflavone and 5, 6-dihydroxy-7,3',4'-trimethoxyflavone were isolated.     

3-Methylbutanoyl and 3-methylbut-2-enoyl disaccharides from green coffee beans (Coffea arabica)

The aerial parts of Teucrium oliverianum yielded two neo-clerodane diterpenoids, teucrolin F and G, together with the known teucrolin E. The previously proposed structure for teucrolin E was revised so that it contains a tetrahydrofuran ring instead of an oxetane ring. This was based on analysis of the NMR spectroscopic data of its diacetate, including its NOE spectra. In addition, the structural assignments of the new diterpenoids were based on 1H and 13C NMR spectroscopic studies, mainly 2D NMR experiments, including homonuclear and heteronuclear correlations.     

ent-Verticillane-type diterpenoids from the Japanese liverwort Jackiella javanica

Three ent-verticillane diterpenoids and two ent-sesquiterpenoids were isolated from the Japanese liverwort Jackiella javanica Schiffn. together with five known ent-verticillane and three ent-kaurane diterpenoids, and three sesquiterpenoids. Five ent-verticillane epoxides were synthetically prepared from ent-verticillols action to clarify the absolute configuration of natural ent-9,10-epoxyverticillol. Their structures were established by extensive NMR spectroscopic and X-ray crystallographic analyses.     

Ingenane diterpenoids from Euphorbia esula

An extensive study of metabolites present in Euphorbia esula led to isolation of 16 ingenane diterpenoids 1-16 together with the known ingenane derivative 17 and four known cycloartane triterpenoids. Their structures were elucidated on the basis of spectroscopic studies and comparison with known related compounds. All the compounds were assayed for their inhibitory activity against human HeLa cervical cancer cell line.     

Steroid hydroxylations with Botryodiplodia malorum and Colletotrichum lini

An improved procedure for the microbial hydroxylations of dehydroepiandrosterone (DHEA, 1) and 15 beta,16 beta-methylene-dehydroepiandrosterone (2) was studied using whole cells of Botryodiplodia malorum and Colletotrichum lini. C. lini catalyzed 7 alpha- and 15 alpha-hydroxylation of 1 and 7 alpha-hydroxylation of 2, while B. malorum gave 7 beta-hydroxylation of both the substrates. The stability of the enzymatic activity was higher in the presence of co-substrates (i.e., glucose or mannitol) allowing for repeated batches of the biotransformations. The yields of 7 alpha,15 alpha-dihydroxy-1 production were improved obtaining 5.8 gl(-1) (recovered product) from 7.0 gl(-1) of substrate. The structures of the hydroxylated products were assigned by a combination of two-dimensional NMR proton-proton and proton-carbon correlation techniques.     

Ent-pimarane type diterpenes from Gnaphalium gaudichaudianum

Fractionation of the methanol extract of Gnaphalium gaudichaudianum DC afforded one new and six known ent-pimarane diterpenes together with velutin, squalene and stigmasterol. The structure of the new compound was established on the basis of extensive 1D and 2D NMR spectroscopic data interpretation. Two of the isolated compounds exhibited moderate toxicity in the Artemia salina toxicity test.     

Biotransformations of ent-18-acetoxy-6-ketomanoyl oxides epimers at C-13 with filamentous fungi

Two ent-18-acetoxy-6-oxomanoyl oxides, epimers at C-13, have been prepared from ent-6alpha,8alpha,18-trihydroxylabda-13(16),14-diene (andalusol), isolated from Sideritis foetens, by means of several chemical pathways and a regioselective acylation with Candida cylindracea lipase (CCL). Biotransformation of these 13-epimeric ent-manoyl oxides by Fusarium moniliforme and Neurospora crassa produced mainly ent-1beta- or ent-11alpha-hydroxylations, as well as their deacetylated derivatives, in both epimers. In addition, with the 13-epi substrate N. crassa originated other minor hydroxylations by the ent-alpha face at C-1 or at C-12, whereas an ent-11beta-hydroxyl group, probably originated by reduction of an 11-oxo derivative also isolated, was achieved with the 13-normal substrate.     

Diterpenoids and triterpenoids from Euphorbia guyoniana

Two new compounds with tigliane and cycloartane skeletons: 4,12-dideoxy(4alpha)phorbol-13-hexadecanoate (1) and 24-methylenecycloartane-3,28-diol (2), respectively, in addition of four known diterpenoids and 13 triterpenoids: 3-benzoyloxy-5,15-diacetoxy-9,14-dioxojatropha-6(17),11-diene (4), ent-abieta-8(14),13(15)-dien-16,12-olide (5), ent-8alpha,14alpha-epoxyabieta-11,13(15)-dien-16,12-olide (6), ent-3-hydroxyatis-16(17)-ene-2,14-dione (7), 3beta-hydroxytaraxer-14-en-28-oic acid (8), beta-sitosteryl-3beta-glucopyranoside-6'-O-palmitate (9), multiflorenyl acetate (10), multiflorenyl palmitate (11), peplusol (12), 24-methylenecycloartanol (3), lanosterol (13), euferol (14), butyrospermol (15), cycloartenol (16), obtusifoliol (17), cycloeucalenol (18) and beta-sitosterol (19), were isolated from the roots of Euphorbia guyoniana. Their structures were established on the basis of physical and spectroscopic analysis, including 1D and 2D homo- and heteronuclear NMR experiments (COSY, HSQC, HMBC and NOESY) and by comparison with the literature data.