Anthrasesamones from roots of Sesamum indicum

Three anthraquinones, named anthrasesamones A, B and C, were isolated from the roots of Sesamum indicum, and their respective structures were determined to be 1-hydroxy-2-(4-methylpent-3-enyl)anthraquinone, 1,4-dihydroxy-2-(4-methylpent-3-enyl)anthraquinone and 2-chloro-1,4-dihydroxy-3-(4-methylpent-3-enyl)anthraquinone on the basis of spectroscopic evidence. Two known anthraquinones were also isolated for the first time from S. indicum roots and characterized as 2-(4-methylpent-3-enyl)anthraquinone and (E)-2-(4-methylpenta-1,3-dienyl)anthraquinone. Anthrasesamone C is a rare chlorinated anthraquinone in higher plants.     

Anthrasesamones D and E from Sesamum indicum roots

Two anthraquinone derivatives, named anthrasesamones D and E, were isolated from the roots of Sesamum indicum. Their respective structures were determined to be 1,2,4-trihydroxy-3-(4-methylpent-3-enyl)anthraquinone and 1,2-dihydroxy-3-(4-methylpent-3-enyl)anthraquinone on the basis of spectroscopic evidence.     

Biosynthesis of anthraquinone derivatives in a Sesamum indicum hairy root culture

In order to investigate the intermediacy of 2-(4-methylpent-3-en-1-yl)anthraquinone (MPAQ), a possible intermediate for the biosynthesis of anthraquinone derivatives in sesame (Sesamum indicum), ²H-labeled MPAQ was administered to a hairy root culture of S. indicum. Efficient conversion of fed MPAQ to 2-[(Z)-4-methylpenta-1,3-dien-1-yl]anthraquinone ((Z)-MPDEAQ) was observed. Furthermore, administration experiment with ²H-labeled 2-geranyl-1,4-naphthohydroquinone, another possible intermediate, showed that it was converted to MPAQ and (Z)-MPDEAQ. The results clearly demonstrated that these substrates are the actual precursors for the production of (Z)-MPDEAQ. In contrast, neither MPAQ nor 2-geranyl-1,4-naphthohydroquinone was converted to anthrasesamone B and 2,3-epoxyanthrasesamone B, other anthraquinone derivatives in the hairy roots, suggesting that these substrates may not be the common precursors in the biosynthesis of anthraquinone derivatives.     

New chromenochalcones from Flemingia

2-Methyl-2-(4′-methylpent-3′-enyl)-5,8-dihydroxy-6-(4-hydroxycinnamoyl)-chromene (flemingin-D) has been isolated from inflorescences of Flemingia congesta, together with the known flemingin-C and two other chalcones. These (flemingin-E and -F) are allylic alcohols which differ from flemingin-D by an additional OH group in the side chain. Photooxidation of model 2-methyl-2-(4′-methylpent-3′-enyl)-chromenes gave pairs of allylic alcohols with the same structural feature. The known flemingin-A, -B, -C and homoflemingins have been isolated from F. grahamiana, and another new chalcone from F. bracteata.     

Bangangxanthone A and B, two xanthones from the stem bark of Garcinia polyantha Oliv

Two xanthones, bangangxanthone A (1) [1,5,8-trihydroxy-6'-methyl-6'-(4-methylpent-3-enyl)- pyrano[2',3':3,4]xanthone] and B (2) [1,4,8-trihydroxy-2-prenylxanthone], along with two known xanthones, 1,5-dihydroxyxanthone, 2-hydroxy-1,7-dimethoxyxanthone and the pentacyclic triterpenoids, friedelin, oleanolic acid and lupeol were isolated from the chloroform extract of the stem bark of Garcinia polyantha. The structures of these compounds were assigned by spectroscopic analysis. Compounds 1-4 showed antioxidant DPPH radical scavenging activities.     

Diterpenes from Laennecia sophiifolia

From the aerial parts of Laennecia sophiifolia (Kunth) G.L. Nesom, a neo-clerodane and an acyclic furano diterpene were isolated, along with four known compounds, 2beta-hydroxyhardwickiic acid, hawtriwaic acid, apigenin, and beta-sitosterol. Their structures were established as 12-epi-bacchotricuneatin A and (2E,6E)-9-(3-furyl)-6-methyl-2-(4-methylpent-3-enyl)-nona-2,6-dienoic acid, by analysis of spectral evidence. The absolute structure of 12-epi-bacchotricuneatin A was determined by a circular dichroism spectral comparison with that of bacchotricuneatin A.     

C(25) highly branched isoprenoid alkenes from the marine benthic diatom Pleurosigma strigosum

The hydrocarbon composition of the marine diatom Pleurosigma strigosum isolated from coastal Mediterranean sediments is described. A suite of five C(25) highly branched isoprenoid (HBI) alkenes with 2-5 double bonds were detected together with n-C(21:4) and n-C(21:5) alkenes and squalene. The analysis by (1)H and (13)C NMR spectroscopy of two isolated HBI alkenes allowed the structural identification of a novel C(25) HBI triene (2,6,10,14-tetramethyl-7-(3-methylpent-4-enyl)-pentadeca-5E,13-diene) and the first identification in diatom cells of 2,6,10,14-tetramethyl-7-(3-methylpent-4-enyl)-pentadec-5E-ene, an HBI previously detected in marine sediments and particulate matter. The other minor C(25) HBIs detected were a tetraene and a pentaene that have been previously identified in other diatoms from the genera Haslea and Rhizosolenia, and one other C(25) tetraene that could not be structurally identified. The structures of the HBI alkenes of P. strigosum were compared with those of C(25) homologues previously identified in three other Pleurosigma sp. (Pleurosigma intermedium, Pleurosigma planktonicum and Pleurosigma sp.). Unlike most structures previously reported, none of the HBI alkenes produced by P. strigosum showed an unsaturation at C7-C20, or E/Z isomerism of the trisubstituted double bond at C9-C10 (whenever present).     

Xanthones from Garcinia smeathmannii (Oliver) and their antimicrobial activity

Two new xanthones, smeathxanthone A (1) (2-(3,7-dimethyl-2,6-octadienyl)-1,3,5,8-tetrahydroxyxanthone) and smeathxanthone B (2) (5,7,10-trihydroxy-2-methyl-2-(4-methylpent-3-enyl)[2H, 6H]pyrano[3,2-b]xanthen-6-one), have been isolated from the stem bark of Garcinia smeathmannii, and their structures elucidated on the basis of 1D and 2D NMR experiments. 1,3,5-Trihydroxyxanthone and 1,5-dihydroxyxanthone were also obtained. The compounds showed only modest activity against a range of bacteria and yeasts.     

Prenylated flavonoids of Erythrina lysistemon grown in Egypt

Three prenylated flavonoid derivatives; 5,7,4′-trihydroxy-8-(3-methylbut-2-enyl)-6-(2″-hydroxy-3″-methylbut-3″enyl) isoflavone (isoerysenegalensein E), 5,7,2′-trihydroxy-4′-methoxy-5′-(3″-methylbut-2″-enyl) isoflavanone (lysisteisoflavanone), 5, 4′-dihydroxy-6-(3-methylbut-2-enyl)-2″-hydroxyisopropyl dihydrofurano [4″,5″:8,7] isoflavone (isosenegalensin), together with the four known flavonoids abyssinone V-4′-methylether, alpinumisoflavone, wighteone and burttinone were isolated from the stem bark of Erythrina lysistemon Hutch. (Leguminosae). Structures were elucidated by spectroscopic methods.     

Monoterpenoids from the aerial parts of Aruncus dioicus var. kamtschaticus and their antioxidant and cytotoxic activities

The aerial parts of Aruncus dioicus var. kamtschaticus afforded five new monoterpenoids (1-5): 4-(erythro-6,7-dihydroxy-9-methylpent-8-enyl)furan-2(5H)-one (1, aruncin A), 2-(8-ethoxy-8-methylpropylidene)-5-hydroxy-3,6-dihydro-2H-pyran-4-carboxylic acid (2, aruncin B), 4-(hydroxymethyl)-6-(8-methylprop-7-enyl)-5,6-dihydro-2H-pyran-2-one-11-O-β-d-glucopyranoside (3, aruncide A), (3S,4S,5R,10R)-3-(10-ethoxy-11-hydroxyethyl)-4-(5-hydroxy-7-methylbut-6-enyl)oxetan-2-one-11-O-β-d-glucopyranoside (4, aruncide B), and (3S,4S,5R,7R)-5-(9-methylprop-8-enyl)-1,6-dioxabicyclo[3,2,0]heptan-2-one-7-(hydroxymethyl)-12-O-β-d-glucopyranoside (5, aruncide C). Compound 2 showed potent cytotoxicity against Jurkat T cells with an IC₅₀ value of 17.15 μg/mL. In addition, compounds 7 and 10 exhibited moderate antioxidant activity with IC₅₀ values of 46.3 and 11.7 μM, respectively.     

Synthesis and Antimalarial Activity of Some New 1,2-Dioxolane Derivatives

The synthesis of 1,2-dioxolane derivatives in two different acetophenone series, as simplified models of natural coumarins is described. 2-Acetyl-3-acetoxy-4-(3-hydroperoxy-3-methylbut-1-enyl)phenyl acetate and 2-acetyl-5-acetoxy-4-(3-hydroperoxy-3-methylbut-1-enyl) phenyl acetate synthons are used as precursors to these structures. In vitro antimalarial activity of the 1,2-dioxolane derivatives has been investigated.     

A Facile Synthesis of cis-9-[4-(1,2-Dihydroxyethyl)-cyclopent-2-enyl]guanine and Its Derivative

Abstract

The synthesis of carbocyclic nucleosides, cis-9-[4-(1,2-dihydroxyethyl)-cyclopent-2-enyl]guanine (3) and cis-2-amino-6-cyclopropylamino-9-[4-(1,2-dihydroxyethyl)-cyclopent-2-enyl]guanine (4), was achieved from cyclopentadiene (5) in five and six steps, respectively. This route involves a hetero Diels-Alder reaction and a Pd(0)-catalyzed coupling reaction.     

Reactions of plant copper/topaquinone amine oxidases with N6-aminoalkyl derivatives of adenine

Plant copper/topaquinone-containing amine oxidases (CAOs, EC 1.4.3.6) are enzymes oxidising various amines. Here we report a study on the reactions of CAOs from grass pea (Lathyrus sativus), lentil (Lens esculenta) and Euphorbia characias, a Mediterranean shrub, with N⁶-aminoalkyl adenines representing combined analogues of cytokinins and polyamines. The following compounds were synthesised: N⁶-(3-aminopropyl)adenine, N⁶-(4-aminobutyl)adenine, N⁶-(4-amino-trans-but-2-enyl)adenine, N⁶-(4-amino-cis-but-2-enyl)adenine and N⁶-(4-aminobut-2-ynyl)adenine. From these, N⁶-(4-aminobutyl)adenine and N⁶-(4-amino-trans-but-2-enyl)adenine were found to be substrates for all three enzymes (K_m～10^?4?M). Absorption spectroscopy demonstrated such an interaction with the cofactor topaquinone, which is typical for common diamine substrates. However, only the former compound provided a regular reaction stoichiometry. Anaerobic absorption spectra of N⁶-(3-aminopropyl)adenine, N⁶-(4-amino-cis-but-2-enyl)adenine and N⁶-(4-aminobut-2-ynyl)adenine reactions revealed a similar kind of initial interaction, although the compounds finally inhibited the enzymes. Kinetic measurements allowed the determination of both inhibition type and strength; N⁶-(3-aminopropyl)adenine and N⁶-(4-amino-cis-but-2-enyl)adenine produced reversible inhibition (K_i～10^?5–10^?4?M) whereas, N⁶-(4-aminobut-2-ynyl)adenine could be considered a powerful inactivator.     

Anthrasesamone F from the Seeds of Black Sesamum indicum

A new anthraquinone derivative, named anthrasesamone F, was isolated from the seeds of Sesamum indicum. Its structure was determined to be (Z)-6,7-dihydroxy-2-(6-hydroxy-4-methyl-3-pentenyl)anthraquinone on the basis of spectroscopic evidence.     

Glycosylated nervogenic acid derivatives from Liparis condylobulbon (Reichb.f.) leaves

Three new nervogenic acid glycosides, 1-O-α-l-rhamnopyranosyl 3,5-bis(3-methyl-but-2-enyl)-4-O-[α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-benzoate, 3,5-bis(3-methyl-but-2-enyl)-4-O-[α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-benzoic acid, and bis{3,5-bis(3-methyl-but-2-enyl)-4-O-[α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-benzoyl} 1,2-O-β-d-glucopyranose, which we named condobulbosides A–C, were isolated from a methanol extract of the leaves of Liparis condylobulbon together with an apigenin C-glycoside, schaftoside. Their structures were established on the basis of spectral techniques, namely, UV, IR, HR-MS spectroscopy, both 1D and 2D NMR experiments, and chemical reactions.     

Effect of chloride ions on anthrasesamone C production in a Sesamum indicum hairy root culture and identification of the precursor for its abiotic formation

The content of anthrasesamone C (5), a rare chlorine-containing anthraquinone, in a hairy root culture of Sesamum indicum increased with increasing chloride ion concentration in the culture medium and reached a maximum at 100 mM. However, the amount of anthrasesamone C (5) in the extract obtained from the hairy roots was increased by incubating the extract. This result suggests that anthrasesamone C (5) was produced from an unidentified metabolite by an abiotic process. 2,3-Epoxyanthrasesamone B (1), a precursor for the non-enzymatic formation of anthrasesamone C (5), was isolated from S. indicum hairy roots cultured in a chloride-deficient medium. Its structure was elucidated to be 2,3-epoxy-9,10-dihydroxy-2-(4-methylpent-3-en-1-yl)-2,3-dihydroanthracene-1,4-dione by spectroscopic methods.     

Phenolic derivatives from Artemisia campestris subsp. Glutinosa

From the hexane extract of Artemisia campestris subsp. glutinosa, sakuranetin, dihydroquercetin-7,3′-dimethyl ether and three acetophenone derivatives identified as 3-[4-acetoxyisopent-2(Z)-enyl]-4-hydroxyacetophenone, 3-[4-acetoxyisopent-2(E)-enyl]-4-hydroxyacetophenone and 3-(3-acetoxymethyl-2-hydroxybut-3-enyl)-4-hydroxyacetophenone, have been isolated.     

Das Verhalten von CO2-Assimilation,Nadpund PGS-Reduktion und ATP-Synthese Intakter Blattzellen in Abhängigkeit vom Wassergehalt

Summary The carrot-root tissue culture assay for cytokinin activity has been improved by changing the site of explant excision and eliminating certain vitamins from the basal medium. These modifications increased its sensitivity and enabled zeatin [6-(4-hydroxy-3-methylbut-trans-2-enyl)aminopurine] to be detected at concentrations less than 5×10^-5M. In the improved assay, zeatin was markedly more active than kinetin, 6-benzylaminopurine, 6-(o-methylbenzyl)aminopurine and 6-(3-methylbut-2-enyl)aminopurine.The activity of zeatin also exceeded that of kinetin in the etiolated bean-leaf disk expansion assay. Zeatin was markedly more effective than kinetin and 6-(3-methylbut-2-enyl)aminopurine in promoting frond expansion and increasing frond number of Spirodela oligorrhiza cultures grown under continuous illumination. Zeatin was also more active than kinetin and 6-(3-methylbut-2-enyl)aminopurine in increasing frond number of Spirodela cultures grown in darkness. In retarding the senescence of disks of leaves of several species, kinetin was considerably more effective than zeatin which was more active than 6-(3-methylbut-2-enyl)aminopurine. The allylic hydroxyl group in zeatin is therefore a structural feature associated with high cytokinin activity.The relative activities of cytokinins can be very different and even in reverse order in different bioassays. It is suggested that this is due to the mechanism of cytokinin action varying in the different biological systems used.Part IV: Shannon and Letham (1966).     

Effects of 9,10-dihydroxy-4,4-dimethyl-5,8-dihydro-1(4H)-anthracenone derivatives on tumor cell respiration

A series of tricyclic hydroquinones, incorporating a carbonyl group in the ortho position relative to the phenol function, were tested as inhibitors of oxygen uptake against the TA3 mouse carcinoma cell line and its multidrug-resistant variant TA3-MTX-R. The title compound, which proved to be the most active one, also exhibited low micromolar dose-dependent growth inhibition of the human tumor U937 cell line (human monocytic leukemia). A tentative structure-activity relationship is proposed for these substances. A comparison between the cytotoxicities of the title compound and 4,4-dimethyl-5,8-dihydroxynaphthalene-1-one, with their activities as inhibitors of oxygen uptake by the TA3-MTX-R cell line, is presented. Also, the inhibition of oxygen uptake by 6-(4-methylpent-3-enyl)-1,4-naphthoquinone was determined and compared with its reported cytotoxicity toward P-388 (murine lymphocytic leukemia), A-549 (human lung carcinoma), HT-29 (human colon carcinoma), and MEL-28 (human melanoma) cells. The inhibition of oxygen uptake by TA3-MTX-R cells is useful as a quick test for preliminary screening of possible anticancer activity.     

Prenylated flavonoids of Erythrina lysistemon grown in Egypt

Three prenylated flavonoid derivatives; 5,7,4′-trihydroxy-8-(3-methylbut-2-enyl)-6-(2″-hydroxy-3″-methylbut-3″enyl) isoflavone (isoerysenegalensein E), 5,7,2′-trihydroxy-4′-methoxy-5′-(3″-methylbut-2″-enyl) isoflavanone (lysisteisoflavanone), 5, 4′-dihydroxy-6-(3-methylbut-2-enyl)-2″-hydroxyisopropyl dihydrofurano [4″,5″:8,7] isoflavone (isosenegalensin), together with the four known flavonoids abyssinone V-4′-methylether, alpinumisoflavone, wighteone and burttinone were isolated from the stem bark of Erythrina lysistemon Hutch. (Leguminosae). Structures were elucidated by spectroscopic methods.