Phytochemistry (v.138, #C)
Outside Front Cover (OFC).
Graphical Contents List (1-6).
Separation of phytochemicals from Helichrysum italicum: An analysis of different isolation techniques and biological activity of prepared extracts by Svetolik Maksimovic; Vanja Tadic; Dejan Skala; Irena Zizovic (9-28).
Helichrysum italicum presents a valuable source of natural bioactive compounds. In this work, a literature review of terpenes, phenolic compounds, and other less common phytochemicals from H. italicum with regard to application of different separation methods is presented. Data including extraction/separation methods and experimental conditions applied, obtained yields, number of identified compounds, content of different compound groups, and analytical techniques applied are shown as corresponding tables. Numerous biological activities of both isolates and individual compounds are emphasized. In addition, the data reported are discussed, and the directions for further investigations are proposed.With the growing interest in natural products, this review critically summarizes the results of investigations on the phytochemistry of isolates of Helichrysum italicum obtained by different extraction methods. Both extracts and individual compounds possess a variety of biological activities.Display Omitted
Keywords: Helichrysum italicum; Asteraceae; Terpenes; Phenolic compounds; Distillation; Supercritical CO2 extraction; Extraction by organic solvents; Biological activity;
The proteolytic system of pineapple stems revisited: Purification and characterization of multiple catalytically active forms by André Matagne; Laetitia Bolle; Rachida El Mahyaoui; Danielle Baeyens-Volant; Mohamed Azarkan (29-51).
Crude pineapple proteases extract (aka stem bromelain; EC 188.8.131.52) is an important proteolytic mixture that contains enzymes belonging to the cysteine proteases of the papain family. Numerous studies have been reported aiming at the fractionation and characterization of the many molecular species present in the extract, but more efforts are still required to obtain sufficient quantities of the various purified protease forms for detailed physicochemical, enzymatic and structural characterization. In this work, we describe an efficient strategy towards the purification of at least eight enzymatic forms. Thus, following rapid fractionation on a SP-Sepharose FF column, two sub-populations with proteolytic activity were obtained: the unbound (termed acidic) and bound (termed basic) bromelain fractions. Following reversible modification with monomethoxypolyethylene glycol (mPEG), both fractions were further separated on Q-Sepharose FF and SP-Sepharose FF, respectively. This procedure yielded highly purified molecular species, all titrating ca. 1 mol of thiol group per mole of enzyme, with distinct biochemical properties.N-terminal sequencing allowed identifying at least eight forms with proteolytic activity. The basic fraction contained previously identified species, i.e. basic bromelain forms 1 and 2, ananain forms 1 and 2, and comosain (MEROPS identifier: C01.027). Furthermore, a new proteolytic species, showing similarities with basic bomelain forms 1 and 2, was discovered and termed bromelain form 3. The two remaining species were found in the acidic bromelain fraction and were arbitrarily named acidic bromelain forms 1 and 2. Both, acidic bromelain forms 1, 2 and basic bromelain forms 1, 2 and 3 are glycosylated, while ananain forms 1 and 2, and comosain are not.The eight protease forms display different amidase activities against the various substrates tested, namely small synthetic chromogenic compounds (DL-BAPNA and Boc-Ala-Ala-Gly-pNA), fluorogenic compounds (like Boc-Gln-Ala-Arg-AMC, Z-Arg-Arg-AMC and Z-Phe-Arg-AMC), and proteins (azocasein and azoalbumin), suggesting a specific organization of their catalytic residues. All forms are completely inhibited by specific cysteine and cysteine/serine protease inhibitors, but not by specific serine and aspartic protease inhibitors, with the sole exception of pepstatin A that significantly affects acidic bromelain forms 1 and 2. For all eight protease forms, inhibition is also observed with 1,10-phenanthrolin, a metalloprotease inhibitor. Metal ions (i.e. Mn2+, Mg2+ and Ca2+) showed various effects depending on the protease under consideration, but all of them are totally inhibited in the presence of Zn2+.Mass spectrometry analyses revealed that all forms have a molecular mass of ca. 24 kDa, which is characteristic of enzymes belonging to the papain-like proteases family. Far-UV CD spectra analysis further supported this analysis. Interestingly, secondary structure calculation proves to be highly reproducible for all cysteine proteases of the papain family tested so far (this work; see also Azarkan et al., 2011; Baeyens-Volant et al., 2015) and thus can be used as a test for rapid identification of the classical papain fold.Eight cysteine peptidases were isolated from A. comosus stems, including a novel protease, by covalent grafting of a specific and reversible thiol-pegylation reagent. Mass spectroscopy and Far-UV CD analyses revealed very close molecular masses and secondary structure contents. Enzymatic activity measurements using different Fluorophore and chromophore substrates as well as protein substrates clearly demonstrated different substate specificities and allowed to clearly distinguish three different proteases populations.Display Omitted
Keywords: cysteine protease; Ananas comosus; Pineapple stems; Bromelain; Ananain; Comosain; Thiol-pegylation; Circular dichroism; Mass spectrometry;
Two residues determine the product profile of the class II diterpene synthases TPS14 and TPS21 of Tripterygium wilfordii by Nikolaj L. Hansen; Jakob N. Nissen; Björn Hamberger (52-56).
The medicinal plant Tripterygium wilfordii (Celastraceae) contains a pair of class II diterpene synthases (diTPS) of specialized labdane-type metabolism that, despite remarkably close homology, form strikingly different products. TwTPS21 catalyzes bicyclization of the linear C20 precursor geranylgeranyl diphosphate to ent-copal-8-ol diphosphate, while TwTPS14 forms kolavenyl diphosphate. To determine the amino acid signature controlling the functional divergence of the homologues, we modeled their structures based on an existing crystal structure of the Arabidopsis ent-copalyl diphosphate synthase, archetypal of diTPSs in general metabolism of gibberellin phytohormones. Of the residues differing between TwTPS21 and TwTPS14 two located to the predicted active site, and we hypothesized that these are responsible for the functional differentiation of the enzymes. Using site-directed mutagenesis, we generated a panel of six variants, where one, or both positions were exchanged between the enzymes. In coupled heterologous assays with a corresponding class I diTPS, TwTPS2, complete product interchange was observed in variants with both reciprocal mutations, while substitutions of either residue gave mixed product profiles. Two mutants, TwTPS14:Y265H and TwTPS21:A325V, also produced ent-copalyl diphosphate, highlighting the evolutionary potential of enzymes of this family to drive rapid diversification of plant diterpene biosynthesis through neo-functionalization. Our study contributes to the understanding of structure-function relation in plant class II diTPSs and complements previous mutational studies of Arabidopsis ent-copalyl diphosphate synthase with additional examples from the specialized metabolism of T. wilfordii.Display Omitted
Keywords: Tripterygium wilfordii; Celastraceae; Diterpene synthase; Homology model; Structure-function relation;
Metal ions and phosphatidylinositol 4,5-bisphosphate as interacting effectors of α-type plant phospholipase D by Lars Dreßler; Florian Michel; Iris Thondorf; Johanna Mansfeld; Ralph Golbik; Renate Ulbrich-Hofmann (57-64).
Plant phospholipases D (PLD) are typically characterized by a C2 domain with at least two Ca2+ binding sites. In vitro, the predominantly expressed α-type PLDs need 20–100 mM CaCl2 for optimum activity, whereas the essential activator of β- or γ-type PLDs, phosphatidylinositol 4,5-bisphosphate (PIP2), plays a secondary role. In the present paper, we have studied the interplay between PIP2 and metal ion activation of the well-known α-type PLD from cabbage (PLDα). With mixed micelles containing phosphatidyl-p-nitrophenol as substrate, PIP2-concentrations in the nanomolar range are able to activate the enzyme in addition to the essential Ca2+ activation. Mg2+ ions are able to replace Ca2+ ions but they do not activate PLDα. Rather, they abolish the activation of the enzyme by Ca2+ ions in the absence, but not in the presence, of PIP2. The presence of PIP2 causes a shift in the pH optimum of PLDα activity to the acidic range. Employing fluorescence measurements and replacing Ca2+ by Tb3+ ions, confirmed the presence of two metal ion-binding sites, in which the one of lower affinity proved crucial for PLD activation.Moreover, we have generated a homology model of the C2 domain of this enzyme, which was used for Molecular Dynamics (MD) simulations and docking studies. As is common for C2 domains, it shows two antiparallel β-sheets consisting of four β-strands each and loop regions that harbor two Ca2+ binding sites. Based on the findings of the MD simulation, one of the bound Ca2+ ions is coordinated by five amino acid residues. The second Ca2+ ion induces a loop movement upon its binding to three amino acid residues. Docking studies with PIP2 reveal, in addition to the previously postulated PIP2-binding site in the middle of the β-sheet structure, another PIP2-binding site near the two Ca2+ ions, which is in accordance with the experimental interplay of PIP2, Ca2+ and Mg2+ ions.The interplay of PIP2 and metal ions in the activation of α-type phospholipase D from cabbage is highlighted by Molecular Dynamics simulations.Display Omitted
Keywords: Brassica oleracea convar. capitata var. alba L.; Brassicaceae; Phospholipase D; C2 domain; Homology modelling; Molecular docking; Fluorescence; Activity; Calcium; PIP2; Mixed micelles;
Isolation and characterization of 9-lipoxygenase and epoxide hydrolase 2 genes: Insight into lactone biosynthesis in mango fruit (Mangifera indica L.) by Ashish B. Deshpande; Hemangi G. Chidley; Pranjali S. Oak; Keshav H. Pujari; Ashok P. Giri; Vidya S. Gupta (65-75).
Uniqueness and diversity of mango flavour across various cultivars are well known. Among various flavour metabolites lactones form an important class of aroma volatiles in certain mango varieties due to their ripening specific appearance and lower odour detection threshold. In spite of their biological and biochemical importance, lactone biosynthetic pathway in plants remains elusive. Present study encompasses quantitative real-time analysis of 9-lipoxygenase (Mi9LOX), epoxide hydrolase 2 (MiEH2), peroxygenase, hydroperoxide lyase and acyl-CoA-oxidase genes during various developmental and ripening stages in fruit of Alphonso, Pairi and Kent cultivars with high, low and no lactone content and explains their variable lactone content. Study also covers isolation, recombinant protein characterization and transient over-expression of Mi9LOX and MiEH2 genes in mango fruits. Recombinant Mi9LOX utilized linoleic and linolenic acids, while MiEH2 utilized aromatic and fatty acid epoxides as their respective substrates depicting their role in fatty acid metabolism. Significant increase in concentration of δ-valerolactone and δ-decalactone upon Mi9LOX over-expression and that of δ-valerolactone, γ-hexalactone and δ-hexalactone upon MiEH2 over-expression further suggested probable involvement of these genes in lactone biosynthesis in mango.Expression profiles of 9-lipoxygenase, epoxide hydrolase 2, peroxygenase, hydroperoxide lyase and acyl-CoA-oxidase genes were studied during various fruit developmental and ripening stages of Alphonso, Pairi and Kent cultivars and probable lactone biosynthesis pathway in mango is proposed. Isolation and functional characterization of genes encoding 9-lipoxygenase and epoxide hydrolase 2 was carried out and their probable role in the biosynthesis of lactones was investigated.Display Omitted
Keywords: Mangifera indica; Anacardiaceae; Lactone biosynthesis; Transient expression; 9-Lipoxygenase; Epoxide hydrolase 2;
A multidrug and toxic compound extrusion transporter mediates berberine accumulation into vacuoles in Coptis japonica by Kojiro Takanashi; Yasuyuki Yamada; Takayuki Sasaki; Yoko Yamamoto; Fumihiko Sato; Kazufumi Yazaki (76-82).
Plants produce a large variety of alkaloids, which have diverse chemical structures and biological activities. Many of these alkaloids accumulate in vacuoles. Although some membrane proteins on tonoplasts have been identified as alkaloid uptake transporters, few have been characterized to date, and relatively little is known about the mechanisms underlying alkaloid transport and accumulation in plant cells. Berberine is a model alkaloid. Although all genes involved in berberine biosynthesis, as well as the master regulator, have been identified, the gene responsible for the final accumulation of berberine at tonoplasts has not been determined. This study showed that a multidrug and toxic compound extrusion protein 1 (CjMATE1) may act as a berberine transporter in cultured Coptis japonica cells. CjMATE1 was found to localize at tonoplasts in C. japonica cells and, in intact plants, to be expressed preferentially in rhizomes, the site of abundant berberine accumulation. Cellular transport analysis using a yeast expression system showed that CjMATE1 could transport berberine. Expression analysis showed that RNAi suppression of CjbHLH1, a master transcription factor of the berberine biosynthetic pathway, markedly reduced the expression of CjMATE1 in a manner similar to the suppression of berberine biosynthetic genes. These results strongly suggest that CjMATE1 is the transporter that mediates berberine accumulation in vacuoles.The Coptis japonica MATE transporter 1 (CjMATE1) mediates berberine uptake into the vacuole, the last step of the berberine dynamics of C. japonica cultured cells.Display Omitted
Keywords: Coptis japonica; Ranunculaceae; Transport; Alkaloid; Berberine; CjMATE1;
3-Acyl dihydroflavonols from poplar resins collected by honey bees are active against the bee pathogens Paenibacillus larvae and Ascosphaera apis by Michael B. Wilson; Alison D. Pawlus; Doug Brinkman; Gary Gardner; Adrian D. Hegeman; Marla Spivak; Jerry D. Cohen (83-92).
Honey bees, Apis mellifera, collect antimicrobial plant resins from the environment and deposit them in their nests as propolis. This behavior is of practical concern to beekeepers since the presence of propolis in the hive has a variety of benefits, including the suppression of disease symptoms. To connect the benefits that bees derive from propolis with particular resinous plants, we determined the identity and botanical origin of propolis compounds active against bee pathogens using bioassay-guided fractionation against the bacterium Paenibacillus larvae, the causative agent of American foulbrood. Eleven dihydroflavonols were isolated from propolis collected in Fallon, NV, including pinobanksin-3-octanoate. This hitherto unknown derivative and five other 3-acyl-dihydroflavonols showed inhibitory activity against both P. larvae (IC50 = 17–68 μM) and Ascosphaera apis (IC50 = 8–23 μM), the fungal agent of chalkbrood. A structure-activity relationship between acyl group size and antimicrobial activity was found, with longer acyl groups increasing activity against P. larvae and shorter acyl groups increasing activity against A. apis. Finally, it was determined that the isolated 3-acyl-dihydroflavonols originated from Populus fremontii, and further analysis showed these compounds can also be found in other North American Populus spp.This work investigates the identity and botanical sources of propolis compounds important to bee health in North America. Six 3-acyl dihydroflavonols from Populus fremontii with differential activity against Ascosphera apis and Paenibacillus larvae were isolated from Fallon, NV, propolis. Further analysis showed these compounds have a variable distribution among other North American poplar species.Display Omitted
Keywords: Populus; Salicaceae; Honey bees (Apis mellifera); Paenibacillus larvae; Ascospharea apis; Plant resins; Antimicrobial activity; Dihydroflavonol; Propolis;
The effect of structurally related metabolites on insect herbivores: A case study on pyrrolizidine alkaloids and western flower thrips by Xiaojie Liu; Peter G.L. Klinkhamer; Klaas Vrieling (93-103).
Plant specialised metabolites (SMs) are very diverse in terms of both their number and chemical structures with more than 200,000 estimated compounds. This chemical diversity occurs not only among different groups of compounds but also within the groups themselves. In the context of plant-insect interactions, the chemical diversity within a class of structurally related metabolites is generally also related to their bioactivity. In this study, we tested firstly whether individual SMs within the group of pyrrolizidine alkaloids (PAs) differ in their effects on insect herbivores (western flower thrips, Frankliniella occidentalis). Secondly, we tested combinations of PA N-oxides to determine whether they are more active than their individual components. We also evaluated the bioactivity of six PA free bases and their corresponding N-oxides. At concentrations similar to that in plants, several PAs reduced thrip's survival but the effect also differed strongly among PAs. In general, PA free bases caused a lower survival than their corresponding N-oxides. Among the tested PA free bases, we found jacobine and retrorsine to be the most active against second instar larvae of thrips, followed by erucifoline and seneciphylline, while senecionine and monocrotaline did not exhibit significant dose-dependent effects on thrip's survival. In the case of PA N-oxides, we found that only senecionine N-oxide and jacobine N-oxide reduced thrip's survival, although the effect of senecionine N-oxide was weak. Combinations of PA N-oxides showed no synergistic effects. These findings indicate the differences observed in the effect of structurally related SMs on insect herbivores. It is of limited value to study the bioactivity of combined groups, such as PAs, without taking their composition into account.Pyrrolizidine alkaloids from Jacobaea vulgaris vary in their effect on thrips survival and combinations of PA N-oxides did not show synergistic effects.Display Omitted
Keywords: Jacobaea vulgaris; Asteraceae; Senecio spp.; Specialised metabolites; Plant defence; Chemical structure; Frankliniella occidentalis;
Diel rhythms in the volatile emission of apple and grape foliage by Valentino Giacomuzzi; Luca Cappellin; Stefano Nones; Iuliia Khomenko; Franco Biasioli; Alan L. Knight; Sergio Angeli (104-115).
This study investigated the diel emission of volatile organic compounds (VOCs) from intact apple (Malus x domestica Borkh., cv. Golden Delicious) and grape (Vitis vinifera L., cv. Pinot Noir) foliage. Volatiles were monitored continuously for 48 h by proton transfer reaction - time of flight - mass spectrometry (PTR-ToF-MS). In addition, volatiles were collected by closed-loop-stripping-analysis (CLSA) and characterized by gas chromatography-mass spectrometry (GC-MS) after 1 h and again 24 and 48 h later. Fourteen and ten volatiles were characterized by GC-MS in apple and grape, respectively. The majority of these were terpenes, followed by green leaf volatiles, and aromatic compounds. The PTR-ToF-MS identified 10 additional compounds and established their diel emission rhythms. The most abundant volatiles displaying a diel rhythm included methanol and dimethyl sulfide in both plants, acetone in grape, and mono-, homo- and sesquiterpenes in apple. The majority of volatiles were released from both plants during the photophase; whereas methanol, CO2, methyl-butenol and benzeneacetaldehyde were released at significantly higher levels during the scotophase. Acetaldehyde, ethanol, and some green leaf volatiles showed distinct emission bursts in both plants following the daily light switch-off. These new results obtained with a combined analytical approach broaden our understanding of the rhythms of constitutive volatile release from two important horticultural crops. In particular, diel emission of sulfur and nitrogen-containing volatiles are reported here for the first time in these two crops.Intact apple and grape foliage showed distinct diel rhythms in the release of volatile organic compounds. The use of proton transfer reaction - time of flight - mass spectrometry (PTR-ToF-MS) together revealed several new aspects of these plants' rhythmic release of volatiles.Display Omitted
Keywords: Malus x domestica, Rosaceae; Vitis vinifera, Vitaceae; CLSA-GC-MS; PTR-ToF-MS; Constitutive volatiles; Methanol; Acetaldehyde; (Z)-3-hexenyl acetate; ( E,E)-α-farnesene;
Artefact formation during acid hydrolysis of saponins from Medicago spp. by Aldo Tava; Elisa Biazzi; Mariella Mella; Paolo Quadrelli; Pinarosa Avato (116-127).
Artefact compounds obtained during acid hydrolysis of saponins from Medicago spp. (Fabaceae), have been monitored and evaluated by GC-FID. Their identification has been performed by GC-MS and 1H and 13C NMR. Saponins with different substituents on the triterpenic pentacyclic aglycones were considered, and their hydrolysis products were detected and quantified during 10 h of time course reaction. From soyasapogenol B glycoside the well known soyasapogenols B, C, D and F were obtained together with a previously undescribed sapogenol artefact identified as 3β,22β,24-trihydroxyolean-18(19)-en and named soyasapogenol H. From a zanhic acid saponin two major artefact compounds identified as 2β,3β,16α-trihydroxyolean-13(18)-en-23,28-dioic acid and 2β,3β,16α-trihydroxyolean-28,13β-olide-23-oic acid were obtained, together with some zanhic acid. Other compounds, detected in very small amount in the reaction mixture, were also tentatively identified based on their GC-MS and UV spectra. The other most characteristic saponins in Medicago spp., hederagenin, bayogenin and medicagenic acid glycosides, under acidic condition of hydrolysis, released instead the correspondent aglycones and generated a negligible amount of artefacts. Nature of artefacts and mechanism of their formation, involving a stable tertiary carbocation, is here proposed and discussed for the first time.Saponins from Medicago spp. with different substituents on the aglycone moieties were subjected to acid hydrolysis and several sapogenol artefacts were identified. A transposition of the double bond on the triterpenic structure and the formation of the corresponding -olide derivatives have been described.Display Omitted
Keywords: Medicago spp.; Fabaceae; Triterpenic pentacyclic saponins; Acid hydrolysis; Artefact formation; Chemical structure; Soyasapogenol H; GC-MS; NMR;
Hepatoprotective hemiterpene glycosides from the rhizome of Cibotium barometz (L.) J. Sm by Mei-Ping Xie; Lan Li; Hua Sun; An-Qi Lu; Bo Zhang; Jian-Gong Shi; Dan Zhang; Su-Juan Wang (128-133).
Five previously undescribed hemiterpene glycosides, cibotiumbarosides E−I, and two known hemiterpene glucosides, were isolated from the rhizome of Cibotium barometz (L.) J. Sm. The structures of cibotiumbarosides E−I were established by 1D and 2D NMR spectroscopic analyses and HRMS. The absolute configuration of the aglycone of cibotiumbaroside E was assigned by calculated ECD with the TDDFT method. Cibotiumbarosides F and I both exhibited remarkable hepatoprotective activity against APAP-induced acute liver damage in vitro, which were more effective than the positive control, bicyclol. On the other hand, seven hemiterpene glycosides were all inactive in assays of cytotoxicity, neuroprotection, antidiabetes and anti-inflammation.Five previously undescribed hemiterpene glycosides, cibotiumbarosides E−I, along with two known were isolated from the rhizome of Cibotium barometz (L.) J. Sm. Cibotiumbarosides F and I both exhibited remarkable hepatoprotective activity against APAP-induced acute liver damage in vitro, which is more effective than the positive control, bicyclol.Display Omitted
Keywords: Cibotium barometz (L.) J. Sm.; Dicksoniaceae; Hemiterpene glycosides; Hepatoprotection;
Dammarane-type saponins from leaves of Ziziphus spina-christi by Alen Bozicevic; Maria De Mieri; Angela Di Benedetto; Frank Gafner; Matthias Hamburger (134-144).
Phytochemical profiling of Ziziphus spina-christi leaves led to the characterization of 10 dammarane-type saponins and 12 phenolic compounds. Isolation was achieved by gel chromatography on Sephadex LH20, open column chromatography on silica gel, and semi-preparative HPLC with PDA and ELSD detectors. Structural characterization was performed by extensive 1D and 2D NMR, mass spectrometry, and by GC-MS of sugar derivatives. A biosynthetic pathway leading to three previously undescribed sapogenins is proposed. The saponin profiles in Z. spina-christi leaves of four different origins were compared by means of HPLC-ESIMS.Phytochemical profiling of Ziziphus spina-christi leaves afforded 10 saponins. Saponins 8–10 contained unprecedented dammarane-type aglycons. A plausible biogenetic pathway leading from the aglycons in 8 and 9 to that in 10 was proposed.Display Omitted
Keywords: Ziziphus spina-christi; Rhamnaceae; Dammarane saponins; Lotogenin; LC-MS;
Phytotoxic phenylpropanoids isolated from Ophryosporus charua (Griseb.) Hieron. by Margarita M. del M. Bravetti; Raquel V. Vico; Maria C. Carpinella; Carlos C. Ferrayoli; Sara M. Palacios (145-151).
Bioguided isolation of the EtOH extract from the medicinal native plant, Ophryosporus charua, against Raphanus sativus, yielded three phenylpropanoids, charuol A [(Z)-4-((1S,2R)-3-acetoxy-1,2-dihydroxypropyl)phenyl) 2-methylbut-2-enoate], charuepoxide [(Z)-4-((2S,3R)-3-(acetoxymethyl oxiran-2-yl)phenyl) 2-methylbut-2-enoate] and charuol B [(Z)-4-((1R,2R)-3-acetoxy-1,2-dihydroxypropyl)phenyl) 2-methylbut-2-enoate]. Their structures and absolute configuration were established by extensive spectroscopic analyses. The effective concentrations for 50% inhibition of germination (ECg50) and root (ECr50) and shoot (ECs50) elongations were determined for these compounds against P. miliaceum (monocot) and Raphanus sativus (dicot). Charuol A was the most active in the inhibition of germination of P. miliaceum (ECg50 = 0.97 mM), followed by charuol B and charuepoxide, although charuol B was the most effective in regulating the root growth of P. miliaceum seedlings, with an ECr50 of 1.0 mM. Charuol A inhibited the germination of R. sativus, while its seedling development was also affected by all three compounds with different effectiveness. Charuol A was also highly effective in the 0.09–0.30 mM range against other test species such as Lactuca sativa, Eruca sativa, Allium ampeloprasum and Secale cereale. Bioguided isolation of the EtOH extract from Ophryosporus charua, against the germination of Raphanus sativus seeds, yielded three phenylpropanoids, charuol A (1), charuepoxide (2) and charuol B (3). These compounds inhibited the germination and seedling development of different mono- and dicotyledonous species with different effectiveness.Display Omitted
Keywords: Ophryosporus charua; Asteraceae; Phenylpropanoids; Germination inhibition; Growth inhibition; Panicum miliaceum; Raphanus sativus; Lactuca sativa;
14,15-Secopregnane-type C21-steriosides from the roots of Cynanchum stauntonii by Jin-Qian Yu; Ming-Bao Lin; An-Jun Deng; Qi Hou; Jin-Ye Bai; Zhi-Hong Li; Lin Ma; Zhi-Hui Zhang; Shao-Peng Yuan; Ren-Tao Jiang; Hai-Lin Qin (152-162).
Nine 14,15-secopregnane-type C21-steriosides, stauntosides U, V, V1-V3, W and C1-C3, as well as two known C21-steriosides, were isolated from the roots of Cynanchum stauntonii. Stauntosides U, V and V1-V3 share the same basic structural features of 8α:14α,14:16,15:20,18:20-tetraepoxy-14,15-secopregn-6-ene-3β,5α,9α-triol, with the numbering system following that of C21-pregnanes. The aglycones of stauntosides U, V and V1-V3 are classified into two subcategories, the 5,9-dihydroxy groups and 5α:9α-peroxy bridge, according to the oxidative states of the two hydroxy groups at the C-5 and C-9 positions. The anti-inflammatory activity of the major compounds was assessed in an in vitro inflammatory model of mouse peritoneal macrophages using IC50 values of the inhibition of nitric oxide (NO) production as an indicator. Stauntosides V1 and V3 exhibited target activity with IC50 values of 9.3 μM and 12.4 μM, respectively, compared with dexamethasone, which was used as a positive control.IC50 of anti-inflammatory activies: stauntoside V1 12.4 μM; stauntoside V3 9.3 μM.Display Omitted
Keywords: Cynanchum stauntonii; Asclepiadaceae; 14,15-Secopregnane-type C21-steriosides; Stauntogenins E and F; Stauntosides U, V, V1-V3, W, and C1-C3; Structure elucidation; Anti-inflammatory activity;
Isolation and structure elucidation of cyclopeptide alkaloids from Ziziphus nummularia and Ziziphus spina-christi by HPLC-DAD-MS and HPLC-PDA-(HRMS)-SPE-NMR by Emmy Tuenter; Kenn Foubert; Dan Staerk; Sandra Apers; Luc Pieters (163-169).
Seven cyclopeptide alkaloids were isolated from the stem bark of Ziziphus nummularia and Ziziphus spina-christi. Three previously undescribed compounds were identified: nummularine-U, spinanine-B and spinanine-C, together with the known compounds mauritine-F, nummularine-D, nummularine-E and amphibine-D. For their purification either semi-preparative HPLC with DAD and ESIMS detection or HPLC-PDA-(HRMS)-SPE-NMR was applied, together with conventional separation methods. Their structures were elucidated by spectroscopic means.Seven cyclopeptide alkaloids were isolated from the stem bark of Ziziphus nummularia and Ziziphus spina-christi. Three previously undescribed compounds were identified: nummularine-U, spinanine-B and spinanine-C, together with four known cyclopeptide alkaloids.Display Omitted
Keywords: Ziziphus nummularia; Ziziphus spina-christi; Rhamnaceae; Cyclopeptide alkaloids;
Benzofuran glycosides and coumarins from the bark of Streblus indicus (Bur.) Corner by Ruijie He; Yanjun Zhang; Liangdeng Wu; Hui Nie; Yan Huang; Buming Liu; Shengping Deng; Ruiyun Yang; Shuai Huang; Zhijie Nong; Jun Li; Haiyan Chen (170-177).
Two pairs of rare benzofuran glucoside epimers, indicuses A and B and indicuses C and D, three biogenetically related compounds indicuses E–G, and one coumarin indicus H, as well as 11 known compounds, were isolated from the bark of Streblus indicus (Bur.) Corner. The structures of indicuses A–H were elucidated by NMR and MS data, as well as by CD. (S)-Marmesinin exhibited moderate antimicrobial activity in vitro against Bacillus subtilis and Saccharomyces cerevisiae. 7,8-Dihydroxy-3-(3-methyl-2-butenyl) coumarin, umbelliferone, and scopoletin displayed strong cytotoxic activity in vitro against human bladder carcinoma cell line EJ. The structure-activity relationships indicate that hydroxylation at C-7 in the cytotoxic compounds is crucial to their activities.Seven benzofuran glycosides and a coumarin, together with 11 known compounds, were isolated from the bark of Streblus indicus (Bur.) Corner. Their structures were elucidated by NMR and MS, as well as by use of quantum chemical CD calculations.Display Omitted
Keywords: Streblus indicus (Bur.) Corner; Streblus lour; Moraccae; Benzofuran glycoside; Coumarin; Cytotoxicity;