Impacts of simulated drought stress and artificial damage on concentrations of flavonoids in Jatropha curcas (L.), a biofuel shrub.

We studied the possible roles of flavonoids in the antioxidant and antiherbivore chemistry in Jatropha curcas (L.), a Latin American shrub that holds great potential as a source of biofuel. Changes in flavonoid concentrations in the leaves of J. curcas seedlings exposed to artificial damage and to different rainfall patterns were assessed by applying a 32-factorial experiment in a greenhouse. The concentrations of different flavonoids in the leaves of seedlings were significantly affected by interaction effects of artificial damage, drought stress and age of the seedling. The highest flavonoid concentrations were obtained in seedlings imposed to the highest percentage of artificial damage (50 %) and grown under extreme drought stress (200 mm year-1). In this treatment combination, flavonoid concentrations were three-fold as compared to seedlings exposed to the same level of artificial damage but grown in 1900 mm year-1 rainfall application. Without artificial damage, the concentration of flavonoids in the seedlings grown in 200 mm year-1 rainfall application was still two-fold compared to seedlings grown in higher (>800 mm year-1) rainfall applications. Thus, the observed flavonoid concentration patterns in the leaves of J. curcas seedlings were primarily triggered by drought stress and light rather than by artificial damage, suggesting that drought causes oxidative stress in J. curcas.

Profiling of Coumarins in Peucedanum palustre (L.) Moench Populations Growing in Finland.

The coumarin composition of Peucedanum palustre (L.) Moench populations growing in Finland was investigated. A total of 132 flowering P. palustre specimens from 43 locations in southern and central Finland were collected, divided into root, stem, leaf, and umbel samples, and analyzed by HPLC. HPLC coupled to high-resolution mass spectrometry was used to aid the identification of coumarins. A total of 13 coumarin-structured compounds were quantitatively analyzed from the samples. The coumarin profile of root samples was found to differ from the aerial plant parts. The main coumarins in roots were oxypeucedanin and columbianadin. In aerial parts, peulustrin isomers were the most abundant coumarin components. Umbels and leaves also contained a considerable amount of umbelliprenin, which was only found in traces in roots. Based on hierarchical cluster analysis of the coumarin profiles, some populations shared common characteristics. The most distinct property connecting certain populations was their high peulustrin content. Another notable common property between some populations was the high umbelliprenin content in aerial plant parts. Some populations were clustered together due to their low overall coumarin content.

Hepatoprotective and antioxidant effect of Bauhinia hookeri extract against carbon tetrachloride-induced hepatotoxicity in mice and characterization of its bioactive compounds by HPLC-PDA-ESI-MS/MS.

The hepatoprotective and antioxidant activity of Bauhinia hookeri ethanol extract (BHE) against CCl4-induced liver injury was investigated in mice. BHE was administered (500 and 1000 mg/kg/day) along with CCl4 for 6 weeks. The hepatic marker enzymes: alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were determined in the serum. The antioxidant parameters: glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione transferase (GST), and malondialdehyde (MDA) were estimated in the liver homogenate. BHE treatment significantly inhibited the CCl4-induced increase in ALT (44 and 64%), AST (36 and 46%), ALP (28 and 42%), and MDA (39 and 51%) levels at the tested doses, respectively. Moreover, BHE treatment markedly increased the activity of antioxidant parameters GSH, GPx, GR, GST, and SOD. Histological observations confirmed the strong hepatoprotective activity. These results suggest that a dietary supplement of BHE could exert a beneficial effect against oxidative stress and various liver diseases by enhancing the antioxidant defense status, reducing lipid peroxidation, and protecting against the pathological changes of the liver. The hepatoprotective activity of BHE is mediated, at least in part, by the antioxidant effect of its constituents. The active constituents of BHE were identified by HPLC-PDA-ESI/MS/MS.

The offline combination of thin-layer chromatography and high-performance liquid chromatography with diode array detection and micrOTOF-Q mass spectrometry for the separation and identification of spinochromes from sea urchin (Strongylocentrotus droebachiensis) shells.

Thin-layer chromatography (TLC) with off-line high-performance liquid chromatography coupled to diode array detection and micrOTOF-Q mass spectrometry (HPLC-DAD-MS) resulted in the successful fractionation, separation and identification of spinochrome pigments from sea urchin (Strongylocentrotus droebachiensis) shells. Two fractions of pigments were separated by TLC and eluted with methanol using a TLC-MS interface. HPLC-DAD-MS analysis of the fractions indicated the presence of six sea urchin pigments: spinochrome monomers B and D, three spinochrome dimers (anhydroethylidene-6,6'-bis(2,3,7-trihydroxynaphthazarin) and its isomer and ethylidene-6,6'-bis(2,3,7-trihydroxynaphthazarin)), and one pigment that was preliminary identified as a spinochrome dimer with the structural formula C(22)H(16)O(16).

Phenolic compounds from Eucalyptus gomphocephala with potential cytotoxic and antioxidant activities.

Two new phenolic compounds, 2,4,6-trihydroxy-5-methyl-acetophenone 2-O-beta-D-glucopyranoside (3), and benzyl alcohol 7-O-(3',4',6'-tri-O-galloyl)-beta-D-glucopyranoside (8), together with eight known phenolic compounds, were isolated from the 70% aqueous acetone extract of Eucalyptus gomphocephala DC. (Myrtaceae). The isolated compounds were elucidated based on their 1H, 13C, DQF-COSY, selective 1D-TOCSY, HSQC, and HMBC NMR spectroscopic and ESI-MS data. The antioxidant effect of the phenolic compounds was tested using 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical and super oxide anion radical scavenging assays. The cytotoxicity of the isolated compounds was evaluated using HeLa cell line.

Feeding on poplar leaves by caterpillars potentiates foliar peroxidase action in their guts and increases plant resistance.

Peroxidases (PODs) are believed to act as induced and constitutive defenses in plants against leaf-feeding insects. However, little work has examined the mode of action of PODs against insects. Putative mechanisms include the production of potentially antinutritive and/or toxic semiquinone free radicals and quinones (from the oxidation of phenolics), as well as increased leaf toughness. In this study, transgenic hybrid poplar saplings (Populus tremula × Populus alba) overexpressing horseradish peroxidase (HRP) were produced to examine the impact of elevated HRP levels on the performance and gut biochemistry of Lymantria dispar caterpillars. HRP-overexpressing poplars were more resistant to L. dispar than wild-type (WT) poplars when the level of a phenolic substrate of HRP (chlorogenic acid) was increased, but only when leaves had prior feeding damage. Damaged (induced) leaves produced increased amounts of hydrogen peroxide, which was used by HRP to increase the production of semiquinone radicals in the midguts of larvae. The decreased growth rates of larvae that fed on induced HRP-overexpressing poplars resulted from post-ingestive mechanisms, consistent with the action of HRP in their midguts. The toughness of HRP-overexpressing leaves was not significantly greater than that of WT leaves, whether or not they were induced. When leaves were coated with ellagitannins, induced HRP leaves also produced elevated levels of semiquinone radicals in the midgut. Decreased larval performance on induced HRP leaves in this case was due to post-ingestive mechanisms as well as decreased consumption. The results of this study provide the first demonstration that a POD is able to oxidize phenolics within an insect herbivore's gut, and further clarifies the chemical conditions that must be present for PODs to function as antiherbivore defenses.

Chemical composition and bioactivity of Pleiogynium timorense (Anacardiaceae).

A liquid chromatography-diode array detection-electrospray ionization mass spectrometric (HPLC-PDA-ESI/MS/MS) method was used for the analysis of the phenolic composition of the ethanolic extract obtained from the leaves of Pleiogynium timorense (DC.) Leenh. Twenty compounds were detected and tentatively characterized. In addition, further phytochemical investigations of the extract resulted in the isolation of twelve major phenolic compounds. Evidence of the structures of these compounds was obtained based on the interpretation of the UV, 1H NMR, 13C NMR and DQF-COSY spectral data. The antioxidant effect of the ethanolic extract was examined in vitro using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and super oxide anion radical scavenging assays. DPPH radical scavenging activity was observed for the extract, with an IC50 of 21.9 microg/mL, while its super oxide anion scavenging activity was less pronounced, with an IC50 of 123.5 microg/mL The ethanolic extract showed significant hypoglycemic, antioxidant and anti-inflammatory properties. This study suggests that the ethanolic extract of Pleiogynium timorense is a potential source of antioxidant compounds, relatively non-toxic, and have possible beneficial health effects.

Electron ionization mass spectra and tautomerism of substituted 2-phenacylquinolines.

Tautomerism has been studied conventionally in solutions or in the solid state. However, the importance of mass spectrometry in the gas phase was realized relatively late. 2-Phenacylquinolines are known to undergo ketimine-enaminone tautomerism. The ratio of tautomers is dependent on the nature of the phenyl ring substituent and the Hammett substituent constants sigma. Theoretical calculations indicate the presence of ketimine and enaminone tautomers in the gas phase. The electron ionization mass spectra of eight 2-phenacylquinolines (ketimine form) were recorded at 70 eV in order to determine the fragmentation routes and to screen for the presence of their enaminone tautomers, (Z)-2-benzoylmethylene-1,2-dihydroquinolines, in the gas phase. The relative abundances or total ion currents of some ions correlated with the Hammett substituent constants and Hammett-Brown constants. The product ions [M-CO](+.) and [M-HCO](+) were observed. A reaction mechanism is suggested for the formation of these ions, requiring skeletal rearrangements. The results furnish information relating to tautomerism in the gas phase.

Electron ionization mass spectra of aryl- and benzyl-substituted 2,3-dihydroimidazo[1,2-a]pyrimidine-5,7(1H,6H)-diones.

The electron ionization mass spectra of the 1-phenyl-, 1-benzyl- and 6-benzyl-1-phenyl-2,3-dihydroimidazo[1,2-a]pyrimidine-5,7(1H,6H)-dione derivatives were recorded at 70 eV to find out the effects of substituents on their fragmentations. Fragmentation pathways were studied using B/E and B(2)/E scans. Some fragmentations involved the loss of C(3)HO(2) or carbon suboxide. The possibility of keto-enol tautomerism was also studied. For comparison selected compounds were studied using (1)H and (13)C NMR spectroscopy to reveal the presence of possible tautomerism. Some ions including [M-OH](+) and [M-HCO](+) and NMR results indicate that the enol form is predominant both in the gas and in the liquid phase.

Does the electron ionization induced fragmentation of partly saturated stereoisomeric pyrrolo- and isoindoloquinazolinones show stereospecificity?

The electron ionization mass spectrometric behavior of pyrroloquinazolinones (1-6) and isoindoloquinazolinones (7-14) was studied. These compounds were further classified as partly saturated pyrroloquinazolinones (1-3), benzologues (7-11), methylene-bridged derivatives (4-6, 12, 13) and a bisacyl compound (14). The mass spectra of the pyrrolo- and isoindoloquinazolinones did not exhibit stereospecific retro-Diels-Alder (RDA) fragmentations. The cyclohexane-fused compounds 7 (cis annelated) and 8 (trans annelated) did display some other ions differing in their abundances that could be used to differentiate this pair of stereoisomers. Also the cyclohexene-fused compounds 2, 3, 9 and 10 exhibited somewhat different ion abundances pairwise that could be utilized for isomeric differentiation. Earlier hypothesis of pyrrolo ring cleavage via the loss of C(3)H(5)O(.) was strengthened by the fragmentation of compounds 1-4. RDA(+/-H) fragmentation is more favorable than the formation of [M-R](+) ions (R=H, C(6)H(4)CH(3), or C(6)H(4)Cl) when an unsaturated bicyclic group is present but both RDA fragmentation and [M-R](+) formation occur for cyclohexene-fused compounds, possibly because of the lower ring strain than with norbornene-fused compounds. The [M-H](+) ion was abundant for compounds 7 and 8 as was [M-Ar](+) for 1-4 and 11. Although the compounds studied might participate in amide-imidol tautomerism, no indication of such tautomerism was detected.

Electron ionization mass spectra of 8-aryl-3,4-dioxo-2H,8H-6,7-dihydroimidazo[2,1-c][1,2,4]triazines. Do they exhibit tautomerism in the gas phase?

The electron ionization mass spectra of the title compounds (1: a R = H, b 2-CH(3), c 4-CH(3), d 2,3-diMe, e 2-OCH(3), f 4-OCH(3), g 2-Cl, h 3-Cl, i 4-Cl, j 3,4-diCl) were recorded at 70 eV to determine the effects of substituents and the possible keto-enol tautomerism. The compounds showed several common fragment ions but also fragment ions which divided them into three classes, namely 1a-1d (parent compound and Me-substituted derivatives), 1e and 1f (MeO-substituted derivatives), and 1g-1j (Cl-substituted derivatives). The presence of the HOCN(+.) ion as well as the exponential dependence of its total ion current in the case of p- and also 3-Cl-substituted compounds (1a, c, f, h-j) on the Hammett sigma constants and the loss of CHO or one or two HOCN moieties can be somewhat easier explained by the presence of the enol form but as a whole the results support the predominance of the keto form, in parallel to the situation in solution.

Electron ionization mass spectra of phosphorus-containing heterocycles. II. 1,2,3,4,4a,5,6,7,8,8a-decahydro-1,3,2-benzodiazaphosphinine 2-oxides.

The electron ionization mass spectra of cis- and trans-fused 1,2,3,4,4a,5,6,7,8,8a-decahydro-1,3,2-benzodiazaphosphinine 2-oxides (1-17) were recorded, and the fragmentation pathways were established and compared with those of 1,4,4a,5,6,7,8,8a-octahydro-2H-3,1,2-benzoxazaphosphinine 2-oxides. In general, the mass spectral behaviors of the isomeric compounds were very similar and it was mostly impossible to differentiate them from each other on the basis of the relative abundances of their characteristic fragment ions. The compounds in which R(2) = Ph or OPh exhibited a series of common fragments, e.g. [R(2)H](+), R(2)PONHR(1(3)+), [M-C(3)H(7)](+) and [M-C(4)H(9)](+), the latter two ions being present in the spectra of only two of the derivatives with an N(CH(2)CH(2)Cl)(2) substituent on the P atom. When R(2) = Ph, numerous other alkyl radicals, alkenes and a cycloalkane were also ejected and these compounds also lost NH(2), NH(3), CH(3)N, CH(4)N or CH(3)NH(2). The compounds with an N(CH(2)CH(2)Cl)(2) substituent on the P atom most closely resembled their 3,1,2-O,N,P analogs in respect of the dominant role of this substituent.

Electron ionization mass spectra and tautomerism of 2-phenacylpyridines.

The electron ionization mass spectra of 2-phenacylpyridine (ketimine form) and its 13 derivatives substituted in the benzene ring (1an: a R = H, b 3-Me, c 4-Me, d 4-NH(2), e 3-F, f 4-F, g 4-OMe, h 4-Cl,i 4-N(CH(3))(2),j 4-NO(2), k 4-CF(3), l 4-N(CH(2))(4), m 4- Br, n 3-Br) were recorded at 70 eV to determine the fragmentation routes and to screen the presence of their enolimine tautomers, (Z-)-2-(2-hydroxy-2-phenylvinyl)pyridines in the gas phase. The total ion currents (TIC) of the ions [MH](+), [MHCO](+), 2-PyCH(2)O(+), and RC(6)H(4)CO(+) (= ArCO(+) ) showed a fair or good correlation with the Hammett s constants (R = 0.859, 0.876, 0.912, and 0.926, respectively). The relative abundances (RA) of both the [MCO](+.) and the [MHCO](+) ion increased with the decreasing electron donating ability of the substituents and also correlated relatively well with the Hammett constants (R = 0.834 and 0.907, respectively). These observations, in comparison to the NMR results, show that the relative contribution of the ketimine tautomer also increases in the gas phase with the increasing electron donating ability of the phenyl substituent, i.e. the TIC of the ArCO(+) ion decreases whereas that of [MH](+) ion increases.

Electron ionization mass spectra of phosphorus-containing heterocycles. I. 1,4,4a,5,6,7,8,8a-octahydro-2H-3,1,2-benzoxazaphosphinine 2-oxides.

The electron ionization mass spectra of 27 cis- and trans-annelated 1,4,4a,5,6,7,8,8a-octahydro-2H-3,1,2-benzoxazaphosphinine 2-oxides were recorded to clarify the effects of the ring heteroatom (O or N), ring annelation, the P configuration and the substituents attached to the ring or to the N and P atoms. For compounds 1-12 different alkyl radical and alkene losses and the cleavage of the P-heteroatom bonds, instead of the P-C bonds, were representative and dependent mainly on the substitution on the N and P atoms. The replacement of Ph and OPh by N(CH2CH2Cl)2 on the P atom had a dramatic influence on the fragmentation process: new fragment ions were obtained and very little M+ (1-3%) was formed. Only slight differences were found between some of the corresponding isomers, but interestingly the compounds formed clear groups on the basis of the differences in their fragmentation, depending on the ring-N and ring-P substituents.