Optimization of SPME-Arrow-GC/MS Method for Determination of Free and Bound Volatile Organic Compounds from Grape Skins.

(1) Background: Solid phase microextraction (SPME)-Arrow is a new extraction technology recently employed in the analysis of volatiles in food materials. Grape volatile organic compounds (VOC) have a crucial role in the winemaking industry due to their sensory characteristics of wine.; (2) Methods: Box-Behnken experimental design and response surface methodology were used to optimise SPME-Arrow conditions (extraction temperature, incubation time, exposure time, desorption time). Analyzed VOCs were free VOCs directly from grape skins and bound VOCs released from grape skins by acid hydrolysis.; (3) Results: The most significant factors were extraction temperature and exposure time for both free and bound VOCs. For both factors, an increase in their values positively affected the extraction efficiency for almost all classes of VOCs. For free VOCs, the optimum extraction conditions are: extraction temperature 60 °C, incubation time 20 min, exposure time 49 min, and desorption time 7 min, while for the bound VOCs are: extraction temperature 60 °C, incubation time 20 min, exposure time 60 min, desorption time 7 min.; (4) Conclusions: Application of the optimized method provides a powerful tool in the analysis of major classes of volatile organic compounds from grape skins, which can be applied to a large number of samples.

Chemical characterization, antiproliferative and antifungal activities of Clinacanthus nutans.

Clinacanthus nutans Lindau (Family: Acanthaceae) is a medicinal herb widely distributed in the tropic and subtropic areas of Asia. C. nutans is traditionally consumed as vegetable or herbal tea, as well as a folk medicine for anticancer and antifungal activities. However, to date, chemical constituent responsible for observed health beneficial effects of this medicinal plant is not clear. In the current study, 32 compounds (1-32), including three new megastigmanes (1-3) were isolated from the aerial parts of C. nutans. Their structures were elucidated on the basis of comprehensive NMR, MS, and CD spectroscopic data analysis, as well as chemical hydrolysis. Among the isolates, cycloartane triterpenoids (9, 10, and 12) displayed moderate anti-proliferative effects against HepG2 cell growth with IC50 values ranging from 9.12 to 19.89 µM. Data obtained from flow cytometry analysis and western blotting assays revealed that compounds 9 and 12 induced apoptosis of HepG2 cells by modulating the expression of proteins associated to mitochondrial-mediated apoptotic pathway. Furthermore, megastigmanes 1, 2, 7, and 8 enhanced the anti-Candida albicans activity of amphotericin B (AmB), supporting the synergistic effects between megastigmanes and AmB. This is the first report of anticancer and antifungal potential of cycloartane triterpenoids and megastigmanes in C. nutans, which shed useful insights on the relationship between C. nutans's chemical constituent and its beneficial effects to health. Findings from this study support further development of this medicinal plant for potential pharmaceutical applications.

Megastigmane Derivatives from the Cladodes of Opuntia humifusa and Their Nitric Oxide Inhibitory Activities in Macrophages.

Opuntia humifusa, known as the eastern prickly pear cactus and locally called "Cheonnyuncho" in Korea, is cultivated widely on Jeju Island, Korea. Phytochemical analysis of the methanolic extract of the cladodes of O. humifusa, for which previous research is relatively limited, was performed under the guidance of LC/MS-based analysis. As a result, one new megastigmane (1) and four new megastigmane glucosides (2-5) were isolated along with 18 known compounds (6-23). The structures of the new compounds were established by 1D and 2D NMR and HRESIMS, and their absolute configurations were established by chemical reactions, quantum chemical electronic circular dichroism calculations, and DP4+ analysis using the gauge-including atomic orbital NMR chemical shift calculations as well as the application of Snatzke's method. The isolated compounds (1-23) were tested for NO production inhibition in lipopolysaccharide (LPS)-induced RAW 264.7 cells to investigate their anti-inflammatory effects. Compounds 10 and 11 exhibited significant inhibitory effects on LPS-induced NO production in a dose-dependent manner. The potential mechanistic pathway of 10 and 11 was also investigated using Western blotting, indicating that compounds 10 and 11 inhibit NO through iNOS expression.

Labdanes and megastigmanes from Vitex negundo var. heterophylla.

The aromatic plants of Vitex negundo var. heterophylla are not only herb medicine but also a functional food and an industrial crop. Its leaves can be used as a functional food for improving human's health, but the previous studies mainly focused on the volatile constituents, lignans, and iridoids. Our research led to the isolation of four new terpenoids (1-4), together with fifteen known compounds including seven flavonoids (9-15), two jasmonates (7-8) and six terpenoids (5-6, 16-19) from the leaves. Among all these compounds, 1, 2, 11, and 19 exhibited strong inhibitory activity against NO production in lipopolysaccharide (LPS)-induced RAW264.7 macrophage. The anti-inflammatory mechanism of the most active compound (2) is related to the inhibition of iNOS and COX-2, and the suppression of NF-κB pathway. Therefore, terpenoids and flavonoids from the leaves of Vitex negundo var. heterophylla might be used as potential anti-inflammatory candidates for developing medicine or value-added functional food.

Triterpenoids, megastigmanes and hydroxycinnamic acid derivatives from Anisomeles indica.

Six triterpenoids (1-6), four megastigmanes (7-10) and five hydroxycinnamic acid derivatives (11-15) were isolated from the aerial part of Anisomeles indica (Lamiaceae). Of these components, compound 1 was identified to be a new triterpenoid with the structure of 2α,3α,19α-trihydroxyurs-12,20(30)-dien-28-oic acid based on extensive analysis of MS, 1D and 2D NMR spectroscopic data, while compounds 2-13 were obtained for the first time from Anisomeles species.

A new norisoprenoid from the leaves of Ficus pumila.

One new norisoprenoid 3,9-dihydroxy dihydro actinidiolide (1), together with eleven known compounds (2-12), were isolated from ethanol extract of the leaves of Ficus pumila collected in Hainan Province, China. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Compounds 1, 2, 4, 5, 8 and 10-12 were isolated from the F. pumila for the first time. All compounds were evaluated for their cytotoxic activity. Compounds 3 and 9 showed weak cytotoxic activity against Hela, MCF-7 and A549 cell lines.

HPTLC Autography Based Screening and Isolation of Mushroom Tyrosinase Inhibitors of European Plant Species.

In the course of this project, 133 plants were evaluated on their ability to inhibit tyrosinase, a key enzyme in melanogenesis. The screening was performed by means of a HPTLC autographic assay, resulting in the selection of three plants, Asplenium trichomanes, Pinus uncinata, and Scutellaria altissima, with promising tyrosinase inhibiting activities. With the aid of the HPTLC assay, it was not only possible to select the most interesting plant extracts, but also to monitor the activity-guided fractionation which, in a relatively short time period, led to the isolation of active principles. Benzoic acid, roseoside, and dihydrovomifoliol-O-ß-d-glucopyranoside could be identified as tyrosinase inhibitors present in P. uncinata. Globularin turned out to be the active principle of S. altissima, and 4-ethenylphenyl 6-O-(6-deoxy-α-l-mannopyranosyl)-ß-d-glucopyranoside was detected as tyrosinase inhibitor of A. trichomanes. The pure compounds were tested also in a 96 well-plate assay in order to determine their IC50 values. The lowest IC50 value (42 µm) could be obtained for globularin, whereas the other compounds, e. g., benzoic acid exhibited a rather high IC50 value (IC50 =552 µm). This stood in clear contrast to the autographic assay, but is has to be taken into account that the outcome of the autography assay is not only depending on the IC50 value of a compound, but also on the content of the respective constituent in the extract.

Megastigmane glycosides from Urena lobata.

Five new megastigmane glycosides, urenalobasides A-E (1-5), together with 11 known ones (6-16) were isolated from Urena lobata. Their structures were determined by extensive spectroscopic and spectrometric data (1D and 2D NMR, IR, and HRESIMS) and calculated electronic circular dichroism method. Compounds 1 and 2 are two unusual megastigmanes structurally containing a 6/5 fused ring system. Compound 3 exhibits inhibition of nitric oxide production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with IC50 value of 53.7 ±â€¯1.0 µM (positive control, dexamethasone, IC50 = 16.6 ±â€¯0.8 µM).

Megastigmane glucosides isolated from Dichrocephala benthamii.

The present study was designed to investigate the chemical constituents of the whole herb of Dichrocephala benthamii. A new megastigmane glucoside (compound 1), together with its four known analogues (compounds 2-5), was obtained. Their structures were elucidated on the basis of spectroscopic analyses (UV, IR, MS, and 1D and 2D NMR). The absolute configuration of compound 1 was assigned on the basis of CD method and chemical evidence. In addition, their cytotoxicity against human hepatoma cells (HepG-2) was evaluated by the MTT method. Compound 5 showed weak activity against HepG-2, while the other compounds did not show remarkable inhibitory effects.

The constituents of essential oil in leaves of Karaj accession of Trigonella foenum graecum.

The chemical composition of the essential oils of Karaj accession of Trigonella foenum graecum leaves was detected by hydro-distillation and analysed by gas chromatography (GC-FID) and gas chromatography-mass spectroscopy (GC-MS) apparatuses for first time. Thirty-six compounds representing 95.3% of the total components were identified. The patterns of the main compounds were (2E)-Hexenal (26.61%), n-Hexadecanoic acid (10.14%) and (E)-b-Ionone (7.99%). Other notable constituents were Thymol (4.79%), 6,10,14-trimethyl-2-Pentadecanone (4.59%), Carvacrol (3.40%), (E)-Nerolidol (3.32%) and (2E,6Z)-Nonadienal (3.30%). (2E)-Hexenal was found as the most dominant component in this study.

Two new megastigmanes from Chinese traditional medicinal plant Sedum sarmentosum.

To discover new bioactive compounds from nature plants, a primary screening of traditional Chinese medicines had been taken. The screening results showed that a EtOAc extract of Sedum sarmentosum displayed a certain degree of cytotoxic activity and bioassay-directed isolation of EtOAc extract gave two new megastigmanes, (6S,9R)-2-hydroxy-4-(2,6,6-trimethyl-4-oxo-cyclohex-2-enyl)-butyric acid (1) and (6S,9R)-2-hydroxy-4-(2,6,6-trimethyl-4-oxo-cyclohex-2-enyl)-butyric acid methyl ester (2) together with seven known flavonoids. The chemical structures of 1 and 2 were elucidated on the basis of detailed 1D, 2D NMR and MS data. When tested against HepG2 and Hep3B hepatocellular carcinoma cell lines, compounds 1-9 showed weak anti-HCC activity. In addition, in vitro antioxidant activities of 1-9 were evaluated by ABTS radical cation-scavenging assay. 1 and 2 exhibited weak activity with per micromoles equivalent to 0.039 and 0.042 µM of Trolox, respectively. The flavonoid component, quercetin (9) showed the highest antioxidant activities with per micromoles equivalent 0.67 µM of Trolox.

Neolignan and megastigmane glucosides from the aerial parts of Isodon japonicus with cell protective effects on BaP-induced cytotoxicity.

Six neolignan glucosides, named isodonosides I-VI, and a megastigmane glucoside named isodonmegastigmane I, were isolated together with 15 known compounds from the methanolic extract of aerial parts of Isodon japonicus cultivated in Tokushima, Japan. The chemical structures of the compounds were elucidated based on their MS and NMR spectroscopic analysis. The absolute configurations of the neolignan and megastigmane glucosides were determined by derivatizations, by ECD (electronic circular dicroism) Cotton effect approximation, and by the modified Mosher's method. In addition, a significant cell protective effects of neolignan glucosides on benzo[a]pyrene-induced cytotoxicity was found.

3-Hydroxy-4,7-megastigmadien-9-one, isolated from Ulva pertusa, attenuates TLR9-mediated inflammatory response by down-regulating mitogen-activated protein kinase and NF-κB pathways.

CONTEXT: Seaweeds are rich in bioactive compounds in the form of vitamins, phycobilins, polyphenols, carotenoids, phycocyanins and polysaccharides; many of these are known to have advantageous applications in human health. 3-Hydroxy-4,7-megastigmadien-9-one (comp) was isolated from Ulva pertusa (U. pertusa) Kjellman (Ulvaceae), which is a familiar edible green seaweed. OBJECTIVE: This study evaluates the anti-inflammatory activity of comp in CpG DNA-stimulated bone marrow-derived dendritic cells (BMDCs). MATERIALS AND METHODS: For evaluating the effect of comp on cytokines production, BMDCs were treated with doses of comp (0, 0.5, 1, 2, 5, 10, 25 and 50 µM) for 1 h before stimulation with CpG DNA (1 µM). Cytokine production was measured by ELISA. Western blotting was conducted for evaluating effect of comp (50 µM) on MAPKs and NF-κB pathways. Luciferase reporter gene assay was conducted for effect of comp (0, 5, 10 and 25 µM) on transcriptional activity of AP-1 and NF-κB. RESULTS: Comp exhibited strong inhibition of interleukin (IL)-12 p40, IL-6 and TNF-α cytokine production with IC50 values of 6.02 ± 0.35, 27.14 ± 0.73, and 7.56 ± 0.21 µM, respectively. It blocked MAPKs and NF-κB pathways by inhibiting the phosphorylation of ERK1/2, JNK1/2, p38 and IκBα. In addition, it strongly inhibited the transcriptional activity of AP-1 and NF-κB with IC50 values of 8.74 ± 0.31 and 12.08 ± 0.24 µM, respectively. DISCUSSION AND CONCLUSION: Taken together, these data suggest that comp has a significant anti-inflammatory property and warrants further studies concerning the potential of comp for medicinal use.

Megastigmane glycosides from leaves of Eucommia ulmoides Oliver with ACE inhibitory activity.

Four new megastigmane glycosides, eucomegastigsides A-D (2, 3, 5 and 7), together with three known megastigmane glycosides, (6R, 7E, 9R)-9-hydroxy-4, 7-megastigmadien-3-one-9-O-[α-l-arabinopyranosyl-(l→6)-ß-d-glucopyranoside (1), foliasalacioside B1 (4) and eleganoside A (6), were isolated from the leaves of Eucommia ulmoides Oliver. Their anti-hypertensive effect was investigated in vitro based on the inhibition of Angiotensin Converting Enzyme (ACE) using HPLC. The results showed that the isolates (2, 3, 4, 5, 7) had moderate inhibitory effects on ACE in vitro compared with captopril.

Two New Compounds from the Leaves of Glochidion obliquum.

Using combined chromatographic methods, two new compounds, 6ß,9ß:9,13-diepoxymegastig-4-en-3ß-ol (1), 5a,6a-epoxy D:C-friedoolean-8-en-3ß-ol (2) were isolated from the methanol extract of the leaves of Glochidion obliquum Decne. Their structures were elucidated by 1D- and 2D-NMR spectra and in comparison with those reported in the literature.

Officinalioside, a new lignan glucoside from Borago officinalis L.

A new lignan glucoside, officinalioside (1), was isolated from n-BuOH fraction of the aerial parts of Borago officinalis L., together with four known compounds: actinidioionoside (2), roseoside (3), crotalionoside C (4) and kaempferol 3-O-ß-D-galactopyranoside (5). The structure of the new compound was established by means of spectroscopic and chemical analyses. Compounds 1 and 2 showed a moderate DPPH radical scavenging activity (IC50: 52.6 ± 1.70 and 41.3 ± 0.25 µM, respectively) comparable with that of the standard trolox (16.6 ± 2.2 µM) without any significant cytotoxicity towards human cell line A549 (IC50 > 100 µM).

Chemical composition and biological evaluation of the volatile constituents from the aerial parts of Nephrolepis exaltata (L.) and Nephrolepis cordifolia (L.) C. Presl grown in Egypt.

The essential oil from the aerial parts of Nephrolepis exaltata and Nephrolepis cordifolia obtained by hydro-distillation were analyzed by gas chromatography/ mass spectrometry. The essential oils exhibited potential antibacterial and antifungal activities against a majority of the selected microorganisms. NEA oil showed promising cytotoxicity in breast, colon and lung carcinoma cells. The results presented indicate that NEA oil could be useful alternative for the treatment of dermatophytosis. Comparative investigation of hydro-distilled volatile constituents from aerial parts (A) of Nephrolepis exaltata (NE) and Nephrolepis cordifolia (NC) (Family Nephrolepidaceae) was carried out. Gas chromatography/mass spectrometry revealed that oils differ in composition and percentages of components. Oxygenated compounds were dominant in NEA and NCA. 2,4-Hexadien-1-ol (16.1%), nonanal (14.4%), ß-Ionone (6.7%) and thymol (2.7%) were predominant in NEA. ß-Ionone (8.0%), eugenol (7.2%) and anethol (4.6%) were the main constituents in NCA. Volatile samples were screened for their antibacterial and antifungal activities using agar diffusion method and minimum inhibitory concentrations. The cytotoxic activity was evaluated using viability assay in breast (MCF-7), colon (HCT-116) and lung carcinoma (A-549) cells by the MTT assay. The results revealed that NEA oil exhibited potential antimicrobial activity against most of the tested organisms and showed promising cytotoxicity.

Structural elucidation of two new megastigmane glycosides from the leaves of Aquilaria sinensis.

The present study was designed to determine the chemical constituents and identify new components of the leaves of Aquilaria sinensis (Lour.) Gilg. The compounds were isolated and purified by repeated silica gel, Sephadex LH-20, and ODS column chromatography and their structures were elucidated by NMR and HR-ESI-MS spectrometry. Eight megastigmane glycosides and two cucurbitacins were isolated and identified as (9S) megastigma-4,7-diene-2,3,9-triol 9-O-ß-D-glucopyranoside (1), (9S) megastigma-4(13),7-diene-3,6,9-triol 9-O-ß-D-glucopyranoside (2), macarangloside D (3), corchoionoside C (4), staphylionoside H (5), (+) 3-oxo-α-ionol-ß-D-glucopyranoside (6), (-) 3-oxo-α-ionol-ß-D-glucopyranoside (7), citroside B (8), 2-O-ß-D-glucopyranosyl cucurbitacin I (9), bryoamaride (10). Compounds 1 and 2 were newly identified megstigmane glucosides and reported from this genus for the first time.

Characteristic Chemical Components and Aroma-active Compounds of the Essential Oils from Ranunculus nipponicus var. submersus Used in Japanese Traditional Food.

Ranunculus nipponicus var. submersus is an aquatic macrophyte; it is known as a wild edible plant in Japan for a long time. In this study, the essential oils from the fresh and dried aerial parts of R. nipponicus var. submersus were extracted by hydrodistillation and analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). Moreover, important aroma-active compounds were also detected in the oil using GC-olfactometry (GC-O) and aroma extract dilution analysis (AEDA). Thus, 98 compounds (accounting for 93.86%) of the oil were identified. The major compounds in fresh plant oil were phytol (41.94%), heptadecane (5.92%), and geranyl propionate (5.76%), while those of. Dried plant oil were ß-ionone (23.54%), 2-hexenal (8.75%), and dihydrobovolide (4.81%). The fresh and dried oils had the green-floral and citrus-floral odor, respectively. The GC-O and AEDA results show that phenylacetaldehyde (green, floral odor, FD-factor = 8) and ß-ionone (violet-floral odor, FD-factor = 8) were the most characteristic odor compounds of the fresh oils. ß-Cyclocitral (citrus odor, FD-factor = 64) and ß-ionone (violet-floral odor, FD-factor = 64) were the most characteristic odor compounds of the dried oil. These compounds are thought to contribute to the flavor of R. nipponicus var. submersus.

New flavonoid glycosides from Sedum aizoon L.

Five new flavonoid glucosides (3-4, 10-12) and a new phenolic derivative (5), together with eight known compounds including three flavonoid glucosides (6-8), three phenolic compounds (1-2, 9) and two megastigmane glucosides (13, 14), were isolated from the ethanol extract of the aerial part of Sedum aizoon L. Among them, compounds 9, 13 and 14 were isolated and identified from this genus for the first time. The structures of compounds were elucidated on the basis of 1D and 2D NMR (HSQC, HMBC and COSY) spectra and the HR-ESI-MS data. These compounds were tested for their antibacterial efficacies against both Gram-positive and Gram-negative bacteria. Compounds 1, 2, 3, 7 and 10 showed certain antibacterial activity; it showed more potency against Gram-positive than against Gram-negative bacteria. Compound 2 showed the most pronounced antibacterial effectiveness against Staphylococcus aureus Rosenbach with MIC value of 7.8µg·mL(-1). The in vitro anti-proliferative activities against HepG2, MCF-7 and A549 tumor cell lines were also evaluated. The result suggested compound 7 exhibited moderate cytotoxic activities with IC50 values of 46.30, 75.27 and 49.76µmol/L, respectively.