Biological Evaluation of Endophytic Fungus, Chaetomium globosum JN711454, as Potential Candidate for Improving Drug Discovery

The main objective of this research work focused on investigating the biological and chemical aspects of endophytic fungus Chaetomium globosum, for pharmaceutical purposes to improve the drug discovery process. The endophytic C. globosum was isolated from healthy leaves of Egyptian medicinal plant Adiantum capillus-veneris collected from Saint Katherine Protectorate, Sinai, Egypt. The identification of C. globosum was on the basis of classical and molecular taxonomy. Gene encoding for 18S rRNA was partially sequenced, submitted to the GenBank and got the accession number JN711454, to resolve the phylogenetic relations with fungal ancestor using phylogenetic tree. To explore the biosynthetic power of endophytic C. globosum JN711454, the fungus was cultivated over five different media, oatmeal, rice, yeast malt glucose, potato dextrose agar (PDA) and Czapek’s dox media, for 3 weeks at 30 °C, followed by extraction with different solvents, ethyl acetate (EA), and methanol. The ethyl acetate extract of C. globosum cultivated on PDA medium was the most potent extract. It showed strong antioxidant activity with EC₅₀ 11.5 μg/ml, potent anticancer activity with 55 % toxicity toward HepG-2 cells at 100 μg/ml and 66 % cytotoxicity to FGC₄ cells at 250 μg/ml, promising butyrylcholinesterase inhibitory activities (>85 %), and moderate antimicrobial and stopped the attachment of HSV-2 virus to VERO cells. The metabolomic profiling of PDA–EA extract using LC–MS revealed the presence of several metabolites to which the observed bioactivities could be attributed. Here we report for the first time inhibitory activity of endophytic C. globosum JN711454 secondary metabolites to butyrylcholinesterase, one of neuro hydrolase enzymes that play a major role in development of Alzheimer’s disease.     

Inhibitory effect of extracts from Brazilian medicinal plants on the adhesion of <Emphasis Type="Italic">Candida albicans</Emphasis> to buccal epithelial cells

Plants are known to produce a plethora of secondary metabolites which are recognized as a useful source of new drugs or drug leads. Extracts and fractions of Schinus terebinthifolius Raddi (Anacardiaceae), Piper regnellii C.D.C. (Piperaceae), Rumex acetosa L. (Polygonaceae), and Punica granatum L. (Punicaceae) were assessed for their antifungal activity against eight clinical isolates of C. albicans. They were also evaluated for their effect on the adhesion of these C. albicans isolates to buccal epithelial cells (BECs). The ethyl acetate fraction from the leaves of S. terebinthifolius showed promising activity, inhibiting the growth of three C. albicans isolates at 7.8 μg ml⁻¹ and significantly inhibiting their adhesion to BEC at 15 μg ml⁻¹ . In addition, this fraction did not show cytotoxic activity against murine macrophages. The results show the potential of the plant extracts studied as a source of new antifungal compounds. Further studies are necessary for isolation and characterization of the active compounds of these plants.     

Amphidinol C,a major polyketide from an Irish strain of the dinoflagellate Amphidinium carterae

An Irish strain of the dinoflagellate Amphidinium carterae was previously shown to produce antibacterial amphidinol derivatives of unknown masses. Inspection of the major metabolites present in a bulk culture of this strain led to the isolation and structure elucidation of a new amphidinol derivative named amphidinol C featuring an unprecedented tetrahydropyran ring between the positions C-7 and C-11. The structure was determined using extensive analyses of NMR and MS data and comparison with data of analogues. The new ring was proposed to stem from a nucleophilic substitution of the sulphate present on the side chain of Amphidinol B. The major metabolites isolated were tested for their antibacterial and antifungal activities and Amphidinol C showed moderate fungicidal activity against yeast and filamentous fungi at 8–16 µg mL⁻¹.     

Composition of epicuticular wax layer of two species of Mandevilla (Apocynoideae,Apocynaceae) from Rio de Janeiro,Brazil

The chemical composition of epicuticular waxes of Mandevilla guanabarica and Mandevilla moricandiana was comparatively analyzed by extraction in n-hexane and chloroform. The mean wax content per unit of leaf area in the n-hexane extract was about 13–30 μg cm⁻² for M. guanabarica, containing 20–28% n-alkanes and 55–63% triterpenes; for M. mori-candiana, the mean content was 19 μg cm⁻², containing 73% n-alkanes and 14% triterpenes. In the chloroform extract, the wax yield was 40–80 μg cm⁻² for M. guanabarica, with about 9–11% n-alkanes and 75–82% triterpenes; while for M. moricandiana, the wax yield was 110 μg cm⁻², with 52% n-alkanes and 14% triterpenes. The major compounds identified were lupeol, pentacyclic triterpenes of the α- and β-amyrin class, and n-alkanes such as nonacosane, hentriacontane and tritriacontane. These results indicate that the quantitative chemical profiles of epicuticular waxes of M. guanabarica and M. moricandiana are distinct and could be used as an additional feature in taxonomic identification.     

A potential anti-inflammation activity and depigmentation effect of Lespedeza bicolor extract and its fractions

Postinflammatory hyperpigmentation (PIH) is an acquire hypermelanosis after cutaneous inflammation and injury. The aim of the present study was to investigate a natural ingredient with the anti-inflammatory and depigmentation activities into possible applications of postinflammatory hyperpigmentation. Methanol extracts of Lespedeza bicolor and its various fractions inhibited LPS-induced NO production in RAW 264.7 macrophages in a concentration-dependent manner. In particular, the ethyl acetate fraction was shown to be inhibition of NO production (89%) and down-regulation of iNOS mRNA without causing cytotoxicity. In addition, ethyl acetate fraction significantly attenuated LPS-induced NF-κB activation (P < 0.05), indicating the anti-inflammatory activity due to NF-κB inhibition. Moreover, extracts, mainly ethyl acetate fraction, exhibited not only DPPH free radical scavenging activity (IC₅₀, 112.45 μg/mL) with 4 times lower activity than ascorbic acid, but also anti-tyrosinase activity (IC₅₀, 1 μg/mL) with a similar activity to arbutin showing a competitive inhibitor. Furthermore, vitexin and haginins A, B and C were identified through LC–MS analysis as potential compounds responsible for these effects. These results suggest that L. bicolor extract have anti-inflammatory, antioxidant activities and tyrosinase inhibitory effect and it might be used in the management of postinflammatory pigmentation through inhibition of pathogenic process involved in hyperpigmentation.     

Antiproliferative activities of isolated flavone glycosides and fatty acids from Stachys byzantina

From the aerial parts of Stachys byzanthina C. Koch., a new flavone glycoside, was isolated for the first time in addition to known two flavone glycosides. Structures were established by conventional methods of analysis and confirmed by ¹H, ¹³C NMR and mass spectral analysis. Antiproliferative activities of isolated compounds, crude extract and fractions, fatty acids (extracts of hexane and hexane:ethyl acetate, 9:1) of aerial parts of S. byzantina were investigated against Vero (African green monkey kidney), HeLa (human uterus carcinoma) and C6 (rat brain tumor) cells in vitro and compared with 5-fluorouracil (5-FU). Antiproliferative effect of the extract, isolated flavonoids and fatty acids were tested at 100, 250, 500 and 1000 μg/mL using BrdU cell proliferation ELISA.     

Sorgoleone,a sorghum root exudate: Algicidal activity and acute toxicity to the ricefish Oryzias latipes

The discovery of natural and natural-based compounds has resulted in its application as an alternative to synthetic algicides to control harmful algae in aquatic systems. Of the many natural-product-based algicides, sorgoleone, a natural plant product from Sorghum bicolor root exudates has been investigated for its controlling effect on different algal species and its acute fish toxicity. Growth of the blue green algal species Microcystis aeruginosa Kützing was completely inhibited by the crude methanol extract of sorghum root at 20 μg mL⁻¹. The most noticeable inhibition was observed in the bioassay of n-hexane soluble extract, where 98% growth inhibition occurred in M. aeruginosa at the concentration of 1.25 μg mL⁻¹. Sorgoleone very effectively controlled blue green algae inhibiting 97% of M. aeruginosa at 0.5 μg mL⁻¹ and 99% of Anabaena affinis Lemmermann at 4 μg mL⁻¹. In contrast, inhibition of the green algae species Chlorella vulgaris Beijerinck and Scenedensmus spp. at 16 μg mL⁻¹ sorgoleone was 87 and 68%, respectively. There were no mortalities or adverse effects observed in any of the fish exposed to water control, solvent control, and a nominal concentration of 1 μg mL⁻¹ during the test period. The no observed effect concentration (NOEC) value was 1.5 μg mL⁻¹ for the tested fish (O. latipes). Sorgoleone can be considered as an effective and an ecologically and environmentally sustainable approach to controlling harmful algae.     

Determination of metoclopramide in human plasma by LC–ESI-MS and its application to bioequivalance studies

An LC–MS method for the determination of metoclopramide in human plasma was developed and validated. Sample preparation involved extraction with ethyl acetate. Chromatographic separation was performed on a Thermo Hypersil-Hypurity C₁₈ (150 mm × 2.1 mm, 5 μm) with the mobile phase consisting of 40 mM ammonium acetate–methanol–acetonitrile. A single-quadrupole mass spectrometer with an electrospray interface was operated in the selected-ion monitoring mode to detect the [M+H]⁺ ions at m/z 300 for metoclopramide and at m/z 384 for the internal standard (prazosin). The method was validated over 0.78–50.00 ng mL^?1 for metoclopramide. The recovery was 67.8–83.1%, and the limit of quantitation (LOQ) detection was 0.78 ng mL^?1 for metoclopramide. The intra- and inter-day precision of the method at three concentrations was 5.0–13.6% with accuracy of 99.2–104.0%. Stability of compounds was established in a battery of stability studies. The method was successfully applied to bioequivalence studies of metoclopramide hydrochloride tablets to obtain the pharmacokinetic parameters.     

Antibacterial and phytochemical studies on Calotropis gigantia (L.) R. Br. latex against selected cariogenic bacteria

In vitro antibacterial potential of the chloroform, ethyl acetate, hexane, methanol and aqueous extracts of Calotropis gigantia (L.) R. Br. was evaluated by using five cariogenic bacteria, Actinomyces viscosus, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus mitis and Streptococcus mutans. Agar well diffusion method and minimum inhibitory concentration (MIC) were used for this purpose. The chloroform extracted fraction of latex showed inhibitory effect against S. mutans and L. acidophilus with MIC value of 0.032 and 0.52 mg/mL, respectively. Qualitative investigation on structure elucidation of bioactive compound using IR, NMR and GC–MS techniques revealed the presence of methyl nonanoate, a saturated fatty acid.     

Antifeedant and larvicidal activity of bioactive compounds isolated from entomopathogenic fungi Penicillium sp. for the control of agricultural and medically important insect pest (Spodoptera litura and Culex quinquefasciatus)

The use of chemical insecticides in agriculture has posed several challenges to environment and ecosystem health. Pesticides of biological origin are considered to be suitable for sustainable environment. In the present study bioactive compounds from Penicillium sp. was isolated and tested for insecticidal activity on Spodoptera litura and Culex quinquefasciatus larvae. Ethyl acetate extract of Penicillium sp. were characterized using GC–MS and FT-IR analysis. GC–MS analysis showed 20 different bioactive compounds namely, Propanoic acid, ethyl ester, Acetic Acid, Propyl Ester, Isopentyl Acetate, Acetic Acid, 2-Methylpropyl Ester, Behenic alcohol, 1-Hexadecene, 1-Octadecene, 1-Hexacosanol, n-Hexadecanoic acid, 1-Tetradecanol, 1-Dodecene, Tetrydamine, and Octadecanoic acid. The presence of functional groups such as, chloroalkanes, sulfonates, phosphines, amines, carboxylic acid, alkanes, and isocyanates was identified by using FTIR. Ethyl acetate extract of Penicillium sp., were tested for larvicidal activity on Spodoptera litura and Culex quinquefasciatus larvae showed significant larval mortality after 48 h of exposure with LC₅₀: 72.205 mg/ml: LC₉₀: 282.783 mg/ml and LC₅₀: 94.701 mg/ml: LC₉₀:475.049 mg/ml respectively. High antifeedant activity was observed in 300 μg/ml at 48 h of crude extract exposure. The present study concludes that Penicillium sp., secondary metabolites are effective for control of Spodoptera litura and Culex quinquefasciatus larvae.     

Ring A-seco limonoids and flavonoids from the Kenyan Vepris uguenensis Engl. and their antioxidant activity

Two A-seco-limonoids, accorded the trivial names, uguenensene and uguenensone and a C-7 prenylated flavonoid, uguenenprenol were isolated from Vepris uguenensis (Rutaceae). In addition, 11 known compounds, niloticin, chisocheton A, kihadalactone A, limonyl acetate, methyl uguenenoate, 7-O-methylaromadenrin, flindersiamine, 8α,11-elemodiol, tricoccin S₁₃ acetate, skimmianine, and lupeol were isolated. The structures of the compounds were elucidated and characterized by spectroscopic analyses (NMR, GC–MS and IR). Antioxidant activity of the isolated compounds showed that uguenenprenol and 7-O-methylaromadenrin are good antioxidant agents. Significantly high antioxidant activity was also exhibited by 8α,11-elemodiol, which was 72% at 250 μg mL⁻¹ and 57% at 15.62 μg mL⁻¹ when tested with the deoxyribose method. The two liminoids fit nicely into the biosynthetic pathway from niloticin to methyl uguenenoate.     

Investigation of Chondrus crispus as a potential source of new antifouling agents

The search for environment-friendly and non-toxic antifouling (AF) paint components has led to the investigation of natural products from seaweeds. The defence metabolites used by algae to deter unwanted epibiosis have potential for harnessing and use in AF applications. Crude algal extracts may provide a suitable mixture of compounds with AF potency. Crude ethanol extracts of the macroalgae Chondrus crispus (Rhodophyceae), from both dried and fresh sources were tested and compared using bioassays based on five marine bacterial strains, five phytoplankton strains and two macroalgae to assess the AF efficacy. Dried extract from the algae had a lower minimum inhibitory concentration at 25 μg mL⁻¹ against the growth of bacteria and phytoplankton species than that from the fresh source. Macroalgae tests indicated that the extracts had an anti-germination activity 25–50 μg mL⁻¹ against both Undaria pinnatifida and Ulva intestinalis spores. A field trial of AF paint incorporating crude extract indicated an initial AF potency lasting six weeks.     

Cytoskeletal and developmental alterations in Ceratophyllum demersum induced by microcystin-LR, a cyanobacterial toxin

The aim of the present work was the investigation of microtubule organization related to developmental processes of Ceratophyllum demersum, a submergent aquatic macrophyte, as affected by microcystin-LR (MCY-LR), a cyanobacterial toxin. We studied the time- and dose-dependent effects of the cyanotoxin in a concentration range of 0.01-20 μg mL⁻¹ (0.01-20.1 μM) at exposure times of 2-16 d. At short term (4 d) of MCY-LR exposure we observed the inhibition of C. demersum shoot tip elongation. This phenomenon was already observed at 0.01 μg mL⁻¹ MCY-LR (reduction of shoot tip length to 56 ± 3.6% of controls) and correlated with the induction of cortical microtubule (CMT) reorientation from transverse to longitudinal known to induce radial expansion of meristematic cells instead of normal elongation. Concomitantly we detected the increase of the percentage of cells in early mitosis in shoot tip meristems, from 1.17 ± 0.2% for controls to 1.93 ± 0.3 at 0.01 μg mL⁻¹ MCY-LR and 6.19 ± 0.5 at 10 μg mL⁻¹ MCY-LR. Cyanotoxin exposure induced the inhibition of general shoot elongation that was more pronounced than inhibition of the increase of leaf whorl number or fresh weight in the treatment period and this was observable at as short as 2-4 d of 2.5 μg mL⁻¹ MCY-LR exposure. This observation further proved that the MCY-LR-induced inhibition of cell elongation is responsible mainly for growth inhibition in C. demersum. Concomitantly with developmental and growth changes MCY-LR decreased protein and chlorophyll content at 16 d of exposure: at 20 μg mL⁻¹ of cyanotoxin, protein content was reduced to 53.3 ± 2.8%, while total chlorophyll content to 46.53 ± 2.7% of controls. This is the first study showing that MCY-LR inhibits the growth of C. demersum through cytoskeletal reorganization. This plant proved to be a powerful model system for toxicological as well as plant cell biology studies.     

Effects of pear fruit-derived volatiles and their concentrations on the responses of oriental fruit moths

Grapholita molesta (Busck) is an important pest of pear trees. Numerous esters accumulate consistently in mature pear fruits. However, little is known about the effects of single esters from pear fruits at different concentrations on the responses of male and female G. molesta. In this study, the responses of virgin males, virgin females, and gravid females to five esters (3-methylbutyl acetate, ethyl hexanoate, ethyl butanoate, butyl acetate, and hexyl acetate) of pear fruits at three dosage levels (1, 5 and 10 μg/μL) were investigated using electroantennography (EAG), wind tunnel experiments, and field tests. Our results showed that ethyl butanoate (5 μg/μL) elicited higher EAG responses in virgin females and males than a mixture of all five volatiles, and elicited an equal EAG response to that for the mixture in gravid females, with all responses to ethyl butanoate and the mixture being higher than the response to hexane alone. For upwind flight, ethyl butanoate (5 μg/μL) excited equal moth flight–location behavior in virgin and gravid females to that for the mixture, which were both higher than the response to hexane. For close flight, ethyl hexanoate (5 μg/μL) and 3-methylbutyl acetate (10 μg/μL) appeared to be the activating compounds, eliciting equal responses from virgin females to that of the mixture, and higher responses of gravid females to that of the mixture, both of which were higher than the responses to hexane. Upwind and close flight responses of virgin males were lower than those of virgin and gravid females. In field trials, we verified that traps baited with ethyl butanoate (5 μg/μL) captured more moths than the other esters. Therefore, from the esters and concentrations tested, we recommend ethyl butanoate (5 μg/μL) for potential use as an attractant for G. molesta in orchards.     

Biological activity of Xanthium strumarium seed extracts on different cancer cell lines and Aedes caspius,Culex pipiens (Diptera: Culicidae)

Effects of methanol extracts of Xanthium strumarium on different cancer cell lines and on the mortality rates of Aedes caspius, Culex pipiens (Diptera: Culicidae) were investigated. Among the cell lines tested, the Jurkat cell line was the most sensitive to the methanol extract and ethyl acetate fraction, with reported LC₅₀ values of 50.18 and 48.73 μg/ml respectively. Conversely, methanol extracts were not that toxic to the A549 cell line though the toxicity increased on further purification. The percentage of growth inhibition was dose dependent for the methanol extract and ethyl acetate fraction. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The results showed that methanol extracts of plant seeds caused 100% mortality of mosquito larvae at a concentration of 1000 μg/ml after 24 h of treatment. The LC₅₀ and LC₉₀ values of X. strumarium were found to be 531.07 and 905.95 μg/ml against Ae. caspius and 502.32 and 867.63 μg/ml against Cx. Pipiens, respectively. From the investigations, it was concluded that the crude extract of X. strumarium showed a weak potential for controlling the larval instars of Ae. caspius and Cx. pipiens. However, on further purification the extract lost the larvicidal activity. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The ethyl acetate fraction investigated in this study appears to have a weak larvicidal activity but a promising cytotoxic activity. Future studies will include purification and investigation in further detail of the action of X. strumarium on Cancer Cell Lines and mosquitoes.     

Evaluation of antioxidant properties and total phenolic contents of some strains of microalgae

Antioxidant activities of both cells and extracellular substances were evaluated in 12 soil-isolated strains of microalgae according to FRAP and DPPH-HPLC assays. Their total phenolic contents were also determined by Folin–Ciocalteu method. Extractions were performed with hexane, ethyl acetate, and water. The results of FRAP assay showed that algal cells contained considerable amounts of antioxidants from 0.56 ± 0.06 to 31.06 ± 4.00 μmol Trolox g⁻¹ for Microchaete tenera hexane extract and Chlorella vulgaris water extract, respectively. In water fractions of extracellular substances, the antioxidants were from 1.30 ± 0.15 μmol Trolox g⁻¹ for Fischerella musicola to 73.20 ± 0.16 μmol Trolox g⁻¹ for Fischerella ambigua. Also, DPPH-HPLC assay represented high antioxidant potential of water fractions. The measured radical-scavenging activities of the studied microalgae were at least 0.15 ± 0.02 in Nostoc ellipsosporum cell mass to a maximum of 109.02 ± 8.25 in C. vulgaris extracellular substance. The amount of total phenolic contents varied in different strains of microalgae and ranged from zero in hexane extract to 19.15 ± 0.04 mg GAE g⁻¹ in C. vulgaris extracellular water fraction. Significant correlation coefficients between two measured parameters indicated that phenolic compounds were a major contributor to the microalgal antioxidant capacities.     

Anticariogenic and phytochemical evaluation of Eucalyptus globules Labill.

In the present study, in vitro anticariogenic potential of ethyl acetate, hexane and methanol and aqueous extracts of plant leaves of Eucalyptus globules Labill. were evaluated by using four cariogenic bacteria, Lactobacillus acidophilus, Lactobacillus casei, Staphylococcus aureus and Streptococcus mutans. Agar well diffusion method and minimum inhibitory concentration (MIC) were used for this purpose. The ethyl acetate extracted fraction of plant leaves showed good inhibitory effects against all selected bacteria. In Eucalyptus globules, hexane and ethyl acetate extracts found highly effective against, Lactobacillus acidophilus with MIC value of 0.031 and 0.062 mg/mL, respectively. Qualitative phytochemical investigation of above extracts showed the presence of alkaloids, phenolic compounds, steroids, cardiac glycosides and terpenes. Based on the MIC value and bioautography, ethyl acetate of plant leaf was selected for further study. Further investigation on the structure elucidation of the bioactive compound using IR, GC-MS and NMR techniques revealed the presence of alpha-farnesene, a sesquiterpene. Eucalyptus globules plant leaf extracts have great potential as anticariogenic agents that may be useful in the treatment of oral disease.     

Effect of oligogalacturonides on root length, extracellular alkalinization and O₂⁻-accumulation in alfalfa

The effects of an oligogalacturonic acid (OGA) pool on root length of intact alfalfa seedlings (Medicago sativa L.), on extracellular pH and on both extracellular and intracellular O₂⁻ dynamics were examined in this study. Lower OGA concentrations (25, 50 and 75 μg mL⁻¹) promoted root length, but 50 μg mL⁻¹ had a stronger effect in promoting growth, while the higher OGA concentration (100 μg mL⁻¹) had no significant effect. Extracellular alkalinization was tested only at concentrations higher than 50 μg mL⁻¹ OGA, showing that the response is determined not only by the specific size of OGA, but also by the concentration of OGA. The promoting effect of OGA on root growth at 25, 50 and 75 μg mL⁻¹ OGA concentrations in alfalfa root appeared to be unrelated to extracellular alkalinization. A possible explanation could be the induction of an O₂⁻ burst at non-toxic levels, which could drive directly or indirectly several processes associated with root elongation in 25, 50 and 75 μg mL⁻¹ OGA-treated seedlings. Analyses using confocal microscopy showed that the increase in the O₂⁻ generation, mainly in the epidermal cells, induced by 50 μg mL⁻¹ OGA could be related to the promoting effect on root growth. The combination of OGA with DPI allowed us to demonstrate that there are different O₂⁻-generating sources in the epidermal cells of the meristematic zone, likely NADPH oxidase and oxidases or oxido-reductase enzymes, insensitive to DPI, that maintain detectable O₂⁻ accumulation at 60 and 120 min of treatment. These results suggest that OGA induce an oxidative burst by several O₂⁻-generating sources in the active growth zones.     

A novel allelopathic substance, 13-epi-orthosiphol N,in Orthosiphon stamineus

Orthosiphon stamineus (Java tea) has been widely used as traditional herb and several bioactive compounds against animal cells have been isolated. However, no bioactive compound against plants has been reported. Therefore, we investigated possible allelopathic properties and substances in O. stamineus. Aqueous methanol extracts of O. stamineus inhibited root and hypocotyl growth of cress (Lepidium sativum) and lettuce (Lactuca sativa) seedlings. Increasing the extract concentration increased the inhibition, which suggests that O. stamineus may have allelopathic properties. When the extract was divided into an ethyl acetate and an aqueous fraction, the ethyl acetate fraction showed the stronger inhibitory effect. Thus, the ethyl acetate phase was further purified, and the main allelopathic substance was isolated and identified as 13-epi-orthosiphol N, a novel compound, by spectral data. 13-epi-Orthosiphol N inhibited root and hypocotyl growth of cress and lettuce at concentrations greater than 10 μmol/L. The concentrations required for 50% inhibition ranged from 41 to 102 μmol/L. These results suggest that 13-epi-orthosiphol N may be an allelochemical and main contributor to the growth inhibitory effect of O. stamineus and may have potential as a template for the development of new plant control substances.     

Characterization of inhibitory constituents of NO production from Catalpa ovata using LC-MS coupled with a cell-based assay

An effective screening method for inhibitors of NO production in natural products using LC-QTOF MS/MS coupled with a cell-based assay was proposed. The ethyl acetate fraction of Catalpa ovata exhibited a strong inhibitory effect on NO production in lipopolysaccharide-induced BV2 microglia cells. We attempted to identify the active constituents of C. ovata by using LC-QTOF MS/MS coupled with a cell-based assay. Peaks at approximately 14–15 min on the MS chromatogram were estimated to be the bioactive constituents. A new iridoid compound, 6-O-trans-feruloyl-3β-hydroxy-7-deoxyrehamaglutin A (4), and nine known compounds (1–3, 5–10) were isolated from the ethyl acetate fraction of C. ovata by repeated column chromatography. Compounds 3, 4, 5, 7, and 8 significantly attenuated lipopolysaccharide-stimulated NO production in BV2 cells. Our results indicate that LC-QTOF MS/MS coupled with a cell-based NO production inhibitory assay successfully predicted active compounds without a time-consuming isolation process.