Waveguiding and SERS Simplified Raman Spectroscopy on Biological Samples

Biomarkers detection at an ultra-low concentration in biofluids (blood, serum, saliva, etc.) is a key point for the early diagnosis success and the development of personalized therapies. However, it remains a challenge due to limiting factors like (i) the complexity of analyzed media, and (ii) the aspecificity detection and the poor sensitivity of the conventional methods. In addition, several applications require the integration of the primary sensors with other devices (microfluidic devices, capillaries, flasks, vials, etc.) where transducing the signal might be difficult, reducing performances and applicability. In the present work, we demonstrate a new class of optical biosensor we have developed integrating an optical waveguide (OWG) with specific plasmonic surfaces. Exploiting the plasmonic resonance, the devices give consistent results in surface enhanced Raman spectroscopy (SERS) for continuous and label-free detection of biological compounds. The OWG allows driving optical signals in the proximity of SERS surfaces (detection area) overcoming spatial constraints, in order to reach places previously optically inaccessible. A rutile prism couples the remote laser source to the OWG, while a Raman spectrometer collects the SERS far field scattering. The present biosensors were implemented by a simple fabrication process, which includes photolithography and nanofabrication. By using such devices, it was possible to detect cell metabolites like Phenylalanine (Phe), Adenosine 5-triphosphate sodium hydrate (ATP), Sodium Lactate, Human Interleukin 6 (IL6), and relate them to possible metabolic pathway variation.

Pharmacokinetic and tissue distributions study of adenosine, 4-hydroxybenzyl alcohol and Parishin C from Gastrodia elata extract in rats

The plant Gastrodia elata is a type of the orchid plant Gastrodia elata Bl. which contains glycosides, phenols, polysaccharides, sterols, and organic acids and a variety of active ingredients are proved to have certain pharmacological activities. To understand the process in the body of Gastridua elata, we used HPLC to study pharmacokinetics and tissue distributions of adenosine, 4-hydroxybenzyl alcohol and Parishin C in rats. The results showed that the three ingredients could be detected in plasma and different organizations at various time points. There was no significant difference in systemic clearance at three ingredients and it may be show that the three ingredients distributed (0.475±0.025, 0.518±0.033, 0.699±0.051) quickly and eliminated (5.37±0.87, 4.54±0.69, 5.34±0.82) slowly in plasma. There was the highest content of adenosine in spleen, followed by liver and lung. The highest content of 4-hydroxybenzylacohol in liver, and was higher in spleen. Parishin C was highest in heart, followed by liver and spleen. It is obvious that the contents of three ingredients are all higher in liver. The trends of the three ingredients' contents in G. rhizome extract were consistent with the contents in the plasma after intravenous administration.

Anticoagulant Activity of Low-Molecular Weight Compounds from Heterometrus laoticus Scorpion Venom

Scorpion venoms are complex polypeptide mixtures, the ion channel blockers and antimicrobial peptides being the best studied components. The coagulopathic properties of scorpion venoms are poorly studied and the data about substances exhibiting these properties are very limited. During research on the Heterometrus laoticus scorpion venom, we have isolated low-molecular compounds with anticoagulant activity. Determination of their structure has shown that one of them is adenosine, and two others are dipeptides LeuTrp and IleTrp. The anticoagulant properties of adenosine, an inhibitor of platelet aggregation, are well known, but its presence in scorpion venom is shown for the first time. The dipeptides did not influence the coagulation time in standard plasma coagulation tests. However, similarly to adenosine, both peptides strongly prolonged the bleeding time from mouse tail and in vitro clot formation in whole blood. The dipeptides inhibited the secondary phase in platelet aggregation induced by ADP, and IleTrp decreased an initial rate of platelet aggregation induced by collagen. This suggests that their anticoagulant effects may be realized through the deterioration of platelet function. The ability of short peptides from venom to slow down blood coagulation and their presence in scorpion venom are established for the first time. Further studies are needed to elucidate the precise molecular mechanism of dipeptide anticoagulant activity.

Determination of the Main Nucleosides and Nucleobases in Natural and Cultured Ophiocordyceps xuefengensis

Ophiocordyceps xuefengensis, a recently described species of Ophiocordycepsthat is associated with the larvae of Phassusnodus (Hepialidae) in the living root or trunk of the medicinal plant Clerodendrumcyrtophyllum, isthe largest known Cordycepsspecies and is recognized as a desirable alternative for natural Ophiocordycepssinensis. This study investigated the main nucleosides and nucleobases in natural and cultured Ophiocordycepsxuefengensis. The contents of the nucleosides and nucleobases in the natural and cultured samples were determined by reverse phase HPLC. The highest concentration of adenosine was found in the natural fruit body and the cultured stroma, with almost no adenosine in the cadaver of Phassusnodus. The contents of adenine, guanosine, uridine and uracil in the cultured mycelium were significantly higher than those in the natural sample. Inosine was only detected in the natural samples. Thymidine and 2-deoxyadenosine were only found in the cadaver of Phassusnodus. Cordycepin was not detected in the five samples examined. These results suggested that the cultured mycelium and cultured stroma of Ophiocordycepsxuefengensis might be a promising substitute for natural O. xuefengensis.

Label-free electrochemical aptasensor for adenosine detection based on cascade signal amplification strategy

In this work, a simple and highly sensitive label-free electrochemical aptasensor for adenosine detection was developed based on target-aptamer binding triggered nicking endonuclease-assisted strand-replacement DNA polymerization and rolling circle amplification (RCA) strategy. The magnetic beads (MB) probe, which was attached the aptamer of adenosine and mDNA, was firstly fabricated. In the presence of adenosine, mDNA was released from MB upon recognition of the aptamer to target adenosine. The released mDNA as the primer activated autonomous DNA polymerization/nicking process and accompanied by the continuous release of replicated DNA fragments. Subsequently, numerous released DNA fragments were captured on the working electrode, and then as initiators to trigger the downstream RCA process leading to the formation of a long ssDNA concatemer for loading large amounts of Ru(NH₃)₆³⁺. Therefore, a conspicuously amplified electrochemical signal through the developed dual-amplification strategy could be achieved. This method exhibited a high sensitivity toward adenosine with a detection limit of 0.032nM. Also, it exhibited high selectivity to different nucleoside families and good reproducibility. This design opens new horizons for integrating different disciplines, presenting a versatile tool for ultrasensitive detecting organic small molecules in medical research and clinical diagnosis.

Hints of Western Medicine from Chinese Medicine

As a biochemist, I have been studying lipolytic and lipogenic pathways in fat cells since 1963. In 1966, I proposed a hormone-sensitive substrate theory in which catecholamines might not act on lipase but on substrate during their lipolytic processes. The lipolytic and lipogenic pathways are negative and positive processes in triglyceride content of fat cells. Insulin inhibits the negative process (lipolysis) and stimulates the positive process (lipogenesis from glucose). On the other hand, catecholamine stimulates the negative process and inhibits the positive one. These hormones discriminate the negative and positive rules and regulate opposite ways. We tried to find these hormone-like substances in various natural products. We isolated tea saponins, chitosan, and others as insulin-like substances and dimethyl-xanthine as a catecholamine-like one. It is well known that extracellular fluid pH changes from 7.4 to 6.8. Reduction of the pH from 7.4 causes insulin resistance. Insulin failed to stimulate glucose uptake at pH 7.0 of the extracellular fluid. We found minus ions, which stimulated lipogenesis from glucose by raising extracellular fluid pH to 7.4. These are our approaches to find functional substances that prevent lifestyle-related diseases.

High-throughput sequencing for 1-methyladenosine (m(1)A) mapping in RNA

Detection and mapping of modified nucleotides in RNAs is a difficult and laborious task. Several physico-chemical approaches based on differential properties of modified nucleotides can be used, however, most of these methods do not allow high-throughput analysis. Here we describe in details a method for mapping of rather common 1-methyladenosine (m(1)A) residues using high-throughput next generation sequencing (NGS). Since m(1)A residues block primer extension during reverse transcription (RT), the accumulation of abortive products as well as the nucleotide misincorporation can be detected in the sequencing data. The described library preparation protocol allows to capture both types of cDNA products essential for further bioinformatic analysis. We demonstrate that m(1)A residues produce characteristic arrest and mismatch rates and combination of both can be used for their detection as well as for discrimination of m(1)A from other modified A residues present in RNAs.

Four process-related potential new impurities in ticagrelor: Identification, isolation, characterization using HPLC, LC/ESI-MS(n), NMR and their synthesis

Five process-related impurities were detected in the range of 0.08-0.22% in ticagrelor laboratory batches by HPLC and LC-MS methods. These impurities were named as TIC Imp-I, -II, -III, -IV and -V. Four of these impurities, TIC Imp-I to -IV were unknown and have not been reported previously. Based on LC-ESI/MS(n) study, the chemical structures of new impurities were presumed as (1S,2S,3S,5S)-3-(2-hydroxyethoxy)-5-(7-amino-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d] pyrimidin-3-yl)cyclopentane-1,2-diol (TIC Imp-I), (1S,2S,3S,5S)-3-(7-((1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino)-5-(propylsulfinyl)-3H-[1,2,3]triazolo [4,5-d]pyrimidin-3-yl)-5-(2-hydroxyethoxy)cyclopentane-1,2-diol (TIC Imp-II), (1S,2R,3S,4S)-4-(7-((1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino)-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl)cyclopentane-1,2,3-triol (TIC Imp-III) and (3S,5S)-3-(7-((1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino)-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl)-5-(2-hydroxyethoxy)cyclopentane-1,2-diol (TIC Imp-IV). The unknown impurities were isolated from enriched crude sample by column chromatography and preparative HPLC. The complete spectral analysis, MS, 1D NMR ((1)H, (13)C and DEPT), 2D NMR (HSQC and HMBC) and IR confirmed the proposed chemical structures of impurities. Identification, isolation, structural characterization, prospects for the formation of impurities and their synthesis were first reported in this paper.

A fluorescent aptasensor using double-stranded DNA/graphene oxide as the indicator probe

We developed a fluorescent aptasensor based on the making use of double-stranded DNA (dsDNA)/graphene oxide (GO) as the signal probe and the activities of exonuclease I (Exo I). This method takes advantage of the stronger affinity of the aptamer to its target rather than to its complementary sequence (competitor), and the different interaction intensity of dsDNA, mononucleotides with GO. Specifically, in the absence of target, the competitor hybridizes with the aptamer, preventing the digestion of the competitor by Exo I, and thus the formed dsDNA is adsorbed on GO surface, allowing fluorescence quenching. When the target is introduced, the aptamer preferentially binds with its target. Thereby, the corresponding nuclease reaction takes place, and slight fluorescence change is obtained after the introduction of GO due to the weak affinity of the generated mononucleotides to GO. Adenosine (AD) was chosen as a model system and tested in detail. Under the optimized conditions, smaller dissociation constant (Kd, 311.0 µM) and lower detection limit (LOD, 3.1 µM) were obtained in contrast with traditional dye-labeled aptamer/GO based platform (Kd=688.8 µM, LOD=21.2 µM). Satisfying results were still obtained in the evaluation of the specificity and the detection of AD in human serum, making it a promising tool for the diagnosis of AD-relevant diseases. Moreover, we demonstrated the effect of the competitor on the LOD, and the results reveal that the sensitivity could be enhanced by using the rational competitor. The present design not only constructs a label-free aptamer based platform but also extends the application of dsDNA/GO complex in biochemical and biomedical studies.

Cordycepin and N6-(2-hydroxyethyl)-adenosine from Cordyceps pruinosa and their interaction with human serum albumin

Cordyceps pruinosa (CP) is often used as Traditional Chinese Medicine, but the substance basis of its medicinal properties is unclear. In this study, two compounds were isolated from CP cultures by column chromatography, and identified as cordycepin and N6-(2-hydroxyethyl)-adenosine (HEA) by Nuclear Magnetic Resonance. In order to understand the efficacy of these two substances as potential therapeutic agents, it is necessary to explore their binding with proteins. The molecular mechanisms of interaction between cordycepin, HEA and human serum albumin (HSA) were studied using UV and fluorescence spectroscopy. The bingding constants between HSA and cordycepin were 4.227, 3.573 and 3.076 × 10(3)·at 17, 27 and 37°C respectively, and that of HSA and HEA were 27.102, 19.409 and 13.002 × 10(3)·at the three tempretures respectively. Both cordycepin and HEA can quench the intrinsic fluorescence of HSA via static quenching, and they can bind with HSA to form complexes with a single binding site. The interaction forces between cordycepin and HSA were determined as electrostatic and hydrophobic, and those of HEA and HSA were hydrogen bonding and van der Waals forces. Using Foster's equation, the distance between fluorophores of cordycepin and HSA, and HEA and HSA are estimated to be 5.31 nm and 4.98 nm, respectively. In this study, cordycepin was isolated for the first time from CP, and will provide a new source of cordycepin and expand the use of this taxon. The interaction mechanisms between cordycepin and HSA was studied for the first time, which will provide a useful guide for the clinical application of cordycepin. The pharmacological importance of this study is to understand the interaction of HSA with cordycepin and HEA, which will be essential for the future designing of drugs based on the two compounds.

Recent advances in application of biosensors in tissue engineering

Biosensors research is a fast growing field in which tens of thousands of papers have been published over the years, and the industry is now worth billions of dollars. The biosensor products have found their applications in numerous industries including food and beverages, agricultural, environmental, medical diagnostics, and pharmaceutical industries and many more. Even though numerous biosensors have been developed for detection of proteins, peptides, enzymes, and numerous other biomolecules for diverse applications, their applications in tissue engineering have remained limited. In recent years, there has been a growing interest in application of novel biosensors in cell culture and tissue engineering, for example, real-time detection of small molecules such as glucose, lactose, and H2O2 as well as serum proteins of large molecular size, such as albumin and alpha-fetoprotein, and inflammatory cytokines, such as IFN-g and TNF-α. In this review, we provide an overview of the recent advancements in biosensors for tissue engineering applications.

[Alkaloids from cervi cornu pantotrichum and its effect on murine splenocytes proliferation]

OBJECTIVE

To study the alkaloids of Cervi Cornu Pantotrichum and its effect on murine splenocytes proliferation.

METHODS

The constituents isolation and purification from Cervi Cornu Pantotrichum was carried out by reported column chromatography including Sephadex LH-20 and MCI (CHP20P) and their structures were elucidated on the basis of spectral compounds. The method of MTT was used to examine the effects of eight alkaloids and total alkaloids content (TAC) of Cervi Cornu Pantotrichum on murine splenocytes proliferation.

RESULTS

Eleven compounds were isolated from Cervi Cornu Pantotrichum, and their structures were identified as follows: uracil (1), hypoxanthine (2), uridine (3) inosine (4), guanosine (5), 2'-deoxyguanosine (6), guanine (7), thymidine (8), thymine (9), cytidine (10) and adenosine (11). By the experiment of murine splenocytes proliferation activity in vitro, the results showed that the total alkaloids, uracil and adenosine had significantly promoted the proliferation of mouse spleen cells.

CONCLUSION

Compounds 4 - 11 are isolated from Cervi Cornu Pantotrichum for the first time. The total alkaloids is one of the material basis of immunomodulatory effects of Cervi Cornu Pantotrichum, and uracil and adenosine are the most active.

Neurochemical measurement of adenosine in discrete brain regions of five strains of inbred mice

Adenosine (ADO), a non-classical neurotransmitter and neuromodulator, and its metabolites adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP), have been shown to play an important role in a number of biochemical processes. Although their signaling is well described, it has been difficult to directly, accurately and simultaneously quantitate these purines in tissue or fluids. Here, we describe a novel method for measuring adenosine (ADO) and its metabolites using high performance liquid chromatography with electrochemical detection (HPLC-ECD). Using this chromatographic technique, we examined baseline levels of ADO and ATP, ADP and AMP in 6 different brain regions of the C57BL/6J mouse: stratum, cortex, hippocampus, olfactory bulb, substantia nigra and cerebellum and compared ADO levels in 5 different strains of mice (C57BL/6J, Swiss-Webster, FVB/NJ, 129P/J, and BALB/c). These studies demonstrate that baseline levels of purines vary significantly among the brain regions as well as between different mouse strains. These dissimilarities in purine concentrations may explain the variable phenotypes among background strains described in neurological disease models.

[Study on the chemical constituents of the PTP 1B inhibitory effective parts of Paeoniae Rubra Radix]

OBJECTIVE

To study the chemical constituents of the PTP 1B inhibitory effective parts of Paeoniae Rubra Radix.

METHODS

The effective part of Paeoniae Rubra Radix was enriched by Sephadex LH-20. Compounds were isolated by various column chromatography and their structures were elucidated through spectroscopic analysis.

RESULTS

Thirteen compounds were identified as: benzoylpaeoniflorin(1), albiflorin(2), paeoniflorigenone(3), methyl gallate(4), adenosine(5),2-amino adenosine(6), 3,3'-Di-O-methylellagic acid(7), 3,3',4-trimethyl ellagic acid(8), dihydrokaempferol(9), glycerol(10), dibutyl phthalate(11).

CONCLUSION

Compounds 5-11 are obtained from this plant for the first time.

[Isolation and structure elucidation of chemical constituents from Pinellia ternata]

OBJECTIVE

To isolate and identify the chemical constituents of ethanol extract of Pinellia ternata.

METHODS

The constituents were isolated by silica-gel, Sephadex LH-20 chromatography and HPLC techniques. The structures were identified by spectroscopic analysis including 2D NMR techniques and chemical properties.

RESULTS

Nine compounds were obtained and identified as uridine (1), 5'-S-methyl-5'-thioadenosine (2), adenine (3), chrysophanol (4), 5-hydroxymethylfurfural (5), nicotinamide (6), (2S)-1-O-(9Z, 12Z-octadecadienoyl)-3-O-beta-galactopyranosylglycerol (7), daucosterol (8), beta-sitosterol (9).

CONCLUSION

Compounds 2, 6, 7 are isolated from this plant for the first time.

Purification and characterization of antioxidant components from the fruiting bodies of Pleurotus abalonus including 9-beta-d-ribofuranosidoadenine, 5'-deoxy-5'-(methylthio)adenosine, and a triterpenoid

Although Pleurotus abalonus is a well-known edible mushroom in Asia, there is a dearth of information on its antioxidant activity. The present report is the first one focused on the purification and characterization of 9-beta-d-ribofuranosidoadenine (ADO), 5'-deoxy-5'-(methylthio) adenosine (MTA) and a triterpenoid complex from P. abalonus. Different antioxidant activities including inhibitory effects on hemolysis and lipid peroxidation in brain and kidney homogenates as well as significant synergistic effect on scavenging of hydroxyl radicals were demonstrated, which lays a foundation for the development of P. abalonus as a natural antioxidant applied in medicine.

Epimeric methylsulfinyladenosine derivatives from the marine ascidian Herdmania momus

Investigation of the secondary metabolites of the ascidian Herdmania momus led to the isolation and characterization of four new nucleoside derivatives (1-4). Structural studies showed that these derivatives represent a series of rare methylsulfinyladenosine derivatives of interconvertible transesterification isomers and/or sulfinyl epimers. The antiviral activities of these rare nucleosides were evaluated against a series of human pathogenic viruses.

Hypotensive and cardio-chronotropic constituents of Tinospora crispa and mechanisms of action on the cardiovascular system in anesthetized rats

ETHNOPHARMACOLOGICAL RELEVANCE

Tinospora crispa has been used in folkloric medicine for the control of blood pressure. We previously found that an extract of Tinospora crispa stems decreased the mean arterial blood pressure (MAP) with a transient decrease, followed by an increase in the heart rate (HR) in rats.

AIM OF THE STUDY

To identify the active components of the Tinospora crispa extract and investigate the mechanisms of action on blood pressure and heart rate in anesthetized rats.

MATERIALS AND METHODS

The active components of Tinospora crispa extract were separated by column chromatography and a preparative HPLC. The effects and mechanisms of the active compounds on blood pressure and heart rate were studied in anesthetized, normal and reserpinized rats in vivo.

RESULTS

5 active compounds: adenosine, uridine, salsolinol, higenamine and tyramine were isolated. Adenosine decreased MAP and HR and this effect was inhibited by DMPX (A(2A) adenosine receptor antagonist). Uridine increased MAP and decreased HR and this was inhibited by suramin but not by DMPX. Salsolinol decreased the MAP and HR and this was inhibited by phentolamine but not by ICI-118,551 (β(2)-adrenoceptor antagonist) or atropine. In reserpinized rats, salsolinol had a hypertensive effect that was inhibited by prazosin and phentolamine, but not by atenolol, and caused an increase in HR that was inhibited by atenolol, but not by prazosin or phentolamine. Higenamine decreased the MAP with an increase in HR. The hypotensive effect was inhibited by ICI-118,551 or atenolol, whereas the increase in HR was not inhibited by ICI-118,551. Atenolol inhibited the increase in HR at a small dosage of higenamine but potentiated it at a higher dosage. In reserpinized rats, a small dosage of higenamine tended to potentiate the effect but at a higher dosage it caused inhibition. ICI-118,551 significantly inhibited this hypotensive effect. Tyramine caused an increase in MAP and HR and these effects almost disappeared in reserpinized rats.

CONCLUSIONS

The results demonstrate that these 5 compounds from Tinospora crispa acted in concert on the cardiovascular system of anesthetized rats. Salsolinol, tyramine and higenamine acted via the adrenoreceptors, whereas uridine and adenosine acted via the purinergic adenosine A(2) and P(2) receptors to decrease blood pressure with a transient decrease of HR followed by an increase.

[Constituents from the leaves of Aquilaria sinensis]

OBJECTIVE

To study the chemical constituents of the leaves of Aquilaria sinensis.

METHOD

The compounds were isolated and purified by the methods of solvent extraction and chromatographic technique, and their structures were identified on the basis of the analyses of spectral data.

RESULT

Thirty-three compounds were obtained. Among them, twelve compounds were identified as 5-hydroxyl-7,4'-dimethoxyflavone (1), acacetin (2), luteolin (3), genkwanin (4), yuankanin (genkwanin-5-O-beta-D-primeveroside, 5), adenosine (6), genkwanin-5-O-beta-D-glucopyranoside (7), hypolaetin-7-O-beta-D-glucopyranoside (8), hypoxanthine (9), uracil (10), 8-C-beta-D-galactopyranosylisovitexin (11), and 4-(1,2,3-trihydroxypropyl) -2,6-dimethoxyphenyl-1-O-beta-D-glucopyranoside (12), respectively.

CONCLUSION

All compounds except for 1, 3 and 4 were isolated from the leaves of A. sinensis for the first time.

[Chemical constituents from Corydalis yanhusuo]

OBJECTIVE

To investigate the chemical constituents of Corydalis yanhusuo.

METHOD

The compounds were isolated and purified by column chromatography over macroporous absorption resin, silica gel, and Sephadex LH-20. Their structures were elucidated on the basis of physicochemical properties and spectral data.

RESULT

22 compounds were isolated and identified as corydaline (1), tetrahydropalmatine (2), protopine (3), tetrahydrocorysamine (4), tetrahydrocoptisine (5) , tetrahydroberberine (6), tetrahydrocolumbamine (7), noroxyhydrastine (8), dehydrocorydaline (9), glaucine (10), columbamine (11), 8-oxocoptisine (12), 13-methyl-columbamine (13), coptisine (14), palmatine (15), herberine (16), oxoglaucine (17), 13-methyl-palmatrubine (18), dehydrocorybulbine (19), stepharanine (20), adenosine (21), and N5 -acetylornithine (22).

CONCLUSION

Compounds 13, 20, 21, and 22 were isolated from this plant for the first time.

Simultaneous determination of different endogenetic plant growth regulators in common green seaweeds using dispersive liquid-liquid microextraction method

A simple and rapid HPLC-based method was developed for simultaneous determination of major classes of plant growth regulators (PGRs) in Monostroma and different species of Ulva. The plant growth regulators determined included gibberellic acid (GA(3)), indole-3-acetic acid (IAA), abscisic acid (ABA), indole-3-butyric acid (IBA), salicylic acid and kinetin riboside (KR) and their respective elution time was 2.75, 3.3, 3.91, 4.95, 5.39 and 6.59 min. The parameters optimized for distinct separation of PGRs were mobile phase (60:40 methanol and 0.6% acetic acid in water), column temperature (35°C) and flow rate (1ml/min). This method presented an excellent linearity (0.2-100μg/ml) with limit of detection (LOD) as 0.2μg/ml for ABA, 0.5μg/ml for KR and salicylic acid, and 1μg/ml for IAA, IBA and GA(3). The precision and accuracy of the method was evaluated after inter and intra day analysis in triplicates. The effect of plant matrix was compensated after spiking and the resultant recoveries estimated were in the range of 80-120%. Each PGR thereby detected were further characterized by ESI-MS analysis. The method optimized in this study determined IBA along with IAA for the first time in the seaweed species investigated except Ulva linza where the former was not detected. In all the species studied, ABA level was detected to be the highest while kinetin riboside was the lowest. In comparison to earlier methods of PGR analysis, sample preparation and analysis time were substantially reduced while allowing determination of more classes of PGRs simultaneously.

[Polar constituents of Mosla chinensis]

OBJECTIVE

To study polar constituents of Mosla Chinensis.

METHOD

The constituents were isolated and purified by various chromatographic techniques and their structures were elucidated by physico-chemicalproperties and spectroscopic data.

RESULT

Seven glucosides were obtained and their structures were identified as 4-hydroxy-2,6-dimethoxyphenyl-beta-D-glucopyranoside (1), 4-hydroxy-3,5-dimethoxyphenyl-beta-D-glucopyranoside (2), 3, 4, 5-trimethoxypheyl-beta-D-glucopyranoside (3), 3-hydroxyestragole-beta-D-glucopyranoside (4), (6S,9R) -roseoside (5), adenosine (6), and p-hydroxybenzoicacid glucoside (7).

CONCLUSION

All compounds were isolated from the genus Mosla for the first time.

Tyrosinase inhibition by water and ethanol extracts of a far eastern sea cucumber, Stichopus japonicus

BACKGROUND

Tyrosinase plays a key role in hyperpigmentaion and enzymatic browning. The present study was aimed at investigating the inhibitory effects of water and 70% aqueous ethanol extracts of Stichopus japonicus, a sea cucumber long consumed as a tonic food and traditional medicine, on the diphenolase activity of tyrosinase.

RESULTS

In the tyrosinase inhibition study, high-performance liquid chromatography completely separated L-3,4-dihydroxyphenylalanine and dopachrome from other compounds present in the extracts, and provided more reliable results than the commonly used spectrophotometry. The ethanol extract (IC(50)=0.49-0.61 mg mL(-1)) showed higher inhibitory activity than the water extract (IC(50)=1.80-1.99 mg mL(-1)). Enzyme inhibition by the extracts was reversible and of mixed type. For both extracts, the dissociation constants for binding to free enzyme were significantly smaller than those for binding to enzyme-substrate complex. Ethyl-α-D-glucopyranoside (IC(50)=0.19 mg mL(-1)), isolated for the first time from sea cucumber, and adenosine (IC(50)=0.13 mg mL(-1)), were identified as key tyrosinase inhibitors.

CONCLUSION

The sea cucumber extracts were demonstrated to possess considerable inhibitory potency against the diphenolase activity of tyrosinase, suggesting that the sea cucumber may be a good source of safe and effective tyrosinase inhibitors.

[Studies on the chemical constituents of the herb of Antenoron filiforme]

OBJECTIVE

To study the chemical constituents of the herb of Antenoron filiforme.

METHODS

The constituents were separated by column chromatography and their structures were elucidated by spectral data analyses.

RESULTS

Eleven compounds were isolated from the ethanol extract of A. filiforme and identified as, bronane-5-hydroxy-2-O-beta-D-glucopyranoside (I), adenosine (II), bonaroside (III), rhamnetin (IV), hyperoside (V), rhamnetin-3-O-beta-D-galactopyranoside (VI), kaempferol-3, 7-O-bis-alpha-L-rhamnopyranoside (VII), stigmasterol (VIII), nonacosanoic acid (IX), daucosterol (X), 3beta-sitosterol (XI).

CONCLUSION

All compounds are obtained from A. filiforme for the first time.

Isolation of adenosine, iso-sinensetin and dimethylguanosine with antioxidant and HIV-1 protease inhibiting activities from fruiting bodies of Cordyceps militaris

According to previous studies, a close relationship between oxidative stress and AIDS suggests that antioxidants might play an important role in the treatment of AIDS. Cordyceps militaris was selected from nine edible mushrooms by assay of inhibition of erythrocyte hemolysis. Macroporous adsorption resin and HPLC were used to purify three micromolecular compounds named L3a, L3b and L3c. L3a was identified to be adenosine with the molecular formula C(10)H(13)N(5)O(4); L3b was 6,7,2',4',5'-pentamethoxyflavone with the molecular formula C(20)H(20)O(7), and L3c was dimethylguanosine with the molecular formula C(12)H(17)N(5)O(5). The compound 6,7,2',4',5'-pentamethoxyflavone was first isolated from C. militaris. The assay of inhibition of HIV-1 protease (HIV-1 PR) was based on the fact that the expression of this enzyme can inhibit the growth of E. coli. This is a new screening system for HIV-1 PR inhibitors. Both L3a and L3b showed high inhibition to HIV-1 PR. These compounds could be new anti-HIV-1 PR drugs.

A dual platform for selective analyte enrichment and ionization in mass spectrometry using aptamer-conjugated graphene oxide

This study demonstrates the use of aptamer-conjugated graphene oxide as an affinity extraction and detection platform for analytes from complex biological media. We have shown that cocaine and adenosine can be selectively enriched from plasma samples and that direct mass spectrometric readouts can be obtained without a matrix and with greatly improved signal-to-noise ratios. Aptamer-conjugated graphene oxide has clear advantages in target enrichment and in generating highly efficient ionization of target molecules for mass spectrometry. These results demonstrate the utility of the approach for analysis of small molecules in real biological samples.

[Studies on the chemical constituents from aerial parts of Gynura divaricata]

OBJECTIVE

To study the chemical constituents from aerial parts of Gynura divaricata.

METHODS

The constituents were isolated on silica gel column chromatography, preparative TLC and Sephadex LH-20 column chromatography, identified by physicochemical properties and the structures were elucidated by spectral analysis.

RESULTS

10 compounds were isolated and identified as 2-(1', 2', 3', 4'-tetrahydroxybutyl)-6-(2", 3", 4"-trihydroxybutyl)-pyrazine (1), 2-(1', 2', 3', 4'-tetrahydroxybutyl)-5-(2", 3", 4"-trihydroxybutyl) -pyrazine (2), nicotinic acid (3), 5-hydroxy-picolinic acid(4), methyl-5-hydroxy-2- pyridinecarboxylate (5), adenosine (6), uridine (7), stigmasterol-5-O- beta-D-glucoside (8), dibutyl terephthalate (9), methyl chlorogenate (10).

CONCLUSION

Compounds 1, 2, 5, 9, 10 are obtained from this genus for the first time, Compounds 3, 4 are obtained from this plant for the first time.

[The preparative method for 2-fluoroadenosine synthesis]

The preparative method for the synthesis of 2-fluoroadenosine starting from commercially available guanosine was developed. It included the intermediate formation of 2-amino-6-azido-9-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)purine, which was isolated exclusively in the tetrazolo[5,1-i]-form {5-amino-7-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-7H-tetrazolo[5,1-i]purine}. The latter compound was converted by the Schiemann reaction to 6-azido-2-fluoro-9-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)purine, which was isolated at an 80% yield after careful optimization of the process. The IR and 1H NMR spectroscopy data indicated the 6-azido-2-fluoropurine structure of the aglycone. The catalytic reduction of the azido group in 6-azido-2-fluoro-9-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)purine to the amino moiety and the subsequent deacetylation by the routine procedure resulted in 2-fluoroadenosine at a total yield of 74%.

Adenosine, an identified active component from the Driselase-treated fraction of rice bran, is effective at improving metabolic syndrome in stroke-prone spontaneously hypertensive rats

In the present study, we isolated and identified an active component from the Driselase-treated fraction and investigated its effect by acute and chronic oral administration on hypertension, lipid, and glucose metabolism in stroke-prone spontaneously hypertensive rats. The active component was identified as adenosine and improves hypertension after single oral administration. Rats who were 10 weeks old were divided into control and adenosine groups and were administered water or water with adenosine (10 mg/L), respectively, for 3 weeks. Hypertension and plasma lipid, nitric oxide, insulin, leptin, adiponectin levels, and glucose metabolism were significantly improved in the adenosine group. The mRNA expression levels of genes involved in lipid and glucose metabolism were altered in the adenosine group. Single oral administration of adenosine (10 mg/kg body weight) improved hypertension and plasma triglyceride, glucose, and nitric oxide levels 2 h after administration. In conclusion, oral acute and chronic administration of adenosine are beneficial and improve the metabolic syndrome-related disease parameters.

[Studies on chemical constituents of Tylopilus plumbeoviolaceus]

OBJECTIVE

To study the chemical constituents of Tylopilus plumbeoviolaceus.

METHODS

The compounds were isolated by silica gel column chromatography, and their structures were elucidated by spectral methods.

RESULTS

Five compounds were isolated and identified as ergosterol (I), ergosterol 5a,8a-peroside (II), ergothioneine (III), adenosine (IV), uracil (V).

CONCLUSION

All these compounds are obtained from this high fungus for the first time.

Immunomodulatory effect of Antrodia camphorata mycelia and culture filtrate

AIM OF THE STUDY

Antrodia camphorata, a precious folkloric medicinal mushroom, has been used to treat tumorigenic diseases in Taiwan. This study was to investigate the innate immunity augmentation effects of different fractions prepared from hot water extracts of submerged cultured Antrodia camphorata (AC).

MATERIALS AND METHODS

The cytokine induction potency of AC fraction in diluted peripheral blood culture was measured by ELISA. The effects of AC fraction on phagocytic activity and CD11b expression were measured by the ingestion of FITC-labeled Escherichia coli and by labeling with PE-labeled CD11b monoclonal antibody, respectively, using flow cytometry. The molecular mass of hot water-soluble polysaccharides and content of adenosine in AC fraction were determined by gel permeation chromatography (GPC) and HPLC, respectively.

RESULTS

The mycelia fraction, Fr. M II, and culture filtrate fractions, Fr. E II and Fr. E III, showed the strongest TNF-alpha and IL-6 induction effect as a function of their concentration. These fractions (20mug/ml) also showed marked activity in enhancing phagocytosis in human polymorphonuclear neutrophils (PMN) and monocytes. In parallel, the expression of CD11b, an early marker of PMN activation, was also up-regulated dose-dependently. Composition analysis suggested that immunomodulatory effect of mycelia is mainly attributed to the 10-20kDa polysaccharides and adenosine.

CONCLUSIONS

These results provide evidences that Antrodia camphorata can modulate innate immunity and may serve as an adjuvant for tumor treatment.

[Study on HPLC fingerprint characteristic analysis of Cordyceps sinensis and its similar products]

OBJECTIVE

To study on HPLC fingerprint characteristic analysis of Cordyceps sinensis and its similar products.

METHODS

To determinate 13 samples of Cordyceps sinensis and its similar products by HPLC, and analyze the HPLC results with similar appraisal method and graphical methods of multivariate sample in two dimensional plane such as the methods of profile, radar chart and constellation graph.

RESULTS

The similar appraisal method might synthesize the similar degree in quantification, while the graphical methods such as profile graph, radar chart and constellation graph could show more details about the classification and the characteristic of varieties directly.

CONCLUSIONS

We recommend the combined application of similar appraisal method and the graphical methods due to its advantages on the judgment and characteristic analysis of fingerprint.

Heterocyclic compounds from Chrysanthemum coronarium L. and their inhibitory activity on hACAT-1, hACAT-2, and LDL-oxidation

The aerial parts of Chrysanthemum coronarium L. were extracted with MeOH, and the concentrated extract was partitioned using EtOAc, n-BuOH, and H(2)O, successively. Repeated column chromatography of the EtOAc and n-BuOH fractions gave a new heterocycle, 5,5'-dibuthoxy-2,2'-bifuran (1) along with five known compounds: methyl trans-ferulate (2), prunasin (3), sambunigrin (4), pterolactam (5), and adenosine (6), which were identified by several spectroscopic methods including NMR and MS. This paper is the first report on the isolation of these compounds from C. coronarium L. The IC(50) values of compound 1 for human Acyl-CoA:cholesterol acyltransferase (hACAT)-1 and hACAT-2 were 0.16 mM and 0.19 mM, respectively. Compound 2 inhibited low-density lipoprotein (LDL) oxidation with an IC(50) value of 7.7 microM.

Purification of a dimethyladenosine compound from silkworm pupae as a vasorelaxation substance

To identify the active substance in the male silkworm pupae that strengthens men's vitality, the vasorelaxation activity was determined by measuring the vascular endothelial nitric oxide (eNO) produced in calf pulmonary artery endothelial (CPAE) cells treated with extracts from the pupae. Dried silkworm male pupae were extracted with ethanol and suspended in water, then partitioned with hexane, chloroform, ethylacetate, and butanol, sequentially. Among these fractions, the aqueous fraction had maximal NO production (156.87 microM/200 microl well, 10 mg/ml) and minimal cytotoxicity (IC50 362.3 mg/ml). The vasorelaxation substances (VAS) from the aqueous fraction were isolated by a combination of gel filtration and anion-exchange chromatography on DEAE Sephadex A-25 and reverse phase-HPLC. Their chemical structures were determined on the basis of their spectroscopic parameters of EI-MS, MALDI-TOF MS, 1H and 13C NMR, 1H-1H COSY, and GC-MS spectral data. The active substance was subsequently identified as a dimethyladenosine and dimethyladenosine-5'-L-arabinose that has phosphodiesterase (PDE) inhibition activity. This compound was shown to inhibit PDE4 activity in a dose-dependent manner. Also, it inhibited the PDE5 activity of cyclic-GMP-specific PDE5 enzyme. These results imply that dimethyladenosine may be a lead compound for the development and improvement of vasculogenic impotence drugs through phosphodiesterase inhibition and NO production in endothelial cells.

[Studies on chemical constituents of the seeds of Allium cepa]

OBJECTIVE

To study the chemical constituents from the seeds of Allium cepa L., the constituents of the seeds of Allium cepa L.

METHODS

To isolate and purify by silica gel, macroporous resin HP-20, Sephadex LH-20, RP-18 column.

RESULTS

Seven compounds were isolated from the EtOH extract of the seeds of Allium cepa., their structures were elucidated by physico-chemical properties and spectroscopic analysis as tianshic acid (I), N-trans-feruloyl tyramine (II), beta-sitosterol-3 beta-glucopyranoside-6'-palmitate (III), sitosterol (IV), daucosterol (V), tryptophane (VI), adenine riboside (VI).

CONCLUSION

Compounds V-VIII are obtained from this plant for the first time, compounds I-IV are isolated from the genus Allium for the first time.

[Studies on the chemical constituents of the roots of Anemone altaica]

OBJECTIVE

To investigate the chemical constituents of the roots of Anemone altaica Fisch. ex C. A. May.

METHODS

The constituents of n-BuOH-soluble portion were isolated and purified by means of chromatography. Compounds were identified by their physical characteristics and spectral features.

RESULTS

Six compounds were isolated and identified as cimigenol-3-O-beta-D-xylopyranoside (1), cimigenol-3-O-beta-D-xylopyranol (1 -->3)-beta-D-xylopyranoside (2), isolariciresinol-9-O-beta-D-glucopyranoside (3), adenosine (4), uridine (5) and methyl-beta-D-glucopyranoside (6).

CONCLUSION

All compounds are isolated from this genus for the first time.

Covalently bonded DNA aptamer chiral stationary phase for the chromatographic resolution of adenosine

In this work, a target-specific aptamer chiral stationary phase (CSP) based on the oligonucleotidic selector binding to silica particles through a covalent linkage was developed. An anti-D-adenosine aptamer was coupled, using an in-situ method, by way of an amide bond to macroporous carboxylic acid based silica. Frontal chromatography analysis was performed to evaluate the column properties, i.e., determination of the stationary phase binding capacity and the dissociation constant of the target-immobilized aptamer complex. It was found that such covalent immobilization was able to maintain the aptamer binding properties at a convenient level for an efficient enantioseparation. Subsequently, the separation of adenosine enantiomers was investigated under different operating conditions, including changes in the eluent's ionic strength and the proportion of organic modifiers as well as column temperatures. It was demonstrated that, under various conditions of use and storage, the present CSP was stable over time.

[Chemical study on fruiting bodies of Boletus vioaceo-fuscus]

OBJECTIVE

To investigate the chemical constituents of Boletus vioaceo-fuscus.

METHOD

The compounds were isolated with column chromatography. The structures were determined by spectroscopic techniques.

RESULT

Six compounds were isolated from the fruiting bodies of Boletus vioaceo-fiuscus. They were identified as ergosta-5, 7, 22-triene-3beta-ol (1), dihydrofuran-2, 5-dione (2), (22E, 24R)-5alpha, 6alpha-epoxyergosta-8, 22-diene-3beta, 7alpha-diol (3), (22E, 24R)-5alpha, 6alpha-epoxyergosta-8 (14), 22-diene-3beta, 7alphadiol (4), cerebroside B (5) and adenosine (6), respectively.

CONCLUSION

All the Compounds were obtained from the fruiting bodies of Boletus vioaceo-fiscus for the first time.

[Studies on chemical constituents in seeds of Cicer arietinum]

OBJECTIVE

To study the chemical constituents in seeds of Cicer arietinum, so that to find bioactive natural products.

METHOD

Dried and sprouted seeds of C. arietinum were extracted with ethanol of various concentrations respectively, then isolated and purified by silica gel, macroreticular resin D 101, Sephadex LH -20 gel column chromatography, and structures of compounds were identified by spectral analysis.

RESULT

Nine compounds have been isolated and identified: 3-hydroxy-olean-12-ene (1), biochanin A-7-O-beta-D-glucoside (2), cerebroside (3), 1-ethyl-alpha-L-galactoside (4), uridine (5), adenosine (6), trytophan (7), biochanin A (8), fomononetin (9).

CONCLUSION

Compounds 1, 3, 4, 6, 7 were isolated from genus Cicer for the first time.

[Chemical study of nucleosides on Cordyceps militaris]

OBJECTIVE

To investigate the nucleosides of Cordyceps militaris.

METHODS

The primary extract technique of nucleosides from Cordyceps militaris was founded, the nucleosides were isolated by chromatography.

RESULTS

Four compounds were isolated from the mycelium of Cordyceps militaris. They were identified as uridine (1), adenosine (2), guanosine (3) and p-tyrosine (4), respectively.

CONCLUSION

Compounds 1, 2 and 3 are the main nucleosides in Cordyceps militaris.

[Non-saponins from Solanum nigrum L]

OBJECTIVE

Chemical constituents of the non-saponins from Solonum nigrum L. were studied.

METHODS

The separation was performed on the silic gel CC, Sephadex-LH20 CC as well as preparative HPLC. The constituents were isolated and identified by spectral methods.

RESULTS

Five compounds isolated from 60% ethanol extract werre identified as 6-methoy-hydroxycoumarin (I), syringaresinol-4-O-beta-D-glucopyranoside (II), pinoresinol-4-O-beta-D-glucopyranoside (III), 3, 4-dihydroxhbenzoic acid (IV), p-hydroxybenzoic acid (V), 3-methoxy-4-hydroxyienzoic acid (VI), adenosine (VII).

CONCLUSION

II, III, and VII were isolated from this genus for the first time.

Neuroprotective principles from Gastrodia elata

Serum deprivation-induced neuronal-like PC12 cell apoptosis was used as an ischemic/hypoxic model to screen neuroprotective compounds from the rhizomes of Gastrodia elata, a traditional Chinese medicine. Two active compounds, bis(4-hydroxybenzyl)sulfide (1) and N6-(4-hydroxybenzyl)adenine riboside (2), together with 15 known compounds were obtained from the active fraction. Compound 2 was further elucidated by chemical synthesis. Compounds 1 and 2 potently prevented PC12 cell apoptosis in concentration-dependent manners with EC50 values of 7.20 microM and 3.7 x 10-8 M, respectively, and IC50 values of 42.90 microM (Ki 24.10 microM) and 4.660 microM (Ki 2.620 microM), respectively, in an adenosine A2A receptor binding assay.

The protective effects of phenolic constituents fromGastrodia elata on the cytotoxicity induced by KCl and glutamate

Seven phenolic compounds (1-7) were isolated from the tubers of Gastrodia elata. Their structures were elucidated on the basis of MS and NMR spectral data. p-Ethoxymethyl phenyl-O-beta-D-glucoside (1) was proved to be a new compound, with N-(p-hydroxybenzyl)-adenosine (7) isolated from this plant for the first time. In this study, the protective effects of the six constituents (1-6) on PC12 cells against the cytotoxicity induced by KCl and glutamate were also investigated. The viability of the PC12 cells was significantly enhanced by pretreatment with the six phenolic constituents.

[Chemical constituents from tuber of Cremastra appendiculata]

OBJECTIVE

To investigate the chemical constituents from the tuber of the planted Cremastra appendiculata.

METHOD

The compounds were isolated by column chromatography over silica gel, Sephadex LH-20 and RP-HPLC, and their structures were elucidated on the basis of spectroscopic analysis.

RESULT

Eight compounds were isolated, and identified as cirrhopetalanthrin (I), 7-hydroxy-4-methoxyphenanthrene-2-O-beta-D-glucoside (II), 4-(2-hydroxyethyl)-2-methoxyphenyl-1-O-beta-D-glucopyranoside (III), tyrosol 8-O-beta-D-gluco-pyranoside (IV), vanilloloside (V), p-hydroxybenzaldehyde (VI), sucrose (VII), adenosine (VIII).

CONCLUSION

These compounds are isolated from this plant for the first time. All compounds were evaluated against human colon cancer (HCT-8), human hepatoma (Bel7402), human stomach cancer(BGC-823), human lung adenocarcinoma (A549), human breast cancer (MCF-7), and human ovarian cancer (A2780) cell lines, and cirrhopetalanthrin (I) showed non-selective moderate cytotoxicity with IC50 values of 8.4-13.3 micromol x L(-1), and other compounds were inactive.

On-line hyphenation of quantum cascade laser and capillary electrophoresis

We report the first successful hyphenation of a Fabry Pérot quantum cascade (QC) laser to a capillary electrophoresis system. This involved use of a dedicated IR-transparent flow cell, made of CaF2, constructed by means of SU-8 based lithography and low temperature wafer bonding techniques. Adenosine, guanosine, xanthosine and adenosine-5'-monophosphate were separated in a borate-containing separation electrolyte (10 mM, pH 9.3). Functional group (carbohydrate) detection was accomplished by use of the 1080 cm(-1) emission line of the available QC-laser. The assessable optical path length could be increased, from the normally available 10-15 microm in CE-FTIR analyses, to 60 microm using this powerful mid-infrared laser and aqueous solutions.

Streptavidin chiral stationary phase for the separation of adenosine enantiomers

In this paper, a microbore column packed with streptavidin particles was used, at various temperatures (0-24 degrees C), to separate the adenosine enantiomers by HPLC. Using an aqueous mobile phase, the apparent enantioseparation was high for a small molecule, varying from 11.5 at 0 degrees C to 6.2 at 24 degrees C. From the experiments carried out with a streptavidin-biotin complex stationary phase, it was demonstrated that the blockage of the biotin sites of the immobilized streptavidin was responsible for a strong decrease in the enantioselectivity via a direct and/or an indirect effect. From the analysis of the concentration dependencies of the solute retention factor, it was also shown that a reduction of the D-adenosine specific binding sites occurred at the lowest temperature. The thermodynamic parameters determined from the van't Hoff plots indicated that the D-adenosine binding to the streptavidin specific sites was enthalpically driven.

[Study on the chemical constituents of Selaginella tamariscina (Beauv.) Spring]

AIM

To study the chemical constituents of Selaginella tamariscina (Beauv.) Spring.

METHODS

Various chromatographic techniques were used to separate and purify the chemical constituents. Their physico-chemical properties and spectral data were used to elucidate the structures.

RESULTS

Four compounds were isolated from the n-BuOH fraction of the water-extracts. Their structures were identified as 1-hydroxy-2-[2-hydroxy-3-methoxy-5-(1-hydroxyethyl)-phenyl]-3-(4-hydroxy-3,5-dimethoxy)-propane-1-O-beta-D-glucopyranoside (tamariscinoside B, I), adenosine (II), guanosine (III), arbutin (IV).

CONCLUSION

Tamariscinoside B (I) is a new compound, while the others were isolated from Selaginella for the first time.

Induction of 3'-O-beta-D-ribofuranosyl adenosine during compatible, but not during incompatible, interactions of Arabidopsis thaliana or Lycopersicon esculentum with Pseudomonas syringae pathovar tomato

All hitherto identified aromatic compounds accumulating in leaves of Arabidopsis thaliana (L.) Heynh. upon infection with virulent or avirulent strains of Pseudomonas syringae pathovar tomato ( Pst) were indolic metabolites. We now report the strong accumulation of a novel type of natural product, 3'-O-beta-D-ribofuranosyl adenosine (3'RA), exclusively during compatible interactions. In contrast to the various indolic metabolites, 3'RA was undetectable in incompatible interactions of A. thaliana leaves with an avirulent Pst strain, as well as in uninfected control leaves. A similar, strong induction of 3'RA was observed in compatible but, again, not in incompatible interactions of Pst with its natural host, Lycopersicon esculentum. The strength of the effect and its confinement to compatible interactions suggests that it may be applicable as a diagnostic tool.