5-alk(en)ylresorcinols as the major active components in wheat bran inhibit human colon cancer cell growth

We and others have found that wheat bran oil is the active constituent in wheat bran for colon cancer prevention. However, the active components in wheat bran oil are still unknown. Using human colon cancer cells (HCT-116 and HT-29) as the guiding assays, we further purified the active components from wheat bran using column chromatography. In this study, we identified that a fraction containing 5-n-alk(en)ylresorcinols had the strongest inhibitory effect on the proliferation of human HCT-116 and HT-29 colon cancer cells. Further purification led to the identification of 14 5-alk(en)ylresorcinols. Among them, 7, (10'Z,13'Z,16'Z)-5-(nonadeca-10',13',16'-trienyl)resorcinol, is a novel compound and 5, 6, 9, 10, and 13 were purified as individual compounds for the first time. The identification and structural elucidation of these compounds were based on 1D and 2D NMR and tandem mass spectral analyses. All these compounds (1-14) except 10 were evaluated for growth inhibition of human colon cancer cell lines (HCT-116 and HT-29). Our results indicate that increasing the length of the side chain will diminish the inhibitory activity, and the existence of a double bond and a carbonyl group will strengthen such an activity.     

三七环二肽成分

从三七(Panax notoginseng)的根中分离得到14个环二肽成分,通过波谱解析其结构分别鉴定为环-(亮氨酸-苏氨酸)(1)、环-(亮氨酸-异亮氨酸)(2)、环-(亮氨酸-缬氨酸)(3)、环-(异亮氨酸-缬氨酸)(4)、环-(亮氨酸-丝氨酸)(5)、环-(亮氨酸-酪氨酸)(6)、环-(缬氨酸-脯氨酸)(7)、环-(丙氨酸-脯氨酸)(8)、环-(苯丙氨酸-酪氨酸)(9)、环-(苯丙氨酸-丙氨酸)(10)、环-(苯丙氨酸-缬氨酸)(11)、环-(亮氨酸-丙氨酸)(12)、环-(异亮氨酸-丙氨酸)(13)、环-(缬氨酸-丙氨酸)(14)。其中化合物1为新化合物,化合物4～10为新天然化合物,化合物2～3、11～14为已知化合物;化合物2和11、3和4、12和13分别为一对混合物,比例分别为2：1、1：1和2：1。     

A C13-norisoprenoid gentiobioside from quince fruit.

The beta-D-gentiobioside [beta-D-glucopyranosyl(1----6)-beta-D-glucopyranoside] of 3-hydroxy-beta-ionol has been isolated and characterized in quince (Cydonia oblonga) fruit through spectral and chemical studies. Model experiments carried out with this new natural compound revealed its important role as precursor of a number of C13-norisoprenoid flavour compounds of quince essential oil.     

In vivo labeling with stable isotopes as a tool for the identification of unidentified peaks in the metabolome analysis of Corynebacterium glutamicum by GC/MS

Of the hyphenated techniques used for metabolic profiling of cell and tissue extracts, GC/MS is in some ways advantageous as it allows the simultaneous fingerprinting of chemically very different metabolites, and the electron impact mass spectra recorded in many cases lead to unambiguous identification of the compounds. However, prior to chromatography, the hydrophilic substances of the cell extracts have to be converted to vaporizable derivatives, the mass spectra of which often are not known or not listed in the available spectral libraries, even if they are derived from simple biochemicals. Thus, numerous chromatographic peaks remain as yet unidentified. Attempts to identify these peaks afford the acquisition of more data on these compounds. The value of in vivo labeling of metabolites with (13)C and (15)N for this purpose is described.     

New sesquiterpene lactones from Inula oculus-christi L.

Investigation of the aerial parts of Inula oculus-christi L. led to the identification of four new sesquiterpene lactones: an eudesmanolide (4α,15α-epoxypulchellin E) and three guaianolides (2α-acetoxy-4α,9β-dihydroxy-1β-guaia-11(13),10(14)-dien-12,8α-olide, 9β,10β-epoxygaillardin, 9α,10α-epoxy-2-epi-gaillardin), in addition to the known gaillardin, pulchellin E, pulchellin C and 3-O-palmitates of 16β-hydroxylupeol, 16β-hydroxy-β-amyrin, and faradiol. The structures of all compounds have been elucidated on the basis of their spectral data.     

New Natural Products from Asphodelus albus MILL. Essential Oil

A detailed chemical analysis of the essential oil of Asphodelus albus roots performed in this work, in combination with a chemical synthesis approach – the synthesis of selected compounds and their detailed spectral analysis – has led to the identification of a series of new natural products, the esters of furan-3-ylmethanol: furan-3-ylmethyl 2-methylpropanoate, furan-3-ylmethyl butanoate, furan-3-ylmethyl 2-methylbutanoate, furan-3-ylmethyl 3-methylbutanoate, furan-3-ylmethyl pentanoate, furan-3-ylmethyl 4-methylpentanoate, and furan-3-ylmethyl hexanoate.     

Sulfonamides containing curcumin scaffold: Synthesis,characterization, carbonic anhydrase inhibition and molecular docking studies

Curcumin is a multi-functional pharmacologically safe natural agent with proven cytoprotective effects to healthy human cells. In this study, a new series of sulfonamides with curcumin scaffold were synthesized, characterized and investigated for their carbonic anhydrase isoenzyme I (human) and II (bovine) isoforms. The structures of newly synthesized compounds were described by IR, ¹H NMR and ¹³C NMR spectral data. Compound 14 showed the K_i value of 0.99 µM with highest inhibitory activity among all other synthesized compounds against hCA-I enzyme. Similarly enzyme kinetic studies of compound 14, 16 and 30 against bCAII enzyme showed Ki values of 0.71, 0.67 and 0.71 µM respectively. Our biological assays results showed that most of active compounds have similar inhibitory activities compared to standard acetazolamide drug. The molecular docking predicted binding modes showed that these compounds bind with hCA-1 enzyme in similar fashion.     

Structure based virtual screening, 3D-QSAR,molecular dynamics and ADMET studies for selection of natural inhibitors against structural and non-structural targets of Chikungunya

The transmission of mosquito-borne Chikungunya virus (CHIKV) has large epidemics worldwide. Till date, there are neither anti-viral drugs nor vaccines available for the treatment of Chikungunya. Accumulated evidences suggest that some natural compounds i.e., Epigallocatechin gallate, Harringtonine, Apigenin, Chrysin, Silybin, etc. have the capability to inhibit CHIKV replication in vitro. Natural compounds are known to possess less or no side effects. Therefore, natural compound in its purified or crude extracts form could be the preeminent and safe mode of therapies for Chikungunya. Wet lab screening and identification of natural compounds against Chikungunya targets is a time consuming and expensive exercise. In the present study, we used in silico techniques like receptor-ligand docking, Molecular dynamic (MD), Three Dimensional Quantitative Structure Activity Relation (3D-QSAR) and ADME properties to screen out potential compounds. Aim of the study is to identify potential lead/s from natural sources using in silico techniques that can be developed as a drug like molecule against Chikungunya infection and replication. Three softwares were used for molecular docking studies. Potential ligands selected by docking studies were subsequently subjected 3D-QSAR studies to predict biological activity. Based on docking scores and pIC₅₀ value, potential anti-Chikungunya compounds were identified. Best docked receptor-ligands were also subjected to MD for more accurate estimation. Lipinski’s rule and ADME studies of the identified compounds were also studied to assess their drug likeness properties. Results of in silico findings, led to identification of few best fit compounds of natural origin against targets of Chikungunya virus which may lead to discovery of new drugs for Chikungunya.

Communicated by Ramaswamy H. Sarma     

Cytotoxicity and immunomodulating characteristics of labdane diterpenes from Marrubium cylleneum and Marrubium velutinum

From the aerial parts of Marrubium cylleneum, one labdane nor-diterpene has been isolated together with two labdane diterpenes, hitherto not known as natural products. The structures of the isolated compounds were established by means of NMR [(1)H-(1)H-COSY, (1)H-(13)C-HSQC, HMQC-TOCSY, HMBC, NOESY] and MS spectral analyses. Several diterpenoids from M. cylleneum and M. velutinum were tested for their cytotoxic effect against various cancer cell lines and their immunomodulating potential in human peripheral blood mononuclear cells in standard in vitro assays. Our results show a differential cytotoxicity of some compounds as well as their ability to improve selected lymphocyte functions.     

HPLC Retention time prediction for metabolome analysi

Liquid Chromatography Time-of-Flight Mass Spectrometry (LC-TOF-MS) is widely used for profiling metabolite compounds. LC-TOF-MS is a chemical analysis technique that combines the physical separation capabilities of high-pressure liquid chromatography (HPLC) with the mass analysis capabilities of Time-of-Flight Mass Spectrometry (TOF-MS) which utilizes the difference in the flight time of ions due to difference in the mass-to-charge ratio. Since metabolite compounds have various chemical characteristics, their precise identification is a crucial problem of metabolomics research. Contemporaneously analyzed reference standards are commonly required for mass spectral matching and retention time matching, but there are far fewer reference standards than there are compounds in the organism. We therefore developed a retention time prediction method for HPLC to improve the accuracy of identification of metabolite compounds. This method uses a combination of Support Vector Regression and Multiple Linear Regression adaptively to the measured retention time. We achieved a strong correlation (correlation coefficient = 0.974) between measured and predicted retention times for our experimental data. We also demonstrated a successful identification of an E. coli metabolite compound that cannot be identified by precise mass alone.     

Use of mathematically enhanced spectral analysis and spectral contrast techniques for the liquid chromatographic and capillary electrophoretic detection and identification of pharmaceutical compounds

The use of mathematically enhanced ultraviolet/visible (UV/VIS) absorbance spectral analysis and spectral contrast software techniques in high performance liquid chromatography (HPLC) and micellar electrokinetic capillary electrophoresis (MECC) as an aid for the determination of peak homogeneity, identification, and tracking during method development was investigated. Various structurally similar pharmaceutical compounds, and compounds present as either cis/trans isomers, diastereomers, or enantiomers were used as test compounds to probe the limits of this technique. Two tricyclic antidepressants, nortriptyline and imipramine, were employed to study the effects of HPLC mobile phase composition and pH on the ability to identify and track peaks during method development. It was found that method changes altered the spectral matches used for identification, but not enough to cause incorrect peak identification. It was also shown using HPLC that the cis/trans isomers of doxepin and the diastereomers ephedrine and pseudoephedrine could be distinguished. The mathematically enhanced spectral analysis and spectral contrast software techniques were also employed with MECC. Peaks tracking during method development as pH and the concentration of surfactant changes is shown for a separation of various penicillin type antibiotics. It was shown that during chiral MECC (CMECC) analyses ephedrine/pseudoephedrine diastereomers as well as ephedrine enantiomers could be distinguished. The determination of enantiomers is possible in CMECC since enantiomers are eluted as diastereomeric complexes, as opposed to HPLC where they are eluted in their native state. © 1996 Wiley-Liss, Inc.     

Activity of lupane triterpenoids from Maytenus species as inhibitors of nitric oxide and prostaglandin E2

In the present study, we report that three new lupane triterpenes (1-3), in addition to 16 known ones (4-19), were isolated from the root bark of Maytenus cuzcoina and the leaves of Maytenus chiapensis. Their structures were elucidated by spectral analysis, including homonuclear and heteronuclear correlation NMR experiments (COSY, ROESY, HSQC, and HMBC). The natural compounds and derivatives 6a, 6b, 9a, and 9b have been tested for potential anti-inflammatory activity, and several compounds including 3-epicalenduladiol (2), 11alpha-hydroxy-glochidone (3), rigidenol (6), acetoxy-rigidenol (6a), 11alpha-acetoxy-30-chloro-3-oxo-lup-20(29)-ene (6b), betulin (9), 28-acetoxy-betulin (9a), epibetulin (12), epibetulinic acid (13), and betulonic acid (16) exhibited potent inhibitory effects on NO and prostaglandin E(2) production in mouse macrophages (RAW 264.7) stimulated with bacterial endotoxin. The structure-activity relationship is discussed in detail.     

Synthesis and study of cyclic and linear analogs of neurotensin

New cyclic analogues of neurotensin (NT): [cyclo (13----8), Gly8]NT-(8-13), [cyclo (13----7), Gly7]NT-(7-13), [cyclo (13----5 epsilon), Lys5]NT-(5-13), [cyclo (13----4 epsilon), Lys4]NT-(4-13), and their linear precursors have been synthesized. The latter (protected linear compounds) were prepared by solid-phase peptide synthesis, and cyclization was attained by using diphenylphosphoryl azide. Cyclization of C-terminal hexa- and octapeptide fragments of NT was found to lead to cycloanalogues possessing high depressor activity. As judged by CD spectral data in aqueous solution, the cyclohexapeptide analogue has a relatively rigid conformation different from its linear counter-part and the NT-(9-13) fragment, whereas NT, its cyclohepta- and cyclononapeptides have random structure.     

Three new steroids from the roots of Serratula wolffii

Investigation of the methanol extract of the roots of Serratula wolffii resulted in an ecdysone-related compound, 2beta,3beta,20R,22R,25-pentahydroxy-5beta-cholest-6,8(14)-dien (1), a new ecdysteroid, 24-methylene-shidasterone (2), the known compound stachysterone B (3) and its 14,15-alpha-epoxide (4), a novel natural product. The structures of compounds 1-4 were established by spectral analysis ((1)H NMR, (13)C NMR, COSY, NOESY, HMQC, HMQC-TOCSY and HMBC).     

Two New Coumarins from Fraxinus chinensis Rexb.

The ethanol extract of the stem bark of Fraxinus chinensis Roxb. showed good inhibitory bioactivity against VEGF receptor-1 kinase （IC50：13.8 μg/mL）. In order to find new and bioactive compounds, the chemical constituents of the stem bark of F. chinensis were investigated and two new coumarins, namely 6＇-O-sinapinoyl esculin （compound 1） and 6＇-O-vanillyl esculin （compound 2）, together with eleven known compounds （compounds 3-13） were isolated. The structures of the two new compounds were identified by their physicochemical properties and spectral analysis, particularly one- and two-dimensional nuclear magnetic resonance spectral methods. The known compound, oleuropein （compound 11）, exhibited moderate activity （IC50：（8.7 ± 1.3） μmol/L） to inhibit VEGF receptor- 1 kinase.     

Isolation and characterization of naturally occurring cyanogenic compounds

The literature dealing with the detection, isolation, purification and characterization of cyanogenic glycosides has been integrated with spectral and chemical data as well as other techniques from our laboratory to establish a method for the positive identification of glycosides of this type. The compounds are arranged into biosynthetically related groups (those derived from l-phenylalanine; l-tyrosine; l-leucine, l-valine; l-isoleucine; those with cyclopentene rings and pseudocyanogenic glycosides) and features of each of the above procedures are critically reviewed and spectral data for each group presented (IR, MS, UV and NMR). The NMR spectra of TMS ethers of cyanogenic glycosides have proven especially useful in chemical structure determination. This information is sufficient to permit identification of any of the 26 known glycosides as well as certain uncharacterized ones.     

Strategies for dereplication of natural compounds using high-resolution tandem mass spectrometry

Complete structural elucidation of natural products is commonly performed by nuclear magnetic resonance spectroscopy (NMR), but annotating compounds to most likely structures using high-resolution tandem mass spectrometry is a faster and feasible first step. The CASMI contest 2016 (Critical Assessment of Small Molecule Identification) provided spectra of eighteen compounds for the best manual structure identification in the natural products category. High resolution precursor and tandem mass spectra (MS/MS) were available to characterize the compounds. We used the Seven Golden Rules, Sirius2 and MS-FINDER software for determination of molecular formulas, and then we queried the formulas in different natural product databases including DNP, UNPD, ChemSpider and REAXYS to obtain molecular structures. We used different in-silico fragmentation tools including CFM-ID, CSI:FingerID and MS-FINDER to rank these compounds. Additional neutral losses and product ion peaks were manually investigated. This manual and time consuming approach allowed for the correct dereplication of thirteen of the eighteen natural products.     

Decision tree supported substructure prediction of metabolites from GC-MS profiles

Gas chromatography coupled to mass spectrometry (GC-MS) is one of the most widespread routine technologies applied to the large scale screening and discovery of novel metabolic biomarkers. However, currently the majority of mass spectral tags (MSTs) remains unidentified due to the lack of authenticated pure reference substances required for compound identification by GC-MS. Here, we accessed the information on reference compounds stored in the Golm Metabolome Database (GMD) to apply supervised machine learning approaches to the classification and identification of unidentified MSTs without relying on library searches. Non-annotated MSTs with mass spectral and retention index (RI) information together with data of already identified metabolites and reference substances have been archived in the GMD. Structural feature extraction was applied to sub-divide the metabolite space contained in the GMD and to define the prediction target classes. Decision tree (DT)-based prediction of the most frequent substructures based on mass spectral features and RI information is demonstrated to result in highly sensitive and specific detections of sub-structures contained in the compounds. The underlying set of DTs can be inspected by the user and are made available for batch processing via SOAP (Simple Object Access Protocol)-based web services. The GMD mass spectral library with the integrated DTs is freely accessible for non-commercial use at . All matching and structure search functionalities are available as SOAP-based web services. A XML + HTTP interface, which follows Representational State Transfer (REST) principles, facilitates read-only access to data base entities.     

Synthesis of N- and S-bis-protected lactosyl isothiobiurets

Several N,S-bis(hepta-O-acetyllactosyl)-1-aryl-2-isothiobiuret compounds have been synthesised for the first time by the reaction of S-(hepta-O-acetyl-beta-lactosyl)-1-arylisothiocarbamides and hepta-O-acetyl-beta-lactosyl isocyanate. The identities of these newly synthesised compounds were established on the basis of elemental analysis and IR, (1)H NMR, (13)C NMR and mass spectral studies.     

Synthesis and antimicrobial studies of novel 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-one 4'-phenylthiosemicarbazones

New series of 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-one 4'-phenylthiosemicarbazones (compounds 9-16) was obtained from the corresponding 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones. The synthesized compounds have been characterized by their elemental, analytical, and spectral studies. Besides, these reported compounds were screened for their antibacterial and antifungal activities against a spectrum of microbial organisms. These studies proved that against bacteria, compounds 10 and 11 against Bacillus subtilis, compound 13 against Salmonella typhi, show maximum inhibition potency at low concentration (6.25 μg/mL), whereas against fungal, compounds 11, 13, and 16 against Candida albicans and compounds 12 and 13 against Cryptococcus neoformans, showed beneficial antifungal activity at minimum concentration (6.25 μg/mL).