15N-NMR spectroscopic studies and investigation of spectral data property relationships of proton pump inhibitors

In this study, the relationships between 15N-NMR and 13C-NMR chemical shifts of omeprazole, lansoprazole, ilaprazole,pantoprazole, and rabeprazole and their physicochemical and pharmacokinetic properties, namely, pKa, half-life,tmax, logP, and protein binding were investigated. This study also presents the first report of 15N-NMR spectroscopicstudies of lansoprazole, pantoprazole, and ilaprazole. It was found that 15N-NMR chemical shifts of the doubly bondedbenzimidazole nitrogen of proton pump inhibitors showed correlation with pKa2, protein binding and logP, while 15NNMR chemical shifts of the pyridine nitrogen correlate with protein binding and tmax. Sum of 15N-NMR chemical shiftsand sum of 13C-NMR chemical shifts, both, exhibit correlation with half-life, logP, and tmax. The sum of 13C chemicalshifts of the pyridine moiety exhibits correlation with pKa1, while the sum of 13C chemical shifts of the benzimidazolemoiety exhibits correlation with half-life. NMR chemical shifts may, hence, be useful as molecular descriptors in thedevelopment of Quantitative Structure/Spectral Data Property Relationship models.

Triterpene saponins in Panax japonicus and their ~(13)C-NMR spectroscopic characteristics / 中国中药杂志

Panax japonicus( PJ) is a valuable medicinal plant belonging to the genus Panax of Araliaceae,the recumbent rhizome of which is widely used in clinic therapy,healthcare products and as cosmetic additives with functions of dissipating stasis,reducing swelling,stanching bleeding,and reinforcing deficiency,etc. PJ contains abundant levels of oleanane-and dammarane-type triterpene saponins,which are considered as the material basis for exerting pharmacodynamic action. Based on the previous researches,more than110 triterpene saponins have been reported from PJ. These triterpene saponins were summarized in this review,and could be classified into dammarenediol Ⅱ,protopanaxadiol,protopanaxatiol,ocotillol,oleanolic acid,ursolic acid and miscellaneous subtypes,according to their molecular skeletons in biosynthesis processes. Further more,the structural features of these triterpene saponins in the seven different subtypes,together with their~(13)C-NMR spectroscopic characteristics were described,hoping to provide available information for chemical diversity research of PJ.

13C NMR Analysis: Terpenoids, Steroids and Carotenoid from Diospyros soubreana (Ebenaceae)

Phytochemical investigations on bark of trunks and leaves of Diospyros soubreana (Ebenaceae) led to the isolation and characterisation of nine molecules: one monocyclic sesquiterpenoid lactone (1), five pentacyclic triterpenes (2, 3, 4, 5 and 6), two sterols (7 and 8) and one carotenoid alcohol (9), all isolated for the first time from this species. The structural elucidation of these compounds was carried out by 13C NMR spectroscopy.

Chemical composition of the leaf oil of Artabotrys jollyanus from Côte d'Ivoire

ABSTRACT One oil sample isolated from leaves of Artabotrys jollyanus Pierre, Annonaceae, from Côte d'Ivoire has been analyzed by GC(RI), GC-MS and 13C NMR. In total, thirty-seven compounds accounting for 96.9% of the relative composition have been identified. The composition of the essential oil was dominated by trans-calamenene (15.7%), α-copaene (14.8%), α-cubebene (10.4%), cadina-3,5-diene (10.3%), (E)-β-caryophyllene (6.3%) and cadina-1,4-diene (6.1%). 13C NMR spectroscopy was very useful in the identification of trans-calamenene, 7-hydroxycalamenene, cadina-3,5-diene and cadina-1,4-diene. Moreover, monitoring the evolution of the leaf essential oil composition and the yield on a 12-month period (one sample per month) was achieved. The twelve essential oil samples exhibited a chemical homogeneity but the yield varied from sample to sample (0.26-0.60%).

Multi-components compatibility theory of Chinese materia medica and IGD 13C-NMR coupling fingerprint / 中草药

Multi-components compatibility theory of Chinese materia medica (CMM) has been more and more mature and perfect, because of the efforts of many scientific and technological workers for nearly 20 years. Omics, compatibility, and fingerprint are the three key words of the multi-components compatibility theory. Namely in multi-components compatibility theory, modern "omics" and traditional "compatibility" are closely combined through "fingerprint". The modernization of CMM has developed to such a stage that the fingerprint (especially IGD 13C-NMR coupling fingerprint) method could be used to study morden CMM under the guidance of multi-components compatibility theory.

Phytochemical researches and antimicrobial activity of Clinopodium nubigenum Kunth (Kuntze) raw extracts

The essential oil of the species Clinopodium nubigenum (Kunth) Kuntze, Lamiaceae, was analyzed by GC-MS and GC-FID, taking into account the more recent literature. Among the seventy compounds identified, the majority are oxygenated monoterpenoids. The essential oil, tested for antimicrobial activity, resulted effective in vitro against Candida albicans. From the aqueous MeOH extract of the aerial parts of the plant two nonvolatile compounds, named schizonepetoside A and schizonepedoside C, have been isolated. They are rare glycosyl terpenoids, which were previously isolated from only one plant, but never found before in the genus Clinopodium.

13C NMR spectral data and molecular descriptors to predict the antioxidant activity of flavonoids / Dados espectrais de RMN 13C e descritores moleculares para prever a atividade antioxidante dos flavonóides

Tissue damage due to oxidative stress is directly linked to development of many, if not all, human morbidity factors and chronic diseases. In this context, the search for dietary natural occurring molecules with antioxidant activity, such as flavonoids, has become essential. In this study, we investigated a set of 41 flavonoids (23 flavones and 18 flavonols) analyzing their structures and biological antioxidant activity. The experimental data were submitted to a QSAR (quantitative structure-activity relationships) study. NMR 13C data were used to perform a Kohonen self-organizing map study, analyzing the weight that each carbon has in the activity. Additionally, we performed MLR (multilinear regression) using GA (genetic algorithms) and molecular descriptors to analyze the role that specific carbons and substitutions play in the activity.

Danos aos tecidos devido ao estresse oxidativo estão diretamente ligados ao desenvolvimento de muitos, senão todos, os fatores de sedentarismo e de doenças crônicas. Neste contexto, a busca de moléculas naturais, que participam da nossa dieta e que possuam atividade antioxidante, flavonóides, torna-se de grande interesse. Neste estudo, nós investigamos um conjunto de 41 flavonóides (23 flavonas e 18 flavonóis), relacionando suas estruturas e atividade antioxidante. Os dados experimentais foram submetidos à análise de QSAR (relações quantitativas estrutura-atividade). Dados de RMN 13C foram utilizados para realizar um estudo do mapa auto-organizável de Kohonen, analisando o peso que cada carbono tem na atividade. Além disso, realizamos uma MLR (regressão múltipla) usando GA (algoritmos genéticos) e descritores moleculares para avaliar a influência de carbonos e substituições na atividade.

Self-organizing maps and VolSurf approach to predict aldose reductase inhibition by flavonoid compounds

Aldose Reductase (AR) is the polyol pathway key enzyme which converts glucose to sorbitol. High glucose availability in insulin resistant tissues in diabetes leads into an accumulation of sorbitol, which has been associated with typical chronic complications of this disease, such as neuropathy, nephropathy and retinopathy. In this study, 71 flavonoids AR inhibitors were subjected to two methods of SAR to verify crucial substituents. The first method used the PCA (Principal Component Analysis) to elucidate physical and chemical characteristics in the molecules that would be essential for the activity, employing VolSurf descriptors. The rate obtained explained 53 percent of the system total variance and revealed that a hydrophobic-hydrophilic balance in the molecules is required, since very polar or nonpolar substituents decrease the activity. Artificial Neural Networks (ANNs) was also employed to determine key substituents by evaluating substitution patterns, using NMR data. This study had a high success rate (85 percent accuracy in the training set and 88 percent accuracy in the test set) and showed polihydroxilations are essential for high activity and methoxylations and glicosilations primarily at positions C7, C3' and C4' decrease the activity.

Intervalos de ittegración unificados para la caacterización estructural de pettróleos, carbones o sus fracciones por rmn ¹h y rmn 13c / Unified inegratiion intervls for the structural characterization of oil, coal or fractions there of by 1h nmr and 13c nmr / Intervalos de integração unificados para a caracterização estrutural de petróleos, carvões ou suas frações por rmn ¹h e rmn 13c

Con base en la revisión de publicaciones, hechas entre 1972 y 2006, se evidenció que hay imprecisiones en los límites de los intervalos de integración que los autores asignan a las señales en resonancia magnética nuclear (RMN) para hacer la caracterización estructural de petróleos, carbones o sus fracciones derivadas, a partir de sus espectros de hidrógeno (RMN ¹H) o de carbono (RMN 13C). En consecuencia, se determinaron límites unificados para la integración de los espectros RMN ¹H y RMN 13C de tales muestras mediante un tratamiento estadístico aplicado a los límites de los intervalos de integración ya publicados. Con esos límites unificados se elaboraron cartas de correlación en RMN útiles para la asignación de la integral en esos intervalos, y aun en otros de menor extensión definidos en función de la intersección entre asignaciones diferentes. Además se plantearon ecuaciones necesarias para establecer la integral atribuible a fragmentos más específicos en un intento por hacer una caracterización estructural más exacta a partir de los espectros RMN de petróleos, carbones o sus fracciones deriva.

Based on an analysis of publications reported between 1972 and 2006, it became clear that there are inaccuracies in the limits of the ranges of integration that the authors assigned to signals in nuclear magnetic resonance (NMR) to the structural characterization of petroleum, coals and their derived fractions, from their hydrogen (¹H NMR) and carbon (13C NMR) spectra. Consequently, consolidated limits were determined for the integration of ¹H NMR spectra and 13C NMR of these samples using a statistical treatment applied to the limits of integration intervals already published. With these unified limits, correlation NMR charts were developed that are useful for the allocation of the integral at such intervals, and at smaller intervals defined in terms of the intersection between different assignments. Also raised equations needed to establish the integral attributable to specific fragments in an attempt to make a more accurate structural characterization from NMR spectra of oil, coal or fractions derived.

Com base na revisão de publicações, feitas entre 1972 e 2006, evidenciou-se que existem imprecisões nos limites dos intervalos de integração que os autores tem atribuído aos sinais de ressonância magnética nuclear (RMN) para a caracterização estrutural do petróleo, carvão ou suas frações derivadas, com base em seus espectros de hidrogênio (RMN ¹H) e carbono (RMN 13C). Conseqüentemente, determinaram-se os limites consolidados para a integração dos espectros de RMN ¹H e RMN 13C deste tipo de amostras usando um tratamento estatístico aplicado aos limites de intervalos de integração já publicados. Com estes limites unificados foram desenvolvidos gráficos de correlação em RMN úteis para a atribuição da integral nestes intervalos e em outros menores, definidos em termos de intersecção entre atribuições diferentes. Além do mais, levantaram-se equações necessárias para estabelecer a integral atribuível a fragmentos específicos, numa tentativa de fazer uma caracterização estrutural mais exata a partir de espectros RMN de petróleo, carvão ou frações derivadas.

Modernization of Chinese materia medica processing piece / 中草药

To elaborate the opinion on the modernization of Chinese materia medica(CMM) processing piece as CMM modernization has been fast developed with some blemish and obstacle yet.Modern CMM processing piece,guided by traditional Chinese medicine(TCM) theory,is made by science and technology of nowadays and the quality control is performed by HPLC-13C-NMR quantitative fingerprints.Also,it is evaluated through modern pharmacology and by TCM evaluation theory.Modern CMM processing piece is improved from the essence of "effective extract" and "effective fraction".CMM Granula in prescription is only considered as a primitive and junior form of the modern CMM processing piece.So modern CMM processing piece,which is feasible,controllable,compatible,and practical,is the key of the modernization and internationalization of CMM.