Structure Elucidation of Triterpenoid Saponins Found in an Immunoadjuvant Preparation of Quillaja brasiliensis Using Mass Spectrometry and 1H and 13C NMR Spectroscopy.

An immunoadjuvant preparation (named Fraction B) was obtained from the aqueous extract of Quillaja brasiliensis leaves, and further fractionated by consecutive separations with silica flash MPLC and reverse phase HPLC. Two compounds were isolated, and their structures elucidated using a combination of NMR spectroscopy and mass spectrometry. One of these compounds is a previously undescribed triterpene saponin (Qb1), which is an isomer of QS-21, the unique adjuvant saponin employed in human vaccines. The other compound is a triterpene saponin previously isolated from Quillaja saponaria bark, known as S13. The structure of Qb1 consists of a quillaic acid residue substituted with a ß-d-Galp-(1→2)-[ß-d-Xylp-(1→3)]-ß-d-GlcpA trisaccharide at C3, and a ß-d-Xylp-(1→4)-α-l-Rhap-(1→2)-[α-l-Arap-(1→3)]-ß-d-Fucp moiety at C28. The oligosaccharide at C28 was further substituted at O4 of the fucosyl residue with an acyl group capped with a ß-d-Xylp residue.

Chemical characterisation and in vitro anthelmintic activity of phenolic-rich extracts from the leaves and branches of Maytenus ilicifolia, a native plant from South America.

Free (epi) catechin, quercetin, (epi) gallocatechin, flavonol glycosides and condensed tannins were identified according to their molecular mass, characteristic product ions and retention times in extracts obtained from leaves and branches of Maytenus ilicifolia (Congorosa) by mass spectrometry. The in vitro anthelmintic activity against cattle gastrointestinal nematodes of Congorosa extract was determined using the Egg Hatch Inhibition Assay. Additionally, commercial quercetin, gallocatechin and epicatechin were evaluated. Although total phenolics, total tannins and condensed tannins contents were lower in branches extract than in leaves extract, the EC50 were 0.065 mg/mL and 0.890 mg/mL for branches and leaves extract, respectively. Moreover, the use of polyvinylpyrrolidone as a blocking agent of tannins, did not change significantly the EC50 for branches extract, but significantly changed for leaves extract. Quercetin and gallocatechin EC50 values were in the range 0.03-0.05 mg/mL and epicatechin showed 100% inhibition of the egg hatching process at 0.004 mg/mL.

Characterization of Melanoidins and Color Development in Dulce de Leche, a Confectionary Dairy Product With High Sucrose Content: Evaluation of pH Effect, an Essential Manufacturing Process Parameter.

The effect on color of the initial pH employed in dulce de leche (DL) production was evaluated through physicochemical and spectroscopical characterization of the melanoidins formed in the process. Melanoidins originated at pH values of 6.5, 7.0, and 7.5, and they were released by the enzymatic hydrolysis of the protein backbone and purified by gel filtration. They showed a significant degree of polydispersity, in general, with molecular weights (MWs) below 1,800 Da. DL produced at a higher pH released melanoidins with higher average MW after the enzymatic hydrolysis. They also presented darker colors (dE*ab, C*), more closely resembling those typical of the commercial product. Analysis of the fractions isolated by gel filtration using HPLC-DAD and multinuclear NMR showed an heterogeneous and complex composition. Even though structurally related, the 1H NMR spectra of melanoidins showed a higher degree of aromaticity at higher pH values. In conclusion, the pH employed in DL production affects the amount and structure of the colored products originated by MR reactions, and thus the color of the final product.

Structural characterisation of new immunoadjuvant saponins from leaves and the first study of saponins from the bark of Quillaja brasiliensis by liquid chromatography electrospray ionisation ion trap mass spectrometry.

INTRODUCTION: Quillaja brasiliensis (St. A. -Hil. & Tul) Mart (Quillajaceae) is a species native to South America, which is rich in saponins. Saponins are used in different industries, so there is a constant demand for this type of compound. Based on the wide range of applications for the saponins found in this species, notably as immunoadjuvants, we conducted a comprehensive study of this tree and its saponins. OBJECTIVE: The purpose of this work is to complete the characterisation of the immunoadjuvant saponin fraction from Q. brasiliensis leaves and further study the saponin fraction obtained from Q. brasiliensis bark. METHODOLOGY: Saponin fractions were studied using mass spectrometry in combination with classical methods of monosaccharide and methylation analysis. We performed direct infusion and liquid chromatography/electrospray ionisation ion trap multiple-stage mass spectrometry (DI-ESI-IT-MSn and LC-ESI-IT-MS2 ). RESULTS: Seventy-five saponins, 21 from leaves and 54 from bark, were tentatively identified according to their molecular mass, fragmentation pattern and chromatographic behaviour. This work represents the first investigation of saponins from the bark of Q. brasiliensis and some of them presented new structural motifs not previously reported in the genus Quillaja. CONCLUSION: The efficiency and selectivity of the data dependent LC-MS2 method allowed the rapid profiling of saponins from Q. brasiliensis. The results of the monosaccharide and methylation analysis performed in saponins from Q. brasiliensis fractions and Q. saponaria Molina (Quillajaceae) fraction gives further support to the structures proposed according to the mass spectral data, validating the strategy used in the present work.

Saponins from Quillaja saponaria and Quillaja brasiliensis: Particular Chemical Characteristics and Biological Activities.

Quillaja saponaria Molina represents the main source of saponins for industrial applications. Q. saponaria triterpenoids have been studied for more than four decades and their relevance is due to their biological activities, especially as a vaccine adjuvant and immunostimulant, which have led to important research in the field of vaccine development. These saponins, alone or incorporated into immunostimulating complexes (ISCOMs), are able to modulate immunity by increasing antigen uptake, stimulating cytotoxic T lymphocyte production (Th1) and cytokines (Th2) in response to different antigens. Furthermore, antiviral, antifungal, antibacterial, antiparasitic, and antitumor activities are also reported as important biological properties of Quillaja triterpenoids. Recently, other saponins from Q. brasiliensis (A. St.-Hill. & Tul.) Mart. were successfully tested and showed similar chemical and biological properties to those of Q. saponaria barks. The aim of this manuscript is to summarize the current advances in phytochemical and pharmacological knowledge of saponins from Quillaja plants, including the particular chemical characteristics of these triterpenoids. The potential applications of Quillaja saponins to stimulate further drug discovery research will be provided.

Xanthane sesquiterpenoids from the roots and flowers of Xanthium cavanillesii.

The sesquiterpene lactones xanthanodiene, 4-epi-xanthanol, 4-epi-isoxanthanol, and 4-epi-xanthinin, as well as the xanthanolide derivative 4-oxo-bedfordia acid were isolated from the chloroform extracts of roots and flowers of Xanthium cavanillesii Schouw. The identities of these compounds were corroborated through comparison of their spectroscopic data, including IR, MS, and (1)H and (13)C NMR assignments, with literature reports. In addition, the structural characterization of 4-oxo-bedfordia acid was revisited and a comprehensive spectroscopic study of the compound is presented. This is to our knowledge the first phytochemical investigation of the roots of X. cavanillesii, and of flowers in the whole Xanthium genus.

Prospección química y microbiológica del bosque de galería del Río Uruguay / Chemical and microbiological prospecting woodland along the Uruguay River / Prospecção química e microbiológica do bosque de galeria do Rio Uruguai

La bioprospección es la búsqueda de información a partir de especies biológicas para su uso posterior en procesos de producción en diversos sectores. Ejemplos de esa información es la contenida en el material genético de todos los seres vivos, en los compuestos químicos que producen, en sus interacciones o en el conocimiento de las personas que de una manera u otra han estudiado a esos seres vivos. En este trabajo se presentan los resultados de la prospección botánica, química y microbiológica del bosque de galería del río Uruguay en la zona del rio Queguay, ecosistema con gran biodiversidad (comprende unas 200 especies) y de características poco comunes en el país dado su carácter subtropical. Se estudiaron 75 extractos provenientes de 31 especies pertenecientes a quince familias cubriendo de esa forma una gran biodiversidad.

Bioprospecting is the search for information from biological species for later use in production processes in various sectors. Examples of this information is contained in the genetic material of all living beings in the chemicals they produce, in their interactions or the knowledge of people who in one way or another, have studied these living beings. This paper presents the results of botanical, chemical and microbiological study of the gallery forest of the Uruguay River in the area of the Queguay river. This ecosystem presents great biodiversity (comprising about 200 species) and unusual features in the country given its subtropical character. We studied 75 extracts from 31 species belonging to fifteen families covering therefore a large biodiversity.

A bioprospecção é a bisca de informações a partir de espécies biológicas para seu uso posterior em processos de produção em diversos setores. Exemplos dessa informação está contida no material genético de todos os seres vivos, nas substâncias químicas que produzem, nas suas interações ou n o conhecimento das pessoas que, de uma maneira ou de outra, estudam os seres vivos. Neste trabalho é apresentado os resultados da prospecção botânica, química e microbiológica do bosque de galeria do Rio Uruguai na zona do Rio Queguay, ecosistema com grande biodiversidade, com cerca de duzentas espécies, e de características pouco comum no país dado seu caráter subtropical. Foram estudados 75 extratos provenientes de 31 espécies pertencentes a quinze famílias, cobrindo, assim, uma grande biodiversidade.

A new bioactive xanthanolide from Xanthium cavanillesii.

Development of new antimicrobial compounds against different microorganisms is becoming critically important, as infectious diseases are still one of the leading causes of death in the world. The pharmaceutical industry is searching for new lead compounds with novel chemical structures to overcome the increasing resistance to known antibiotics. Plants can be a useful source of these lead compounds. Xanthium cavanillesii Schouw, Asteraceae, grows wild in Uruguay and its infusion is used in traditional medicine as a skin antiseptic. We have previously reported studies on the antimicrobial activity of several extracts of X. cavanillesii against different microorganisms. In this work, we present the isolation and structural elucidation by spectroscopical methods of a sesquiterpene lactone with a new xanthanolide derived skeleton.

Initial antimicrobial activity studies of plants of the riverside forests of the southern Uruguay River / Estudos antimicrobianos preliminares de plantas da floresta ribeirinha do sul do rio Uruguai

Development of new antimicrobial compounds against different microorganisms is becoming critically important, as infectious diseases are still one of the leading causes of death in the world. Plants can be a useful source of these lead compounds. In this study, 66 extracts of 25 plants of the riverside forest of southern Uruguay River were studied for antimicrobial activity against Staphylococcus aureus, Listeria inocua, Escherichia coli, Pseudomonas aeruginosa, Mycobacterium tuberculosis, Aspergillus niger and Candida albicans. Fifty-three of these extracts showed some kind of antimicrobial activity. Six of these (Eugenia mansoni, Eugenia repanda, Myrcianthes cisplatensis, Paullinia ellegans, Petunia sp and Ruprechtia laxiflora) presented activity against Mycobacterium tuberculosis with MIC values as low as 50 μg/mL.

As doenças infecciosas ainda são uma das principais causas de morte no mundo, sendo de significativa importância o desenvolvimento de novos compostos antimicrobianos contra diferentes microrganismos. As plantas podem ser uma boa fonte para direcionar a busca destes compostos. Neste estudo, 66 extratos de 25 plantas da floresta ribeirinha do sul do Rio Uruguai foram estudados para a atividade antimicrobiana contra o Staphylococcus aureus, Listeria inocua, Escherichia coli, Pseudomonas aeruginosa, Mycobacterium tuberculosis, Aspergillus niger e Candida albicans. Cinqüenta e três destes extratos apresentaram algum tipo de atividade antimicrobiana. Seis (Eugenia mansoni, Eugenia repanda, Myrcianthes cisplatensis, Paullinia ellegans, Petunia sp e Ruprechtia laxiflora) apresentaram atividade contra o Mycobacterium tuberculosis com CIM de 50 μg/mL.

Prospección química del bosque de galería del río Uruguay / Triagem fitoquímica de plantas nativas do rio Uruguai / Phytochemical screening of the native forest of Uruguay River

Prospecção da biodiversidade é a exploração de um ecossistema para se obter informações sobre possíveis utilizações inovadoras em diferentes processos de produção humanos. Exemplos do tipo de informação pretendida são os dados científicos contidos no material genético dos organismos vivos, os compostos químicos produzidos por eles e suas interações ou no conhecimento das pessoas que já interagiram com eles de várias maneiras. Uma das ferramentas de prospecção da biodiversidade é a procura por informações químicas. Esta informação está contida nos compostos produzidos por muitos seres vivos para comunicar-se, defender-se e trocar informações, e eles são conhecidos como metabólitos secundários. Neste projeto, nós propomos a prospecção botânica, química e biológica da biodiversidade da mata ciliar da Bacia do Rio Uruguay próxima ao riacho Guaviyú. Este ecossistema particular apresenta uma substancial biodiversidade de aproximadamente 200 espécies com um perfil subtropical incomum.

Biodiversity prospecting is the exploration of an ecosystem for information regarding possible innovative uses in different human production processes. Examples of the kind of information sought are the scientific data contained in the genetic material of living organisms, the chemical compounds they produce and their interactions or in the knowledge of people that have interacted with them in various ways. One of the tools of biodiversity prospecting is searching for chemical information. This information is contained in the compounds produced by many living beings to communicate, to defend themselves and exchange information, and they are known as secondary metabolites. In this project, we propose the botanical, chemical and biological biodiversity prospecting of the gallery forest of the Uruguay River Basin near the Guaviyú stream. This particular ecosystem presents a substantial biodiversity of approximately 200 species with an unusual subtropical profile.