Mabel Fragoso

• National Autonomous University of Mexico

Phytochemical study of a CH2Cl2-soluble extract from the leaves and flowers of Decachaeta perornata (Klatt) R.M.King & H.Rob., Asteraceae, led to the isolation of two sesquiterpene lactones, a guaianolide and an eudesmanolide. The structures of both compounds were established by the extensive analyses of their 1D/2D NMR and HRMS data as xerantholid...

Frequently, preparative high-performance liquid chromatography separations of complex natural product mixtures by adsorption chromatography are erratic to achieve full baseline separation. Purification of metabolites with similar or identical polarity, such as epimers, diastereoisomers, homologs in a series, and geometric or positional isomers, by...

Flavonoids, abundant polyphenols in various plant-based sources, exhibit diverse health benefits, particularly in cancer prevention and treatment, attributed to their ability to mitigate oxidative stress. Salvigenin, a naturally occurring trimethoxylated flavone from the aerial parts of Asterohyptis stellulata Epling, Lamiaceae, has gained attentio...

Structural elucidation of specialized metabolites or natural plant products, especially the stereochemical features of chiral bioactive metabolites, is the most important stage for all investigations in pharmacognosy and phytochemistry. Numerous methods have been established to solve the absolute configuration of natural products, including direct...

The HPLC–PDA profiling of an acetone-soluble extract of the leaves of Salvia circinnata Cav. (Syn. Salvia amarissima Ortega), Lamiaceae, collected at Patzcuaro, Michoacan, Mexico, indicated this population corresponds to the chemotype “amarisolide A.” The phytochemical study of the extract led to the isolation of two new diterpenoid glucosides, ama...

Operculina hamiltonii is a vine native to the north and northeast region of Brazil, where its roots are traded as a depurative and laxative remedy with the name of Brazilian jalap in traditional medicine. Procedures for the isolation, purification by recycling HPLC, and structure elucidation of three undescribed resin glycosides are presented herei...

Jatrophenediol (1), a new pseudoguaiane sesquiterpenoid, was isolated from the roots of Jatropha dioica, together with the known diterpenoids citlalitrione (2) and jatropolones A and B (3 and 4). The structure of 1 was established based on the analysis of its spectroscopic (1D/2D NMR) and spectrometric (HRESIMS) data. The cytotoxic effect of all is...

Capsicum chinense J., also known locally as habanero pepper, is a medicinal herb known for its pharmacological properties. Its properties are attributed to the capsaicinoids and polyphenols found in its fruit and polyphenols in its by-products. The anticancer potential of C. chinense by-products remains unexplored. This study aimed to evaluate the...

Brazilian jalap root, Operculina hamiltonii (G. Don) D.F. Austin & Staple, Convolvulaceae, belongs to the morning glory family and is used as a purgative or laxative medicinal plant. After hydrolysis and peracetylation of the EtOH-soluble extract, the known operculinic acids A and B and turpethic acid C, in addition to three undescribed glycosidic...

Hyptis monticola Mart. ex Benth. (Lamiaceae) is an endemic species of altitude regions of Brazil. From the leaves of this plant, two 5,6-dihydro-α-pyrones, named monticolides A and B, have been reported as cytotoxic agents against different tumor cell lines. The isolation by high-speed countercurrent chromatography in combination with recycling pre...

Dihydro-furanones are bioactive compounds isolated from various plants, marine fungi, and sponges. The present investigation describes the isolation by recycling HPLC and structural characterization by NMR of four previously undescribed 2(5H)-furanones, monticofuranolide A and pectinolides N-P, one phenylpropanoid, rosmarinic acid, and five known f...

Salvia connivens Epling, Lamiaceae, is an annual herbaceous plant used as a traditional medicine in Mexico for the treatment of diarrhea, which out can be caused by bacterial, viral, and protozoal infections, as well as toxins mainly. Mexican medicinal plants with anti-diarrheic activity represent a source of potential antiprotozoal agents. The phy...

Phytochemical investigation of the leaves and flowers from Salvia hirsuta led to the isolation of the five microphyllane-type diterpenoids (1–5), and two flavones (6–7). Hirsutolides constituted new diterpenoids containing a 5-hydroxyfuran-2(5H)-one and were isolated as an epimeric mixture at C-3 and C-15. The structures of the isolated compounds w...

Mexican morning glory, Ipomoea tricolor Cav., is native to America and widely cultivated as an ornamental plant. High performance liquid chromatography profiling coupled with off-line electrospray mass spectrometry detection was applied to identify novel acylsugar from the CHCl3-soluble resin glycoside from seeds. Dereplication of known tricolorins...

Introduction: Hyptis verticillata Jacq. (Lamiaceae) is a Mexican medicinal plant for the treatment of skin infections and illness affecting the respiratory and gastrointestinal systems. Objective: To associate the efficient resolution provided by ultra-high-performance liquid chromatography combined to the accuracy of a hybrid Fourier-transform...

Analysis of the methanol-soluble resin glycosides from the roots of Operculina macrocarpa was assessed by generating NMR profiles of five glycosidic acids obtained through saponification, acetylation, and recycling HPLC purification. Operculinic acid H (1), two novel hexasaccharides, operculinic acids I (2) and J (3), the known purgic acid A (4), a...

Cytotoxic 6-heptyl-5,6-dihydro-2H-pyran-2-ones are chemical markers of Hyptis (Lamiaceae) and are responsible for some of the therapeutic properties of species with relevance to traditional medicine. The present investigation describes the isolation of known pectinolides A–C (1–3), in addition to the new pectinolides I–M (4–8), from two Mexican col...

Nine terpenoids were isolated from the leaves and flowers of Salvia amarissima, including a new acylated diterpenoid glucoside, amarisolide F (1), a new neo-clerodane diterpenoid, amarissinin D (2), which was isolated as an acetyl derivative (2a), and four known diterpenoids. The structure of amarisolide F (1) was elucidated by NMR and MS data anal...

En el presente estudio se llevó a cabo la evaluación del potencial citotóxico de las cáscaras de dos frutas tropicales: Annona squamosa L. (saramuyo) y Chrysophyllum cainito L. (Caimito). Los extractos metanólicos fueron obtenidos mediante maceración directa para posteriormente llevar a cabo la evaluación citotóxica por el método de Sulforodamina B...

Tropical fruit peels are generally discarded as waste, yet they contain bioactive substances that could have various uses; in addition, their pharmacological potential remains unexplored. This study aims to characterize the phytochemical profile, toxicity, and pharmacological potential of methanol extracts obtained from the peels of the following t...

High performance liquid chromatography profiling with mass spectrometry detection was applicable to identify known and novel multidrug-resistance glycolipid inhibitors from the complex resin glycosides mixture of Ipomoea alba L., Convolvulaceae, seeds. Albinosides X and XI were purified by recycling liquid chromatography and their structural elucid...

The multidrug resistance (MDR) phenotype is considered as a major cause of the failure in cancer chemotherapy. The acquisition of MDR is usually mediated by the overexpression of drug efflux pumps of a P-glycoprotein. The development of compounds that mitigate the MDR phenotype by modulating the activity of these transport proteins is an important...

Brevipolides K-O (1-5), five new cytotoxic 6-(6'-cinnamoyloxy-2',5'-epoxy-1'-hydroxyheptyl)-5,6-dihydro-2H-pyran-2-ones (IC50 values against six cancer cell lines, 1.7-10 μM), were purified by recycling HPLC from Hyptis brevipes. The structures, containing a distinctive tetrahydrofuran ring, were established by comprehensive quantum mechanical calc...

Context: Echinacea (Asteraceae) is used because of its pharmacological properties. However, there are few studies that integrate phytochemical analyses with pharmacological effects. Objective: Evaluate the chemical profile and biological activity of hydroalcoholic Echinacea extracts. Materials and methods: Density, dry matter, phenols (Folin–Ciocal...

Multidrug resistance is the expression of one or more efflux pumps, such as P-glycoprotein, and is a major obstacle in cancer therapy. The use of new potent and noncytotoxic efflux pump modulators, coadministered with antineoplastic agents, is an alternative approach for increasing the success rate of therapy regimes with different drug combination...

The authors regret. 3. Results and discussion. Page 5, 1st column, 2nd paragraph. Revised to: “In the ¹H NMR spectra, two signals of vinylic protons at δH 6.07 (d, J = 10.4 Hz) and 5.83 (dd, J = 10.4, 3.7 Hz) appeared, assigned to H-1 and H-2 by the COSY correlations between them. In the ¹³C NMR spectra, two signals for oxygenated carbons at δC 75....

Carbohydrates can be used as substrates to synthesize new complex molecules; these molecules contain several chiral centers that can be used in organic synthesis. d-Fucose diphenyl thioacetal reacts differentially with acetone, and this paper describes a study of the mechanism of this reaction using theoretical chemistry methods. The conformer dist...

Jalapinoside II, a macrocyclic bidesmoside resin glycoside with purgic acid C as its oligosaccharide core, was isolated by recycle preparative-scale HPLC from the MeOH-soluble extract of Ipomoea purga (Convolvulaceae), the officinal jalap root (" Rhizoma Jalapae "). This study also reports the complete NMR data assignment for purgic acid C and the...

Recycling liquid chromatography was used for the isolation and purification of resin glycosides from the CHCl3-soluble extracts prepared using flowers of Ipomoea wolcottiana Rose var. wolcottiana. Bioassay-guided fractionation, using modulation of both antibiotic activity against multidrug-resistant strains of Gram-negative bacteria and vinblastine...

Teotihuacanin (1), an unusual rearranged clerodane diterpene with a new carbon skeleton containing a spiro-10/6 bicyclic system, was isolated from the leaves and flowers of Salvia amarissima. Its structure was determined through spectroscopic analyses. Its absolute configuration was established by single-crystal X-ray diffraction. Compound 1 showed...

The first macrocyclic bisdesmoside resin glycoside, jalapinoside (4), was purified by preparative-scale recycling HPLC from the MeOH-soluble extracts of Ipomoea purga roots, the officinal jalap. Purgic acid C (3), a new glycosidic acid of ipurolic acid, was identified as 3-O-β-d-quinovopyranoside, 11-O-β-d-quinovopyranosyl-(1→2)-O-β-d-glucopyranosy...

Density functional theory (DFT) 1H–1H NMR coupling constant calculations, including solvation parameters with the polarizable continuum model B3LYP/DGDZVP basis set together with the experimental values measured by spectral simulation, were used to predict the configuration of hydroxylated 6-heptenyl-5,6-dihydro-2H-pyran-2-ones 1, 2, 4, and 7, allo...

The root of the plant Ipomoea purga, a morning glory native to Mexico and belonging to the medicinal herb complex known as "raiz de Jalapa" had never been phytochemically studied as a drug for the treatment of gastrointestinal disorders. Previous investigation of the aerial parts have led to the isolation of resin glycosides, derivatives of opercul...

Reinvestigation of the CHCl3-soluble extract from the flowers of Ipomoea murucoides, through preparative-scale recycling HPLC, yielded three pentasaccharides of 11-hydroxyhexadecanoic acid, murucoidins XVII-XIX, in addition to the known murucoidin III and V, all of which were characterized by NMR spectroscopy and mass spectrometry. These compounds...

Historical aspects on the use and production of Mexican species of Dactylopius (Hemiptera: Dactylopiidae) and Opuntia (Cactaceae: Opuntioidae), as well as on their origin, diversity and distribution were investigated. Main issues on the conservation of these taxa are discussed. The colorant of five species of Dactylopius was analyzed using high-per...

Commercial preparations of the Mexican herbal drug known as “miracle tea” (Packera candidissima and P. bellidifolia) have been profiled qualitatively by HPLC and GC-MS. Pyrrolizidine alkaloids were identified in the alkaloid extracts. The content of free PAs and their N-oxides was determined for a total of 22 samples and the results showed that the...

Commercial preparations of the Mexican herbal drug known as "miracle tea" (Packera candidissima and P. bellidifolia) have been profiled qualitatively by HPLC and GC-MS. Eremophilanes (3-7) were the major components found in the hexane-soluble fraction, while pyrrolizidine alkaloids (PAs) were identified in the alkaloid extracts. The content of free...

A protocol for stereochemical analysis, based on the systematic comparison between theoretical and experimental vicinal (1)H-(1)H NMR coupling constants, was developed and applied to a series of flexible compounds (1-8) derived from the 6-heptenyl-5,6-dihydro-2H-pyran-2-one framework. The method included a broad conformational search, followed by g...

Pescaprein XVIII (1), a type of bacterial efflux pump inhibitor, was obtained from the CHCl(3)-soluble resin glycosides of beach morning glory (Ipomoea pes-caprae). The glycosidation sequence for pescaproside C, the glycosidic acid core of the lipophilic macrolactone 1 containing D-xylose and L-rhamnose, was characterized by means of several NMR te...

The genus Dactylopius includes the group of insects historically used in Mexico as a source of natural red colorant, the cochineal color. Five species of Dactylopius collected in thirteen states of Mexico and two provinces of Argentina were analyzed using high-performance liquid chromatography with a photodiode array detector. This analysis allowed...

The structural reassignment, absolute configuration, and conformational behavior of the highly flexible natural product hypurticin (pectinolide E), 6S-[3'S,5'R,6'S-triacetoxy-1Z-heptenyl]-5S-acetoxy-5,6-dihydro-2H-pyran-2-one (1), were ascertained by a molecular modeling protocol, which includes extensive conformational searching, geometry optimiza...

A reinvestigation of the CHCl 3-soluble extract from flowers of the Mexican medicinal arborescent morning glory, Ipomoea murucoides, through preparative-scale recycling HPLC, yielded six new pentasaccharides, murucoidins VI-XI (1- 6), as well as the known pescaprein III (7), stoloniferin I (8), and murucoidins I-V (9- 13). Their structures were cha...

Purification of a CHCl3-soluble extract from seeds of the Mexican medicinal arborescent morning glory, Ipomoea intrapilosa, by means of preparative-scale recycling HPLC, yielded seven new resin glycosides, intrapilosins I-VII (1-7). Their structures were established through the interpretation of their NMR spectroscopic and FABMS data. All pentasacc...

The geometry and energy profiles of the mutarotation pathway present in the equilibrium of 6-deoxy-β-l-mannopyranosyl 2,4-dinitrophenylhydrazine (1a), 6-deoxy-l-mannose 2,4-dinitrophenylhydrazone (1b), and 6-deoxy-α-l-mannopyranosyl 2,4-dinitrophenylhydrazine (1c) were modeled by DFT calculations at B3LYP/6-31G(d) level affording ΔGDFT=0.000kcal/mo...

Mexican Jalap roots, a prehispanic medicinal plant complex still considered to be a useful laxative, can be found as an ingredient in some over-the-counter products sold by herbalists in contemporary Mexico. The drug is prepared from the dried roots of several morning glories, all of which have been identified as members of the genus Ipomoea. Analy...

Bioassay-guided fractionation of a CHCl (3) extract prepared from the Mexican medicinal plant Hyptis pectinata led to the isolation of four pyrones, pectinolides A-C ( 1-3) and H ( 4). Activity was tracked using cultured KB cells. Multidrug-resistant strains of Staphylococcus aureus were sensitive to pectinolide H ( 4; KB > 20 microg/mL) in the con...

Preparative-scale recycling HPLC was used for the complete resolution of a complex mixture of nor-secofriedelanes into five major peaks (I-V) from the sedative methanolic extracts prepared from the aerial parts of Galphimia glauca. Argentation chromatography was used to show peaks I, II, IV, and V to be mixtures of isomers around the E-ring double...

6-Deoxy-l-mannose diphenyldithioacetal (1) unexpectedly gave the rearranged products phenyl 3,4-di-O-acetyl-2-S-phenyl-1,2-dithio-6-deoxy-beta-l-glucopyranoside (9) and 3,4-di-O-acetyl-2,5-anhydro-6-deoxy-l-glucose diphenyldithioacetal (10) upon treatment with acetyl chloride, while 6-deoxy-l-mannose ethylenedithioacetal (3) yielded (4aR,6S,7S,8R,8...

Stereoselective syntheses of the naturally occurring, cytotoxic lactone spicigerolide and three nonnatural stereoisomers thereof are described. The commercially available sugar l-rhamnose was in all cases the chiral starting material. Key steps in each of these syntheses were asymmetric Brown allylations and ring-closing metatheses. The cytotoxic a...

Bioactivity-directed fractionation of the crude extract prepared from the medicinal Mexican plant Hyptis spicigera (Lamiaceae) tested on KB cells led to the isolation of spicigerolide (1). The structure for this novel cytotoxic compound was elucidated as 6R-[3S,4S,5S,6S-tetraacetyloxy-1Z-heptenyl]-5,6-dihydro-2H-pyran-2-one. The relative stereochem...

A stereoselective synthesis of pyrrolo[2,1-a]isoindol-5-ones is described. The synthesis takes place through a tandem Michael addition-intramolecular cyclization, by the base-promoted condensation of methyl N-phthaloylalaninate with conjugate acceptors at low temperature. The desired products were obtained in good yields as single isomers in only o...

Seven new labdane diterpenes with insecticidal properties were isolated from the aerial parts of Hyptis spicigera. Their structures were established on the basis of spectral (MS, 1H NMR, and 13C NMR) and chemical evidences as: 19-acetoxy-2alpha,7alpha, 15-trihydroxylabda-8(17),(13Z)-diene (1); 15,19-diacetoxy-2alpha, 7alpha-dihydroxylabda-8(17),(13...