Winston Tinto

• BSc., PhD.
• Professor at University of the West Indies

Cellulolytic bacteria that produce cellulases, which are active over a range of pH and temperatures, can be used to catalyze hydrolysis of pretreated lignocellulosic material. This is important in the production of second generation biofuels among other biotechnological applications. In this investigation, bacteria isolated from sugarcane bagasse w...

Plants belonging to the genus Aspidosperma, a member of the family Apocynaceae, provide a rich source of β-carboline alkaloids, which makes them potentially poisonous. However, some of these alkaloids possess antitumor and antimicrobial activity. The present review is a survey of the β-carboline alkaloids and shows that they comprise of a diverse a...

Ecuadorin (1), C29H34O10, a novel tetranortriterpenoid, has been isolated from Guareakunthiana (Meliaceae) collected in Ecuador. Its structure has been established by spectroscopic methods, mainly 2-D NMR spectroscopy; the value of the FLOCK pulse sequence in the determination of 2- and 3-bond 13C–1H connectivities is illustrated. Ecuadorin has bee...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Three new cassane diterpenes (1-3) were isolated from Caesalpinia pulcherrima. The structures of the isolated compounds were assigned based on spectroscopic and spectrometric analysis.

Four new echinocystic acid glycosides (1-4) were isolated from the dried seeds of Albizia lebbeck. The alkaline hydrolysate of the saponin fraction yielded two new prosapogenins (5-6). Their structures were determined by extensive NMR and spectroscopic analysis.

Chemical studies carried out on Clerodendrum chinense yielded three new compounds including the steroid (22E, 24S)-stigmasta-4, 22, 25-trien-3-one (1), the flavone glycoside 7, 8, 4′-trihydroxyflavone-6-O-β-D- glucuronopyranoside (2) and the epimeric neo-clerodane 14, 15-dihydro-15ξ- hydroxyclerodendrin A (3). Two acetylated derivatives of compound...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

A chemical investigation of Aspidosperma excelsum yielded excelsinidine (1), a quaternary indole alkaloid possessing an unusual l-azoniatricyclo[4.3.3. 0]undecane moiety, along with the known compound aspidodasycarpine (2). Structural elucidation was effected by a combination of ID- And 2D-NMR spectroscopic techniques, along with mass spectral stud...

A chemical study of the bark of Sapium hippomane (Euphorbiaceae), obtained in the parish of St. John, Barbados, led to the isolation of two new phorbol esters (1 and 2), in addition to the known compound 4-deoxyphorbol (3). Compounds 1 and 2 were C-4 epimers, with a tigliane-type skeleton possessing C5 esters at C-12 and C-13. Chromatographic metho...

Plants belonging to the family Agavaceae are used in folkloric medicinal practices worldwide and chemical investigations of these plants have shown that they are an abundant source of steroidal saponins and sapogenins. Despite the large number of secondary metabolites isolated from this family so far, there have been few reports on the bioactivity...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

A chemical investigation of the bark of Simarouba amara, collected in Barbados, resulted in the isolation of six new triterpenes (3-8), in addition to two known compounds, 3-oxatirucalla-7, 24-dien-23-ol (1) and niloticin (2). Compound 3 is a tirucallane triterpene, while compounds 4-7 are apotirucallane derivatives containing an epsilon-lactone in...

An investigation of Agave americana and Agave barbadensis resulted in the isolation of a new homoisoflavanoid, 7-hydroxy-3-(4-methoxybenzyl)-chroman (3), together with known compounds 7-hydroxy-3-(4-methoxybenzyl)-chroman-4-one (1), 5,7-dihydroxy-3-(4-methoxybenzyl)-chroman-4-one (2), cantalasaponin-1 (4), and 2-hydroxy-butanedioic acid-1-methyl es...

Four steroidal saponins were isolated from the leaves of Furcraea selloa var. marginata. These included one furostanol saponin, furcreafurostatin (1), and three known spirostanol saponins, furcreastatin (3), yuccaloeside C (4) and cantalasaponin-1 (5). The 22-O-methyl ether (2) of furcreafurostatin (1) was also characterized. The structures were de...

The stem bark of Salacia cordata has afforded 28-hydroxylup-20(29)-en-3-one, 30-hydroxylup-20(29)-en-3-one, betulin, pyracrenic acid, and a new compound, 15, 28-dihydroxylup-20(29)-en-3-one [3]. Two-dimensional nmr methods have been used to assign structures and nmr spectra.

Two new triterpenes, the trihydroxy ketone 1 and the corresponding diosphenol 2 have been isolated from the leaves of Jatropha gossypiifolia (Euphorbiaceae). Structures have been assigned by 2D nmr spectroscopy; the value of the FLOCK pulse sequence is illustrated.

Sumaresinolic acid [1] and 3-epi-sumaresinolic acid [2], a new natural product, have been isolated from Miconia stenostachya (Melastomataceae). The C-13 and H-1 chemical shifts of these compounds and a number of their derivatives have been assigned from 2D nmr spectra in which the FLOCK pulse sequence was used to establish 2- and 3-bond H-1-C-13 co...

An investigation of the Stems and bark of Peritassa compta has led to the isolation of three new natural products, friedelane-3,15-dione [3], 15alpha-hydroxyfriedelin [4], and 15alpha-hydroxyfriedelane-1,3-dione [5), along with friedelin [1] and friedelane-1,3-dione [2]. Complete H-1 and C-13 assignments for all compounds were achieved by 2D nmr sp...

We have reinvestigated the leaves and roots of Trichilia schomburgkii and, in addition to a number of known triterpenes, we have re-isolated 2beta,3beta,4beta-trihydroxypregnan-16-one [1] along with the new stereoisomer 2alpha,3alpha,4beta-trihydroxypregnan-16-one [2].

Three quassinoids, 6alpha-tigloyloxychaparrinone [1], 6alpha-tigloyloxychaparrin [2], and 6alpha-hydroxychaparrinone [3], have been isolated for the first time from Quassia multiflora. Compounds 1 and 2 were previously isolated from other members of the Simaroubaceae, while this is the first reported natural occurrence of 3. Structural assignments...

A new tetrahydroxysterol, acerosterol [2], has been isolated from the gorgonian octocoral Pseudopterogorgia acerosa. The structure has been determined to be 4alpha,23,24(R)-trimethyl-5alpha-cholest-22E-ene-1alpha,3beta,6beta,11alpha-tetraol on the basis of 2D nmr spectroscopy.

Two new sesquiterpene alkaloids, peritassines A [1] and B [2], and the known compounds euonine [3], ebenifoline W-I [4], euojaponine F[5], and wilforine [6], were isolated from the stems and bark of Peritassa compta. The structures of 1 and 2 were elucidated by high resolution nmr spectroscopy.

Erythropodium caribaeorum obtained off the coast of Tobago has yielded the known diterpenes erythrolide A [1], erythrolide B [2], and erythrolide E [3] as well as a new diterpene designated erythrolide J [4]. The structure of compound 4 was determined by high resolution nmr studies.

A new pseudopteranoid, 11-gorgiacerol [2], has been isolated, along with previously described pseudopteranoids, from Pseudopterogorgia acerosa. The structure of 2 was established by 2D nmr spectroscopy.

A new glabretal-type triterpene [1], was isolated from the roots of Quassia multiflora. Its structure was established by a combination of 2D nmr experiments.

A new labdane diterpenoid, leonotinic acid (1), possessing an alpha,beta-butenolide unit, was isolated from the aerial parts of Leonotis nepetaefolia. It was identified on the basis of 1D and 2D NMR including H-1-H-1 COSY, HSQC, HMBC and T-ROESY spectroscopic techniques.

A chemical investigation of the Caribbean marine octocoral Eunicea laciniata collected along the south coast of Barbados afforded a new cubitane diterpenoid (1), a new steroidal glycoside (3), along with two known diterpenes. Their structures were determined by 1D and 2D NMR spectral experiments.

Seven new labdane diterpenes, sibiricinones A-E (1-4, 6) and 15-epi-sibiricinones D and E (5 and 7), and the flavone genkwanin were isolated from the aerial parts of Leonurus sibiricus. Sibiricinone D (4) and 15-epi-sibiricinone D (5), and sibiricinone E (6) and 15-epi-sibiricinone E (7), respectively, were isolated as C-15 epimeric pairs. These se...

A chemical investigation of the Caribbean marine octocoral Eunicea laciniata collected along the south coast of Barbados afforded a new cubitane diterpenoid (1), a new steroidal glycoside (3), along with two known diterpenes. Their structures were determined by I D and 2D NMR spectral experiments.

Three pyrones and a 2(5H)-furanone, designated pectinolides D-G, have been isolated from the dichloromethane extract of Hyptis pectinata. The metabolites were characterized on the basis of 1D and 2D NMR spectroscopic techniques. The pyrones were identified as 6S-[3S,6S-(diacetoxy)-5R-hydroxy-1Z-heptenyl]-5S-hydroxy-5,6-dihydro-2H-pyran-2-one (1)- p...

Three pyrones and a 2(5H)-furanone, designated pectinolides D–G, have been isolated from the dichloromethane extract of Hyptis pectinata. The metabolites were characterized on the basis of 1D and 2D NMR spectroscopic techniques. The pyrones were identified as 6S-[3S,6S-(diacetoxy)-5R-hydroxy-1Z-heptenyl]-5S-hydroxy-5,6-dihydro-2H-pyran-2-one (1)- p...

Five new cassane diterpenoids (1-5) were isolated from the roots of Caesalpinia pulcherrima, along with the known isovouacapenol C (6), pulcherrimin A (11), and 6beta-cinnamoyl-7beta-hydroxyvouacapen-5alpha-ol (12). Compounds 3-5 possess the alpha,beta-butenolide moiety, whereas compounds 1 and 2 contain a more usual 2,3-disubstituted furan unit. C...

An investigation of the Caribbean octocoral Eunicea tourniforti collected along the southwest coast of Barbados afforded four new cembrane diterpenes, 1, 2, 4, and 5, along with the known cembranolide 3. The structures of all metabolites were determined by spectroscopic methods. Seasonal effects on the secondary metabolite content of the specimens...

An investigation of the gorgonian octocoral Erythropodium caribaeorum collected off the north coast of Jamaica has yielded three new briarane diterpenes. In addition, the six known diterpenes, erythrolides A, B, D, E, F, and I were isolated. The structures of these diterpenes were established by 1H and 13C NMR spectroscopy utilizing DEPT, COSY, and...

Seven cassane diterpenes, including the known caesaldekarin A, were isolated from the roots of Caesalpinia bonduc, collected in Barbados. The 1H and 13C NMR spectra of all seven compounds were completely assigned by using a combination of 2D NMR experiments, which included 1H-1H COSY, HSQC, HMQC, and HMBC sequences.

Two new cyclodepsipeptides, geodiamolide H (3) and I (4), were isolated from the marine sponge Geodia sp. The structures of 3 and 4 were determined by 2D NMR spectroscopy while the absolute stereochemistry of 4 was established by X-ray crystallography. Geodiamolide H 3 was cytotoxic to some human cancer cell lines.

Two new cassane diterpenes, named caesaldekarins F and G, were isolated and identified from the roots of Caesalpina boducella. The recently reported caesaldekarin C was also isolated from the roots of this plant. The structures of caesaldekarins F and G were established by the use of 2D NMR spectroscopy.

Four cassane furanoditerpenes, including the known α-caesalpin and caesalpin F, were isolated from the roots of Caesalpinia boducella. The 1H and 13C NMR spectra of all four compounds were completely assigned by using a combination of 2D NMR experiments, which included 1H–1H COSY, HMQC, HMBC and NOESY sequences. © 1998 John Wiley & Sons, Ltd.

A number of cassane diterpenes were isolated form the medicinal plant Caesalpinia bonducella. Separation of the ethanolic extract was executed via Preparative Layer Chromatography, Flash Chromatography and HPLC. Structure elucidation included IR, UV, 1D/2D 1-HNMR and 13-CNMR with COSY, HMBC and NOESY experiments.

A new 5,8-diazabenz[cd]azulene alkaloid, aaptosamine, was isolated from the marine sponge Aaptos aaptos collected in the southern Caribbean. The structure was determined by 2D NMR spectroscopy using HMQC and HMBC experiments. The known alkaloid 9-demethyloxyaaptamine which was isolated from an earlier collection of A. aaptos, underwent an unprecede...

A new rearranged cassane furanoditerpene, caesalpinin B, was isolated from the roots of Caesalpinia bonduc, collected in Barbados, West Indies. The structure was established on the basis of spectroscopic data, including 2D NMR spectroscopy.

Two new pyrrole alkaloids, axinellamines A and B, were isolated from the Caribbean marine sponge Axinella sp. and their structures were established on the basis of spectroscopic data, including 2D NMR spectroscopy. Axinellamine A was determined to be 2-((E, E)-6-methyl-2,4-octadienyl)pyrrole while axinellamine B was a dimer of axinellamine A, but c...

Four cassane furanoditerpenes, designated bonducellpins A (1), B (2), C (3), and D (4), were isolated from the roots of Caesalpinia bonduc. The 1H- and 13C-NMR spectra of all four compounds were completely assigned by using a combination of 2D NMR experiments, which included COSY, HMQC, HMBC, and NOESY sequences.

Three prenylated flavonoids and a hydroxy fatty acid were isolated from the leaves of the seedless variety of Artocarpus communis, but only one from the leaves of the seeded variety. Two of these compounds are known to show great promise as pharmaceutical and agricultural chemicals. The 1H and 13C NMR spectra were completely assigned by using a com...

Eight new diterpenes were isolated from Briareum asbestinum collected off south-west Tobago. Six metabolites (4) – (9) are briareolate esters while (10) and (11) are related to the briareolides. The structures of all compounds were determined by 2D NMR spectroscopy and correlation with known compounds. The structure of compound 4 was confirmed by X...

Three new squalene triterpenes, quassiols B (2), C (3) and D (4), were isolated from the roots of Quassia multiflora. Their structures were established by a combination of 2D NMR experiments, which included DQF-COSY, HMQC, HMBC and NOESY sequences.

A new alkaloid, axinellamide (1), was isolated from the marine sponge Axinella sp. collected off the coast of Trinidad. The structure was determined by 2D-NMR spectroscopy to be 5-hydroxy-5-((E,E)-6-methyl-2,4-octadienyl)-3-pyrrolin-2-on.

A new bisabolane sesquiterpene, (-)-curcuhydroquinone-1-monoacetate [1], was isolated from Barbadian Pseudopterogorgia americana along with the known (-)-curcuhydroquinone [2], (-)-curcuphenol acetate [3], and (-)-curcuquinone [4]. Compound 2 was also isolated from P. acerosa. The structures of all compounds were confirmed by the use of HMQC and HM...

A new sterol with a 9,11-seco dinostane nucleus was isolated from Pseudopterogorgia americana and its structure determined by a combination of 2-D NMR experiments.

Three new bitter saponins, designated mabioside A, B and C, were isolated from the bark of Colubrina elliptica and were determined to be 3-O-[-JL-rhamnopyranosy]-(1 → 6)-β-D-glucopyranosyl-15-O-[β-D- glucopyranosyl] mabiogenin, 3-O-[-L-rhamnopyranosy]-(1 → 6)-[β-D-glucopyranosyl-(1 → 2)]-β-D-glucopyranosyl}mabiogenin and 3-O-[-L-rhamnopyranosyl-(1...

(24R)-24-Methyl-21,24-oxylanost-9(11)-en-3-one, C31H50O2, M(r) = 454.7, orthorhombic, P2(1)2(1)2(1), a = 7.135 (3), b = 17.639 (4), c = 21.454 (7) angstrom, v = 2700.1 (16) angstrom3, Z = 4, D(x) = 1.12 g cm-3, lambda(Mo Kalpha) = 0.70930 angstrom, mu = 0.6 cm-1, F(000) = 1008, room temperature, R = 0.052 for 1519 observed reflections. The structur...

A new squalene triterpene (1), possessing a tetrahydrofuran moiety was isolated from the roots of Quassia multiflora. The structure was established by a combination of 2D NMR experiments.

The structure was elucidated by 2D NMR and X-ray crystal-structure analysis, which also established the relative stereochemistry. This is the first briarein diterpene containing a C-19 methyl ester.

A new tyramine derivative, hortiamide [1], was isolated from the roots of Hortia regia, The structure was determined from a series of 2D nmr experiments.

The biologically active butyrolactone (-)-trachelogenin [1] has been isolated from the leaves of Glycydendron amazonicum. The 13C-nmr assignments have been revised on the basis of a 2D nmr analysis.

Three C31 triterpenoids, formally derived from 24-methyllanostane, have been identified in the leaves of Oxandra asbeckii. The structures of two of these compound were assigned as 3, 2,3-dioxo-oxandrane, and 4, 3-hydroxyoxandrane, on the basis of the spectroscopic characteristics of the natural products and their derivatives. Two-dimensional nmr me...

Complete 1H and 13C spectral assignments are reported for peridinin, the major dinoflagellate carotenoid responsible for ‘red tides’ in the ocean. These assignments were made with the aid of HETCOR, FLOCK and COSY 2D spectra and NOE difference spectra.

The structures of seven pseudopteranoids isolated from the Caribbean octocoral have been investigated by 2-D NMR spectroscopy using our FLOCK, pulse sequence to determine - bond connectivities. Six of the compounds (-) are new.

The structure of was elucidated by 2-D nmr methods and confirmed by X-ray crystal-structure analysis, which also established the stereochemistry (relative configuration). The compound is an unusually stable diepoxyfuran derivative.

The structures of hyeronimone [3] and its acetate 4, isolated from the roots of Hyeronima alchorneoides, have been established, mainly on the basis of 2D nmr spectroscopy. Aquilegiolide [1], a rare butenolide, was isolated from the leaves of the plant, which also afforded lupeol, stigmasterol, and a sitosterol.

The diterpenes abbeokutone [1] and 1,2-dehydroabbeokutone [2] have been isolated from Glycydendron amazonicum. Two-dimensional nmr spectroscopy has been used to make structural and spectroscopic assignments. A small amount of 1,6-dimethyl-2,7-dimethoxyanthraquinone [3], a new compound, was also isolated.

From Trichilia schomburgkii, we have isolated three protolimonoids (niloticin, dihydroniloticin, and piscidinol A), the limonoid 7-deacetoxy-7-oxogedunin, phytosterols, and the new compounds 2,3,4-trihydroxypregnan-16-one [9] and 2-(13-phenyltridecyl)-3-hydroxy-4-methylbutanolide [7]. Two-dimensional nmr spectroscopy has been used to establish the...

The diterpenoid metabolites isolated from Pseudopterogorgia acerosa collected off the coast of Tobago have been investigated. Collections made in the month of March showed a different distribution of these metabolites from a collection made in July. The dominant constituents in March were acidic diterpenoids which were converted by reaction with di...

Six new diterpenes, (1–3 and 5–7), were isolated from Briareum asbestinum collected off the coast of Tobago, West Indies. Their structures were determined by a combination of 2D NMR experiments.

Two new and five known germacrane derivatives were isolated from and a related species. Their structures were established by spectroscopic methods.

2-D NMR spectroscopy has established the structure of tobagolide, isolated from , as the novel dimethylamino derivative . Acetylation of follows an unusual course in which NMe2 is replaced by OAc.

Three new cembranoids, dihydroplexaurolone (2) and two dehydroplexaurolones (3) and (4), have been isolated from the gorgonlan Plexaura A. The structure of 2 was established by X-ray crystallographic studies. Crystals of 2 belong to space group P21, with a = 10.711 (2) A, b = 10.976 (3) A, c = 17.148 (4) A, β = 99.99 (2)°, and Z = 4. The structure...

Two novel cyclodepsipeptides, geodiamolides A (1) and B (2), were isolated from the marine sponge Geodia sp. and their stereostructures determined by X-ray crystallography. The geodiamolides contain a tripeptide unit of two (S)-alanines and a (R)-3-halotyrosine joined to a polypropionate unit in an 18-membered ring; the halogens are iodine and brom...