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Biomedical subjects

A Marston

Publications and source records attributed to A Marston.

At least 19 recordsLinked to original sources
PubMed2005

Developments in the application of counter-current chromatography to plant analysis.

Counter-current chromatography is a very versatile separation technique which does not require a solid stationary phase. It relies simply on the partition of a sample between the two phases of an immiscible solvent system. Some of the more recent applications of the method to the separation of plant-derived natural products are described here. Crude plant extracts and semi-pure fractions can be chromatographed, with sample loads ranging from milligrams to grams. Aqueous and non-aqueous solvent systems are used and the separation of compounds with a wide range of polarities is possible. The technique is complementary to other chromatographic methods and is compatible with gradient systems. The possibilities for solvent selection are almost limitless but some guidelines for the choice of successful systems are presented.

Chromatography, Thin Layer↗
PubMed2005

3-Farnesyl-2-hydroxybenzoic acid is a new anti-Helicobacter pylori compound from Piper multiplinervium.

A new prenylated salicylic acid derivative, 3-farnesyl-2-hydroxy benzoic acid (1), was isolated from the leaves of Piper multiplinervium C. DC. (Piperaceae). It showed anti-Helicobacter pylori activity (MIC 37.5 microg/ml) and antimicrobial activity at MICs between 2.5 and 5 microg/ml against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Mycobacterium smegmatis, Pseudomonas aeruginosa and Candida albicans. Its structure was elucidated by means of MS, 1H and 13C NMR. The ethnomedical claim of Piper multiplinervium to treat stomach aches by the Kuna Indians of Panama may be justified by anti-Helicobacter pylori activity of its MeOH extract.

Anti-Infective Agents↗
PubMed2003

On-line identification of tropane alkaloids from Erythroxylum vacciniifolium by liquid chromatography-UV detection-multiple mass spectrometry and liquid chromatography-nuclear magnetic resonance spectrometry.

The bark of catuaba (Erythroxylum vacciniifolium Martius, Erythroxylaceae), a tree native to the northern part of Brazil, was investigated for its alkaloid content. With the aim of obtaining preliminary structure information on-line, the alkaloid extract was analysed by high-performance liquid chromatography coupled to diode array UV detection, to mass spectrometry and to nuclear magnetic resonance. Interpretation of on-line spectroscopic data obtained from this extract led to structural elucidation of six new alkaloids and partial identification of 18 potentially original alkaloids bearing the same tropane skeleton esterified in positions 3 and 6 by 1-methyl-1H-pyrrol-2-carboxylic acid and/or 4-hydroxy-3,5-dimethoxybenzoic acid.

Alkaloids↗
PubMed2003

Antifungal isopimaranes from Hypoestes serpens.

Five isopimarane diterpenes (7beta-hydroxyisopimara-8,15-dien-14-one, 14alpha-hydroxyisopimara-7,15-dien-1-one, 1beta,14alpha-dihydroxyisopimara-7,15-diene, 7beta-hydroxyisopimara-8(14),15-dien-1-one and 7beta-acetoxyisopimara-8(14),15-dien-1-one) have been isolated from the leaves of Hypoestes serpens (Acanthaceae). All compounds exhibited antifungal activity against both the plant pathogenic fungus Cladosporium cucumerinum and the yeast Candida albicans; two of them also displayed an acetylcholinesterase inhibition. The structures of the compounds were determined by means of spectrometric methods, including 1D and 2D NMR experiments and MS analysis.

Acanthaceae↗
PubMed2003

Triterpenoid saponins from the roots of Silene cucubalus.

A new triterpenoid saponin was isolated from the roots of Silene cucubalus and its structure was determined on the basis of one- and two-dimensional NMR spectroscopy as gypsogenin 3-O-beta-xylopyranosyl-(1-->3)-[beta-galactopyranosyl-(1-->2)]-beta-glucuronopyranoside. A known saponin, quillaic acid 3-O-beta-xylopyranosyl-(1-->3)-[beta-galactopyranosyl-(1-->2)]-beta-glucuronopyranoside, was also isolated.

Humans↗
PubMed2001

Screening of Malian medicinal plants for antifungal, larvicidal, molluscicidal, antioxidant and radical scavenging activities.

A total of 78 different extracts from 20 medicinal plants belonging to 14 plant families from Mali were tested for their antifungal, larvicidal, molluscicidal, antioxidant and radical scavenging activities. Dichloromethane, methanol, water and ethanol extracts were used. TLC autobiography for antifungal activity was run with Cladosporium cucumerinum and Candida albicans. Extracts were also tested on the larvae of the mosquitoes Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus. Molluscicidal activities were established with the snails Biomphalaria glabrata, Biomphalaria pfeifferi and Bulinus truncatus. beta-Carotene and DPPH solutions sprayed on TLC plates were used for antioxidant and radical scavenging assays. Of the extracts investigated, 20% were antioxidant and radical scavengers, 19% fungicidal, 30% were larvicidal and 11% were molluscicidal. Three of the plant extracts, from Cussonia barteri (Araliaceae), Glinus oppositifolius (Aïzoaceae) and Lannea velutina (Anacardiaceae) gave positive responses in all four tests.

Aedes↗
PubMed2001

A methylflavan with free radical scavenging properties from Pancratium littorale.

The isolation of 7,4'-dihydroxy-8-methylflavan (1) from the dichloromethane extract of Pancratium littorale stem was guided by an assay for free radical scavenging activity towards the 2,2-diphenyl-1-picryl-hydrazyl radical (DPPH). The structure of 1 was established by spectrometric methods including UV, EI mass spectrometry, 1H and 13C-NMR. The free radical scavenging properties of 1 were quantified in solution using spectrophotometry.

Flavonoids↗
PubMed2001

Study of two plants used in traditional medicine in Zimbabwe for skin problems and rheumatism: Dioscorea sylvatica and Urginea altissima.

Two plants used in Zimbabwean traditional medicine, Dioscorea sylvatica (Dioscoreaceae) and Urginea altissima (Liliaceae), produce mild inflammation and itching when rubbed on the skin. Investigations of the causes of these cutaneous reactions showed that raphides of calcium oxalate are, at least in part, responsible for the effects. Histamine could not be detected.

Histamine↗
PubMed2001

Five new prenylated stilbenes from the root bark of Lonchocarpus chiricanus.

Besides the known compounds longistylines C (1), D (2), and 3,5-dimethoxystilbene (5), five new prenylated stilbenes, named chiricanines A--E (3, 4, 6--8), have been isolated from the root bark of Lonchocarpus chiricanus. Their structures were resolved on the basis of spectrometric methods including (1)H, (13)C, and 2D NMR experiments and mass spectrometry. Compound 3 was the only prenylated stilbene to demonstrate antifungal effects against Cladosporium cucumerinum. Four of the isolated compounds showed toxic properties against larvae of the yellow fever-transmitting mosquito Aedes aegypti. Compound 5 was found to be as potent as rotenone in larvicidal dilution tests.

Aedes↗
PubMed2000

Lignans from Mosla scabra.

Two new cyclobutane-type lignans, named moslolignans A and B, together with two known ones, andamanicin and magnosalin, were isolated from the whole plant of Mosla scabra. Their structures were established as 1beta*,2beta*,3alpha*,4alpha*-1,2-dimethyl-3-(3- methoxy-4,5-methylene-dioxyphenyl)-4-(2,4,5-trimethoxyphenyl)-cycl obutane and 1beta*,2beta*,3alpha*,4alpha*-1,2-dimethyl-3-(2, 5-dimethoxy-3,4-methylenedioxyphenyl)-4-(2,4,5-trimethoxyphenyl)-cyclobu tane by spectroscopic methods. This is the first report of naturally-occurring cyclobutane-type lignans with asymmetrical substitutions.

Alkenes↗
PubMed2000

Molluscicidal saponins from Phytolacca icosandra.

Five monodesmosidic serjanic acid saponins and a monodesmosidic spergulagenic acid saponin were isolated from an aqueous extract of the berries of Phytolacca icosandra. A methanol extract of the berries furnished three bidesmosidic serjanic acid glycosides. Their structures were established by spectroscopic (ES-MS, 1H NMR, COSY, HSQC, HMBC, 13C NMR) and chemical methods. The molluscicidal, spermicidal and haemolytic properties of the saponins were investigated.

Animals↗
PubMed2000

Antifungal and larvicidal cordiaquinones from the roots of Cordia curassavica.

In addition to the known cordiaquinones A and B, two novel meroterpenoid naphthoquinones, named cordiaquinones J and K, have been isolated from the roots of Cordia curassavica. Their structures were elucidated by spectrometric methods including EI, D/CI mass spectrometry, 1H, 13C and 2D-NMR experiments. The four naphthoquinones demonstrated antifungal activities against Cladosporium cucumerinum, Candida albicans and toxic properties against larvae of the yellow fever-transmitting mosquito Aedes aegypti.

Aedes↗
PubMed2000

Antifungal and larvicidal compounds from the root bark of Cordia alliodora.

Two new natural products, a phenylpropanoid derivative characterized as 1-(3'-methoxypropanoyl)-2,4,5-trimethoxybenzene (1) and a prenylated hydroquinone, 2-(2Z)-(3-hydroxy-3,7-dimethylocta-2, 6-dienyl)-1,4-benzenediol (2), have been isolated from the root bark of Cordia alliodora. Both compounds exhibited antifungal properties against the phytopathogenic mold Cladosporium cucumerinum. The phenylpropanoid derivative (1), whose structure is closely related to beta-asarone, also demonstrated a marked activity against larvae of the yellow-fever-transmitting mosquito Aedes aegypti.

Antifungal Agents↗
PubMed2000

Application of high performance liquid chromatography coupled with ultraviolet spectroscopy and electrospray mass spectrometry to the characterisation of ellagitannins from Terminalia macroptera roots.

PURPOSE: Terminalia macroptera roots are used in Guinea-Bissau and other West African countries to treat infectious diseases like gonorrhoea. Previous work showed an ethanol extract of T. macroptera roots (T) to have an in vitro antimicrobial profile against Neisseria gonorrhoae (including resistant strains) and enteropathogenic agents. The most active fractions of this extract were identified as the diethyl ether (T2) and water (T5) fractions. The aim of the present study was the identification of major compounds present in T and simultaneously in T2 or T5. METHODS: The T extract and T2 and T5 fractions were analysed by high performance liquid chromatography coupled with ultraviolet photodiode array (LC-UV) spectroscopy and electrospray ionization mass spectrometry (ES-MS). These analyses indicated the presence of ellagitannin derivatives. In order to confirm the identities of the detected compounds, they were isolated from T2 and T5 by preparative chromatographic techniques and identified by spectroscopic methods including tandem mass spectrometry. RESULTS: By using LC-UV-ES-MS, four major compounds (ellagic acid, gallic acid, punicalagin, terchebulin) could be identified in the T extract. Three other compounds (3,3'di-O-methylellagic acid, 3,4,3',4'-tetra-O-methylellagic acid, terflavin A) were also isolated and identified. CONCLUSIONS: LC-UV-ES-MS is a useful technique for the analysis of mixtures containing ellagitannins.

Chromatography, High Pressure Liquid↗
PubMed1999

Gut rot.

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Humans↗
PubMed1998

Antifungal and larvicidal meroterpenoid naphthoquinones and a naphthoxirene from the roots of Cordia linnaei.

Three new meroterpenoid naphthoquinones, the known cordiaquinone B and a new naphthoxirene have been isolated from the roots of Cordia linnaei. Their structures were established by spectrometric methods including EI, D/CI and FAB mass spectrometry, 1H, 13C and 2D NMR experiments. The naphthoquinones showed activity against Cladosporium cucumerinum, Candida albicans and the larvae of the yellow fever-transmitting mosquito Aedes aegypti, while the naphthoxirene derivative was found to be inactive in the same bioassays.

Aedes↗
PubMed1997

Inhibition of 5 alpha-reductase and aromatase by the ellagitannins oenothein A and oenothein B from Epilobium species.

Species of the genus Epilobium (Onagraceae) have been investigated for their activity against 5 alpha-reductase and aromatase, two enzymes which are involved in the aetiology of benign prostatic hyperplasia (BPH). Activity-guided fractionation has led to the identification of two macrocyclic ellagitannins, oenothein A (1) and oenothein B (2), as the main constituents responsible for the inhibition of the two enzymes. Quantitation of oenothein B in 10 different species of Epilobium has shown that amounts of up to 14% in the crude plant extracts are possible.

5-alpha Reductase Inhibitors↗