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Dive into the research topics where Timothy Plowman is active.

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Featured researches published by Timothy Plowman.


Brittonia | 2004

Names, types, and distribution of neotropical species of Erythroxylum (Erythroxylaceae)

Timothy Plowman; Nancy Hensold

A list is provided of all 358 taxa ofErythroxylum described from the Neotropics through the year 2000, including type specimen citations, probable synonymy, geographic distribution, and designation of 41 new lectotypes and one new neotype. The list includes 187 accepted species, eight accepted varieties, 27 infraspecific names of uncertain status, and 136 synonyms. A searchable specimen database and type image archive may be accessed at www.fieldmuseum.org/research_collections/database.htm.


Economic Botany | 1990

Significance of the fungus balansia cyperi infecting medicinal species of cyperus (Cyperaceae) from Amazonia

Timothy Plowman; Adrian Leuchtmann; Carol Blaney; Keith Clay

At least two species of Amazonian sedges (piripiri, i.e., Cyperus articulatus andC. prolixus, Cyperaceae) are widely utilized for various medicinal purposes, including birth control and induction of labor, and in hallucinogenic preparations. Examination of herbarium specimens collected from throughout South America and of living specimens collected in Ecuador has revealed that plants are infected by the systemic, ascomycetous fungusBalansia cyperi. This fungus is classified in the Clavicipitaceae and is known to infect only six species ofCyperus, including both North and South American species. Pure cultures of the fungus were obtained from two species of piripiri from Ecuador andC. virens from southern USA, and grown in submerged liquid culture. Extracts of the liquid medium revealed several unidentified ergot alkaloids. Current and past pharmacological uses of ergot alkaloids are consistent with uses of piripiri, suggesting a fungal basis for the ethnobotanical utilization of piripiri in Amazonia.RésuméDos especies de Cyperus de Amazonía (Cyperus articulatus y Cyperus prolixus, Cyperaceae) tienen varios usos medicinales tales como anticonceptivos, inductores del parto, y alucinógenos. El examen de ejemplares de herbario colectados a través de Sudamérica y de plantas vivas colectadas en Ecuador ha demostrado que las plantas están infectadas por un hongo sistémico de la familia Clavicipitaceae (Ascomycetes):Balansia cyperi. La infección de este hongo se conoce únicamente en seis especies de Cyperus nativas de Norteamérica y de Sudamérica. Obtuvimos cultivos puros del hongo pertenecientes a dos especies de “piripiri” de Ecuador y deCyperus virens del sur de los Estados Unidos, los cuales fueron cultivados en medio liquido. Extractos del medio de cultivo revelaron varios alcaloides desconocidos del tipo ergot. Los usos medicinales actuates y pasados de estos alcaloides son consistentes con los usos del piripiri, lo que sugiere que el hongo es responsable del uso etnobotánico del piripiri en Amazonia.


Journal of Ethnopharmacology | 1979

The ethnobotany of Brugmansia

Richard Evans Schultes; Timothy Plowman

In 1973, Dr. Tommie Earl Lockwood presented a thesis to the Department of Biology of Harvard University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Biology. This thesis, embodying some five years of graduate studies, including very extensive field work, was entitled A Tuxonomic Revision of Brugmansia (Solanaceue). Done under the direction of Professor Richard Evans Schultes, it represents the first comprehensive and inclusive study of the biology of the solanaceous species which have usually been considered as belonging to a section or subgenus of Datum. In addition to many other biological and nomenclatural considerations, Dr. Lockwood offered convincing experimental and morphological evidence for the maintenance of Brugmansia as a genus distinct from Daturu. Since alI of the species are arborescent, they have frequently been referred to as the “tree Daturas”. All of the species are native to South America, although several are now widely cultivated in warm areas around the world as omamentals because of their striking beauty. Upon receiving his Ph.D. degree, Dr. Lockwood was named Assistant Professor of Botany and Director of the University’s herbarium in the University of Illinois at Urbana, Illinois. In 1975, while leading a botanical collecting trip with his students in Mexico, he was killed in an automobile accident. Professor Lockwood’s thesis will, it is hoped, be published in its entirety as a book. We are here offering one chapter --“Ethnobotany” because it represents undoubtedly the most thorough and authoritative discussion available on the aboriginal uses of this group of psychoactive plants which have been and are of extreme importance in the medical, religious and magical practices of many indigenous peoples of South America. We are deeply indebted to Mr. and Mrs. Vergil Lockwood of Proctor, Oklahoma, parents of the late Professor Lockwood, for their gracious permission to publish this section of the thesis. In presenting for publication this portion of Professor Lockwood’s thesis, we, his former teacher and a close friend and colleague, call attention to notes on the personality and work of this promising young scientist published in Economic Botany, 29 (1975) 4 5.


Tetrahedron Letters | 1985

Brunfelsamidine: a novel convulsant from the medicinal plant brunfelsia grandiflora

Helen A. Lloyd; Henry M. Fales; Mark E. Goldman; Donald M. Jerina; Timothy Plowman; Richard Evans Schultes

Abstract A convulsant isolated from Brunfelsia grandiflora is identified as pyrrole-3-carbox-amidine.


Brittonia | 1986

Four new species of Erythroxylum (Erythroxylaceae) from northeastern Brazil

Timothy Plowman

Erythroxylum simonis, E. pauferrense, E. bezerrae, andE. tianguanum from northeastern Brazil are described and illustrated, and their taxonomic and phytogeographic relationships are discussed.


Phytochemistry | 1985

Alkaloids of some south american erythroxylum species

Y.M.A. El-Imam; William C. Evans; Timothy Plowman

Abstract Fourteen South American species of Erythroxylum representing four sections of the genus were examined for tropane and related alkaloids. The alkaloid content of the dried material ranged from 0.002 to 0.20 %. Commonly, the alkaloids involved were esters of various tropanols with benzoic and phenylacetic acids. A new alkaloid, nortropacocaine, was isolated from E. mamacoca. Mass spectrometry indicated the existence of other new bases, cuscohygrine and, in some species dihydrocuscohygrine. Chemotaxonomic implications are discussed.


Phytochemistry | 1981

Fate of cocaine in the lymantriid Eloria noyesi, a predator of Erythroxylum coca

Murray S. Blum; Laurent Rivier; Timothy Plowman

Abstract Larvae of the lymantriid moth Eloria noyesi , which are obligate feeders on Erythroxylum coca , excrete most of the ingested cocaine as unchanged base. Cocaine, analysed by mass fragmentography, is readily, detectable in the blood of larvae and is presumably sequestered during larval feeding, since it is present in the bodies of adult moths that do not feed on E. coca . Cocaine is an effective feeding deterrent for the ant Monomorium pharaonis when present at a concentration below that found in the leaves of E. coca .


Phytochemistry | 1988

Flavonoid variation in Erythroxylum

Bruce A. Bohm; T. Loo; K.W. Nicholls; Timothy Plowman

Abstract Thirteen species of Erythroxylum from Brazil were studied for their flavonoids. All exhibit profiles based upon flavonol glycosides. Predominant flavonols are kaempferol, quercetin and 7,4′-dimethylquercetin. O -Methylated chalcones and flavanones were identified in E. cf. loefgrenii . This represents the first report of chalcones from the genus. Variation was observed in the number of compounds present in the profiles, the nature of the flavanols present, and in the degree of glycosylation of the flavonols. In the case of E. vacciniifolium three distinct flavonoid profiles were seen in specimens from different regions of Brazil.


Acta Amazonica | 1984

New taxa of Erythroxylum (Erythroxylaceae) from the Amazon basin.

Timothy Plowman

Three new species of Erythroxylumfrom Amazoniaare described: Enythroxylum nelson-rosaePlowman, E. schunkeiPlowman and E. tucuruiendePlowman. An emended des-cription is given for E; ligustrinum DC., previously know from a single collection from French Guiana: its is here cited from Brazil for the first time. A new variety, E. ligustrinum var. carajasensePlowman, is also described. A provisional list of all Erythroxylum species occurring in Amazonia and peripheral areas is appended.


Journal of Ethnopharmacology | 1982

The effects of field preservation on alkaloid content of fresh coca leaves (Erythroxylum spp.)

Michael J. Balick; Laurent Rivier; Timothy Plowman

In order to test the effects of commonly used preservation agents on the alkaloid content of herbarium specimens, fresh leaves of Erythroxylum coca, E. novogranantense, and E. novogranatense var. truxillense were air-or heat-dried or treated with six different liquid preservatives. The leaves were then extracted and analyzed quantitatively for cocaine content. Leaves which were soaked in preservatives showed appreciable pre-extraction of cocaine and probably of other alkaloids. The results compare well with a similar experiment conducted on flavonoid content of the leaves of a palm Jessenia bataua. If portions of herbarium specimens are to be useful for phytochemical screening using microtechniques, at least part of the collection must be air- or heat-dried to retain the chemical constituents.

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Laurent Rivier

Medical Research Council

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Adrian Leuchtmann

Indiana University Bloomington

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Carol Blaney

Indiana University Bloomington

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Donald M. Jerina

National Institutes of Health

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Helen A. Lloyd

National Institutes of Health

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Henry M. Fales

National Institutes of Health

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Keith Clay

Indiana University Bloomington

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Lorin I. Nevling

Field Museum of Natural History

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