Parthenium argentatum

The hypothesis of Gray and Bonner (31, 32) that 3-acetyl-6-methoxybenzaldehyde, which is found in the leaves of Encelia farinosa and in the soil beneath these plants, is responsible for the suppression of other plant species has not been substantiated by Muller (33, 34). The same is true for the presumed role of trans-cinnamic acid in "soil sickness associated with guayule (Parthenium argentatum), for the amygdalin of peach roots, and for the phlorizin of apple roots or its breakdown products (35), which were thought to be associated with the "soil sickness" of orchards. 

Rubber obtained from the shrub, Parthenium argentatum, native to north central Mexico and the adjacent part of Texas. The rubber is not obtained by tapping but by harvesting the shrubs and crushing the woody tissue to separate it from the rubber. Intensive research, started in 1942, has not succeeded in making guayule competitive with Hevea rubber, and since 1962 there has been no commercial production. 

The chlorination of low molecular weight natural rubber from Guayule (Parthenium Argentatum Grey) has been accomplished. The structure of the chlorinated product is consistent with that of chlorinated Hevea rubber. The use of Azo-bis-isobutyronitrile was as a catalyst resulted in increased chlorine content with a concomitant reduction in molecular weight, thereby allowing the preparation of lower viscosity grades of chlorinated rubber. 

Lloyd, F. E. "Guayule ( Parthenium argentatum Gray) A rubber-plant of the Chihuahuan Desert". Carnegie Institute of Washington, 1911, 213 pp. 

The sesquiterpene phenolic esters, guayulin A (4) and -B (5) from the desert rubber plant guayule (Parthenium argentatum) were found to be relatively... 

Ji, W., Benedict, C.R. and Foster, M.A. (1993) Seasonal variations in rubber biosynthesis, 3-hydroxy-3-methylglutaryl-coenzyme A reductase and rubber transferase activities in Parthenium argentatum in the Chihuahuan Desert. Plant Physiol, 103, 535-42. 

NR belongs to a class of compounds known as elastomers [5]. NR was used for centuries by the Mayans in the Western hemisphere before it was introduced into Europe by Columbus. The term rubber was, however, coined by Joseph Priestly. NR is indispensable in our daily lives. The main uses of NR are concentrated in four key areas, namely medical devices, industrial products, domestic and recreational goods, and foremost automobile products. The current elastomer consumption in the world is 18 million t per year [6]. NR supplies about one-third of the world demand for elastomers. It is also used as an industrial raw material. NR is a naturally occurring elastomeric polymer of isoprene (2-methyl-l,3-butadiene). It can be extracted from latex of only one kind of tree, Hevea braziliensis. Hevea rubber is produced in many tropical regions of Southeast Asia, Africa and Central and South America. There is practically only one other potential source of NR, that is the guayule shrub (Parthenium argentatum). 

Namral Rubber (NR) is a well-known example of a polymer emulsion made by namre. A relatively broad number of different plants produce a rubber-containing latex, but only Hevea Brasiliensis and, to a much lower extent, the Guayule plant, Parthenium Argentatum, the roots of Kok-Saghys, Taraxacum Bicorne, and the... 

Asteraceae Parthenium argentatum North Mexico Shrub Guayule (Mexican) rubber... 

In the original scenario, potential rubber crops were considered. Since then, it was decided to develop guayule (Parthenium argentatum) as a domestic source for natural rubber (1. The U.S. rubber market can potentially be supplied by guayule grown in the southwest. Thus, barring discovery of an... 

Commercial rabber has been isolated from Castilla elas-tica (Moraceae), Manihot glaziovii (Euphorbiaceae), Lan-dolphia spp. (Apocynaceae), Taraxacum kok-saghyz (As-teraceae), Hevea brasiliensis (Euphorbiaceae), and Parthenium argentatum (guayule, Asteraceae). Despite intense interest in finding other rabber sources, virtually all commercial natural rabber comes from Hevea brasiliensis or closely related species (Euphorbiaceae) (Rogers, 1981). 

Reddy, R. and Das, Chloroplast autonomy for the biosynthesis of isopentenyl diphosphate in guayule Parthenium argentatum. Gray), New Phytologist, 106, 457-464 (1987). 

Compound released from roots of Parthenium argentatum causing self inhibition of growth Inhibitor of spore germination in rusts (Puccinia, Uromyces)... 

Table 4. Protein Content of Latex from Parthenium argentatum and Hevea brasiliensis, Determined Using a Modified Micro-BCA Assays...

Partheniol, 8a-hydroxybicyclogermacrene (108) isolated from Parthenium argentatum x Parthenium Tometosa, was cultured in the media of Mucor circinelloid.es ATCC 15242 to afford six metabolites, a humulane (109), three maaliane- (110,112,113), an aromadendrane- (111), and a tricylohumulane triol (114), the isomer of compound (111). Compounds 110, 111, and 114 were isolated as their acetates (Figure 15.36). 

Taxonomy Cycloartane Triterpenoids Parthenium argentatum Gray (Compositae) [1-3],... 

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