Guayule byproduct evaluation: extract characterization

Schloman, William W.; Hively, R. A.; Krishen, Anoop.; Andrews, Anne M.

doi:10.1021/jf00118a050

Cited by 75 publications

(47 citation statements)

References 9 publications

(18 reference statements)

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“…Table 4 reports the analytical data obtained for the RP-HPLC determination of guayulins A, B, C and D in acetone and ethanol ASE extracts from different Guayule biomass (leaves (L samples), fine stems (FS samples) and coarse stems (CS samples)) harvested in January 2015 (dried samples, 1) and in September 2015 (fresh samples, 2). While data relative to guayulins A and B are roughly comparable with those previously reported in literature [4,6,10,11], those relative to the amounts of guayulins C and D in acetone (or ethanol) extracts by different parts of the Guayule shrub are, to the best of our knowledge, unprecedented at all. Firstly, it is very important to highlight that these data are relative to a spontaneous Guayule shrub, whereas almost all literature data are relative to specific and well-known Guayule genotypes coming from cultivation.…”

Section: Analysis Of the Resin Extractssupporting

confidence: 88%

“…An acetonitrile:water 80:20 (v:v) solution provided the best results. In addition, the acquisition of chromatograms in the wavelength range between 250 nm and 280 nm demonstrates that the best compromise among different UV maximum absorptions of the analytes is the λ at 262 nm, as previously reported in the literature [4,6,10,11]. Table 2 summarizes the operating conditions of the chromatographic method proposed.…”

Section: Assessment Of the Chromatographic Methodsmentioning

confidence: 56%

“…Despite the fact that it is often not valorized and hence discarded, resin is a very interesting fraction from both an academic and an industrial point of view. Indeed, it is not only rich in sesquiterpenoids and triterpenes of potential commercial value [6], it also contains a variety of interesting secondary metabolites of the shrub, like guayulins [6][7][8] ((1S,2E,6E,9S,10R)-3,7,11,11-tetramethylbicyclo[8.1.0]undeca-2,6-dien-9-ol) [7], whereas the guayulin C ((1AR,1BR,2R, 4AR,7S,7AR)-2-hydroxy-1,1,2-trimethyl-5-methylidene-decahydro-1H-cyclopropa [E]azulen-7-yl (2E)-3-phenylprop-2-enoate) and guayulin D ((1AR,1BR,2R,4AR,7S,7AR)-2-hydroxy-1,1,2-trimethyl-5-methylidene-decahydro-1H-cyclopropa[E]azulen-7-yl 4-methoxybenzoate) are likely formed by the oxidation of the guayulines A and B, respectively [6,8]. Scheme 1 reports the structures of these molecules.…”

Section: Introductionmentioning

confidence: 99%

“…The wide variability in the amounts of guayulins A and B in the resin depends on a number of factors, such as: soil nature, climate, phenological phases, cultivar, age and, mainly, the nature of the different parts of the shrub [10,11]. On the other hand, the concentrations of guayulins C and D in resin seems to be much lower than those of guayulins A and B. Schloman et al estimated that the amounts of guayulins C and D in resin are between 50% and less than 10% of the amount of the guayulin A and B, respectively [6]. Guayulins likely act as cinnamate and p-anisate reservoirs for the Guayule shrub: when it is required by the plant, a metabolic turnover releases the corresponding free acid [4].…”

Section: Introductionmentioning

confidence: 99%

“…Obviously, chromatographic methods are dominant in the analytical characterization of such analytes and, among them, HPLC is the preferred approach. While few papers reported the presence of guayulins C and D in extracts from resin [6,8,11], the quantification of these analytes has been never simultaneously carried out to that of guayulins A and B [6,8]. Hence, it is evident that at present a validated HPLC procedure aimed to simultaneously quantify the amounts of all known guayulins is not reported in literature.…”

Section: Introductionmentioning

confidence: 99%

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Assessment, Validation and Application to Real Samples of an RP-HPLC Method for the Determination of Guayulins A, B, C and D in Guayule Shrub

et al. 2018

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Guayule (Parthenium argentatum Gray) is a shrub native to the arid regions of Mexico. In the last decades, significant attention to its cultivation has arisen because it is the raw material for the production of hypoallergenic natural rubber. Guayule biomass also contains high amounts of resin, which is not normally exploited in any way. Among other sesquiterpenic esters, guayulins (i.e., the parteniol esters of cinnamic acid, guayulin A, or of anisic acid, guayulin B) are contained in resin. In addition, minor amounts of guayulin C and guayulin D are formed by degradation/oxidation of guayulins A and B, respectively. Guayulins likely act as cinnamate and p-anisate reservoirs for the Guayule shrub; in addition, it has been postulated that they might have a key role in the chemical defense system of Guayule. Furthermore, it seems reasonable that guayulins may possess significant biological properties (e.g., antibacterial and anticancer activities), in close analogy with those shown by sesquiterpene lactones contained in many other species of Parthenum genus. As a matter of fact, guayulins A and B play an important role in the synthesis of antineoplastics used in breast cancer treatment. In this contribution we propose an original and validated RP-HPLC approach to the simultaneous quantification of guayulins A, B, C and D. The procedure of resin extraction from Guayule biomass has been optimized in terms of both extraction method and solvent. RP-HPLC separation has been accomplished by an Ascentis ® C18 column under isocratic elution with a 80:20 (v:v) acetonitrile:water mixture. Validation was carried out in terms of limits of detection and quantification, linearity, precision, and trueness. Finally, the method was tested with a number of fresh and seasoned samples of spontaneous Guayule shrub from Mexico.

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Section: Analysis Of the Resin Extractssupporting

confidence: 88%

Section: Assessment Of the Chromatographic Methodsmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Assessment, Validation and Application to Real Samples of an RP-HPLC Method for the Determination of Guayulins A, B, C and D in Guayule Shrub

et al. 2018

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Effects of environment and composition on degradation of guayule rubber

Schloman

McIntyre

Hilton

et al. 1996

J. Appl. Polym. Sci.

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SYNOPSISBales of antioxidant-stabilized guayule rubber underwent significant losses in bulk viscosity when stored under ambient conditions at an Arizona processing facility. Previous work implicated the unsaturated fatty acid esters present in entrained resin as promoters of such degradation. Aging studies as functions of storage temperature and unsaturated acid ester content were carried out on both hulk rubber and rubber-resin solution (miscella) for cultivar AZ-101. The rate of thermooxidative degradation, determined as a function of Mooney viscosity, was increased by the addition of unsaturated ester. Anaerobic degradation was not affected in this way. The activation energy of chain thermolysis was found to be 116 f 6 kJ/mol (28 k 1 kcal/mol). A t temperatures above 60°C, chain recombination successfully competed with chain scission in lower viscosity rubber. The rate of thermooxidative degradation was substantially higher in a typical process miscella. A hindered amine antioxidant significantly reduces chain scission under these conditions. 0 1996 John Wiley & Sons. Inc.

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Rubber, Guayule

Cornish

Schloman

2004

Encyclopedia of Polymer Science and Technology

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Guayule ( Parthenium argentatum ) is a rubber‐producing woody shrub native to the Chihuahuan Desert of northern Mexico and Texas. Guayule produces linear, high molecular weight natural rubber that can have physical properties and applications equivalent to those of Hevea ( Hevea brasiliensis ) rubber. Guayule rubber can be extracted as a solid bulk polymer or as a latex. Guayule also is one of very few rubber‐producing plants to have ever been used commercially for rubber production. Although guayule rubber was commercially produced in the early part of the last century, more recent efforts to reinstate production have not led to commercial success because the production costs of bulk rubber were too high to permit direct competition with Hevea rubber. Guayule commercialization has been revitalized in recent years by use of the plant to produce low protein hypoallergenic latex, a higher value rubber raw material.

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Guayule byproduct evaluation: extract characterization

Cited by 75 publications

References 9 publications

Assessment, Validation and Application to Real Samples of an RP-HPLC Method for the Determination of Guayulins A, B, C and D in Guayule Shrub

Assessment, Validation and Application to Real Samples of an RP-HPLC Method for the Determination of Guayulins A, B, C and D in Guayule Shrub

Effects of environment and composition on degradation of guayule rubber

Rubber, Guayule

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