Extraction and Characterization Methods Used to Identify Value-Added Derivatives and Applications of Guayule Resin

Abstract

Guayule (Parthenium argentatum), a perennial shrub native to the United States southwest and Mexico exhibits adaptations to arid regions. Its potential as an alternative source of natural rubber and latex, particularly in the tire manufacturing, pharmaceutical, and food industries [12] has garnered interest. Additionally, guayule resin holds promise for applications in adhesives, pharmaceuticals, and pesticide/insecticide sectors [14]. However, guayule remains economically unviable, requiring exploration into value-added derivatives found in its resin. The resin is rich in terpenoids, alkaloids, phenolics, sterols, and fatty acids [42, 14]therefore suggesting diverse applications. To realize the plant’s potential as a whole, various extraction and characterization methods will be discussed alongside their benefits.Experimentation included vacuum distillation and vacuum fractional distillation to sep- arate residuals, which contain fatty acids, and terpenes. Under vacuum distillation, the temperature was increased to 220-280 ◦C at constant vacuum. Vacuum fraction distillation had two sets of experiments under different parameters: (1) increasing temperature (220-280 ◦C) at constant vacuum and (2) constant temperature (200 ◦C) and pressure starting at -10 inHg and decreasing in increments of -5 inHg until full vacuum was achieved. Fatty acid and terpene identification and quantification were done under GC/MS analysis. GC/MS analysis showed that fatty acids are temperature and resin amount dependent. Furthermore, the most efficient separation of the terpenes occurred under vacuum fractional distillation at increas- ing temperature, constant pressure. Optimization of these methods should be investigated by fine tuning experimental parameters and identifying standards for GC/MS quantification. This will aid in the determination of commercial utility. The ultimate motivation for this review, experimentation, and analysis is to see if a domestic source of guayule rubber and latex can be introduced to the United States.