Future trends for the analysis of guayulins in guayule (Parthenium argentatum Gray) resins

Effect of Seasonal Decrease in Temperature on the Content and Composition of Guayulins in Stems of Guayule (Parthenium argentatum, Gray)

“…Besides, while the stem content of guayulin A was lower than that of other guayulins, particularly guayulin C, the opposite was seen in the leaf, where the content of guayulin A was high and of the same order as that of guayulin C [4]. This is interesting, because the Sesquiterpenes lactones have attracted much scientific attention because of their functional diversity and abundance, and they are important taxonomic markers in the family Asteraceae to which the genus Parthenium belongs [8,9].…”

“…The purpose of the present study was to establish: (1) whether the decline in the content of one or more guayulins in the stems during the autumn is a general behavior in multiple guayule accessions grown under the same conditions; (2) whether the drop in guayulin content has any impact on the resin yield; (3) whether there is any relationship between the potential drop in the guayulin content and the genetic origin of the various accessions; and finally (4), to question what occurs in the leaves and relate it to what happens in the stems.…”

“…The guayulin family of sesquiterpene secondary metabolites comprises four known members, guayulin A–D [ 1 , 2 ], although several other members may exist [ 3 , 4 ]. Guayulin A was first isolated in 1911 and its structure was determined some years later [ 5 , 6 ].…”

“…Guayulin A was first isolated in 1911 and its structure was determined some years later [ 5 , 6 ]. Guayulins consist of an isoprenoid nucleus, which may be partheniol, with a bicyclogermacrene structure (Guayulins A and B), or its derivative compound with an aromadendrene structure (Guayulins C and D) [ 7 ], esterified either by trans -cinnamic acid (Guayulins A and C), or p -anisic acid (Guayulins B and D) [ 3 , 4 ] ( Figure 1 ). Guayulins have been described in high concentration in the resin component of the rubber plant commonly known as guayule ( Parthenium argentatum , Gray), a perennial shrub native to the Chihuauhan desert region of northern Mexico and Texas that does not produce the pseudoguaianolide sesquiterpene lactones found in almost all other species of the genus Parthenium [ 8 ].…”

“…In a previous study developing analytical techniques to determine guayulin content [ 4 ], it was observed that guayulin A content significantly decreased during autumn in two guayule accessions with a high genotypic diversity (triploid 11619 and hybrid CAL-1) [ 16 ], but conversely, the resin content was higher at this stage [ 4 ]. Such guayulin A decrement that has been reported to be seasonally variable [ 17 ], coincided with the activation of natural rubber production [ 18 , 19 , 20 ].…”