Unlocking the Potential of Water-Insoluble Natural Polymers: Isolation, Characterization, and 2D NMR Quantification of cis-1,4-Poly-β-myrcene in Chios Mastic Gum

Abstract

Natural polymers have garnered attention due to their unique properties, i.e., structural versatility, biocompatibility, and modifiability. Recent efforts focus on sustainable raw materials to develop environmentally friendly processes and products that align with global sustainability goals. Among these, Chios mastic gum, derived from the mastic tree (Pistacia lentiscus var. Chia), is notable for its diverse food, pharmaceutical, and cosmetics applications. One of its key components is cis-1,4-poly-β-myrcene, a natural polyterpene polymer, constituting 20-30% of the resin’s composition. Despite its potential, the complex composition of Chios mastic gum poses challenges in extracting, isolating, and quantifying its polymeric content. NMR spectroscopy offers a nondestructive approach and may be instrumental in developing standardized methods for quantifying cis-1,4-poly-β-myrcene in Chios mastic gum. Such methods are vital for understanding the resin’s composition and exploring potential applications, particularly in sustainable materials and biomedical fields. This study addresses these challenges by producing a cis-1,4-poly-β-myrcene sample as a standard in quantification procedures. Centrifugal partition chromatography, a support-free liquid-liquid chromatography technique, was employed to purify the polymeric fraction. The polymer was then characterized through size exclusion chromatography and NMR methods, including DOSY and quantitative HSQC experiments, to facilitate an accurate analysis and open the door to further applications of this natural polymer.