Thymol as Starting Material for the Development of a Biobased Material with Enhanced Antimicrobial Activity: Synthesis, Characterization, and Potential Application

Abstract

A biobased material, polythymol (PTF), was prepared using thymol, a monoterpene obtained from the essential oil of Thymus vulgaris (Lamiaceae), as a starting material with the aim of enhancing the antimicrobial properties of this natural product. Initially, different processes were performed in order to optimize the reaction conditions to obtain a macromolecule with a high purity and yield. PTF was characterized using different techniques, such as NMR, infrared, UV-Vis, and thermogravimetric analyses. The antimicrobial activity of both PTF and thymol was evaluated against different microorganisms, including S. aureus, E. coli, P. aeruginosa, and C. albicans. The obtained MIC values showed a higher potential for PTF than the monomer thymol—for example, against S. aureus (500 and 31.5 µg·mL−1 for thymol and PTF, respectively). Therefore, the obtained results show that the polymerization of thymol afforded more active biomaterial than the starting monomeric antimicrobial compound (thymol), suggesting that PTF is an important biomaterial.

Thymol, a Monoterpenoid within Polymeric Iodophor Formulations and Their Antimicrobial Activities

“…Thyme is a globally well-known medicinal plant utilized historically against microbial infections [42,[57][58][59][60][61][62][63][64][65][66][67][68][69][70]. Thyme extracts contain the antimicrobial secondary metabolites Thymol and carvacrol [3,5,[9][10][11][12][13][14]42,[60][61][62][63][64][65][66][67][69][70][71]. Thymol, a monoterpenoid with outstanding antimicrobial properties, appears in an increasing number of investigations in combination with other essential oils, plant extracts, nanoparticles, and chitosan [70][71][72][73][74][75][76][77][78][79][80][81][82]…”

“…Thyme extracts contain the antimicrobial secondary metabolites Thymol and carvacrol [3,5,[9][10][11][12][13][14]42,[60][61][62][63][64][65][66][67][69][70][71]. Thymol, a monoterpenoid with outstanding antimicrobial properties, appears in an increasing number of investigations in combination with other essential oils, plant extracts, nanoparticles, and chitosan [70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88]. Thymol is a strong antimicrobial agent, which can easily enter cell membranes due to its small size and structural properties [68,71,73,79,81,82,86].…”

“…Thymol, a monoterpenoid with outstanding antimicrobial properties, appears in an increasing number of investigations in combination with other essential oils, plant extracts, nanoparticles, and chitosan [70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88]. Thymol is a strong antimicrobial agent, which can easily enter cell membranes due to its small size and structural properties [68,71,73,79,81,82,86]. Thymol can enter like carvacrol through the microbial cell membranes [82,86].…”

“…Thymol can enter like carvacrol through the microbial cell membranes [82,86]. Thymol can pass through the pores in the Gram-negative bacterial cell membrane [68,71,73,79,81,82,86]. The polar hydroxyl group interacts through hydrogen bonding with the polar cell membrane components and compromises cell functions [68,71,73,79,81,82,86].…”

“…Thymol can pass through the pores in the Gram-negative bacterial cell membrane [68,71,73,79,81,82,86]. The polar hydroxyl group interacts through hydrogen bonding with the polar cell membrane components and compromises cell functions [68,71,73,79,81,82,86]. Its nonpolar aromatic ring engages with lipid bilayers and changes their fluidity and flexibility [82,86].…”