Green Synthesized Polymeric Iodophors with Thyme as Antimicrobial Agents

Abstract

Antimicrobial resistance (AMR) is a growing concern for the future of mankind. Common antibiotics fail in the treatment of microbial infections at an alarming rate. Morbidity and mortality rates increase, especially among immune-compromised populations. Medicinal plants and their essential oils, as well as iodine could be potential solutions against resistant pathogens. These natural antimicrobials abate microbial proliferation, especially in synergistic combinations. We performed a simple, one-pot synthesis to prepare our formulation with polyvinylpyrrolidone (PVP)-complexed iodine (I2), Thymus Vulgaris L. (Thyme), and Aloe Barbadensis Miller (AV). SEM/EDS, UV-vis, Raman, FTIR, and XRD analyses verified the purity, composition, and morphology of AV-PVP-Thyme-I2. We investigated the inhibitory action of the bio-formulation AV-PVP-Thyme-I2 against 10 selected reference pathogens on impregnated sterile discs, surgical sutures, cotton gauze bandages, surgical face masks, and KN95 masks. The antimicrobial properties of AV-PVP-Thyme-I2 were studied by disc diffusion methods and compared with those of the antibiotics gentamycin and nystatin. The results confirm AV-PVP-Thyme-I2 as a strong antifungal and antibacterial agent against the majority of the tested microorganisms with excellent results on cotton bandages and face masks. After storing AV-PVP-Thyme-I2 for 18 months, the inhibitory action was augmented compared to the fresh formulation. Consequently, we suggest AV-PVP-Thyme-I2 as an antimicrobial agent against wound infections and a spray-on contact killing agent.

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

“…Within various molecular structures, iodine forms diverse moieties, including molecular iodine, iodide ions, triiodide, and higher polyiodide anions like pentaiodides and heptaiodides [28][29][30][31][32][33][34][35][36][37][38][39][40][41]. Our previous investigations dealt with some of those polyiodide units within different molecular environments like 12-crown-4 or PVP, which impact their stability and antimicrobial activities [42][43][44][45][46][47][48][49][50][51][52][53]. Although triiodides [I 3 − ] are deemed the most stable form of polyiodides, they display several different structural subtypes with different stability [25,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]45,46,…”

“…Our previous investigations dealt with some of those polyiodide units within different molecular environments like 12-crown-4 or PVP, which impact their stability and antimicrobial activities [42][43][44][45][46][47][48][49][50][51][52][53]. Although triiodides [I 3 − ] are deemed the most stable form of polyiodides, they display several different structural subtypes with different stability [25,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]45,46,49,50]. Triiodides can manifest as inherently stable, symmetrical, linear "smart" units [I-I-I − ] and less stable, nonlinear [I-I .…”

“….. I − ] configurations, contingent upon their immediate molecular environment [25,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]45,46,49,50]. The moieties, which are marked by uncontrolled iodine release, therefore diminishing long-term stability and treatment efficacy, are the nonlinear [I-I .…”

“…I − ] configurations [25,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]45,46,49,50]. Control over iodine release mechanisms can be achieved by promoting the formation of "smart", linear, and symmetrical triiodides [I-I-I − ] through precise molecular surroundings that stabilize them within compatible complexing agents [25,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]45,46,49,50]. One of the best complexing agents appears to be polyvinylpyrrolidone (PVP).…”

“…Its applications range from oral care to wound treatment and surgical procedures [16][17][18][19][20][21][22][23][24][25][26][27]. Different combinations of PVP-I 2 with medicinal plants have been garnering interest for some time [16][17][18][19][20][21][22][23][24][25][26][27]42,43,[45][46][47]. Rahma et al studied PVP-curcumin combinations with good antimicrobial activities [47].…”