title: Structure-activity relationship of a u-type antimicrobial microemulsion system.
abstract: The structure-activity relationship of a U-type antimicrobial microemulsion system containing glycerol monolaurate and ethanol at a 1∶1 mass ratio as oil phase and Tween 20 as surfactant were investigated along a water dilution line at a ratio of 80∶20 mass% surfactant/oil phase, based on a pseudo-ternary phase diagram. The differential scanning calorimetry results showed that in the region of up to 33% water, all water molecules are confined to the hydrophilic core of the reverse micelles, leading to the formation of w/o microemulsion. As the water content increases, the water gains mobility, and transforms into bicontinuous in the region of 33-39% water, and finally the microemulsion become o/w in the region of above 39% water. The microstructure characterization was confirmed by the dynamic light scattering measurements and freeze-fracture transmission electron microscope observation. The antimicrobial activity assay using kinetics of killing analysis demonstrated that the microemulsions in w/o regions exhibited relatively high antimicrobial activity against Escherichia coli and Staphylococcus aureus due to the antimicrobial oil phase as the continuous phase, while the antimicrobial activity started to decrease when the microemulsions entered the bicontinuous region, and decreased rapidly as the water content increased in the o/w region, as a result of the dilution of antimicrobial oil droplets in the aqueous continuous phase.
authors.affiliation: Department of Food Science and Nutrition, Zijingang Campus, Zhejiang University, Hangzhou, China ; Fuli Institute of Food Science, Zijingang Campus, Zhejiang University, Hangzhou, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Maierhaba
authors.initials: M
authors.lastname: Taxipalati
authors.forename: Liyi
authors.initials: L
authors.lastname: Yu
authors.forename: Fei
authors.initials: F
authors.lastname: Que
authors.forename: Fengqin
authors.initials: F
authors.lastname: Feng
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology; D002152:Calorimetry, Differential Scanning; D004655:Emulsions; D004926:Escherichia coli / Q000187:drug effects; D000431:Ethanol / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007848:Laurates / Q000737:chemistry; D008823:Micelles; D050178:Monoglycerides / Q000737:chemistry; D010316:Particle Size; D011136:Polysorbates / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects; D013329:Structure-Activity Relationship; D013696:Temperature; D013816:Thermodynamics
chemical_list: D000890:Anti-Infective Agents; D004655:Emulsions; D007848:Laurates; D008823:Micelles; D050178:Monoglycerides; D011136:Polysorbates; C020777:monolaurin; D000431:Ethanol