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An antimicrobial preparation consisting of a monolaurin dispersion also containing 2 per cent hydrogen peroxide is described. In laboratory experiments the antimicrobial effects of this dispersion has been tested against a variety of bacteria, a virus and a strain of oral yeast. For the tested bacteria and the virus the results showed more favourable effects with the described dispersion than with two simultaneously tested standard antimicrobial preparations. The results of performed preliminary clinical experiments Show effectiveness by the dispersion both as a prophylactic agent after oral surgery and as a treatment for some common acute and chronic oral mucosal pathologic conditions.

A simple and convenient method for the simultaneous determination of mono-di- and triacylglycerols has been developed. Acylglycerols from monolaurin to tristearin were separated by reversed-phase high-performance liquid chromatography and detected with the acylglycerol-selective post-column reaction detector. The detector indicated the molar response of all acylglycerols from monolaurin to tristearin. It can, for example, detect 0.07 nmol of 1-monopalmitin and give a linear calibration graph between 0.2 and 121 nmol of 1-monopalmitin. Furthermore, acylglycerols in commercial products could be selectively detected and quantitated without any pretreatment. Therefore, the proposed method should offer a versatile method for the analysis of acylglycerols in natural and commercial products.

The author reviews his research, since 1966, for the ideal germicide. The relationship between structure of fatty acids, their corresponding esters, and antimicrobial activity is presented. Saturated fatty acids have their highest activity when the chain length is twelve carbons (C12) long; monounsaturated fatty acids reach their peak with palmitoleic acid (C16∶1); the most active polyunsaturated fatty acid is linoleic.Trans isomers are not active against microorganisms. The esterification of fatty acids to monohydric alcohols leads to inactive derivatives, whereas esterification to polyhydric alcohols increases biological activity. Examples of glycerol and sucrose esters are reviewed. In general, the lauroyl derivatives are the most active. A few examples of esters as active pharmacological agents against organisms causing bovine mastitis are presented as well as the use of monolaurin (Lauricidin®) as cosmetic and food preservatives. The safety and efficacy of fatty acid esters as potential germicides offer new and expanded roles for oleochemicals.

The effect of fatty acids, monoglycerides, diglycerides and triglycerides (present or able to be generated in human milk by lipase activity) on the growth of anaerobic Bifidobacterium bifidum types a and b, Bifidobacterium infantis sp. infantis types a and b, and facultative Escherichia coli and Salmonella typhimurium were determined turbidimetrically. The fatty acids and monoglycerides tested inhibited the growth of the Bifidobacteria while the gram-negative E. coli and S. typhimurium proved more resistant. Triglycerides were not inhibitory to the bacteria tested, with some actually enhancing growth. Monolaurin and 2-monopalmitin proved to be the most potent inhibitors of Bjfidobacteria growth in the concentration ranges used.

Now that energy has become a world problem, cheap, effective chemical preservation is critical. This discussion forwards a new concept in food preservation. The concept is based on a 'systems' approach, using three common foodstuffs: monolaurin, food-grade phenolics and chelator, three multifunctional food materials, whose history as potential preservatives is reviewed. Although monolaurin (Lauricidin) is a Generally Recognized As Safe chemical, its use as part of a 'preservative system' is new. Comparisons of its germicidal activity by investigators have shown it to be more effective than proprionates, benzoates and even sorbic acid. The common antioxidants, tert-butylhydroxytoluene (BHT) or tert-butylhydroxyanisole (BHA) have been shown since 1967 to affect a number of different microorganisms, including viruses. The chelator ethylenediamineacetate (EDT A) has weak biocidal activity on its own but can potentiate the effect of the first two biocidal agents, particularly against gram-negative bacteria. The three common food chemicals therefore become part of a 'preservative system'. The amount and ratio of one to the other is determined by the specific need for microbiological protection.

Compared to rats inoculated with Streptococcus mutans , non-inoculated rats did not have any buccal/lingual caries and S. mutans in the oral cavity. However, sulca

Nisin, sorbic acid and two proprietary monolaurin products, Lauricidin R and Lauribic II, were studied. Determinations were made of their abilities to prevent Bacillus licheniformis growth in a model product of the cooked luncheon meat type. This product was made from a 3 : 1 mixture of lean beef and beef fat and contained 2.5% salt, 0.3% sodium tripolyphosphate and 200 ppm sodium nitrite. Various concentrations of the test preservatives were added to batches of the raw meat emulsion inoculated with 2 × 104 B. licheniformis spores g−1 before addition of various concentrations of the test preservatives. Emulsions were cooked to a pasteurization value of 36 (reference temperature 70°C), chilled overnight and then stored at 25°C. The minimum concentrations of the test preservatives necessary to prevent product spoilage occurring within 10 days during abusive storage were: nisin 500 international units g−1, sorbic acid 0.125%, Lauricidin 0.5% and Lauribic 0.25%. These concentrations were also effective in controlling the growth of the natural enterococcus spoilage microflora of this mildly cooked product.

The antimicrobial effects of monolaurin and sorbic acid were compared in laboratory media, cottage cheese and a pork homogenate. Sorbic acid (250–1000 ppm) was more effective than monolaurin (250–1000 ppm) in inhibiting the growth of Staphylococcus aureus S-6 and Salmonella enteritidis 13076 in pH 5.2 trypticase soy broth. Monolaurin was more effective than sorbic acid against the growth of S. typhimurium 13311 under similar conditions. No synergistic effects were observed when combinations of monolaurin and sorbic acid were tested. In the cottage cheese study, 800 ppm sorbic acid effectively inhibited the growth of coliforms and yeasts and molds, but only slightly inhibited the growth of psychrotrophs. Monolaurin at 800 ppm was ineffective in controlling the growth of any of the microorganisms tested. The use of 3000 ppm monolaurin in a pork homogenate had no effect on the outgrowth and gas formation by Clostridium sporogenes PA3679, whereas 3000 ppm sorbic acid delayed outgrowth and gas formation. Combinations of monolalurin and sorbic acid indicated that sorbic acid was the active anticlostridial agent.

When cells of Salmonella typhimurium or other Gram-negative bacteria were suspended in nutrient broth and frozen with certain chemical agents in concentrations to which the unfrozen cells are not sensitive, their viability significantly decreased. Of the various chemical agents tested, laurate and the derivatives [e.g. sodium laurate, sodium lauryl sulfate, monolaurin, polyoxyethylene sorbitan monolaurate (Tween 20), or Sorbitan monolaurate (Span 20)] showed the highest activities in reducing viability. These chemicals were not effective when they were added after thawing. Slow freezing (3°C/min in the cooling rate) and storage at -20°C for 24 hr with 0.2 mM laurate reduced the population of bacteria in nutrient broth to less than five orders. Fast freezing in liquid nitrogen (100 °/min in the cooling rate), slow freezing in the presence of 10% dimethyl sulfoxide or 10 mM Mg++ failed to reduce the viability effectively. Freezing with laurate was also found to be lethal against Gram-positive bacteria.

Dodecylglycerol has a minimum inhibitory concentration of 4 micrograms/ml compared to 9 micrograms/ml for monolaurin (dodecanoylglycerol) with Streptococcus faecium ATCC 9790 as the test organism. The greater potency of dodecylglycerol can be correlated to its greater retention by the cell. Gram-positive bacteria were more susceptible than Gram-negative bacteria to dodecylglycerol. The antibacterial action of dodecylglycerol is not through the physical dissolution of cell walls, but rather as an enzymatic effector. The autolysin activity of whole cells of S. faecium was greatly stimulated by dodecylglycerol. The stimulation of autolytic activity and inhibition of growth respond in parallel to different concentrations of dodecylglycerol, to dodecylglycerol versus some poorer effector such as monolaurin or a glycerol alkyl ether with a longer or shorter fatty alkyl side chain than dodecanol, and to the antagonistic effects of diphosphatidlyglycerol. This close relationship implies that the stimulation of autolysin activity could be a primary, but not necessarily the only, mechanism by which dodecylglycerol and related compounds exert their antibacterial activity. However, the autolysin activity is not stimulated by a direct interaction between the enzyme and dodecylglycerol. A non-wall entity, such as a proteinase, has been implicated as an intermediary (Ved, H. S., Gustow, E., and Pieringer, R. A. (1984) J. Biol. Chem. 259, 8122-8124).

A sterile agar-meat was acidified with lactic acid and seeded with Staphylococcus aureus. Monolaurin (Lauricidin®), which is a GRAS emulsifier, caused both static and cidal effects on S. aureus 196E. When compared to potassium sorbate, Lauricidin® was slightly more active. The combination of sorbic acid and Lauricidin® (Lauribic™) gave a greater inhibitory effect than either of the substances alone. Inhibitory effects were greater on “anaerobic” than “aerobic” growth. These results indicate that monoglyceride emulsifiers like Lauricidin® alone or in combinations with other preservatives can be used in foods to create environments which are hostile to microorganisms.

The effect of hydrolysis on the surface tension of aqueous solution of 1-monolaurin was studied. The concentrations of 1-monolaurin, lauric acid, and glycerol were calculated according to the kinetic equation reported in the previous paper, taking the method of the preparation of 1-monolaurin solutions into account. The relation between the surface tension and the composition of solutions was obtained at various total concentrations. It was found that 1-monolaurin is more surface-active than lauric acid. From the equilibrium values of the surface tension of partially hydrolyzed 1-monolaurin solution, it was concluded that the adsorption equilibrium of surface phase was established faster than the chemical equilibrium in the surface phase.

Antimicrobial activity of fatty acids and their glycerol and sugar esters against a film-forming yeast isolated from raw soy sauce was determined in diluted soy sauce. In a series of fatty acids (alkyl chain length of 7, 9, 11 and 13) and their monglycerides, capric acid and monolaurin had the highest inhibitory activity. Two selected sugar esters (sucrose monocaprate and sucrose monolaurate) could not completely inhibit the growth of test organism throughout 3 weeks.

A kinetic study was performed on the combined effect of monolaurin and heat on the death of Escherichia coli. The following results were obtained: (1) Monolaurin was about eleven times more active than that of sodium laurate; (2) Temperature enhanced the effect of monolaurin. True enthalpyentropy compensation effect was shown in this death reaction. The value of 341.9°K was obtained from the formula of ΔH*= Tc·ΔS*+ b and 331.5°K from Arrhenius plots as a compensation temperature; (3) The apparent minimum enhancing concentration of monolaurin ranged from 0.0056 mM to 0.013 mM, varying with the heating temperature. It may be concluded from the results of this study that the enhancing effect of monolaurin on the thermal death of E. coli corresponds to that of the amphoteric surfactant type (S type) agent defined in our previous report.

Four different lipolytic preparations have been isolated from rat skeletal muscle. Two of these, provisionally designated monopalmitin lipase (MPL) and monomyristin lipase (MML), are associated with insoluble cellular particulate fractions. The other two enzymes, provisionally designated tricaproin lipase (TCL) and monolaurin lipase (MLL), are found in the high-speed supernatant fraction. Taken as a group, these enzymes are capable of hydrolyzing short-chain triglycerides (acyl moieties of C(3) to C(8)) and monoglycerides of lauric, myristic, palmitic, stearic, and oleic acids. All of these enzymes have a serine residue at or near the catalytic site as they are strongly inhibited by diisopropyl fluorophosphate. The two particulate preparations contain a sulfhydryl group and are sensitive to p-chloromercuribenzoate and N-ethylmaleimide, while the soluble preparations are not. The MLL, MML, and MPL preparations all have alkaline pH optima, while the TCL preparation has an acidic optimum. Buffer type is important: some buffer compounds completely inhibited one or more preparations. Of the soluble enzymes, MLL withstood heating to 60 degrees C, while TCL is completely inactivated at this temperature. Of the particulate preparations, only MML was stable to lyophilization. It is concluded that there are at least four lipolytic enzymes in rat skeletal muscle. The possible significance of the presence of these enzymes in muscle is discussed.

When concentrated monoglycerides (such as distilled products) are heated to about their melting point with water, a gel is formed. The exact temperature of gelation is dependent upon molecular weight of the fatty acid (monolaurin does not gel, but monopalmitin does) and upon the the purity of the monoglyceride.

Dissolution rate of the monolayer of 1-monolaurin at constant area was obtained by measuring the decrease of surface pressure. Surface pressure of a monolayer, which had been compressed rapidly and held at a constant area, decreased linearly with the square root of elapsed time. Surface pressure-area curve of the spread monolayer of 1-monolaurin was obtained from the initial pressure obtained by the extrapolation to time zero. It was found that a monolayer of 1- monolaurin was in state a of liquid expanded film. Surface concen-tration corresponding to each surface pressure was calculated from the state equation of liquid expanded film of Jura and Harkins. Logarithm of surface concentration varied linearly with the square root of elapsed time. Adsorption isotherm was calculated by thetheory of Ter Minassian- Saraga for the dissolution rate of a monolayer.It has been concluded that the spread monolayer of 1- monolaurin isequilibrated immedi- ately with the sublayer and then 1- monolaurin dissolved in the sublayer is transfered to bulk liquid by diffusion.

さきにヤシ油について行った35±0.1℃の低温におけるトイッチェル法油脂分解に関する研究で,モノグリセリド→グリセリン反応に最も関連ある部分は水層であろう(A)と推定した。条件は異なるがAにさらに実験的根拠を与えるためにこの研究を行った。α-モノラウリン(B)の油層の厚さ0.7～6.9mmにおいては油層の厚さ,あるいは界面面積が異なっても,65±0.1℃でのBの加水分解率はほとんど変動しない。通常の油脂を加水分解する力のないN/2あるいは1N硫酸でもBを加水分解し,油層でこん跡の硫酸を検出する。1%テトラブチルナフタリン・スルホン酸水溶液はBを可溶化する。これらの実験等から,トイッチェル法によるBの65±0.1℃での加水分解反応は界面にほとんど関係がなく,水層および油層で反応が行われること,Bがヤシ油に少量含まれるときは主として水層でBの加水分解反応が行われること,および化学反応が律速段階であることを立証した。

The structural relationships of 30 straight-chain fatty acids and derivatives and their bactericidal properties were studied with 8 gram-negative and 12 grampositive organisms. Chain length, unsaturation ( cis, trans ), and functional group were all variables considered in this study. Our data indicate that C 12 (lauric acid) is the most inhibitory saturated fatty acid against gram-positive organisms. Monoenoic acid (C 18:1 ) was more inhibitory than saturated fatty acid, but was less active than dienoic derivatives (C 18:2 ). Other unsaturated compounds were less active than C 18:2 . Alcohols and glyceryl esters were active only against gram-positive organisms. In general, esterification of the carboxyl group led to a compound which was less active; monoglycerides were the sole exception. Amine derivatives, contrary to results with fatty acids, esters, and amides, showed activity against both gram-positive and gram-negative organisms.

Mixtures of glycerides prepared by glycerolysis or direct esterification were fractionated in homogeneous phase by urea adduct method. Urea was added in each fractional stage. The weight of urea and solvent to be added, the solubility of urea in solvents and a forming tendency of urea adducts were examined. The experimental results were summarized as follows : 1) It is better for monolaurin and dilaurin to dissolve in methanol and also for trilaurin in methanol-benzene.2) The ratios of urea and the solvent, 5 : 50 and 5 : 100 by weight, were the best for monolaurin and dilaurin respectively when 5g of the sample was used.3) In case urea was added to the sample dissolved in methanol-benzene, a great deal of trilaurin could not form urea adduct, but crystallized more rapidly than 1, 3-dilaurin adduct.4) In the above experimental conditions, pure 1-monolaurin, 1, 3-dilaurin and trilaurin were isolated.5) On the tendency which glycerides are fractionated, the following results were obtained.Trilaurin>1.3-dilaurin >1.2-dilaurin>1-monolaurin> 2-monolaurin.

A simple, convenient method for the simultaneous determination of the homologous distribution and ratio of positional isomers of monoglycerides in commercial products has been developed. Monoglycerides were analyzed with reversed phase HPLC using the glyceride-selective post-column reactor detector (GS-PCRD). The GS-PCRD indicated molar responsibility to all monoglycerides up to monostearin. It can, for example, detect 0.07 nmol of 1-monolaurin and give a linear working curve between 0.18–80.3 nmol of 1-monolaurin. Furthermore, monoglycerides in commercial margarines could be selectively detected and quantitatively determined without any pretreatment. Therefore, the proposed method should be applicable to the analysis of monoglycerides in various commercial products.

Melting dilations have been determined for the even-numbered, saturatedn-fatty acids in the series lauric through stearic, and some of their glyceryl esters. These data have been correlated with data obtained previously to determine the relationship between melting dilation and the effective chain length of these compounds.

Coadministration of trilaurin or monolaurin with sodium cefoxitin increased its absorption from the small intestine of the rat. Its absorption from the rectum was effected to a lesser extent except when lipase was present. Lipase, a natural constituent of the small intestine fluid, may therefore be essential for the adjuvant action of trilaurin on cefoxitin absorption across the intestinal membrane. Among the triglycerides used, trilaurin and tricaprin were the most effective enhancers of cefoxitin absorption. Both the rate of degradation of triglyceride to its fatty acid component and subsequently the rate of fatty acid absorption were factors influencing the enhancing action. Maintenance of fatty acid concentration at the small intestinal absorption site was shown to be necessary to obtain a cefoxitin bioavailability of up to 70%.

Monolaurin alone and monolaurin with tert-butylhydroxyanisole (BHA), methylparaben, or sorbic acid were tested for in vitro virucidal activity against 14 human RNA and DNA enveloped viruses in cell culture. At concentrations of 1% additive in the reaction mixture for 1 h at 23°C, all viruses were reduced in infectivity by >99.9%. Monolaurin with BHA was the most effective virucidal agent in that it removed all measurable infectivity from all of the viruses tested. The compounds acted similarly on all the viruses and reduced infectivity by disintegrating the virus envelope.

The effects of fatty acids and their glycerol and sucrose esters, potassium sorbate, and sodium benzoate on growth of Vibrio parahaemolyticus in laboratory media at pH 6.7 were evaluated. The minimum concentrations at which inhibition by esters of glycerol could be detected were lowest for monolaurin (5 microgram/ml) and monocaprin (40 microgram/ml); these concentrations were lower than those observed for inhibition by lauric and capric acids, respectively. Inhibitory action of sucrose caprylate was detected at 40 microgram/ml, whereas sucrose caprate was effective at 100 microgram/ml; sucrose esters of lauric, myristic, and palmitic acids were ineffective at 100 microgram/ml. Potassium sorbate and sodium benzoate inhibited growth at concentrations as low as 30 and 300 microgram/ml, respectively, and enhanced the rate of thermal inactivation of V. parahaemolyticus at slightly higher concentrations. Fatty acid esters of glycerol and sucrose offer potential as perservatives for slightly acid or alkaline low-fat foods which do not lend themselves to the full antimicrobial action of traditional food preservatives such as potassium sorbate and sodium benzoate.

Introduction Two materials, monolaurin (at two concentrations) and an unidentified species of the genus Streptomyces, were tested along with borax for ability to protect freshly cut stump surfaces of western hemlock (Tsuga heterophylla (Raf.) Sarg.) from colonization by Fomes annosus. Protectants were significantly (P

Weanling rats were given high-sucrose cariogenic diets containing 2 per cent lauric acid, linoleic acid, nonanoic acid or monolaurin. Plaque accumulation was determined on the incisors of half the animals during only the last 3 days of the study and on the remaining animals at the conclusion of a 21-day test period when both sulcal and smooth-surface caries were assessed. No significant differences between the test groups in food consumption were observed nor were there any differences in body weight gain. The least amount of plaque was observed in the animals given monolaurin; the other fatty acids exerted no significant effect upon plaque accumulation. The smooth-surface caries data indicated that the least number of lesions occurred in the animals on the diet containing monolaurin. Nonanoic acid was significantly more effective in limiting sulcal caries than any of the other fatty acids studied. Thus both monolaurin and nonanoic acid have significant cariostatic activity in the rat.

A quantitative method is described for the rapid gas-liquid chromatographic analysis of monoglycerides of long chain fatty acids as their trimethylsilyl (TMS) ether derivatives. The TMS derivatives are formed rapidly and quantitatively at room temp without isomerization. The TMS derivatives of 1- and 2-monoglycerides may be separated on polyester columns, which can also be used for the analysis of methyl esters. A mixture of the 1- and 2-isomers of monopalmitin and monoolein was quantitatively analyzed. A mixture of monocaprin, monolaurin, monomyristin, monopalmitin and monosterin was also analyzed. A mixture of 1-monostearin, 1-monoolein and 1-monolinolein was also resolved. The analyses were carried out on packed and large bore capillary columns of diethylene glycol succinate polyester (DEGS) and Apiezon L. Capillary columns that required the use of a splitter were nonquantitative, resulting from what appeared to be fractionation at the splitter. Acid conditions, including those provoked by the use of phosphoric acid stabilized polyesters, cleaved the TMS derivatives to yield the original hydroxy compound.

The present investigation has revealed the presence of two monoglyceride hydrolyzing enzymes in rat adipose tissue, tentatively designated as monoolein lipase and monolaurin lipase. These two enzymes can be differentiated on the basis of column chromatographic behavior, pH optimum, substrate preference, inhibition characteristics and heat sensitivity. The mobility of monolaurin lipase on Sephadex G-200 and gel electrophoresis is similar to that of a previously reported tributyrinase enzyme but can be differentiated from it on the basis of its inability to hydrolyze tributyrin and its relative insensitivity to F− inhibition.

Monoglyceride-H2O systems in the range above about 5% H2O exhibit a varied phase behavior with a number of mesomorphic states reminiscent of those found for soap-H2O systems. There are fluid neat, stiff and “short” viscous isotropic, and plastic or stringy middle states. In the case of saturated monoglycerides, neat states prevail at low molecular weight as with monolaurin, but viscous isotropic and finally middle states appear at higher chain length as with monoarchidin and monobehenin. The phase diagrams for systems of unsaturated compounds resemble those for systems of saturated compounds, with corresponding phase regions occurring at lower temperatures. The monoelaidin-H2O system closely resembles a shifted monostearin-H2O system, neither system showing middle. Middle phase appears in a small island for monoolein and monolinolein near 90C and 20% water. Water dissolves negligible amounts of monoglycerides so that phases which are nearly 100% H2O exist for substantially all systems and conditions when H2O content is 60% or more.

The characteristics of a fluoride-sensitive soluble tributyrinase isolated from rat adipose tissue were investigated. The purity of the preparation was demonstrated by disc gel electrophoresis. This enzyme was shown to be similar to tributyrinase in rat heart, lung, liver and kidney. It has a pH optimum of 8.5 in Tris-phosphate buffer. Furthermore, the enzyme is inhibited by DFP, but is insensitive to eserine, Mg2+ and Ca2+. The fluoride-sensitive tributyrinase shows a specificity for short chain glycerol esters (mono-, di-, and tributyrin) and little activity on long chain glycerol esters (monolaurin, monoolein, triolein and tripalmitin).

In this report the results of further investigations on the characteristics of a previously reported monoglyceride hydrolyzing enzyme in adipose tissue, designated as monoolein lipase, are presented. The utilization of discontinuous sucrose gradient centrifugation has resulted in a greatly increased specific activity of monoolein lipase and has allowed separation of this enzyme from monolaurin lipase and tributyrinase. Monoolein lipase shows a high specificity for monoglyceride substrates with no hydrolytic activity against the corresponding triglycerides or methyl esters. The synthesis and assay of various monoglyceride substrates has indicated that those substrates containing unsaturation in the fatty acid moiety are more readily hydrolyzed than the corresponding monoglycerides containing saturated fatty acids. Monoolein lipase is higly sensitive to inactivation by p-chloromercuribenzoate (PCMB), and dithiothreitol is capable of reversing and preventing the PCMB inhibition.

Relaxation phenomena in a whey protein isolate (WPI) and monoglycerides (monopalmitin, monolaurin, and monoolein) mixed films at the air−water interface were studied using surface film balance and Brewster angle microscopy (BAM). Relaxation in surface area at a constant surface pressure (at 20 mN/m) or at constant area at the collapse point have been analyzed according to models for desorption, collapse, and/or organization/reorganization changes. At a constant surface pressure, the organization/reorganization change of WPI molecules in monopalmitin− and monoolein−WPI mixed films is the mechanism that controls the relaxation process. At the collapse point of the mixed film, the relaxation phenomena may be due either to nucleation and growth of critical nuclei of monoglyceride or to a complex mechanism including competition between desorption and monolayer collapse. For WPI−monolaurin mixed films the relaxation phenomena are mainly due to the irreversible loss of monolaurin molecules by desorption into the...

SN-38 is a potent active metabolite of irinotecan that has been considered as an anticancer candidate. However, the clinical development of this compound has been hampered by its poor aqueous solubility and chemical instability. In this study, we developed SN-38-encapsulated cubosomes to resolve these problems. Six α-monoglyceride additives, comprising monocaprylin, monocaprin, monolaurin, monomyristin, monopalmitin, and monostearin, were used to prepare phytantriol (PHYT) cubosomes by probe sonication. The mean particle size, polydispersity index, and zeta potential values of these systems were around 190-230 nm, 0.19-0.25 and -17 to -22 mV, respectively. Small-angle X-ray scattering analyses confirmed that the SN-38-encapsulated cubosomes existed in the Pn̄3m space group both with and without the additives. The monoglyceride additives led to around a two-fold increase in the solubility of SN-38 compared with the PHYT cubosome. The drug entrapment efficiency of PHYT cubosomes with additives was greater than 97%. The results of a stability study at 25°C showed no dramatic changes in the particle size or polydispersity index characteristics, with at least 85% of the SN-38 existing in its active lactone form after 10 d, demonstrating the high stability of the cubosome nanoparticles. Furthermore, approximately 55% of SN-38 was slowly released from the cubosomes with additives over 96 h in vitro under physiological conditions. Taken together, these results show that the SN-38-encapsulated PHYT cubosome particles are promising drug carriers that should be considered for further in vivo experiments, including drug delivery to tumor cells using the enhanced permeability and retention effect.

Doležalkova I., Macalik Z., Butkovicova A., Janis R., Buňkova L. (2012): Monoacylglycerols as fruit juices preservatives. Czech J. Food Sci., 30: 567–572. Limiting or preventing the growth of undesirable microbial flora in food products is one of the main goals of food microbiology. A number of preservation methods have been designed to extend the shelf-life of the food products by reducing the microbial growth while new antimicrobials are still examined. Monoglycerides are naturally occurring compounds with inhibitory activity against various microorganisms. We evaluate the antimicrobial effects of 8 monoglycerides in vitro and in fresh unpasteurised apple juice. Out of all monoglycerides tested, monocaprin (MAG C10:0) and monolaurin (MAG C12:0) showed the best ability to supress or prevent the growth of filamentous fungi in vitro. The addition of these monoglycerides to apple juice resulted in a decrease in total viable counts of bacteria and yeasts. Monocaprin was able to stop completely the growth of bacteria and yeasts at a concentration of 250 μg/ml, and to prevent microbial spoilage of apple juices for at least two weeks.

Development of effective antibacterial agents for the treatment of infections caused by Gram-positive bacteria resistant to existing antibiotics, such as methicillin-resistant Staphylococcus aureus (MRSA), is an area of intensive research. In this work, the antibacterial efficacy of two antimicrobial peptides derived from plectasin, AP114 and AP138, used alone and in combination with monolaurin-lipid nanocapsules (ML-LNCs) was evaluated. Several interesting findings emerged from the present study. First, ML-LNCs and both plectasin derivatives showed potent activity against all 14 tested strains of S. aureus, independent of their resistance phenotype. Both peptides displayed a considerable adsorption (33%-62%) onto ML-LNCs without having an important impact on the particle properties such as size. The combinations of peptide with ML-LNC displayed synergistic effect against S. aureus, as confirmed by two methods: checkerboard and time-kill assays. This synergistic interaction enables a dose reduction and consequently decreases the risk of toxicity and has the potential of minimizing the development of resistance. Together, these results suggest that ML-LNCs loaded with a plectasin derivative may be a very promising drug delivery system for further development as a novel antibacterial agent against S. aureus, including MRSA.

Biofilm provides a bacterial hiding place by forming a physical barrier and causing physiological changes in cells. The elimination of biofilm is the main goal of hygiene. Chemicals that are inhibitory to biofilm formation have been developed for use in food, personal hygiene products, and medical instruments. Monoacylglycerols are recognized as safe and are used in food as emulsifiers. In this study, the inhibitory activity of monoacylglycerols on bacterial biofilm formation was evaluated systematically with four bacterial strains, Aeromonas hydrophila, Streptococcus mutans, Xanthomonas oryzae, and Yersinia enterocolitica. Monoacylglycerols with two specific lengths of fatty acid moiety, monolaurin and monobehenin, were found to have strong inhibitory activity toward bacterial biofilm formation of S. mutans, X. oryzae, and Y. enterocolitica in a strain specific manner. First, this result suggested that biofilm formation was not inhibited by the detergent characteristics of monoacylglycerols. This suggestion was supported by the inhibitory action of monolaurin on biofilm development but not on the initial cell attachment of Y. enterocolitica in flow cytometric observation. Second, it was also suggested that two distinct response mechanisms to monoacylglycerols existed in bacteria. The existence of these two inhibitory response mechanisms was bacterial strain specific. Electronic supplementary material The online version of this article (doi:10.1186/s40064-016-3182-5) contains supplementary material, which is available to authorized users.

International audience; This study highlighted combinations of chemical stresses that could decrease or eliminate Listeria monocytogenes and Pseudomonas spp. surviving in food processing plants. Strains of L. monocytogenes, Pseudomonas fragi, and Pseudomonas fluorescens isolated from processing environments (meat and milk) were grown at 20 degreesC up to the early stationary phase. The strains were then subjected to 30 min of physicochemical treatments. These treatments included individual or combined acid (acetic acid), alkaline (NaOH), osmotic (NaCl), and biocides (fatty acids) challenges. Survival of the strains was studied after individual or combined acid (acetic acid), alkaline (NaOH), osmotic (NaCl), and biocides (monolaurin, lauric acid) challenges. Individual pH shocks had lower efficiencies than those used in combinations with other parameters. The treatment pH 5.4 followed by pH 10.5 had a low efficiency against L. monocytogenes. The opposite combination, pH 10.5 followed by pH 5.4, led to a 3-log reduction of the L. monocytogenes population. Pseudomonas spp. strains were much more sensitive than L. monocytogenes, and population reductions of 5 and 8 log (total destruction), respectively, were observed after the same treatments. As for L. monocytogenes, the combination pH 10.5 followed by pH 5.4 is more deleterious than the opposite. Whatever the bacterial species, the most efficient treatments were combinations of alkaline, osmotic, and biocide shocks. For instance, the combination pH 10.5 and 10% NaCl plus biocides showed reductions of 5 to 8 log for both bacteria. The origins of the observed lethal effects are discussed.

The crystal structure of the β form of α-monolaurin has been determined. The space group is P21, with a=9.2472(3), b=74.310(2), c=4.9523(1)A, β=97.514(3)°, and Z=8. Two types of molecular conformations of monolaurin exist in the crystal.

LauricidinR (monolaurin) and related compounds were tested against 16 fungi belonging to different groups and having different cell wall composition. Lauricidin Plus F (a combination of monolaurin, butylated hydroxy anisole and ethylenediaminetetraacetic acid) was the most effective agent and inhibited the growth of all fungi tested at a concentration of 0.1%. Lauribic (a combination of monolaurin and sorbic acid) also exhibited strong antifungal activity but was less effective than Lauricidin Plus F. In most cases Lauricidin showed antifungal activity at a concentration of 0.5%. Other commercial samples of monolaurin, e.g. Lauricidin 812 (A), Lauricidin 802 (B), and Lauricidin 112 (C), showed higher antifungal activity than Lauricidin. Tests comparing Lauricidin Plus F with sorbic acid, K sorbate and propionic acid, showed that Lauricidin Plus F has higher antifungal activity except when sclerotia of Sclerotium rolfsii were used for inoculation. Lauricidin Plus F was fungistatic and maintained its activity in a semi-synthetic medium for at least 21 days at 26°C.