Associations between bacterial and fungal communities in the human gut microbiota and their implications for nutritional status and body weight.

This study examined the interplay between bacterial and fungal communities in the human gut microbiota, impacting on nutritional status and body weight. Cohorts of 10 participants of healthy weight, 10 overweight, and 10 obese individuals, underwent comprehensive analysis, including dietary, anthropometric, and biochemical evaluations. Microbial composition was studied via gene sequencing of 16S and ITS rDNA regions, revealing bacterial (bacteriota) and fungal (mycobiota) profiles. Bacterial diversity exceeded fungal diversity. Statistically significant differences in bacterial communities were found within healthy-weight, overweight, and obese groups. The Bacillota/Bacteroidota ratio (previously known as the Firmicutes/Bacteroidetes ratio) correlated positively with body mass index. The predominant fungal phyla were Ascomycota and Basidiomycota, with the genera Nakaseomyces, Kazachstania, Kluyveromyces, and Hanseniaspora, inversely correlating with weight gain; while Saccharomyces, Debaryomyces, and Pichia correlated positively with body mass index. Overweight and obese individuals who harbored a higher abundance of Akkermansia muciniphila, demonstrated a favorable lipid and glucose profiles in contrast to those with lower abundance. The overweight group had elevated Candida, positively linked to simple carbohydrate consumption. The study underscores the role of microbial taxa in body mass index and metabolic health. An imbalanced gut bacteriota/mycobiota may contribute to obesity/metabolic disorders, highlighting the significance of investigating both communities.

The Effect of Opuntia ficus Mucilage Pectin and Citrus aurantium Extract Added to a Food Matrix on the Gut Microbiota of Lean Humans and Humans with Obesity.

Experimental studies have provided evidence that physicochemical interactions in the food matrix can modify the biologically beneficial effects of bioactive compounds, including their effect on gut microbiota. This work aimed to evaluate the effect of a food gel matrix with Opuntia ficus cladodes mucilage pectin and Citrus Aurantium extract on the growth of four beneficial gut bacteria obtained from the fecal microbiota of people who are lean or who have obesity after digestion in the upper digestive system. To accomplish this, a base formulation of Opuntia ficus cladodes mucilage with or without C. aurantium extract was submitted to an ex vivo fecal fermentation in an automatic and robotic intestinal system. The changes in the intestinal microbiota were determined by means of plate culture and 16S sequencing, while short-chain fatty acids (SCFA) produced in the colon were determined via gas chromatography. In the presence of the extract in formulation, greater growth of Bifidobacterium spp. (+1.6 Log10 Colonic Forming Unit, UFC) and Lactobacillus spp. (+2 Log10 UFC) in the microbiota of lean people was observed. Only the growth in Salmonella spp. (-1 Log10 UFC) from both microbiota was affected in the presence of the extract, which decreased in the ascending colon. SCFA was mainly produced by the microbiota of people who were lean rather than those who had obesity in the presence of the extract, particularly in the ascending colon. The effect of sour orange extract seems to depend on the origin of the microbiota, whether in people who have obesity (25 mM/L) or are lean (39 mM/L).

Inulin from halophilic archaeon Haloarcula: Production, chemical characterization, biological, and technological properties.

Halophilic archaea are capable of producing fructans, which are fructose-based polysaccharides. However, their biochemical characterization and biological and technological properties have been scarcely studied. The aim of this study was to evaluate the production, chemical characterization, biological and technological properties of a fructan inulin-type biosynthesized by a halophilic archaeon. Fructan extraction was performed through ethanol precipitation and purification by diafiltration. The chemical structure was elucidated using Fourier Transform-Infrared Spectroscopy and Nuclear Magnetic Resonance (NMR). Haloarcula sp. M1 biosynthesizes inulin with an average molecular weight of 8.37 × 106 Da. The maximal production reached 3.9 g of inulin per liter of culture within seven days. The glass transition temperature of inulin was measured at 138.85 °C, and it exhibited an emulsifying index of 36.47 %, which is higher than that of inulin derived from chicory. Inulin from Haloarcula sp. M1 (InuH) demonstrates prebiotic capacity. This study represents the first report on the biological and technological properties of inulin derived from halophilic archaea.

Gum Arabic/Chitosan Coacervates for Encapsulation and Protection of Lacticaseibacillus rhamnosus in Storage and Gastrointestinal Environments.

Probiotics, such as Lacticaseibacillus rhamnosus, are essential to the food industry for their health benefits to the host. The Lcb. rhamnosus strain is susceptible to processing, gastrointestinal, and storage conditions. In this study, Lcb. rhamnosus strains were encapsulated by complex coacervation in a gum arabic/chitosan or gum arabic/trehalose/chitosan and cross-linked with sodium tripolyphosphate. The physicochemical properties (zeta potential, water activity, water content, and hygroscopicity), encapsulation efficiency, and probiotic survival under storage conditions and simulated gastrointestinal fluids were evaluated. The results showed that crosslinking improves the encapsulation efficiency after drying; however, this result was remarkable when trehalose was used as a cryoprotectant. Furthermore, the encapsulation matrix preserved the viability of probiotics during 12 weeks with probiotic counts between 8.7-9.5, 7.5-9.0, and 5.2-7.4 log10 CFU g-1 at -20, 4, and 20 °C, respectively. After 12 days of digestion in an ex vivo simulator, acetic, butyric, propionic, and lactic acid production changed significantly, compared to free probiotic samples. This work shows that encapsulation by complex coacervation can promote the stability of probiotic bacteria in storage conditions and improve the viability of Lcb. rhamnosus HN001 during consumption so that they can exert their beneficial action in the organism.

Identification and Characterization of Probiotic Lactiplantibacillus plantarum BI-59.1 Isolated from tejuino and Its Capacity to Produce Biofilms.

Tejuino is a popular and traditional beverage consumed in north and western of Mexico, due to its biological properties, it is considered a natural source of probiotics. Nevertheless, few studies have been performed on Tejuino microbiota. In this work, the probiotic potential of the tejuino isolated Lactiplantibacillus plantarum BI-59.1 strain was investigated. Its effectiveness was compared with a commercial Lactobacillus spp and identified by 16S rDNA sequence homology. Lactiplantibacillus plantarum BI-59.1 strain showed probiotic properties, i.e., production of antimicrobial compounds (lactic acid and presence of plantaricin A gene), inhibition of entero-pathogens by planktonic cells and metabolites (Salmonella enterica serovar Typhimurium inhibition to HT29-MTX adhesion), biofilm formation, bacterial adhesion (HT29-MTX, 3.96 CFU/cell), and tolerance to stimulated gastrointestinal conditions (tolerance to pH 3 and bile salts). The strain was gamma hemolytic, susceptible to most antibiotics and negative for gelatinase production; thus, the Lactiplantibacillus. plantarum BI-59.1 strain is suitable for its use as a probiotic for nutraceutical or pharmaceutical formulations.

Enzymatic Crosslinked Hydrogels of Gelatin and Poly (Vinyl Alcohol) Loaded with Probiotic Bacteria as Oral Delivery System.

Probiotic bacteria are widely used to prepare pharmaceutical products and functional foods because they promote and sustain health. Nonetheless, probiotic viability is prone to decrease under gastrointestinal conditions. In this investigation, Lactiplantibacillus plantarum spp. CM-CNRG TB98 was entrapped in a gelatin−poly (vinyl alcohol) (Gel−PVA) hydrogel which was prepared by a "green" route using microbial transglutaminase (mTGase), which acts as a crosslinking agent. The hydrogel was fully characterized and its ability to entrap and protect L. plantarum from the lyophilization process and under simulated gastric and intestine conditions was explored. The Gel−PVA hydrogel showed a high probiotic loading efficiency (>90%) and survivability from the lyophilization process (91%) of the total bacteria entrapped. Under gastric conditions, no disintegration of the hydrogel was observed, keeping L. plantarum protected with a survival rate of >94%. While in the intestinal fluid the hydrogel is completely dissolved, helping to release probiotics. A Gel−PVA hydrogel is suitable for a probiotic oral administration system due to its physicochemical properties, lack of cytotoxicity, and the protection it offers L. plantarum under gastric conditions.

Use of Pleurotus ostreatus to Enhance the Oxidative Stability of Pork Patties during Storage and In Vitro Gastrointestinal Digestion.

Lipid and protein oxidation are the major causes of meat quality deterioration. Edible mushrooms have been proposed as a strategy to prevent quality deterioration during cold storage. This study aimed to assess the effects of Pleurotus ostreatus powder (POP) on the oxidative stability of pork patties during cold storage and after in vitro gastrointestinal digestion (ivGD). Pork patties were subjected to four treatments: control (without antioxidant), T1 (2% POP, w/w) and T2 (5% POP, w/w), and T3 as positive control (0.02% BHT, fat basis). POP aqueous, ethanolic, and aqueous ethanol extract were subjected to phytochemical and antioxidant assays. Raw pork patties were subjected to a chemical proximate composition evaluation. At the same time, raw and cooked pork patties were stored at 2 °C for 9 days and subjected to meat quality measurements. Furthermore, the total antioxidant activity of cooked pork patties was determined after ivGD. Results showed that POP ethanol extract showed the highest polysaccharide, phenol, and flavonoid content, as well as antiradical and reducing power properties. POP incorporation into raw and cooked pork patties enhances meat quality traits, including pH, water-holding capacity, cooking-loss weight, texture, color, lipid, and protein oxidation (p < 0.05). Furthermore, incorporating POP into cooked samples increases the phytochemical content and antioxidant activity during ivGD. In conclusion, POP has great potential as a natural antioxidant for meat products.

Anticandidal and Antibiofilm Effect of Synbiotics including Probiotics and Inulin-Type Fructans.

BACKGROUND: There is great interest in the search for new alternatives to antimicrobial drugs, and the use of synbiotics is a promising approach to this problem. This study evaluated the growth inhibition and antibiofilm activity of the short-chain fatty acids produced by Lacticaseibacillus rhamnosus and Pediococcus acidilactici in combination with inulin-type fructans against Candida albicans. METHODS: The growth inhibition of Candida was evaluated using microdilution analysis in 96-well microtiter plates; different concentrations of cell-free supernatants of Lacticaseibacillus rhamnosus and Pediococcus acidilactici were exposed to Candida albicans. The antibiofilm assessment was carried out using the crystal violet staining assay. The short-chain fatty acids were analyzed by gas chromatography. RESULTS: The clinically isolated Candida albicans interacted with supernatants from Lacticaseibacillus rhamnosus and Pediococcus acidilactici and showed significant growth inhibition and antibiofilm formation versus the controls. Lactate and acetic acid were elevated in the supernatants. The results suggest that the supernatants obtained from the synbiotic combinations of Lacticaseibacillus rhamnosus and Pediococcus acidilactici with inulin-type fructans can inhibit the growth and biofilm formation against a clinically isolated Candida albicans strain. CONCLUSIONS: These results suggest that synbiotic formulations could be a promising alternative to antifungal drugs in candidiasis therapy.

Antioxidant Capacity, Vitamin C and Polyphenol Profile Evaluation of a Capsicum chinense By-Product Extract Obtained by Ultrasound Using Eutectic Solvent.

Habanero pepper leaves and stems (by-products) have been traditionally considered waste; however, bioactive compounds such as polyphenols, vitamin C and carotenoids have been identified that can be used for formulation of nutraceuticals or functional foods. Furthermore, the extraction of these bioactive compounds by using environmentally friendly methods and solvents is desirable. Thus, the aim of this study was to assess the antioxidant capacity, total polyphenol content (TPC), the phenolic profile and vitamin C content in extracts obtained from by-products (stems and leaves) of two varieties (Mayapan and Jaguar) of habanero pepper by ultrasound-assisted extraction (UAE) using natural deep eutectic solvents (NADES). The results showed that NADES leads to extracts with significantly higher TPC, higher concentrations of individual polyphenols (gallic acid, protocatechuic acid, chlorogenic acid, cinnamic acid, coumaric acid), vitamin C and, finally, higher antioxidant capacity (9.55 ± 0.02 eq mg Trolox/g DM) than UAE extraction performed with methanol as the solvent. The association of individual polyphenols with NADES was confirmed by principal component analysis (PCA). Overall, NADES is an innovative and promising "green" extraction technique that can be applied successfully for the extraction of phenolic compounds from habanero pepper by-products.

Antimicrobial and Antibiofilm Effect of Inulin-Type Fructans, Used in Synbiotic Combination with Lactobacillus spp. Against Candida albicans.

There is great interest in the search for new alternatives to antimicrobial drugs, and the use of prebiotics and probiotics is a promising approach to this problem. This study aimed to assess the effect of inulin-type fructans, used in synbiotic combinations with Lactobacillus paracasei or Lactobacillus plantarum, on the production of short-chain fatty acids and antimicrobial activity against Candida albicans. The inhibition assay using the L. paracasei and L. plantarum supernatants resulting from the metabolization of inulin-type fructans displayed growth inhibition and antibiofilm formation against C. albicans. Inhibition occurred at concentrations of 12.5, 25, and 50% of the L. paracasei supernatant and at a concentration of 50% of the L. plantarum supernatant. The analysis of short-chain fatty acids by gas chromatography showed that lactic acid was the dominating produced metabolite. However, acetic, propionic, and butyric acids were also detected in supernatants from both probiotics. Therefore, the synbiotic formulation of L. paracasei or L. plantarum in the presence of inulin-type fructans constitutes with anticandidal effect is a possible option to produce antifungal drugs or antimicrobial compounds.

Involvement of the fecal amino acid profile in a clinical and anthropometric study of Mexican patients with insulin resistance and type 2 diabetes mellitus.

The amino acids synthesized by the intestinal microbiota have been correlated with metabolic diseases, such as type 2 diabetes mellitus and insulin resistance; both are high incidence conditions in Mexico. However, the knowledge of the relationship of fecal amino acids with the development of both diseases in the Mexican population is scarce. The clinical study was descriptive; the study was carried out in the Antiguo Civil Hospital of Guadalajara. Samples were taken from a total of 48 participants with insulin resistance, diabetes, and a control group (n = 16 each). Anthropometric and biochemical measures were evaluated. HPLC carried out the quantification of fecal amino acids. A strong correlation between alanine and HOMA-IR (r = 0.5416) was found and between phenylalanine and HOMA-IR (r = 0.4258). Other interesting correlations were between alanine and glucose (r = 0.5854) and isoleucine and glucose (r = 0.5008). The diabetic group and the insulin-resistant group had increased fecal values of valine and isoleucine (branched-chain amino acids), which were positively correlated with the progression of both conditions. Likewise, alanine and phenylalanine can help predict the development of the disease in the Mexican population. Registry number: 037/19.

Preliminary Study on Citrus Oils Antibacterial Activity Measured by Flow Cytometry: A Step-by-Step Development.

Essential oils of Citrus sinensis and Citrus latifolia have shown biological functions as antiseptics, anti-inflammatories, antioxidants, antifungal and antimutagenic, so the evaluation of their antibacterial capacity, by themselves or in combination with standard antibiotics, presents an alternative for infection treatment. Flow cytometry opens the door for the design of faster and more accurate measurement of antibacterial activity. We use a SYTO9/PI staining system on E. coli ATCC 25922 to determine antibacterial activity by counting live and dead cells through flow cytometry. We found that dual staining showed highly variable results due to wavelength overlapping and instead we used fluorochrome individual staining that highly correlated with viable counts. Chloramphenicol and cefotaxime treatments did not present a dose-response behavior, rendered diffuse readings and/or gave filament formation on fluorescence microscopy. Amikacin was a better comparison standard because it presented a dose-response behavior. Essential oils had low antibacterial activity as compared to amikacin, with a maximum of 10% and 20% for C. latifolia and C. sinensis, respectively. Combinations of essential oils with antibiotic resulted in an unforeseen strong inhibition of amikacin activity. Although a low antibacterial activity was found, a series of standardization steps are proposed for antibacterial activity measurement by flow cytometry.

The intestinal mycobiota and its relationship with overweight, obesity and nutritional aspects.

BACKGROUND: The fungal community of the gastrointestinal tract has recently become of interest, and knowledge of its relationship with the development of obesity is scarce. The present study aimed to evaluate the cultivable fungal fraction from the microbiota and to analyze its relationship with obesity. METHODS: Samples were taken from 99 participants with normal weight, overweight and obesity (n = 31, 34 and 34, respectively) and were cultivated in selective medium, and the cultivable yeasts were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Anthropometric and biochemical measures were also evaluated. RESULTS: Eutrophic, overweight and obese groups presented concentrations of 1.6, 2.16 and 2.19 log10  colony-forming units g-1 yeast, respectively. Ascomycota and Basidiomycota were the two identified phyla. At the genus level, Candida spp. showed a relatively high prevalence, and 10 different species were detected: Candida glabrata, Candida orthopsilosis, Candida lambica, Candida kefyr, Candida albicans, Candida krusei, Candida valida, Candida parapsilosis, Candida utilis and Candida humilis (with relative abundances of 71.72%, 5.05%, 21.21%, 6.06%, 29.29%, 27.27%, 8.08%, 16.16%, 1.01% and 2.02%, respectively). CONCLUSIONS: The obese group presented a higher prevalence of Candida albicans. Furthermore, Candida albicans, Candida kefyr and Rhodotorula mucilaginosa showed a high positive correlation with obesity, weight gain and fat mass and showed a negative correlation with high-density lipoprotein and lean mass, parameters related to weight loss.

Classical methods and perspectives for manipulating the human gut microbial ecosystem.

A healthy Human Gut Microbial Ecosystem (HGME) is a necessary condition for maintaining the orderly function of the whole body. Major alterations in the normal gut microbial composition, activity and functionality (dysbiosis) by an environmental or host-related disruptive event, can compromise metabolic, inflammatory, and neurological processes, causing disorders such as obesity, inflammatory bowel disease, colorectal cancer, and depressive episodes. The restore or the maintaining of the homeostatic balance of Gut Microbiota (GM) populations (eubiosis) is possible through diet, the use of probiotics, prebiotics, antibiotics, and even Fecal Microbiota Transplantation (FMT). Although these "classic methods" represent an effective and accepted way to modulate GM, the complexity of HGME requires new approaches to control it in a more appropriate way. Among the most promising emergent strategies for modulating GM are the use of engineered nanomaterials (metallic nanoparticles (NP), polymeric-NP, quantum dots, micelles, dendrimers, and liposomes); phagotherapy (i.e., phages linked with the CRISPR/Cas9 system), and the use of antimicrobial peptides, non-antibiotic drugs, vaccines, and immunoglobulins. Here we review the current state of development, implications, advantages, disadvantages, and perspectives of the different approaches for manipulating HGME.

Physicochemical Composition and Apparent Degree of Polymerization of Fructans in Five Wild Agave Varieties: Potential Industrial Use.

In this study, we characterize fructan extracts from five wild agave varieties at three ages to identify their potential use in the food industry. Physicochemical parameters (solids soluble total and pH), sugar content and fructan distribution profiles by high-performance anion-exchange chromatography (HPAEC) were evaluated. We found that the ages and variety influenced the carbohydrate content and also fructan dispersion. Two- to four-year-old plants exhibited the highest concentrations of free sugars and fructans, with a low apparent degree of polymerization (DPa) of ≤9 monomers, which highlights their potential use as prebiotics. Conversely, 10- to 12-year-old plants presented a low concentration of free sugars and fructans with a maximum DPa of 70 monomers, which can be used to obtain fractions with high, intermediate and low DPa. These fractions have a potential use in the food industry as prebiotic, soluble fibers, stabilizers and sweeteners, among others. The agave varieties Agave spp., Agave salmiana, and Agave atrovirens showed mainly fructooligosaccharides (FOSs). Due to the presence of these low molecular carbohydrates, prebiotics, fermented products and/or syrups could be obtained. A. salmiana spp. crassipina and Agave tequilana variety cenizo presented DPa ≤50 and DPa ≤70, respectively, which could be useful in the production of fructan fractions of different DPa. These fractions might be used as functional ingredients in the manufacture of a wide range of food products.

In Vitro Digestibility and Quality of an Emulsified Meat Product Formulated With Animal Fat Encapsulated With Pectin.

Animal fat plays a key role in the structure, quality, and acceptability of emulsified meat products. However, a high consumption of saturated fat has been related to several health problems. Fat encapsulation with a nondigestible carbohydrate, such as pectin, may offer a promising alternative to reduce fat intake from a meat product, by preventing its digestion and absorption. The objective of this study was to develop a meat sausage with pectin-encapsulated-fat (PEF) to decrease its lipid digestibility, without compromising its acceptability. Pork fat particles encapsulation by emulsification with a 4% pectin solution, and also stability during meat processing and cooking, was confirmed by confocal microscopy. No changes (P > 0.05) compared to Control (C) were found on thermal stability and composition of sausages formulated with direct addition of pectin (T1) and with incorporation of PEF (T2). However, in comparison with C, pH, color, and texture of T1 and T2 samples were affected (P < 0.05). Nevertheless, these changes had no influence (P > 0.05) on sensory acceptability of treated samples, and actually improved (P < 0.05) their texture acceptance. In vitro digestive degradation of triacylglycerols was decreased (P < 0.05) by 20% on T2 samples compared to control and it was superior (P < 0.05) to T1 (8%). Confocal images confirmed lipid digestibility reduction of T2 samples. Incorporation of PEF in a meat sausage offers a better protection against the hydrolytic action of lipases over triaclyglycerides, than a direct addition of pectin, without affecting its sensory acceptability. Therefore, it can be a potential strategy to reduce fat intake from meat products. PRACTICAL APPLICATION: Reduction or replacement strategies tested to modify or decrease fat content in meat products usually leads to nondesirable sensory attributes. However, decreasing lipid digestibility by encapsulating animal fat with nondigestible pectin offers a new approach to reduce fat intake from full-animal-fat meat products, without affecting their sensory acceptability.

Increased anti-Helicobacter pylori effect of the probiotic Lactobacillus fermentum UCO-979C strain encapsulated in carrageenan evaluated in gastric simulations under fasting conditions.

Helicobacter pylori, a gastric carcinogenic pathogen, colonizes the stomach of 50% of the human population and is considered as a WHO priority 2 due to its antibiotics resistance. Therefore, research should aim to avoid H. pylori infection. Probiotics are an emerging alternative to handle this pathogen, making it necessary to have means to evaluate their effectiveness. This work evaluated the effect of a carrageenan encapsulated probiotic, Lactobacillus fermentum UCO-979C strain, against the pathogenic H. pylori SS1 strain under simulated gastric conditions (fasting or standard diet, pH 3.0 under microaerophilic condition and agitation). Samples were obtained from simulators up to 2.5 h after adding the probiotic, either planktonic or carrageenan encapsulated, and H. pylori were counted using enriched Columbia agar. Gastric simulations under fasting or standard diet showed collaboration between L. fermentum and carrageenan against the pathogen, it is undetectable at 1.5 or 2.5 h, respectively, allowing to conclude that the administration of the probiotic under fasting (harsher acid environment) provides a better anti-H. pylori effect that administering it associated with the diet. Thus, it can be suggested to consume low pH resistant probiotics under fasting.

Effect of blueberry extract, carriers, and combinations on the growth rate of probiotic and pathogenic bacteria.

The blueberry is recognised as a source of phenolic compounds that have beneficial effects on human health; however, they possess low bioavailability and can be degraded by gastrointestinal conditions. Encapsulation has been widely used to mitigate these disadvantages; Gum Arabic (GA) and Corn Syrup Solids (CSS) are common carriers used in this technique. The aim of this study was to evaluate the effect of Blueberry Extract (BE), carriers and their mixtures on the kinetic growth and maximal growth rate of probiotics and pathogenic bacteria. Kinetics were performed in MRS medium with and without a carbon source through Optical Density (OD) measurements and fitting these to the logistic model to compare the maximal growth rates (µmax) of the microorganisms. Each food component and its mixtures exert a different influence on the µmax of the bacteria studied (p < 0.05). This knowledge is important to improve the design of additives and functional foods.

Antimycotic Activity and Genotoxic Evaluation of Citrus sinensis and Citrus latifolia Essential Oils.

The aim of this study was to evaluate the antifungal activity of essential oils (EOs) of Citrus sinensis (C. sinensis) and Citrus latifolia (C. latifolia) against five Candida species: Candida albicans, Candida tropicalis, Candida glabrata, Candida lusitaniae and Candida guilliermondii; and perform its genotoxic evaluation. The EOs of C. sinensis and C. latifolia were obtained from the peel by hydro-distillation. The major components determined by GC-MS were in C. sinensis, d-limonene (96%) and α-myrcene (2.79%); and in C. latifolia, d-limonene (51.64%), ß-thujene (14.85%), ß-pinene (12.79%) and γ-terpinene (12.8%). Antifungal properties were studied by agar diffusion method, where C. sinensis presented low activity and C. latifolia essential oil was effective to inhibit growing of C. lusitaniae and C. guilliermondii with IC50 of 6.90 and 2.92 µg respectively. The minimum inhibitory concentrations (MIC) for C. sinensis were in a range of 0.42-3.71 µg and for C. latifolia of 0.22-1.30 µg. Genotoxic evaluation was done by Ames test where none of the oils induced point mutations. Flow cytometry was used to measure toxicity in human oral epithelial cells, C. sinensis was not cytotoxic and C. latifolia was toxic at 21.8 µg. These properties might bestow different odontological applications to each essential oil.

Ascorbic acid, ultraviolet C rays, and glucose but not hyperthermia are elicitors of human ß-defensin 1 mRNA in normal keratinocytes.

Hosts' innate defense systems are upregulated by antimicrobial peptide elicitors (APEs). Our aim was to investigate the effects of hyperthermia, ultraviolet A rays (UVA), and ultraviolet C rays (UVC) as well as glucose and ascorbic acid (AA) on the regulation of human ß-defensin 1 (DEFB1), cathelicidin (CAMP), and interferon-γ (IFNG) genes in normal human keratinocytes (NHK). The indirect in vitro antimicrobial activity against Staphylococcus aureus and Listeria monocytogenes of these potential APEs was tested. We found that AA is a more potent APE for DEFB1 than glucose in NHK. Glucose but not AA is an APE for CAMP. Mild hypo- (35°C) and hyperthermia (39°C) are not APEs in NHK. AA-dependent DEFB1 upregulation below 20 mM predicts in vitro antimicrobial activity as well as glucose- and AA-dependent CAMP and IFNG upregulation. UVC upregulates CAMP and DEFB1 genes but UVA only upregulates the DEFB1 gene. UVC is a previously unrecognized APE in human cells. Our results suggest that glucose upregulates CAMP in an IFN-γ-independent manner. AA is an elicitor of innate immunity that will challenge the current concept of late activation of adaptive immunity of this vitamin. These results could be useful in designing new potential drugs and devices to combat skin infections.