Search Results (31)

A naringenin-rich extract was obtained from Mexican oregano (Lippia graveolens Kunth) by supercritical CO₂ extraction and subjected to simulated gastrointestinal digestion to evaluate its potential to mitigate oxidative stress, reduce nitric oxide (NO) production, and enhance glucose uptake, an indicator of insulin resistance. Even after the simulated digestion, the extracts still showed activity, as the digested supercritical extract showed cellular antioxidant activity in colorectal adenocarcinoma (Caco-2) cells higher than 80%, increased glucose uptake in hepatocellular carcinoma HepG2 cells with insulin resistance by 29.9% and decreased NO production in 38.1% in murine macrophages (RAW 264.7). The methanolic extract showed similar results but led to higher NO production. In general, supercritical CO₂ extraction yields higher flavonoid content in oregano extract than conventional methanolic extraction, as reflected in the biological activities; moreover, the green nature of the process supports the development of functional ingredients. Full article

Candida albicans is an opportunistic fungus capable of forming biofilms that are resistant to conventional antifungal treatments. This study evaluated the antibiofilm activity of an ethanolic extract from Mexican oregano (Lippia graveolens Kunth) stem and its impact on the protein composition of the C. albicans cell wall (CW). The proteomic analysis was restricted to the adherent cells that persisted after treatment, representing the more tolerant subpopulation. First, the biofilm-forming capacity of 18 clinical isolates was characterized. Subsequently, the effect of the Lippia graveolens Kunth stem extract on biofilm formation was assessed in clinical isolates of C. albicans with high and moderate biofilm-forming capacities. The results showed an MIC₉₀ of 16 mg/mL against C. albicans isolates in planktonic growth. Furthermore, the extract exhibited an antibiofilm effect, showing a 77% inhibition in the highly biofilm-forming C. albicans 2400H strain at 1.6 mg/mL. To assess how the extract influences CW composition, we analyzed the CW proteome of the adherent biofilm cells of C. albicans that persisted after exposure to the stem extract. Mass spectrometry identified 1006 total proteins, where 156 were up-regulated, and 94 were down-regulated. Of the differentially expressed proteins, we identify 40 CW proteins (CWP’s) associated with dimorphic transition, adhesion, oxidative stress, and biofilm formation. These findings provide the potential of the L. graveolens Kunth stem as a natural antifungal agent against C. albicans biofilms. In addition, we identified CWP’s associated with tolerance to the extract’s antibiofilm activity, offering mechanistic insight into persistence and potential targets for improving antibiofilm interventions. Full article

Candida albicans is a major opportunistic fungal pathogen whose increasing resistance to antifungal agents requires new alternative therapies. This study evaluated the antifungal potential of Lippia graveolens (Mexican oregano) essential oil, with particular emphasis on its effects on key C. albicans virulence factors. The chemical composition of the essential oil was determined by GC–MS, identifying carvacrol and thymol as abundant components. Antifungal activity was assessed via disk diffusion, broth microdilution, and time-kill kinetics against clinical and reference Candida strains. The essential oil showed potent fungicidal activity, with MIC and MFC values of 2 mg/mL and 3 mg/mL, respectively. In addition to demonstrating antifungal potency, this work focused on C. albicans virulence factors, revealing that L. graveolens essential oil significantly inhibited germ tube formation at 1 mg/mL and completely suppressed both germ tube and biofilm development at concentrations ≥ 2 mg/mL, along with dose-dependent disruption of fungal membrane integrity. These findings highlight the multifactorial mechanisms by which L. graveolens essential oil affects C. albicans pathogenicity. This study supports its potential as a natural antifungal agent and a valuable adjuvant in the treatment of resistant candidiasis. Full article

Background/Objectives: The search for natural alternatives in breast cancer (BC) management has spurred interest in plant-derived extracts, particularly oregano variants and their bioactive compound carvacrol (Cv). However, Mexican oregano (Lippia graveolens) infusion (MoI) remains unexplored. This study aimed to chemically characterize MoI and compare its anticancer effects with Cv across BC cell lines, including aggressive triple-negative (TN) subtypes. Methods: MoI was analyzed for composition, antioxidant capacity (ABTS, DPPH, FRAP, total phenols/flavonoids), and phytochemical profile (FTIR, HPLC). Anticancer activity was assessed via MTT and LDH assays. Results: MoI exhibits strong antioxidant capacity and concentration-dependent antiproliferative effects, with IC50 values ranging from 0.08 to 0.18 mg/mL across BC lines, significantly higher (i.e., less cytotoxic) than Cv IC50 of 121–211 µM. Importantly, MoI displayed markedly lower cytotoxicity toward non-cancerous cells (IC50 0.18 mg/mL) compared to Cv (IC50 110 µM). Conclusions: While both agents reduced metabolic activity, Cv induced a more acute suppression. These findings position MoI as a promising, selective candidate for BC therapy, particularly for poor-prognosis subtypes like TN BC, warranting further mechanistic investigation. Full article

Some oregano species have been related to antiproliferative activity against various types of cancer cells, such as colon, liver, and breast; this has been mainly associated with their rich content of flavonoid-type compounds due to their ability to induce the activation of intracellular signaling pathways, such as apoptosis induction. This study aimed to determine the antiproliferative activity mechanism of the polyphenol extract of Mexican oregano (Lippia graveolens Kunth) on MDA-MB-231 breast cancer cells. The flavonoid content with the antiproliferative potential was quantified by ESI-QTOF-MS/MS chromatography, finding naringenin in a higher concentration (7758.71 µg/g extract) compared to the other identified compounds (quercetin, luteolin, and apigenin). Subsequently, the cytotoxicity of the extract was evaluated in the normal human fibroblasts CCD-18Co cell line, where the extract did not present cytotoxic activity at the evaluated concentration (150 µg/mL). In MDA-MB-231 cells treated with the same extract concentration, the activation of proteins associated with apoptosis was observed by western blot. Therefore, the previous antiproliferative activity shown by this extract on breast cancer cells may be due to the activation of this cell death pathway. Thus, the polyphenol extract of Mexican oregano L. graveolens has the potential for future research as an adjuvant in treating breast cancer. Full article

Meat products are highly susceptible to contamination with Listeria monocytogenes, a foodborne pathogen associated with high mortality. To mitigate this risk, this study explored the use of Poliomintha longiflora oregano essential oil, both in its pure (PEO) and fractionated (FIV, fraction IV obtained at 140 °C) forms, as part of a hurdle technology combining natural antimicrobials with mild thermal treatments. In vitro thermal inactivation experiments were conducted at 52, 54, 57.5, and 63 °C using a simulated meat medium. The FIV group, characterized by 60.23% carvacrol and 21.17% thymol, exhibited significantly enhanced bactericidal activity, achieving up to 5.5 log-reductions in L. monocytogenes at 57.5 °C within 3 min, compared to <2 log-reductions for the control group. Inactivation kinetics were well described by the Weibull–Mafart model. The δ-values, defined as the time required to achieve a 1-log reduction in bacterial population, were consistently lower for FIV compared to the control across all tested temperatures (e.g., δ₅₂°C = 0.64 min vs. 8.47 min for control). The estimated z-values, which represent the temperature increase required to achieve a tenfold change in δ-value, were 5.75 °C (control), 5.20 °C (PEO), and 5.00 °C (FIV), suggesting a consistent thermal sensitivity but enhanced inactivation efficacy with the essential oils. These findings suggest that fractionated oregano essential oil is a promising hurdle to shorten thermal treatments in meat products, thereby lowering L. monocytogenes contamination risk while preserving product quality. Full article

This work reports the synthesis of two monometallic catalysts, Cu/Al₂O_3, and Pd/Al₂O₃, using a green approach based on Mexican oregano (Lippia graveolens), a common food condiment. Its extract has been largely overlooked as a high-technology reactive for synthesizing catalysts, metallic or oxide nanoparticles, unlike other green leaf plants. The green synthesis was compared with a conventional catalyst synthesis methodology using commercial chemical reducing agents. Oregano extract shows promise for novel applications extending beyond its culinary use, valorizing it as a chemical reducer to produce catalysts. Thus, this kind of application could significantly elevate the value of oregano, empowering communities that rely on its cultivation for economic benefit and transforming the plant from a low-profit agro-industrial product to a high-added-value crop. The reduction kinetics involved in the formation of nanoparticles were monitored up to the first stage of nucleation and a first-order model adequately described the data. Activation energy analysis showed that the chemical reaction mechanism has a dominant role in controlling the reaction, compared to mass transfer effects. Notoriously, the Pd/Al₂O₃ green synthesis catalyst showed the smallest mean particle size (4.85 ± 1.30 nm). These findings underscore the potential of green synthesis as an economically viable and environmentally friendly alternative for producing catalysts. Concerning the 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) as a biomass-derived molecule, its oxidation with H₂O₂ using both Pd/Al₂O₃ catalysts (by green and chemical synthesis methods) exhibited significantly higher selectivity toward 2,5-diformylfuran (DFF) compared to Cu/Al₂O₃ catalysts, suggesting a possible inhibitory effect. Full article

Botanical extracts are being considered for integration into disease management programs to control plant pathogenic fungi and oomycetes. A promising extract with potential is the essential oil of Lippia graveolens. However, its extraction process has not been optimized. Since optimizing process conditions can impact fungicidal and/or oomyceticidal effects, this research implemented time, temperature, and solid/liquid ratio conditions to maximize the fungicidal and oomyceticidal effects. The effectiveness was evaluated through parameters of mycelial growth inhibition, spore germination inhibition, minimum inhibitory and fungicidal/oomyceticidal concentration for the fungi Gilbertella persicaria, Agroathelia rolfsii, and Colletotrichum gloeosporioides, as well as the oomycete Phytophthora capsici. Optimal conditions were as follows: time: 46.27 min; temperature: 329.34 °C; and solid/liquid ratio: 80.35 g/L. In general, the optimized treatment was more effective in A. rolfsii ≥ P. capsica > G. persicaria ≥ C. gloeosporioides in all assays. These results demonstrate the fungicidal and oomiceticidal effects of L. graveolens essential oil, with potential for commercial product formulation. Full article

Food security is essential to ensure everyone can access sufficient nutritious food. Cereals and legumes are fundamental foods worldwide. Phaseolus vulgaris L., the common bean, is an essential staple food in many nations worldwide. However, it is vulnerable to fusariosis, a disease caused by the fungus Fusarium spp. that can significantly decrease crop quality and yield. To combat plant diseases, industrial residues and plant residues are valuable due to their bioactive compounds with biotechnological applications. This study proposes using ethanolic extracts with phytochemical compounds, such as flavonoids, different from those reported in essential oils, to reduce the growth of Fusarium species both in vitro and in vivo. Industrial residues that are produced after extracting essential oils offer a promising alternative to develop organic biopesticides, promoting more sustainable and environmentally friendly agriculture. Full article

The Mexican oregano by-products are a source of bioactive molecules (polyphenols) that could be extracted using solid-state fermentation (SSF). This study fermented the by-products via SSF (120 h) with a lactic acid bacteria (LAB) Leuconostoc mesenteroides. Sequentially, a bioactive and chemical determination was made according to the phenolic content, antioxidant activity (DPPH^●/FRAP), bioactive properties (α-amylase inhibition and antimicrobial activity against Escherichia coli), and chemical composition (HPLC-MS). The results showed that the total phenolics and flavonoid content, as well as the antioxidant activity, increased (0.60, 2.55, and 3.01 times, respectively) during the SSF process compared with unfermented material. Also, the extracts showed antimicrobial activity against E. coli and α-amylase inhibition. These inhibitory results could be attributed to bioactive compounds identified via HPLC, such as gardenin B, trachelogenin, ferulic acid, and resveratrol 3-O-glucoside. Therefore, the application of L. mesenteroides under SSF on oregano by-products comprises an eco-friendly strategy for their valorization as raw materials for the recovery of phenolic compounds that could be natural alternatives against synthetic antioxidant and antimicrobial agents, promoting a more circular and sustainable supply system within the oregano industry. Full article

Essential oils are emerging as alternatives to conventional pest control chemicals. Lippia graveolens Kunth (Mexican oregano) is a source of essential oils and during conventional extraction, the biomass generated is discarded as waste; however, reports show that this biomass is still a rich source of essential oils. Conventional essential oil extraction causes contamination and utilizes toxic solvents. Deep eutectic solvents (DESs) offer low toxicity, biodegradability, high selectivity, and yields comparable to organic solvents. This study obtained essential oil from Lippia graveolens biomass via hydrodistillation with ultrasound-assisted DES pretreatment. This research aimed to optimize the extraction of essential oil from Lippia graveolens biomass using ultrasound-assisted DESs and assess its in vitro and in vivo inhibitory effect on C. asianum. The response variables were extraction yield and total reducing capacity. Optimal conditions were determined using a central composite rotatable design, considering solid-to-liquid ratio (0.38 g/mL), ultrasonic amplitude (45.05%), and time (7.47 min). The optimized oil, with thymol (48%) as the predominant component, exhibited more volatile compounds than conventional hydrodistillation. Fungicidal assays highlighted its potential in controlling anthracnose in papaya fruits caused by C. asianum, making ultrasound-assisted DES pretreatment a promising alternative for obtaining essential oil from botanical byproducts. Full article

In this research, several analyses were carried out on concentrated fractions of Mexican oregano essential oil (Poliomintha longiflora Gray) in order to determine its ability to inhibit the growth and the motility of Escherichia coli (swimming), Pseudomonas aeruginosa (swimming), and Proteus vulgaris (swarming); these Gram-negative bacteria associated with urinary tract infections are motile due to the presence of flagella, which is considered an important virulence factor that favors their motility when trying to reach the target organ and cause an infection. Also, the resistance pattern to antibiotics of each strain was determined. The results showed resistance pattern (8 out of 12 antibiotics tested) for P. aureginosa, while E. coli and P. vulgaris were resistant to 4 antibiotics out of the 12 tested. On the other hand, fractionated oregano caused an inhibition of growth and a reduction in motility, varying between fractions and among bacteria. Fraction 4 showed major growth reduction, with MBC values ranging from 0.002 to 23.7 mg/mL. Treatment with fractionated oregano (F1, F2, F3, F4) reduced the motility by 92–81% for P. vulgaris, 90–83% for E. coli, and 100–8.9% for P. aeruginosa. These results demonstrated a higher performance with a lower application dose due to its high content of Carvacrol and Thymol; unlike other concentrated fractions, this synergy of oxygenated monoterpenes may cause greater antimicrobial activity. Full article

This research focuses on assessing the synergistic effects of Mexican oregano (Lippia graveolens) essential oil or carvacrol when combined with the antibiotic imipenem, aiming to reduce the pathogenic viability and virulence of Acinetobacter baumannii and Pseudomonas aeruginosa. The study highlighted the synergistic effect of combining L. graveolens essential oil or carvacrol with imipenem, significantly reducing the required doses for inhibiting bacterial growth. The combination treatments drastically lowered the necessary imipenem doses, highlighting a potent enhancement in efficacy against A. baumannii and P. aeruginosa. For example, the minimum inhibitory concentrations (MIC) for the essential oil/imipenem combinations were notably low, at 0.03/0.000023 mg/mL for A. baumannii and 0.0073/0.000023 mg/mL for P. aeruginosa. Similarly, the combinations significantly inhibited biofilm formation at lower concentrations than when the components were used individually, demonstrating the strategic advantage of this approach in combating antibiotic resistance. For OXA-51, imipenem showed a relatively stable interaction during 30 ns of dynamic simulation of their interaction, indicating changes (<2 nm) in ligand positioning during this period. Carvacrol exhibited similar fluctuations to imipenem, suggesting its potential inhibition efficacy, while thymol showed significant variability, particularly at >10 ns, suggesting potential instability. With IMP-1, imipenem also displayed very stable interactions during 38 ns and demonstrated notable movement and positioning changes within the active site, indicating a more dynamic interaction. In contrast, carvacrol and thymol maintained their position within the active site only ~20 and ~15 ns, respectively. These results highlight the effectiveness of combining L. graveolens essential oil and carvacrol with imipenem in tackling the difficult-to-treat pathogens A. baumannii and P. aeruginosa. Full article

The sand fly, Phlebotomus papatasi (Scopoli, 1786), is a major vector for Leishmania major in the Middle East, which has impacted human health and US military operations in the area, demonstrating the need to develop effective sand fly control and repellent options. Here, we report the results of spatial repellency and avoidance experiments in a static air olfactometer using the female P. papatasi testing essential oils of Lippia graveolens (Mexican oregano), Pimenta dioica (allspice), Amyris balsamifera (amyris), Nepeta cataria (catnip), Mentha piperita (peppermint), and Melaleuca alternifolia (tea tree); the 9–12 carbon saturated fatty acids (nonanoic acid, decanoic acid, undecanoic acid, and dodecanoic acid); and the synthetic repellents DEET and IR3535. The materials applied at 1% exhibited varying activity levels but were not significantly different in mean repellency and avoidance from DEET and IR3535, except in regards to nonanoic acid. Some materials, particularly nonanoic and undecanoic acids, produced sand fly mortality. The observed trends in mean repellency over exposure time included the following: (1) P. dioica oil, M. alternifolia oil, decanoic acid, undecanoic acid, DEET, and IR3535 exhibited increasing mean repellency over time; (2) oils of N. cataria, A. balsamifera, M. piperita, and dodecanoic acid exhibited relatively constant mean repellency over time; and (3) L. graveolens oil and nonanoic acid exhibited a general decrease in mean repellent activity over time. These studies identified the essential oils of N. cataria and A. balsamifera as effective spatial repellents at reduced concentrations compared to those of DEET. Additional research is required to elucidate the modes of action and potential synergism of repellents and essential oil components for enhanced repellency activity. Full article

In recent years, the determination of the antioxidant and antibacterial activity of essential oils in wild plants, such as Mexican oregano (Lippia graveolens Kunth), has become increasingly important. The objective was to compare the antioxidant and antibacterial activity of Mexican oregano essential oil obtained from plants occurring naturally in semiarid areas (Wild1 and Wild2), and those cultivated in the field (CField) and greenhouse (CGreenhouse) in northern Mexico. The Mexican oregano essential oil extraction was performed using the hydrodistillation method, the antioxidant activity was determined using the ABTS method, and the antibacterial activity was assessed through bioassays under the microwell method at nine different concentrations. The aim was to determine the diameter of the inhibition zone and, consequently, understand the sensitivity level for four bacterial species. The results revealed an antioxidant activity ranging from 90% to 94% at the sampling sites, with Wild1 standing out for having the highest average antioxidant activity values. Likewise, six out of the nine concentrations analyzed showed some degree of sensitivity for all the sampling sites. In this regard, the 25 µL mL⁻¹ concentration showed the highest diameter of inhibition zone values, highlighting the Wild2 site, which showed an average diameter greater than 30 mm for the four bacteria tested. Only in the case of S. typhi did the CGreenhouse site surpass the Wild2, with an average diameter of the inhibition zone of 36.7 mm. These findings contribute to the search for new antioxidant and antibacterial options, addressing the challenges that humanity faces in the quest for opportunities to increase life expectancy. Full article