Lippia grata Essential Oil Acts Synergistically with Ampicillin Against Staphylococcus aureus and its Biofilm.

Antimicrobial resistance (AMR) presents a global challenge as microorganisms evolve to withstand the effects of antibiotics. In addition, the improper use of antibiotics significantly contributes to the AMR acceleration. Essential oils have garnered attention for their antimicrobial potential. Indeed, essential oils extracted from plants contain compounds that exhibit antibacterial activity, including against resistant microorganisms. Hence, this study aimed to evaluate the antimicrobial and antibiofilm activity of the essential oil (EO) extracted from Lippia grata and its combination with ampicillin against Staphylococcus aureus strains (ATCC 25923, ATCC 700698, and JKD6008). The plant material (leaves) was gathered in Mossoro, RN, and the EO was obtained using the hydrodistillation method with the Clevenger apparatus. The antimicrobial activity of the EO was assessed through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Antibiofilm activity was evaluated by measuring biomass using crystal violet (CV) staining, viable cell counting, and analysis of preformed biofilms. In addition, the synergistic effects of the EO in combination with ampicillin were examined by scanning electron and confocal microscopy. The EO displayed a MIC value of 2.5 mg/mL against all tested S. aureus strains and an MBC only against S. aureus JKD6008 at 2.5 mg/mL. L. grata EO caused complete biofilm inhibition at concentrations ranging from 10 to 0.312 mg/mL against S. aureus ATCC 25923 and 10 to 1.25 mg/mL against S. aureus ATCC 700698 and S. aureus JKD6008. In the viable cell quantification assay, there was a reduction in CFU ranging from 1.0 to 8.0 logs. The combination of EO with ampicillin exhibited a synergistic effect against all strains. Moreover, the combination showed a significantly inhibiting biofilm formation and eradicating preformed biofilms. Furthermore, the EO and ampicillin (individually and in combination) altered the cellular morphology of S. aureus cells. Regarding the mechanism, the results revealed that L. grata EO increased membrane permeability and caused significant membrane damage. Concerning the synergy mechanism, the results revealed that the combination of EO and ampicillin increases membrane permeability and causes considerable membrane damage, further inhibiting bacteria synergistically. The findings obtained here suggest that L. grata EO in combination with ampicillin could be a viable treatment option against S. aureus infections, including MRSA strain.

Antifungal chemosensitization through induction of oxidative stress: A model for control of candidiasis based on the Lippia origanoides essential oil.

In this work, evaluated the antifungal chemosensitizing effect of the Lippia origanoides essential oil (EO) through the induction of oxidative stress. The EO was obtained by hydrodistillation and analyzed by GC-MS. To evaluate the antifungal chemosensitizing effect through induction of oxidative stress, cultures of the model yeast Saccharomyces cerevisiae ∆ycf1 were exposed to sub-inhibitory concentrations of the EO, and the expression of genes known, due be overexpressed in response to oxidative and mutagenic stress was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) method. Carvacrol and thymol were identified as the main components. The EO was effective in preventing or reducing the growth of the microorganisms tested. The gene expression profiles showed that EO promoted changes in the patterns of expression of genes involved in oxidative and mutagenic stress resistance. The combined use of the L. origanoides EO with fluconazole has been tested on Candida yeasts and the strategy resulted in a synergistic enhancement of the antifungal action of the azolic chemical product. Indeed, in association with EO, the fluconazole MICs dropped. Thus, the combinatorial use of L. origanoides EO as a chemosensitizer agent should contribute to enhancing the efficiency of conventional antifungal drugs, reducing their negative side effects.

Insecticidal action, repellency, and toxicity mechanism of the essential oil of Lippia turbinata against the stored product pest Rhipibruchus picturatus (F.).

The use of essential oils (EOs) in the development of alternative management methods for bruchid control under storage conditions aroused great interest because they have proven to be effective, less toxic, and less persistent in the ecosystem than synthetic pesticides. In this sense, leaves of Lippia turbinata (Griseb.) Moldenke EO were studied in the present work. The monoterpene limonene and the monoterpenoid eucalyptol were its main constituents. EO showed a potent insecticidal activity, both in contact and fumigant conditions, against Rhipibruchus picturatus (F.) which is one of the main pests of Prosopis alba pods in stored conditions. Moreover, the EO produces repellency in these insects. Additionally, the toxicity mechanism of action was studied. In this regard, the EO inhibits the acetylcholinesterase enzyme in in vitro assays, alters the activity of the antioxidant enzymes superoxide dismutase and catalase, and produces an increase in the lipid peroxidation reactions. This is the first report of the use of the L. turbinata EO against R. picturatus insect pest. The data obtained demonstrate its potential for developing more efficient and natural storage pest control strategies.

Seasonal and Circadian Variation of Non-Volatile Metabolites in Lippia alba Leaves.

The present study describes the seasonal and circadian variations of the major compounds from Lippia alba leaves. SPSS was used to identify, quantify, and associate the variations in the secondary metabolites of this species through HPLC/DAD analysis of the leaves hydroethanolic extracts of six selected L. alba specimens. For the circadian study, the samples were collected at four different daily hours in each year's season. For the seasonal study, the samples were collected monthly from the same individuals for two consecutive years (2018 and 2019). These samples were analyzed and quantified using a validated HPLC method for flavonoids, iridoids, and phenyl ethanoid glycoside. Mussaenoside, acteoside, and tricin-7-O-diglucuronide showed a moderate positive correlation between their biosynthesis and the precipitation index, while epi-loganin had a moderate negative correlation. Acteoside showed a moderate positive correlation between the minimum registered temperature and its production. Compared with previous studies, a drastic reduction (about 95 %) in the production of tricin-7-O-diglucuronide compared with previous study and this difference could be attributed to the plant's aging. Thus, the data demonstrated that lower temperatures and high rainfall could favor the production of the major L. alba active compounds (acteoside and tricin-7-O-diglucuronide) and that older plants harm their production.

Wound Healing Effect of Lippia sidoides and Myracrodruon urundeuva Nanogel.

Wound healing is a natural regenerative response to tissue injury and the conventional treatments consists of the use wound dressings with local administration of medicines, but, in some cases, are only partially effective and limited by toxicity or ineffective anti-microbial protection. Medicinal plants such as Lippia sidoides and Myracrodruon urundeuva have shown interesting pharmacological activities, allied to this, the association of these medicinal plants and nanotechnology, could mean an advantage in relation to classical approach. This study investigated the effect of a nanogel loaded with Lippia sidoides essential oil and Myracrodruon urundeuva extract (NAA) in an excisional wound healing model in rats. Animals were anesthetized and skin wounds were made using a metal punch. The groups were treated with vehicle, NAA or collagenase gel, for 7, 14 or 21 days and then sacrificed for tissue analysis. NAA did not show acute dermal irritation, further significantly reduced (p<0.05) the final wound area, accelerated the wound contraction and organization of collagen in the group treated for 14 days. The data presented here demonstrate the therapeutic potential for the use of nanotechnology associated with medicinal plants and provides evidence that corroborate with the use of L. sidoides and M. urundeuva as healing medicinal plants.

Ippia Alba Essential Oil: A Promising Complementary Therapy for Breast Cancer.

Breast cancer remains a pressing global health issue, spurring exploration into innovative therapies. This review focuses on Lippia alba (Mill.) essential oil's potential as a complementary breast cancer treatment. With growing interest in natural approaches, Lippia alba shows promise in breast cancer management. The review will explore Lippia alba's multifaceted role in treatment, highlighting its anticancer effects on breast cancer cells, potential synergy with conventional treatments, safety profiles, and existing clinical evidence. It will also address knowledge gaps, stressing the need for further research to unlock Lippia alba's full therapeutic potential in breast cancer therapy. In a field craving novel therapies, this review offers a timely analysis. Despite the lack of existing reviews on this topic, Lippia alba's significance cannot be understated. As research progresses, this article will be a valuable resource for researchers and healthcare practitioners seeking to augment breast cancer management through complementary therapies.

In vitro Safety Assessment of Extracts and Compounds From Plants as Sunscreen Ingredients.

This work investigated the safety of extracts obtained from plants growing in Colombia, which have previously shown UV-filter/antigenotoxic properties. The compounds in plant extracts obtained by the supercritical fluid (CO2) extraction method were identified using gas chromatography coupled to mass spectrometry (GC/MS) analysis. Cytotoxicity measured as cytotoxic concentration 50% (CC50) and genotoxicity of the plant extracts and some compounds were studied in human fibroblasts using the trypan blue exclusion assay and the Comet assay, respectively. The extracts from Pipper eriopodon and Salvia aratocensis species and the compound trans-ß-caryophyllene were clearly cytotoxic to human fibroblasts. Conversely, Achyrocline satureioides, Chromolaena pellia, and Lippia origanoides extracts were relatively less cytotoxic with CC50 values of 173, 184, and 89 µg/mL, respectively. The C. pellia and L. origanoides extracts produced some degree of DNA breaks at cytotoxic concentrations. The cytotoxicity of the studied compounds was as follows, with lower CC50 values representing the most cytotoxic compounds: resveratrol (91 µM) > pinocembrin (144 µM) > quercetin (222 µM) > titanium dioxide (704 µM). Quercetin was unique among the compounds assayed in being genotoxic to human fibroblasts. Our work indicates that phytochemicals can be cytotoxic and genotoxic, demonstrating the need to establish safe concentrations of these extracts for their potential use in cosmetics.

Nanostructured lipid carriers loaded with essential oils: a strategy against SARS-CoV-2.

This work aimed to investigate the effectiveness of Lippia sidoides and Syzygium aromaticum essential oils (EOs) encapsulated in nanostructured lipid carriers (NLCs) as SARS-CoV-2 inhibitors through virucidal activity assessment. We developed anionic and cationic NLCs loaded with the EOs and assessed their physicochemical properties and SARS-CoV-2 virucidal activity, focusing on the effects of EO type and the NLCs composition. The NLCs exhibited particle sizes of 141.30 to 160.53 nm for anionic and 109.30 to 138.60 nm for cationic types, with PDIs between 0.16 and 0.25. High zeta potentials (>29.0 in modulus) indicated stable formulations. The NLCs effectively encapsulated the EOs, achieving encapsulation efficiencies between 84.6 to 100% w/w of marker compound. The EOs-loaded NLCs reduced the SARS-CoV-2 virion count, exceeding 2 logs over the control. NLCs loaded with Lippia sidoides and Syzygium aromaticum EOs represent an innovative strategy for combating SARS-CoV-2.

Antioxidant Properties of Lippia alba Essential Oil: A Potential Treatment for Oxidative Stress-Related Conditions in Plants and Cancer Cells.

Lippia alba (Mill.) N.E.Br. ex Britton and P. Wilson is used in folk medicine of Central and South America for its biological activities: i.e., antifungal, antibacterial, antiviral, and anti-inflammatory. Based on ethnopharmacological information and the increasing interest in this species, this work aimed to test a possible wide use of its essential oil (EO) in pharmaceutical and horticultural applications. Therefore, we focused the attention on the antioxidant activity of the oil as a possible tool to overcome the oxidative stress in both applications. For this purpose, we have chosen three aggressive breast cancer cell lines and two horticultural species (Solanum lycopersicum L. and Phaseolus acutifolius L.) that are very sensitive to salt stress. We determined the antioxidant activity of L. alba EO through the quantification of phenols and flavonoids. Regarding tomato and bean plants under salt stress, L. alba EO was used for the first time as a seed priming agent to enhance plant salt tolerance. In this case, the seed treatment enhanced the content of phenolic compounds, reduced power and scavenger activity, and decreased membrane lipid peroxidation, thus mitigating the oxidative stress induced by salt. While in breast cancer cells the EO treatment showed different responses according to the cell lines, i.e., in SUM149 and MDA-MB-231 the EO decreased proliferation and increased antioxidant activity and lipid peroxidation, showing high cytotoxic effects associated with the release of lactate dehydrogenase, vice versa no effect was observed in MDA-MB-468. Such antioxidant activity opens a new perspective about this essential oil as a possible tool to counteract proliferation in some cancer cell lines and in horticulture as a seed priming agent to protect from oxidative damage in crops sensitive to salinity.

Application of MaxEnt modeling to evaluate the climate change effects on the geographic distribution of Lippia javanica (Burm.f.) Spreng in Africa.

Lippia javanica is a typical indigenous plant species mostly found in the higher elevation or mountainous regions in southern, central, and eastern Africa. The ongoing utilization of the species for ethnobotanical applications and traditional uses, coupled with the changing climate, increases the risk of a potential reduction in its geographic distribution range in the region. Herein, we utilized the MaxEnt species distribution modelling to build the L. javanica distribution models in tropical and subtropical African regions for current and future climates. The MaxEnt models were calibrated and fitted using 286 occurrence records and six environmental variables. Temperatures, including temperature seasonality [Bio 4] and the maximum temperature of the warmest month [Bio 5], were observed to be the most significant determinants of L. javanica's distribution. The current projected range for L. javanica was estimated to be 2,118,457 km2. Future model predictions indicated that L. javanica may increase its geographic distribution in western areas of the continent and regions around the equator; however, much of the geographic range in southern Africa may shift southwards, causing the species to lose portions of the northern limits of the habitat range. These current findings can help increase the conservation of L. javanica and other species and combat localized species loss induced by climate change and human pressure. We also emphasize the importance of more investigations and enhanced surveillance of traditionally used plant species in regions that are acutely susceptible to climate change.

Evaluation of Lippia scaberrima Sond. and Aspalathus linearis (Burm.f.) R. Dahlgren extracts on human CYP enzymes and gold nanoparticle synthesis: implications for drug metabolism and cytotoxicity.

BACKGROUND: Metabolism is an important component of the kinetic characteristics of herbal constituents, and it often determines the internal dose and concentration of these effective constituents at the target site. The metabolic profile of plant extracts and pure compounds need to be determined for any possible herb-drug metabolic interactions that might occur. METHODS: Various concentrations of the essential oil of Lippia scaberrima, the ethanolic extract of Lippia scaberrima alone and their combinations with fermented and unfermented Aspalathus linearis extract were used to determine the inhibitory potential on placental, microsomal and recombinant human hepatic Cytochrome P450 enzymes. Furthermore, the study investigated the synthesis and characterization of gold nanoparticles from the ethanolic extract of Lippia scaberrima as a lead sample. Confirmation and characterization of the synthesized gold nanoparticles were conducted through various methods. Additionally, the cytotoxic properties of the ethanolic extract of Lippia scaberrima were compared with the gold nanoparticles synthesized from Lippia scaberrima using gum arabic as a capping agent. RESULTS: All the samples showed varying levels of CYP inhibition. The most potent inhibition took place for CYP2C19 and CYP1B1 with 50% inhibitory concentration (IC50) values of less than 0.05 µg/L for the essential oil tested and IC50-values between 0.05 µg/L-1 µg/L for all the other combinations and extracts tested, respectively. For both CYP1A2 and CYP2D6 the IC50-values for the essential oil, the extracts and combinations were found in the range of 1 - 10 µg/L. The majority of the IC50 values found were higher than 10 µg/L and, therefore, were found to have no inhibition against the CYP enzymes tested. CONCLUSION: Therefore, the essential oil of Lippia scaberrima, the ethanolic extract of Lippia scaberrima alone and their combinations with Aspalathus linearis do not possess any clinically significant CYP interaction potential and may be further investigated for their adjuvant potential for use in the tuberculosis treatment regimen. Furthermore, it was shown that the cytotoxic potential of the Lippia scaberrima gold nanoparticles was reduced by twofold when compared to the ethanolic extract of Lippia scaberrima.

Supercritical CO2 extraction of naringenin from Mexican oregano (Lippia graveolens): its antioxidant capacity under simulated gastrointestinal digestion.

A supercritical CO2 method was optimized to recover naringenin-rich extract from Mexican oregano (Lippia graveolens), a flavanone with high antioxidant and anti-inflammatory activity. The effect of the extraction parameters like pressure, temperature, and co-solvent on naringenin concentration was evaluated. We used response surface methodology to optimize the naringenin extraction from oregano; the chemical composition by UPLC-MS of the optimized extract and the effect of simulated gastrointestinal digestion on its antioxidant capacity and total phenolic content were also evaluated. The optimum conditions were 58.4 °C and 12.46% co-solvent (ethanol), with a pressure of 166 bar, obtaining a naringenin content of 46.59 mg/g extract. Also, supercritical optimized extracts yielded high quantities of cirsimaritin, quercetin, phloridzin, apigenin, and luteolin. The results indicated that the naringenin-rich extract obtained at optimized conditions had higher total phenolic content, antioxidant capacity by TEAC and ORAC, and flavonoid content, compared with the methanolic extract, and the simulated gastrointestinal digestion reduced all these values.

Biological effects of Lippia alba essential oil against Anopheles gambiae and Aedes aegypti.

The management of mosquito resistance to chemical insecticides and the biting behaviour of some species are motivating the search for complementary and/or alternative control methods. The use of plants is increasingly considered as a sustainable biological solution for vector control. The aim of this study was to evaluate the biological effects of the essential oil (EO) of Lippia alba harvested in Abidjan (Côte d'Ivoire) against Anopheles gambiae and Aedes aegypti mosquitoes. Phytochemical compounds were identified by GC-MS. Knockdown and mortality were determined according to the WHO test tube protocol. Contact irritancy was assessed by observing the movement of mosquitoes from a treated WHO tube to a second untreated tube. Non-contact repellency was assessed using a standardised high-throughput screening system (HITSS). Blood meal inhibition was assessed using a membrane feeding assay treated with EO. The EO was identified as the citral chemotype. The EO gave 100% KD60 in both species at a concentration of 1%. Mortalities of 100% were recorded with An. gambiae and Ae. aegypti at concentrations of 1% and 5% respectively. The highest proportions of females escaping during the contact irritancy test were 100% for An. gambiae at 1% concentration and 94% for Ae. aegypti at 2.5% concentration. The 1% concentration produced the highest proportions of repelled mosquitoes in the non-contact repellency tests: 76.8% (An. gambiae) and 68.5% (Ae. aegypti). The blood meal inhibition rate at a dose of 10% was 98.4% in Ae. aegypti but only 15.5% in An. gambiae. The citral chemotype of L. alba EO has promising biological effects in both species that make it a potentially good candidate for its use in mosquito control. The results obtained in this study encourage the further evaluation of L. alba EOs from other localities and of different chemotypes, under laboratory and field conditions.

Assessment of Antimicrobial and Cytotoxic Activities of Liposomes Loaded with Curcumin and Lippia origanoides Essential Oil.

(1) Introduction: Curcumin and Lippia origanoides essential oils have a broad spectrum of biological activities; however, their physicochemical instability, low solubility, and high volatility limit their therapeutic use. Encapsulation in liposomes has been reported as a feasible approach to increase the physicochemical stability of active substances, protect them from interactions with the environment, modulate their release, reduce their volatility, improve their bioactivity, and reduce their toxicity. To date, there are no reports on the co-encapsulation of curcumin and Lippia origanoides essential oils in liposomes. Therefore, the objective of this work is to prepare and physiochemical characterize liposomes loaded with the mixture of these compounds and to evaluate different in vitro biological activities. (2) Methods: Liposomes were produced using the thin-layer method and physiochemical characteristics were calculated. The antimicrobial and cytotoxic activities of both encapsulated and non-encapsulated compounds were evaluated. (3) Results: Empty and loaded nanometric-sized liposomes were obtained that are monodisperse and have a negative zeta potential. They inhibited the growth of Staphylococcus aureus and did not exhibit cytotoxic activity against mammalian cells. (4) Conclusions: Encapsulation in liposomes was demonstrated to be a promising strategy for natural compounds possessing antimicrobial activity.

Lippia alba essential oil: A powerful and valuable antinociceptive and anti-inflammatory medicinal plant from Brazil.

ETHNOPHARMACOLOGICAL RELEVANCE: In Brazilian popular medicine, Lippia alba leaves are used in teas to treat pain and inflammatory diseases. AIM OF THE STUDY: to evaluate the chemical composition, antinociceptive, and anti-inflammatory activities of Lippia alba essential oil and its major compound geraniol. MATERIAL AND METHODS: Lippia alba leaves were collected in Pará state, Brazil. The leaf essential oil was obtained using a modified Clevenger-type extractor. Then, the oil was analyzed by GC and GC-MS analyses. To evaluate the toxicity of LaEO and geraniol, the doses of 50, 300, and 2000 mg/kg were used in a mouse model. For antinociception tests, abdominal contortion, hot plate, and formalin tests were used; all groups were treated with LaEO and geraniol at doses of 25, 50, and 100 mg/kg; and to evaluate inflammation using the ear edema model. RESULTS: The constituents identified in the highest content were oxygenated monoterpenes: geraniol (37.5%), geranial (6.7%) and neral (3.8%). The animals treated with LaEO and geraniol demonstrated atypical behaviors with aspects of lethargy and drowsiness, characteristics of animals in a state of sedation; the relative weights showed no significant difference compared to the controls. In the abdominal contortion test, LaEO at 25 mg/kg, 50 mg/kg doses, and 100 mg/kg reduced the number of contortions, representing a percentage reduction of 84.64%, 81.23%, and 66.21% respectively. In the hot plate test, LaEO and geraniol increased the latency time at doses of 25, 50, and 100 mg/kg in all test periods; there was no statistical difference between LaEO and geraniol. In the first phase of the formalin test, only doses of 25 mg/kg and 100 mg/kg of LaEO showed significant activity, reducing the latency time by 53.40% and 58.90%. LaEO at doses of 25 mg/kg and 100 mg/kg reduced the size of the edema, demonstrating an anti-inflammatory activity of 59.38% (25 mg/kg) and 50% (100 mg/kg). CONCLUSION: Lippia alba essential oil and geraniol showed central/peripheral analgesic and anti-inflammatory potential and can be used as an alternative or complementary treatment to conventional drugs. More studies are needed to evaluate its action mechanisms and its analgesic effects.

Antifungal properties and molecular docking of ZnO NPs mediated using medicinal plant extracts.

Significant postharvest losses and food safety issues persist in many developing nations, primarily due to fungal activities, including mycotoxin production. In this study, green synthesised zinc oxide nanoparticles (ZnO-NPs) were prepared from leaf extracts of Syzygium cordatum (ZnO 1), Lippia javanica (ZnO 2), Bidens pilosa (ZnO 3), and Ximenia caffra (ZnO 4). Physicochemical characteristics of the ZnO-NPs were determined using X-ray diffraction (XRD), Fourier transmission Infrared spectroscopy and ultraviolet-visible (UV-vis) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD analysis confirmed the presence of a wurtzite crystal structure in the hexagonal shape of the ZnO nanoparticles (NPs), with an average size ranging between 25 and 43 nm. The microscopic examination of the morphology revealed the presence of spherical particles with sizes ranging from 37 to 47 nm in diameter. The antifungal efficacy of the ZnO-NPs was assessed against pathogenic plant fungi, including Botrytis sp. (STEU 7866), Penicillium sp. (STEU 7865), and Pilidiella granati (STEU 7864), using the poisoned food technique. Further antifungal evaluation of the ZnOPs was performed using the broth microdilution assay. A significant interaction between the type of ZnO-NPs and fungal species was observed, with the highest susceptibility in Mucor sp. to ZnO 2, achieving over 50% inhibition. Penicillium sp. also showed high susceptibility to all ZnO-NPs. Molecular docking results confirmed the strong H-bonding interactions of ZnO-NPs with fungal receptors in Mucor sp. and Penicillium sp., Botrytis sp. and P. granati exhibited the least susceptibility. Further tests revealed that ZnO 2 exhibited the highest inhibitory effect on Botrytis sp., with a low minimum inhibitory concentration (MIC) of 25 µg/mL, attributed to its larger positive zeta potential. This study indicates that ZnO NPs, particularly those mediated using Lippia javanica (ZnO 2), have promising potential as effective antifungal agents, which could play a significant role in reducing postharvest decay and losses.

Screening of essential oils against oxacillin - resistant Staphylococcus aureus strains isolated from bovine mastitis / Screening de aceites esenciales frente a Staphylococcus aureus oxacilino - resistentes extraidos de aislados de mastitis bovina

Bovine mastitis is a disease wi th far - reaching consequences for the dairy industry. Staphylococcus aureus is a pathogen that is especially resistant to antibiotics. The objective of this study was to evaluate the antimicrobial activity of the essential oils Lippia citriodora (Lam.), Thy mus vulgaris (L), and a mixture of the essential oils Lippia citriodora and Thymus vulgaris (50/50 v/v), against isolates of oxacillin - resistant Staphylococcus aureus (n=15) of positive cases of bovine mastitis. For the statistical analysis, the IBM SPSS s tatistical package was used. The mixture of essential oils ( Lippia citriodora and Thymus vulgaris (50/50 v/v)) obtained the most significant antimicrobial activity in relation to pure essential oils. It is therefore concluded that the mixture of these oils boosts their antimicrobial activity ( p <0.05). The minimum inhibitory and bactericidal concentration of this mixture for the total isolations was 12 µL/L and 25 µL/mL, respectively.

La mastitis bovina es una enfermedad de gran impacto para la industria lechera. El Staphylococcus aureus es uno de los principales patógenos, especialmente aquellos resistentes a los antibióticos. El objetivo de este estudio fue evaluar la actividad antimicrobiana de los aceites esenciales de Lippia citriodora (Lam.), Thymus vulgaris (L), y una mezcla de aceites esenciales de Lippia citriodora y Thymus vulgaris (50/50 v/v), frente a aislamientos clínicos de Staph ylococcus aureus oxacilino - resistentes (n=15) de mastitis bovina. Se utilizó p rograma estadístico IBM SPSS y se concluyó la diferencia significativa a un p <0.05. La mezcla de aceites esenciales ( Lippia citriodora y Thymus vulgaris (50/50 v/v)), obtuvo la m ayor actividad antimicrobiana en relación a los aceites esenciales puros, se concluye que la mezcla de estos aceites potencia su actividad antimicrobiana ( p <0.019). La concentración mínima inhibitoria y bactericida de esta mezcla fue del 12 µL/mL y 25 µL/m L, respectivamente, y puede ser una alternativa terapéutica.

Comportamiento fenológico ex situ de Lippia integrifolia "incayuyo" (Verbenaceae) de una población de base genética amplia / Ex situ phenological behavior of Lippia integrifolia "incayuyo" (Verbenaceae) from a population with a broad genetic base

Abstract: Lippia integrifolia "incayuyo" is an aromatic, sub - woody shrub used in popular medicine, aperitit drinks and compound herb s. Its choleretic, antispasmodic, biocidal, antibacterial and larvicidal activity has been proven. The objective of the work was to register the phenology of a sample of 70 genotypes from a population with a broad genetic base. The phenophases studied were : vegetative growth, flower bud, flowering and fruiting fortnightly for two years. The initiation, intensity and prolongation of the phenophases were evaluated. The moment of full bloom occurs during the second half of December. Taking this date as a refer ence, a differentiated beginning of flowering was evidenced. The results of two campaigns were compared, observing that 70% of the specimens had a similar behavor, standing out some genotypes for presenting an early flowering and longer duration. The recor ded variability suggests that much of it could be due to intrinsic factors of the plant, and therefore, feasible to be selected .

Resumen: Lippia integrifolia "incayuyo" es un arbusto aromático, subleñoso empleado en la medicina popular, bebidas aperitivas y yerbas compuestas. Se ha comprobado su actividad colerética, antiespasmódica, biocida, antibacteriana y larvicida. El objetivo del trabajo fue registrar la fenología d e una muestra de 70 genotipos de una población de base genética amplia. Las fenofases estudiadas fueron: crecimiento vegetativo, botón floral, floración y fructificación quincenalmente durante dos años. Se evaluó inicio, intensidad y prolongación de las fe nofases. El momento de plena floración ocurre durante la segunda quincena de diciembre. Tomando esta fecha como referencia, se evidenció un inicio de floración diferenciada. Se compararon los resultados de dos campañas, observando que el 70% de los ejempla res tuvo un compartimiento semejante, destacándose algunos genotipos por presentar una floración temprana y de prolongación superior. La variabilidad registrada sugiere que gran parte de ésta podría deberse a factores intrínsecos de la planta, y por ello, factible de ser seleccionados.

Seasonal variation of essential oil of germplasm of Lippia origanoidesKunth. (Verbenaceae) / Variación estacional de aceite esencial de germoplasma de Lippia origanoidesKunth. (Verbenaceae)

The biological activities attributed to Lippia origanoides Kunth. vary according to the chemical composition of its essential oil, which can be related to weather factors. The aim of this research was the seasonal study of the essential oil chemical composition taken from L. origanoides accessions maintained in germplasm bank in vivo. The essential oil was extracted by hydrodistillation in Clevenger apparatus and identification of the components was done by GC-MS. We have identified 15 compounds of which carvacrol, p-cymene, thymol and methyl-ether-thymol were majority throughout the year for most accessions. In three accessions showed fluctuations in the production of the major compound during the year like the α-pinene, limonene and borneol. The essential oil showed variation in chemical composition throughout the year, the major compound in most of the accessions during the year is carvacrol. In some accessions, there are alterations of the majority component.

Las actividades biológicas atribuidas a Lippia origanoides Kunth. varían según la composición química de su aceite esencial, lo que puede estar relacionado con factores climáticos. El objetivo de esta investigación fue el estudio estacional de la composición química del aceite esencial extraído de accesiones de L. origanoides mantenidas en banco de germoplasma in vivo. El aceite esencial se extrajo mediante hidrodestilación en un aparato Clevenger y la identificación de los componentes se realizó mediante GC-MS. Hemos identificado 15 compuestos de los cuales carvacrol, p-cimeno, timol y metil-éter-timol fueron mayoritarios durante todo el año para la mayoría de las accesiones. En tres accesiones se observaron fluctuaciones en la producción del compuesto principal durante el año como el α-pineno, limoneno y borneol. El aceite esencial mostró variación en la composición química a lo largo del año, el compuesto principal en la mayoría de las accesiones durante el año es el carvacrol. En algunas accesiones, hay alteraciones del componente mayoritario.

Cytotoxic activity of ethanolic extracts of Lippia graveolens HBK leaves and stem against lung cancer cell line SK-LU-1 / Actividad citotóxica de extractos etanólicos de hoja y tallos de Lippia graveolens HBK contra la línea celular de cáncer de pulmón SK-LU-1

Lippia graveolens HBK (Verbenaceae) is an aromatic herb of economic importance in Mexico, known as oregano. The leaves are used as condiments, and people use this species for respiratory and digestive disorders. The aim of this work was to evaluate the cytotoxic effect of ethanolic extracts obtained from free-oil leaves (L9) and stem (S15), against lung cancer cell line SK-LU-1, through tetrazolium salt (MTT) assay. Extracts concentrations of 0.3 to 300 µg/mL were used and HFF-1 as normal control cells. Both L9 and S15 extracts, showed cytotoxic effect, although stem was stronger than leaves and without damage to normal cell control. The phenolic compounds caffeic acid and acacetin werein higher concentration in L9, whereas naringenin, taxifolin, eriodictyol, luteolin, and apigenin had higher concentrations in S15. The ethanolic extracts of L. graveolens have excellent cytotoxic activity, and have a wide possibility of use in lung cancer treatment.

Lippia graveolens HBK. (Verbenaceae) es una hierba aromática de importancia económica en México, conocida como orégano. Las hojas se usan como condimento y en medicina tradicional se utiliza para aliviar malestares respiratorios y digestivos. El objetivo de este trabajo fue evaluar el efecto citotóxico de extractos etanólicos obtenidos de hojas sin aceite (L9) y tallo (S15), sobre la línea celular de cáncer de pulmón SK-LU-1, mediante el ensayo de la sal de tetrazolium (MTT). Los extractos se aplicaron a concentraciones de 0,3 a 300 µg/mL y se utilizaron células HFF-1 como control normal. Tanto los extractos L9 como S15 mostraron efecto citotóxico, aunque el efecto del tallo fue mayor al de las hojas y sin daño al control celular normal. Los compuestos fenólicos ácido cafeico y acacetina se encontraron en mayor concentración en L9, mientras que naringenina, taxifolina, eriodictyol, luteolina y apigenina tuvieron mayor concentración en S15. Los extractos etanólicos de L. graveolens tienen una excelente actividad citotóxica, con amplia posibilidad de utilizar en el tratamiento de cáncer de pulmón.