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-β-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.

Antioxidant Properties and Secondary Metabolites Profile of Hyptis colombiana at Various Phenological Stages

Hyptis colombiana (Lamiaceae family), a species also treated as Cantinoa colombiana in a recently segregated genus from Hyptis, is a perennial herb or subshrub native to the Andes of northern South America. H. colombiana leaves are commonly used in traditional medicine to treat respiratory and digestive illnesses. In this study, H. colombiana plants at different phenological stages (vegetative, flowering, and post-flowering) were harvested to obtain essential oils (EOs) and extracts (from fresh plant materials or post-distillation waste) whose chemical compositions and antioxidant activities were determined. H. colombiana EOs distilled by microwave-assisted hydrodistillation were analyzed by GC/MS/FID, and hydroalcoholic extracts obtained from fresh plant materials or post-distillation waste were analyzed by UHPLC-ESI+/--Orbitrap-MS. The antioxidant activity was evaluated by the ABTS+• and ORAC assays. The principal compounds found in EOs were sesquiterpene hydrocarbons (65%); specifically, (E)-β-caryophyllene and germacrene D. Pyranone, rosmarinic acid, rutin, and p-hydroxybenzoic acid were the main constituents in H. colombiana extracts. After analyzing the chemical composition and antioxidant activity (ORAC) of EOs and hydroethanolic extracts from flowering H. colombiana plants, minimal variations were found. It is advisable to harvest H. colombiana plants during their flowering stage to acquire EOs and extracts that can be utilized in the agro-industry of EOs and their natural derivatives.

Enhanced Two-Step Extraction from Biomass of Two Cymbopogon Species Cultivated in Santander, Colombia

The insertion of circular economy principles into the essential oil (EO) production chain aims to reduce waste generation and make integral use of harvested plant material. Higher profits from integral use with reduced waste generation contribute to the eventual use of the EO value chain as an alternative to illicit crops in Colombia (mostly coca). In this study, Java-type citronella (Cymbopogon winterianus) and palmarosa (C. martinii) plant materials were used in two consecutive processes to obtain EOs and extracts. The residual biomass after EO distillation was subjected to ultrasound-assisted hydroethanolic extraction to afford extracts that contained bioactive compounds. Citronella and palmarosa were distilled with typical EO yields (1.0 ± 0.1% for citronella; 0.41 ± 0.06% for palmarosa; n = 5) either through hydrodistillation assisted by microwave radiation or through steam distillation, and their composition (determined via GC/FID/MS analysis) and physicochemical parameters fell within their ISO standard specifications. The concentration of citronellal, the major compound of citronella oil, was 500 ± 152 mg/g. Geraniol, the main component of palmarosa oil, was found at 900 ± 55 mg/g. The citronella and palmarosa hydroalcoholic extracts (4-11% yield) were analyzed with UHPLC-ESI-Orbitrap-MS, which permitted the identification of 30 compounds, mainly C-glycosylated flavones and hydroxycinnamic acids. Both extracts had similar antioxidant activity values, evaluated using the ABTS+● and ORAC assays (110 ± 44 µmol Trolox®/g extract and 1300 ± 141 µmol Trolox®/g extract, respectively).

Exploring the Potential of Extracts from Sloanea medusula and S. calva: Formulating Two Skincare Gels with Antioxidant, Sun Protective Factor, and Anti-Candida albicans Activities

Sloanea is a plant genus, native to tropical regions, used in medicinal practices for its anti-inflammatory properties. This study aimed to determine the antioxidant activity, sun protective factor (SPF), and antifungal of extracts obtained from two species of Sloanea and to develop extract-based gels with antioxidants, photoprotective, and anti-Candida albicans effects. Ethanolic extracts from S. medusula and S. calva collected in Chocó, Colombia, were used for antioxidant activity and SPF determination using the DPPH assay and the Mansur equation, respectively. Extracts were characterized using HPLC-MS and used to prepare the gels. The viscosity of the extract-based gels was evaluated using an MCR92 rheometer. In addition, the anti-Candida activity of extracts against five yeasts and anti-C. albicans of gels were evaluated following the Clinical and Laboratory Standards Institute M27, 4th Edition. High DPPH radical scavenging activity (42.4% and 44.7%) and a high SPF value (32.5 and 35.4) were obtained for the extracts of S. medusula and S. calva, respectively. Similarly, extract-based gels showed significant DPPH radical scavenging activity of 54.5% and 53.0% and maximum SPF values of 60 and 57. Extract from S. medusula showed an important antifungal activity against C. albicans (minimal inhibitory concentration (MIC) of 2 µg/mL). In contrast, S. calva extract was active against C. krusei, C. albicans (MIC of 2 µg/mL) and C. tropicalis (MIC of 4 µg/mL). Sloanea medusula gel (0.15%) exhibited an important C. albicans growth inhibition (98%), while with S. calva gel (0.3%) growth inhibition was slightly lower (76%). Polyphenolic and triterpenoid compounds were tentatively identified for S. medusula and S. calva, respectively. Both extracts can be considered promising sources for developing photoprotective gels to treat skin infections caused by C. albicans.

Citral-rich fractions of Lippia alba essential oils as immunoresponsive and anti-Candida albicans additives for collagen membranes in guided bone regeneration

PURPOSE

The aim of this study was to optimize the immunoresponsive and anti-Candida albicans (C. albicans) properties of guided bone regeneration-resorbable membranes (collagen) using additives based on synergistic mixtures of chlorhexidine with terpene-enriched fractions from Lippia alba essential oils (EO).

METHODS

The anti-C. albicans activity of the fractions (individually or combined with chlorhexidine) was evaluated using planktonic and sessile cultures. J774A.1 murine macrophage cells were used to determine the cytotoxicity and immunoresponsive effects of the therapies.

RESULTS

The anti-planktonic and anti-sessile performance of chlorhexidine on C. albicans was improved 2- to 4-fold by supplementation with citral-rich fractions. On macrophages, this fraction also exhibited a potentially cytoprotective action against the toxic effects of chlorhexidine, minimizing damage to the cell membrane, mitochondrial membrane potential, and nuclear integrity. Macrophages growing on collagen-membrane fragments and stimulated with the citral fraction (alone or with chlorhexidine) showed a significant increase in releasing the osteogenic cytokine TNF-α and enhancing the IL-4.

CONCLUSION

This combined therapy appears as a promising platform for the development of a prophylactic or therapeutic biocidal solution that can optimize the pharmacological characteristics of chlorhexidine (epithelium tolerance and anti-C. albicans consolidation on surfaces), as well as potentiating the immunoresponsive properties of collagen membranes.

Comparative Virucidal Activities of Essential Oils and Alcohol-Based Solutions against Enveloped Virus Surrogates: In Vitro and In Silico Analyses

The large-scale use of alcohol (OH)-based disinfectants to control pathogenic viruses is of great concern because of their side effects on humans and harmful impact on the environment. There is an urgent need to develop safe and environmentally friendly disinfectants. Essential oils (EOs) are generally recognized as safe (GRAS) by the FDA, and many exhibit strong antiviral efficacy against pathogenic human enveloped viruses. The present study investigated the virucidal disinfectant activity of solutions containing EO and OH against DENV-2 and CHIKV, which were used as surrogate viruses for human pathogenic enveloped viruses. The quantitative suspension test was used. A solution containing 12% EO + 10% OH reduced > 4.0 log10 TCID₅₀ (100% reduction) of both viruses within 1 min of exposure. In addition, solutions containing 12% EO and 3% EO without OH reduced > 4.0 log10 TCID₅₀ of both viruses after 10 min and 30 min of exposure, respectively. The binding affinities of 42 EO compounds and viral envelope proteins were investigated through docking analyses. Sesquiterpene showed the highest binding affinities (from -6.7 to -8.0 kcal/mol) with DENV-2 E and CHIKV E1-E2-E3 proteins. The data provide a first step toward defining the potential of EOs as disinfectants.

Chemical Composition and In Vitro Antioxidant Activity of Salvia aratocensis (Lamiaceae) Essential Oils and Extracts

Salvia aratocensis (Lamiaceae) is an endemic shrub from the Chicamocha River Canyon in Santander (Colombia). Its essential oil (EO) was distilled from the aerial parts of the plant via steam distillation and microwave-assisted hydrodistillation and analyzed using GC/MS and GC/FID. Hydroethanolic extracts were isolated from dry plants before distillation and from the residual plant material after distillation. The extracts were characterized via UHPLC-ESI^(+/-)-Orbitrap-HRMS. The S. aratocensis essential oil was rich in oxygenated sesquiterpenes (60-69%) and presented τ-cadinol (44-48%) and 1,10-di-epi-cubenol (21-24%) as its major components. The in vitro antioxidant activity of the EOs, measured via an ABTS^+• assay, was 32-49 μmol Trolox^® g^-1 and that measured using the ORAC assay was 1520-1610 μmol Trolox^® g^-1. Ursolic acid (28.9-39.8 mg g^-1) and luteolin-7-O-glucuronide (1.16-25.3 mg g^-1) were the major S. aratocensis extract constituents. The antioxidant activity of the S. aratocensis extract, obtained from undistilled plant material, was higher (82 ± 4 μmol Trolox^® g^-1, ABTS^+•; 1300 ± 14 μmol Trolox^® g^-1, ORAC) than that of the extracts obtained from the residual plant material (51-73 μmol Trolox^® g^-1, ABTS^+•; 752-1205 μmol Trolox^® g^-1, ORAC). S. aratocensis EO and extract had higher ORAC antioxidant capacity than the reference substances butyl hydroxy toluene (98 μmol Trolox^® g^-1) and α-tocopherol (450 μmol Trolox^® g^-1). S. aratocensis EOs and extracts have the potential to be used as natural antioxidants for cosmetics and pharmaceutical products.

Untargeted Metabolomics for Unraveling the Metabolic Changes in Planktonic and Sessile Cells of Salmonella Enteritidis ATCC 13076 after Treatment with Lippia origanoides Essential Oil

Nontyphoidal Salmonella species are one of the main bacterial causes of foodborne diseases, causing a public health problem. In addition, the ability to form biofilms, multiresistance to traditional drugs, and the absence of effective therapies against these microorganisms are some of the principal reasons for the increase in bacterial diseases. In this study, the anti-biofilm activity of twenty essential oils (EOs) on Salmonella enterica serovar Enteritidis ATCC 13076 was evaluated, as well as the metabolic changes caused by Lippia origanoides thymol chemotype EO (LOT-II) on planktonic and sessile cells. The anti-biofilm effect was evaluated by the crystal violet staining method, and cell viability was evaluated through the XTT method. The effect of EOs was observed by scanning electron microscopy (SEM) analysis. Untargeted metabolomics analyses were conducted to determine the effect of LOT-II EO on the cellular metabolome. LOT-II EO inhibited S. Enteritidis biofilm formation by more than 60%, without decreasing metabolic activity. Metabolic profile analysis identified changes in the modulation of metabolites in planktonic and sessile cells after LOT-II EO treatment. These changes showed alterations in different metabolic pathways, mainly in central carbon metabolism and nucleotide and amino acid metabolism. Finally, the possible mechanism of action of L. origanoides EO is proposed based on a metabolomics approach. Further studies are required to advance at the molecular level on the cellular targets affected by EOs, which are promising natural products for developing new therapeutic agents against Salmonella sp. strains.

Effect of Essential Oil from Lippia origanoides on the Transcriptional Expression of Genes Related to Quorum Sensing, Biofilm Formation, and Virulence of Escherichia coli and Staphylococcus aureus

Microbial infections resistant to conventional antibiotics constitute one of the most important causes of mortality in the world. In some bacterial species, such as Escherichia coli and Staphylococcus aureus pathogens, biofilm formation can favor their antimicrobial resistance. These biofilm-forming bacteria produce a compact and protective matrix, allowing their adherence and colonization to different surfaces, and contributing to resistance, recurrence, and chronicity of the infections. Therefore, different therapeutic alternatives have been investigated to interrupt both cellular communication routes and biofilm formation. Among these, essential oils (EO) from Lippia origanoides thymol-carvacrol II chemotype (LOTC II) plants have demonstrated biological activity against different biofilm-forming pathogenic bacteria. In this work, we determined the effect of LOTC II EO on the expression of genes associated with quorum sensing (QS) communication, biofilm formation, and virulence of E. coli ATCC 25922 and S. aureus ATCC 29213. This EO was found to have high efficacy against biofilm formation, decreasing-by negative regulation-the expression of genes involved in motility (fimH), adherence and cellular aggregation (csgD), and exopolysaccharide production (pgaC) in E. coli. In addition, this effect was also determined in S. aureus where the L. origanoides EO diminished the expression of genes involved in QS communication (agrA), production of exopolysaccharides by PIA/PNG (icaA), synthesis of alpha hemolysin (hla), transcriptional regulators of the production of extracellular toxins (RNA III), QS and biofilm formation transcriptional regulators (sarA) and global regulators of biofilm formation (rbf and aur). Positive regulation was observed on the expression of genes encoding inhibitors of biofilm formation (e.g., sdiA and ariR). These findings suggest that LOTCII EO can affect biological pathways associated with QS communication, biofilm formation, and virulence of E. coli and S. aureus at subinhibitory concentrations and could be a promising candidate as a natural antibacterial alternative to conventional antibiotics.

Metabolomic Analysis of the Effect of Lippia origanoides Essential Oil on the Inhibition of Quorum Sensing in Chromobacterium violaceum

Bacteria can communicate through quorum sensing, allowing them to develop different survival or virulence traits that lead to increased bacterial resistance against conventional antibiotic therapy. Here, fifteen essential oils (EOs) were investigated for their antimicrobial and anti-quorum-sensing activities using Chromobacterium violaceum CV026 as a model. All EOs were isolated from plant material via hydrodistillation and analyzed using GC/MS. In vitro antimicrobial activity was determined using the microdilution technique. Subinhibitory concentrations were used to determine anti-quorum-sensing activity by inhibition of violacein production. Finally, a possible mechanism of action for most bioactive EOs was determined using a metabolomic approach. Among the EOs evaluated, the EO from Lippia origanoides exhibited antimicrobial and anti-quorum activities at 0.37 and 0.15 mg/mL, respectively. Based on the experimental results, the antibiofilm activity of EO can be attributed to the blockage of tryptophan metabolism in the metabolic pathway of violacein synthesis. The metabolomic analyses made it possible to see effects mainly at the levels of tryptophan metabolism, nucleotide biosynthesis, arginine metabolism and vitamin biosynthesis. This allows us to highlight the EO of L. origanoides as a promising candidate for further studies in the design of antimicrobial compounds against bacterial resistance.

Chemical Characterization and Determination of the Antioxidant Properties of Phenolic Compounds in Three Scutellaria sp. Plants Grown in Colombia

Plants of the genus Scutellaria (Lamiaceae) have a wide variety of bioactive secondary metabolites with diverse biological properties, e.g., anti-inflammatory, antiallergenic, antioxidant, antiviral, and antitumor activities. The chemical composition of the hydroethanolic extracts, obtained from dried plants of S. incarnata, S. coccinea, and S. ventenatii × S. incarnata, was determined by UHPLC/ESI-Q-Orbitrap-MS. The flavones were found in a higher proportion. Baicalin and dihydrobaicalein-glucuronide were the major extract components in S. incarnata (287.127 ± 0.005 mg/g and 140.18 ± 0.07 mg/g), in S. coccinea (158.3 ± 0.34 mg/g and 51.20 ± 0.02 mg/g), and in S. ventenatii × S. incarnata (186.87 ± 0.01 mg/g and 44.89 ± 0.06 mg/g). The S. coccinea extract showed the highest antioxidant activity in the four complementary techniques employed to evaluate all extracts: ORAC (3828 ± 3.0 µmol Trolox^®/g extract), ABTS^+• (747 ± 1.8 µmol Trolox^®/g extract), online HPLC-ABTS^+• (910 ± 1.3 µmol Trolox^®/g extract), and β-carotene (74.3 ± 0.8 µmol Trolox^®/g extract).

Deleterious Effects of Cymbopogon nardus (L.) Essential Oil on Life Cycle and Midgut of the Natural Predator Ceraeochrysa claveri (Navás, 1911) (Neuroptera: Chrysopidae)

Cymbopogon nardus (citronella) essential oil (EO) has been widely used in the cosmetic and food industry due to its repellent and fumigant properties. The aim of this study was to evaluate its effects on the life cycle and midgut morphology of the natural predator Ceraeochrysa claveri. Larvae were fed on sugarcane borer eggs (Diatraea saccharalis) pretreated with citronella EO solutions (1-100 µg/mL in methanol, 5 s) or solvent and air-dried at room temperature for 30 min. Larval and pupal stage duration, the percentage of emergence of the insect, and malformed insects were recorded. One day after adults emerged from their cocoons, adult insects were used to obtain their midgut and analyzed using light microscopy. The chemical composition of C. nardus EO revealed that citronellal (25.3%), citronellol (17.9%), geraniol (11.6%), elemol (6.5%), δ-cadinone (3.6%), and germacrene D (3.4%) were the predominant compounds. Exposure to the EO produced a significant change in development duration for third instar and prepupa of the insect. The observed alterations in the lifecycle included prepupae with no cocoon formation, dead pupa inside the cocoon, and malformed adults. Several injuries in the midgut epithelium of exposed adults were registered, such as detachment of columnar cells leaving only swollen regenerative cells fixed on the basement membrane, and the formation of epithelial folds. In summary, these data suggest that C. nardus oil has adverse effects on the life cycle and midgut morphology of a beneficial predator.

Antifungal and Antibiofilm Activity of Colombian Essential Oils against Different Candida Strains

Most Candida species are opportunistic pathogens with the ability to form biofilms, which increases their resistance to antifungal drug therapies and the host immune response. Essential oils (EOs) are an alternative for developing new antimicrobial drugs, due to their broad effect on cellular viability, cell communication, and metabolism. In this work, we evaluated the antifungal and antibiofilm potential of fifty EOs on C. albicans ATCC 10231, C. parapsilosis ATCC 22019, and Candida auris CDC B11903. The EOs’ antifungal activity was measured by means of a broth microdilution technique to determine the minimum inhibitory and fungicidal concentrations (MICs/MFCs) against the different Candida spp. strains. The effects on biofilm formation were determined by a crystal violet assay using 96-well round-bottom microplates incubated for 48 h at 35 °C. The EOs from Lippia alba (Verbenaceae family) carvone-limonene chemotype and L. origanoides exhibited the highest antifungal activity against C. auris. The L. origanoides EOs also presented antifungal and antibiofilm activity against all three Candida spp., thus representing a promising alternative for developing new antifungal products focused on yeast infections, especially those related to biofilm formation, virulence factors, and antimicrobial resistance.

Essential Oils Distilled from Colombian Aromatic Plants and Their Constituents as Penetration Enhancers for Transdermal Drug Delivery

The study aimed to determine the enhanced effects of essential oils (EOs) and plant-derived molecules (PDMs) as penetration enhancers (PEs) for transdermal drug delivery (TDD) of caffeine. A 1% w/w solution of eight EOs and seven PDMs was included in the 1% caffeine carbopol hydrogel. Franz diffusion cell experiments were performed using mice with full-thickness skin. At various times over 24 h, 300 μL of the receptor were withdrawn and replaced with fresh medium. Caffeine was analyzed spectrophotometrically at 272 nm. The skin irritation effects of the hydrogels applied once a day for 21 days were investigated in mice. The steady-state flux (J_SS) of the caffeine hydrogel was 30 ± 19.6 µg cm^-2 h^-1. An increase in caffeine J_SS was induced by Lippia origanoides > Turnera diffusa > eugenol > carvacrol > limonene, with values of 150 ± 14.1, 130 ± 47.6, 101 ± 21.7, 90 ± 18.4, and 86 ± 21.0 µg cm^-2 h^-1, respectively. The Kp of caffeine was 2.8 ± 0.26 cm h^-1, almost 2-4 times lower than that induced by Lippia origanoides > Turnera diffusa > limonene > eugenol > carvacrol, with Kp values of 11 ± 1.7, 8.8 ± 4.2, 6.8 ± 1.7, 6.3 ± 1.2, and 5.15 ± 1.0 cm h^-1, respectively. No irritating effects were observed. Lippia origanoides, Turnera diffusa, eugenol, carvacrol, and limonene improved caffeine's skin permeation. These compounds may be as effective as the PE in TDD systems.

Insecticidal activity of essential oils from American native plants against Aedes aegypti (Diptera: Culicidae): an introduction to their possible mechanism of action

Searching for new bioactive molecules to design insecticides is a complex process since pesticides should be highly selective, active against the vector, and bio-safe for humans. Aiming to find natural compounds for mosquito control, we evaluated the insecticidal activity of essential oils (EOs) from 20 American native plants against Aedes aegypti larvae using bioassay, biochemical, and in silico analyses. The highest larvicide activity was exhibited by EOs from Steiractinia aspera (LC₅₀ = 42.4 µg/mL), Turnera diffusa (LC₅₀ = 70.9 µg/mL), Piper aduncum (LC₅₀ = 55.8 µg/mL), Lippia origanoides (chemotype thymol/carvacrol) (LC₅₀ = 61.9 µg/mL), L. origanoides (chemotype carvacrol/thymol) (LC₅₀ = 59.8 µg/mL), Hyptis dilatata (LC₅₀ = 61.1 µg/mL), Elaphandra quinquenervis (LC₅₀ = 61.1 µg/mL), and Calycolpus moritzianus (LC₅₀ = 73.29 µg/mL) after 24 h. This biological activity may be related to the disruption of the electron transport chain through the mitochondrial protein complexes. We hypothesized that the observed EOs' effect is due to their major components, where computational approaches such as homology modeling and molecular docking may suggest the possible binding pose of secondary metabolites that inhibit the mitochondrial enzymes and acetylcholinesterase activity (AChE). Our results provided insights into the possible mechanism of action of EOs and their major compounds for new insecticide designs targeting the mitochondria and AChE activity in A. aegypti for effective and safe insecticide.

Chemical Composition, Repellent Action, and Toxicity of Essential Oils from Lippia origanoide, Lippia. alba Chemotypes, and Pogostemon cablin on Adults of Ulomoides dermestoides (Coleoptera: Tenebrionidae)

The essential oils (EOs) from bioactive species can provide an alternative tool for the management of stored grain insects that is less environmentally damaging than synthetic chemicals. The aim of this study was to assess the repellent action and toxicity of EOs obtained from phellandrene-rich Lippia origanoides, carvone-rich Lippia alba, citral-rich L. alba, and Pogostemon cablin aerial parts on adults of Ulomoides dermestoides. These EOs were isolated by hydrodistillation and characterized by gas chromatography coupled to mass spectrometry (GC-MS). The repellency assay was carried out using the area preference method, and the toxicity evaluated utilizing a filter paper contact test. The major components (>10%) of the studied EOs were sabinene (16.9%), trans-β-caryophyllene (18.6%) and α-humulene (10.1%) for phellandrene-rich L. origanoides EO; limonene (40.1%) and carvone (37.7%) for carvone-rich L. alba EO; geranial (24.5%), geraniol (19.0%), and neral (11.9%) for citral-rich L. alba EO; and α-guaiene (13.3%), α-bulnesene (15.7%), and patchoulol (35.3%) for P. cablin EO. All EOs displayed 100% repellency at a concentration of 16 μL/mL, with lower toxicity than that elicited by the commercial repellent DEET. EO concentrations up to 8 µL/mL did not induce any mortality on the beetle. These findings show that the EOs provide active and safe molecules for natural repellent formulations to prevent and control insect infestations of stored products.

Essential Oil of Carvone Chemotype Lippia alba (Verbenaceae) Regulates Lipid Mobilization and Adipogenesis in Adipocytes

Obesity is characterized by an expansion of adipose tissue due to excessive accumulation of triglycerides in adipocytes, causing hypertrophy and hyperplasia, followed by hypoxia, alterations in adipocyte functionality, and chronic inflammation. However, current treatments require changes in lifestyle that are difficult to achieve and some treatments do not generate sustained weight loss over time. Therefore, we evaluated the effect of the essential oil (EO) of Lippia alba (Verbenaceae) carvone chemotype on viability, lipid mobilization, and adipogenesis of adipocytes in two normal and pathological cellular models in vitro. In 3T3-L1 adipocytes, a normal and a pathological model of obesity were induced, and then the cells were treated with L. alba carvone chemotype EO to evaluate cell viability, lipid mobilization, and adipogenesis. L. alba carvone chemotype EO does not decrease adipocyte viability at concentrations of 0.1, 1, and 5 µg/mL; furthermore, there was evidence of changes in lipid mobilization and adipogenesis, leading to a reversal of adipocyte hypertrophy. These results could be due to effects produced by EO on lipogenic and lipolytic pathways, as well as modifications in the expression of adipogenesis genes. L. alba carvone chemotype EO could be considered as a possible treatment for obesity, using the adipocyte as a therapeutic target.

In Vitro Activity of Essential Oils Distilled from Colombian Plants against Candidaauris and Other Candida Species with Different Antifungal Susceptibility Profiles

Multi-drug resistant species such as Candida auris are a global health threat. This scenario has highlighted the need to search for antifungal alternatives. Essential oils (EOs), or some of their major compounds, could be a source of new antifungal molecules. The aim of this study was to evaluate the in vitro activity of EOs and some terpenes against C. auris and other Candida spp. The eleven EOs evaluated were obtained by hydro-distillation from different Colombian plants and the terpenes were purchased. EO chemical compositions were obtained by gas chromatography/mass spectrometry (GC/MS). Antifungal activity was evaluated following the CLSI standard M27, 4th Edition. Cytotoxicity was tested on the HaCaT cell line and fungal growth kinetics were tested by time–kill assays. Candida spp. showed different susceptibility to antifungals and the activity of EOs and terpenes was strain-dependent. The Lippia origanoides (thymol + p-cymene) chemotype EO, thymol, carvacrol, and limonene were the most active, mainly against drug-resistant strains. The most active EOs and terpenes were also slightly cytotoxic on the HaCaT cells. The findings of this study suggest that some EOs and commercial terpenes can be a source for the development of new anti-Candida products and aid the identification of new antifungal targets or action mechanisms.

Genetic Instability among Hitnü People Living in Colombian Crude-Oil Exploitation Areas

Oil exploitation, drilling, transportation, and processing in refineries produces a complex mixture of chemical compounds, including polycyclic aromatic hydrocarbons (PAHs), which may affect the health of populations living in the zone of influence of mining activities (PZOI). Thus, to better understand the effects of oil exploitation activities on cytogenetic endpoint frequency, we conducted a biomonitoring study in the Hitnü indigenous populations from eastern Colombia by using the cytokinesis micronucleus cytome assay (CBMN-cyt). PAH exposure was also measured by determine urine 1-hydroxypyrene (1-OHP) using HPLC. We also evaluated the relationship between DNA damage and 1-OHP levels in the oil exploitation area, as well as the modulating effects of community health factors, such as Chagas infection; nutritional status; and consumption of traditional hallucinogens, tobacco, and wine from traditional palms. The frequencies of the CBMN-cyt assay parameters were comparable between PZOI and Hitnü populations outside the zone of influence of mining activities (POZOI); however, a non-significant incremental trend among individuals from the PZOI for most of the DNA damage parameters was also observed. In agreement with these observations, levels of 1-OHP were also identified as a risk factor for increased MN frequency (PR = 1.20) compared to POZOI (PR = 0.7). Proximity to oil exploitation areas also constituted a risk factor for elevated frequencies of nucleoplasmic bridges (NPBs) and APOP-type cell death. Our results suggest that genetic instability and its potential effects among Hitnü individuals from PZOI and POZOI could be modulated by the combination of multiple factors, including the levels of 1-OHP in urine, malnutrition, and some traditional consumption practices.

Flower Extracts from Ornamental Plants as Sources of Sunscreen Ingredients: Determination by In Vitro Methods of Photoprotective Efficacy, Antigenotoxicity and Safety

Plants are sources of sunscreen ingredients that prevent cellular mutations involved in skin cancer and aging. This study investigated the sunscreen properties of the extracts from some ornamental plants growing in Colombia. The UV filter capability of the flower extracts obtained from Rosa centifolia L., Posoqueria latifolia (Rudge) Schult, and Ipomoea horsfalliae Hook. was examined. Photoprotection efficacies were evaluated using in vitro indices such as sun protection factor and critical wavelength. UVB antigenotoxicity estimates measured with the SOS Chromotest were also obtained. Extract cytotoxicity and genotoxicity were studied in human fibroblasts using the trypan blue exclusion and Comet assays, respectively. Major compounds of the promising flower extracts were identified by UHPLC–ESI+–Orbitrap–MS. The studied extracts showed high photoprotection efficacy and antigenotoxicity against UVB radiation, but only the P. latifolia extract showed broad-spectrum photoprotection at non-cytotoxic concentrations. The P. latifolia extract appeared to be safer for human fibroblast cells and the R. centifolia extract was shown to be moderately cytotoxic and genotoxic at the highest assayed concentrations. The I. horsfalliae extract was unequivocally cytotoxic and genotoxic. The major constituents of the promising extracts were as follows: chlorogenic acid, ecdysterone 20E, rhamnetin-rutinoside, cis-resveratrol-diglucoside, trans-resveratrol-diglucoside in P. latifolia; quercetin, quercetin-glucoside, quercetin-3-rhamnoside, kaempferol, kaempferol-3-glucoside, and kaempferol-rhamnoside in R. centifolia. The potential of the ornamental plants as sources of sunscreen ingredients was discussed.

Evaluation of Antioxidant and Cytotoxic Activity of Hydro-Ethanolic Extracts Obtained from Steiractinia aspera Cuatrec

In this work, the antioxidant activity of the hydro-ethanolic extracts of the leaves, flowers, and aerial parts of Steiractinia aspera Cuatrec, both fresh and post-distillation, was evaluated by ABTS+·, FRAP, H2O2 and DPPH assays. The cytotoxic activity was evaluated in MCF-7, MCF-10A and HT-29 cell lines. The hydro-ethanolic extracts were obtained by matrix solid-phase dispersion (MSPD) and ultrasound-assisted solvent extraction (SE). The fresh-leaf MSPD extract had the highest antioxidant activity, and the post-distillation leaf ultrasound-assisted SE extract had the highest cytotoxicity in the MCF-7 breast cancer cell line, although not selective, which was evaluated by sulforhodamine B assay. On the other hand, ROS was evaluated by flow cytometry which showed that post-distillation leaf extract is pro-oxidant. Chlorogenic acid, kaempferol-3-glucoside and quercetin were found in the fresh leaves’ extracts, according to HPLC-DAD. PLC-DAD permitted the isolation of p-coumaric acid, E-3-(4-(((E)-3-(3,4-dihydroxyphenyl) acryloyl) oxy)-3-hydroxyphenyl) acrylic acid and a diglucosylated derivative of ursolic acid, which were analyzed by 1H and 13C NMR. Our results suggest that the fresh leaf extract of Steiractinia aspera Cuatrec has potential use for antioxidant applications.

Photoprotective Agents Obtained from Aromatic Plants Grown in Colombia: Total Phenolic Content, Antioxidant Activity, and Assessment of Cytotoxic Potential in Cancer Cell Lines of Cymbopogon flexuosus L. and Tagetes lucida Cav. Essential Oils

Photoprotective agents obtained from plants provide benefits for the health of the skin. The present study aims to assess the total phenolic content (TPC) and in vitro UV-protective properties of twelve essential oils (EOs) from plants grown in Colombia and to evaluate the antioxidant and cytotoxic potential of two species identified as photoprotective potentials: Cymbopogon flexuosus and Tagetes lucida. The composition of EOs was studied by GC/MS. The cytotoxicity of both EOs was examined using an MTT assay, and an H2-DCFDA probe was employed to estimate the intracellular production of ROS in HepG2 and Calu-1 cells. Major constituents (≥10%) were neral, geranial, geranyl acetate in C. flexuosus and estragole in T. lucida. The TPC for C. flexuosus and T. lucida EOs were ≥10 mg GAE/g of byproduct. Both EOs showed photoprotective properties (SPFin vitro: 13−14), and long-wavelength UVA protection (λc > 370 nm). HepG2 and Calu-1 cells exposed to C. flexuosus exhibited antiproliferative activity (˂50%) at 125 µg/mL, while T. lucida was at 250 and 500 µg/mL. The IC50 values for C. flexuosus were 75 and 100 µg/mL in HepG2 and Calu-1 cells, respectively, whereas those for T. lucida were >250 µg/mL. These EOs achieved significant inhibitory effects (between 15.6 and 40.4%) against H2O2-induced oxidative stress. The results showed that EO compounds recognized as antioxidants could counteract the effects elicited by H2O2.

Immunomodulation and Antioxidant Activities as Possible Trypanocidal and Cardioprotective Mechanisms of Major Terpenes from Lippia alba Essential Oils in an Experimental Model of Chronic Chagas Disease

In the late phase of Trypanosoma cruzi infection, parasite persistence and an exaggerated immune response accompanied by oxidative stress play a crucial role in the genesis of Chronic Chagasic Cardiomyopathy (CCC). Current treatments (Benznidazole (BNZ) and Nifurtimox) can effect only the elimination of the parasite, but are ineffective for late stage treatment and for preventing heart damage and disease progression. In vivo trypanocidal and cardioprotective activity has been reported for Lippia alba essential oils (EOs), ascribed to their two major terpenes, limonene and caryophyllene oxide. To investigate the role of antioxidant and immunomodulatory mechanisms behind these properties, chronic-T. cruzi-infected rats were treated with oral synergistic mixtures of the aforementioned EOs. For this purpose, the EOs were optimized through limonene-enrichment fractioning and by the addition of exogenous caryophyllene oxide (LIMOX) and used alone or in combined therapy with subtherapeutic doses of BNZ (LIMOXBNZ). Clinical, toxicity, inflammatory, oxidative, and parasitological (qPCR) parameters were assessed in cardiac tissue. These therapies demonstrated meaningful antioxidant and immunomodulatory activity on markers involved in CCC pathogenesis (IFN-γ, TNF-α, IL-4, IL-10, and iNOS), which could explain their significant trypanocidal properties and their noteworthy role in preventing, and even reversing, the progression of cardiac damage in chronic Chagas disease.

Volatiles Emission by Crotalaria nitens after Insect Attack

Plants are known to increase the emission of volatile organic compounds upon the damage of phytophagous insects. However, very little is known about the composition and temporal dynamics of volatiles released by wild plants of the genus Crotalaria (Fabaceae) attacked with the specialist lepidopteran caterpillar Utetheisa ornatrix (Linnaeus) (Erebidae). In this work, the herbivore-induced plant volatiles (HIPV) emitted by Crotalaria nitens Kunth plants were isolated with solid phase micro-extraction and the conventional purge and trap technique, and their identification was carried out by GC/MS. The poly-dimethylsiloxane/divinylbenzene fiber showed higher affinity for the extraction of apolar compounds (e.g., trans-β-caryophyllene) compared to the Porapak™-Q adsorbent from the purge & trap method that extracted more polar compounds (e.g., trans-nerolidol and indole). The compounds emitted by C. nitens were mainly green leaf volatile substances, terpenoids, aromatics, and aldoximes (isobutyraldoxime and 2-methylbutyraldoxime), whose maximum emission was six hours after the attack. The attack by caterpillars significantly increased the volatile compounds emission in the C. nitens leaves compared to those subjected to mechanical damage. This result indicated that the U. ornatrix caterpillar is responsible for generating a specific response in C. nitens plants. It was demonstrated that HIPVs repelled conspecific moths from attacked plants and favored oviposition in those without damage. The results showed the importance of volatiles in plant-insect interactions, as well as the choice of appropriate extraction and analytical methods for their study.

Plants growing in Colombia as sources of active ingredients for sunscreens

INTRODUCTION

Plants can be sources of photoprotective/antigenotoxic compounds that prevent cellular mutations involved in skin cancer and aging by regulating UV-induced mutability.

PURPOSE

The study was aimed at investigating the sunscreen properties of plants growing in Colombia.

MATERIALS AND METHODS

Ultraviolet (UV) radiation-absorption capability of different plant extracts was examined. In vitro photoprotection efficacies were evaluated using in vitro indices such as sun protection factor (SPF_in vitro) and critical wavelength (λc). Pearson correlation analysis was used to examine the relationship between SPF_in vitro and complementary UVB- antigenotoxicity estimates (%GI) based on the SOS Chromotest database. The cytotoxicity in human fibroblasts was studied using the trypan blue exclusion assay. Major compounds of promising plant extracts were determined by gas chromatography coupled to mass spectrometry (GC/MS).

RESULTS

We showed that plant extracts have sunscreen properties against UVB, whereas broad-spectrum radiation protection efficacy was poor. SPF_in vitro and %GI were correlated (R = 0.71, p < .0001) for the plant extracts under study. Three extracts obtained from Achyrocline satureioides, Chromolaena pellia, and Lippia origanoides species resulted to possess high protection efficacy and relatively low cytotoxicity in human fibroblasts. These plant extracts contained major compounds such as α-pinene, trans-β-caryophyllene, γ-muurolene, γ-cadinene and caryophyllene oxide in A. Satureioides extract, trans-β-caryophyllene, caryophyllene oxide, squalene and α-amyrin in C. pellia extract, and p-cymene, carvacrol, trans-β-caryophyllene and pinocembrin in L. origanoides extract.

CONCLUSIONS

Plants growing in Colombia contain compounds that can be useful for potential sunscreens. SPF_in vitro and %GI estimates were correlated, but %GI estimates were more sensitive to detecting activity at lower plant extract concentrations. Our results supported the need to use DNA damage detection assays as a complement to photoprotection efficacy measurement.

LC/MS study of the diversity and distribution of pyrrolizidine alkaloids in Crotalaria species growing in Colombia

Hepatotoxic and genotoxic pyrrolizidine alkaloids have been involved in the acute poisoning of animals and humans. Crotalaria (Fabaceae) species contain these alkaloids. In this work, the diversity and distribution of pyrrolizidine alkaloids in roots, leaves, flowers, and seeds of Crotalaria pallida, Crotalaria maypurensis, Crotalaria retusa, Crotalaria spectabilis, Crotalaria incana, and Crotalaria nitens were studied. Matrix solid-phase dispersion and ultra-high-performance liquid chromatography coupled with Orbitrap mass spectrometry were successfully employed in pyrrolizidine alkaloids extraction and analysis, respectively. Forty-five pyrrolizidine alkaloids were detected and their identification was based on the mass spectrometry accurate mass measurement and fragmentation pattern analysis. The cyclic retronecine-type diesters monocrotaline, crotaleschenine, integerrimine, usaramine, and their N-oxides were predominantly present. Five novel alkaloids were identified for the first time in Crotalaria species, namely 14-hydroxymonocrotaline, 12-acetylcrotaleschenine, 12-acetylmonocrotaline, 12-acetylintegerrimine, and dihydrointegerrimine. Due to a lack of commercially available standards, the response factor of monocrotaline was used for quantification of pyrrolizidine alkaloids and their N-oxides. Seeds and flowers possessed higher pyrrolizidine alkaloids amounts than roots and leaves. Due to their 1,2-unsaturated pyrrolizidine alkaloids content, the ingestion of Crotalaria plant seeds or other parts through herbal products, infusions, or natural remedies is a serious health threat to humans and livestock.

Antimicrobial and Antibiofilm Activities of Essential Oils against Escherichia coli O157:H7 and Methicillin-Resistant Staphylococcus aureus (MRSA)

The emergence of multidrug resistant microorganisms represents a global challenge due to the lack of new effective antimicrobial agents. In this sense, essential oils (EOs) are an alternative to be considered because of their anti-inflammatory, antiviral, antibacterial, and antibiofilm biological activities. Therefore, multiple efforts have been made to consider the potential use of EOs in the treatment of infections which are caused by resistant microorganisms. In this study, 15 EOs of both Colombian and introduced aromatic plants were evaluated against pathogenic strains of E. coli O157:H7 and methicillin resistant Staphylococcus aureus (MRSA) in planktonic and sessile states in order to identify relevant and promising alternatives for the treatment of microbial infections. Forty different compounds were identified in the 15 EO with nine of them constituted mainly by oxygenated monoterpenes (OM). EOs from Lippia origanoides, chemotypes thymol, and carvacrol, displayed the highest antibacterial activity against E. coli O157:H7 (MIC₅₀ = 0.9 and 0.3 mg/mL, respectively) and MRSA (MIC₅₀ = 1.2 and 0.6 mg/mL, respectively). These compounds from EOs had also the highest antibiofilm activity (inhibition percentage > 70.3%). Using scanning electron microscopy (SEM), changes in the size and morphology of both bacteria were observed when they were exposed to sub-inhibitory concentrations of L. origanoides EO carvacrol chemotype. EOs from L. origanoides, thymol, and carvacrol chemotypes represented a viable alternative for the treatment of microbial infections; however, the Selectivity Index (SI ≤ 3) indicated that it was necessary to study alternatives to reduce its in vitro cytotoxicity.

Mitochondrial affectation, DNA damage and AChE inhibition induced by Salvia officinalis essential oil on Aedes aegypti larvae

The aim of this research study was to understand the mechanism of action of Salvia officinalis (Lamiaceae) essential oil (EO) on Aedes aegypti larvae. We evaluated the effect on DNA damage, acetylcholinesterase (AChE) inhibition and mitochondrial enzymatic alterations. The major components were analyzed in silico using OSIRIS and Molispiration free software. Aedes aegypti DNA was extracted from mosquito larvae between third (L3) and fourth (L4) instars to determine the DNA fragmentation or degradation at S. officinalis EO lethal concentrations (LC₁₀, LC₂₀, LC₅₀, and LC₉₀). DNA integrity was assessed in both LCs in larvae treated for 24 h and in larvae homogenized with EO; we also assessed purified DNA larvae by a densitometric analysis. The AChE inhibition was quantified in protein larvae L3-L4 following Ellman's method and the enzymatic activities related to the mitochondrial respiratory chain of mitochondrial proteins was estimated by spectrophotometry. In silico analysis of 1,8-cineol and of α-thujone, major EO components, showed that they were highly permeable in biological membranes without mutagenic risks. Alterations in the integrity of DNA were observed in larvae exposed and homogenized with S. officinalis EO. The EO induced an AChE inhibition of 37 ± 2.6% to IC₅₀. On the other hand, mitochondrial bioenergetics suggest that EO inhibits electrons entry to the respiratory chain, via Complex II. AChE activity alteration causes mortality of individuals, by blocking the insect cholinergic functions. These results indicate that EO affects the integrity of DNA, the mitochondrial respiration chain and the AChE activity.

Photoprotective and Antigenotoxic Effects of the Flavonoids Apigenin, Naringenin and Pinocembrin

This work evaluated the photoprotective and antigenotoxic effects against ultraviolet B (UVB) radiation of flavonoid compounds apigenin, naringenin and pinocembrin. The photoprotective efficacy of these compounds was estimated using in vitro photoprotection indices, and the antigenotoxicity against UVB radiation was evaluated using the SOS chromotest and an enzymatic (proteinase K/T4 endonuclease V enzyme) comet assay in UV-treated Escherichia coli and human (HEK-293) cells, respectively. Naringenin and pinocembrin showed maximum UV-absorption peak in UVC and UVB zones, while apigenin showed UV-absorption capability from UVC to UVA range. These compounds acted as UV filters reducing UV-induced genotoxicity, both in bacteria and in human cells. The enzymatic comet assay resulted highly sensitive for detection of UVB-induced DNA damage in HEK-293 cells. In this work, the photoprotective potential of these flavonoids was widely discussed.

Induction of programmed cell death in Trypanosoma cruzi by Lippia alba essential oils and their major and synergistic terpenes (citral, limonene and caryophyllene oxide)

Background

Chagas Disease caused by Trypanosoma cruzi infection, is one of the most important neglected tropical diseases (NTD), without an effective therapy for the successful parasite eradication or for the blocking of the disease’s progression, in its advanced stages. Due to their low toxicity, wide pharmacologic spectrum, and potential synergies, medicinal plants as Lippia alba, offer a promising reserve of bioactive molecules. The principal goal of this work is to characterize the inhibitory properties and cellular effects of the Citral and Carvone L. alba chemotype essential oils (EOs) and their main bioactive terpenes (and the synergies among them) on T. cruzi forms.

Methods

Twelve L. alba EOs, produced under diverse environmental conditions, were extracted by microwave assisted hydrodistillation, and chemically characterized using gas chromatography coupled mass spectrometry. Trypanocidal activity and cytotoxicity were determined for each oil, and their major compounds, on epimastigotes (Epi), trypomastigotes (Tryp), amastigotes (Amas), and Vero cells. Pharmacologic interactions were defined by a matrix of combinations among the most trypanocidal terpenes (limonene, carvone; citral and caryophyllene oxide). The treated cell phenotype was assessed by fluorescent and optic microscopy, flow cytometry, and DNA electrophoresis assays.

Results

The L. alba EOs displayed significant differences in their chemical composition and trypanocidal performance (p = 0.0001). Citral chemotype oils were more trypanocidal than Carvone EOs, with Inhibitory Concentration 50 (IC₅₀) of 14 ± 1.5 μg/mL, 22 ± 1.4 μg/mL and 74 ± 4.4 μg/mL, on Epi, Tryp and Amas, respectively. Limonene exhibited synergistic interaction with citral, caryophyllene oxide and Benznidazole (decreasing by 17 times its IC₅₀) and was the most effective and selective treatment. The cellular analysis suggested that these oils or their bioactive terpenes (citral, caryophyllene oxide and limonene) could be inducing T. cruzi cell death by an apoptotic-like mechanism.

Conclusions

EOs extracted from L. alba Citral chemotype demonstrated significant trypanocidal activity on the three forms of T. cruzi studied, and their composition and trypanocidal performance were influenced by production parameters. Citral, caryophyllene oxide, and limonene showed a possible induction of an apoptotic-like phenotype. The best selective anti-T. cruzi activity was achieved by limonene, the effects of which were also synergic with citral, caryophyllene oxide and benznidazole.

Actividad antiproliferativa de aceites esenciales de plantas cultivadas en Colombia

Colombia posee gran diversidad de plantas medicinales, pero pocas han sido objeto de investigación. En este trabajo se evaluó la actividad antiproliferativa de aceites esenciales obtenidos por hidrodestilación asistida por microondas. Se analizaron 15 muestras de 11 especies en ensayos del MTT en células cancerosas MCF-7, HeLa y HepG-2 y se incluyeron células normales humanas (HEK293) y de animales (Vero y BF16F10) para evaluar selectividad. La composición química de muestras activas se determinó por cromatografía de gases acoplada a espectrometría de masas (GC-MS). Aceites esenciales de cuatro especies mostraron actividad antiproliferativa (CI50: 50 μg/mL) en células HeLa y/o MCF-7, en el siguiente rango (índice de selectividad en paréntesis): Piper cumanense H.B.K. (4,7) > Piper subflavum var. espejuelanum C.DC (3,9) > Salvia officinalis L. (3,6) > Piper eriopodom (Miq.) C. DC. (3,1). Ninguna muestra fue activa en células HepG-2. El análisis por CG-MS identificó β-cariofileno, α-copaeno, β-pineno, α-pineno y linalol como componentes mayoritarios. Los aceites esenciales activos pueden ser punto de partida para desarrollo de medicamentos herbales para cuidado paliativo del cáncer.

Lippia origanoides extract induces cell cycle arrest and apoptosis and suppresses NF-κB signaling in triple-negative breast cancer cells

Treatments targeting hormone receptors typically fail to provide a positive clinical outcome against triple-negative breast cancers (TNBC), which lack expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (Her2/neu). Towards identifying viable treatments for aggressive breast cancer, we have tested an extract of the tropical plant Lippia origanoides (LOE) on TNBC and normal cells lines to uncover its potential anticancer effects. Treatment with LOE reduced TNBC cell viability in a dose-dependent manner to a greater extent than in normal mammary epithelial MCF10A cells. In MDA-MB-231 cells, LOE was found to halt the cell cycle in the G0/G1 phase via cyclin D1 and cIAP2 regulation, and induce apoptosis without promoting necrosis via caspase-8/-3 and PARP cleavage. Constitutive nuclear factor-κB (NF-κB) signaling has been shown to contribute to the heightened inflammatory state and survival in TNBC cells. Herein, we also provide evidence that LOE inhibits NF-κB signaling by reducing RIP1 protein levels in MDA-MB-231 cells. These studies reveal that LOE suppresses key features of the progression of aggressive breast cancer cells and provides a basis for further definition of its underlying mechanisms of action and anticancer potential.

Antigenotoxic Effect Against Ultraviolet Radiation-induced DNA Damage of the Essential Oils from Lippia Species

The antigenotoxicity against ultraviolet radiation (UV)-induced DNA damage of essential oils (EO) from Lippia species was studied using SOS Chromotest. Based on the minimum concentration that significantly inhibits genotoxicity, the genoprotective potential of EO from highest to lowest was Lippia graveolens, thymol-RC ≈ Lippia origanoides, carvacrol-RC ≈ L. origanoides, thymol-RC > Lippia alba, citral-RC ≈ Lippia citriodora, citral-RC ≈ Lippia micromera, thymol-RC > L. alba, myrcenone-RC. EO from L. alba, carvone/limonene-RC, L. origanoides, α-phellandrene-RC and L. dulcis, trans-β-caryophyllene-RC did not reduce the UV genotoxicity at any of the doses tested. A gas chromatography with flame ionization detection analysis (GC-FID) was conducted to evaluate the solubility of the major EO constituents under our experimental conditions. GC-FID analysis showed that, at least partially, major EO constituents were water-soluble and therefore, they were related with the antigenotoxicity detected for EO. Constituents such as p-cymene, geraniol, carvacrol, thymol, citral and 1,8-cineole showed antigenotoxicity. The antioxidant activity of EO constituents was also determined using the oxygen radical antioxidant capacity (ORAC) assay. The results showed that the antigenotoxicity of the EO constituents was unconnected with their antioxidant activity. The antigenotoxicity to different constituent binary mixtures suggests that synergistic effects can occur in some of the studied EO.

Antimicrobial and seasonal evaluation of the carvacrol-chemotype oil from Lippia origanoides kunth

This study evaluated the influence of seasonal variation on the yield and composition of essential oil of Lippia origanoides occurring in the Middle Rio Amazonas, Brazil, and the impact on its antimicrobial potential. The average oil yield was 1.7% ± 0.2% in the rainy season and 1.6% ± 0.3% in the dry season. Some correlations with climatic parameters were observed. The major components were carvacrol (rainy, 43.5% ± 1.9%; dry, 41.4% ± 2.04%), thymol (rainy, 10.7% ± 1.1%; dry, 10.6% ± 0.9%), p-cymene (rainy, 9.8% ± 0.7%; dry, 10.0% ± 1.4%) and p-methoxythymol (rainy, 9.6% ± 0.8%; dry, 10.4% ± 1.4%). It was found that the antibacterial activity of L. origanoides against Staphylococcus aureus and Escherichia coli was little influenced by the changes in oil composition due to seasonal variation. Against S. aureus, the oil Minimum Inhibitory Concentration (MIC) value was 1.25 μL/mL over ten months. Against E. coli, the oil MIC values ranged from 0.15 μL/mL to 0.31 μL/mL in different months of the year. The Minimum Bactericidal Concentration (MBC) value was 2.5 μL/mL against S. aureus and 1.25 μL/mL against E. coli. The results suggest that the antimicrobial activity identified in the oil remain unchanged for the full year, allowing its medicinal use without any risk of loss or absence of the active principles of the plant.

Composition, anti-quorum sensing and antimicrobial activity of essential oils from Lippia alba

Many Gram-negative pathogens have the ability to produce N-acylhomoserine lactones (AHLs) as signal molecules for quorum sensing (QS). This cell-cell communication system allows them to coordinate gene expression and regulate virulence. Strategies to inhibit QS are promising for the control of infectious diseases or antibiotic resistant bacterial pathogens. The aim of the present study was to evaluate the anti-quorum sensing (anti-QS) and antibacterial potential of five essential oils isolated from Lippia alba on the Tn-5 mutant of Chromobacterium violaceum CV026, and on the growth of the gram-positive bacteria S. aureus ATCC 25923. The anti-QS activity was detected through the inhibition of the QS-controlled violacein pigment production by the sensor bacteria. Results showed that two essential oils from L. alba, one containing the greatest geranial:neral and the other the highest limonene:carvone concentrations, were the most effective QS inhibitors. Both oils also had small effects on cell growth. Moreover, the geranial/neral chemotype oil also produced the maximum zone of growth inhibition against S. aureus ATCC 25923. These data suggest essential oils from L. alba have promising properties as QS modulators, and present antibacterial activity on S. aureus.

Essential oils with insecticidal activity against larvae of Aedes aegypti (Diptera: Culicidae)

Insecticidal activity of the essential oils (EOs) isolated from Tagetes lucida, Lippia alba, Lippia origanoides, Eucalyptus citriodora, Cymbopogon citratus, Cymbopogon flexuosus, Citrus sinensis, Swinglea glutinosa, and Cananga odorata aromatic plants, grown in Colombia (Bucaramanga, Santander), and of a mixture of L. alba and L. origanoides EOs were evaluated on Aedes (Stegomyia) aegypti Rockefeller larvae. The EOs were extracted by microwave-assisted hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS). The main components of the EOs were identified using their linear retention indices and mass spectra. The lethal concentrations (LCs) of the EOs were determined between the third and fourth instar of A. aegypti. LC50 was determined by probit analysis using mortality rates of bioassays. All essential oils tested showed insecticidal activity. The following values were obtained for C. flexuosus (LC50 = 17.1 ppm); C. sinensis (LC50 = 20.6 ppm); the mixture of L. alba and L. origanoides (LC50 = 40.1 ppm); L. alba (LC50 = 42.2 ppm); C. odorata (LC50 = 52.9 ppm); L. origanoides (LC50 = 53.3 ppm); S. glutinosa (LC50 = 65.7 ppm); T. lucida (LC50 = 66.2 ppm); E. citriodora (LC50 = 71.2 ppm); and C. citratus (LC50 = 123.3 ppm). The EO from C. flexuosus, with citral (geranial + neral) as main component, showed the highest larvicidal activity.

Chromatographic and mass spectrometric characterization of essential oils and extracts from Lippia (Verbenaceae) aromatic plants

Analytical methodologies based on GC and HPLC were developed for the separation and quantification of carnosic acid, ursolic acid, caffeic acid, p-coumaric acid, rosmarinic acid, apigenin, luteolin, quercetin, kaempferol, naringenin, and pinocembrin. These methods were used to characterize essential oils and extracts obtained by solvent (methanol) and by supercritical fluid (CO(2)) extraction from stems and leaves of Lippia (Verbenaceae family) aromatic plants (Lippia alba, Lippia origanoides, Lippia micromera, Lippia americana, Lippia graveolens, and Lippia citriodora). Supercritical CO(2) extraction isolated solely pinocembrin and narigenin from three L. origanoides chemotypes. Solvent extracts possessed a more varied composition that additionally included apigenin, quercetin, and luteolin. Solvent extraction afforded higher overall flavonoid yields from all species in comparison with supercritical CO(2) extraction. Pinocembrin was determined in L. origanoides extract at a concentration of 30 mg/g of plant material, which is more than ten times higher than the amount at which polyphenols are regularly found in aromatic plant extracts.

The influence of organic solvents on estimates of genotoxicity and antigenotoxicity in the SOS chromotest

In this work, the toxicity and genotoxicity of organic solvents (acetone, carbon tetrachloride, dichloromethane, dimethylsulfoxide, ethanol, ether and methanol) were studied using the SOS chromotest. The influence of these solvents on the direct genotoxicity induced by the mutagens mitomycin C (MMC) and 4-nitroquinoline-1-oxide (4-NQO) were also investigated. None of the solvents were genotoxic in Escherichia coli PQ37. However, based on the inhibition of protein synthesis assessed by constitutive alkaline phosphatase activity, some solvents (carbon tetrachloride, dimethylsulfoxide, ethanol and ether) were toxic and incompatible with the SOS chromotest. Solvents that were neither toxic nor genotoxic to E. coli (acetone, dichloromethane and methanol) significantly reduced the genotoxicity of MMC and 4-NQO. When these solvents were used to dissolve vitamin E they increased the antigenotoxic activity of this compound, possibly through additive or synergistic effects. The relevance of these results is discussed in relation to antigenotoxic studies. These data indicate the need for careful selection of an appropriate diluent for the SOS chromotest since some solvents can modulate genotoxicity and antigenotoxicity.

Composition of three essential oils, and their mammalian cell toxicity and antimycobacterial activity against drug resistant-tuberculosis and nontuberculous mycobacteria strains

Tuberculosis (TB) is the most ancient epidemic disease in the world and a serious opportunistic disease in HIV/AIDS patients. The increase in multidrug resistant Mycobacterium tuberculosis (MDR-TB, XDR-TB) demands the search for novel antimycobacterial drugs. Essential oils (EOs) have been widely used in medicine and some EOs and their major components have been shown to be active against M. tuberculosis. The aim of this work was to evaluate the antimycobacterial and cell toxicity activities of three EOs derived from Salvia aratocensis, Turnera diffusa and Lippia americana, aromatics plants collected in Colombia. The EOs were isolated by hydrodistillation and analyzed by GC/MS techniques. The EOs were tested against 15 Mycobacterium spp using a colorimetric macrodilution method and against mammalian Vero and THP-1 cells by MTT. The activity was expressed as minimal concentration in microg/mL that inhibits growth, and the concentration that is cytotoxic for 50 or 90% of the cells (CC50 and CC90). The major components were epi-alpha-cadinol (20.1%) and 1,10-di-epi-cubenol (14.2%) for Salvia aratocensis; drima-7,9(11)-diene (22.9%) and viridiflorene (6.6%) for Turnera diffusa; and germacrene D (15.4%) and trans-beta- caryophyllene (11.3%) for Lippia americana. The most active EO was obtained from S. aratocensis, with MIC values below 125 microg mL(-1) for M. tuberculosis Beijing genotype strains, and 200 to 500 microg mL(-1) for nontuberculous mycobacterial strains. The EOs were either partially or non toxic to Vero and THP-1 mammalian cells with CC50 values from 30 to > 100 microg mL(-1), and a CC90 > 100 microg mL(-1). The EOs obtained from the three aromatic Colombian plants are an important source of potential compounds against TB. Future studies using the major EO components are recommended.