Aloysia Polystachya Research Articles

Cardioprotective Effects of Aloysia polystachya Essential Oil on a Rat Model with Multiple Cardiovascular Risk Factors.

Traditional medicine is a frequently utilized method to treat cardiovascular disease and its primary risk factors, including hypertension and dyslipidemia. Aloysia polystachya is a species that is commonly employed to treat various pathological conditions, and it has already been identified as having some cardioprotective effects. This study aimed to investigate the protective effects of the essential oil extracted from the leaves of A.polystachya in a rat model that simulates multiple cardiovascular risk factors. We evaluate the acute toxicity, as well as the cardioprotective effects, by giving different doses of A.polystachya essential oil (1.47 mg/kg, 4.40 mg/kg, and 13.20 mg/kg) over a period of 42 days. The control group was treated with rosuvastatin (5 mg/kg). At the end of the treatments, the renal function, electrocardiography, blood pressure, vascular reactivity, serum biochemical profile, and organ histopathology were evaluated. The main compounds identified in the essential oil of A.polystachya using gas chromatography coupled with mass spectrometry were beta-myrcene (1.08%), limonene (40.13%), and carvone (56.47%). The essential oil of A.polystachya not only lacks acute toxicity but also mitigates the reduction in the excretion of sodium, chloride, and creatinine in urine. Furthermore, it reduces electrocardiographic abnormalities and decreases blood pressure levels. Moreover, this treatment prevents an elevation in markers of inflammation and oxidative stress in the bloodstream. Our findings indicate significant cardioprotective effects of the essential oil of A.polystachya against multiple risk factors for cardiovascular diseases in hypertensive rats.

Evidence of the Cardioprotective Effects of Aloysia polystachya in Isoproterenol-Induced Myocardial Infarction in Rats

Aloysia polystachya is a plant species that is widely used in Brazilian folk medicine for the treatment of different disorders that affect the cardiovascular system. The aim of the study was to investigate the cardioprotective effects of an ethanol-soluble fraction of A. polystachya (ESAP) on isoproterenol-induced myocardial infarction in rats. Different groups of rats (n = 8) were orally treated with ESAP (30, 100, and 300 mg/kg), carvedilol (10 mg/kg), or vehicle (filtered water; 1 mL/100 g) for 7 days. Naive rats received no treatment. On the morning of day 6, acute myocardial infarction was induced by the acute oral administration of isoproterenol (100 mg/kg). On the morning of day 8, all rats underwent electrocardiography and transthoracic echocardiography. Blood samples were then collected, and serum levels of creatine kinase-MB fraction (CK-MB) and cardiac troponin T (cTNT) were quantified. ESAP significantly reduced electrocardiographic changes, improved the ventricular ejection fraction, and reduced serum levels of CK-MB and cTNT in infarcted rats. The cardioprotective effects of ESAP could be exploited as an effective tool against isoproterenol-induced myocardial infarction in rats.

Prescription patterns of herbal medicines at a Brazilian Living Pharmacy: The Farmácia da Natureza experience, 2013–2019

IntroductionHerbal medicines are an important part of healthcare worldwide. In Brazil, the national authorities issued the concept of “living pharmacies”, that produce and offer herbal medicines in the Brazilian unified public health system. Farmácia da Natureza (Nature’s Pharmacy) is a living pharmacy and a single, not-for-profit institution that integrates traditional and scientific knowledge on medicinal plants, along with the preservation of Brazilian biodiversity, with benefits to the health of the population that uses herbal drugs. A six-year experience of medical prescription of herbal medicines at Farmácia da Natureza is reported MethodsA retrospective, descriptive analysis of data on medical prescriptions of herbal medicines was conducted (September 2013 to December 2019) retrieved from a computerized database. ResultsA total of 47,418 prescription items for 4739 patients were analyzed. The most frequent pharmaceutical forms were tinctures (39.6%); capsules containing powdered plant material (20.7%); creams, ointments, or gels (12.3%); and aqueous extracts (11.7%). The five most frequently prescribed single-constituent herbal medicines were: Curcuma longa L. (Zingiberaceae); Valeriana officinalis L. (Caprifoliaceae); Aloysia polystachya (Griseb.) Moldenke (Verbenaceae); Eclipta prostrata (L.) L. (Asteraceae); and Baccharis trimera (Less.) DC. (Asteraceae). Nearly half of the plants were naturally occurring in Brazil, while more than 80% of the products were not present in Brazilian official documents. ConclusionAt Farmácia da Natureza, herbal medicines are usually prescribed as tinctures and capsules containing powdered plant material, but other pharmaceutical forms are also prescribed. Half of the plants are of Brazilian origin and almost all preparations are galenic formulations.

Dynamized Aloysia Polystachya (Griseb.) Essential Oil: A Promising Antimicrobial Product.

Compounds from vegetal matter have therapeutic potential to control highly prevalent microorganisms that are resistant to commonly used antimicrobial drugs. Dynamization of compounds can either maintain or improve their therapeutic effects, and make their use safer, especially those compounds whose therapeutic dose is close to the toxic limit. Aloysia polystachya (Griseb.) stands out among aromatic plants with antimicrobial potential. The aim of this study was to evaluate the antimicrobial activity of dynamized and crude forms of A. polystachya essential oil against Candida albicans, Escherichia coli and Staphylococcus aureus. Essential oil was extracted from A. polystachya dry leaves, solubilized, and dynamized at 1 cH potency as recommended by the Brazilian Homeopathic Pharmacopoeia. Antimicrobial activity against C. albicans, E. coli and S. aureus of the samples was assayed using the plate microdilution method. Dynamized A. polystachya essential oil at the concentration of 1 μg/mL inhibited the growth of all the microbial species analyzed. The minimum inhibitory concentration of dynamized essential oil was smaller than crude essential oil for S. aureus, E. coli and C. albicans. It is reported for the first time that A. polystachya dynamized essential oil can effectively suppress microbial growth, and it is a promising adjuvant to treat infections with pathogenic S. aureus, E. coli and C. albicans.

Evaluation of the in vitro fungicidal activity of the dynamized essential oil of Aloysia polystachya before and after freezing

Background: The method of preserving substances of natural origin should not only maintain the microbiological safety of the product but also the integrity of its therapeutic potential. Essential oils obtained from plants are complex mixtures of substances and it is suggested to keep them under refrigeration for better conservation. On the other hand, homeopathic mother tincture prepared from plant is kept at room temperature. Aim: This work aimed to evaluate if the freezing process changes the in vitro antifungal activity potential of the homeopathic preparation Aloysia polystachya 1CH against Candida albicans. Methodology: The inoculum of C. albicans ATCC 10231 was cultivated in culture médium Sabouroud (Himedia®), standardized on a spectrometer and distributed in a 96-well plate. Then, A. polystachya 1CH was added to the wells, prepared according to the Brazilian Homeopathic Pharmacopoeia (FHB, 3rd edition) from A. polystachya essencial oil. An aliquot of this homeopathic preparation was frozen and after 40 days it was submitted to the same methodology for evaluation of the antifungal activity. After incubation, the plates were read with triphenyltetrazolic (TTC) (Vetec®). Results and discussion: The results of the in vitro evaluation showed that the freezing process retained the antifungal activity of the dynamized essential oil of A. polystachya 1CH against C. albicans. Conclusion: Under the conditions evaluated in this study, the freezing method presented as a viable method of conservation of dynamized plant material.

Antioxidant and Anti-Proliferative Activity of Essential Oil and Main Components from Leaves of Aloysia polystachya Harvested in Central Chile.

The aim of this study was to determine, first, the chemical composition of Aloysia polystachya (Griseb) Moldenke essential oil, from leaves harvested in central Chile; and second, its antioxidant and cytotoxic activity. Eight compounds were identified via gas chromatography–mass spectrometry (GC–MS) analyses, with the most representative being R-carvone (91.03%), R-limonene (4.10%), and dihydrocarvone (1.07%). For Aloysia polystachya essential oil, antioxidant assays (2,2-diphenyl-1-picrylhydrazyl (DPPH), H2O2, ferric reducing antioxidant power (FRAP), and total reactive antioxidant potential (TRAP)) showed good antioxidant activity compared to commercial antioxidant controls; and anti-proliferative assays against three human cancer cell lines (colon, HT-29; prostate, PC-3; and breast, MCF-7) determined an IC50 of 5.85, 6.74, and 9.53 µg/mL, and selectivity indices of 4.75, 4.12, and 2.92 for HT-29, PC-3, and MCF-7, respectively. We also report on assays with CCD 841 CoN (colon epithelial). Overall, results from this study may represent, in the near future, developments for natural-based cancer treatments.

Abstract 494: Effect of Aloysia polystachya in cancer stem cells of colorectal cancer

Abstract Colorectal cancer (CRC) is one of the most commonly diagnosed cancers and the Cancer Stem Cells (CSC) are the responsible of CRC persistence. Aloysia polystachya (AP) is an aromatic native plant of Verbenaceae family which is widely distributed and consumed in infusions in subtropical regions of South America. Its effects include diuretic, sedative, antispasmodic activities. We have previously demonstrated that AP extract has a cytotoxic effect in several human tumor cell lines, including apoptosis. The aim of this work was to investigate the cytotoxic effects of AP in vitro and in vivo in a CRC model. Therefore, CRC cell lines CT26 (murine) and HCT116 (human), were stimulated with AP extract or vehicle, with or without 5-fluorouracyle (5-FURA) and the survival and CSC properties were determined. The survival was measured after crystal violet staining at 570nm and CSC phenotype was determined by measuring the plurytpotency markers (CD133, OCT4 and Nanog by PCR and IFI), colony formation by clonogenic assay and HOESCHT efflux capacity (chemotherapeutic drugs efflux via ABCG2-transporters). In vivo experiments involved male BALB/c mice that were subcutaneously inoculated with murine CRC CT26 cell line. Once the tumor was detected, animals were treated twice a week (days 14, 17, 21, 24 and 28) with an intraperitoneal injection with AP and the sub-effective dose of 5-FURA (5mg/kg). Normal animals, not inoculated with CT26 cells were also used as control for histological analysis.The tumor size was determined twice a week. After 30 days, the mice were sacrificed and necropsied and the histopathology of tumors and the liver sections was performed by staining with hematoxylin and eosin. We found that AP extract decreased significantly the expression level of pluripotency markers, the colony formation and the efflux capacity of chemotherapeutic drugs respect to control cells and increased the cell death induced by 5-FURA treatment respect to cells stimulated with 5-FURA alone (P<0.05; Tukey test). We found that tumor growth was significantly inhibited by AP or AP plus 5-FURA respect to control animals without treatment or treated with 5-FURA alone (p<0.05; Tukey test). Histopathological analysis of tumor sections shown some necrosis area only in animals treated with AP or AP plus 5-FURA while the hepatic parenchyma shown a preserved architecture, confirming non-toxic effects of AP in vivo. Our results demonstrate that AP is capable to induce the cell death of CRC, resulted effective in vivo, non-toxic and has the ability to reduce the CSC side population. Being CSC the most resistant to chemotherapeutic drugs, responsible of cancer progression and perpetuation, the autochthonous plant derivatives could be attractive tools to be investigated as future oncologic therapeutics. Citation Format: Mileni Soares-Machado, Alejandra Palma, Laura Panelo, Leonardo Paz, Francisco Rosa, Cecilia Lira, Pablo Azurmendi, Fernanda Rubio, Guido Lenz, Alejandro Urtreger, Monica Costas. Effect of Aloysia polystachya in cancer stem cells of colorectal cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 494.

Extract from Aloysia polystachya Induces the Cell Death of Colorectal Cancer Stem Cells

Cancer stem cells (CSCs) are an important player in the resistance of cancers to therapy. In this work, we determined the flavonoids composition and biological action of Aloysia polystachya (AP) extracts in colorectal cancer. The chemical characterization of extracts was performed by HPLC. Assays of cytotoxicity, apoptosis, migration and invasion, metalloproteases activity, clonogenic growth, tumorspheres formation, Hoechts efflux, pluripotency marker expression and sensitization to chemotherapeutic drugs were performed in vitro in human HCT116 and murine CT26 colorectal cancer cells. The AP toxicity and effect in tumor growth administered alone or in combination with 5- Fluorouracile was analyzed in vivo, including histopathological studies. We found that AP extracts induced in vitro the apoptosis of colorectal cancer cell lines decreasing the CSC proportion. Moreover, they were capable to kill 5-Fluorouracile resistant side population cells. At not toxic doses in vivo, AP extracts inhibited tumor growth. Regarding the ability to reduce the CSC population, AP extracts deserves to be investigated as a useful therapy for colorectal cancer treatment.

Anxiolytic and Antidepressant Effects of the Hydroethanolic Extract from the Leaves of Aloysia polystachya (Griseb.) Moldenke: A Study on Zebrafish (Danio rerio).

Medicinal plants such as Aloysia polystachya are often used in the treatment of psychiatric diseases, including anxiety- and depression-related humor disturbances. In folk medicine, A. polystachya is used to treat digestive and respiratory tract disturbances, as a sedative and antidepressant agent, and as a tonic for the nerves. This study aimed to evaluate the antidepressant and anxiolytic effect from the hydroethanolic extract from the leaves of Aloysia polystachya (HELAp) in zebrafish. The extract was analyzed through ultra-performance liquid chromatography-mass spectroscopy (UPLC-MS) and the main compound detected was acteoside. HELAp was administered orally (10 mg/kg) and through immersion (mg/L). The anxiolytic activity was evaluated through the scototaxis (light–dark) test using caffeine as an anxiogenic agent and buspirone as a positive control. The parameters assessed were: period spent in the white compartment (s), latency (s), alternations (n), erratic swims (n), period of freezing (s), thigmotaxis (s), and risk evaluation (n). The antidepressant effect was evaluated through the novel tank diving test using 1% ethanol, unpredictable chronic stress, and social isolation as depressors; fluoxetine was used as a positive control. The parameters assessed were: period spent at the top of the tank, latency, quadrants crossed, erratic swim, period of freezing, and distance of swam. The main chemical compound of HELAp was acteoside. The administration of the extract on zebrafish managed to revert the anxiogenic effect of caffeine without impairing their locomotion. Additionally, the treatment exerted antidepressant activity similarly to fluoxetine. Overall, the results suggest a significant anxiolytic and antidepressant activity to the extract, which is probably due to the presence of the major compound, acteoside.

Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) powdered leaves are effective in treating anxiety symptoms: A phase-2, randomized, placebo-controlled clinical trial

Ethnopharmacological relevanceAloysia polystachya (Griseb.) Moldenke (Verbenaceae) is a plant traditionally used as medicine for anxiety symptoms. This activity was confirmed in preclinical studies. However, its efficacy was never studied in human clinical trials. Aim of the studyWe aimed to test the hypothesis that the herbal medicine of A. polystachya is superior to placebo for the treatment of anxiety-related symptoms in adults after 8 weeks. Patients and methodsThis was a randomized, double-blind, placebo-controlled, phase-2 clinical trial. Fifty-four adults with self-reported anxiety symptoms were randomly allocated to receive either capsules containing A. polystachya powdered leaves (300 mg, twice a day) or placebo (maltodextrin), for 8 weeks. The intensity of anxiety symptoms was assessed by the Hamilton Anxiety Ranking Scale (HAM-A) at baseline and after 2, 4 and 8 weeks. All analyses were adjusted for physical activity (assessed by the International Physical Activity Questionnaire [IPAQ], short version) and gender. ResultsWe confirmed the presence of acteoside (chromatographic analysis) and carvone and limonene (gas chromatography) as major constituents in our plant material. Only patients that received A. polystachya experienced a significant decrease in their HAM-A scores, with none or mild side-effects. ConclusionAdministration of powdered leaves of A. polystachya, rich in acteoside, carvone and limonene, to adults with anxiety symptoms was significantly superior to placebo in decreasing HAM-A scores after 8 weeks. This finding confirms the ethnopharmacological use of this plant for anxiety symptoms.

Identification and determination of bioactive phenylpropanoid glycosides of Aloysia polystachya (Griseb. et Moldenke) by HPLC-MS

Aloysia polystachya (Griseb. et Moldenke) has not been deeply investigated in past years and currently data about its chemical composition are limited. Phenolic compounds characterization can be very difficult in vegetable matrices, owing to bonds to sugar moieties or conjugation, giving rise to complex structures. In this work, methanolic extracts of Aloysia polystachya leaves were analyzed by HPLC-ESI-MS, the favourite technique for the separation and quantification of their polyphenols. To assess the complete characterization and quantification of the phenylpropanoid fraction, three different MS techniques have been coupled to HPLC: ion trap mass spectrometry (Ion Trap LC/MS), quadrupole-time of flight high resolution mass spectrometry (Q-TOF HRMS) and triple-quadrupole (TQ LC/MS) for the quantification. Eleven phenylpropanoid glycosides were identified and quantified and, among them, the compounds forsythoside A, plantainoside C, purpureaside D, martynoside and its two isomers were detected for the first time to the best of our knowledge. The results presented here could be helpful to assess the quality of this plant and could further contribute to the chemotaxonomy of the genus.

The potential application of plant essential oils to control Pediculus humanus capitis (Anoplura: Pediculidae).

The human head louse, Pediculus humanus capitis (Anoplura: Pediculidae), is an ectoparasite confined to the scalp and human hairs. The repeated use of insecticides for the control of head lice during past decades has resulted in the development of marked levels of resistance. Natural compounds such as essential oils (EOs) have been suggested as alternative sources for insect control agents. In order to introduce a new pediculicide based on EOs, the effectiveness of the product and their effects on human being must be analyzed. In consequence, the biological activity of EOs from the leaves and fruits of Schinus areira (Anacardiaceae) and the leaves of Thymus vulgaris (Lamiaceae), Aloysia polystachya and Aloysia citriodora (Verbenacea) were evaluated against the eggs and adults of P. humanus capitis by fumigant and contact toxicity bioassays. Additionally, dermal corrosion/irritation tests were performed on New Zealand albino rabbits. In a fumigant bioassay, EOs from the leaves and fruits of S. areira were the most toxic against P. humanus capitis adults while these EOs and T. vulgaris were the most effective against the eggs. In contact bioassay, the EO from T. vulgaris was the most toxic against both stages. In the corrosion/irritation tests, the EOs did not produce dermal effects. According to the results, the essential oils from the leaves of T. vulgaris would be a valid tool for the management of P. humanus capitis. This EO produces a high knockdown effect in adults (followed by mortality) and toxicity in the eggs when it is applied for 21 min at a low concentration.

Composition, Repellent, and Insecticidal Activities of Two South American Plants against the Stored Grain Pests Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae)

As part of a screening program to evaluate the biological activity of indigenous plants, we report the composition and the bioactivity of essential oils (EOs) extracted from Té de Burro Aloysia polystachya [(Griseb.) Moldenke] and Lemon Verbena Aloysia citriodora [Palau] against two of the most widespread secondary pests of stored products, the red flour beetle Tribolium castaneum [Herbst] and the confused flour beetle Tribolium confusum [Jacqueline du Val]. Analysis by gas chromatography-mass spectrometry of the EOs led the identification of their major constituents and their relative proportions. EO of A. citriodora showed the highest repellent activity against both beetles (>70%). On the other hand, both plants showed fumigant toxicity only against T. confusum, without significant differences between them (LC50 values of 5.92 and 5.53 mg/L air for A. polystachya and A. citriodora, resp.). For contact toxicity (topical applications) the EO of A. polystachya was more effective (LD50 = 7.35 μg/insect) than the EO of A. citriodora (LD50 = 13.8 μg/insect) only against T. castaneum. On the other hand, T. confusum was not susceptible by contact to any of these EOs. These results provide important tools for the development of an Integrated Pest Management (IPM) program.

Plant-Based Medicines for Anxiety Disorders, Part 1

Research in the area of herbal psychopharmacology has revealed a variety of promising medicines that may provide benefit in the treatment of general anxiety and specific anxiety disorders. However, a comprehensive review of plant-based anxiolytics has been absent to date. This article (part 1) reviews herbal medicines for which only preclinical investigations for anxiolytic activity have been performed. In part 2, we review herbal medicines for which there have been clinical investigations for anxiolytic activity. An open-ended, language-restricted (English) search of MEDLINE (PubMed), CINAHL, Scopus and the Cochrane Library databases was conducted (up to 28 October 2012) using specific search criteria to identify herbal medicines that have been investigated for anxiolytic activity. This search of the literature revealed 1,525 papers, from which 53 herbal medicines were included in the full review (having at least one study using the whole plant extract). Of these plants, 21 had human clinical trial evidence (reviewed in part 2), with another 32 having solely preclinical studies (reviewed here in part 1). Preclinical evidence of anxiolytic activity (without human clinical trials) was found for Albizia julibrissin, Sonchus oleraceus, Uncaria rhynchophylla, Stachys lavandulifolia, Cecropia glazioui, Magnolia spp., Eschscholzia californica, Erythrina spp., Annona spp., Rubus brasiliensis, Apocynum venetum, Nauclea latifolia, Equisetum arvense, Tilia spp., Securidaca longepedunculata, Achillea millefolium, Leea indica, Juncus effusus, Coriandrum sativum, Eurycoma longifolia, Turnera diffusa, Euphorbia hirta, Justicia spp., Crocus sativus, Aloysia polystachya, Albies pindrow, Casimiroa edulis, Davilla rugosa, Gastrodia elata, Sphaerathus indicus, Zizyphus jujuba and Panax ginseng. Common mechanisms of action for the majority of botanicals reviewed primarily involve GABA, either via direct receptor binding or ionic channel or cell membrane modulation; GABA transaminase or glutamic acid decarboxylase inhibition; a range of monoaminergic effects; and potential cannabinoid receptor modulation. Future research should focus on conducting human clinical trials on the plants reviewed with promising anxiolytic activity.

English

Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) is considered as a medicinal plant by Argentineans and Brazilians, being popularly used as sedative, eupeptic and carminative agent. The high amount of carvone produced by this species could justify its use in the treatment of some digestive disorders. The aim of this work was to evaluate the effect of the time of leaf harvesting on the composition of A. polystachya essential oil. The antimicrobial activity of this essential oil was evaluated against Escherichia coli, Staphylococcus aureus, three Candida strains and Trichophyton rubrum. Essential oils from dry and fresh leaves obtained by hydrodistillation were analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). The chemical profile of A. polystachya essential oils varied according to day-time harvesting of the plant material though they were basically composed of carvone and limonene. The antifungal activity of the essential oils against clinical isolates of Tricophyton rubrum, Candida albicans, C. krusei and C. famata was validated.   Key words: Verbenaceae, antimicrobial activity, limonene, carvone.

Repellence of essential oils of aromatic plants growing in Argentina against Aedes aegypti (Diptera: Culicidae)

Mosquitoes are vectors of pathogens to humans and domestic animals and may also have economical impacts. One approach to prevent mosquito-borne diseases is bite deterrence through the application of repellents. Currently, there is an interest to search for alternative bioactive products to the synthetic active ingredients most widely used in insect repellents. Repellence against Aedes aegypti of essential oils extracted from Acantholippia salsoloides, Aloysia catamarcensis, Aloysia polystachya, Lippia integrifolia, Lippia junelliana (Verbenaceae), Baccharis salicifolia, Euphatorium buniifolium, and Tagetes filifolia (Asteraceae) were assessed. Tests were conducted by alternatively exposing untreated and treated forehand to the mosquitoes and counting probing attempts. All essential oils tested were significantly repellent against A. aegypti when compared to untreated controls; L. junelliana was the most repellent and T. filifolia was the least based on the response of the mosquitoes to different concentrations of the essential oils (EO). Repellence may be attributed to the respective main components of each EO.

Biological Activity of Essential Oils from Aloysia polystachya and Aloysia citriodora (Verbenaceae) against the Soybean Pest Nezara viridula (Hemiptera: Pentatomidae)

The objective of the current study was to determine the chemical constituents, ovicidal activity, fumigant, contact toxicity and repellent effects of essential oils isolated by hydrodistillation from Aloysia polystachya and A. citriodora against eggs and second instar nymphs of Nezara viridula. The major components were carvone (83.5%) for A. polystachya, and citronellal (51.3%) and sabinene (22.9%) for A. citriodora. The ovicidal activity of both oils was tested by topical application at different concentrations ranging from 1.2 to 12.5 microg/egg; all concentrations had a toxic effect. Data probit analysis showed that the LC50 value for A. polystachya was 2.3 microg/egg and for A. citriodora 1.9 microg/egg. The fumigant activity was evaluated in an enclosed chamber. The toxicity increased with concentration from 11 to 176 microg/mL air, and with exposure times from 1 to 48 h. The LC50 values for A. polystachya and A. citriodora were 29.9 and 13.5 microg/mL air 24 h after treatment, respectively. To evaluate contact activity a glass-vial bioassay was used. The toxicity increased with concentration from 2.8 to 45 microg/cm2 and with exposure time from 1 to 48 h. The LC50 for A. polystachya was 3.4 microg/cm2 and for A. citriodora 8.1 microg/cm2. The repellency bioassay demonstrated that both oils were active at the highest concentration (2.6 and 5.3 microg/mL air) and neutral at 1.3 microg/mL air. These results show that the essential oils from Aloysia polystachya and A. citriodora could be applicable to the management of populations of Nezara viridula.

Susceptibility of the Honeybee Bacterial Pathogen Paenibacillus larvae to Essential Oils Distilled from Exotic and Indigenous Argentinean Plants

Antimicrobial properties and chemical composition of eight exotic and indigenous Argentinean essential oils to control American Foulbrood (AFB) were determined. The oils tested were extracted from Artemisia absinthium, Artemisia annua, Lepechinia floribunda, Aloysia polystachya, Verbena officinalis, Wedelia glauca, Satureja odora and Hetherothalamus alienus. The components of the essential oils were identified by SPME-GC/MS analysis. The antimicrobial activity of the oils against Paenibacillus larvae were determined by broth microdilution method. Two-way ANOVA for minimum inhibitory concentrations (MICs) data and minimal bactericide concentrations (MBCs) data, indicated no significant differences between the thirteen P. larvae strains tested and highly significant differences between the oils. The antimicrobial assays showed that the oils of A. absinthium, A. annua and L. foribunda inhibited the bacterial strains at the lowest concentrations tested, MICs and MBCs averages of 393.6 mg/L to 416.7 mg/L and 517.9 mg/L to 624.4 mg/L respectively, indicating the highest inhibitory capacities. Their antimicrobial activities were attributed to the kind and the variation in percentage of the components. α-Thujone (62.3%) was largely predominant in the oil of the A. absinthium meanwhile artemisia ketone (36.3%) and 1,8-cineole (31.5%) constituted the bulk of the oil of A. annua. 1,8-Cineole (27.5%) was also very important in the composition of the oil of L. floribunda, which also possessed camphene (16.6%) and camphor (12.9%).

The antidepressant-like effects of Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) in mice

The aim of the present work is to evaluate the putative antidepressant-like effects of a hydro-ethanolic extract (CEAp) and their fractions from the aerial parts of Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) on the performance of male mice in the forced swimming test (FST). A single dose (100.0mg/kgp.o.) of CEAp, in male mice provoked a significant reduction of the immobility time (p<0.01). Such effect was also observed with short-term treatment (7 days) with single doses of 1.0 (p<0.01), 10.0 (p<0.05) and 100.0 (p<0.05)mg/kg/day of CEAp. Additionally, in a different set of experiments, repeated administration in a 24-h period (24, 18 and 1h before swimming test) with doses of 1.0 (p<0.05) and 10.0 (p<0.05)mg/kg p.o., of CEAp and 10.0mg/kgp.o., (p<0.05) of ethyl acetate fraction, provoked significant reduction of the immobility time of male mice in the FST. Moreover, it was noted important differences in the onset of the antidepressant-like effect in the FST, depending on the modality of treatment with CEAp (acute, short-term or repeated). Both, efficacy and potency were higher when repeated administration of CEAp was used, and surprisingly the dose of 10mg/kg (24, 18 and 1h before swimming test) was more effective than imipramine. In the same way, the short term administration (7 days) improved significantly efficacy and potency of the CEAp in comparison to a single dose treatment. The ethyl acetate fraction submitted to TLC demonstrated that main and minor components are phenolics and terpenes, respectively. In addition, this fraction gives a negative Shinoda's test for flavonoids. These results indicate an antidepressant-like profile of action for the hydro-ethanolic extract and the component(s) of the ethyl acetate fraction obtained from A. polystachya, which deserve further investigation.

The anxiolytic-like effects of Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) in mice

The aim of the present work is to demonstrate the putative sedative and anxiolytic-like effects of a hydro-ethanolic extract obtained from the aerial parts of Aloysia polystachya (Verbenaceae) in male mice using several behavioural assays. Groups of male mice orally treated with doses of 1.0, 10.0 and 100.0 mg/kg of the extract did not show any significant alteration of their locomotor activity, body temperature or motor coordination. The same treatment increased the duration of the sleeping time induced by 30.0 mg/kg i.p. of sodium pentobarbital. However, the sleeping time induced by ethyl ether was not modified by the oral administration of the extract, not confirming the putative sedative effect of the plant. The ethanolic extract also significantly increased the percentage of both entries (1.0 and 100.0 mg/kg) and the time spent (10.0 and 100.0 mg/kg) into the open arms of the elevated plus maze (EPM). Nevertheless, the binding of 3H-flunitrazepam ( 3H-FNZ) to the benzodiazepine binding site (BDZ-bs), in washed crude synaptosomal membranes from rat cerebral cortex, was not affected by the semi-purified components from Aloysia polystachya. These results indicate an anxiolytic-like profile of action for the extract of Aloysia polystachya without sedative side effect, being this activity probably mediated by other mechanism than BDZ-bs modulation at the GABA A receptors.