Synergism in Two-Component Insecticides with Dillapiole against Fall Armyworm.

The fall armyworm (Spodoptera frugiperda), a polyphagous insect pest, is a major threat to food production, rapidly spreading through all the tropical areas in the world. Resistance has developed to the control protocols used so far (pyrethroids, organophosphorus, and genetically modified plants), and alternative strategies must be found. The bioactivity in essential oils is usually associated with the major constituents, but synergistic interactions among the constituents (even minor ones) can improve the levels of activity considerably. Herein, we tested the insecticidal activity of several constituents of the essential oil from Piper aduncum, an Amazonian Piperaceae, both separately and as binary mixtures, through their application on the dorsal side of the larva pronotum. Dillapiole proved to be, isolated, the most active compound in this oil (LD50 = 0.35 ppm). In binary mixtures, a strong synergistic effect was observed for the pairs of dillapiole with ß-caryophyllene (LD50 = 0.03 ppm), methyl eugenol (LD50 = 0.05 ppm), and α-humulene (LD50 = 0.05 ppm). In some cases, however, antagonism was recorded, as for dillapiole + ß-pinene (LD50 = 0.44 ppm). The use of binary mixtures of essential oil constituents as low-environmental-toxicity insecticides allows a fine tuning of the insecticidal activity, and the exploitation of synergy effects.

Use and abuse of retention indices in gas chromatography.

The value of the concept of retention indices (RI) to the practice of gas chromatography (GC) is highlighted, where the RI of a compound is one component of the strategy to identify the compound. The widespread reliance on GC and then on mass spectrometry for 'identification', may result in inadequate confirmation of molecular identity. However, RI do provide a useful tentative indication of the possible molecule(s). Thus, the RI value is a useful first measure of the molecule identity, and shown here to be valuable provided limitations are recognised. An author has a responsibility to correctly calculate the index and then use the values for (tentative) identification. Tables of reference RI values are useful in this respect, but finding an 'exact match' RI value does not confirm the identity. Hence, it is necessary to understand how the RI value may be incorrectly used in this respect. The reviewer of written research is charged with ensuring the index values are applied in a rigorous manner. Selected case studies from our own work, support the care that must be exercised when reporting RI values. In terms of advanced GC operations, mention is made of multidimensional gas chromatography and comprehensive two-dimensional gas chromatography to acquire RI values on both the first and second columns in the two-column separation experiment.

Artemisia annua L. and photoresponse: from artemisinin accumulation, volatile profile and anatomical modifications to gene expression.

KEY MESSAGE: Blue and yellow light affected metabolism and the morphology. Blue and red promote the DOXP/MEP pathway. ADS gene expression was increased in plants cultivated under blue, promoting artemisinin content. Artemisinin-based combination therapies are the most effective treatment for highly lethal malaria. Artemisinin is produced in small quantities in the glandular trichomes of Artemisia annua L. Our aim was to evaluate the effect of light quality in A. annua cultivated in vitro under different light qualities, considering anatomical and morphological changes, the volatile composition, artemisinin content and the expression of two key enzymes for artemisinin biosynthesis. Yellow light is related to the increase in the number of glandular trichomes and this seemed to positively affect the molecular diversity in A. annua. Yellow light-stimulated glandular trichome frequency without triggered area enhancement, whereas blue light stimulated both parameters. Blue light enhanced the thickness of the leaf epidermis. The B-promoting effect was due to increased cell size and not to increased cell numbers. Green and yellow light positively influenced the volatile diversity in the plantlets. Nevertheless, blue and red light seemed to promote the DOXP/MEP pathway, while red light stimulates MVA pathway. Amorpha-4,11-diene synthase gene expression was significantly increased in plants cultivated under blue light, and not red light, promoting artemisinin content. Our results showed that light quality, more specifically blue and yellow light, positively affected secondary metabolism and the morphology of plantlets. It seemed that steps prior to the last one in the artemisinin biosynthesis pathway could be strongly influenced by blue light. Our work provides an alternative method to increase the amount of artemisinin production in A. annua without the use of transgenic plants, by the employment of blue light.

Biodegradation of Organophosphorus Compounds Predicted by Enzymatic Process Using Molecular Modelling and Observed in Soil Samples Through Analytical Techniques and Microbiological Analysis: A Comparison.

Organophosphorus compounds (OP) are chemicals widely used as pesticides in different applications such as agriculture and public health (vector control), and some of the highly toxic forms have been used as chemical weapons. After application of OPs in an environment, they persist for a period, suffering a degradation process where the biotic factors are considered the most relevant forms. However, to date, the biodegradation of OP compounds is not well understood. There are a plenty of structure-based biodegradation estimation methods, but none of them consider enzymatic interaction in predicting and better comprehending the differences in the fate of OPs in the environment. It is well known that enzymatic processes are the most relevant processes in biodegradation, and that hydrolysis is the main pathway in the natural elimination of OPs in soil samples. Due to this, we carried out theoretical studies in order to investigate the interactions of these OPs with a chosen enzyme-the phosphotriesterase. This one is characteristic of some soils' microorganisms, and has been identified as a key player in many biodegradation processes, thanks to its capability for fast hydrolyzing of different OPs. In parallel, we conducted an experiment using native soil in two conditions, sterilized and not sterilized, spiked with specific amounts of two OPs with similar structure-paraoxon-ethyl (PXN) and O-(4-nitrophenyl) O-ethyl methylphosphonate (NEMP). The amount of OP present in the samples and the appearance of characteristic hydrolysis products were periodically monitored for 40 days using analytical techniques. Moreover, the number of microorganisms present was obtained with plate cell count. Our theoretical results were similar to what was achieved in experimental analysis. Parameters calculated by enzymatic hydrolysis were better for PXN than for NEMP. In soil, PXN suffered a faster hydrolysis than NEMP, and the cell count for PXN was higher than for NEMP, highlighting the higher microbiological toxicity of the latter. All these results pointed out that theoretical study can offer a better comprehension of the possible mechanisms involved in real biodegradation processes, showing potential in exploring how biodegradation of OPs relates with enzymatic interactions.

Reduction of ßN-alkanoyl-5-hydroxytryptamides and diterpenes by yeast supplementation to green coffee during wet processing.

Coffee is one of the most consumed non-alcoholic beverages in the world. It is well known that some compounds present in coffee beans have important biological activities. In this study, evidence was turned to ßN-alkanoyl-5-hydroxytryptamides (C-5HTs) and to the furokaurane diterpenes cafestol and kahweol, associated with gastric irritation and increasing of blood cholesterol, respectively. Fermentation in coffee post-harvest wet process was induced by three Saccharomyces cerevisiae yeasts (for bakery, white and sparkling wines) as starter cultures. Variations in mass, time, temperature and pH (56 experiments under fractional factorial and mixture experimental designs) were tested. Substantial reductions for C-5HTs (up to 38% reduction for C20-5HT and 26% for C22-5HT) as well as for diterpenes (54% for cafestol and 53% for kahweol) were obtained after treating green coffee beans with 0.6 g of a 1:1:1 mixture the three yeasts for 12 h at 15 °C and pH 4. Caffeine and 5-CQA content, monitored in the green coffee beans, did not change. Therefore, the use of starter cultures during coffee post-harvest wet process has influence on the amount of some important compounds related to health and improves the sensory quality of the beverage.

Gas chromatography-mass spectrometry of sapucainha oil (Carpotroche brasiliensis) triacylglycerols comprising straight chain and cyclic fatty acids.

Sapucainha oil, which may be used to treat leprosy, comprises straight chain and cyclic fatty acids (FA), and triacylglycerols (TAG). The FA and TAG content of the oil sample was analysed using gas chromatography-electron ionisation mass spectrometry (GC-EIMS). FA analysis was performed after derivatisation to fatty acid methyl esters (FAME). For free FA and TAG analysis, the oil sample was dissolved in hexane and injected into a short, high-temperature column, for GC with MS analysis. Free FA and FAME were tentatively identified based on mass spectrum information of their molecular and fragment ions, as well as library matching. Overlapping TAG peaks were deconvoluted based on mass fingerprint data. The FA composition was utilised to predict possible TAG identities. FA residues of TAG were identified based on characteristic fragment ions, such as [M-RCO2]+, [RCO+128]+, [RCO+74]+ and RCO+ where R is the aliphatic hydrocarbon chain. FAME analysis showed that the cyclic FA hydnocarpic (36.1%), chaulmoogric (26.5%) and gorlic (23.6%) acids were the major components. In addition, straight chain FA such as palmitic, palmitoleic, stearic, oleic and linoleic acids were detected. Palmitic, oleic, hydnocarpic, chaulmoogric and gorlic acids were also detected as free FA in the oil sample. Six groups of TAG peaks were eluted from GC at temperatures ≥330 °C. After deconvolution and mass spectrum analysis, each TAG peak group was revealed to comprise 2 to 5 co-eluted TAG molecules; >18 TAG were identified. These TAG consisted of a mix of both cyclic and straight chain FA, but were mostly derived from cyclic FA.

Efficacy of essential oils from plants cultivated in the Amazonian Biome against gastrointestinal nematodes in sheep.

The excessive use of anthelmintics to control nematodes has resulted in anthelminthic resistance. Essential oils (EOs) are a rich source of bioactive molecules that can be assessed for their ability to control resistant parasite populations. The aims of this study were to screen EOs from 10 plant species in vitro for anthelmintic activity against Haemonchus contortus, evaluate the cytotoxicity of those EOs in a human immortalized keratinocyte cell line (HaCaT), and test the most promising EO candidate in vivo in Santa Inês sheep. The efficacy was investigated in vitro using an egg hatch test (EHT) and a larval development test (LDT). EO cytotoxicity was evaluated with the sulforhodamine-B assay. In the in vivo experiment, 28 Santa Inês sheep naturally infected were distributed into groups: G1-Mentha arvensis (EO5), 200 mg kg-1; G2-menthol, 160 mg kg-1; G3-negative control; and G4-positive control (monepantel). EO5, from M. arvensis (86.7% menthol), had the lowest LC50 and LC90 values in the EHT (0.10, 0.27 mg mL-1, respectively), good performance in the LDT (0.015, 0.072 mg mL-1, respectively), and the lowest cytotoxicity (190.9 µg mL-1) in HaCaT cells. In the in vivo test, a single dose of the EO5 (200 mg kg-1 BW) had an efficacy of approximately 50% on days 1, 14, and 21; however, values were not significantly from day 0. Conversely, pure menthol at a dose of 160 mg kg-1 BW showed no in vivo efficacy. This can be attributed to key factors related to bioavailability and pharmacology of terpenes in the host organism, as well as to the fact that menthol is mainly excreted as glucuronides in urine. Thus, further studies should be conducted with formulation systems that deliver bioactives directly to the abomasum, focusing on terpenes, whose excretion route is mainly via faeces.

Piper Essential Oils Inhibit Rhizopus oryzae Growth, Biofilm Formation, and Rhizopuspepsin Activity.

Piper is the largest genus of the Piperaceae family. The species of this genus have diverse biological activities and are used in pharmacopeia throughout the world. They are also used in folk medicine for treatment of many diseases in several countries including Brazil, China, India, Jamaica, and Mexico. In Brazil, Piper species are distributed throughout the national territory, making this genus a good candidate for biological activity screening. During our studies with Piper essential oils, we evaluated its activity against Rhizopus oryzae, the main agent of mucormycosis. The main compounds of seven Piper essential oils analyzed were Piper callosum-safrole (53.8%), P. aduncum-dillapiole (76.0%), P. hispidinervum-safrole (91.4%), P. marginatum-propiopiperone (13.2%), P. hispidum-γ-terpinene (30.9%), P. tuberculatum-(E)-caryophyllene (30.1%), and Piper sp.-linalool (14.6%). The minimum inhibitory concentration of Piper essential oils against R. oryzae ranged from 78.12 to >1250 µg/mL. The best result of total inhibition of biofilm formation was obtained with Piper sp. starting from 4.88 µg/mL. Considering the bioactive potential of EOs against planktonic cells and biofilm formation of R. oryzae could be of great interest for development of antimicrobials for therapeutic use in treatment of fungal infection.

Ionic liquid capillary columns for analysis of multi-component volatiles by gas chromatography-mass spectrometry: performance, selectivity, activity and retention indices.

This study investigates applications and performance evaluation of SLB-IL60, SLB-IL76 and SLB-IL111 columns, in relation to a DB-Wax column, for the analysis of coffee volatile compounds. Both standards and an authentic coffee sample were analysed, with solid-phase microextraction (SPME) sampling of the latter. A cryofocusing method was applied to improve resolution of the earliest eluting peaks using splitless injection SPME sample analysis. The Grob test was used to verify the inertness and efficiency of the columns, helping to understand the interactions between analytes and stationary phases, particularly toward more polar coffee analytes. A DB-5 column was used only in analysis of n-alkanes and Grob test mixtures as an apolar reference. The evaluated ionic liquid columns showed a moderate acid-base character and low inertness for compounds with hydrogen bond capabilities, especially for the hydroxylated analytes, 2,3-butanediol in the Grob test, and furanones and acids in the coffee standards. The columns exhibiting the best resolution and efficiency were DB-Wax and SLB-IL60, both for samples and standards. Although the DB-Wax column is preferred for analysis of coffee volatiles, due to better inertness, the evaluated ionic liquid columns allowed identification of compounds that were not observed in separations with the Wax-phase column in this work. Among these compounds is 3,4-dimethyl-2,5-furandione, seldom reported in the literature of coffee. Proposed improvement by the manufacturer in the inertness of the columns evaluated in this study may lead to better results; so future versions of IL phases may be better applied in the separation of target analytes, especially those with basic character. Graphical abstract Illustrative representation of the sample (coffee) and the chemical structures of the stationary phases of the ionic liquid capillary columns used as object of study in the present work.

Development and evaluation of an inhalation chamber for in vivo tests

ABSTRACT The bioavailability, toxicity, and therapeutic efficacy of a drug is directly related to its administration route. The pulmonary route can be accessed by inhalation after fumigation, vaporization or nebulization. Thus, pharmacological and toxicological evaluation accessed by an apparatus specifically designed and validated for this type of administration is extremely important. Based on pre-existing models, an inhalation chamber was developed. This presents a central structure with five animal holders. The nebulized air passes directly and continuously through these holders and subsequently to an outlet. Evaluation of its operation was performed using clove essential oil, a nebulizer, and a flow meter. The air within the chamber was collected by static headspace and analyzed by gas chromatography with a flame ionization detector. For this purpose, a 2.5 minutes chromatographic method was developed. The air flow in each of the five outputs was 0.92 liters per minute. During the first minute, the chamber became saturated with the nebulized material. Homogeneous and continuous operation of the chamber was observed without accumulation of volatile material inside it for 25 minutes. The inhalation chamber works satisfactorily for in vivo tests with medicines designed to be administrated by inhalation.

Development and evaluation of an inhalation chamber for in vivo tests.

The bioavailability, toxicity, and therapeutic efficacy of a drug is directly related to its administration route. The pulmonary route can be accessed by inhalation after fumigation, vaporization or nebulization. Thus, pharmacological and toxicological evaluation accessed by an apparatus specifically designed and validated for this type of administration is extremely important. Based on pre-existing models, an inhalation chamber was developed. This presents a central structure with five animal holders. The nebulized air passes directly and continuously through these holders and subsequently to an outlet. Evaluation of its operation was performed using clove essential oil, a nebulizer, and a flow meter. The air within the chamber was collected by static headspace and analyzed by gas chromatography with a flame ionization detector. For this purpose, a 2.5 minutes chromatographic method was developed. The air flow in each of the five outputs was 0.92 liters per minute. During the first minute, the chamber became saturated with the nebulized material. Homogeneous and continuous operation of the chamber was observed without accumulation of volatile material inside it for 25 minutes. The inhalation chamber works satisfactorily for in vivo tests with medicines designed to be administrated by inhalation.

Oxidation of monoterpenes in Protium heptaphyllum oleoresins.

Protium heptaphyllum (Burseraceae) oleoresins are rich in volatile monoterpenes, exhibiting a chemical composition that can be strongly altered with time. The present work aimed to discuss the temporal change of the volatile composition of these oleoresins, and search for related supporting evidence. Samples of P. heptaphyllum oleoresin were collected separately for fresh (n = 10) and aged (n = 8) oleoresins, with the essential oils obtained by hydrodistillation analyzed by GC-FID and GC-MS. Fresh oleoresins were characterized by a high content of terpinolene (28.2-69.7%), whereas aged ones contained large amounts of p-cymene (18.7-43.0%) and p-cymen-8-ol (8.2-31.8%). Multivariate analyses were performed based on the yield and major essential oil components to clearly demonstrate the existence of two subsets (fresh and aged oleoresins). In addition, an analysis of the partial genome sequencing of the species was carried out, producing the largest amount of data for the genus Protium. Subsequently, were searched for nucleotide sequences responsible for the enzymes involved in the biosynthesis of monoterpenes. Two hypotheses were formulated to understand the oxidation process during aging of the oleoresins: (i) a natural chemical oxidation of terpenes and (ii) an oxidation catalyzed by enzymes produced by microorganisms associated with the plant. The results suggested that terpinolene was most likely oxidized to p-cymene, which, in turn, was oxidized into p-cymen-8-ol during natural aging of the exudate due to abiotic factors.

In vitro activity of the essential oil from Hesperozygis myrtoides on Rhipicephalus (Boophilus) microplus and Haemonchus contortus

ABSTRACT Commercial antiparasitics have been the main tool to control parasites, but due to the resistance development, plant extracts have been widely investigated to find new molecules. The present study aimed to investigate the in vitro acaricide and anthelmintic activities of the essential oil from the aerial parts of Hesperozygis myrtoides (A.St.-Hil. ex Benth.) Epling, Lamiaceae. The essential oil was obtained by hydrodistillation analyzed by GC-FID and GC-MS. Four tests were conducted in vitro to screen the antiparasitic action of the essential oil. The evaluation on Rhipicephalus (Boophilus) microplus was performed with the adult immersion test at concentrations ranging from 0.391 to 25 mg/ml and the larval packet test from 3.125 to 100 mg/ml. For Haemonchus contortus the egg hatch test was performed from 0.012 to 25 mg/ml and the larval development test from 0.003 to 0.4 mg/ml. The LC50 and LC90 values were calculated by Probit. The main components identified in the essential oil were isomenthone (47.7%), pulegone (21.4%), limonene (7.7%), isomenthyl acetate (6.8%) and neoisomenthol (3.9%). In the larval packet test the LC50 and LC90 were 13.5 and 21.8 mg/ml, respectively. In egg hatch test, the LC50 and LC90 were 0.249 and 0.797 mg/ml, respectively, while in the larval development test were 0.072 and 0.167 mg/ml, respectively. This is the first report of the H. myrtoides evaluation against those parasites. The anthelmintic results proved its efficacy on H. contortus encouraging new research with a focus on their main bioactives.

Studies on the volatile fraction composition of three native Amazonian-Brazilian fruits: Murici (Byrsonima crassifolia L., Malpighiaceae), bacuri (Platonia insignis M., Clusiaceae), and sapodilla (Manilkara sapota L., Sapotaceae).

The volatile fraction of murici, bacuri and sapodilla are here studied because of their increasing interest for consumers, abundance of production in Brazil, and the general demand for new flavors and aromas. Their volatile profiles were studied by two High Concentration Capacity Headspace techniques (HCC-HS), Headspace Solid Phase Microextraction (HS-SPME) and Headspace Sorptive Extraction (HSSE), in combination with GC-MS. Murici volatile fraction mainly contains esters (38%), carboxylic acids (19%), aldehydes (11%), alcohols (14%), others (13%) and sulfur compounds; bacuri is characterized by terpenes (41%), non-terpenic alcohols (24%), esters (15%), aldehydes (6%), and others (12%); sapodilla consists of esters (33%), alcohols (27%), terpenes (18%) and others (21%). The GC-MS component co-elution was overcome by GC×GC-qMS. The adoption of modern analysis technologies afforded to achieve a better knowledge of the volatile fraction composition of these fruit pulps by increasing substantially the number of compounds identified.

Qualitative analysis of Copaifera oleoresin using comprehensive two-dimensional gas chromatography and gas chromatography with classical and cold electron ionisation mass spectrometry.

Improved separation of both sesquiterpenes and diterpenic acids in Copaifera multijuga Hayne oleoresin, is demonstrated by using comprehensive two-dimensional gas chromatography (GC×GC) coupled to accurate mass time-of-flight mass spectrometry (accTOFMS). GC×GC separation employs polar phases (including ionic liquid phases) as the first dimension (1D) column, combined with a lower polarity 2D phase. Elution temperatures (Te) of diterpenic acids (in methyl ester form, DAME) increased as the 1D McReynolds' polarity value of the column phase decreased. Since Te of sesquiterpene hydrocarbons decreased with increased polarity, the very polar SLB-IL111 1D phase leads to excessive peak broadening in the 2D apolar phase due to increased second dimension retention (2tR). The combination of SLB-IL59 with a nonpolar column phase was selected, providing reasonable separation and low Te for sesquiterpenes and DAME, compared to other tested column sets, without excessive 2tR. Identities of DAME were aided by both soft (30eV) electron ionisation (EI) accurate mass TOFMS analysis and supersonic molecular beam ionisation (cold EI) TOFMS, both which providing less fragmentation and increased relative abundance of molecular ions. The inter-relation between EI energies, emission current, signal-to-noise and mass error for the accurate mass measurement of DAME are reported. These approaches can be used as a basis for conducting of GC×GC with soft EI accurate mass measurement of terpenes, particularly for unknown phytochemicals.

7-hydroxycalamenene Effects on Secreted Aspartic Proteases Activity and Biofilm Formation of Candida spp.

BACKGROUND: The 7-hydroxycalamenenene-rich essential oil (EO) obtained from the leaves of Croton cajucara (red morphotype) have been described as active against bacteria, protozoa, and fungi species. In this work, we aimed to evaluate the effectiveness of 7-hydroxycalamenenene against Candida albicans and nonalbicans species. MATERIALS AND METHODS: C. cajucara EO was obtained by hydrodistillation and its major compound, 7-hydroxycalamenene, was purified using preparative column chromatography. The anti-candidal activity was investigated by minimum inhibitory concentration (MIC) and secreted aspartic proteases (SAP) and biofilm inhibition assays. RESULTS: 7-hydroxycalamenene (98% purity) displayed anti-candidal activity against all Candida species tested. Higher activity was observed against Candida dubliniensis, Candida parapsilosis and Candida albicans, showing MIC values ranging from 39.06 µg/ml to 78.12 µg/ml. The purified 7-hydroxycalamenene was able to inhibit 58% of C. albicans ATCC 36801 SAP activity at MIC concentration (pH 7.0). However, 7-hydroxycalamenene demonstrated poor inhibitory activity on C. albicans ATCC 10231 biofilm formation even at the highest concentration tested (2500 µg/ml). CONCLUSION: The bioactive potential of 7-hydroxycalamenene against planktonic Candida spp. further supports its use for the development of antimicrobials with anti-candidal activity. SUMMARY: Croton cajucara Benth. essential oil provides high amounts of 7-hydroxycalamenene7-Hydroxycalameneneisolated from C. cajucarais active against Candida spp7-Hydroxycalameneneinhibits C. albicans aspartic protease activity7-Hydroxycalamenene was not active against C. albicans biofilm formation. Figure.

Discrimination of pulp oil and kernel oil from pequi (Caryocar brasiliense) by fatty acid methyl esters fingerprinting, using GC-FID and multivariate analysis.

Pequi is an oleaginous fruit whose edible oil is composed mainly by saturated and monounsaturated fatty acids. The biological and nutritional properties of pequi oil are dependent on its composition, which can change according to the oil source (pulp or kernel). There is little data in the scientific literature concerning the differences between the compositions of pequi kernel and pulp oils. Therefore, in this study, different pequi genotypes were evaluated to determine the fatty acid composition of pulp and kernel oils. PCA and PLS-DA were applied to develop a model to distinguish these oils. For all evaluated genotypes, the major fatty acids of both pulp and kernel oils were oleic and palmitic acids. Despite the apparent similarity between the analyzed samples, it was possible to discriminate pulp and kernel oils by means of their fatty acid composition using chemometrics, as well as the unique pequi genotype without endocarp spines (CPAC-PQ-SE-06).

Effects of 7-hydroxycalamenene isolated from Croton cajucara essential oil on growth, lipid content and ultrastructural aspects of Rhizopus oryzae.

The leaves and bark of Croton cajucara, a shrub from the Amazon region, have been used in folk medicine to treat diabetes, malaria, and gastrointestinal and liver disorders. The essential oil from the leaves, rich in linalool, presented antileishmanial and antimicrobial activities. A chemotype of this species was found with an essential oil rich in 7-hydroxycalamenene. During our studies of the C. cajucara essential oil, we isolated 7-hydroxycalamenene at > 98 % purity. The minimum inhibitory concentration of 7-hydroxycalamenene against Absidia cylindrospora, Cunninghamella elegans, Mucor circinelloides, Mucor circinelloides f. circinelloides, Mucor mucedo, Mucor plumbeus, Mucor ramosissimus, Rhizopus microsporus, Rhizopus oryzae, and Syncephalastrum racemosum ranged from 19.53 to 2500 µg/mL. The reference drug used, amphotericin B, presented a minimum inhibitory concentration ranging from 0.085 µg/mL to 43.87 µg/mL. 7-Hydroxycalamenene also altered spore differentiation and total lipid content. Ultrastructural analysis by transmission electron microscopy showed significant alterations in the cellular structure of R. oryzae.

In vitro cytocidal effects of the essential oil from Croton cajucara (red sacaca) and its major constituent 7- hydroxycalamenene against Leishmania chagasi.

BACKGROUND: Visceral leishmaniasis is the most serious form of leishmaniasis and can be lethal if left untreated. Currently available treatments for these parasitic diseases are frequently associated to severe side effects. The leaves of Croton cajucara are used as an infusion in popular medicine to combat several diseases. Previous studies have demonstrated that the linalool-rich essential oil from C. cajucara (white sacaca) is extremely efficient against the tegumentary specie Leishmania amazonensis. In this study, we investigated the effects of the 7-hydroxycalamenene-rich essential oil from the leaves of C. cajucara (red sacaca) against Leishmania chagasi, as well as on the interaction of these parasites with host cells. METHODS: Promastigotes were treated with different concentrations of the essential oil for determination of its minimum inhibitory concentration (MIC). In addition, the effects of the essential oil on parasite ultrastructure were analyzed by transmission electron microscopy. To evaluate its efficacy against infected cells, mouse peritoneal macrophages infected with L. chagasi promastigotes were treated with the inhibitory and sub-inhibitory concentrations of the essential oil. RESULTS: The minimum inhibitory concentrations of the essential oil and its purified component 7-hydroxycalamenene against L. chagasi were 250 and 15.6 µg/mL, respectively. Transmission electron microscopy analysis revealed important nuclear and kinetoplastic alterations in L. chagasi promastigotes. Pre-treatment of macrophages and parasites with the essential oil reduced parasite/macrophage interaction by 52.8%, while it increased the production of nitric oxide by L. chagasi-infected macrophages by 80%. CONCLUSION: These results indicate that the 7-hydroxycalamenene-rich essential oil from C. cajucara is a promising source of leishmanicidal compounds.

Antioxidant and antimicrobial activities of 7-hydroxy-calamenene-rich essential oils from Croton cajucara Benth.

Croton cajucara is a shrub native to the Amazon region locally known as "sacaca". Two morphotypes are known: white and red "sacaca". The essential oils (EO) obtained by hydrodistillation from leaves of the red morphotype were, in general, rich in 7-hydroxycalamenene (28.4%-37.5%). The effectiveness of these EO regarding the antimicrobial activity against pathogenic microorganisms was initially investigated by the drop test method, showing significant inhibition zones. Among the microorganisms tested, the essential oils rich in 7-hydroxycalamenene were more effective against methicillin resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Mycobacterium tuberculosis, M. smegmatis, Mucor circinelloides and Rhizopus oryzae. The minimum inhibitory concentrations (MIC) of the oils were determined using the broth dilution assay. It was possible to observe that 7-hydroxycalamenene-rich oils presented high antimicrobial activity, with MIC of 4.76 × 10⁻³ µg/mL for MRSA, 4.88 µg/mL for M. tuberculosis, 39.06 µg/mL for M. smegmatis, and 0.152 µg/mL for R. oryzae and 3.63 × 10⁻8 µg/mL for M. circinelloides. The antioxidant activity of this EO suggests that 7-hydroxycalamenene provides more antioxidant activity according with EC(50) less than 63.59 µg/mL. Considering the bioactive potential of EOs and 7-hydroxycalamenene could be of great interest for development of antimicrobials for therapeutic use in treatment of bacterial and fungal infections in humans and/or veterinary practice.