Chemical composition and antioxidant activity of the essential oil of Renealmia alpinia (Rottb.) Maas.

Renealmia alpinia (Rottb.) Maas was collected in Serra do Tepequém, municipality of Amajari, state of Roraima, Brazil. The essential oil was obtained from the fresh leaves by hydrodistillation using a Clevenger apparatus and analysed using GC-FID and GC-MS. The oil provided a yield of 0.6% (w/w), which, in the analysis of its contents, presented a higher concentration of sesquiterpenes, with α-phellandrene (23.10%), 16-oxo-8(17),12(E)-labdadien-15-oic acid (17.05%), ß-caryophyllene (10.28%), valencene (5.27%) and allo-aromadendrene (3.52%) being the most abundant. The antioxidant activity of the essential oil was determined using two methods, and indicated significant activity by both. Using the DPPH method, the essential oil presented an IC50 of 1.470 ± 0.0264 mg.L1 and an inhibition of the ß-carotene/linoleic acid oxidation system of 76.43 ± 0.80%.

Bioactive compounds of the Opuntia monacantha fruit.

Opuntia monacantha is a Cactaceae found in regions with few nutrients and water. This study aimed to identify bioactive compounds in the fruit of O. monacantha in the southern region of Brazil. In the fruit of O. monacantha, five phenolic compounds were identified: protocatechuic acid, ferulic acid, p-coumaric acid, catechin and quercetin. The ferulic acid and catechin were found in higher concentration in the fruit. The terpenes α-amyrin, ß-amyrin, oleanolic acid and cycloartenol were also identified in the hexane fractions of the fruit. Unsaturated fatty acids were found in the fruit seed, with the highest concentration of linoleic acid (69.0%).

Ultra-high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry and molecular networking analysis to investigate the chemodiversity of bioactive extracts of Annona jahnii Saff. fungi from the Brazilian Amazon.

RATIONALE: Annona species are of interest for the isolation of bioactive molecules; however, studies of Annona jahnii Saff. are limited. The exploration of bioactive metabolites of endophytes isolated from this species is unprecedented and allows the preservation of the host plant, in addition to enabling the discovery of compounds with promising biological activities. METHODS: Ethyl acetate extracts from the cultured media of five fungi were obtained. The antioxidant capacity of the extracts was measured using the 1,1-diphenyl-2-picrylhydrazyl free radical method. Antimicrobial activity was determined using the microdilution method in broth in 96-well plates. The exploration of the metabolic profile of the extracts and dereplication of the compounds were performed using ultra-high-performance liquid chromatography/electrospray ionization/tandem mass spectrometry (UHPLC/ESI-MS/MS) combined with analysis using molecular networking (MN). RESULTS: A total of 1818 MS features were detected in the five selected extracts, of which 39 compounds were putatively identified. The secondary metabolites with the highest abundance were alkaloids, naphthopyrons, and cytochalasins. Other secondary metabolites include fumonisins, coumarin, and a meroterpenoid. Most of these compounds are related to specific biological properties such as antioxidant, anti-inflammatory, antimicrobial, antiviral, and antitumor activities. Extracts F398 and F403 showed inhibitory activity of the four pathogens tested. Extracts F475 and F506 did not inhibit the growth of Staphylococcus aureus, and F407 did not inhibit the growth of Escherichia coli in addition to having potent antioxidant activity, with IC50 values of 10 µg/mL or less. CONCLUSIONS: The use of UHPLC/ESI-MS/MS data combined with MN proved useful in the dereplication of bioactive molecules of complex extracts that are still unexplored. These initial investigations should significantly assist in further research and increase the efficiency and speed in the discovery of new sources of secondary metabolites and new natural products.

Molecular network-guided chemical profile and mass spectrometry, volatile compounds, and antimicrobial activity of Scaptotrigona depilis propolis.

RATIONALE: Propolis has a great diversity in its composition due to numerous factors; therefore, each study is an important contribution to the knoFwledge of its composition and biological action. The objective of this study was to determine the chemical profile and biological activity of propolis produced by Scaptotrigona depilis. METHODS: Extracts with 70% ethanol (EPE70) and with cereal alcohol (CAPE) were elaborated, and then characterized using UHPLC-ESI(+)-MS/MS. Volatile compounds were extracted and then characterized using gas chromatography mass spectrometry (GC-MS). In addition, antimicrobial activities were verified against resistant strains. RESULTS: The volatile compounds of propolis predominantly consist of sesquiterpenes. Using the exploratory metabolomic approach, compounds of different classes were putatively identified in the ethanolic extracts, of which the most representative were terpenes, and some of the sesquiterpenes identified among the volatiles were also detected. The extracts were shown to be active against Escherichia coli and Staphylococcus aureus bacteria with a minimum inhibitory concentration (MIC) of 0.5 and 1.0 mg mL-1 , respectively. CONCLUSIONS: The molecular network approach proved to be determining the chemical profile of S. depilis propolis rapidly and accurately, and led to the identification of lipophilic compounds. The identification of compounds using GC-MS and UHPLC-ESI(+)-MS/MS is complementary and useful for the characterization of propolis.

Chemical Composition and Cytotoxic Evaluation of the Essential Oil of Phyllogonium viride (Phyllogoniaceae, Bryophyta).

The present study aimed to determine the chemical composition and biological activity of the essential oil obtained from Phyllogonium viride Brid. (Phyllogoniaceae, Bryophyta), whose samples were collected in southern Brazil. For the first time, the cytotoxic activity of the essential oil of P. viride in breast and colorectal tumor cells (MCF-7 and HCT-116) was evaluated, as well as the cytotoxic potential of this oil in non-tumoral cells of human immortalized keratinocytes (HaCaT) via MTT assay. The compounds majorly found in P. viride essential oil were ß-bazzanene (20.30 %), ß-caryophyllene (17.06 %), ß-chamigrene (14.02), and germacrene B (11.72 %). Treatment with P. viride essential oil in the different tested cell lines did not induce any toxicity in most of the tested concentrations. These data contribute to generating new scientific information about this understudied plant species. Furthermore, the chemical characterization of the compounds present in the essential oil of P. viride can lead to greater elucidation of its biotechnological potential.

Identification of lipophylic constituents of the nest of Frieseomelitta silvestrii (FRIESE, 1902).

Bees are becoming more and more valued for the extremely important role they play in ecological communities, especially for their pollinating action. The state of Roraima, Brazil has areas of native vegetation and variety of stingless bees, and this potential is still untapped. The objective of this study was to determine the chemical composition of materials collected from the nests of Frieseomelitta silvestrii (FRIESE, 1902), identified in São Luiz, in Roraima state, Brazil. The chemical composition of the collected material was determined by gas chromatography coupled to mass spectrometry (GC-MS). The dichloromethane extracts of propolis, cerumen threads and resin present in the stingless bee nest presented differentiated profiles with the occurrence of low polarity compounds.

Cytotoxic Activity of Cunila angustifolia Essential Oil.

The Cunila angustifolia essential oil was obtained from fresh leaves by hydrodistillation and analyzed by GC-FID and GC-MS to determine its chemical composition. The essential oil presented pulegone (29.5 %) and isomenthol (27.0 %) as major components, and other compounds such as menthone (8.6 %), neomenthol (7.2 %), menthyl acetate (2.5 %) and caryophyllene oxide (2.0 %) were identified. The cytotoxic activity of the essential oil was evaluated by MTS assay, with the human cancer cell lines of the lung (A549), breast (MCF-7) and skin melanoma (SK-Mel-28). The assay showed the highest selectivity, to MCF-7 cell lines, with IC50 equal to 34.0 µg mL-1 , low selectivity for SK-Mel-28 cell lines, with IC50 equal to 279.9 µg mL-1 , and no mortality to A549 cell lines.

Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens

Abstract Despite recent advances in food production technology, food-borne diseases (FBD) remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil), Rosmarinus officinalis L. (rosemary), Origanum majorana L. (marjoram), Mentha × piperita L. var. Piperita (peppermint), Thymus vulgaris L. (thyme) and Pimpinella anisum L. (anise) against C. perfringens strain A. Chemical compositions of the oils were determined by GC–MS (gas chromatography–mass spectrometry). The identities of the isolated compounds were established from the respective Kováts indices, and a comparison of mass spectral data was made with those reported earlier. The antibacterial activity was assessed from minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the microdilution method. Minimum inhibitory concentration values were 1.25 mg mL-1 for thyme, 5.0 mg mL-1 for basil and marjoram, and 10 mg mL-1 for rosemary, peppermint and anise. All oils showed bactericidal activity at their minimum inhibitory concentration, except anise oil, which was only bacteriostatic. The use of essential oils from these common spices might serve as an alternative to the use of chemical preservatives in the control and inactivation of pathogens in commercially produced food systems.

Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens.

Despite recent advances in food production technology, food-borne diseases (FBD) remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil), Rosmarinus officinalis L. (rosemary), Origanum majorana L. (marjoram), Mentha × piperita L. var. Piperita (peppermint), Thymus vulgaris L. (thyme) and Pimpinella anisum L. (anise) against C. perfringens strain A. Chemical compositions of the oils were determined by GC-MS (gas chromatography-mass spectrometry). The identities of the isolated compounds were established from the respective Kováts indices, and a comparison of mass spectral data was made with those reported earlier. The antibacterial activity was assessed from minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the microdilution method. Minimum inhibitory concentration values were 1.25mgmL(-1) for thyme, 5.0mgmL(-1) for basil and marjoram, and 10mgmL(-1) for rosemary, peppermint and anise. All oils showed bactericidal activity at their minimum inhibitory concentration, except anise oil, which was only bacteriostatic. The use of essential oils from these common spices might serve as an alternative to the use of chemical preservatives in the control and inactivation of pathogens in commercially produced food systems.

Antibacterial mode of action of the hydroethanolic extract of Leonotis nepetifolia (L.) R. Br. involves bacterial membrane perturbations.

ETHNOPHARMACOLOGICAL RELEVANCE: Leonotis nepetifolia (L) R. Br., Lamiaceae, a pantropical shrub, popularly known in Brazil as "cordão-de-frade", "rubim", is reportedly used in Brazilian ethnomedicine as well as in different countries in the treatments of ailments such as infections, inflammations, wounds, stomach disorders, among others. AIM OF THE STUDY: To evaluate its potential cytotoxicity and antibacterial mode of action of the hydroethanolic extract of L. nepetifolia (HELn) leaves, including phytochemical analysis. MATERIALS AND METHODS: The cytotoxicity of HELn was investigated by Alamar blue assay, using CHO-K1 cells. Antibacterial activity of HELn was tested by broth microdilution methods against a panel of bacteria of clinical interest. The mode of action of L. nepetifolia was studied by targeting bacterial membranes. Phytochemical analysis was performed by determining total secondary metabolites with spectrophotometric assays and HPLC. RESULTS: HELn is not cytotoxic in the in vitro evaluation (IC50>200 µg/mL). It demonstrated a good spectrum of antibacterial activity with major activity against Shigella flexneri, Enterococcus faecalis, Staphylococcus aureus and Bacillus subtilis with MIC=6.25 µg/mL, Helicobacter pylori with MIC of 25 µg/mL and Streptococcus pyogenes with MIC of 50 µg/mL. Its mode of action is associated, at least partly, with changes in the permeability of bacterial membranes, as evidenced by the increased entry of hydrophobic antibiotics in Shigella flexneri and intense efflux of K(+) and nucleotide leakage in E. faecalis and Shigella flexneri. In addition, the presence of phenols, flavonoids and carotenoids, described in the literature to possess antibacterial effects, were detected in the composition of HELn, with high phenol content (11.55%), especially the flavonoids (6.47%). CONCLUSION: The results indicate that HELn has low cytotoxicity and potent antibacterial activity. It is bacteriostatic in nature, possibly acting at the level of bacterial membranes, especially on the cytoplasmic membrane and outer membrane, thus supporting its popular use in infectious processes. In addition, the presence of phenols, flavonoids, carotenoids, fatty acids and steroids, described in the literature as possessing antimicrobial activity, were detected in the composition of HELn.

Chemical composition and antimicrobial evaluation of the essential oils of Bocageopsis pleiosperma Maas.

Essential oils from the leaves, twigs and barks of Bocageopsis pleiosperma Maas were obtained by using hydrodistillation and analysed by using gas chromatography coupled to mass spectrometry. Several compounds (51) were detected and identified, being ß-bisabolene the main component in all aerial parts of the plant, with higher concentration in the leaves (55.77%), followed by barks (38.53%) and twigs (34.37%). In order to increase the biological knowledge about the essential oil of Bocageopsis species, antimicrobial activities were evaluated against the microorganisms Escherichia coli, Staphylococcus epidermidis, Enterobacter aerogenes, Candida tropicalis, Candida dubliniensis, Candida glabrata and Candida albicans. The essential oil obtained from the barks exhibited a moderate effect against S. epidermidis ATCC 1228 (MIC = 250 µg/mL), while the other oils did not exhibit antimicrobial activity. These results represent the first report about the chemical composition of B. pleiosperma and the first antimicrobial evaluation with a Bocageopsis species.

Evaluation of the toxicity and antimicrobial activity of hydroethanolic extract of Arrabidaea chica (Humb. & Bonpl.) B. Verl.

ETHNOPHARMACOLOGICAL RELEVANCE: Arrabidaea chica (Bignoniaceae) is a vine native to the Amazon Rainforest, popularly known as "crajiru" and whose infusion and decoction of the leaves are used to treat diseases such as gastric ulcers, inflammations, infections, anemia, herpes, jaundice among others. It is also used as a natural dye. This work aimed to evaluate the in vitro and in vivo toxicity, antimicrobial activity including analysis of chemical constitution of the hydroethanolic extract of the leaves of Arrabidaea chica (HEAc). MATERIALS AND METHODS: Acute and subchronic toxicity of HEAc was evaluated in mice and rats, respectively, and by Alamar blue (cytotoxicity assay) using CHO-K1 cells. Antimicrobial activity of HEAc was tested by broth microdilution method using a panel of bacteria and yeast of clinical interest. The preliminary phytochemical analysis of HEAc was performed by electrospray ionization mass spectrometry [ESI(+)-MS]. Secondary metabolites were quantified by colorimetric methods. RESULTS: When administered in vivo at doses up to 3000 mg/kg v.o., HEAc did not cause any signs and symptoms of acute toxicity in mice and no cytotoxicity in CHO-K1 cells. Administration for 30 days caused leukocytosis (200 mg/kg) and reversible reductions in non-dose dependent of body weight, total weight gain and feed intake in rats given 200mg/kg and 500 mg/kg of HEAc, but were not accompanied by behavioral and clinical changes (laboratory and histopathological) that may have demonstrated evidences of subchronic toxicity HEAc demonstrated a pronounced activity against Helicobacter pylori (MIC=12.5 µg/mL) and moderate activity against Enterococcus faecalis (MIC=100 µg/mL) in broth microdilution. Preliminary phytochemical analysis of HEAc by colorimetric methods revealed that mainly the presence of phenolic compounds (16.6%), especially flavones and flavonols (4.02%). [ESI(+)-MS] fingerprint analyses of HEAc revealed the presence of 3-deoxyanthocyanidins and kaempferol. CONCLUSION: Our data provide evidence that HEAc is safe and can be useful in infections related to Helicobacter pylori and Enterococcus faecalis. Phytochemical analysis revealed the predominant presence of flavones and flavonols, possibly involved in the antimicrobial action of HEAc.

Chemical changes associated with the invasion of a Melipona scutellaris colony by Melipona rufiventris workers.

Wax constituents produced by worker bees and the chemistry of the nest batumen (mixture of wax, mud, and floral materials) in a Melipona scutellaris colony changed when it was invaded by Melipona rufiventris workers. Gas chromatography/mass spectrometry analyses showed that after invasion, the M. scutellaris workers of the invaded colony produced waxes with higher relative abundance of triacontanyl acetate and decreased the amounts of n-alkanes and n-9-alkenes. On the other hand, waxes from M. rufiventris workers displayed few changes. The change in the composition of the M. scutellaris waxes chemically differentiates that species from the M. rufiventris invader workers. Comparative analyses of batumens samples from pure and invaded colonies revealed greater amounts of terpenes and phenolic derivatives in the batumen from the invaded colony. This is the first report on the chemical characterization of batumens from stingless bees.

Pollination by sexual mimicry in Mormolyca ringens: a floral chemistry that remarkably matches the pheromones of virgin queens of Scaptotrigona sp.

The chemical composition of some volatile (2-heptanol) and nonvolatile constituents (a homologous 9-alkene/alkane series) of Mormolyca ringens flowers and Scaptotrigona sp. queen waxes (homologous 9-alkene/alkane series) and cephalic extracts (homologous series of 2-alkanols, including 2-heptanol) involved with the pseudocopulation or sexual mimicry in Orchidaceae pollination is compared. The similarity in chemical composition of flowers and insects is assigned to the chemically induced copulatory activity in Scaptotrigona males.

The chemistry of pollination in selected Brazilian Maxillariinae orchids: floral rewards and fragrance.

We report the chemical composition of the floral rewards and the fragrance of 10 Maxillariinae (Orchidaceae) species. The species that offer rewards (labellar secretions) are usually scentless, the rewards being collected by bees. Chemical analyses revealed that the major chemical class of compounds present in the labellar secretions are triterpenoids. The rewardless Maxillariinae flowers were usually scented, and chemical analyses of their volatiles revealed that they were composed of mono and sesquiterpenoids.

Sexual mimicry in Mormolyca ringens (Lindl.) Schltr. (Orchidaceae: Maxillariinae).

BACKGROUND AND AIMS: Pollination through sexual mimicry, also known as pseudocopulation, has been suggested to occur in some genera of the Neotropical orchid subtribe Maxillariinae. However, it has been demonstrated so far only for Trigonidium obtusum. This study reports and illustrates pollination through sexual mimicry in Mormolyca ringens. METHODS: A total of 70 h were dedicated to the observation of flowers and pollinator behaviour, which was photographically recorded. Flower features involved in pollinator attraction were studied using a stereomicroscope and by SEM analyses. Preliminary observations on the plant breeding system were made by manually self-pollinating flowers. The chemical composition of the fragrance volatiles was determined by GC/MS analysis. KEY RESULTS: The flower features of M. ringens parallel those of other pseudocopulatory flowers. The labellum shape and indument are reminiscent of an insect. Sexually excited drones of Nannotrigona testaceicornis and Scaptotrigona sp. (both in the Apidae: Meliponini) attempt copulation with the labellum and pollinate the flower in the process. In both bee species, the pollinarium is attached to the scutellum. Pollinator behaviour may promote some degree of self-pollination, but preliminary observations indicate that M. ringens flowers are self-incompatible. Flowers are produced all the year round, which ties in with the production of bee males several times a year. The phylogenetic relationships of M. ringens are discussed and a number of morphological and phenological features supporting them are reported. CONCLUSIONS: It is expected that further research could bring to light whether other Maxillariinae species are also pollinated through sexual mimicry. When a definitive and robust phylogeny of this subtribe is available, it should be possible to determine how many times pseudocopulation evolved and its possible evolutionary history.

Chemical analysis and antifungal activity of the essential oil of Calea clematidea.

The chemical composition of the essential oils of Calea clematidea Baker obtained by hydrodistillation of the leaves and flowers was analysed by GC and GC/MS and the oils were assayed for their antifungal activities. The essential oil of the leaves showed a high content of a new natural epoxy terpenoid, named clemateol (ca. 70 %), with minor amounts of o-vanillin (6.5 %), spathulenol (4.2 %), alpha-terpinene (4.0 %), germacrene B (2.9 %), yomogi alcohol (1.8 %), ( E)-caryophylene (1.7 %), m-cymenene (1.6 %), and alpha-gurjunene (1.5 %), while the essential oil of the flowers was characterized by a higher content of thymol methyl ether (ca. 80 %), with minor amounts of clemateol (4.8 %) and o-cymene (4.7 %). The antimicrobial activity of the oils was also evaluated against dermatophytes for their possible use in pharmaceutical preparations for topical applications. The oil of the leaves (MIC > 3.57 mg/ml), clemateol (MIC > 1.52 mg/ml), and the alcohol 2 (MIC > 2.82 mg/ml) showed a moderate antifungal activity against Trichophyton tonsurans, Trichophyton rubrum, Trichophyton menthagrophytes var. i nterdigitale, Epidermophyton floccosum, Microsporum gypseum, Microsporum canis and Microsporum nanum.