Richardson A. de Almeida

An antimicrobial alkaloid and other metabolites produced by Penicillium sp. An endophytic fungus isolated from Mauritia flexuosa L. f.

The alkaloid glandicoline B (1) and six other compounds: ergosterol (2), brassicasterol (3), ergosterol peroxide (4), cerevisterol (5), mannitol (6) and 1-O-α-D-glucopyranoside (7) were isolated from Penicillium sp. strain PBR.2.2.2, a fungus from Mauritia flexuosa roots. The structures of the isolated metabolites were established by spectral analysis. MeOH extract of the fungal mycelium at 500 µg mL-1 exhibited antimicrobial activity against Staphylococcus aureus and the compound 1 at 100 µg mL-1 was active against S. aureus, Micrococcus luteus and Escherichia coli. The relationship between the bioactive properties of the fungus PBR.2.2.2 and those achieved for glandicoline B, as well the potential of this substance as bactericide is discussed.

DESREPLICAÇÃO DE ALCALOIDES APORFÍNICOS E OXOAPORFÍNICOS DE Unonopsis guatterioides POR ESI‑IT‑MS

The dereplication of aporphine and oxoaporphine alkaloids by direct infusion in ESI-IT-MSn system was applied for alkaloidal fractions of the Unonopsis guatterioides (Annonaceae). Its main advantage over other dereplication methods is the ability to quickly identify substances in complex mixtures without the use of coupled techniques and expensive databases. By only the fragmentation keys and comparison with literature data the aporphine alkaloids anonaine, asimilobine and nornuciferine were identified. The nornuciferine is being reported for the first time in Unonopsis. The oxoaporphine alkaloids liriodenine and lisycamine were identified in the alkaloidal fractions by comparison with the fragmentations of authentic samples.

An antimicrobial diketopiperazine alkaloid and co-metabolites from an endophytic strain of Gliocladium isolated from Strychnos cf. toxifera

From an endophytic strain of Gliocladium sp. isolated from the Amazonian plant Strychnos cf. toxifera, we obtained the diketopiperazine alkaloid cyclo-(glycyl-L-tyrosyl)-4,4-dimethylallyl ether (1), the steroids ergosterol (2), ergosterol peroxide (3), cerevisterol (4) and the citric acid (5). The AcOEt extract of the fermented broth by Gliocladium sp. showed potent activity against the cancer cell lines MDA-MB435 (human breast cancer cells), HCT-8 (human colorectal cancer cells) and SF-295 (human glioblastoma cancer cells). Compound 1 exhibited a strong antimicrobial activity against Micrococcus luteus at a concentration of 43.4 µM.

Direct infusion ESI‐IT‐MSn alkaloid profile and isolation of tetrahydroharman and other alkaloids from Bocageopsis pleiosperma maas (Annonaceae)

INTRODUCTION The Annonaceae family is known as a promising abundant source of secondary metabolites, especially annonaceous acetogenins, terpenoids and isoquinoline-derived alkaloids. Although widely investigated from the phytochemical viewpoint, this family still presents some largely unexplored genera, e.g. the Bocageopsis. OBJECTIVE To investigate the alkaloid content of Bocageopsis pleiosperma Maas using direct infusion electrospray ionisation ion trap tandem mass spectrometry (ESI-IT-MS(n)) analysis. METHODOLOGY Dichloromethane extracts of aerial parts were subjected to acid-base partitioning to yield the alkaloidal fractions. These fractions were analysed by direct infusion into a (+)ESI-IT-MS(n) system. The alkaloidal fraction from the leaves was also obtained on a large scale and subjected to chromatographic separation. RESULTS The tentative MS(n) -based identification of alkaloids in leaves, twigs and trunk bark showed that aporphine alkaloids were restricted to the leaves and twigs, tetrahydroprotoberberine alkaloids were only found in the twigs and trunk bark while benzylisoquinoline alkaloids were found in the leaves, twigs and trunk bark. Chromatographic separation of the leaf alkaloidal fraction yielded the aporphine alkaloids nornuciferine, asimilobine and isoboldine, the β-carboline alkaloid tetrahydroharman and some mixtures containing benzylisoquinoline and aporphine alkaloids, all described for the first time in the Bocageopsis genus. Furthermore, tetrahydroharman has not previously been reported in the Magnoliales order. CONCLUSION Direct infusion ESI-IT-MS(n) analysis of alkaloids allowed fast recognition of alkaloidal classes previously reported in the Annonaceae family, aiding the chromatographic step and allowing a selective isolation of compounds previously not identified in the Bocageopsis genus.

Chemotaxonomy of the Amazonian Unonopsis Species Based on Leaf Alkaloid Fingerprint Direct Infusion ESI-MS and Chemometric Analysis

Unonopsis (Annonaceae) is a neotropical genus constituted by nearly fifty species, with fifteen described in Brazil. In the state of Amazonas seven species are found, including U. guatterioides, which displays problems from the botanical viewpoint. Previous studies showed this genus as a promising source of aporphinoid alkaloids. In order to investigate the potential of the leaf alkaloid fingerprint for chemotaxonomic approaches, twelve Unonopsis specimens, representing five species commonly found in the state of Amazonas were subjected to acid-base partitioning to yield the respective alkaloidal fractions. These fractions were analysed by direct infusion electrospray ionization multiple stage mass spectrometry (ESI-MSn). The obtained data were treated through chemometric tools [principal components analysis (PCA) and hierarchical cluster analysis (HCA)]. Multivariate analysis pointed to aporphine, proaporphine and tetrahydroprotoberberine alkaloids as the responsible compounds for segregation of the investigated species, being these alkaloids tentatively identificated by multiple stage mass spectrometry. The alkaloid fingerprint along with multivariate analysis provided a simple and effective approach to differentiateUnonopsis species commonly found in the state of Amazonas.

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 β-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.

Isolation and amino acid sequencing by MALDI-TOF-MS/MS of a novel antimicrobial anionic peptide from the skin secretion of Osteocephalus taurinus (Anura, Hylidae)

By means of chromatographic techniques, a novel anionic peptide, named otacidin, was isolated from the skin secretions of tree Brazilian anurans Osteocephalus taurinus. The de novo sequencing of the amino acids was performed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS/MS) analyses. The antimicrobial potential of this novel metabolite was evaluated against Escherichia coli and Pseudomonas aeruginosa, being observed minimum inhibitory concentration (MICs) of 37.4 and 78.4 mM, respectively. This work is just the second report of an antimicrobial anionic peptide from an amphibian.

Solid Phase Extraction of Phospholipids from Brazil Nut (Bertholletia excelsa) and Their Characterization by Mass Spectrometry Analysis

The Brazil nut (Bertholletia excelsa - Lecythidaceae) is considered a product with high economic value, being a food widely appreciated for its nutritional qualities. Although previous studies have reported the biochemical composition of Brazil nut oil, the knowledge regarding the phospholipid composition exhibits a disagreement: the composition of fatty acids present in the structures of phospholipids is reported as being different from the composition of the free fatty acids present in the oil. In this work, solid phase extraction (SPE) was employed to provide a fast extraction of the phospholipids from Brazil nuts, in order to compare the phospholipid profile of the in nature nuts and their fatty acids precursor present in the oil. The major phospholipids were characterized by mass spectrometry approach. Their fragmentation pattern through direct infusion electrospray ionization ion-trap tandem mass spectrometry (ESI-IT-MS 2 ) proved to be useful to unequivocal characterization of these substances. High resolution (HR) experiments through ESI using a quadruple time of flight mass spectrometry (QTOF) system were performed to reinforce the identifications.

Constituintes químicos do caule de Protium hebetatuml (Burseraceae)

Protium is the largest genus in the Burceraceae family, which comprises about 146 species, of which a small number has been studied from the phytochemical point of view. In this work the terpenoids α- and β-amyrin, the steroids campesterol, stigmasterol and sitosterol and the coumarin scopoletin were isolated from the stem of Protium hebetatuml. The structures of these substances were identified by NMR, MS, IV and comparison with spectral data from the literature and with authentic samples.

Remela de cachorro (Clavija lancifolia Desf.) fruits from South Amazon: Phenolic composition, biological potential, and aroma analysis

Remela de cachorro (Clavija lancifolia Desf.) is an Amazonian native fruit consumed specially in the Purus microregion. Because of its rarity, restricted consumption, and the lack of knowledge about its chemical composition, remela de cachorro fruit was studied in relation to its phenolic and aroma constitution. Using liquid chromatography tandem mass spectrometry (LC-MS/MS), 11 compounds (flavonoids and its glucosides along with organic acids) were tentatively identified by fragmentation patterns. A previously validated method was applied to quantify common antioxidant compounds in the raw pulps, for which kaempferol was the main compound. Gas chromatography mass spectrometry (GC-MS) with headspace solid-phase microextraction (HS-SPME) was employed to assess the aroma composition of remela de cachorro fruit. A total of 27 volatile organic compounds (VOCs) were identified for this fruit, for which benzaldehyde and linalool were the main VOCs. Furthermore, biological activities, such as antioxidant capacity (ABTS, DPPH, and ORAC methods), cytotoxicity, and α-glucosidase and lipase inhibitions of the hydroalcoholic extract of remela de cachorro fruit were evaluated. In vitro biological assays revealed the potential of this fruit as a bioactive food that should be further studied and explored in Amazonian products.