Elzalina R. Soares

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.

Triterpenes and flavonoids from the roots of Mauritia flexuosa

Mauritia flexuosa L. f., Arecaceae, is an endemic species of South America. This species was studied with the intent to isolate the constituents of its roots. After the fractionation of the n-hexane and methanolic extracts from the roots of M. flexuosa, six triterpenes were obtained: friedelin, taraxerone, lupenyl acetate, lupenone, betulin and betulinic acid, along with three flavonoids: rutin, quercitrin and quercetin. All the compounds were identified by analysis of NMR and MS data and comparison with the literature. All those compounds are been reported for the first time in Mauritia, and the chemosystematic significance of the flavonoids isolated in this genus is discussed.

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.

Mauritic acid: a new dammarane triterpene from the roots of Mauritia flexuosa L.f. (Arecaceae)

A new dammarane triterpene named mauritic acid (1) was isolated from the roots of Mauritia flexuosa L.f. The complete structural assignment of this new compound was elucidated from spectroscopic methods. Moreover, this compound was evaluated for its cytotoxicity against human cancer cell lines (OVCAR-8, PCM3, NCIH358M and different leukaemia cell strains). The mauritic acid presented significant cytotoxicity against OVCAR-8, PCM3 and NCIH358M cell lines with IC50 3.02, 2.39 and 6.19 μM, respectively. The triterpenes 1 and 2 were also tested for their antimicrobial activity against 15 strains of microorganisms, including fungi and bacteria, with the best minimal inhibitory concentration values ranging from 50.8 to 203.5 μM.

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 constituents of Penicillium chrysogenum, an endophytic fungus from Strychnos toxifera

Strychnos toxifera is a poisonous plant used by Amazon indians in the manufacture of curare poison [1]. Its toxicity is clue to indole alkaloids, which are the major constituents of this poison [2]. Endophytes are considered outstanding and underexplored sources of novel chemically diverse and bioactive compounds. These microorganisms can be detected at a particular moment within the tissues of apparently healthy plant hosts, and they have been found in all plant species examined to date [3]. As they occupy unique biological niches, the complex web of interactions with other endophytes and with the host might give rise to new chemical diversity and bioactive compounds [4]. In the course of screening for biologically active agents from Amazonian endophytic fungi [5], Penicillium chrysogenum, an endophytic fungus from the trunk of S. toxifera, was chosen for further phytochemical investigation. The MeOH extract of the mycelial mass from P. chrysogenum was subjected to chromatographic separation to afford four steroids [6] [ergosterol (1), brassicasterol (2), ergosterol peroxide (3), and cerevisterol (4)], two aromatic acids [7] [cinnamic acid (5) and p-hydroxybenzoic acid (6)], and three mycotoxins [8] [kojic acid (7), penicillic acid (8), and patulin (9)]. These compounds were obtained and characterized by a comparison of their physical and spectral data (UV, IR, NMR and MS), with values in the literature. S. toxifera was collected from Manaus, Brazil in July, 2008. The strain of P. chrysogenum was obtained, purified, and identified from the healthy tissues of the trunk using a previous methodology [9]. After cultivation in liquid media [5], the mycelial mass (1.1 kg) was extracted with MeOH (3 500 mL) at room temperature, and a MeOH extract (30.4 g) was obtained upon concentration under reduced pressure. The MeOH extract was chromatographed over silica gel (600 g, 70–230 mesh) using n-hexane containing increasing amounts of EtOAc to obtain nine fractions. Fraction 1 (321.7 mg) was purified on a silica gel column with n-hexane–CHCl3 with increasing gradient, yielding 1 (22 mg), 2 (7 mg), 3 (12 mg), and 4 (9 mg). Fraction 5 (507 mg) was subjected to silica gel chromatography with CHCl3–MeOH with increasing gradient, yielding 5 (4 mg), 6 (11 mg), 7 (89 mg), 8 (9 mg), and 9 (5 mg).

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.

Chemical composition and antimicrobial activity of the essential oils of Onychopetalum amazonicum R.E.Fr.

Abstract The essential oils from leaves, twigs and trunk bark of Onychopetalum amazonicum R.E. Fr. (Annonaceae), obtained by hydrodistillation, were analysed by GC and GC–MS, and also were evaluated for in vitro antimicrobial activity. Forty-one compounds, which correspond to 75.0–92.2% of the oil components, were identified. Major compounds were sesquiterpenes, including (E)-caryophyllene, caryophyllene oxide, spathulenol, α-gurjunene, allo-aromadendrene and α-epi-cadinol. The oils were evaluated for antimicrobial activities against four bacteria strains and five pathogenic fungi. The oil of the trunk bark exhibited good activity against Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 10538 and Kocuria rhizophila ATCC 9341, with a minimal inhibitory concentration of 62.5 μg/mL. The essential oil composition and the antimicrobial evaluation are reported for the first time for the genus Onychopetalum.