Marcelo Francisco de Araújo

Antifungal activity of a novel quercetin derivative bearing a trifluoromethyl group on Candida albicans

In this study, a novel quercetin derivative bearing a trifluoromethyl group was synthesized by the nucleophilic aromatic substitution reaction between rutin and 2-chloro-5-(trifluoromethyl)-1,3-dinitrobenzene in basic medium. This synthetic quercetin showed antifungal activity against Candida albicans cultures. The results indicated a remarkable increase in the biological activity of this compound as compared to rutin.

Hirtinone, a Novel Cycloartane-Type Triterpene and Other Compounds from Trichilia hirta L. (Meliaceae)

One novel triterpene cycloartane-type, named hirtinone (1), six protolimonoids – nilocitin (2), dihydronilocitin B (3), melianone epimers (4) and (5), piscidinol A (6) and melianone lactone (7), one tertranortriterpenoid, hirtin (8), and one sesquiterpene, spathulenol (9), were identified in the fruits of Trichilia hirta. The structures were established by 1D and 2D NMR (1H and 13C-NMR, DEPTQ, 1H-1H-COSY, 1H-1H-NOESY, HSQC and HMBC), high resolution mass spectroscopy (HR-ESI-MS) and infrared (IR) spectral data.

Ouratea genus: chemical and pharmacological aspects

Ouratea and the other genera of the Ochnaceae family are a rich source of flavonoids and biflavonoids. These can be used as chemotaxonomic markers of Ouratea. Some biflavonoids, as well as extracts of the Ouratea species show important biological activities, such as anti-tumour, antiviral, vasodilation, antimicrobial and DNA topoisomerase inhibition. On the other hand species of this genus are used in folk medicine for gastric distress, dysentery, and diarrhea; as an astringent, a tonic, and for the treatment of inflammation-related diseases. The information collected in this review attempts to summarise the phytochemical and biological activities studied in Ouratea species that may be helpful to guide researches, to undertake further investigation concerning the common properties of Ouratea species and evaluation as a source of active compounds.

Other compounds isolated from Simira glaziovii and the ¹H and 13C NMR chemical shift assignments of new 1-epi-castanopsol

A new triterpene, 1-epi-castanopsol, besides eleven known compounds: sitosterol, stigmasterol, campesterol, lupeol, lupenone, simirane B, syringaresinol, scopoletin, isofraxidin, 6,7,8-trimethoxycoumarin and harman, were isolated from the wood of Simira glaziovii. The structures of the known compounds were defined by 1D, 2D 1H, 13C NMR spectra data analyses and comparison with literature data. The detailed spectral data analyses allowed the definition of the structure of the new 1-epi isomer of castanopsol and performance of 1H and 13C NMR chemical shift assignments.

Simiranes A and B: erythroxylanes diterpenes and other compounds from Simira eliezeriana (Rubiaceae)

The first phytochemical study of Simira eliezeriana Peixoto (Rubiaceae) allowed the isolation and structural determination of two new diterpenes named simirane A [(5R,6R,8R,9R,10S,11S,13S)-6β,11β-dihydroxy-2,4(18),15-erythroxylatrien-1-one] (1) and simirane B [(5S,8R,9R,10S,11S,13S)-11β-hydroxy-2,4(18),15-erythroxylatrien-1-one] (2), together with seven known compounds: sitosterol (3), stigmasterol (4), campesterol (5), coniferaldehyde (6), vanillin (7), pinoresinol (8) and harman (9) from the bark of the plant. The structures of the compounds were established on the basis of spectroscopic methods, including 1-D and 2-D NMR, HRESI-MS and CD analysis and comparisons with available literature data of known compounds.

Chemical constituents from Swartzia apetala Raddi var. glabra and evaluation of their antifungal activity against Candida spp.

From the hexanic extract of the stem from Swartzia apetala Raddi var. glabra were isolated one stilbene (1), one flavanone (2), one pterocarpan (3), one triterpene (4) and a mixture of three steroids (5 to 7). The crude extract and the compounds isolated were submitted to evaluation of the antifungal activity against nine yeast standard ATCC of the Candida genus. Among the compounds only the triterpene (4) and the mixture of steroids (5 to 7) showed no activity. The structures of the compounds were determined by spectral data analysis of GC/MS and 1H and 13C NMR (1D and 2D experiments), as well as comparison with literature values.

New triterpene glycoside and other chemical constituents from the leaves of Swartzia apetala Raddi var. glabra.

A new triterpene saponin (1) was isolated from a methanol extract of Swartzia apetala Raddi var. glabra, together with the flavonoids mauritianin (2), kaempferol (3) and the triterpene saponin β-D-glucopyranosyl 3β-hydroxy-olean-12-en-28-oate (4). These compounds were characterised on the basis of their spectral data, mainly one-dimension (1D; 1H, 13C, APT) and two-dimension (2D; 1H-1H-COSY, HMQC and HMBC) nuclear magnetic resonance (NMR) and HR-ESI-MS, and comparison with values in the literature. The analysis by HR-ESI-MS showed a mass compatible with that of triterpene saponin 1. This proposal was supported by molecular modelling. LC-HR-ESI-MS experiment was also used to evaluate the purity of 1 and allowed to speculate about the possibility of the presence of 5 in very small quantity. The extract and four compounds were assayed for antifungal activity against nine strains of Candida spp.

Proposed anti-HSV compounds isolated from Simira species

Abstract Secondary metabolites isolated from Simira eleiezeriana and Simira glaziovii were evaluated against herpes simplex virus (HSV-1) and (HSV-2). The 50% effective concentrations values (EC50) were calculated from the dose-response curve and the selectivity index (SI) against the virus. The physicochemical data LogP, (PSA), (NRB), (HBA) and (HBD) were obtained using Marvin Sketch. Among the tested compounds, conipheraldeyde, harman and simirane A showed better results with EC50 6.39; 4.90; 4.61 µg/mL and SI 78.3; 11.8; 7.01, respectively, for HSV-1, and EC50 41.2; 71.8; 3.73 µg/mL and SI 12.1; 24.7; 8.7, respectively, for HSV-2. The percentage of inhibition (PI) obtained for HSV-1 were higher than 60%, and for HSV-2 these compounds showed PI > 90%. The physical chemical data showed that the most active compounds satisfy the attributes for drugs with good oral bioavailability.

Two New Labdane-type Diterpenoids and others Compounds from Conchocarpus cyrtanthus (Rutaceae)

Two new labdane-type diterpenes called 16-hydroxylarixol (1) and 16-hydroxy-7-labden-6-one (2) were isolated from Conchocarpus cyrtanthus, along with three coumarins, seselin (3), xantoxiletin (4), luvangetin (5); the alkaloid dictamin (6); six steroids, -sitosterol (7), stigmasterol (8), campesterol (9), 7-hydroxy--sitosterol (10), 7-hydroxy-stigmasterol (11) and 7-hydroxy-campesterol (12); three diterpenes, manool (13), 16-hydroxymanoiloxide (14), and 16-hydroxy-13-epi-manoyloxide (15) and the lignan siringaresinol (16). These compounds were characterized based on analysis of data provided by oneand two-dimensional Nuclear Magnetic Resonance (NMR of H and C), High-resolution Mass Spectrometry, besides comparison with data reported in the literature.

Antifungal Activity of extracts from two Ouratea species on Candida albicans

Article history: Received on: 06/05/2013 Revised on: 22/05/2013 Accepted on: 06/06/2013 Available online: 27/06/2013 Plants are invaluable sources of pharmaceutical products and Brazil, in particular, has yielded an incredible array of plant and animal products that have drawn the attention of ethnopharmacologists from around the world. Ouratea is a genus of tropical plants within the Ochnaceae. Ouratea is widespread throughtout the tropics, with species in Costa Rica, Brazil, Jamaica, and Kenya. The search for compounds with antimicrobial activity is urgent and indispensable for the treatment of infectious diseases caused by microorganisms resistant to traditional antimicrobial drugs. A screening was conducted with organic extracts from two species, from roots and leaves of Ouratea hexasperma var. planchonii Engl. and leaves and branches of Ouratea parviflora Engl., to identify plant extracts with antifungal properties against Candida albicans. Initially, minimal inhibitory concentrations (MICs) were determined in C. albicans cellular suspension in Sabouraud medium, in a range of 0.060-3.0 mg/ml. Fractions OHRMWE (Ethyl acetate fraction) and OHLMWB (Buthanol fraction) obtained by solvents partition of methanol:water extract from Ouratea hexasperma with ethyl acetate from the roots and n-butanol from the leaves, respectively, showed a higher antifungal activity. The antifungal activity of these extracts was also compared in growth delay of C. albicans cultures.