Roqueline Rodrigues Silva de Miranda

A new friedelane triterpenoid from the branches of Maytenus gonoclada (Celastraceae)

A new friedelane type triterpene, 3,16-dioxo-12α-hydroxyfriedelane was isolated from the chloroform extract of branches of Maytenus gonoclada Martius (Celastraceae) together with nine known compounds: 3, 11-dioxofriedelane, 3, 16-dioxofriedelane, 3, 12-dioxofriedelane, 3-oxo-12α,29-dihydroxyfriedelane, 3-oxofriedelane (friedelin), 3β-hydroxyfriedelane, 3-oxo-12α-hydroxyfriedelane and 3β-hydroxylup-20(29)-ene (lupeol) and a mixture of long chain hydrocarbons. The structure and stereochemistry of the new friedelane triterpene were established from the 1H NMR and 13C NMR spectra including two-dimensional experiments (HSQC, HMBC and NOESY) and high resolution mass spectrometry.

Evaluation of antibacterial activity of "Mangabarana" Austroplenckia populnea Reissek (Celastraceae)

Austroplenckia populnea (Mangabarana) e popularmente utilizada em Minas Gerais, Brasil, para o tratamento de disenterias. A ela tambem sao atribuidas propriedades antitumoral e antiulcera. Extratos de partes desta planta obtidos com solventes de diferentes polaridades e triterpenos pentaciclicos (TTPCs) isolados destes, por metodos fitoquimicos foram submetidos a testes de atividade antibacteriana. Os resultados mostraram a existencia desta atividade e abriram perspectivas para a continuidade dos estudos com outros compostos orgânicos isolados desta planta.

Stereochemistry of 16α-Hydroxyfriedelin and 3-Oxo-16- methylfriedel-16-ene Established by 2D NMR Spectroscopy

Friedelin (1), 3β-friedelinol (2), 28-hydroxyfriedelin (3), 16α-hydroxyfriedelin (4), 30-hydroxyfriedelin (5) and 16α,28-dihydroxyfriedelin (6) were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl3 solution, 16α-hydroxyfriedelin (4) reacted turning into 3-oxo-16-methylfriedel-16-ene (7). This is the first report of a dehydration followed by a Nametkin rearrangement of a pentacyclic triterpene in CDCl3 solution occurring in the NMR tube. These seven pentacyclic triterpenes was identified through NMR spectroscopy and the stereochemistry of compound 4 and 7 was established by 2D NMR (NOESY) spectroscopy and mass spectrometry (GC-MS). It is also the first time that all the 13C-NMR and 2D NMR spectral data are reported for compounds 4 and 7.

Triterpenes from Maytenus gonoclada and their attractive effects on Tenebrio molitor

Bioactive metabolites have been isolated from plants of the genus Maytenus (Celastraceae), such as maytansinoids with insecticide activity, sesquiterpene pyridine alkaloids with insect antifeedant activity, and nortriterpene quinonemethides, which show antimicrobial activity [1]. Despite the great diversity of plant metabolites showing several biological activities, no compound with the friedelane skeleton presenting attractive-repellent effects has been described until now [2]. Previous phytochemical studies with aerial parts of Brazilian Maytenus species showed mainly pentacyclic triterpenes (PCTT) of the friedelane series, which are regarded as the characteristic constituents of plants belonging to this genus. It is worth noting that the PCTT were identified as the principal constituents of some Brazilian Maytenus sp. Maytenus gonoclada Martius (Celastraceae), which can be found in the “cerrado” region and rupestrian fields of Southeast and Northeastern Brazil. It is a polymorphic tree, usually spiny, the spines sometimes end in short shoots. The leaves alternate and are extipulate. The flowers are hermaphrodite in axillary, solitary, or fascicled dichotomous cymes; the calix is 4-5-lobed. The petals are 4–5, spreading. The stamens are 4–5, inserted on the margin of the disc or slightly below it; the filaments are slender and broad [3]. In this work we report the isolation, from the aerial parts of M. gonoclada, of seven compounds of the friedelane series: 3-oxofriedelane (1) [4], 3 -hydroxyfriedelane (2) [5], 3,11-dioxofriedelane (3), 3,16-dioxofriedelane (4) [6], 3-oxo-12 -hydroxyfriedelane (5) [7], 3-oxo-28-hydroxyfriedelane (6) [8], and 3-oxo-29-hydroxyfriedelane (7) [9]; two members of the lupane series, 3 -stearyloxy-lup-20(29)-ene (8) and lupeol (9) [10]; a taraxane, 3 -taraxerol (10) [11]; two ursanes, -amyrin (11) [6] and 3 -stearyloxy-urs-12-ene (12) [12]; and oleanane -amyrin (13) [13]. -Sitosterol (14) [14], the polyol dulcitol or galactitol (15) [15], and palmitic acid (16) [16] were also chemically characterized. Two long-chain hydrocarbons with 28 and 36 carbons, respectively (17), were identified through high-resolution gas chromatography (GC). The hexane extract and constituents of M. gonoclada were tested for their attractive-repellent effects on the larvae of Tenebrio molitor (L.) (Coleoptera: Tenebrionidae). The hexane extract, the mixture of 3,11-dioxofriedelane and 3,16-dioxofriedelane, and the terpene 3-oxo12 -hydroxyfriedelane showed attractive effects on these larvae. Phytochemical studies demonstrated that the aerial parts of Brazilian Maytenus species consist mainly of triterpenes of the friedelane series, which are regarded as the characteristic constituents of plants belonging to this genus [2, 17]. It is worth noting that the pentacyclic triterpenes were identified as the principal constituents of Brazilian Maytenus sp. In the present work, we report the isolation of 13 known pentacyclic triterpenes: seven friedelanes (1–7), two lupanes (8 and 9), one taraxane (10), two ursanes (11 and 12), and the oleanane (13) obtained from M. gonoclada. Compounds 1 to 13 give a Liebermann–Buchard (LB) positive test for pentacyclic triterpenes, and 14 for steroids [18]. The 1H NMR spectra of constituents 1–7 showed a hydrogen signal at ~ H 0.87 (d, J = 6.8 Hz), which is in accord with the C-23 methyl group of members of the friedelane series. The 13C NMR data confirmed that compounds 1–7 are friedelane derivatives [6]. The 1H NMR spectra of compounds 8 and 9 showed signals at H 4.6 and H 4.7 that are characteristics of lupane triterpenes [19]. The presence of signals at C 150.98 and C 109.36 observed in 13C NMR spectra confirmed the lupane skeleton of these compounds [10].

Constituents of fruit pulp of Maytenus salicifolia and complete 1D/2D NMR data of 3β-hydroxy-D:B-friedo-olean-5-ene.

A mixture of long-chain hydrocarbons constituted by nonacosane (29C, 7.5%), hentriacontane (31C, 48.3%), and tritriacontane (33C, 30.1%), the ester 1′-acetyloxymethylpentacosa-20′-enyl 10-hydroxydecanoate (2), β-amyrin (3), friedelin (4), and lupeol (5), and 3β-hydroxy-D:B-friedo-olean-5-ene (6) were identified as constituents of fruits of Maytenus salicifolia Reissek (Celastraceae). The structural formula and the stereochemistry of compound 6 were established by the data obtained through 1H and 13C NMR spectroscopy, including DEPT-135 and 2D (HMQC, HMBC, and NOESY) experiments. By analysis of the spectral data, it was possible to correct seven chemical shift assignments of compound 6, which were erroneous attributed and published in the scientific literature.

Changes in the essential oil composition of leaves of Echinodorus macrophyllus exposed to

Leaves of Echinodorus macrophyllus (Kunth) Micheli, Alismataceae, were exposed to different doses of γ-radiation (0.00, 1.00, 3.00, 5.00, 10.00, and 20.00 kGy) and the chemical composition of their essential oils was investigated. The extractive process of the essential oil was more favored when the leaves were irradiated. The essential oil components were identified by correlation between GC-FID data and retention parameters obtained from the Kovats method. Moreover, GC-MS analyses of the essential oils were correlated with fragmentation profiles in the NIST standard mass fragmentation data bank. The essential oil of E. macrophyllus contains biologically active constituents of different chemical classes. Acyclic monoterpenes and sesquiterpenes showed increase in concentration when the leaves were exposed to γ-radiation. On the other hand, the component concentrations of some chemical classes were lightly decreased, i.e., for bicyclic monoterpenes, diterpenes, triterpenes, carboxylic esters, and carotenoid derivatives.

Antimicrobial activity of synthetic bornyl benzoates against Trypanosoma cruzi

Abstract We report here for the first time the in vitro effects of (1S,2R,4S)-1,7,7-trimethyl-bicyclo[2·2·1]heptan-2-yl-3′,4′,5′-trimethoxy benzoate (1) and (1S,2R,4S)-1,7,7-trimethyl-bicyclo[2·2·1]heptan-2-yl benzoate (2) on the growth and ultrastructure of Trypanosoma cruzi. These two synthetic compounds exerted an antiproliferative effect on the epimastigote forms of the parasite. The ICs50/72h of two synthetic L-bornyl benzoates, 1 and 2, was 10·1 and 12·8 μg/ml, respectively. Both compounds were more selective against epimastigotes than HEp-2 cells. Ultrastructural analysis revealed intense cytoplasmic vacuolization and the appearance of cytoplasmic materials surrounded by membranes. The treatment of peritoneal macrophages with compounds 1 and 2 caused a significant decrease in the number of T. cruzi-infected cells. L-Bornyl benzoate derivatives may serve as a potential source for the development of more effective and safer chemotherapeutic agents against T. cruzi infections.