Browsing by Author "Rodriguez, B"
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- A trihomoabietane diterpenoid from Plectranthus grandidentatus and an unusual addition of acetone to the ortho-quinone system of cryptotanshinonePublication . Gaspar-Marques, C; Simoes, MF; Rodriguez, BA new 9 alpha-(2-oxopropyl)abietane derivative (1) has been isolated from an acetone extract of Pleectranthus grandidentatus. Extraction of the plant material and analytical processes carried out in the absence of acetone also revealed the presence of 1 in the plant, thus suggesting that it is a natural product rather than an artifact. Attempts at obtaining Michael adducts between acetone and para-quinone abietane diterpenoids were unsuccessful, whereas treatment of the ortho-quinone cryptotanshinone (3) with acetone under basic conditions yielded compound 2. The structures of 1 and 2 were established by 1D and 2D NMR spectroscopic studies.
- Abietanes from Plectranthus grandidentatus and P-hereroensis against methicillin- and vancomycin-resistant bacteriaPublication . Gaspar-Marques, C; Rijo, P; Simeoes, MF; Duarte, MA; Rodriguez, BThe antimicrobial activity of 10 natural abietanes isolated from Plectranthus grandidentatus and P. hereroensis acetonic extract was evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). The results revealed that the most active diterpenes were coleon U (1), 7 alpha-acetoxy-6 beta-hydroxyroyleanone (2) and horminone (3). Minimum inhibitory concentration (MIC) values ranging 0.98-15.63 mu g/ml were obtained for MRSA clinical strains, and MIC values of 15.63 and 31.25 mu g/ml were obtained for VRE clinical strains. Some structure-activity relationships are emphasized. (c) 2005 Elsevier GmbH. All rights reserved.
- Antimicrobial Activity of 7 alpha-acetoxy-6 beta-hidroxyroyleanone estersPublication . Rijo, P; Gameiro, AP; Simões, MF; Duarte, A; Rodriguez, B
- Effect of abietane diterpenes from Plectranthus grandidentatus on the growth of human cancer cell linesPublication . Marques, CG; Pedro, M; Simoes, MFA; Nascimento, MSJ; Pinto, MMM; Rodriguez, BFive known abietane diterpenes, fatty acid esters of 7alpha-acyloxy-6beta-hydroxyroyleanone (1), grandidone A (2), 7alpha-acetoxy-6beta-hydroxyroyleanone (3), 6beta,7alpha-dihydroxyroyleanone (4), and coleon U (5), isolated from Plectranthus grandidentatus Gurke, were evaluated for their in vitro anti proliferative activity against five human cancer cell lines MCF-7, NCI-H460, SF-268, TK-10, and UACC-62. Coleon U (5) exhibited the strongest effect among all the assayed compounds. The abietane 3 revealed also a strong inhibitory effect while diterpenes 2 and 4 inhibited only slightly the growth of all cancer cell lines.
- Further labdane and kaurane diterpenoids and other constituents from Plectranthus fruticosusPublication . Gaspar-Marques, C; Simoes, MF; Rodriguez, BEight new diterpenoids, one labdane and seven kaurane derivatives, and a new aromadendrane-type sesquiterpenoid have been isolated from the most polar chromatographic fractions of an acetone extract of Plectranthus fruticosus. The structures of the new compounds (1-9) were established mainly by ID and 2D NMR studies and by some chemical transformations. Compounds 6 and 8 were characterized as their methyl ester derivatives (13 and 14, respectively). Most of the isolated compounds and some of their derivatives were tested as antimicrobial agents, but only 19 showed moderate inhibitory activity against Staphylococcus aureus.
- Labdane and kaurane diterpenoids from Plectranthus fruticosusPublication . Gaspar-Marques, C; Simoes, MF; Duarte, A; Rodriguez, BSix new diterpenoids, three labdane and three kaurane derivatives, have been isolated from an acetone extract of Plectranthus fruticosus together with other already known substances. The structures of these compounds (1-5 and 7) were established mainly by spectroscopic means, particularly by 1D and 2D NMR studies, as well as by some chemical correlations with known diterpenoids. The physical and spectroscopic data of the derivative 11, obtained by hydrolysis of the labdane 2, were identical to those reported for a compound previously isolated from Croton joufra, to which structure 12 had been established erroneously by other authors. Several of the isolated compounds were tested as antimicrobial agents against three bacteria strains and one yeast strain, but only 4 showed a moderate inhibitory activity against Staphylococcus aureus.
- Neoclerodane and labdane diterpenoids from Plectranthus ornatusPublication . Rijo, P; Gaspar-Marques, C; Simoes, MF; Duarte, A; Apreda-ojas, MD; Cano, FH; Rodriguez, BThree new diterpenoids, a neoclerodane and two labdane derivatives, have been isolated from an acetone extract of Plectranthus ornatus. The structures. of these compounds (plectrornatins A-C, 1-3, respectively) were established mainly by spectroscopic means, particularly by 1D and 2D NMR studies and, in the case of the neoclerodane 1, by an X-ray diffraction analysis. Compounds. 1 and 3 showed moderate antimicrobial against five Candida species and selected Gram negative and Gram positive bacteria strains.
- Structural and spectral assignment of three forskolin-like diterpenoids isolated from Plectranthus ornatusPublication . Rijo, P; Simoes, MF; Rodriguez, BThree labdane diterpenoids were isolated from an acetone extract of Plectranthus ornatus. Their structures, closely related to that of forskolin, were determined by NMR studies. Unambiguous and complete assignments of the H-1 and C-13 NMR chemical shifts for these substances are presented. The assignments are based on 2D shift-correlated [H-1,H-1-COSY,H-1,C-13-gHSQC-(1)J (C,H), H-1, C-13-gHMBC-(n)J (C,H) (n = 2 and 3)] and NOE experiments. Copyright (c) 2005 John Wiley & Sons, Ltd.