RESUMO
Bioassay-guided fractionation of the leaves of Eugenia rigida yielded three stilbenes, (Z)-3,4,3',5'-tetramethoxystilbene (1), (E)-3,4,3',5'-tetramethoxystilbene (2), and (E)-3,5,4'-trimethoxystilbene (3). Their structures were determined using 1D- and 2D-NMR spectroscopy and HRESIMS. The sterically hindered Z-stereoisomer 1, a new natural product, was prepared by time-dependent photoisomerization of the E-isomer (2) under UV irradiation at λ254 nm, while 2,3,5,7-tetramethoxyphenanthrene (5) was identified at λ365 nm by UHPLC/APCI-MS and NMR spectroscopy. Compounds 1-3 were tested against a panel of luciferase reporter gene assays that assess the activity of many cancer-related signaling pathways, and the Z-isomer (1) was found to be more potent than the E-isomer (2) in inhibiting the activation of Stat3, Smad3/4, myc, Ets, Notch, and Wnt signaling, with IC50 values between 40 and 80 µM. However, both compounds showed similar inhibition against Ap-1 and NF-κB signaling. In addition, 1 demonstrated cytotoxic activity toward human leukemia cells, solid tumor cells of epidermal, breast, and cervical carcinomas, and skin melanoma, with IC50 values between 3.6 and 4.3 µM, while 2 was weakly active against leukemia, cervical carcinoma, and skin melanoma cells. Interestingly, 2 showed antioxidant activity by inhibition of ROS generation to 50% at 33.3 µM in PMA-induced HL-60 cells, while 1 was inactive at 100 µM (vs Trolox 1.4 µM).
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/isolamento & purificação , Estilbenos/isolamento & purificação , Estilbenos/farmacologia , Syzygium/química , Antineoplásicos Fitogênicos/química , Antioxidantes/química , Antioxidantes/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Células HL-60 , Humanos , Concentração Inibidora 50 , Estrutura Molecular , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Ressonância Magnética Nuclear Biomolecular , Folhas de Planta/química , Porto Rico , Espécies Reativas de Oxigênio/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Estereoisomerismo , Estilbenos/químicaRESUMO
Activity-guided fractionation of an ethanol extract of Lycopodium cernuum for Candida albicans secreted aspartic proteases (SAP) inhibition resulted in the identification of six new (1-6) and four known (7-10) serratene triterpenes, along with the known apigenin-4'-O-(2' ',6' '-di-O-p-coumaroyl)-beta-D-glucopyranoside (11). On the basis of spectroscopic analysis, the structures of 1-10 were established as 3beta,14alpha,15alpha,21beta,29-pentahydroxyserratane-24-oic acid (lycernuic acid C, 1), 3beta,14alpha,15alpha,21beta-tetrahydroxyserratane-24-oic acid (lycernuic acid D, 2), 3beta,14beta,21beta-trihydroxyserratane-24-oic acid (lycernuic acid E, 3), 3beta,21beta,29-trihydroxy-16-oxoserrat-14-en-24-methyl ester (lycernuic ketone A, 4), 3alpha,21beta,29-trihydroxy-16-oxoserrat-14-en-24-methyl ester (lycernuic ketone B, 5), 3alpha,21beta,24-trihydroxyserrat-14-en-16-one (lycernuic ketone C, 6), 3beta,21beta-dihydroxyserrat-14-en-24-oic acid (lycernuic acid A, 7), 3beta,21beta,29-trihydroxyserrat-14-en-24-oic acid (lycernuic acid B, 8), serrat-14-en-3beta,21beta-diol (9), and serrat-14-en-3beta,21alpha-diol (10). The 13C NMR data for the known compounds 7 and 8 are reported for the first time. Compounds 1 and 11 showed inhibitory effects against C. albicans secreted aspartic proteases (SAP) with IC50 of 20 and 8.5 microg/mL, respectively, while the other compounds were inactive.
Assuntos
Antifúngicos/isolamento & purificação , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Candida albicans/efeitos dos fármacos , Inibidores Enzimáticos/isolamento & purificação , Lycopodiaceae/química , Plantas Medicinais/química , Inibidores de Proteases/isolamento & purificação , Triterpenos/isolamento & purificação , Acetilação , Antifúngicos/química , Antifúngicos/farmacologia , Cromatografia Líquida de Alta Pressão , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Hidrólise , Concentração Inibidora 50 , Conformação Molecular , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Peru , Inibidores de Proteases/química , Inibidores de Proteases/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Relação Estrutura-Atividade , Triterpenos/química , Triterpenos/farmacologiaRESUMO
A phytochemical investigation of the CHCl(3) fraction of an ethanol extract of the root of Guatteria multivenia furnished nine compounds, of which four are sesquiterpenes (1-4) and five are alkaloids (5-9). Of the four sesquiterpenes, two are new (1, 3), named guatterin A (1) and dihydromadolin-K (3), and two are known (2, 4), identified as madolin-K (2) and madolin-W (4). The five known alkaloids were identified as liriodenine (5), lysicamine (6), lanuginosine (7), guadiscine (8), and O-methylpallidine (9). All the known compounds were isolated from this species for the first time. Structures of the new compounds were determined by extensive NMR studies, including DEPT, COSY, HMQC, HMBC, and NOESY. Compound 7 showed weak inhibitory effect against Candida albicans secreted aspartic proteases (SAP) with IC(50) of 45 microg/mL. Compound 5 was found to have antimicrobial activity against C. albicans, Cryptococcusneoformans, Staphylococcus aureus, and methicillin-resistant S. aureus (MRS) with IC(50)/MIC values of 3.5/6.25, 2.0/12.5, 2.0/3.13, and 2.0/3.13 microg/mL, respectively.