An NMR study of 3α‐ and 3β‐friedelinol is described. In addition to conventional 1D NMR methods, 2D shift‐correlated NMR experiments HMQC [(1J(C,H)], HMBC [nJ(C,H); n=2 and 3] and 2D 1H,1H‐NOESY were used for 1H and 13C chemical shift assignments of these triterpenes. Copyright © 2000 John Wiley & Sons, Ltd.

RESUMO: Utilizando a técnica de hidrodestilação, usando um adaptador Clevenger, foram extraídos óleos essenciais das espécies Pimenta dioica (folhas e frutos) e Syzygium aromaticum (botões florais, talos e folhas). A composição química dos óleos foi determinada através da analise CG-EM. Os teores de óleos essenciais variaram de 0,97 a 1,41% e 2,30 a 15,40% nas espécies Pimenta dioica e Syzygium aromaticum, respectivamente. O componente majoritário presente nessas espécies foi o eugenol, variando de 72,87 a 90,41%. Syzygium aromaticum forneceu maior teor de óleo essencial rico em eugenol. Em quantidades menores foram também encontrados chavicol e β-cariofileno.Unitermos: Syzygium aromaticum, Pimenta dioica, Myrtaceae, eugenol, Brasil, óleo essencial.ABSTRACT: "Volatile chemical constituents of rich spices in eugenol". Essential oils were extracted from the leaves and fruits of Pimenta dioica and leaves, stalks and floral buttons from Syziguim aromaticum by hydrodistillation using a Clevenger apparatus. The essential oil compositions were determined by CG-MS analyses. The yield varied from 0.97 to 1.41% and from 2.30 to 15.40% in the P. dioica and S. aromaticum, respectively. In both species the major component was the eugenol, varied from 72.87 to 90.41%, being richer the essential oil extracted from S. aromaticum. Chavicol and β-caryophyllene were identified in low percentage.

Leaves of Maytenus robusta (Celastraceae) were subjected to phytochemical investigation mainly directed at the isolation of pentacyclic triterpenes. The compounds friedelin (1), β-friedelinol (2), 3-oxo-21β-H-hop-22(29)-ene (7), 3,4-seco-friedelan-3,11β-olide (8), 3β-hydroxy-21β-H-hop-22(29)-ene (9), 3,4-seco-21β-H-hop-22(29)-en-3-oic acid (10), 3,4-seco-friedelan-3-oic acid (11), and sitosterol were identified in the hexane extract of M. robusta leaves. Compounds 8 and 9 are described herein for the first time. The structure and stereochemistry of both compounds were experimentally established by IR, HRLC-MS, and 1D (1H, 13C, and DEPT 135) and 2D (HSQC, HMBC and COSY) NMR data and supported by correlations with carbon chemical shifts calculated using the DFT method (BLYP/6-31G* level). Compounds 7 and 10 are also described for the first time, and their chemical structures were established by comparison with NMR data of similar structures described in the literature and correlations with BLYP/6-31G* calculated carbon chemical shifts. Compound 9, a mixture of 11 and sitosterol, and 3β,11β-dihydroxyfriedelane (4) were evaluated by the Ellman’s method and all these compounds showed acethylcholinesterase inhibitory properties.

Mayaro fever, caused by Mayaro virus (MAYV) is a sub-lethal disease with symptoms that are easily confused with those of dengue fever, except for polyarthralgia, which may culminate in physical incapacitation. Recently, outbreaks of MAYV have been documented in metropolitan areas, and to date, there is no therapy or vaccine available. Moreover, there is no information regarding the three-dimensional structure of the viral proteins of MAYV, which is important in the search for antivirals. In this work, we constructed a three-dimensional model of protein C of MAYV by homology modelling, and this was employed in a manner similar to that of receptors in virtual screening studies to evaluate 590 molecules as prospective antiviral agents. In vitro bioassays were utilized to confirm the potential antiviral activity of the flavonoid epicatechin isolated from Salacia crassifolia (Celastraceae). The virtual screening showed that six flavonoids were promising ligands for protein C. The bioassays showed potent antiviral action of epicatechin, which protected the cells from almost all of the effects of viral infection. An effective concentration (EC) of 0.247 μmol/mL was observed with a selectivity index (SI) of 7. The cytotoxicity assay showed that epicatechin has low toxicity, with a 50% cytotoxic concentration (CC) greater than 1.723 µmol/mL. Epicatechin was found to be twice as potent as the reference antiviral ribavirin. Furthermore, a replication kinetics assay showed a strong inhibitory effect of epicatechin on MAYV growth, with a reduction of at least four logs in virus production. Our results indicate that epicatechin is a promising candidate for further testing as an antiviral agent against Mayaro virus and other alphaviruses.

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