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.

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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.

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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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Cruciferous vegetables, such as broccoli and watercress, have been studied extensively aiming to evaluate their chemopreventive properties. Some of them have already been established using animal models. The ITCs induce Phase II enzymes related to detoxification processes of chemical carcinogens to prevent the start of carcinogenesis. They also exhibit antitumor activity at post-initiation phase, suggesting their additional role(s) in cancer prevention. Sulforaphane is the most extensively studied isothiocyanate, focused in its anti-tumoral activity and it is mainly found in great amounts in broccoli and other cruciferous. In a dose dependent manner, ITCs inhibit the cell viability of human cervical cancer cells, human pancreatic cancer cells, human hepatocellular carcinoma cells, human ovarian cancer cells, and have antiinflammatory properties in the treatment of human T-cell leukemia cells. This protective effect may be due to improved antioxidant status. Although the health effects of diet in humans are generally considered promising, there are definite challenges and limitations of the current data in better understanding of the molecular mechanisms responsible for this effect, together with the possible interactions between different dietary constituents. The survey of relevant patents on the use of isothiocyanates such as sulforaphane for cancer and cardiovascular diseases treatments is also included in this review.