Casearia sylvestris (Salicaceae), popularly known as "guaçatonga", is a plant widely used in folk medicine to treat various diseases, including cancer. The present work deals with the chemical composition as well as the cytotoxic evaluation of its essential oil, its main constituent and derivatives. Thus, the crude essential oil from leaves of C. sylvestris was obtained using a Clevenger type apparatus and analyzed by GC/MS. This analysis afforded the identification of 23 substances, 13 of which corresponded to 98.73% of the total oil composition, with sesquiterpene α-zingiberene accounting for 50% of the oil. The essential oil was evaluated for cytotoxic activity against several tumor cell lines, giving IC 50 values ranging from 12 to 153 μg/mL. Pure α-zingiberene, isolated from essential oil, was also evaluated against the tumor cell lines showing activity for HeLa, U-87, Siha and HL60 cell lines, but with IC 50 values higher than those determined for the crude essential oil. Aiming to evaluate the effect of the double bonds of α-zingiberene on the cytotoxic activity, partially hydrogenated α-zingiberene (PHZ) and fully hydrogenated α-zingiberene (THZ) derivatives were obtained. For the partially hydrogenated derivative only cytotoxic activity to the B16F10-Nex2 cell line (IC 50 65μg/mL) was detected, while totally hydrogenated derivative showed cytotoxic activity for almost all cell lines, with B16F10-Nex2 and MCF-7 as exceptions and with IC 50 values ranging from 34 to OPEN ACCESSMolecules 2013, 18 9478 65 μg/mL. These results indicate that cytotoxic activity is related with the state of oxidation of compound.

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Essential oils of ripe fruits from Schinus terebinthifolius (Anacardiaceae), obtained using a pilot extractor and a Clevenger apparatus were chemically characterized. Due the high amount of (-)- α-pinene in both oils, this monoterpene was tested against the protozoan parasite Trypanosoma cruzi, showing a moderate potential (IC50 63.56 µg/mL) when compared to benznidazole (IC50 43.14 µg/mL). Otherwise, (-)- α-pinene oxide did not showed anti-trypanosomal activity (IC50 > 400 µg/mL) while (-)-pinane showed an IC50 of 56.50 µg/mL. The obtained results indicated that the epoxydation of α-pinene results to the loss of the anti-parasitic activity while its hydrogenation product, contributed slightly to the increased activity

The preparation of new bis[(diphenylphosphinoyl)methyl] sulfides, selenides, and tellurides is described by the reaction of (diphenylphosphinoyl)methyl p-toluenesulfonate with sodium chalcogenides. The title compounds are subjected to Horner-Wittig-type reactions with aldehydes and ketones to give symmetrical divinylic sulfides, selenides, and tellurides

Os estudos cristalográficos mostram que o poliedro de coordenação ao redor do átomo de Te, em cada um dos compostos (p-tol)Te[C(H)=C(Cl)Ph]X 2 , com X = Cl (1), Br (2) e I (3), é uma Ψ-bipirâmide pentagonal distorcida. O grupo vinil em (1) adota uma configuração E o que impede a formação de uma interação intramolecular Te … Cl e em seu lugar é encontrada uma interação intramolecular Te … p. O poliedro de coordenação é formado por um arranjo linear Cl-Te-Cl com o plano pentagonal definido por dois átomos de C dos substituintes orgânicos, um contato intermolecular Te … Cl, uma interação Te … p e um par isolado de elétrons estereoquimicamente ativo. Geometrias de coordenação semelhantes são encontradas para as estruturas com X = Br (2) e I (3), mas a interação p é substituída por uma interação intramolecular Te … Cl devido à adoção de uma configuração Z em torno da ligação vinil. As diferenças nas estruturas são facilmente explicadas em termos de efeitos eletrônicos. Estudos de docking em catepsina B com (1')-(3'), ou seja, compostos 1 a 3 em que há um haleto a menos ligado ao átomo de Te, mostram que há uma ligação eficiente com a proteína pela formação da ligação covalente Te-S Cys29 com a estabilização proporcionada por uma combinação de interações N-H … p, C-H … p e Cl vinyl … H. Estes resultados são comparáveis aos obtidos com inibidores conhecidos da catepsina B o que sugere que os compostos estudados têm potencial atividade biológica.Crystallography shows that the Te atom in each of (p-tol)Te[C(H)=C(Cl)Ph]X 2 , for X = Cl (1), Br (2) and I (3), is within a distorted Ψ-pentagonal bipyramidal geometry. An E configuration for the vinyl group in (1) precludes the formation of an intramolecular Te … Cl interaction so that an intramolecular Te … p interaction is found instead. The coordination environment features a linear Cl-Te-Cl arrangement with the pentagonal plane defined by the two C atoms of the organic substituents, an intermolecular Te … Cl contact, a Te … p interaction and a stereochemically active lone pair of electrons. In the X = Br (2) and I (3) structures, similar coordination geometries are found but the Te … p contact is replaced by an intramolecular Te … Cl contact owing to the adoption of a Z configuration about the vinyl bond. The differences in structure are readily explained in terms of electronic effects. Docking studies of cathepsin B with (1')-(3'), i.e. 1-3 less one Te-bound halide, show efficient binding through the agency of covalent Te-S Cys29 bonds with stabilization afforded by a combination of N-H … p, C-H … p and Cl vinyl … H interactions. These results comparable favorably with known inhibitors of cathepsin B suggesting the title compounds have potential biological activity.Keywords: organotellurium-dihalides, docking studies, cathepsin B, crystal structures, supramolecular arrangements 2-Chlorovinyl Tellurium Dihalides, (p-tol)Te[C(H)=C(Cl)Ph]X 2 for X = Cl, Br and I J. Braz. Chem. Soc. 2156 IntroductionOrganotellurium halides comprise an interesting class of compounds owing...